The Andes is the longest cordillera in the world and extends from northern South America (11°N) to the southern tip of the continent (∼53°S). The Andes runs through seven countries and provide resources for about 90 million inhabitants. The Andes is characterized by a rich variety of mountain climates and ecosystems, producing unique contrasting climate conditions over its eastern and western sides, but also across its latitudinal extent. Currently, the Andes hydroclimate faces several threats to sustainable development, such as water supply and the sustainability of ecosystem services, including global climate change, Andes and Amazon deforestation and local land use change, glaciers retreat, human encroachment, among others). In turn, diverse hydroclimatic high-impact extreme events affect the Andean communities owing to the prevailing weather and climate patterns, steep terrain, deforestation and human occupancy. This session aims to assess and discuss recent progress in the Andes hydroclimate and identify pressing research challenges and the development of associated human capabilities. We welcome submissions based on observational and modelling approaches, from the local to the continental scales and from diurnal to interdecadal time scales. Emerging new topics are particularly welcome, including water and energy budgets, high impact events, precipitation hotspots, climate change and deforestation impacts, climate-vegetation interactions, cryosphere studies, water resources availability, connections with the Amazon and the La Plata River basins and neighboring oceans, among others.

Public information:
Additional information:
i) This session will be divided into two sub-sessions:
1) Climatology and Atmospheric Sciences, and
2) Hydrology and Water Resources.

The session schedule is available at : (https://meetingorganizer.copernicus.org/EGU2020/sessionAssets/36767/materials.pdf)

ii) Each sub-session will be divided into blocks.
iii) The authors introduce themselves (following the order of the presentations) and provide a couple of sentences summarizing their main result/highlight/discussion topic.
iv) At the end of each block, we dedicate a few minutes to questions from the audience. Each block, including the questions, lasts 10 minutes.
v) We will spend a few minutes on the general discussion and conclusion.

Co-organized by HS13
Convener: Jhan Carlo Espinoza | Co-conveners: Wouter Buytaert, Katja Trachte, Germán Poveda
| Attendance Tue, 05 May, 14:00–15:45 (CEST)

Files for download

Session materials Download all presentations (168MB)

Chat time: Tuesday, 5 May 2020, 14:00–15:45

D3385 |
Jörg Bendix, Oliver Limberger, and Franz Pucha-Cofrep

The tropical mountain forest (TMF) in the Andes of SE-Ecuador is globally one of the hottest hotspots of biodiversity. However, biodiversity and ecosystem services are threatened by environmental changes (climate and land use changes). This particularly holds for the mountain rain forest in the river valley of the Rio San Francisco between Loja and Zamora (Ecuador), where ecosystem water and carbon regulation are important services, expected to be especially affected adversely. An interdisciplinary team of Geo-, Bioscientists and researchers from socio-economy have investigated environmental change impacts on ecosystem water services over the last two decades in this area. Particularly changes in canopy water fluxes due to environmental change are one major objective of the ongoing research unit RESPECT (Environmental changes in biodiversity hotspot ecosystems of South Ecuador: RESPonse and feedback effECTs). In the talk, a general overview on environmental change impacts on canopy water fluxes derived from field measurements such as Eddy Covariance and Remote Sensing are presented. To look into future developments, well-adopted Land Surface Models (LSM) are required including suitable plant functional types (PFTs) and focal ecological processes, properly adapted to the complexity of the TMF. In the second part of the talk, the concept and first results of a new way of LSM modelling will be presented. The integrated concept will be finally used to unveil the resistance of the two ecosystem services against future climate change under different land use scenarios.  

How to cite: Bendix, J., Limberger, O., and Pucha-Cofrep, F.: Environmental change effects on canopy water fluxes of a tropical mountain rain forest in the Andes of Ecuador, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20665, https://doi.org/10.5194/egusphere-egu2020-20665, 2020.

D3386 |
Daniel Martinez, Yamina Silva, Rene Estevan, Jose Luis Flores, Luis Suarez, Aldo Moya, Jairo Valdivia, and Miguel Saavedra

A set of instruments to measure several atmospheric physical, microphysical and radiative properties of the atmosphere and clouds is essential to understand the conditions of formation and development, and eventually, the effects of extreme meteorological events, like severe rainfall, hailstorms and frost events that occur with some regularity in the central Andes of Peru. With this purpose, the Geophysical Institute of Peru has installed a set of specialized sensors in the Huancayo observatory (12.04°S,75.32°W, 3313 m ASL)  including  sub-sets dedicated to the measurements of near-surface and low boundary layer turbulent flows (turbulence and gradients subset),  measurement of precipitation and its structure (precipitation subset)and the measurement of aerosols and their interaction with radiation in the atmosphere (radiation subset). Additionally, a proper open area is reserved for  upper air soundings.  The turbulence subset consists of a set of thermohygrometers (HMP60 probe of Campbell Scientific) placed in two towers, one of 1 m and another of 30 m high, two wind sentry sets (03002 of Campbell Scientific), five tensiometers (Decagon 5TM VWC) to measure soil temperatures and moistures and a soil heat flux plate (HFP01 of Campbell scientific). The radiation subset consists of three pyranometers (CMP10 of Kipp & Zonen), to measure short-wave solar irradiance components, for(global, diffuse and reflected) and a pyrheliometer (CHP1 of Kipp & Zonen) to measure direct solar irradiance. A small black sphere mounted on an articulated shading assembly in a two-axis automatic sun tracker (Kipp & Zonen 2AP) blocked direct solar irradiance and allows to measure diffuse solar irradiance. To measure long-wave terrestrial irradiance components, two pyrgeometers are used (CGR4 of Kipp & Zonen). All these radiative sensors are installed in a tower of 6 m high. The precipitation subset includes A Ka-band cloud profiler (MIRA-35c), a disdrometer (PARSIVEL2) and two rain gauges pluviometers. A UHF wind profiler (CLAIRE), and a VHF wind profiler (BLTR) complement the precipitation subset, as they can detect turbulent low-level wind turbulence, associated with precipitation events.  . The upper-air sounding system consists of two stations: Windsond, for  model S1H3) and Meteo-modem, for model M10 radiosondes. All these sensors have been used to study the surface-atmosphere interactions, including the behavior of surface boundary layer, the components of surface energy budget and the microphysics properties or rainfall during the occurrence of extreme meteorological events, and to validate numerical model simulations. To show practical applications of LAMAR instrumentation we present a detailed analysis of two events: a severe rainfall event occurred on 17 January 2018 and a frost event occurred on 08 July 2018.

How to cite: Martinez, D., Silva, Y., Estevan, R., Flores, J. L., Suarez, L., Moya, A., Valdivia, J., and Saavedra, M.: Laboratory of Atmospheric Microphysics and Radiation (LAMAR): a set of sensors for the study of extreme meteorological events in the Central Andes of Peru., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12664, https://doi.org/10.5194/egusphere-egu2020-12664, 2020.

D3387 |
Cornelia Klein, Wolfgang Gurgiser, and Fabien Maussion

The climate in the Rio Santa basin (Peruvian Andes) is characterized by a strong seasonality, with a wet season reaching its maximum intensity from December to March. Understanding the characteristics and variability of rainfall during the wet season is fundamental for small-scale farmers based on rain-fed agriculture, and is one of the main objectives of the recently started AgroClim-Huaraz project (http://agroclima-huaraz.info). Based on a combination of rain gauge observations and ERA5 reanalysis data, we demonstrate that the occurrence of local wet and dry spells in the Rio Santa basin is strongly connected to large scale circulation patterns that are known to drive such rainfall variability in the wider tropical Andes. Changes in upper-tropospheric zonal wind and the location of the Bolivian High pressure system therefore crucially affect the local water availability. 

