This work analyzes the sources, sinks and stores of moisture that originates as Amazonian evapotranspiration (ET) from daily to annual timescales. To do this, we use the Weather Research and Forecast (WRF) regional meteorological model with the added capability of water vapor tracers to track the local evapotranspired moisture. The tracers reveal a strong diurnal cycle of Amazonian water vapor which had not been previously reported. This signal is related to the diurnal cycle of ET, convective precipitation and advected moisture. ET's contribution to atmospheric moisture increases from early morning into the afternoon. Some of this moisture is rained out through convective storms in the early evening. Later in the night and following morning, strong winds associated with the South American Low Level Jet advect moisture downwind. The beating pattern becomes apparent when visualizing the Amazonian water vapor as an animation.

How to cite: Domínguez, F. and Eiras-Barca, J.: Moisture Recycling in the Amazon: a study using WRF with water vapor tracers, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5016, https://doi.org/10.5194/egusphere-egu23-5016, 2023.

The Amazon rainforest is a vital component of the hydrological cycle of South America. Its evapotranspiration is an essential supply of atmospheric moisture for precipitation in more southern regions of the continent. The potential impacts of deforestation on precipitation in these distant regions are yet not fully understood.

The present research project aims at quantifying the deficit of evapotranspiration occurring at the location of deforestation, focusing on the southern part of Amazonia, which has experienced intense deforestation since the 80s. We first use the ORCHIDEE land surface model forced with the reanalysis dataset CRU-JRA to simulate the impacts of an imposed land cover change: from observed states of vegetation cover to a massive extension of croplands. The ORCHIDEE model computes all the components of evapotranspiration, giving, in turn, the expected deficit of atmospheric moisture at the location of the land cover change.

Then, thanks to existing datasets connecting any place on Earth with the area that supplies its moisture through the atmosphere, we link this deficit with downwind locations highly dependent on this upwind evapotranspiration for its precipitation. From there, we draw hypotheses about the potential changes in precipitation amounts and seasonality.

In the project’s second phase, these hypotheses are tested against land-atmosphere coupled simulations produced with the IPSL global climate model, nudged to winds from the ERA5 reanalysis. The model grid is zoomed on the South American continent to better describe the atmospheric transport in the region. The land-atmosphere coupled simulations provide information on the atmospheric feedback induced by the land cover change, confirming or invalidating the hypotheses. Since land cover affects not only water fluxes but also energy fluxes, the coupled model experiments give us insights into the atmospheric processes at stake, the changes in cloudiness and local convection, and the potential shifts in precipitation location or timing.

How to cite: Devenet, C., de Noblet, N., Ottlé, C., Viovy, N., and Chéruy, F.: Modeling the Impacts of Deforestation: local drying of the atmosphere and potential effect on downwind precipitation., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7976, https://doi.org/10.5194/egusphere-egu23-7976, 2023.

Atmospheric water residence time, here defined as time between the original evaporation and the returning of its respective water masses to the land surface as precipitation, is a measure of the speed of the atmospheric hydrological cycle. Traditional analytical methods are generally limited by crude assumptions in the coupling between the land surface and the atmosphere, and hence are not applicable to regions with complex monsoon systems under a changing climate. To this end, we have implemented the age-weighted water tracers into the Weather Research and Forecasting WRF model, namely, WRF-age, to follow the atmospheric water pathways and to derive atmospheric water residence times accordingly. The newly developed, physics-based WRF-age is used to regionally downscale the reanalysis of ERA-Interim and the MPI-ESM Representative Concentration Pathway 8.5 scenario (RCP8.5) simulation for an East Asian monsoon region, i.e., the Poyang Lake basin, for two 10-year slices of historical (1980-1989) and future (2040-2049) times. In comparison to the historical WRF-age simulation, the future 2-meter air temperature rises by 1.3 °C and precipitation decreases by 38% under RCP8.5 on average. In this context, global warming leads to decreased atmospheric residence times of the column-integrated water vapor (from 22 to 13 hours) and column-integrated condensed moisture (from 26 to 14 hours) in the atmosphere over the basin, but slightly increased atmospheric residence times of surface precipitation (from 12 to 15 hours) in agreement with reduced the precipitation amounts. Our findings demonstrate that global warming increases the complexity of regional atmospheric water cycle, especially the associated changes in the residence times of atmospheric water states of matter.

