HS2.1.5 | Hydrology and climate in drylands: global and Mediterranean perspectives
EDI
Hydrology and climate in drylands: global and Mediterranean perspectives
Co-organized by AS1/CL2/GM7/NH1
Convener: Moshe ArmonECSECS | Co-conveners: Lionel Jarlan, Andries Jan De VriesECSECS, María José PoloECSECS, Pedro AlencarECSECS, Said Khabba, Rodolfo NóbregaECSECS
Orals
| Wed, 17 Apr, 10:45–12:30 (CEST), 14:00–15:35 (CEST)
 
Room 3.16/17, Thu, 18 Apr, 08:30–10:05 (CEST)
 
Room 3.16/17
Posters on site
| Attendance Thu, 18 Apr, 16:15–18:00 (CEST) | Display Thu, 18 Apr, 14:00–18:00
 
Hall A
Posters virtual
| Attendance Thu, 18 Apr, 14:00–15:45 (CEST) | Display Thu, 18 Apr, 08:30–18:00
 
vHall A
Orals |
Wed, 10:45
Thu, 16:15
Thu, 14:00
Water is a strategic issue in drylands, where ecosystems and their inhabitants strongly rely on the scarce and often intermittent water availability or its low quality. The characteristics of drylands increase their vulnerability to climate change and susceptibility to the impact of short- to long-term extreme events and processes, such as floods, droughts, and desertification. These events can reshape the landscape through the mobilisation of surface sediments, deposits of which preserve archives of past Earth system states, including changes in the extent of deserts. Over the last century, anthropogenic modifications of all kinds and intensities have affected surface conditions. In drylands and Mediterranean hydrosystems, agricultural water use is constantly increasing threatening the sustainability of the surface and groundwater reservoirs, and their hydrology is then continuously evolving. Nevertheless, the study of hydroclimatic processes in drylands remains at the periphery of many geoscientific fields. A proper understanding of the hydrological, hydrometeorological and (paleo)climatic processes in these regions is a cornerstone to achieving the proposed sustainable development goals we set for the end of this century.

This session welcomes contributions from scientific disciplines addressing any of the drylands' full range of environmental and water-related processes. The purpose is to foster interdisciplinary research and expand knowledge and methods established in individual subdisciplines. We will address hydrological issues across global drylands, and devote a section of our session to a geographical focus on the Mediterranean region to analyse the changes in hydrologic processes and fluxes unique to that region.

Orals: Wed, 17 Apr | Room 3.16/17

Chairpersons: Moshe Armon, Pedro Alencar
10:45–10:50
Paleo desert hydrology: from Ma to centuries
10:50–11:10
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EGU24-11799
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ECS
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solicited
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Highlight
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On-site presentation
Monika Markowska, Hubert B. Vonhof, Huw S. Groucutt, Michael D. Petraglia, Denis Scholz, Michael Weber, Axel Gerdes, Richard Albert, Julian Schroeder, Yves S. Krüger, Anna Nele Meckler, Jens Fiebig, Matthew Stewart, Nicole Boivin, Samuel L. Nicholson, Paul S. Breeze, Nicholas Drake, Julia C. Tindall, Alan M. Haywood, and Gerald Haug

Drylands cover almost half of Earth’s land surfaces, supporting ~30% of the world’s population. The International Panel on Climate Change predicts increasing aridification and expansion of drylands over the course of this century. As we approach new climate states without societal precedent, Earth’s geological past may offer the best tool to understand hydroclimate change under previously, allowing us to elucidate responses to external forcing. Paleo-records from previously warm and high-CO2 periods in Earth’s past, such as the mid-Pliocene (~3 Ma), point towards higher humidity in many dryland regions. 

Here, we examine desert speleothems from the hyper-arid desert in central Arabia, part of the largest near-continuous chain of drylands in the world, stretching from north-western Africa to the northern China, to elucidate substantial and recurrent humid phases over the past 8 million years. Independent quantitative paleo-thermometers suggest that mean annual air temperatures in central Arabia were approximately between 1 to 5 °C warmer than today. The analyses of the isotopic composition (δ18O and δ2H) of speleothem fluid inclusion waters, representing ‘fossil rainwater’, reveal an aridification trend in Arabia from the Late Miocene to Late Pleistocene during Earth’s transition from a largely ‘ice-free’ northern hemisphere to an ‘ice-age’ world. Together, our data provide evidence for recurrent discrete wetter intervals during past warmer periods, such as the Pliocene. Data-model comparisons allow us to assess the agreement between our paleoclimate data and climate model output using the HadCM3 isotope-enabled model simulations during past ‘warmer worlds’ – namely the mid-Piacenzian warm period (3.264 to 3.025 Ma). To assess the hydroclimate response to external forcing, we examine model output from a series of sensitivity experiments with different orbital configurations allowing us to postulate the mechanisms responsible for the occurrence of humid episodes in the Arabian desert, with potential implications for other dryland regions at similar latitudes. Together, our approach unveils the long-term controls on Arabian hydroclimate and may provide crucial insights into the future variability.

How to cite: Markowska, M., Vonhof, H. B., Groucutt, H. S., Petraglia, M. D., Scholz, D., Weber, M., Gerdes, A., Albert, R., Schroeder, J., Krüger, Y. S., Meckler, A. N., Fiebig, J., Stewart, M., Boivin, N., Nicholson, S. L., Breeze, P. S., Drake, N., Tindall, J. C., Haywood, A. M., and Haug, G.: Exploring the mechanisms controlling dryland hydroclimate in past 'warmer worlds', EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11799, https://doi.org/10.5194/egusphere-egu24-11799, 2024.

11:10–11:20
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EGU24-9899
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On-site presentation
Kathryn Fitzsimmons, Markus Fischer, Colin Murray-Wallace, Edward Rhodes, Tobias Lauer, Maike Nowatzki, Kanchan Mishra, and Nicola Stern

Australia is big, flat, old and arid: it is the driest inhabited continent on Earth. The catastrophic flooding of recent years has demonstrated not only the potential for extreme conditions at both ends of the hydroclimatic scale, but also how little we understand of the interplay between climatic, hydrological, and surface-process mechanisms affecting this part of the world. We know still less about long-term hydrological dynamics, particularly for the dry inland where water resources are scarce and land surfaces are susceptible to erosion, requiring careful management.

Records of past hydrological variability can help inform us about changing hydroclimate states and their impact on the land surface. The Willandra lakes system, located on the desert margins of southeastern Australia, is one of the few dryland areas which preserves long-term sedimentary records of hydrologic change. The headwaters of these lakes lie in the temperate highlands hundreds of kilometres to the east; as a result, lake filling and drying reflects the interaction between rainfall in the watershed and hydrologic connectivity across the catchment and between the lakes. Environmental change in the Willandra is recorded in the sediments of the lake shoreline dunes, preserved as semi-continuous deposition of different lake facies over 60,000 years.

Here we investigate long-term hydrologic connectivity across the Willandra lakes and their catchment. Our approach uses a novel integration of lake-level reconstruction based on lunette sedimentology, stratigraphy and luminescence geochronology, with hydrologic and palaeoclimatic modelling of key event time slices over the last 60 ky. We characterize the land-surface response to various hydroclimate states, so improving our understanding of dryland atmosphere-hydrosphere interactions.

How to cite: Fitzsimmons, K., Fischer, M., Murray-Wallace, C., Rhodes, E., Lauer, T., Nowatzki, M., Mishra, K., and Stern, N.: 60,000 years of hydrologic connectivity on the Australian dryland margins: the case of the Willandra Lakes World Heritage Area, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9899, https://doi.org/10.5194/egusphere-egu24-9899, 2024.

11:20–11:30
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EGU24-13979
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On-site presentation
Yu Liu

    The Yellow River (YR) is 5464 km long and the cradle of Chinese civilization. It is also well known for being the most sediment-laden river and having the largest vertical drop over its course. Although the YR accounts for only 3% of China’s water resources, it irrigates 13% of its cropland. Exceptional historical documents have recorded frequent occurrence of YR flooding events that resulted in huge losses of lives and property.
    The earliest observational record of YR runoff, beginning in 1919 at the Shanxian gauge station, is too short to study centennial-scale variability. Since the start of the Anthropocene in the 1960s, frequent human activities have resulted in large deviation between observed streamflow. The reconstruction of annual historical natural runoff of the YR is necessary to quantify the amount of anthropogenic YR water consumption in recent decades. Tree rings, with the merits of accurate dating and annual resolution, have been widely used in runoff reconstruction worldwide. In this study, 31 moisture-sensitive tree-ring width chronologies, including 860 trees and 1707 cores, collected within the upper-middle YR basins were used to reconstruct natural runoff for the middle YR course over the period 1492–2013 CE.
    The reconstruction provides a record of natural YR runoff variability prior to large-scale human interference. Most of the extreme high/low runoff events in the reconstruction can be verified with historical documents. The lowest YR flow since 1492 CE occurred during 1926–1932 CE and the YR runoff in 1781 is the highest. These two extreme values could be regarded as a benchmark for future judicious planning of water allocation. Since the late 1980s, observed YR runoff has fallen out of its natural range of variability, and there was even no water flow for several months each year in the lower YR course during 1995 to 1998. Especially concerning was that the inherent 11-year and 24-year cycles of YR became disordered following the severe drought event in late 1920s, and eventually disappeared after the 1960s.
    Year-to-year variability in YR water consumption by human activities (WCHA) was quantified, which showed good association between crop yields and acreage in Ningxia and Inner Mongolia irrigation regions. Meanwhile, WCHA was strongly negatively correlated with sediment load at Toudaoguai and Shanxian stations, which led to a 58% reduction of sediment load in Toudaoguai (upper reach) and 29% in Shanxian (middle reach). 
    If human activities continue to intensify, future YR runoff will be further reduced, and this will negatively impact agriculture, human lives, and socioeconomic development in the middle and lower basins of the YR. To reduce the risk of recurring cutoff of streamflow in the YR lower basin, water should be allocated judiciously. Our reconstructed YR natural runoff series are important for future YR water resource management. In addition, our results also provide an important model of how to distinguish and quantify anthropogenic influence from natural variability in global change studies.

How to cite: Liu, Y.: Changes and attribution of natural runoff in the Yellow River over the past 500 years, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13979, https://doi.org/10.5194/egusphere-egu24-13979, 2024.