On large spatio-temporal scales, this connection was claimed to have already caused a decrease in precipitation in the Central Andes in response to global warming and could be associated with a projected four-fold increase of dry years by 2100. Consequently, it is of great importance to (i) evaluate the validity of this drying by trend analyses from different sources and (ii) understand the implications of a potential large-scale trend from a local perspective that takes into account the heterogeneity of rainfall distributions in complex terrain. 

We therefore use ERA5 to evaluate whether and how observed changes in this teleconnection affect local atmospheric conditions and convective environments. In addition, we infer associated potential trends in rainfall frequency and extremes, cloud cover and convective intensity for the Rio Santa Basin from CHIRPS rainfall estimates and GRIDSAT brightness temperatures down to a resolution of 4-7km for 1983-2019.

Based on observations, our results illustrate how large-scale climatic changes may translate into smaller scales. This will in further steps not only help to validate and constrain regional dynamical downscaling attempts but also inform about the representativeness of coarser-scale climate projections for local conditions in Andean valleys.


How to cite: Klein, C., Gurgiser, W., and Maussion, F.: Observed local drivers of rainfall variability and changes in the Rio Santa Basin, Tropical Andes of Peru, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19981, https://doi.org/10.5194/egusphere-egu2020-19981, 2020.

D3388 |
Julián Villamayor, Myriam Khodri, Beyrem Jebri, Juan A. Rivera, Elizabeth B. Naranjo, and Valérie Daux

The central Andes have undergone a drying trend over the last decades with adverse socioeconomic effects throughout the south of Argentina and Chile. The long-term precipitation variability in this region has been associated with modes of sea surface temperature (SST) and atmospheric circulation variability acting at decadal-to-multidecadal timescales, such as the Interdecadal Pacific Oscillation and the Southern Annular Mode. More recently, the drying long-term trend of precipitation in central Andes has also been linked to a poleward expansion of the Hadley Cell (HC) in the Southern Hemisphere over the last decades. In previous works several possible causes of the HC expansion have been proposed, involving both external forcing (e.g., greenhouse gases and ozone depletion effects) and internal climate variability (e.g., SST and atmospheric modes).

In this work the origin and the causes of the central Andes precipitation variability at decadal-to-longer time scales are studied. For this purpose, the main modes of climate variability that modulate the central Andes precipitation are first identified. Then the changes of these modes and their influence on precipitation are attributed to different factors of external forcing or to internal climate variability. For this analysis large ensembles of different climate simulations and detection-and-attribution experiments performed with the IPSL-CM6A-LR model are used.

How to cite: Villamayor, J., Khodri, M., Jebri, B., Rivera, J. A., Naranjo, E. B., and Daux, V.: Long-term variability of central Andes precipitation in the IPSL-CM6A-LR model: origin and causes., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-14820, https://doi.org/10.5194/egusphere-egu2020-14820, 2020.

D3389 |
Yamina Silva, Daniel Martínez-Castro, Aldo Moya-Álvarez, René Estevan, José Flores Rojas, and Shailendra Kumar

The Mantaro river basin is surrounded by the central Andes of Peru, with altitudes of up to 5300 m.a.s.l. The Mantaro valley, has great economic and social importance for its rich agriculture, as well as water resources, of considerable weight in the generation of power supply electricity and drinking water. This favors the presence of numerous urban centers in the region, highlighting the city of Huancayo with more 500,000 population. The incidence of convective precipitation systems, influenced by the local orographic circulation, in agriculture and social activities in the region is conspicuous, both from the point of view of water supply and as potential weather hazards, in the case of hailstorms and heavy rains, as well as frost event. The project “Strengthening the research line on Atmospheric Physics and Microphysics”  was conceived with the objective of developing a multilateral research on the conditions of formation of precipitation systems in the basin, the dynamical factors influencing their development and the microstructure and phase composition of clouds and precipitation over the valley. The project includes three main components: 1. Characterization of the structure and evolution clouds and precipitation; 2.  Study of the atmospheric aerosol s in the region and their relationship with solar radiation and 3: Development of customized numerical weather forecasting tools focused on different scales and forecast terms, based mainly on the WRF-ARW modeling system. The experimental base of the project was centered in the instrumental complex of the Atmospheric Microphysics and Radiation Laboratory (LAMAR), in the Huancayo Observatory (3300 m.a.s.l), located in the Mantaro Valley. As a result of the project, an atmospheric database with very complete characteristics has been developed, which serves as a test base for the verification of models in different meteorological conditions, including the occurrence of dangerous phenomena.  The project started in April, 2017 and  must finish in April 2020. To date, twelve papers have been published in peer-reviewed journals, on topics such as the study of convective cloud fields and precipitation over South America and Peru from remote satellite sensors, tuning of the configuration of numerical models for the conditions of the central Andes of Peru, numerical weather forecast, study of the structure of convective systems producing  rain in the valley, characteristics of atmospheric aerosols over the valley and the radiative balance. Because of these researches, new numerical modeling tools have been developed for the conditions of the central Peruvian Andes. In this paper we will present the main results from the project, that contributed to increase our understanding of the Andes climate.

How to cite: Silva, Y., Martínez-Castro, D., Moya-Álvarez, A., Estevan, R., Flores Rojas, J., and Kumar, S.: Atmospheric physics and microphysics research project in the Central Peruvian Andes. A multilateral approach., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6534, https://doi.org/10.5194/egusphere-egu2020-6534, 2020.

D3390 |
Christoph Spirig, Gubler Stefanie, Avalos Grinia, Huerta Adrian, Imfeld Noemi, Lavado Waldo, Oria Clara, Quevedo Karim, Rohrer Mario, Scherrer Simon C., Sedlmeier Katrin, and Schwierz Cornelia

In the southern Peruvian Andes, climatic threats such as water scarcity or frost pose major challenges for agriculture. Such events may result in severe yield losses threatening the livelihood of smallholder farmers due to missing adaptive and coping strategies. Knowledge on climate variability and change, on the current state of the climate, as well as short- to midrange predictions potentially improve the farmers’ risk management. However, such knowledge is only partly available and often does not reach rural communities. Climandes, a pilot project of the Global Framework for Climate Services, tackled these shortcomings through the enhancement of climatological observations, the production of gridded datasets using satellite and station observations, the verification of seasonal forecasts to determine their usefulness for small-scale applications, and through the establishment of communication channels and user engagement. This contribution highlights some of the insights from the Climandes project: climatological analyses of spatio-temporal patterns in the southern Peruvian Andes, past trends, as well as the performance of seasonal forecasts in the region. The work focuses on temperature and precipitation using the newly developed gridded datasets, quality controlled observational data, and seasonal forecasts of ECMWF SEAS5.

The results of the climatological analysis let us draw the conclusion that precipitation and minimum temperature patterns are likely related through increased / reduced cloud cover and increased / reduced incoming longwave radiation. Both variables show similar spatial patterns for example in austral spring (SON), namely a pronounced northeast / southwest gradient. Trends, which were derived from the enhanced climatological observation data available since 1964, show a strong increase in maximum temperature of around 0.2°C / decade, while minimum temperatures show only very moderate trends. In addition to the slight decrease of total precipitation in austral spring, i.e., the time of sowing, the strong increase of maximum temperatures further decreases soil water availability and enhances drought risk. With regard to seasonal predictions, we found that especially the performance of precipitation forecasts is only very limited in the southern Peruvian Andes, and mostly does not exceed information from climatology. We conclude that seasonal predictions are not applicable for small-scale applications in the region, whereas they may serve as a beneficial basis to assess climate variability and discuss decision-making based thereon.