How to cite: Wei, J., Arnault, J., Rummler, T., Fersch, B., Zhang, Z., Olschewski, P., Laux, P., and Kunstmann, H.: WRF with age-weighted water tracers: implementation, application, and new insights into the regionally accelerated atmospheric hydrological cycle under global warming, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12671, https://doi.org/10.5194/egusphere-egu23-12671, 2023.

Afforestation has been regarded as an appropriate way to mitigate climate change and enhance ecosystem services. How afforestation affects the availability of water resources is a hot topic in the science community. Most current studies investigate the impact of afforestation on water resources through offline modeling or observation on a small spatial scale. However, the atmospheric water cycle (AWC) is also an important aspect that can alter the availability of water resources, especially on a large spatial scale. With an investment of about US$54.57 billion, the Chinese government implemented the world’s largest afforestation project, the Grain for Green Program (GFGP), to curb the severe soil erosion over the Loess Plateau (LP) since 1999. Here we focused on this ideal platform, the LP, to explore the impact of large-scale afforestation on the processes related to the atmospheric water cycle. We adopted two different approaches to discern the hydroclimatic effect of the GFGP. This first approach used the reanalysis dataset to compare the hydroclimatic states before (1982–1998) and after (1999–2018) the GFGP. Since the reanalysis dataset cannot separate the impact of climate change and afforestation, this study also applied a regional climate model (the Weather Research & Forecasting Model, WRF) to isolate the net hydroclimatic effect of the GFGP by controlled experiments. In particular, the WRF model was driven by two land surface conditions with/without the implementation of the GFGP. We found both approaches reached similar conclusions. Results show the vegetation coverage fraction over the LP increased by 3.15% decade⁻¹ induced by the GFGP. The climatological precipitation and evapotranspiration (ET) increased by 54.62 and 22.56 mm, respectively, after starting the GFGP in 1999. The large-scale afforestation intensifies the atmospheric water cycle over the LP. In addition, based on the dynamic precipitation recycling model, we also found the precipitation recycling ratio approximately increased by 1%. The GFGP alters the regional circulation by influencing diabatic heating, and moisture convergence, resulting in more moisture being advected from the south boundary, thus more atmospheric moisture was retained in the LP. Additionally, the internal branch of the AWC contributes to about 15% of the increased precipitation, while the contribution of the external branch is about 85%. Moreover, the GFGP remotely affects the water vapor budget in the downwind areas. Our work enriched the current understanding of how afforestation affects the water cycle from a precipitation recycling perspective and can help policy-makers to make science-informed afforestation strategies.

How to cite: Tian, L., Chen, S., Zhang, B., and Pan, B.: Assessing the impact of large-scale afforestation on the atmospheric water cycle of the Loess Plateau in China, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6508, https://doi.org/10.5194/egusphere-egu23-6508, 2023.

Moisture recycling of local water sources through evaporation allows a region to maintain precipitation in the same region. Many studies have shown that deforestation can reduce evaporation and downwind rainfall, and it has been suggested that reforestation conversely increase evaporation and downwind rainfall. Precipitation has been observed to increase over China’s Loess Plateau over the past two decades, coinciding with the start of the Grain for Green project - the largest active revegetation programme attempted in the world. However, the contribution of revegetation to the increase in precipitation is yet unknown. Here, we aim to quantitatively analyze the relationship between revegetation, evaporation, and locally recycled moisture. Based on the ERA5 reanalysis data, we used the modified Water Accounting model-2 layers (WAM-2layers) to track the recycling moisture over the Loess Plateau. Preliminary results indicate that local recycling moisture (Er) accounted for almost one-tenth of the annual precipitation, and seems to have a decreasing trend, which was more evident after 2000. Meanwhile, the contribution of local evaporation to local precipitation appears to decrease during both 1982-1999 and 2000-2015, while the decreasing trend has been slightly amplified after the revegetation. Spatially, Er over the Loess Plateau showed a decreasing trend from southeast to northwest. Significant increasing trend of Er can be identified in the northern part of the plateau during 1982-1999. However, after the implement of the Green for Grain Project, most area over the Loess Plateau showed a decreasing trend, which is significant in the east. Thus, contrary to popular wisdom, the revegetation appears to have led to a decrease in evaporation and subsequent recycling, and the increase in precipitation seems to have other causes. These results are subject to high data uncertainty, and further research is needed to better understand the hydroclimatic effects of revegetation projects under climate change.