11:30–11:40
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EGU24-14189
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On-site presentation
Qiufang Cai and Yu Liu

    Recurrent droughts in history, especially climatic aridity since the mid-20th century have aroused great social anxiety about the water resources in the Chinese Loess Plateau (CLP). Given lacking of extended instrumental-like records, new precipitation reconstructions in the CLP are badly needed for objectively evaluating the current precipitation situation, understanding the spatial-temporal differences, and serving for predicting the future. Here we present a tree-ring-based 248-year regional precipitation reconstruction (P8–7) in the Heichashan Mountain, which can significantly represent the past dry-wet variations in the eastern CLP (ECLP). P8–7 explains 48.72% of the instrumental record, reveals a wetting trend since the early 2000s and attains the second wettest period over the past 248 years in 2014–2020 AD. The 1920s/2010s is recorded as the driest/wettest decade. 1910–1932 AD ranks as the driest period over the past centuries. The 19th century is comparatively wet while the 20th century is dry. Precipitation in the ECLP and western CLP (WCLP) has changed synchronously over most time of the past two centuries. However, regional difference exists in the 1890s–1920s when a gradually drying occurred in the ECLP, while not evident in the WCLP, although the 1920s megadrought occurred in the CLP. Moreover, the 20th-century drying in the ECLP begins in the 1950s, later than the WCLP. It reveals that P8–7 variability is primarily influenced by the Asian Summer Monsoon and related large-scale circulations. The seismic phase shift of the contemporaneous Northern Hemispheric temperature may also be responsible for the 1920s megadrought.

How to cite: Cai, Q. and Liu, Y.: Hydroclimatic characteristics on the Chinese Loess Plateau over the past 250 years inferred from tree rings, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14189, https://doi.org/10.5194/egusphere-egu24-14189, 2024.

Dynamics of (sub)surface water and droughts
11:40–11:50
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EGU24-1185
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ECS
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On-site presentation
Yujie Yan and Yiben Cheng

Desertification on the Mongolian Plateau is deepening, and sand and dust have great negative impacts on many countries in East Asia. Based on meteorological and socio-economic data in the context of climate change, this study analyzed the driving mechanisms and impacts of desertification and water body area response on the Mongolian Plateau using, among others, the GTWR model. The following conclusions were drawn: the area of the Mongolian Plateau showed a decreasing trend from 1990 to 2019, and the number of lakes larger than 1 km2 decreased by 173 or 537.3 km2 in Inner Mongolia, and by 737 or 2875.1 km2 in Mongolia, and all of them were dominated by lakes of 1-10 km2; and the analysis of the correlation between the area of the water bodies showed that the The reasons driving the change of water body area in Inner Mongolia Autonomous Region and Mongolia are similar and different, soil moisture and precipitation have obvious promotion effects, economic development and livestock numbers have different degrees of negative impacts on different countries; The GTWR model is used to represent the impacts of different influencing factors on the water body area in time and space, and the evaporation and GDP are shifted from slight inhibition to promotion, and the population and temperature are both inhibited. Soil moisture and livestock numbers are contributing; Surface water resource monitoring is important to deepen the desertification of the Mongolian Plateau and to provide better water resource recommendations and protection measures for the Mongolian Plateau.

How to cite: Yan, Y. and Cheng, Y.: Study of water body area changes in the desertification process of the Mongolian Plateau and analysis of driving factors, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1185, https://doi.org/10.5194/egusphere-egu24-1185, 2024.

11:50–12:00
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EGU24-8825
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ECS
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On-site presentation
Paula Gabriela Cordoba Ariza, Ramon J. Batalla, Sergi Sabater, and Josep Mas-Pla

Mediterranean basins face significant water scarcity which requires examining long-term data to evaluate their trends in water availability and quality and assess management options. In this presentation, we explore the historical streamflow changes, the influencing climatic —streamflow, precipitation, temperature, and evapotranspiration (PET and AET)— and land-use factors, and the evolution of surface water quality in the Onyar River (Inner Catalan basins, NE Spain; 295 km2) during the last decades (1960-2020).

Results highlight a consistent decline in streamflow, most pronounced over the last two decades, accompanied by an increase in PET, and a probable decrease in groundwater recharge. These changes co-occurred with higher concentrations of river water ammonium and nitrate. We attribute these patterns to changes in land use such as afforestation and intensive fertilization, as well as increased groundwater withdrawal, particularly during irrigation seasons. Additional factors include growing urban water demand and the discharges of treated wastewater back into the river system. Evaluation of the relationship between groundwater and surface water using end-member mixing analysis of hydrochemical data points out an interesting scale-dependence behaviour: groundwater baseflow from alluvial formations was relevant in the smallest subbasins, whereas regional groundwater flow involving deeper aquifers could significantly contribute to stream discharge in the lowest zones of the basin. Since water balance alteration in the future climate scenarios will reduce the contribution of the headwater flow as well as groundwater storage and baseflow generation, reclaimed wastewater shows up as a relevant source to maintain stream runoff, yet its quality is low and might not be properly diluted by rainfall originated runoff.

These observations provide a comprehensive overview of the declining water quantity and quality in the Onyar River network, attributing these trends to an interplay of climatic and anthropogenic factors. They urge for integrated water resources management strategies to mitigate the implications of these environmental changes, such as protecting baseflow generating areas as well as controlling reclaimed wastewater quality.

Funding: G. Córdoba-Ariza acknowledges funding from Secretariat of Universities and Research from Generalitat de Catalunya and European Social Fund for her FI fellowship (2022 FI_B1 00105). 

How to cite: Cordoba Ariza, P. G., Batalla, R. J., Sabater, S., and Mas-Pla, J.: Assessing stream water scarcity and groundwater roles under global change in a Mediterranean watershed: the Onyar River basin (NE Catalonia, Spain), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8825, https://doi.org/10.5194/egusphere-egu24-8825, 2024.

12:00–12:10
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EGU24-4794
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ECS
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On-site presentation
Vegetation Dynamics Regulate Baseflow Seasonal Characteristics in the Chaohe Watershed of Northern China
(withdrawn)
Wenxu Cao, Qinghe Li, Hang Xu, and Zhiqiang Zhang
12:10–12:20
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EGU24-7068
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ECS
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On-site presentation
Xiaohan Yu, Xiankui Zeng, Dongwei Gui, Dong Wang, and Jichun Wu

The Tarim River Basin, China's largest inland river, has been grappling with persistent drought challenges. Over 90% of its water resources originate from the headwaters, heavily relying on groundwater. Existing drought indices often compartmentalize considerations of surface water and groundwater variables. Consequently, there is a necessity for a comprehensive drought index that accounts for the interplay between surface water and groundwater. This study employs the Copula function to formulate the Standardized Precipitation Evapotranspiration Groundwater Index (SPEGI), incorporating surface water (precipitation minus evaporation) and groundwater (changes in total water storage observed by GRACE satellite minus changes in output from the VIC model). SPEGI is computed using a moving average approach across various time scales (1, 3, 6, 12 months) and is juxtaposed with traditional indices such as Standardized Precipitation Evapotranspiration Index (SPEI), Standardized Soil Moisture Index (SSMI), and Standardized Groundwater Index (SGI). The findings underscore that SPEGI, grounded in the integrated consideration of surface and groundwater variables, provides a more comprehensive depiction of drought conditions in the study area. In contrast to traditional indices, SPEGI not only accounts for short-term precipitation and evaporation changes but also effectively reveals the characteristics of groundwater fluctuations. Additionally, by comparing SPEGI with NDVI data, the study delves into the desertification process in the region. The research discerns that SPEGI's assessment of drought resilience is more sensitive, manifesting an increasing trend in the desertification process with the enlargement of SPEGI's sliding window. Overall, this research contributes novel methodologies and empirical evidence for fostering sustainable water resource utilization and informing climate change adaptation decisions within the basin.

How to cite: Yu, X., Zeng, X., Gui, D., Wang, D., and Wu, J.: Exploring Drought Patterns in the Headwaters of the Tarim River Basin through an Integrated Surface-Groundwater Drought Index, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7068, https://doi.org/10.5194/egusphere-egu24-7068, 2024.

12:20–12:30
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EGU24-20616
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On-site presentation
Magna Moura, Rodolfo Nobrega, Anne Verhoef, Josicleda Galvíncio, Rodrigo Miranda, Bruna Alberton, Desiree Marques, Cloves Santos, Bruno Nascimento, Maria Maraiza Pereira, and Patricia Morellato

The Seasonal Tropical Dry Forest (STDF) known as Caatinga occupies approx. 10% of the Brazilian territory. Its vegetation exhibits rapid phenological responses to rainfall resulting in corresponding increases in gross primary productivity and biomass production. Determining the timing of the start and end of the growing season is very important to ecosystem studies and to precisely quantify the carbon balance. Satellite-derived vegetation indices have been widely used to capture the vegetation dynamics in response to fluctuating environmental conditions. However, the spatial and temporal resolution of these indices cannot capture fine vegetation features and phenology metrics in a highly biodiverse and heterogeneous environment such as the Caatinga. On the other hand, phenocameras have been successfully used for this particular purpose for tropical and dry ecosystems. Complementarily, proximal spectral response sensors (SRS) have been used to allow computation of vegetation indices as phenology proxies. Due to their ability to capture high spatial resolution imagery, Unmanned Aerial Systems (UAS) or drones, can deliver an excellent spatial and a very good temporal resolution for diverse detailed vegetation studies. In this context, the objective of this study was to verify whether multi-sensor and multi-platform technologies provide an enhanced assessment of spectral indices and phenological dynamics of the Caatinga. The field campaign occurred in a pristine area of caatinga vegetation, located at the Legal Reserve of Caatinga, Embrapa Semi-Arid, Petrolina, Brazil. Indices for detecting phenology dynamics were obtained using multi-spectral cameras installed on unmanned aerial vehicles (UAV), field spectral response sensors (SRS), phenocameras (digital RGB cameras) and MODIS satellite data (visible and near infrared) from 2020 to 2023. Environmental driving data were measured via instrumentation installed on a flux tower. Standard statistical measures, including correlation coefficients were employed to verify the relationship observed on Normalized Difference Vegetation Index (NDVI), Photochemical Reflectance Index (PRI), and Green Chromatic Coordinate (Gcc) determined by different sensors and platforms. We observed a substantial and fast increase in Gcc, NDVI and PRI immediately after rainfall events. The sensitivity of NDVI and PRI to changes in vegetation can vary depending on factors such as vegetation greenness, overall plant health, and stress responses according to the environmental conditions of the study area. Particularly during the dry season, indices derived from higher spatial resolution sensors consistently showed lower NDVI values compared to those obtained from proximal spectral response sensors (SRS) and drones. Our observations indicate that the representation of vegetation captured by satellites and drones aligns well with the data obtained from phenocamera and proximal SRS platforms. The combination of high temporal resolution provided by SRS and phenocameras resulted in improved and more reliable indices that will be indispensable for evaluating the response of Caatinga vegetation to current and future conditions.

Funding: This study was supported by the São Paulo Research Foundation-FAPESP (grants ##2015/50488-5, #2019/11835-2; #2021/10639-5; #2022/07735-5), the Coordination for the Improvement of Higher Education Personnel - CAPES (Finance Code 001), the National Council for Scientific and Technological Development - CNPq (306563/2022-3).

How to cite: Moura, M., Nobrega, R., Verhoef, A., Galvíncio, J., Miranda, R., Alberton, B., Marques, D., Santos, C., Nascimento, B., Pereira, M. M., and Morellato, P.: Integrating Multi-Sensor and Multi-Platform Technologies for Enhanced Assessment of Spectral Indices and Phenological Dynamics in a Seasonal Tropical Dry Forest, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20616, https://doi.org/10.5194/egusphere-egu24-20616, 2024.