How to cite: Spirig, C., Stefanie, G., Grinia, A., Adrian, H., Noemi, I., Waldo, L., Clara, O., Karim, Q., Mario, R., Simon C., S., Katrin, S., and Cornelia, S.: Spatio-temporal temperature and precipitation patterns in the southern Peruvian Andes - insights from the Climandes project, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-14175, https://doi.org/10.5194/egusphere-egu2020-14175, 2020.

D3391 |
Céline Duwig, Gabriela Flores, Marc Descloitres, Yvan Rossier, Lorenzo Spadini, Anatoly Legtchenko, Alvaro Soruco, Jaime Argollo, Mayra Pérez, and Waldo Medinacelli

The population of the semi-arid Bolivian Northern Altiplano depends greatly on groundwater resources, surface water being intermittent and often contaminated by human activities. The aim of this study is to provide a first insight into the hydrogeological structure and groundwater dynamics of the Katari-Lago Menor Basin aquifer located between the Eastern Cordillera and Lake Titicaca, Bolivia. Resistivity profiles combined with geology, borehole lithology, topography as well as additional groundwater level and geochemical measurements, were helpful in resolving the spatial limits of the aquifer, the vertical and lateral continuity of the Quaternary porous geologic media, the shape and position of the bottom of the aquifer (depth to the bedrock, i.e. Tertiary or Devonian Formations), and revealed a general overview of the natural dynamic behaviour of the aquifer at the scale of the Katari and Lago Menor Basin. The quaternary sediments are hydraulically connected and behave as a single regional basin-aquifer. The main groundwater flow system starts in the upper Piedmont (high mountain ranges of the Eastern Cordillera) and follows the topographic Piedmont gradient (NE to SW). Most groundwater recharge results from the infiltration of precipitation and runoff on the high mountain ranges. Indeed, groundwater circulating in the upper and lower Piedmont layers present primarily  facies. In the regions of the lower Piedmont urbanized areas, groundwater presenting  facies, show a noticeable enrichment of sulphate and chloride relating mainly anthropogenic contamination (mining and urban nature). A large portion of the aquifer presents an unconfined behaviour whereas it remains confined below the Ulloma Formation. The thickness of the unconfined portion varies from 50 to 150 meters and that of the confined from 100 to 150 meters. Values of hydraulic conductivity for the unconfined portion range from 1.1×10-4 m s-1 (alluvial fan deposit), 2.5×10-6 m s-1 (fluvioglacial deposits,) to 5.9×10-8 m s-1 (glacial deposits), while for the confined part transmissivity values range around 6.0×10-6  m2 s-1 (paleo-lacustrine deposits).

 This multidisciplinary approach proved to be an appropriate method to derive a consistent picture of the hydrogeological functioning of the Katari-Lago Menor Basin aquifer.

How to cite: Duwig, C., Flores, G., Descloitres, M., Rossier, Y., Spadini, L., Legtchenko, A., Soruco, A., Argollo, J., Pérez, M., and Medinacelli, W.: Functionning of the Katari-Lago Menor Basin aquifer, Lake Titicaca-Bolivia, inferred from geophysical, hydrogeological and geochemical data, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-17775, https://doi.org/10.5194/egusphere-egu2020-17775, 2020.

D3392 |
Harold Llauca, Waldo Lavado, Cristian Montesinos, and Pedro Rau

Surface water resources in Peru are heterogeneously distributed in three drainage areas (Pacific, Titicaca, and Atlantic), and their quantification is relevant for planning in economic activities such as water supply and agriculture. However, their continuous monitoring at national scale becomes difficult due to the low stream gauges density and short streamflow records. The aim of this work is to generate a database of simulated monthly streamflows at a national scale from January 1981 to December 2016, applying the parsimonious GR2M model in a semi-distributed approach, under a parameter regionalization scheme. For this, 3594 sub-basins (~300 km2) located in the three drainage areas were tested. These sub-basins were first grouped in 14 calibration regions based on a sensitivity analysis of the runoff ratio (RR) and runoff variability (RV) indexes derived from the GR2M outputs. The model was forced with monthly gridded-data of precipitation and potential evapotranspiration from the PISCO product (Peruvian Interpolated data of the SENAMHI’s Climatological and hydrological Observations) and was calibrated and validated with 38 stream gauges using the Kling-Gupta (KGE) metric. After the parameter regionalization processes, results showed KGE values from 0.5 to 0.8, and a good representation of the runoff seasonality. This is the first time that a monthly streamflow database (PISCO-HyM_GR2M) is developed at national scale in Peru in the 1981-2016 period. This new product will contribute to the hydrological droughts monitoring in Peru and understand water balance on ungauged basins.

How to cite: Llauca, H., Lavado, W., Montesinos, C., and Rau, P.: Monthly semi-distributed hydrological model at national scale in Peru, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3769, https://doi.org/10.5194/egusphere-egu2020-3769, 2020.

D3393 |
Marco Otto, Mónica Maldonado Fonken, Jan Baiker, and Richard Gibbons

Research in high mountain regions has been intensified over the last decade due to e.g. increased concerns about how climate change might affect those regions containing fragile and often remote ecosystems. Wetlands in high mountain regions belong to a kind of vulnerable ecosystems, which have been studied also in the Andes. We systematically gathered information derived from literature on wetland types within the tropical part of high Andean grasslands and shrublands (above tree line) also known as Páramo (northern part) and Puna (southern part). We applied a keyword search on two major global citation database resulting in 230 records from 1979 until present. Here, we found over a hundred peer-reviewed publications focused on High Andean Wetlands providing information on wetland types and geographic references of their respective study sites. Most studies were conducted within the Puna and were related to peatlands. High Andean Wetlands are often seen as providers for certain ecosystem services (ES). Results indicate that current knowledge is mostly based on short-term studies at single-site scale. Thus, not all ES that are assumed to be related to High Andean Wetlands are sufficiently documented by scientific work. Therefore, we present preliminary results of currently conducted studies addressing ES provided by High Andean Wetlands fostering our knowledge and closing still existing knowledge gaps.

How to cite: Otto, M., Maldonado Fonken, M., Baiker, J., and Gibbons, R.: High Andean Wetlands, climate change and ecosystem services – What do we know?, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19824, https://doi.org/10.5194/egusphere-egu2020-19824, 2020.

D3394 |
Andrew J. Wade, Harvey J.E. Rodda, Nicholas P. Branch, Marcos Bruzzone, Alex Herrera, Francisco Araujo-Feriera, Frank M. Meddens, Douglas A.H. Walsh, and Kevin Lane

The aim of the ACCESS project is to help assess the impact of climate change on socio-economic development in the Peruvian Andes, focused on the Ancash region, and to help identify adaptation strategies. As part of this larger effort, we are aiming to understand how climate change will impact: water availability and quality; farming, lives and livelihoods; and to work with local communities to plan adaptation strategies. The current water supply and demand in two catchments in the Cordillera Blanca and two in the Cordillera Negra is being assessed to understand the background water context in contrasting glaciated and non-glaciated landscapes. Based on detailed surveys of the ancient and modern waterscapes led by South American archaeologists, supplemented by more recent data from hydrological measurement and ethnographic surveys and discussions with local communities, a nuanced picture is emerging of how communities have adapted to past and current climate conditions, and potential solutions are being co-developed with the local communities to maintain and improve livelihoods in situations with low rainfall in the Negra and glacial retreat in the Blanca. Crop water demand during the dry season in the Rio Ancash (114 km2) catchment has been assessed using the CROPWAT model and local climate and crop survey data, and the present-day water supply assessed through the gauging of rivers and irrigation canal flows, and measurement of water quality and isotopes. Preliminary results, for the Rio Ancash, suggest the amount of water available for dry season irrigation on the mid-slopes is approximately 70 mm over the cropped area (57 km2) which appears to be less than the crop water demand, though this estimate may change as more data is processed. Initial climate projections suggestion an increase in water as the glaciers melt until around 2050. The dry season crop water demand and supply beyond 2050 is currently being estimated.