How to cite: Cao, M., Wang, W., Wang-Erlandsson, L., and Fetzer, I.: Revegetation impacts on moisture recycling over Loess Plateau in China, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-469, https://doi.org/10.5194/egusphere-egu23-469, 2023.

Research on the protection and preservation of wetlands has traditionally focused on direct human drivers and impacts of climate change occurring in their upstream hydrological basin. However, since precipitation falling in the hydrological basin comprises both oceanic and terrestrial evaporation originating mostly outside of the basin boundaries, upwind land use and hydroclimatic changes affecting this supply of precipitation also need to be assessed. This study assesses the vulnerability of 40 wetlands of international importance to land use and hydroclimatic changes occurring upwind (i.e., in their precipitationsheds). We here use a dataset containing atmospheric moisture flows in combination with evaporation from natural and current vegetation to analyse the impact of extra-basin vegetation changes on the precipitation over the wetland basins. The analysis shows that historical land-use conversion has already caused reduced incoming precipitation into most wetland hydrological basins. The strongest effects are seen in (sub)tropical wetlands in South America, Africa and Asia and especially those located downwind of large agricultural areas. Based on our results and current wetland decline rates, we find that wetland sites in China, India, South America and Sub-Saharan Africa are especially threatened by hydroclimatic and vegetation changes outside of their basins. Additionally, larger basins appear to be more reliant on evaporation from within their basin boundaries than smaller hydrological basins. Using wetland ecosystems as an exemplary case, this study stresses the need to incorporate downwind effects to land-use changes in sustainable ecosystem management approaches. Since the transition from potential natural vegetation to agricultural land is often associated with changes in evaporation, land conversion may affect the resilience of wetland water availability. Following this analysis of the upwind moisture sources of wetland basins, future studies should investigate the potential effect of wetland loss on downwind precipitation patterns.

How to cite: Fahrländer, S. F., Wang-Erlandsson, L., Pranindita, A., Andersen, L. S., and Jaramillo, F.: Upwind land-use change impacts on wetland vulnerability, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13426, https://doi.org/10.5194/egusphere-egu23-13426, 2023.

Water is crucial for human health, food and industrial production, ecosystem services, and climate and weather systems. As a major contributor of renewable freshwater over land, humans have been studying the origin of continental precipitation for nearly a century. From the moisture budget perspective, local evapotranspiration in a vast part of the Earth’s surface is effectively smaller than local precipitation. This entails the role of moisture advection in sustaining continental precipitation. However, previous trajectory-based quantification appeared to underestimate the global “continental precipitation recycling (CPR)” ratio –– that is, the fraction of continental precipitation originating from evapotranspiration. To this end, the present study completed a 40-year (1971-2010) tracking of moisture from continental precipitation using a three-dimensional Lagrangian tracking model and optimized water accounting diagnostics. Our Lagrangian tracking confirms that 62% of continental precipitation stems from evapotranspiration, aligning well with the water budget-based estimates in the literature. Across the globe, non-local terrestrial sources dominate 1˚-scale precipitation in nearly 70% of the land areas, together with the greatest continental moisture feedback in the interior of South America, Africa and Eurasia. Seasonally, the CPR ratio anomalies are markedly different between the mid-to-high latitudes and monsoon regions worldwide, from which two kinds of moisture source-regulated hydroclimate are generalized. For transboundary water governance, perennial source hotspots for continental precipitation are identified, including the biome-rich Amazon and Congo rainforests and other major watersheds within 30˚ equatorward. Leveraging the backward “WaterSip” and the forward “WaterDrip” algorithms, we propose two ubiquitous processes of cascading moisture recycling (CMR) that formulate a cascade of regional water cycles. The watershed-scale CMR metrics quantify the hidden interdependence between the regional water cycles through moisture recycling. Overall, by closing the gap in the estimate of the CPR ratio, this work updates the understanding of the moisture recycling, feedback and cascading characteristics of the continental atmospheric water cycle. The outcome sheds light on the potential vulnerability of local precipitation in response to the modification of non-local land surface fluxes by human activities.