Lunch break
Chairpersons: Andries Jan De Vries, Moshe Armon
14:00–14:05
14:05–14:15
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EGU24-19012
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On-site presentation
Hamza Kunhu Bangalth, Jerry Raj, Udaya Bhaskar Gunturu, and Georgiy Stenchikov

The Middle Eastern Shamal, a prominent north-northwesterly wind, plays a crucial role in the Arabian Peninsula's climate and environment. Originating from the interaction between a semipermanent anticyclone over northern Saudi Arabia and a cyclone over southern Iran, it influences regional climate. The Shamal is essential in transporting dust and pollutants from the Tigris-Euphrates to the Persian Gulf, affecting air quality, health, and travel. Its potential as a renewable energy source also highlights its importance for the region's future energy strategies.

However, understanding the time series of the Shamal wind is a complex task, owing to the intertwined influences of natural climate variability and human-induced climate change. While climate change is a critical factor, natural variability driven by internal climate modes like the Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO), and North Atlantic Oscillation (NAO) also significantly influences these winds. These oscillations, operating over multidecadal scales, alongside the overarching trend of climate change, form a complex web affecting the regional climate. 

This study addresses the challenge of decoupling the impacts of climate change and natural climate variability on the Shamal wind. Our analysis employs Empirical Mode Decomposition (EMD), a relatively new approach that allows us to decouple the influence of various internal climate modes from that of anthropogenic climate change. This method surpasses traditional techniques by avoiding assumptions of linearity and stationarity. The study utilizes ERA5 reanalysis data to analyze summer and winter Shamal winds.

Preliminary findings indicate that internal climate modes like the AMO are equally significant as climate change in influencing Shamal wind in the past. This insight is crucial for more accurate projections and predictions of future Shamal wind behavior, benefiting the Middle East's environmental management, health, and renewable energy sectors.

How to cite: Bangalth, H. K., Raj, J., Gunturu, U. B., and Stenchikov, G.: Decoupling the Influence of Climate Change and Natural Variability on the Middle Eastern Shamal Wind , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19012, https://doi.org/10.5194/egusphere-egu24-19012, 2024.

14:15–14:25
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EGU24-20067
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ECS
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On-site presentation
Jerry Raj, Elsa Mohino Harris, Maria Belen Rodriguez de Fonseca, and Teresa Losada Doval

African easterly waves (AEWs) play a crucial role in the high-frequency variability of West African Monsoon (WAM) precipitation. AEWs are linked to more than 40% of the total Mesoscale Convective Systems (MCSs) in the region and these MCSs contribute approximately 80% of the total annual rainfall over the Sahel. Moreover, around 60% of all Atlantic hurricanes, including 80% of major hurricanes, have their genesis associated with AEWs. The simulation of AEWs poses challenges for General Circulation Models (GCMs), for instance, coarse-resolution models in CMIP5 cannot simulate distinct northern and southern AEW tracks. Additionally, accurately simulating rainfall over West Africa proves to be a challenge for these models due to the involvement of multiscale processes and the influence of complex topography and coastlines. 

The present study investigates the impact of ocean layer thickness on the simulation of African easterly waves (AEWs) using a high-resolution coupled General Circulation Model (GCM). The study employs high-resolution global simulations conducted using the climate model ICON as part of the next Generation Earth System Modeling Systems (nextGEMS) project. Two experiments, each spanning 30 years with a horizontal resolution of 10 km, are conducted. These experiments vary in terms of the thickness of the layers in the upper 20m of the ocean. In one experiment, the upper 20m ocean layers have a thickness of 2m, whereas in the other, it is 10m. The representation of two types of AEWs with periods of 3-5 days and 6-9 days are analyzed in the simulations. There is a notable disparity in the representation of African easterly waves (AEWs) between these two experiments. The simulation with thicker ocean layers exhibits less intense wave activity over the Sahel and equatorial Atlantic for 3-5 day AEWs which is evident in the eddy kinetic energy field. This corresponds to diminished convection and negative precipitation anomalies for 3-5 day AEWs compared to the 2m upper ocean layer thickness simulation. In the case of 6-9 day AEWs, the simulation with thicker ocean layers exhibits intensification of wave activity over northern West Africa.

How to cite: Raj, J., Mohino Harris, E., Rodriguez de Fonseca, M. B., and Losada Doval, T.: Impact Of Ocean Layer Thickness on The Simulation Of African Easterly Waves in High-Resolution Coupled General Circulation Model Simulations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20067, https://doi.org/10.5194/egusphere-egu24-20067, 2024.

14:25–14:35
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EGU24-2567
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ECS
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Highlight
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On-site presentation
Manuel F. Rios Gaona, Katerina Michaelides, and Michael Bliss Singer

Rainfall is one of the most important inputs for applications such as hydrological modelling, water resource allocation, flood/drought analysis, and climatic risk assessments. Currently, there exist numerous (global) products offering rainfall estimates at various spatio-temporal resolutions. Nevertheless, there are still places on Earth where the coverage and/or quality of such products is limited due to sparse ground-control data, thus constraining the robustness of input rainfall for hydrological and climate applications. Located in Eastern Africa, the Horn of Africa (HOA) is a place where climate impacts like droughts and floods frequently inflict a huge toll on the lives and livelihoods of millions residing in subsistence rural communities. For places like this, high resolution rainfall data are fundamental to understanding the availability of water resources, flood hazard, and soil moisture dynamics relevant to crop yields and pasture availability.

Here we introduce GIRHAF (Gridded hIgh-resolution Rainfall for the Horn of AFrica), which is a 20-year rainfall product, with a spatio-temporal resolution of 0.05°×0.05°, every 30 minutes. GIRHAF is based on downscaling CHIMES (Climate Hazards center IMErg with Stations) a pentad operational rainfall product which corrects microwave signals in IMERG (Integrated Multi-satellitE Retrievals for GPM -Global Precipitation Measurement mission-) by in situ rain gauging networks. The goal of this product is to offer the HOA region high-resolution rainfall fields that can support more detailed mechanistic analyses of historical rainfall and can also provide the base dataset required to develop stochastic rainfall models capable of simulating forecasted or projected climate scenarios. It is our aspiration that GIRHAF will enable improved responses to climatic hazards as well as better water resources management in the HOA region, and perhaps to allow people of this region to better prepare to future climate scenarios.

How to cite: Rios Gaona, M. F., Michaelides, K., and Singer, M. B.: GIRHAF (Gridded hIgh-resolution Rainfall for the Horn of AFrica): a new rainfall product for detailed applications in a region beset by climate hazards, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2567, https://doi.org/10.5194/egusphere-egu24-2567, 2024.

Water resource management and vegetation and agricultural impacts
14:35–14:45
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EGU24-20999
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ECS
Soil and rock water dynamics in a semiarid karst savanna undergoing woody plant encroachment
Pedro Leite, Bradford Wilcox, Daniella Rempe, and Logan Schmidt
14:45–14:55
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EGU24-7611
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ECS
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On-site presentation
Fengyu Fu, Shuai Wang, and Xutong Wu

China, with vast dryland areas, has undertaken extensive ecological restoration (ER) projects since the late 1970s. While ER is a crucial means against desertification and land degradation, it must be implemented in a water-sustainable manner to avoid exacerbating the carbon–water trade-off, especially in water-limited drylands. However, there is still limited research on accurately identifying water unsustainable ER regions in China's drylands. Here, we developed a water supply–demand indicator, namely, the water self-sufficiency (WSS), defined as the ratio of water availability to precipitation. With the use of remote sensing and multisource synthesis datasets combined with trend analysis and time series detection, we conducted a spatially explicit assessment of the water sustainability risk of ER in China's drylands over the period from 1987 to 2015. The results showed that 17.15% (6.36 Mha) of ER areas face a negative shift in the WSS (indicating a risk of unsustainability), mainly in Inner Mongolia, Shanxi, and Xinjiang provinces, driven by evapotranspiration. Moreover, 29.34% (10.9 Mha) of the total ER areas, whose area is roughly double that of water unsustainable ER areas, exhibit a potential water shortage with a significant WSS decline (-0.014 yr-1), concentrated in Inner Mongolia, Shaanxi, and Gansu provinces. The reliability of our findings was demonstrated through previous studies at the local scale and an analysis of soil moisture changes. Our findings offer precise identification of water unsustainable ER regions at the grid scale, providing more specific spatial guidance for ER implementation and adaptation in China's drylands.

How to cite: Fu, F., Wang, S., and Wu, X.: Locating unsustainable water supplies for supporting ecological restoration in China's drylands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7611, https://doi.org/10.5194/egusphere-egu24-7611, 2024.

14:55–15:05
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EGU24-19172
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On-site presentation
Claude Doussan, Urcel Kalenga Tshingomba, Nicolas Baghdadi, Fabrice Flamain, Arnaud Chapelet, Guillaume Pouget, and Dominique Courault

Water management poses a pervasive challenge in southern France, exacerbated by increasing summer droughts linked to global warming. Water use during spring and summer increases and gets more variable in term of quantity used for crops. Agricultural water use is highly influenced by the diversity in irrigation practices and technics (sprinkler irrigation, drip irrigation, flooding, etc.) ; and can lead to tensions among water users. It is thus essential to estimate field water use at basin scale, as well as crop water status, in order to further optimize water delivered for irrigation. Advances in remote sensing, particularly with Sentinel 1 (S1) and 2 (S2) data, facilitated the development of soil moisture products (SMP) with improved spatial and temporal resolution to characterize soil water in agricultural plots. These SMP products are accessible through the Theia French public platform and suitable for main crops, with NDVI below 0.75 or surfaces with moderate roughness. These specifications can be met for a variety of crop conditions in the south of France. Yet, the validity of the SMP products under various agricultural plot conditions, considering slope, orientation, roughness, and soil moisture, remains to be assessed over extended time periods. From another point of view, such SMP products do not presently apply to orchards plots, which are however, an essential but overlooked component of water use in irrigation and deserve further examination with S1 and S2 data. The objective of our study is twofold: (i) to test SMP products for field crops in different settings and among years, (ii) to preliminary test if S1 data, combined to S2 data, may be linked to soil moisture in orchard plots. Results reveal for (i) that differences can appear between SMP products and soil moisture in various monitored plots, primarily due to variability within farming systems. Beyond a specific slope and vegetation threshold, the correlation does not improve significantly. For (ii), in orchards plots, using a time smoothing of data, S1 VV-retrodiffusion data and NDVI from S2 seem to correlate with soil moisture measurements, with an RMSE < 0.05 cm3/cm3 and enable detection of irrigation events. This study shows that S1 and S2 data are valuable in estimating soil moisture of agricultural plots, giving however some limits in their use, and gives some hope in their further use for orchards water management.

How to cite: Doussan, C., Kalenga Tshingomba, U., Baghdadi, N., Flamain, F., Chapelet, A., Pouget, G., and Courault, D.: Assessing the possibilities of Sentinel products for qualifying and quantifying soil water status of agricultural systems in southern France , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19172, https://doi.org/10.5194/egusphere-egu24-19172, 2024.