How to cite: Wade, A. J., Rodda, H. J. E., Branch, N. P., Bruzzone, M., Herrera, A., Araujo-Feriera, F., Meddens, F. M., Walsh, D. A. H., and Lane, K.: Future water supply and demand in the Peruvian Andes: assessment and implications, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4869, https://doi.org/10.5194/egusphere-egu2020-4869, 2020.

D3395 |
| solicited
| Highlight
Peter van Oevelen

The importance of high mountain regions for global energy and water exchanges research is paramount and yet at the same time they are one of the lesser understood and under-observed regions in the world. The Global Energy and Water Exchanges (GEWEX) Core Project  as part of the World Climate Research Programme has as one of its foci high mountain regions. In particular, it aims to develop a global network of researchers that work in these regions. The Andean region is of particular interest as it has specific climate and weather related challenges unique to this region. We will present how this new initiative for Regional Hydroclimate Project in the Andes fits in the overall suite of activities of GEWEX, how it relates in particular to other regional hydroclimate projects and how it can contribute to a better understanding of the geophysical processes in high mountain environments.

How to cite: van Oevelen, P.: The GEWEX High Mountain Activities and Its Relevance to the Andean Region, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10304, https://doi.org/10.5194/egusphere-egu2020-10304, 2020.

D3396 |
Joshua Er Addi Iparraguirre Ayala, Jose Úbeda Palenque, Ronald Fernando Concha Niño de Guzmán, Ramón Pellitero Ondicol, Francisco Javier De Marcos García-Blanco, Luzmila Dávila Roller, Pool Vásquez Choque, Jesús Gómez Lopez, and Julia Elizabeth Araujo Reyes

The Equilibrium Line Altitude (ELA, m) is a good indicator for the impact of climate change on tropical glaciers , because it varies in time and space depending on changes in temperature and/or precipitation.The estimation of the ELA and paleoELA using the Area x Altitude Balance Ratio method (AABR; Osmaston, 2005) requires knowing the surface and hypsometry of glaciers or paleoglaciers (Benn et al. 2005) and the Balance Ratio (BR) correct (Rea, 2009).

In the Llanganuco basin (~ 9°3´S; 77°37´W) there are very well preserved moraines near the current glaciers front. These deposits provide information to reconstruct the extent of paleoglaciers since the Little Ice Age (LIA) and deduce some paleo-climatic variables.

The goal of this work has been to reconstruct the paleotemperature (°C) during LIA, deduced from the difference between ELA AABR2016 and paleoELA AABRLIA.

The paleoclimatic reconstruction was carried out in 6 phases: Phase 1) Development of a detailed geomorphological map (scale 1/10,000), in order to  identify glacial landforms (advance moraines and polished rocks) which, due to their geomorphological context, can be considered of LIA, so palaeoglaciers can be delimited. Current glacial extension was done using dry season, high resolution satellite images. Phase 2) Glacial bedrock Reconstruction from glacier surface following the GLABTOP methodology (Linsbauer et al 2009). Phase 3) 3D reconstruction of paleoglacial surface using GLARE tool, based on bed topography and flow lines for each defined paleoglacial (Pellitero et al., 2016). As perfect plasticity model does not reflect the tension generated by the side walls of the valley, form factors were calculated based on the glacier thickness, lateral moraines and the geometry of the valley following the equation proposed by Nye (1952), adjusting the thicknesses generated in the paleoglacial front. Phase 4) Calculation of BR in a reference glacier (Artesonraju; 8° 56’S; 77º38’W), near to the study area, using the product BR = b • z • s, where BR= Balance Ratio; b= mass balance measured in fieldwork 2004-2014 (m); z= average altitude (meters) and s= surface (m2) of each altitude band of the glacier (with intervals of 100 m altitude). A value BR = 2.3 was estimated. Phase 5) Automatic reconstruction of the ELA  AABR2016 and paleoELA AABRLIA using ELA Calculation tool (Pellitero et al. 2015) after 3D reconstruction of the glacial and paleoglacial surface in phases 2 and 3. Phase 6) Estimation of paleotemperature during LIA by solving the equation of Porter et al. (1995): ∆T (°C)= ∆ELA • ATLR, where ∆T= air temperature depression (ºC); ∆ELA = variation of ELA AABR 2016-LIA and ATLR = Air Temperature Lapse Rate, using the average global value of the Earth (0.0065 °C/m), considered valid for tropics.

The results obtained were: ELA AABR2016= 5260m, paleoELA AABRLIA= 5084m, and ∆T = 1.1 °C. The reconstruction of air paleotemperature is consistent with different studies that have estimated values between 1–2 °C colder than the present, with intense rainfall (Matthews & Briffa, 2005; Malone et al., 2015).

How to cite: Iparraguirre Ayala, J. E. A., Úbeda Palenque, J., Concha Niño de Guzmán, R. F., Pellitero Ondicol, R., De Marcos García-Blanco, F. J., Dávila Roller, L., Vásquez Choque, P., Gómez Lopez, J., and Araujo Reyes, J. E.: Paleoclimatic reconstruction during the Little Ice Age in the Llanganuco basin, Cordillera Blanca (Peru), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-1726, https://doi.org/10.5194/egusphere-egu2020-1726, 2020.

D3397 |
Lavado-Casimiro Waldo, Jimenez Juan Carlos, Llauca Harold, Leon Karen, Oria Clara, Llacza Alan, Huerta Adrian, Felipe Oscar, Acuña Julia, Rau Pedro, and Abad Jorge

Hydrological hazards related to flash floods (FF) in Peru have caused many economic and human life losses in recent years. In this context, developing complete early warning systems against FF is necessary to cope impacts. For this purpose, hydrological and hydraulic models coupled to numerical weather models (NWM) that provide forecasts are generally used.

In this sense, the National Meteorological and Hydrological Service of Peru (SENAMHI) has launched the ANDES initiative (Operational Forecasting System for Flash Floods of SENAMHI in English) to support FF events. 

The pilot region is the Vilcanota basin located in the southern Andes into Cusco department. For this purpose, 4 hydrological stations will be monitoring at hourly time resolution (km 105-Intihuatana, Chilca, Pisac and Sallca). More, 3 video cameras in real time will be employed to velocimetry and water levels monitoring. An exhaustive hydrometry analysis (rating curve) will be implemented to follow discharges day by day. The forcing for the hourly hydrological modelling will be the SENAMHI’s automatic stations (rainfall and temperature). For this purpose a merge spatial prediction methodology between satellite real time precipitation and gauge station precipitation will be develop: GPM (Imerg), GSMAP and Hydroestimator satellite products will be evaluated. Preliminary results of hourly hydrological model shown good results using pure satellite precipitation. In the next months an hydraulic model will be implemented in the channels with more flood vulnerability (Lisflood model) that together with an Numerical weather prediction (NWP) the WRF (The Weather Research and Forecasting) meteorological model will be implemented in the Vilcanota basin. The update will be done every six hours and to improve the output results a bias correction methodology  will be use. Finally using these forecasts will be assimilated in the hydrological and hydraulic models.

This research is part of the multidisciplinary collaboration between British and Peruvian scientists (NERC, CONCYTEC).

How to cite: Waldo, L.-C., Juan Carlos, J., Harold, L., Karen, L., Clara, O., Alan, L., Adrian, H., Oscar, F., Julia, A., Pedro, R., and Jorge, A.: ANDES: The first system for flash flood monitoring and forecasting in Peru, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3759, https://doi.org/10.5194/egusphere-egu2020-3759, 2020.