How to cite: Cheng, T. F. and Lu, M.: Updated Understanding of Continental Precipitation Recycling Using Global 3-D Lagrangian Tracking, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1887, https://doi.org/10.5194/egusphere-egu23-1887, 2023.

Atmospheric moisture tracking is a valuable technique for understanding the physical processes that drive (extreme) precipitation and drought in our changing climate. By following where precipitated moisture originally evaporated (backtracking) or where evaporated moisture eventually precipitates (forward tracking) we can gain valuable insights into the connection of large-scale weather systems and hydrometeorological events, land-atmosphere interactions, or the impact of land-use changes on water availability.

The WAM2layers model is an Eulerian moisture tracking code that solves the water balance equation for tagged moisture in gridded model output data. With the increasing resolution of weather and climate models, however, data handling and performance have become serious constraints. Over the past year, we have worked on a new version of WAM2layers (github.com/WAM2layers/WAM2layers), in which we tackle these computational challenges and make a substantial upgrade to the user- and developer-friendliness of the model. The most important changes are summarized below.

Usability: the new version of WAM2layers separates configuration from code. This makes it possible to run many different model simulations without modifying the source code. The model can now be run with a single command, supplying a configuration file as an input argument. It is even possible to use the model without copying the code. Simply install the wam2layers Python package from PyPI.

Modularity: we have made a stricter separation between preprocessing steps, the actual tracking code, and utilities for analysing the results. This is important, for example, for working with multiple datasets. So far, we've worked with ERA5 data. Adding support for other datasets requires no modifications to the tracking code, only a separate preprocessing script.

Documentation: the new version of the model comes with documentation on ReadTheDocs. The documentation includes theory, installation instructions, a complete user guide, and contributing guidelines.

Collaborative development: previous versions of the model were already available on GitHub, but further development often happened offline and without coordination. From the start of this project, we have opened up the development process such that everyone can ask questions, raise issues, and open pull requests. The brand-new documentation includes instructions for anyone willing to contribute. We believe this shift represents a modern perspective on collaborative research practice.

How to cite: Kalverla, P., Benedict, I., van der Ent, R., and Weijenborg, C.: Collaborative moisture tracking with WAM2layers v3, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13859, https://doi.org/10.5194/egusphere-egu23-13859, 2023.

Precipitation (P) and evapotranspiration (ET) play a crucial role in the water cycle and have a significant impact on water resources and the energy balance of the Earth's surface. However, it remains a challenge, in particular on regional scales, to detect changes in hydrological variables and attribute them to anthropogenic or natural influences. Traditional studies that aim to detect or attribute changes in atmospheric variables often consider only a single variable at a time. This makes detecting changes in hydrological variables challenging due to large internal variability, the lack of long-term observational coverage and partly poor mechanistic understanding of land-atmosphere coupling processes in a changing climate.

However, because P and ET are related to various other atmospheric variables, such as temperature, humidity, and sea level pressure, the detection of anthropogenic influences may be conducted in principle within a broader multivariate space. Here, we aim at exploiting multivariate relationships to more robustly detect anthropogenic changes to the hydrological cycle at the regional or up to continental scale. We train statistical models from coupled Earth system models to learn the relationships between relatively well observed variables and more poorly observed ones, like P and ET. We demonstrate that such models can predict and extract patterns of forced change in P and ET, albeit somewhat contingent on the realism of the simulation of the Earth system model. The main advantage is that the method does not rely on sparse observations of P and ET, and instead relies on covariates which are more abundantly and reliably observed.

We demonstrate the effectiveness of this approach in a climate-model-as-truth framework, showing that it can capture a wide range of possible hydrological responses produced by the different climate models. We also apply the statistical model to observations to identify forced changes in P and ET that have already occurred. For example, we see an increase in ET in the northern hemisphere likely induced by a reduction in aerosol emissions. Our results show that this method can infer changes in P and ET that may have taken place, in principle even without the need for direct observations of those variables and can provide constrained projections of future water resources and energy balance.