15:05–15:15
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EGU24-1165
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ECS
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On-site presentation
ismail bouizrou, Giulio Castelli, Gonzalo Cabrera, Lorenzo Villani, and Elena Bresci

The Mediterranean region is highly susceptible to the consequences of warming, leading to an increasing of extreme events such as droughts, severe heat waves, and precipitation events. The Messinia watershed (MW) is predominantly characterized by olive cultivation, encompassing approximately 70% of the landscape. These olive orchards constitute a vital component of the Mediterranean ecosystem, playing a crucial role in regional agriculture. The MW is a perfect illustration of a Mediterranean watershed significantly impacted by climate change, as well as soil degradation and a lack of effective land management practices.

In this context, agro-hydrological modelling emerges as a potent tool to address soil degradation and enhance water resource retention within the olive orchards at the watershed scale. To achieve this objective, the SWAT+ agrohydrological model was chosen for a comprehensive assessment of the potential impacts of climate change on water resources and ecosystems in the Messinia region. The adopted modelling approach involved both hard and soft calibration techniques, simulating four sub-watersheds of Messinia by incorporating remote sensing data, including evaporation and soil moisture, for multi-criteria model calibration.

The calibrated model was subsequently employed to assess the potential impacts of climate change on water resources and ecosystems in the Messinia region, utilizing various RCM climate scenarios. Our findings are valuable for addressing soil degradation, as well as for guiding land and water management practices in the Messinian watershed.

 

 

This research was carried out within the SALAM-MED project, funded by the Partnership for Research and Innovation in the Mediterranean Area Programme (PRIMA).

The content of this abstract reflects the views only of the author, and the Commission cannot be held responsible for any use that may be made of the information contained therein.

 

How to cite: bouizrou, I., Castelli, G., Cabrera, G., Villani, L., and Bresci, E.: Agrohydrological modelling approach for assessing the impact of climate change on water resources and land management in the Messinian region, Greece., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1165, https://doi.org/10.5194/egusphere-egu24-1165, 2024.

15:15–15:25
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EGU24-17808
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ECS
|
Virtual presentation
Khaoula Ibba, Salah Er-Raki, Abdelaziz Bouizgaren, and Rachid Hadria

The Mediterranean area is recognized as a hotspot for climate change challenges, with noticeable patterns of rising temperatures and dryness. Olive agroecosystems are particularly affected by the increasing aridity and global climatic changes. Despite being a symbol of the Mediterranean and traditionally grown using rainfed agricultural practices, olive growers have to adapt to cope with higher temperatures, drought, and more frequent severe weather incidents, necessitating their attention and adaptation (Fraga et al., 2020). Moreover, crop production in Morocco heavily relies on irrigation because rainfed cropping has limited productivity (Taheripour et al., 2020). The olive sector is of great importance in Morocco, and there is an urgent need to implement sustainable water management practices. This includes water-saving strategies such as regulated and sustained deficit irrigation (RDI and SDI) to sustain olive production and strengthen the sector's resilience to climate change and water scarcity. These strategies primarily differ in terms of their irrigation timing and the quantity of water applied (Ibba et al., 2023). This study aims to evaluate the effect of two deficit irrigation strategies on productive parameters of the Menara olive cultivar, to serve as a tool for operational irrigation water management and appraise the adaptive responses of this cultivar under conditions of induced drought stress. In pursuit of this aim, an experiment was carried out in an olive orchard over two consecutive years (2021 and 2022), comparing four treatments of regulated deficit irrigation (RDI): T1 (SP 100- NP 70% ETc), T2 (SP 100- NP 60% ETc), T3 (SP 80- NP 70% ETc), T4 (SP 80- NP 60% ETc) and two treatments of sustained deficit irrigation (SDI): T5 (70% ETc) and T6 (60% ETc), with fully irrigated trees T0 (100% ETc). The findings showed that controlled water stress, as applied through regulated deficit irrigation (RDI), did not exert a severe impact on the flowering traits and yield of the Menara olive cultivar. Notably, the RDI strategy, particularly under T4 treatment, allowed for the reduction of supplied water by 20% in sensitive periods (SP) flowering and from the beginning of oil synthesis to harvest and by 40% in the normal period (NP)during pit hardening, respectively, without compromising fruit yield. However, the SDI strategy, characterized by restricted water availability, which reduced total water application under T5 and T6 treatments by 30% and 40% throughout the entire season, led to a decline in the fruit yield by about 50% and resulted in the most significant drop in water productivity, ranging from 19% to 33% compared to the control T0. Furthermore, the findings underscored the adaptability of responses to water stress and elucidated the consequential impact of each irrigation strategy on the performance of Menara olive trees across successive years, particularly the importance of regulated deficit irrigation as a water management strategy and the need to consider its implication on flowering traits and crop yield over successive growing seasons to establish the enduring adaptability of this locally cultivated olive cultivar.

How to cite: Ibba, K., Er-Raki, S., Bouizgaren, A., and Hadria, R.: Sustainable Water Management for Menara Olive Cultivar: Unveiling the Potential of Regulated and Sustained Deficit Irrigation Strategies in Morocco, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17808, https://doi.org/10.5194/egusphere-egu24-17808, 2024.

15:25–15:35
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EGU24-10387
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ECS
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Virtual presentation
Sofyan Sbahi, Naaila Ouazzani, Abdessamed Hejjaj, Abderrahman Lahrouni, and Laila Mandi

The multi-soil-layering (MSL) bioreactor has been considered in the latest research as an
innovative bioreactor for reducing the level of pollutants in wastewater. The efficiency of the
MSL bioreactor towards nitrogen pollution is due to the mineralization of organic nitrogen in
aerobic layers to ammonia, and reactivity of ammonia nitrogen with soil and gravel by its
adsorption into soil layers followed by nitrification and denitrification processes when the
alternating phases of oxygenated/anoxic conditions occurs in the filter. In this study, we have
examined the performance of the MSL bioreactor at different hydraulic loading rates (HLRs)
and predicted the removal rate of nitrogen. To improve the prediction accuracy of the models,
the feature selection technique was performed before conducting the Neural Network model.
The results showed a significant removal (p <0.05) efficiency for five-day biochemical
oxygen demand (BOD 5,  86%), ammonium (NH 4 + , 83%), nitrates (NO 3 − , 81%), total kjeldahl
nitrogen (TKN, 84%), total nitrogen (TN, 84%), orthophosphates (PO 4 3− , 91%), and total
coliforms (TC, 1.62 Log units). However, no significant change was observed in the nitrite
(NO 2 − ) concentration as it is an intermediate nitrogen form. The MSL treatment efficiency
demonstrated a good capacity even when HLR increased from 250 to 4000 L/m 2 /day,
respectively (e.g., between 64% and 86% for BOD 5 ). The HLR was selected as the most
significant (p < 0.05) input variable that contribute to predict the removal rates of nitrogen.
The developed models predict accurately the output variables (R 2  > 0.93) and could help to
investigate the MSL behavior.

How to cite: Sbahi, S., Ouazzani, N., Hejjaj, A., Lahrouni, A., and Mandi, L.: Nitrogen modeling and performance of Multi-Soil-Layering (MSL)bioreactor treating domestic wastewater in rural community, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10387, https://doi.org/10.5194/egusphere-egu24-10387, 2024.

Orals: Thu, 18 Apr | Room 3.16/17

Chairpersons: Yves Tramblay, Kathryn Fitzsimmons
08:30–08:35
08:35–08:45
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EGU24-12194
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ECS
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Virtual presentation
Nadia Ouaadi, Lionel Jarlan, Michel Le Page, Mehrez Zribi, Giovani Paolini, Bouchra Ait Hssaine, Maria Jose Escorihuela, Pascal Fanise, Olivier Merlin, Nicolas Baghdadi, and Aaron Boone

Surface soil moisture (SSM) products at high spatial resolution are increasingly available, either from the disaggregation of coarse-resolution products such as SMAP and SMOS, or from high-resolution radar data such as Sentinel-1. In contrast to coarse resolution products, there is a lack of intercomparison studies of high spatial resolution products, which are more relevant for applications requiring the plot scale. In this context, the objective of this work is the evaluation and intercomparison of three high spatial resolution SSM products on a large database of in situ SSM measurements collected on two different sites in the Urgell region (Catalonia, Spain) in 2021. The satellite SSM products are: i) SSMTheia product at the plot scale derived from a synergy of Sentinel-1 and Sentinel-2 using a machine learning algorithm; ii) SSMρ product at 14 m resolution derived from the Sentinel-1 backscattering coefficient and interferometric coherence using a brute-force algorithm; and iii) SSMSMAP20m product at 20 m resolution obtained from the disaggregation of SMAP using Sentinel-3 and Sentinel-2 data. Evaluation of the three products over the entire database showed that SSMTheia and SSMρ yielded a better estimate than SSMSMAP20m, and SSMρ is slightly better than SSMTheia. In particular, the correlation coefficient is higher than 0.4 for 72%, 40% and 27% of the fields using SSMρ, SSMTheia and SSMSMAP20m, respectively. The lower performance of SSMTheia compared to SSMρ is due to the saturation of SSMTheia at 0.3 m3/m3. The time series analysis shows that SSMSMAP20m is able to detect rainfall events occurring at large scale while irrigation at the plot scale are not caught. This is explained by the use of Sentinel-2 reflectances, which are not linked to surface water status, for the disaggregation of Sentinel-3 land surface temperature. The approach can therefore be improved by using high spatial and temporal resolution thermal data in the perspective of new missions such as TRISHNA and LSTM. Finally, the results show that although reasonable estimates are obtained for annual crops using SSMTheia and SSMρ, poor performance is observed for trees, suggesting the need for better representation of canopy components for tree crops in SSM inversion approaches.

How to cite: Ouaadi, N., Jarlan, L., Le Page, M., Zribi, M., Paolini, G., Ait Hssaine, B., Escorihuela, M. J., Fanise, P., Merlin, O., Baghdadi, N., and Boone, A.: High resolution surface soil moisture microwave products: intercomparison and evaluation over Spain, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12194, https://doi.org/10.5194/egusphere-egu24-12194, 2024.

08:45–08:55
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EGU24-17983
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ECS
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Virtual presentation
Abdelhafid Elallaoui, Pierre-Louis Frison, Saïd Khabba, and Lionel Jarlan

In semi-arid Mediterranean regions, the scarcity and limitations of water resources pose major challenges. These invaluable resources are threatened by various factors such as climate change, population growth, urban expansion, and agricultural intensification. Specifically, agriculture, which consumes approximately 85% of the water in the semi-arid zone of the South Mediterranean region, directly contributes to the depletion of groundwater. To promote rational irrigation management, it becomes imperative to monitor the water status of crops. Remote sensing is a valuable technique allowing for monitoring crop fields in different parts of the electromagnetic spectrum giving complementary information about crop parameters. The main objective of this study is to assess the potential of radar and Infrared Thermal data for monitoring the water status of crops in semi-arid regions. In this context, a radar system was installed in Morocco, in the Chichaoua region, consisting of 6 C-band antennas mounted on a 20-meter tower. These antennas are directed towards a maize field. This system allowed for radar data acquisition in three different polarizations (VV, VH, HH) with a 15-minute time-step over the time period extending from September to December 2021. Additionally, the system is complemented by continuous acquisitions from a Thermal Infrared Radiometer (IRT) at 30-minute intervals. These data are further supplemented by in-situ measurements characterizing crop parameters (state of the cover, soil moisture, evapotranspiration and meteorological variables). The study initially focused on analyzing the diurnal cycle of radar temporal coherence. The results indicated that coherence was highly sensitive to wind-induced movements of scatterers, with minimal coherence when wind speed was highest in the late afternoon. Moreover, coherence was also responsive to vegetation activity, particularly its water content, as the morning coherence drop coincided with the onset of plant activity. Subsequently, the study examined the potential of the relative difference between surface vegetation temperature and air temperature to monitor the water status of crops. The results showed that during a period of imposed water stress, the amplitude of this difference increased. These results open perspectives for monitoring the water status of crops using radar and thermal observations with a high revisit frequency.