D3398 |
Adrian Huerta, Waldo Lavado, and Pedro Rau

This study provides for the-first-time a water availability analysis at drainage and basin-scale in Peru. Using new gridded datasets of precipitation and temperature, along with six global actual evapotranspiration estimations from remote sensing products, the vulnerability of water resources due to climate change is evaluated. This is addressed under a bottom-up approach and probabilistic Budyko framework that enables us to measure the associated uncertainty. First, to select an adequate estimation of long-term actual evapotranspiration, we compared at basin-scale the remote sensing products with long-term actual evapotranspiration inferred from a water-balance (precipitation minus discharge) and deterministic Budyko (aridity and evaporative index relationship). Later, the probabilistic Budyko is calibrated using the adequated remote-sensed actual evapotranspiration and is cross-validated at country, drainage, and basin-scale. Finally, the water availability vulnerability (measured as the relative change of precipitation minus actual evapotranspiration from historical estimates) and associated uncertainty is computed from the probabilistic Budyko along with climate spaces from variations of potential evapotranspiration (from temperature) and precipitation. The main results show that GLEAM, MEAN, and TerraClimate are the highest-ranked products in terms of estimation of long-term mean actual evapotranspiration across basins with low bias, RMSE, and high R. GLEAM and MEAN present lower bias and RMSE, and TerraClimate estimate very well the spatial distribution of actual evapotranspiration (highest-ranked R). On the contrary, Zhang, MODIS16, and SSEBop are less efficient based on most criteria evaluation. Therefore, as reference for actual evapotranspiration, we select MEAN which represents the linear averaging of remotely sensed products. From this perspective, we expect to minimize the negative bias and preserve the spatial resolution from individual actual evapotranspiration products. Achieved the three main long-term variables, we calibrate and cross-validate the probabilistic Budyko in terms of the evaporative index. The evidence suggests that the regional distribution of the Budyko parameter accomplishes errors of +-2% at the country and drainage-scale and +-9% as average at basin-scale. Thus, the probabilistic Budyko framework provides great performance. Based on this evaluation, we figure out that basins located in the Andes, especially in the southern, showed lower critical precipitation change (less than 10%) to increase the vulnerability of water availability by 25%.

This research is part of the multidisciplinary collaboration between British and Peruvian scientists (NERC, COCYTEC).

How to cite: Huerta, A., Lavado, W., and Rau, P.: The vulnerability of water availability in Peru due to climate change: A probabilistic Budyko analysis, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3766, https://doi.org/10.5194/egusphere-egu2020-3766, 2020.

D3399 |
Andres Goyburo, Pedro Rau, Waldo Lavado, Fabian Drenkhan, and Wouter Buytaert

This research assesses present (2009-2016) and future (until 2100) levels of water security taking into consideration socioeconomic and climate change scenarios using the WEAP (Water Evaluation and Planning) tool for semidistributed hydrological modeling. The study area covers the  Vilcanota-Urubamba basin in the southern Peruvian Andes and presents a complex water demand context as a glacier-fed system.

Current total water demand is estimated in 5.12E+9 m3/year and includes agriculture (6674.17 m3/year), domestic (7.79E+07m3/year), industrial (1.01E+06 m3/year) and energy (5.03e+9 m3/year) consumption. For assessing the current water supply, observed flow data is used to simulate and validate the model (also accounting for glacier melt contribution). The analysis of unmet water demand for the period 2016–2100 was computed using the soil moisture scheme of the WEAP model, which simulates the hydrological cycle and generates future scenarios for water demand. Different scenarios were generated for external driving factors (population growth and increasing agriculture area) and the impact of climate change to evaluate their effect on the current water supply system. 

These results will allow for the first time to evaluate the impact of changes in glacier melt contributions on water security taking into account also changes in water demand.

This study also further explores the importance of incorporating science and policy within a broader study of water security. As a result, it is expected to deliver high spatial resolution water demand maps and adaptation strategies for stakeholders. This research is part of the RAHU project as a new multidisciplinary collaboration between UK and Peruvian scientists.

How to cite: Goyburo, A., Rau, P., Lavado, W., Drenkhan, F., and Buytaert, W.: Present and future water security under socioeconomic and climate changes in the Vilcanota-Urubamba basin, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5306, https://doi.org/10.5194/egusphere-egu2020-5306, 2020.

D3400 |
Hans Segura, Jhan Carlo Espinoza, Clementine Junquas, Thierry Lebel, Mathias Vuille, Jean-Emmanuel Sicart, and Thomas Condom

During the austral winter (June-August, JJA), precipitation events in the Altiplano (20°S-15°S, > 3000 m.a.s.l.) are uncommon. These events are responsible for damaging road infrastructure and devastating entire crop fields, loss of cattle, and even for the loss of human lives. Thus, an analysis of these events and the understanding of their precursory atmospheric mechanisms are of high importance to diminish their negative impacts. In this study, using 90 rain-gauge stations in the northern Altiplano, we identified days with a precipitation value above the percentile 90 (P90) for the 1979-2014 period. These days were considered as extreme precipitation events. If consecutive single events are separated by a gap of 5 days, we decided to consider those as a new single event. Thus, it was cataloged 129 extreme precipitation events over the northern Altiplano. Moreover, we found that 56 events lasted only for one day (EV1), 28 events for 2 days (EV2), and 45 events for at least 3 days and a maximum of 12 days (EV3). In order to understand the atmospheric mechanisms associated with these extreme events, we used the K-means cluster analysis in the geopotential height at 500 hPa (ERA-Interim) for days inside EV1, EV2 and EV3, respectively. Then, composite analyses of atmospheric circulation at 850, 500 and 200 hPa were done for each cluster group. We observe that two cluster groups in EV1, EV2, and EV3, respectively (98 events in total), are characterized by anomalies of winds, temperature and geopotential height resembling a cutoff low system over the eastern Pacific between 30°S-10°S at 200 and 500 hPa. Over South America, we observed that these events are also associated with southerly cold air intrusions arriving at 20°S and a moistened lower troposphere over the western Amazon. Indeed, the lower troposphere moistening over the western Amazon in previous days seems to be necessary to sustain long-lasting events. One cluster group in EV1 (8 events) and EV2 (6 events), respectively, is associated with southerly cold air intrusions to the east of the Andes originating at high latitudes, and arriving in equatorial regions. In addition, 17 events belonging to EV3 are associated with an anomalous South American Low-Level Jet at 850 hPa and atmospheric anomalies at 200, 500 and 850 hPa, resembling the cutoff low system over the eastern Pacific between 30°S and 10°S.

How to cite: Segura, H., Espinoza, J. C., Junquas, C., Lebel, T., Vuille, M., Sicart, J.-E., and Condom, T.: Atmospheric mechanisms controlling extreme winter precipitation in the Altiplano, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5353, https://doi.org/10.5194/egusphere-egu2020-5353, 2020.