How to cite: Egli, M., Sippel, S., Humphrey, V., and Knutti, R.: Towards using multi-dimensional structures in climate variables to detect anthropogenic changes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7687, https://doi.org/10.5194/egusphere-egu23-7687, 2023.

ITHACA is a 5-year project that aims to benchmark the terrestrial water cycle intensification. Our goal is to estimate the past range of the hydrological cycle variability, determine the present state of its acceleration, and understand its future impacts on the terrestrial water availability. To achieve this, we combine multi-source data products, stochastic analysis, and process-based hydrological modeling from regional to global scale. Here, we present the preliminary results after the completion of its first year, which come with multiple homogenized datasets of water cycle components, R software packages for data pre-processing and data-driven analyses, and methodological suggestions and insights for the cross-scale quantification of water cycle changes. We also discuss the current challenges and the future steps of the project, highlighting the numerous opportunities for active collaboration.  

How to cite: Markonis, Y., Vargas Godoy, M. R., Blöcher, J., Dutta, R., Pratap, S., Pradhan, R., Kazantsev, A., Bašta, P., Rahmati, A., Sanz i Gil, A., Thakur, V., Abbasizadeh, H., Rakovec, O., Hanel, M., Máca, P., Kumar, R., and Papalexiou, S.: Introducing project ITHACA: Investigation of the Terrestrial HydrologicAl Cycle Acceleration, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12775, https://doi.org/10.5194/egusphere-egu23-12775, 2023.

Finding which factors control the spatial variability of surface runoff is fundamental for assessing regional surface water availability. These controlling factors drive the water balance and vary from physio-climatic catchment attributes to anthropogenic activities. A few studies evaluated these factors in the Contiguous United States on catchments with non-human influence (Abatzoglou & Ficklin, 2017). Yet, a comprehensive analysis of the human influence on surface water availability is still missing.

Here, we employed a parametric Budyko-based framework to assess the long-term runoff sensitivity in the last 30 years of 502 catchments in the Contiguous United States. We linked the Budyko-based framework's landscape parameter with an extensive set of 50 climatic, topographic, anthropogenic, and soil factors that were previously found influential on partitioning precipitation into evapotranspiration and runoff. The catchments belong to the GAGES-II database (Falcone, 2010) and have been grouped in reference and human-impacted basins (urban and agricultural) using the most updated land cover data of 2019. A stepwise multiple linear regression model is developed to find the most significant factors in the partitioning depending on the most extensive human activity on the basin and assess their interactions. Also, we analyzed how anthropogenic activities (e.g., irrigated agriculture, urban settlements) alter the effect of climate variables.

Preliminary results suggest that cultivated land is the second most important factor in explaining runoff variability in agricultural basins, and urban settlements increase the runoff in catchments with a high interannual variability of precipitation.

References

Abatzoglou, J. T., & Ficklin, D. L. (2017). Climatic and physiographic controls of spatial variability in surface water balance over the contiguous United States using the Budyko relationship. Water Resources Research, 53(9), 7630–7643. https://doi.org/10.1002/2017WR020843

Falcone, J. A., Carlisle, D. M., Wolock, D. M., & Meador, M. R. (2010). GAGES: A stream gage database for evaluating natural and altered flow conditions in the conterminous United States. Ecology, 91(2), 621–621. https://doi.org/10.1890/09-0889.1

How to cite: Alonso Vicario, S., Mazzoleni, M., and Garcia, M.: Exploring the human influence on surface water availability in the contiguous United States, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8061, https://doi.org/10.5194/egusphere-egu23-8061, 2023.