How to cite: Elallaoui, A., Frison, P.-L., Khabba, S., and Jarlan, L.: Comparison of C-band radar and infrared thermal data for monitoring corn field in semi-arid area., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17983, https://doi.org/10.5194/egusphere-egu24-17983, 2024.

08:55–09:05
|
EGU24-17049
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ECS
|
Virtual presentation
Zoubair Rafi, Saïd Khabba, Valérie Le Dantec, Patrick Mordelet, Salah Er-Raki, Abdelghani Chehbouni, and Olivier Merlin

Morocco's semi-arid region faces challenges due to limited water resources, necessitating efficient irrigation practices for sustainable agriculture. Precision agriculture, coupled with advanced technologies like the Photochemical Reflectance Index (PRI), holds great potential for optimizing irrigation water usage and enhancing crop productivity in this environment. This abstract provides a comprehensive overview of integrating precision agriculture techniques, PRI, and Net Radiation (Rn) to improve irrigation water efficiency and maximize crop productivity in Morocco's semi-arid zone. The study presents and analyzes an experimental investigation of the PRI signal in a winter wheat field throughout an agricultural season to comprehend its dependence on agro-environmental parameters such as global radiation (Rg) and Rn. Rn directly impacts the energy absorbed by plants, a crucial factor for photosynthesis. Elevated Rn levels generally increase energy availability for photosynthetic processes, resulting in higher chlorophyll fluorescence and PRI values. However, excessive Rn can lead to photoinhibition, damaging the photosynthetic apparatus and reducing photosynthetic efficiency. Understanding the interplay between net radiation, PRI, and photoinhibition is crucial for optimizing agricultural practices. Monitoring and managing net radiation levels allow farmers to ensure that the energy available for photosynthesis remains within the optimal range, minimizing the risk of photoinhibition while maximizing crop productivity. Additionally, the daily water stress index based on PRI (PRIj), developed independently of structural effects related to leaf area index (LAI), showed a coefficient of determination (R2) of 0.74 between PRIj and Rn. This reflects the extent of excessive light stress experienced by the wheat field throughout the experiment. In conclusion, the integration of precision agriculture techniques, specifically PRI, offers a promising approach to enhance irrigation water efficiency in Morocco's semi-arid zone. By employing this innovative tool, farmers can optimize water usage, reduce environmental impacts, and ensure the long-term sustainability of agriculture.

How to cite: Rafi, Z., Khabba, S., Le Dantec, V., Mordelet, P., Er-Raki, S., Chehbouni, A., and Merlin, O.: Potential of the Photochemical Reflectance Index in Understanding Photoinhibition and Improving Irrigation Water Efficiency in the Mediterranean Zone, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17049, https://doi.org/10.5194/egusphere-egu24-17049, 2024.

09:05–09:15
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EGU24-17321
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ECS
|
Virtual presentation
Hamza Barguache, Jamal Ezzahar, Mohamed Hakim Kharrou, Said Khabba, Jamal Elfarkh, Abderrahim Laalyej, Salah Er-Raki, and Abdelghani Chehbouni

Accurately assessing sensible (H) and latent (LE) heat fluxes, along with evapotranspiration, is crucial for comprehending the energy balance at the biosphere-atmosphere interface and enhancing agricultural water management. Although the eddy covariance (EC) method is commonly employed for these measurements, it has limitations in providing spatial representativeness beyond a few hundred meters. Addressing this challenge, optical-microwave scintillometers (OMS) have emerged as a valuable tool, directly measuring kilometer-scale H and LE fluxes. These measurements serve to validate satellite remote sensing products and model simulations, such as the Surface Energy Balance Algorithm for Land (SEBAL). In this study, OMS measurements were utilized to assess the fluxes simulated by the SEBAL model at the Agdal olive orchard near Marrakech city. The results revealed that SEBAL's estimated sensible heat fluxes were 3% higher than those measured by OMS, while latent heat fluxes were approximately 15% lower. Based on these findings, we infer that OMS can effectively validate satellite-driven surface energy balance models, thereby supporting agricultural water management.

How to cite: Barguache, H., Ezzahar, J., Kharrou, M. H., Khabba, S., Elfarkh, J., Laalyej, A., Er-Raki, S., and Chehbouni, A.: Quantifying Olive Tree Evapotranspiration in Semi-Arid Regions through Remote Sensing-Based SEBAL Model: Validation with Optical-Microwave Scintillometer, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17321, https://doi.org/10.5194/egusphere-egu24-17321, 2024.

09:15–09:25
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EGU24-18201
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ECS
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Virtual presentation
Youness Ablila, Abdelhakim Amazirh, Saïd Khabba, El Houssaine Bouras, Mohamed hakim Kharrou, Salah Er-Raki, and Abdelghani Chehbouni

Trees characterized by persistent foliage, like olive trees, serve as indispensable assets in arid and semi-arid regions, exemplified by the Haouz plain in central Morocco. The decline in water resources for irrigation, attributed to climate change and excessive underground water extraction, has led to significant degradation of tree orchards in recent years. Employing remote sensing data, we conducted a spatial analysis of tree degradation from 2013 to 2022 using the supervised classification method. Subsequently, a drying speed index (DS) was computed based on the Normalized Difference Vegetation Index (NDVI) derived from Landsat-8 data, specifically focusing on the identified trees. This DS was then correlated with the Standardized Precipitation Index (SPIn) to elucidate the connection between tree degradation and drought, as indicated by precipitation deficit. The findings reveal a discernible declining trend in trees, with an average decrease in NDVI by 0.02 between 2019 and 2022 compared to the reference period (2013-2019). This decline has impacted an extensive area of 37,550 hectares. Furthermore, the outcomes derived from the analysis of SPI profiles depict a prolonged period of dryness, particularly extreme drought in the past four years, characterized by SPI values consistently below -2. Notably, a high correlation coefficient (R) of -0.87 and -0.88 was observed between DS and SPI9 and SPI12 respectively, emphasizing the strong linkage between drying speed and the duration and intensity of drought. These findings emphasize the reliability of NDVI as an effective tool for precise classification of tree land cover. Additionally, they underscore the significant influence of drought on the degradation of trees in the Haouz plain.

How to cite: Ablila, Y., Amazirh, A., Khabba, S., Bouras, E. H., Kharrou, M. H., Er-Raki, S., and Chehbouni, A.: Analyzing Tree Degradation in the Haouz Plain through Remote Sensing: Assessing the Impact of Drought and Spatial Extent, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18201, https://doi.org/10.5194/egusphere-egu24-18201, 2024.

Hydrological cycle dynamics and irrigation
09:25–09:35
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EGU24-17649
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ECS
|
Virtual presentation
Myriam Benkirane, Abdelhakim Amazirh, El Houssaine Bouras, Adnane Chakir, and Said Khabba

The Mediterranean regions, particularly the Moroccan High Atlas, is exposed to natural risks associated with the hydrological cycle, notably intense precipitation events that trigger sudden floods. This research delves into the subtleties of hydrological dynamics in the High Atlas watersheds, specifically in the Zat watershed, to comprehend the seasonality of precipitation and runoff and elucidate the origins of floods.

The results reveal a strong correlation between observed and simulated hydrographs, affirming the model's capability to capture complex hydrological processes. Evaluation metrics, particularly the Nash coefficient, demonstrate a robust model performance during the calibration phase, ranging from 61.9% to 90%. This attests to the model's ability to reproduce the dynamic nature of hydrological systems in the Moroccan High Atlas.

It is noteworthy that the study identifies the snowmelt process as a significant factor of uncertainty in runoff flooding parameters. The complexities associated with snowmelt, especially in the context of spring precipitation, emerge as a crucial factor influencing uncertainties in the simulated results. This finding underscores the importance of accurately representing snowmelt dynamics in hydrological simulations for regions prone to natural risks.

Moreover, the integration of Probability Distribution Functions and Monte Carlo simulations, coupled with rigorous evaluation metrics, enhances our understanding of calibration parameter uncertainties and validates the model's performance. The identified influence of snowmelt on runoff flooding parameters provides crucial insights for future model improvements and the development of effective mitigation strategies in regions vulnerable to natural risks. This research contributes to advancing hydrological modeling practices in complex terrain.

 

Keywords: Seasonality, Rainfall-Runoff, Floods, Calibration, Monte Carlo simulation, Parameter Uncertainty, Hydrological Modeling, Snowmelt Dynamics, Natural Risks.

How to cite: Benkirane, M., Amazirh, A., Bouras, E. H., Chakir, A., and Khabba, S.: Comprehensive Analysis of Hydrological Dynamics and Uncertainties in the Moroccan High Atlas: A Focus on Seasonal Precipitation, Runoff, and Flood Events, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17649, https://doi.org/10.5194/egusphere-egu24-17649, 2024.

09:35–09:45
|
EGU24-5604
|
Virtual presentation
Anis Chekirbane, Khaoula Khemiri, Constantinos Panagiotou, and Catalin Stefan

Integrating physical models with socio-economic considerations is essential to sufficiently analyze complex hydrological systems and design effective strategies for groundwater management. This integrated approach offers an effective means of detecting links between aquifer properties and groundwater processes. This study aims to assess the impact of human activities and climate changes on groundwater resources. In particular, the final goal is to quantify the spatial distribution of natural groundwater recharge, which is needed to assess the impact of anthropogenic factors on sustainable groundwater management in the Chiba watershed, NE of Tunisia as an example of a stressed hydrosystem.

The proposed methodology is based on the estimation of natural groundwater recharge through hydrological modeling with the use of the SWAT model while considering land use/land cover changes occurring within the study area, coupled with the DPSIR (Drivers-Pressures-States-Impacts-Responses) socio-economic approach for time period 1985-2021. The surveys were constructed and processed based on the probability of occurrence for the degree of satisfaction with arguments related to the DPSIR parameter within the category of the 5-point Likert scale (ranging from level 1 - very low to level 5 - very high), including mean, standard deviation, and the consensus (CnS).
Chiba watershed was selected as a case study since its climate is representative of the Tunisian semi-arid context, and due to the high vulnerability of the existing groundwater systems with respect to human activities.