D3401 |
Gabriela Urgiles, Johanna Orellana-Alvear, Katja Trachte, Jörg Bendix, and Rolando Célleri

Information on the vertical profile of rainfall is important to improve our knowledge about microphysical processes that govern the formation of the hydrometeors. In addition, the vertical profile helps improving the quantitative precipitation estimation from scanning weather radars and may be useful to improve the parameterization of cloud microphysical processes in numerical models. Usually, rainfall types (e.g, stratiform and convective) are defined by using some rainfall characteristics of its vertical profile such as intensity and velocity. Furthermore, certain thresholds for these variables need to be defined to separate the rainfall classes. However, studies about the vertical profile of rainfall showed that the vertical variability of rainfall highly depends on the local climate and the study area. In consequence, these thresholds are a constraining factor for the rainfall class definitions because they cannot be generalized. Besides, the identification of thresholds can become too subjective and, thus, influence the identification of rainfall types. In regions of complex topography such as the Tropical Andes, rainfall vertical profile studies are very scarce and they show that rainfall classification has similar drawbacks such as the identification of thresholds. Thus, this study aims to develop a new methodology for rainfall events classification by using a data-driven clustering approach based on the k-means algorithm that allows accounting for the similarities of rainfall characteristics (e.g., duration, intensity, drop size distribution) of each rainfall type. The study was carried out using data retrieved from a K-band Doppler Micro Rain Radar (MRR) that records rainfall characteristics such as rainfall intensity, drop velocity, reflectivity profile, drop size distribution (DSD), and liquid water content (LWC). The MRR was located in the tropical Andes, at 2600 m a.s.l., in the city of Cuenca, Ecuador.  Three years of data were available for the study with a temporal resolution of 1 minute.  First, the rainfall events were identified by using three criteria: minimum inter-event, minimum total accumulation, and minimum duration. Then, by using the k-means approach, several iterations with different number of clusters each were evaluated and consequently, three representative rainfall classes were found. These classes showed certain transitions (e.g., for rainfall intensity, velocity and drop size distribution) that separated the rainfall classes. The distributions of these rainfall event characteristics were compared with those found in the literature. This novel classification provided new insights about the variability of the rainfall in this tropical mountain setting and how its characteristics revealed distinctive patterns of the rainfall processes. Finally, since the rain types were identified by a data-driven method, it ensured an objective separation of the rainfall events. Thus, the application of this method in other sites will allow contrasting previous findings regarding the suitability of the tailor-used thresholds for rainfall classification.

How to cite: Urgiles, G., Orellana-Alvear, J., Trachte, K., Bendix, J., and Célleri, R.: A novel classification rainfall type using a clustering approach in the tropical Andes., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6238, https://doi.org/10.5194/egusphere-egu2020-6238, 2020.

D3402 |
Clementine Junquas, Maria Belen Heredia, Thomas Condom, Jhan Carlo Espinoza, Jean Carlos Ruiz, and Antoine Rabatel

In the tropical Andes, the evolution of the mass balance of glaciers is strongly controlled by the variability of precipitation and humidity transport. It is therefore crucial to better understand the main patterns of precipitation in terms of spatio-temporal distribution at the local scale. In this study, we focus on the region of the Antizana ice cap, located in the Equatorial Andes about 50 km east of the city of Quito (Ecuador). In addition, the Antizana region is located in a very complex zonal climate gradient, with the Pacific Ocean to the west and the humid Amazonian plains to the east, including an area of ​​maximum precipitation on the Amazonian slope, also called "Precipitation hotspot".

In this study, we perform dynamical downscaling using a Regional Climate Model (RCM) to improve the understanding of the atmospheric processes controlling the spatio-temporal variability of precipitation. The WRF (Weather Research and Forecasting) model is used to perform a set of ten experiments with four one-way nesting domains (27km, 9km, 3km, 1km), with the highest resolution domain centered on the Antizana mountain, for the year 2005. For the model validation, we use the 3B42 satellite product of the Tropical Rainfall Measuring Mission (TRMM) at 3-hourly time step, the ORE Antizana meteorological station (SNO GLACIOCLIM, LMI GREATICE) at hourly time step, and 2 meteorological in-situ stations, installed by the Instituto Nacional de Metereología e Hidrologia (INAMHI) in the Antizana region, with a complete chronology of daily precipitation (mm/day) during the 2005 year.

We test different forcings of DEM (Digital Elevation Model), microphysic schemes, Cumulus schemes and convection-permitting simulation, and radiation/slope dependent options. The analysis focuses in particular on how the different representation of thermally driven valley wind circulation can affect the diurnal cycle of precipitation at the ORE Antizana in-situ station. The influence of the diurnal cycle of the regional humidity flux on the mountain precipitation is also analyzed.

How to cite: Junquas, C., Heredia, M. B., Condom, T., Espinoza, J. C., Ruiz, J. C., and Rabatel, A.: Precipitation diurnal cycle and associated valley wind circulations over an Andean glacier region (Antizana, Ecuador) , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9129, https://doi.org/10.5194/egusphere-egu2020-9129, 2020.

D3403 |
Fiorella Vega-Jacome, Carlos Fernandez-Palomino, and Waldo Lavado-Casimiro

Droughts in Peru are one of the disasters with major losses in economic activities as agriculture or energy production, affecting livelihoods of the population. The occurrence of droughts can be explained by climatic variability of precipitation, where El Niño Southern Oscillation (ENSO) seems to have an important influence. For the first time, this study addresses the spatio-temporal variability, characteristics and trends of droughts in Peruvian Andes for the 1970-2018 period. The regionalization of droughts was performed combining Principal Component Analysis (PCA) and Cluster method, for which the Standardized Precipitation Index (SPI) was used. Finally, a characterization using a trend analysis, correlation with oceanic-atmospheric indices and a drought risk assessment during El Niño Southern Oscillation (ENSO) was performed.

 We found that the spatio-temporal variability of droughts could be best investigated by distinguishing eight homogeneous regions with different regional drought characteristics. Thus, the trend analysis indicates a reduced duration and severity of droughts in the northern Pacific divide and a lower intensity in the south. In addition, the depicted trends seem to indicate increasing droughts in the Altiplano (high plateau) divide. Additionally, considering a decadal analysis of droughts (1970-2010), the number of drought months in the last decade (2000-2010) has reduced in all regions compared to previous decades.

From the drought risk assessment during ENSO, only remarkable results were obtained using the Oceanic Niño Index (ONI). Thus, under positive anomalies of ONI, an increasing risk of droughts was identified in the southern part of the Pacific divide, in the divide of Titicaca and in the south and north of the Amazon divide.

How to cite: Vega-Jacome, F., Fernandez-Palomino, C., and Lavado-Casimiro, W.: Spatio-temporal variability of droughts in Peruvian Andes and associated risks related to ENSO, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11037, https://doi.org/10.5194/egusphere-egu2020-11037, 2020.

D3404 |
Pedro Rau, Wouter Buytaert, Fabian Drenkhan, Waldo Lavado, Juan Jimenez, Nilton Montoya, Vivien Bonnesoeur, Gustavo Valdivia, Walescka Cachay, Andres Goyburo, Eber Risco, Jorge Abad, Jon Mackay, David Hannah, Nicholas Barrand, Martin Siegert, Briggitte Macera, Marcelo Bueno, Carlos Baca, and Cecilia Gianella

The Peruvian Andes are a hotspot of vulnerabilities to impacts in water resources due to the propensity for water stress, the highly unpredictable weather, the sensitivity of glaciers, and the socio-economic vulnerability of its population. In this context, we selected the Vilcanota-Urubamba catchment in Southern Peru for addressing these challenges aiming at our objectives within a particular hydrological high-mountain context in the tropical Andes: a) Develop a fully-distributed, physically-based glacier surface energy balance model that allows for a realistic representation of glacier dynamics in glacier melt projections; b) Design and implement a glacio-hydrological monitoring and data collection approach to quantify non-glacial contributions to water resources and the impact of catchments interventions; c) Mapping of human water use at high spatiotemporal resolution and determining current and future levels of water (in)security; and d) Integrate last objectives in a glacier - water security assessment model and evaluate the tool's capacity to support locally embedded climate change adaptation strategies. 