Irrigation practice has impacts on the natural environment by changing the water and energy balance at the land surface and thereby interacting with the atmosphere. To quantify such impacts and estimate irrigation water demand, process-based hydrological models with a representation of irrigation practice are often used. However, the applicability of existing irrigation schemes is limited to arid and semi-arid regions. Likewise, it is still lack of more sophisticated irrigation schemes that can be particularly applicable to humid regions. This study presents the newly developed Crop-classified Dynamic Irrigation (CDI) scheme that has been two-way coupled into the land surface-hydrologic model Noah-HMS. Such development allows to distinguish the different irrigation practices for "rice" and "non-rice" crops and to estimate irrigation water demand. We have applied the newly developed model to an important grain and industrial crop production base in southern China, namely, Poyang Lake Basin (PLB), where the sown area of rice accounts for more than 60% of the sown area of all crops. As compared to the widely used, traditional Dynamic Irrigation (DI) scheme, the CDI-incorporated Noah-HMS improves the simulations of water and energy balance over the PLB from 2007 to 2015, especially irrigation water amount simulation. The relative error for irrigation water amount of CDI (DI) is -18.1% (-56.8%). In terms of surface water balance, the inclusion of irrigation practice has larger impacts on the simulated soil moisture (+1.7%) during dry years than that (+0.9%) during wet years, while has larger impacts on the simulated surface runoff (4.6%) in wet years than that (2.4%) in dry years. In terms of surface energy balance, irrigation practice leads to increased latent heat flux by 0.9 W/m² (1.4%), decreased sensible heat flux by 0.5 W/m² (1.3%), decreased ground heat flux by 0.02W/m² (5.0%), and increased net radiation by 0.09 W/m² (0.1%). Such impacts on the surface water and energy balance become more pronouncing at local scale especially over the intensively irrigated areas, for example the Nanchang city region. We conclude that our Crop-classified Dynamic Irrigation scheme is especially beneficial for applications in multiple cropping humid regions. Furthermore, our modeling development has the potential to be further extended into the fully coupled atmospheric-hydrologic modeling systems with a more holistic representation of human activities.

How to cite: Yang, Q., Wei, J., Yang, C., and Yu, Z.: Impacts of Farmland Irrigation on Land Surface Water and Energy Balance over a Humid Region: Development and Benefits of a Crop-Classified Dynamic Irrigation Scheme in Noah-HMS, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4290, https://doi.org/10.5194/egusphere-egu23-4290, 2023.

Evapotranspiration (ET) is the amount of water lost from the global surface, and it represents water and Earth's energy cycle. The intensity and frequency of climate variables have been changed because of the ongoing climate crisis, leading to increased climate disasters, such as heat waves and droughts. The abrupt climate crisis affects the variation of ET because climate variables highly influence ET. However, the future potential ET (PET) estimates include various uncertainty resulted from the variations in the projection of climate variables. In this context, the uncertainty in the projected future PETs should be quantified for the high reliability. Therefore, this study projected future global PET using Penman-Monteith (PM) for the near (2031-2065) and far (2066-2100) futures and quantified the corresponding uncertainty. The six climate variables of 14 CMIP6 GCMs were used for estimating historical PET which were compared to those from the NCEP/NCAR reanalysis data using the five evaluation metrics. The changes in PETs for four Shared Socio-economic Pathways (SSPs) scenarios were calculated for the near and far futures compared to the historical period (1980-2014). Subsequently, the uncertainties of PETs were quantified using the reliability ensemble average method. As a result, the future PET in high latitudes showed the most significant variability compared to the other latitudes. The future PET in the southern hemisphere was higher than the historical PET. Especially the PET in the mid-latitudes of southern hemisphere was the highest among the other latitudes. In addition, the uncertainty of PET was the highest in the high latitudes of the northern hemisphere while the mid-latitude in the northern was the lowest. This study provides insight into evaluating the global water cycle based on PET and helps establish appropriate policies for climate impact assessment.

How to cite: Song, Y. H., Chung, E.-S., Chae, S. T., and Kim, J. H.: Uncertainties in global future projection of potential evapotranspiration using SSP scenarios, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10635, https://doi.org/10.5194/egusphere-egu23-10635, 2023.