The hydrological simulations suggest a gradual decrease of 33% in the aquifer's natural recharge over the entire time period. The long-term average value of the annual recharge rate per sub-basin does not exceed 3 mm/year, keeping groundwater recharge levels in the basin relatively low. This observation is mainly attributed to climate change with CnS of 0.6 and over-exploitation of the water sources for irrigation purposes (CnS = 0.62), leading to aquifer depletion and degradation of groundwater-dependent ecosystems (CnS = 0.73). These results suggest that different management practices, such as more conservative water use (CnS = 0.6), long-term monitoring and Managed Aquifer Recharge (MAR) with wastewater (CnS = 0.76), can help rural residents to diversify their economies while preserving these water resources. However, although attempts of MAR have been undertaken, they remain insufficient to counter the pressure on the coastal aquifer, underlining the importance of preserving the fragile semi-arid landscape.

The proposed approach is applicable to other regions having similar climatic and socio-economic conditions. It also demonstrates that pure modeling solutions need to be coupled to the socio-economic approaches to be able to constitute a solid asset for sustainable water resources management of stressed hydro-systems.

 

Acknowledgments

This work is funded by National Funding Agencies from Germany,  Cyprus, Portugal, Spain, and Tunisia under the Partnership for Research and Innovation in the Mediterranean Area (PRIMA) and supported under Horizon 2020 by the European Union’s Framework for Research and Innovation.

How to cite: Chekirbane, A., Khemiri, K., Panagiotou, C., and Stefan, C.: An integrated hydrological modeling approach to assess the natural groundwater recharge trends in a Mediterranean coastal aquifer, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5604, https://doi.org/10.5194/egusphere-egu24-5604, 2024.

09:45–09:55
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EGU24-16291
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ECS
|
Virtual presentation
Kaoutar Oukaddour, Michel Le Page, and Younes Fakir

Extreme weather events have an increasing repercussions on ecosystems in recent years. By comprehending how vegetation responds to climatic extremes, their effects may be mitigated. In a semi-arid Mediterranean region, this study examines the temporal connections of the main triggers of agricultural drought, low precipitation, vegetation growth, thermal stress, and soil water deficit. Drought periods and their characteristics were determined using a revised run theory approach. The Pearson correlations across various spatial scales revealed a moderate to low degree of concordance among the drought indices. This discrepancy can be attributed to the geographical heterogeneity and climatic variations observed among the agrosystems within the basin.

The cross-correlation analysis demonstrated the cascading impacts resulting from reduced precipitation. During drought events, the significant connection between precipitation deficits and vegetation persists for at least one month across most index pairs. This suggests that agricultural drought occurrences can be temporally linked through the selected drought indices. The study unveiled short-, mid-, and long-term effects of precipitation deficiencies on soil moisture, vegetation, and temperature. As anticipated, variables like soil moisture and surface temperature, being more instantaneous, exhibited no lag in response to precipitation. Notably, vegetation anomalies at the monthly time step displayed a two-month lag, indicating a preceding impact of vegetation on precipitation.

Employing the run theory to identify drought events and stages with different thresholds revealed substantial variability in drought characteristics namely the duration, the magnitude magnitude, and the intensity. This variability was notably influenced by the selection of both normality and drought thresholds.

How to cite: Oukaddour, K., Le Page, M., and Fakir, Y.: A New Perspective on Agricultural Drought Periods: A Mediterranean Semi-Arid Context, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16291, https://doi.org/10.5194/egusphere-egu24-16291, 2024.

09:55–10:05
|
EGU24-10078
|
ECS
|
Highlight
|
Virtual presentation
El Houcine El Moussaoui, Aicha Moumni, Said Khabba, and Abderrahman Lahrouni

In Morocco, agriculture accounts for 80-90% of water resources. Available data show that the performance of current irrigation systems remains low to medium, with water losses at plots ranging from 30 to 40%, divided between percolation and evaporation. Gravity irrigation is almost total in the study area, resulting in significant percolation losses. In principle, this percolation contributes mainly to the recharge of the aquifer.

The purpose of this study was to evaluate, by simulation, the impact of irrigation techniques on wheat yield and growth using the generic agro-environmental model SALTMED under the climatic and soil conditions of zone R3, which is an irrigation area located in the region of Sidi Rahal about 40 km east of the city of Marrakech in the plain of Haouz. We started the study by calibrating the model based on two parameters: photosynthetic efficiency and harvest index. After calibration, we compared different irrigation techniques implemented in the model (surface irrigation, sprinkler irrigation, and drip irrigation). Simulation results showed that the drip irrigation technique is the most economical, exhibiting the lowest losses attributed to percolation and soil evaporation. Notably, percolation, a significant contributor to groundwater recharge, measured approximately 255.5 mm/season. In addition, the irrigation practice in the study area appears to be overestimated during the observed season and could be reduced by half, according to SALTMED. When the irrigation dose is halved, the simulated yield (grain and total biomass) decreases by only 1.33%.

How to cite: El Moussaoui, E. H., Moumni, A., Khabba, S., and Lahrouni, A.: Wheat irrigation in Marrakech conditions: A Simulation Study using SALTMED, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10078, https://doi.org/10.5194/egusphere-egu24-10078, 2024.

Posters on site: Thu, 18 Apr, 16:15–18:00 | Hall A

Display time: Thu, 18 Apr 14:00–Thu, 18 Apr 18:00
Chairperson: Andries Jan De Vries
A.1
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EGU24-118
Zaher Mundher Yaseen, Bijay Halder, Mohamed A. Yassin, and Sani I. Abba

Climatic disaster is continuously triggering environmental degradation and thermal diversification over the earth's surface. Global warming and anthropogenic activities are the triggering factors for thermal variation and ecological diversification. Saudi Arabia has also recorded precipitation, temperature, and vegetation dynamics over the past decades. Therefore, monitoring past precipitation, temperature, and vegetation condition information can help to prepare future disaster management plans and awareness strategies. The Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks - Climate Data Record (PERSIANN-CDR) from the Center for Hydrometeorology and Remote Sensing (CHRS) data portal and Moderate Resolution Imaging Spectroradiometer (MODIS) are applied for precipitation, Land Surface Temperature (LST), Enhance Vegetation Index (EVI), and Normalized Difference Vegetation Index (NDVI) from 2003 to 2021 respectively. Yearly mean LST, EVI, NDVI, and precipitation values are calculated through the Google Earth Engine (GEE) cloud computing platform. MODIS-based LST datasets recorded the highest temperatures is 43.02 °C (2003), 45.56 °C (2009), 47.83 °C (2015), and 49.24 °C (2021) respectively. In between nineteen years, the average mean LST increased by 6.22 °C and the most affected areas are Riyadh, Jeddah, Abha, Dammam, and Al Bahah. The mean Precipitation is recorded around 776 mm, 842 mm, 1239 mm, and 1555 mm for the four study periods, while the high precipitation area is Jazan, Asir, Baha, and Makkah provinces. In between nineteen years, 779 mm of precipitation is increasing in Saudi Arabia.  Similarly, the NDVI vegetation indices observed 0.885 (2003), 0.871 (2009), 0.891 (2015), and 0.943 (2021), while EVI observed 0.775 (2003), 0.776 (2009), 0.744 (2015), and 0.847 (2021). The R2 values of the LST and EVI correlation is 0.0239 (2003), 0.0336 (2009), 0.0136 (2015) and 0.0175 (2021) similarly correlation between LST and NDVI is 0.0352 (2003), 0.0265 (2009), 0.0183 (2015) and 0.0161 (2021) respectively. The vegetation indices indicate that the green space is gradually increasing in Saudi Arabia and the highly vegetated lands are Meegowa, An Nibaj, Tabuk, Wadi Al Dawasir, Al Hofuf, and part of Qaryat Al Ulya. This analysis indicates that the temperature is increasing but precipitation and green spaces are increasing because of the groundwater recharge through dam construction, precision agriculture, and planned build-up is helps to prepare Saudi Arabia as a green country. Therefore, more attention to preparing the strategic agricultural plants as well as other vegetation and artificial groundwater recharge can improve the country as a green nation. This analysis might help to prepare future planning, awareness, and disaster management teams to prepare for future disasters and strategic steps for sustainable development.

How to cite: Yaseen, Z. M., Halder, B., Yassin, M. A., and Abba, S. I.: Precipitation, temperature, and vegetation indices analysis for Saudi Arabia region: Feasibility of Google Earth Engine, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-118, https://doi.org/10.5194/egusphere-egu24-118, 2024.

A.2
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EGU24-4462
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ECS
Shewandagn Lemma Tekle and Brunella Bonaccorso

Drought events, worsened by climate change, produce detrimental impacts on freshwater availability especially in arid and semi-arid regions. The situation becomes more critical when these hydrologic extremes combine with land use change mainly caused by anthropogenic factors, such as urbanization, intensive farming, and industrial activities. The present study is designed to investigate the combined impacts of climate and land use changes on the future freshwater  stored in the artificial reservoirs of three adjacent river basins located in the central Sicily (Italy), i.e: Verdura (2 active reservoirs with capacities 9.2 Mmc and 4.19 Mmc), Imera Meridionale (one active reservoir with capacity 15 Mmc), and Platani (one active reservoir with capacity 20.7Mmc), using the Soil and Water Assessment Tool (SWAT) model. The reservoirs are used for irrigation, drinking water supply, and electric power generation. Future climate variables such as rainfall, minimum and maximum temperatures were derived from an ensemble Regional Climate Models for two main representative concentration pathway (RCP) scenarios, such as an intermediate emission scenario (RCP4.5) and a severe emission scenario (RCP8.5). A coupled multi-layer perceptron neural networks and cellular automata (MLP-CA) model was implemented to simulate future land use of the region considering the CORINE land cover in 2000, 2006, 2012, and 2018 as a reference dataset. The future land use is then projected until the mid-century (2048) in a six-year interval using the validated MLP-CA model. The soil data from the European soil data center (EUSDAC) was used as input for the SWAT model. The result indicated that the basins could experience a decrease in inflows to the reservoirs. The separate evaluation of climate change and land use changes indicated that the effect of climate change on streamflow variation is more pronounced than the effect of land use change only. In this study, we introduced new hydrological insights into the region by analyzing the attributions of climate change, land use change, and coupled climate and land use changes on the future freshwater availability which were overlooked in the previous studies. The implementation of the proposed approach can contribute to design environmentally sustainable and climate resilient river basin management strategies.

 

Keywords: MLP-CA, Land use change, Climate change, SWAT, Hydrological modeling, Water availability

How to cite: Tekle, S. L. and Bonaccorso, B.: Modeling the impact of climate and land use changes on future water resources dynamics in central Sicily, Italy, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4462, https://doi.org/10.5194/egusphere-egu24-4462, 2024.