The RAHU project intends to transform the scientific understanding of the impact of glacier shrinkage on water security and, at the same time, to connect to and inform policy practices in Peru. It follows a "source to tap" paradigm, in which is planned to deliver a comprehensive and fully integrated water resources vulnerability assessment framework for glacier-fed basins, comprising state-of-the-art glaciology, hydrology, water demand characterisation, and water security assessment. It includes glacio-hydrological and water resources monitoring campaigns, to complement existing monitoring efforts of our project partners and collaborators, and new remotely sensed data sets. Those campaigns will be implemented using the principles and tools of participatory monitoring and knowledge co-creation that our team has pioneered in the tropical Andes. The datasets produced by this approach, combined with existing monitoring implemented by our team and collaborators, will allow us to build an integrated water supply-demand-vulnerability assessment model for glacierized basins, and to use this to evaluate adaptation strategies at the local scale. 

This research is part of the multidisciplinary collaboration between British and Peruvian scientists (Newton Fund, Newton-Paulet).

How to cite: Rau, P., Buytaert, W., Drenkhan, F., Lavado, W., Jimenez, J., Montoya, N., Bonnesoeur, V., Valdivia, G., Cachay, W., Goyburo, A., Risco, E., Abad, J., Mackay, J., Hannah, D., Barrand, N., Siegert, M., Macera, B., Bueno, M., Baca, C., and Gianella, C.: RAHU Project: Assessing water security and climate change adaptation strategies in the glaciated Vilcanota-Urubamba river basin, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11040, https://doi.org/10.5194/egusphere-egu2020-11040, 2020.

D3405 |
Eber Risco, Waldo Lavado, and Pedro Rau

Water resources availability in the southern Andes of Peru is being affected by glacier and snow retreat. This problem is already perceived in the Vilcanota river basin, where hydro-climatological information is scarce. In this particular mountain context, any water plan represents a great challenge. To cope with these limitations, we propose to assess the space-time consistency of 10 satellite-based precipitation products (CMORPH–CRT v.1, CMORPH–BLD v.1, CHIRP v.2, CHIRPS v.2, GSMaP v.6, GSMaP correction, MSWEP v.2.1, PERSIANN, PERSIANN–CDR, TRMM 3B42) with 25 rain gauge stations in order to select the best product that represents the variability in the Vilcanota basin. For this purpose, through a direct evaluation of sensitivity analysis via the GR4J parsimonious hydrological model over the basin. GSMap v.6, TRMM 3B42 and CHIRPS were selected to represent rainfall spatial variability according with different statistical criteria, such as correlation coefficient (CC), standard deviation (SD), percentage of bias (%B) and centered mean square error (CRMSE). To facilitate the interpretation of statistical results, Taylor's diagram was used to represent the CC statistics, normalized values of SD and CRMSE.

A distributed degree-day model was chosen to analyse the sensitivity of snow cover simulations and hydrological contribution. The GR4J rainfall-runoff model was calibrated (using global optimization) and applied to simulate the daily discharge and compared with the Distributed Hydrology and Vegetation Model with Glacier Dynamics (DHSVM-GDM) over the 2001-2018 period. Furthermore, the simulated streamflow was evaluated through comparisons with observations at the hydrological stations using Nash–Sutcliffe efficiency and Kling Gupta Efficiency (KGE). The results show that the snow-runoff have increased in recent years, so new water management and planning strategies should be developed in the basin. This research is part of the multidisciplinary collaboration between British and Peruvian scientists (Newton Fund, Newton-Paulet) through RAHU project.

How to cite: Risco, E., Lavado, W., and Rau, P.: Snow-Hydrological modeling using remote sensing data in Vilcanota basin, Peru, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11515, https://doi.org/10.5194/egusphere-egu2020-11515, 2020.

D3406 |
Juan Pablo Sierra, Clementine Junquas, Jhan Carlo Epinoza, Thierry Lebel, and Hans Segura

The western Amazon and eastern flank of the Andes form what is known as the Amazon-Andes transition region. This region is characterized by the presence of the rainiest area in the Amazon basin with an average precipitation ranging from 6000 to 7000 mm per year. This rainy zone is the result of interactions between large-scale circulation and local features. However, the physical mechanisms controlling this rainfall patterns in the transition region are poorly understood. On the other hand, high precipitation values in the area, along with erosion, sediment transport and the geological mountain uplift help to explain this region as one of the most species-rich terrestrial ecosystems. Nevertheless, accelerated deforestation rates reported both in tropical Andes and central-southern Amazon threat the biodiversity hotspots and can induce alterations in land surface energy and water balances. In this context, the use of regional climate models can shed light on the possible consequences of deforestation on rainfall in the transition region.

The early results presented here are the first step in a work that seeks to gain a better understanding in the mechanisms involved in precipitation generation over the Amazon-Andes transition region, as well as the assessment of deforestation impacts on spatial and temporal rainfall variability during austral summer. The Weather Research and Forecasting (WRF) regional climate model is used with three nested domains. High resolution simulations (1km horizontal grid size) are performed over the key regions of Cuzco and Bolivian slopes. As a perspective,  deforestation scenarios following the land use change trajectory observed during the last decade will be used in future works. The results of this work can help to dimension the consequences of deforestation on key ecosystems such as Andean hotspots.

How to cite: Sierra, J. P., Junquas, C., Epinoza, J. C., Lebel, T., and Segura, H.: High Resolution WRF Regional Climate Modeling for the Andes-Amazon Transition Region: Model Validation Early Results, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11687, https://doi.org/10.5194/egusphere-egu2020-11687, 2020.

D3407 |
Fabian Drenkhan, Boris F. Ochoa-Tocachi, Pedro Rau, Walescka Cachay, Nilton Montoya, Waldo Lavado, Vivien Bonnesoeur, Javier Antiporta, Gustavo Valdivia, Francisco Román, and Wouter Buytaert

In the tropical Andes, mountain communities and coastal livelihoods downstream strongly depend on glaciers and Andean ecosystems for their water security. Year-round streamflow from glaciers, high-altitude peat bogs and hydraulic infrastructure buffer water scarcity and discharge variability in many areas. Nonetheless, climatic and non-climatic stressors are altering the hydrological regime and exacerbating human vulnerabilities. In the Vilcanota-Urubamba basin (VUB) in Southern Peru, the overall glacier area has substantially decreased by 37% between 1988 and 2016. At the same time, water demand from growing population, irrigated agriculture and hydropower is considerably increasing. This development bears threats to local water security and several challenges to long-term water management and governance in a context of data scarcity and social conflicts arising from socioenvironmental grievances, and highlights the need for interdisciplinary and interlinked water resource research and management.

In this context, the two projects Water security and climate change adaptation in Peruvian glacier-fed river basins (RAHU) and Natural Infrastructure for Water Security (NIWS) are collaborating at developing adaptation strategies to increase long-term water security in deglaciating basins in Peru. In the face of global environmental change, natural infrastructure – including forests, wetlands, and nature-based solutions – has been promoted as a buffer to attenuate the loss of hydrological ecosystem services caused by accelerated glacier shrinkage. Furthermore, natural infrastructure can provide a complement to man-made ‘grey’ infrastructure enhancing its performance, lifespan, and adaptability and provide multiple defense lines against natural disasters and other climate risks.

Here, we implemented hydrological data collection using participatory monitoring approaches and integrated ancestral and contemporary nature-based solutions. Conservation of natural grasslands can avoid streamflow variability and flashiness caused by common land-use activities such as cultivation and grazing. Flow duration curves show that median flows in cultivated catchments are approximately half those of natural catchments, whereas low flows are up to five times lower but high flows remain virtually the same. Despite being highly promoted, afforestation interventions reduce water yield significantly. High and mean daily flows in afforested catchments are approximately four times lower than in natural grasslands, whilst low flows are between seven to ten times lower. Most catchment management practices, however, are more complex, and involve a combination of interventions. An example of this are pre-Inca infiltration enhancement systems, which divert water from headwater streams onto mountain slopes to increase the yield and longevity of downslope natural springs. Tracer experiments in another study site reveal that water residence times range between 2 weeks and 8 months, with a mean of 45 days, which might be able to increase dry season flow downstream by up to 33%.