Understanding changes in water use efficiency (WUE) and its drivers in terrestrial ecosystems on the Qinghai-Tibet Plateau is important to reveal the response of carbon and water cycle to climate change in the area sensitive to the environment. However, the patterns of carbon and water cycles in different frozen soil zones in this area are not well understood to our knowledge. This study explores the spatial and temporal patterns of WUE, gross primary production (GPP), and evapotranspiration (ET) from 2001 to 2020 at six frozen soil zones (short-time frozen ground; thin seasonally frozen ground; middle-thick seasonally frozen ground; mountain permafrost; predominantly continuous and island permafrost; predominantly continuous permafrost) on the Qinghai-Tibet Plateau with different degrees of freezing based on remote sensing data. The climatic, edaphic, and botanic parameters influencing these patterns were then investigated. The results show that: (1) the WUE, GPP, and ET all generally increased from 2001-2020 for each type of frozen soil ecosystem although the significance and the slope of the trends differed, (2) the WUE and GPP gradually decreased as the degree of freezing increased, while ET first increased and then decreased with the freezing gradient, and (3) enhanced vegetation index was the first important variable influencing WUE for all types of frozen soil regions except for the area of short-time frozen ground. Our results highlight that the freezing degree of soil could influence the evaluation of the water-carbon cycle on the Qinghai-Tibet Plateau.

How to cite: Wang, X., Chen, G., Wu, Q., Cao, L., Awange, J., and Wu, M.: Spatial and temporal patterns and influencing factors of carbon and water cycles in different permafrost types on the Qinghai-Tibet Plateau, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1031, https://doi.org/10.5194/egusphere-egu23-1031, 2023.

Atmospheric moisture transport is a fundamental process in the climate system, critical for the hydrological cycle and water security on land. Moisture exchanges between a basin and its surroundings determine water availability and may change over time due to climate change and other human impacts. Understanding how and why these atmospheric fluxes change under global change is critical for river basins supporting water security in different regions. Here we focused on the Magdalena River basin in northwestern South America, a critical basin for water and energy security in Colombia. We quantified moisture exchanges for the entire watershed and different segments (defined by the boundaries between neighboring basins). We used monthly data between 1979 and 2021 from the ERA5 reanalysis to look for possible changes, including trends. Our results provide new insights into the dynamics of moisture exchanges between the basin and its surroundings. In addition, we found evidence of statistically significant trends likely related to anthropic effects, mainly deforestation and climate change. These results have implications for water security analyses in this region, where there are few studies of this type, and simultaneously generate new insights for decision-making related to water management and transboundary water security in the Magdalena river basin.

How to cite: Giraldo Ramirez, P. A., Molina Santamaria, R. D., and Salazar Villegas, J. F.: Atmospheric moisture exchanges between the Magdalena River basin and its surroundings., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10652, https://doi.org/10.5194/egusphere-egu23-10652, 2023.

The Páramo is a high‐elevation tropical grassland ecosystem that plays an important role in the regional water cycle of Central America and the northern Andes. However, refined information about the ecohydrological partitioning in these mountainous biomes is scarce. This work aimed to assess sub-annual or monthly variations in the ecohydrological conditions along a N-S transect with three Páramo sites: Chirripó (Costa Rica) and El Carmen and Cajas (north and south Ecuador, respectively). A Budyko-type model for conditions under which evapotranspiration surpasses precipitation using monthly meteorological observations and evapotranspiration products (May 2016-April 2019) was applied to evaluate short-term ecohydrological dynamics based on the aridity index and precipitation partitioning in the Páramo sites. Stronger hydroclimatic variations were found in Chirripó than in the Andean Páramos, related with significant increments in the evaporative index (AET/P) during the dry season. We also found a clear separation between Chirripó and the Ecuadorian Páramos owing to a higher ecohydrological resilience (i.e., similar trajectories in the energy excess or 1- AET/PET and the water excess or Q/P) in Chirripó during dry season and a more effective regulation by the additional water available to evapotranspiration besides direct precipitation (y₀, range: 37 – 90 %). Our results reveal the complex ecohydrological functional properties of the Páramo and its sensitivity to future moisture changes (e.g., ENSO cycles) that could alter its water yield synchronicity. 

How to cite: Esquivel-Hernández, G., Sánchez-Murillo, R., Mosquera, G. M., Crespo, P., Célleri, R., Pesantez, J., Lahuatte, B., and Vargas-Salazar, E.: Ecohydrological dynamics in the Central American and Andean Páramo: Insights from a modelling analysis using a Budyko-type model for non-stationary conditions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-965, https://doi.org/10.5194/egusphere-egu23-965, 2023.