A.3
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EGU24-6984
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ECS
Hongye Liu, Rui Zhang, Gaowen Dai, and Yansheng Gu

To explore the relationship between the global change, westerlies, and central Asian aridity, we report ~1.1 Ma local sedimentary environment changes according to high-resolution gamma ray (GR) from downhole logging, Grain size, magnetic susceptibility (MS), rubidium/strontium (Rb/Sr) ratios and total organic carbon (TOC) of an 800-m core (KT11) from the Kashgar region in the western Tarim Basin, arid zone of China. Four dominant sedimentation types, including lacustrine facies, delta facies, fluvial facies, and aeolian dunes, were identified through lithology and grain size frequency curves. The 1.1 Ma sedimentary successions experienced delta deposits with fluvial and aeolian deposits and lacustrines (1.1-0.6 Ma), alternating fluvial and aeolian facies with the occurrence of deltas and lacustrines (0.6-0.15 Ma), and aeolian facies interbedded with deltas and fluvial facies (0.15 Ma-present). Spectral analyses of the GR, MS, and Rb/Sr data reveal cycles with ~70 m, ~30 m and ~14 m wavelengths. These cycles represent ~100-kyr short-eccentricity, ~40-kyr obliquity and ~20-kyr precession frequencies, respectively and mainly are driven by orbitally forced climate change.

Stepwise drying sedimentary conditions and enhanced desertification indicated by increasing Rb/Sr ratios and proportion of aeolian sands, and decreasing TOC since the past 1.1 Ma, implied intensified westerlies, likely resulted from ice volume expansion and ongoing global cooling according to geological record comparison and simulations during the Last Glacial Maximum compared to preindustrial conditions, which may have controlled the expansion of the permanent deserts in inland Asia. These persistent drying trends and intensified westerly circulation in arid regions during glacial periods after the mid-Pleistocene Transition indicated by larger amplitudes of aeolian sand proportion than prior to 0.6 Ma are similar to those in the interior monsoonal Asia, where the larger-amplitude of median grain size indicated enhanced East Asian Winter monsoon intensity and drier glacials.

How to cite: Liu, H., Zhang, R., Dai, G., and Gu, Y.: Westerly aridity in the western Tarim Basin driven by global cooling since the mid-Pleistocene transition, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6984, https://doi.org/10.5194/egusphere-egu24-6984, 2024.

A.4
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EGU24-9681
Nathalie Folton, Thomas De Fournas, François Colléoni, and Mathieu Tolsa

Intermittent rivers and ephemeral streams represent half of the global river network and span all climates. The intermittent rivers and ephemeral streams is a short-hand term for all flowing water that ceases to flow or that dries up completely at some point in time and/or space They are more frequent in arid and semi-arid areas but are also present in temperate, tropical humid, boreal, and alpine areas, where they are mainly located in headwaters. Their abundance is increasing due to climate change and water withdrawals for human activities.

The objective of this study is to represent the spatio-temporal dynamics of flow intermittence at the reach level in river of the seven sub-catchments of the Maures massif (between 1.5 km² and 70 km²).

First, two hydrological continuous models of varying complexities are performed: GR6J (lumped and conceptual), and SMASH (spatially distributed and conceptual) in terms of temporal calibration/validation, by dissociating dry and wet years, to asses the models’ability to simulate observed drying event over time. The metrics are based on daily flow records observed in the 7 catchments since 1968 to 2023.

In the second part, a regionalization method is tested on the spatially distributed model (SMASH). The HDA-PR approach (Hybrid Data Assimilation and Parameter Regionalization) incorporating learnable regionalization mappings, based on multivariate regressions is used. This approach consist to search for a transfer function that quantitatively relates physical descriptors to conceptual model parameters from multi-gauge discharge in order to produce a regional model.

Flow condition observed from multiple data sources (daily flow time series from gauging stations, phototrap installed along the river network taking daily pictures from 2021-04-01 to 2023-31-12, daily conductivity measurements series from 2021-01-01) are used to validate the ability of the regional model to simulate flow intermittence (prediction of dry events) at river section level.

The distributed modelling approach, with a high-resolution conceptual hydrological modeling at 0.250 km² and coupled with Hybrid Data Assimilation and Parameter Regionalization descriptors shows results highlight the effectiveness of HDA-PR surpassing the performance of a uniform regionalization method with lumped model parameters. However, the results on smallest catchments area are lowest.

The study shows the interest of using daily photos which are a good indication of the hydrogical state of the streams to obtain intermittence data and increasing the spatial coverage of observations in order to validate regional model.

How to cite: Folton, N., De Fournas, T., Colléoni, F., and Tolsa, M.: Modelling the intermittence of watercourses in the small French Mediterranean catchments of the Maures massif (Réal Collobrier ) with the SMASH platform (Spatially distributed Modelling and ASsimilation for Hydrology) , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9681, https://doi.org/10.5194/egusphere-egu24-9681, 2024.

A.5
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EGU24-10210
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ECS
Escalate Dry-hot compounded fires threaten Eurasian drylands
(withdrawn)
Huiqian Yu
A.6
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EGU24-14057
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ECS
Feinan Xu, Weizhen Wang, Chunlin Huang, Jiaojiao Feng, and Jiemin Wang

Observations of kilometer-scale turbulent fluxes of sensible (H) and latent heat (LE) are required for the validation of flux estimate algorithms from satellite remote-sensing data and the development of parameterization schemes in the hydro-meteorological models. Since 2019, two sets of Optical and Microwave scintillometer (OMS) systems have been operated in the Heihe River Basin of northwestern China, one on an alpine grassland of upper reaches, another on an oasis cropland of middle reaches, to measure both the areal H and LE. Combined with the observations of eddy-covariance (EC) and meteorological tower systems in both sites, an improved procedure for OMS data processing is proposed. The newly proposed procedure especially improves the preprocessing of raw scintillation data, properly uses the current probably better Lüdi et al. (2005) method in deriving meteorological structure parameters, and chooses the coefficients of similarity functions by Kooijmans and Hartogensis (2016) in calculating fluxes. Evaluated with the results of rather homogeneous grassland, the area-averaged H and LE over the heterogeneous oasis are then determined. Estimates of H and LE agree reasonably well with those obtained from EC in most cases. However, the most interesting is that LE over the oasis during the early crop growing stages is clearly larger than that of EC; while both agree well during the longer crop grown periods. Footprint analysis shows that, compared with EC, the OMS has clearly larger source area that contains a slight area of orchard and shelterbelts distributed near the light path, leading to larger LE during the early stages of crop growth. The area-averaged evapotranspiration (ET) over the oasis is then analyzed more acceptably, which varies from 3 to 5 mm day-1 depending on meteorological conditions during the 39 days of the crop growing period. These results are used to validate the Penman-Menteith-Leuning Version 2 (PML-V2) scheme.

How to cite: Xu, F., Wang, W., Huang, C., Feng, J., and Wang, J.: Turbulent fluxes at kilometer scale determined by optical-microwave scintillometry in a heterogeneous oasis cropland of the Heihe River Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14057, https://doi.org/10.5194/egusphere-egu24-14057, 2024.

A.7
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EGU24-18295
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ECS
Andries Jan De Vries, Moshe Armon, Klaus Klingmüller, Raphael Portmann, Matthias Röthlisberger, and Daniela I.V. Domeisen

Precipitation-related extremes in drylands expose more than a third of the world population living in these regions to drought and flooding. While weather systems generating precipitation in humid low- and high-latitude regions are widely studied, our understanding of the atmospheric processes governing precipitation formation in arid regions remains fragmented at best. Regional studies have suggested a key role of the extratropical forcing for precipitation in arid regions. Here we quantify the contribution of Rossby wave breaking for precipitation formation in arid regions worldwide. We combine potential vorticity streamers and cutoffs identified from ERA5 as indicators of Rossby wave breaking and use four different precipitation products based on satellite-based estimates, station data, and reanalysis. Rossby wave breaking is significantly associated with up to 80% of annual precipitation and up to 90% of daily precipitation extremes in arid regions equatorward and downstream of the midlatitude storm tracks. The relevance of wave breaking for precipitation increases with increasing land aridity. Contributions of wave breaking to precipitation dominate in the poleward and westward portions of subtropical arid regions during the cool season. In these regions, climate projections for the future suggest a strong precipitation decline, while projections of precipitation extremes are highly uncertain due to the influence of the atmospheric circulation. Thus, our findings emphasize the importance of Rossby wave breaking as an atmospheric driver of precipitation in arid regions with large implications for understanding projections and constraining uncertainties of future precipitation changes in arid regions that are disproportionally at risk of freshwater shortages and flood hazards.

How to cite: De Vries, A. J., Armon, M., Klingmüller, K., Portmann, R., Röthlisberger, M., and Domeisen, D. I. V.: The relevance of Rossby wave breaking for precipitation in the world’s arid regions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18295, https://doi.org/10.5194/egusphere-egu24-18295, 2024.

A.8
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EGU24-19511
Seifeddine Jomaa, Amir Rouhani, Maria Schade, J. Jaime Gómez-Hernández, Antonio Moya Diez, Maroua Oueslati, Anis Guelmami, George P. Karatzas, Emmanouil A Varouchakis, Maria Giovanna Tanda, Pier Paolo Roggero, Salvatore Manfreda, Nashat Hamidan, Yousra Madani, Patrícia Lourenço, Slaheddine Khlifi, Irem Daloglu Cetinkaya, Michael Rode, and Nadim K Copty

The Mediterranean Region is a unique mosaic of different cultures and climates that shape its peoples, natural environment, and species diversity. However, rapid population growth, urbanisation and increased anthropogenic pressures are threatening water quantity, quality, and related ecosystem services. Known as a climate change hotspot, the Mediterranean region is increasingly experiencing intensifying droughts, diminished river flows, and drier soils making water management even more challenging. This situation calls for an urgent need for water management to shift from a mono-sectoral water management approach based on trade-offs, to more balanced multisectoral management that considers the requirement of all stakeholders. This means that sustainable water management requires ensuring that water is stored and shared fairly across all sectors at the basin scale.

The research project OurMED (https://www.ourmed.eu/) is part of the Partnership for Research and Innovation in the Mediterranean Area (PRIMA) Programme supported by the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement No 2222. The project was launched in June 2023 and will continue for three years with a grant of 4.4 million euros to develop a holistic water storage and distribution approach tightly integrated into ecosystem services at the river basin scale.

OurMED builds on the multidisciplinary skills of 15 consortium Partners and comprises universities, NGOs, research centres and SMEs from ten countries with complementary expertise in hydrology, hydrogeology, agronomy, climate change, social sciences, remote sensing, digital twins, ecology, and environmental sciences, among others, making it a truly interdisciplinary project. OurMED includes eight distinct demo sites, representing diverse water-related ecosystem properties of the Mediterranean landscape. These include the catchment areas of Bode (Germany), Agia (Crete, Greece), Konya (Turkey), Mujib (Jordan), Medjerda (Tunisia), Sebou (Morocco), Arborea (Sardinia, Italy), and Júcar (Spain). The Mediterranean basin, as a whole, is considered as an additional regional demo site to ensure replicability and reproducibility of proposed solutions at larger scales. 

OurMED vision combines not only technologically-advanced monitoring, smart modelling and optimization capabilities, but also provides data fusion and integrated digital twin technologies to make optimized solutions readily available for decision making. OurMED concept and its implementation to the different demo sites will be presented and discussed.

How to cite: Jomaa, S., Rouhani, A., Schade, M., Gómez-Hernández, J. J., Moya Diez, A., Oueslati, M., Guelmami, A., Karatzas, G. P., Varouchakis, E. A., Tanda, M. G., Roggero, P. P., Manfreda, S., Hamidan, N., Madani, Y., Lourenço, P., Khlifi, S., Daloglu Cetinkaya, I., Rode, M., and Copty, N. K.: OurMED PRIMA-funded Project: Sustainable Water Storage and Distribution in the Mediterranean, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19511, https://doi.org/10.5194/egusphere-egu24-19511, 2024.

A.9
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EGU24-20356
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ECS
Kanchan Mishra, Kathryn E. Fitzsimmons, and Bharat Choudhary

Lake Balkhash, one of the largest inland lakes in Central Asia, plays a pivotal role in providing water and ecosystem services to approximately 3 million people. However, like many water bodies in dryland regions worldwide, Lake Balkhash's hydrology has been significantly affected by climate change and land cover and land-use shifts driven by population growth and water-intensive economic activities. To manage these vital water resources effectively, monitoring the health of water bodies is essential for effective water resource management, security, and environmental conservation. Turbidity, a water quality indicator, measures the water clarity and represents a broader environmental change, allowing us to assess the water body's health and the extent of anthropogenic impact on the entire catchment. It is a measure of water clarity and serves as a crucial indicator of water health, as it represents the primary mechanism for transporting pollutants, algae, and suspended particles.

The present study investigates the temporal and spatial variability of turbidity in Lake Balkhash. We utilize the normalized difference turbidity index (NDTI) with Landsat satellite data spanning from 1991 to 2022 to map turbidity. We consider various climatic and anthropogenic factors, including precipitation, temperature, wind speed and direction, and water levels in and around the lake.

Our findings reveal an overall declining turbidity trend over interannual and seasonal timescales. The results provide a significant negative correlation between turbidity, temperature, and water levels at both temporal scales. However, no straightforward relationship emerges between turbidity and precipitation or wind variables. Specifically, during spring and summer, turbidity exhibits a strong association with temperature and water levels, while in the fall season, water levels are more closely correlated with turbidity. These results underscore the substantial impact of rising temperatures and fluctuations in water levels on the turbidity dynamics of Lake Balkhash. These findings highlight that the warming climate and alterations in lake hydrology pose significant risks to water quality, indicating that monitoring water health alone may not suffice to mitigate the impacts of climate change and human activities.  

How to cite: Mishra, K., Fitzsimmons, K. E., and Choudhary, B.: Seasonal Water Turbidity Dynamics in Arid Central Asia: A Case Study of Lake Balkhash, Kazakhstan, Under Changing Environmental Conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20356, https://doi.org/10.5194/egusphere-egu24-20356, 2024.

A.10
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EGU24-20398
Juan-de-Dios Gómez-Gómez, Antonio Collados-Lara, David Pulido-Velázquez, Leticia Baena-Ruiz, Jose-David Hidalgo-Hidalgo, Víctor Cruz-Gallegos, Patricia Jimeno-Sáez, Javier Senent-Aparicio, Fernando Delgado-Ramos, and Francisco Rueda-Valdivia

Extreme events, and particularly, droughts are a main concern in Mediterranean basins that will be increased in the future due to climate change (CC), according to the forecasting for the region made by researchers. A novel integrated approach is proposed to analyze operational droughts and their propagation in future CC scenarios at a basin scale. This approach has been applied to the Alto Genil basin (Granada, Spain), an alpine Mediterranean basin with the singularity of having an important snow component in its precipitation regime. The Standardized Precipitation Index (SPI) methodology has been applied to the variable Demand Satisfaction Index (DSI) at a monthly scale to evaluate operational droughts. A conjunctive use model of surface and groundwater resources developed with the code Aquatool has been used to obtain historical and future DSI monthly series. It is an integrated management model that includes all water demands, water resources (surface, groundwater, and their interaction), regulation and distribution infrastructures in the Alto Genil system. The Vega de Granada aquifer is a key element of the water supply system such for agricultural needs as for guarantee the urban supply to the city of Granada. Groundwater flow in this important aquifer has been simulated with a distributed approach defined by an eigenvalue model to integrate it in the management model, and in order to obtain a more detailed analysis of its future evolution. The proposed methodology consists of the sequential application of the following steps: (1) generation of future scenarios for the period 2071-2100 to obtain series of precipitation (P) and temperature (T); (2) application of a chain of models: a rainfall-runoff model (Témez) coupled with a snowmelt model to obtain runoff (Q) series in subbasins of Alto Genil basin, a crop water requirement model (Cropwat) to get agricultural demand series, and an integrated management model (Aquatool) to get historical and future series of DSI; and (3) analysis of operational droughts comparing historical and future series of the Standardized Demand Satisfaction Index (SDSI), which is the application of the SPI methodology to the variable DSI. A cluster analysis of variables P and Q has been made in order to define homogeneous hydroclimatic areas by aggregation of subbasins. It will allow us to perform an analyses of the heterogeneity in  the propagation of droughts.

Aknowledments: This research has been partially supported by the projects: STAGES-IPCC (TED2021-130744B-C21), SIGLO-PRO (PID2021-128021OB-I00), from the Spanish Ministry of Science, Innovation and Universities, RISRYEARTH (Recovery funds), and “Programa Investigo” (NextGenerationEU).

How to cite: Gómez-Gómez, J.-D., Collados-Lara, A., Pulido-Velázquez, D., Baena-Ruiz, L., Hidalgo-Hidalgo, J.-D., Cruz-Gallegos, V., Jimeno-Sáez, P., Senent-Aparicio, J., Delgado-Ramos, F., and Rueda-Valdivia, F.: Analysis of operational droughts in an alpine Mediterranean basin using a conjunctive use model of surface and groundwater resources, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20398, https://doi.org/10.5194/egusphere-egu24-20398, 2024.

Posters virtual: Thu, 18 Apr, 14:00–15:45 | vHall A

Display time: Thu, 18 Apr 08:30–Thu, 18 Apr 18:00
Chairpersons: Lionel Jarlan, Said Khabba
vA.1
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EGU24-765
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ECS
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Alix Fournier and Steven Forman

Water is scarce in the northern Chihuahuan Desert, with ~350 mm/yr precipitation, potential evapotranspiration at 1800mm/yr, and rising mean annual temperatures by >2°C since 1960. The main water resources are the Ogallala, Pecos Valley, Dockum, and Edwards-Trinity Plateau aquifers, with depletion rates of ~1 m/yr. Despite the arid climate, the Monahans and Kermit dune fields host perched water tables 1-10 m below the surface, in up to 40 m of aeolian sand spanning the past ca. 2.6 ma, and isolated from the underlying Pecos Valley Aquifer by a Pliocene/Pleistocene fluvial gravel-rich clay. A 3D model based on borehole lithology shows a topographic inversion with a southwest-trending paleo-slope infilled with aeolian sand. The aeolian stratigraphy and basin modeling indicate progressive infilling by aeolian sand with periods of pluvial lake formation and soil development, with groundwater providing dune field stability for vertical accretion and limiting aeolian erosion. Cores of sediments retrieved from the Monahans and Kermit dune fields were sampled for OSL ages and yielded ages up to 500 ka 20 m below the surface of the dunes, with identified deposition periods between 545-470 ka, 300-260 ka, 70-45 ka and post 16 ka. A set of three monitoring wells equipped with data loggers revealed aquifer recharge of 35-40 cm in the Spring and Fall consistent with regional precipitation variability, and a daily recharge cycle of 3-8 mm potentially linked to plant uptake or gravitational forces. Deuterium and 18O isotopic ratios for the dune field aquifers indicate an evaporative enriched water source compared to the Pecos Valley Aquifer, Pecos River, and Chihuahuan Desert precipitation, consistent with local precipitation. Apparent 14C ages <1360 yr for aquifer waters from the upper 1 m indicate recent meteoric recharge. Older 14C ages of > 1.3 to 2.2 ka for waters ~30 m deep and at the western edge of the aquifer indicate mixing with Holocene recharge waters in a southwest flowing aquifer. In contrast, the Pecos Valley Aquifer yields 14C ages of ca. 0.9 to 40 ka with the youngest ages near the dune fields, which suggests recharge from these perched aquifers.

How to cite: Fournier, A. and Forman, S.: Origin, gradient, and recharge processes of perched aquifers of the Monahans and Kermit dune fields, northern Chihuahuan Desert, Texas, USA , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-765, https://doi.org/10.5194/egusphere-egu24-765, 2024.

vA.2
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EGU24-17560
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ECS
Ahmed Moucha, Lionel Jarlan, Pére Quintana-Segui, Anais Barella-Ortiz, Michel Le Page, Simon Munier, Adnane Chakir, Aaron Boone, Fathallah Sghrer, Jean-christophe Calvet, and Lahoucine Hanich

The utilization of water by various socio-economic sectors has made this resource highly sought after, especially in arid to semi-arid zones where water is already scarce and limited. In this context, effective management of this resource proves to be crucial. Our study aims to: evaluate the performance of the new irrigation module in ISBA, quantify the water balance, and assess the impact of climate change and anthropogenic factors on this resource by the horizon of 2041-2060, utilizing high-resolution futuristic forcings from the study (Moucha et al., 2021). To assess the ISBA model with its new irrigation module, we initially compared observed and predicted fluxes with and without activation of the irrigation module. Subsequently, we compared irrigation water inputs at the ORMVAH-defined irrigated perimeters within the Tensift basin. The results of this evaluation showed that the predictions of latent heat flux (LE) considering all available stations in the basin shifted from -60 W/m² for the model without irrigation to -15 W/m². This indicates that the integration of the new irrigation system into ISBA significantly improves the predictions of latent heat flux (LE) over the period 2004-2014 compared to the regular model. Considering the irrigated perimeters, the study results demonstrated that the model with the integration of the irrigation module was capable of replicating the overall magnitude and seasonality of water quantities provided by ORMVAH despite a positive bias. Exploration of the water balance at the Tensift basin level revealed the ISBA model's ability, equipped with its irrigation module, to describe complex relationships among precipitation, irrigation, evapotranspiration, and drainage. Finally, the assessment of the impact of climate change and vegetation cover for the period 2041-2060, utilizing high-resolution SAFRAN forcings projected to the same horizon (Moucha et al., 2021), revealed an increase in irrigation water needs. These results are of paramount importance in the context of sustainable water resource management in arid and semi-arid regions.

How to cite: Moucha, A., Jarlan, L., Quintana-Segui, P., Barella-Ortiz, A., Le Page, M., Munier, S., Chakir, A., Boone, A., Sghrer, F., Calvet, J., and Hanich, L.: Estimation of Irrigation Water Demand in the Southern Mediterranean Region through Explicit Integration of Irrigation Processes in a Land Surface Model: A Case Study of the Tensift Catchment (Morocco)., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17560, https://doi.org/10.5194/egusphere-egu24-17560, 2024.