Currently, a first Water Management Plan is being implemented in the VUB and part of its headwaters have just been declared a Regional Conservation Area. This progress in local policy and headwater conservation offers new opportunities for the project consortium to provide scientific evidence to stakeholders. Our first findings have particular implications for the implementation of robust adaptation measures for future water management planning embedded into local-national policies in close collaboration with science and society.

How to cite: Drenkhan, F., Ochoa-Tocachi, B. F., Rau, P., Cachay, W., Montoya, N., Lavado, W., Bonnesoeur, V., Antiporta, J., Valdivia, G., Román, F., and Buytaert, W.: Exploring nature-based adaptation options for improved water security in the deglaciating Andes of Peru, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12510, https://doi.org/10.5194/egusphere-egu2020-12510, 2020.

D3408 |
Karen Leon, Julia Acuña, Harold Llauca, Waldo Lavado, Wilson Suarez, Jorge Ordoñez, and Oscar Felipe

The Peruvian Service of Meteorology and Hydrology (SENAMHI) provides hydro-climatological hazard information to population and decision-makers about flood forecasting and warning on the whole territory of Peru. For flash floods monitoring, a sub-daily simulation is critical to properly address the response of the watershed and prepare timely flash flood warnings. Over the last years, the city of Tumbes has been affected by the overflowing of Puyango-Tumbes river, which is born in Ecuador and flows to northwestern Peru. For this reason, the aim of this work is to develop an operational sub-daily hydrological forecast service for Puyango-Tumbes river basin.

To establish this forecasting system, we performed a continuous hydrological modelling approach on an hourly time scale for the Puyango-Tumbes basin at El Tigre stream gauge (4710 km2) in a semi-distributed way. We used the Sacramento Soil Moisture Accounting (SAC-SMA) model to simulate rainfall-runoff process and Saint-Venant equations for flow routing. Gridded hourly precipitation (~10 Km) was obtained by merging satellite-based precipitation estimates (IMERG-Early Run and GSMaP Near-Real-Time products) with rain-gauge data applying a simple bias adjustment. The model was calibrated and validated for the 2014/15 - 2018/19 period. Results show good agreement between observed and simulated hydrographs with Nash-Sutcliffe efficiency (NSE) between 0.6 and 0.8, for both products. For the highest floods, the peak is reasonably reached although there is an underestimation of 22% and 38% for calibration and validation period. The best performance was obtained for the SAC-SMA-IMERG scheme; however, sometimes rainfall at the upper Puyango-Tumbes is not well represented.

The flood forecasting operation will be performed on a daily-basis using an hourly meteorological forecast from ETA-SENAMHI climate model, at ~10 Km resolution. During this austral summer, the system will be evaluated and distributed to stakeholders.

How to cite: Leon, K., Acuña, J., Llauca, H., Lavado, W., Suarez, W., Ordoñez, J., and Felipe, O.: Implementation of a flood forecasting system in a transboundary river basin, Peru – Ecuador , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12927, https://doi.org/10.5194/egusphere-egu2020-12927, 2020.

D3409 |
Claudia Teutsch, Faizan Anwar, Jochen Seidel, András Bárdossy, Christian Huggel, Alina Motschmann, Christian D. León, and Fabian Drenkhan

High mountain regions, like the Andes, face various risks due to climate change. In the Santa River catchment in Peru which includes the glaciated Cordillera Blanca, water availability is threatened by many climatic and non-climatic impacts. The water resources in the catchment heavily rely on seasonal precipitation and during the dry season glacier melt water plays an important role. However, both, precipitation patterns and glacier extent are affected by climate change impacts. Additionally, socio-economic changes put further pressure on water resources and hence on water availability.

Within the AguaFuturo Project we established a conceptual integrated water balance model based on a semi-distributed HBV model for the data scarce Santa River catchment. The hydrological model processes are extended by feedback loops for agricultural and domestic water use. The model runs on daily time scale and includes two hydrological response units. One includes the irrigated agricultural areas which are predominately located in the valley of the catchment; the other includes non-irrigated areas and domestic water use.

To assess future water balance challenges we downscaled and disaggregated monthly CORDEX scenarios for 2020-2050 using information from the new Peruvian precipitation dataset PISCO (Peruvian Interpolated data of the SENAMHI’s Climatological and hydrological Observations) for simulations of future changes in hydro-climatology. In the model, these climate scenarios are combined with possible socio-economic scenarios which are translated into time series for domestic and agricultural water demand. The socio-economic scenarios are developed by using the Cross-Impact-Balance-Analysis (CIB), a method used for analyzing impact networks. Using CIB, the interrelations between 15 social, economic and policy descriptors were analyzed and as a result a total of 29 possible consistent scenarios were determined. For further analysis and validation of these scenarios a participatory process was included, involving local experts and stakeholders of the study region.

The climate and socio-economic scenarios are independent and can be combined randomly. The uncertainties of the climatic and socio-economic scenarios are quantified by Monte Carlo simulations.

The output of the model runs is an ensemble of possible future discharges of the Santa River, which can be further analyzed statistically to assess the range of the possible discharges. This evaluation provides an estimate of the probability of water shortages, especially with regard to conflict potential with hydropower production and the large scale irrigated agriculture areas in the adjacent coastal desert which also rely on water from the Santa River.

How to cite: Teutsch, C., Anwar, F., Seidel, J., Bárdossy, A., Huggel, C., Motschmann, A., León, C. D., and Drenkhan, F.: Integrating Climate and Socio-Economic Scenarios in a Hydrological Model for the Santa River Basin, Peru, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-16454, https://doi.org/10.5194/egusphere-egu2020-16454, 2020.

D3410 |
Lorenz Hänchen, Georg Wohlfahrt, Wolfgang Gurgiser, Fabien Maussion, Pierluigi Calanca, Alejo Cochachín Rapre, Rolando Cruz Encarnación, and Fiorella Quiñonez Collas

Small-scale farming in the Tropical Andes has been increasingly challenged by recent economic growth due to globalization of agriculture and increasing mining activities. Furthermore, in Ancash and its capital Huaraz decreasing water availability and higher water demand are a great concern for sustainable development. Recent studies have investigated the situation of small-scale farmers in hydrological sub-catchments of the Rio Santa Basin around Huaraz between the Coordillera Negra and Blanca using interdisciplinary methods. Their results show a clear disagreement between the perception of climate (or precipitation) change by local farmers and the statistical analysis of meteorological data collected at nearby weather stations. In the framework of the project AgroClim Huaraz (www.agroclim-huaraz.info), our team tries to investigate the reasons of this disparity and to assess the potential vulnerabilities and risks in local small-scale agriculture in rural areas close to Huaraz.

Recently, we installed two automatic weather stations (AWS) and a network of rain gauges (5) representing a broad range of ecosystems and altitudes along a precipitation transect (East to West). In addition, one field site has been equipped with an eddy covariance system (EC) providing continuous energy (latent and sensible heat) and carbon dioxide fluxes, while in other locations, covering the most important crop types in the region, our mobile EcoBot system has been used for periodic observations of latent and sensible heat fluxes and crop development (biomass, vegetation height) since November 2019. To date, these measurements of climate-vegetation interaction are still regularly carried out by local partners in Huaraz.

In this contribution we will (i) report for the first time the EC data, (ii) validate the EcoBot against the EC measurements and (iii) analyse the variability in crop phenology and evapotranspiration (driven by spatial differences in rainfall).

In the future, we aim to use our novel in-situ data to 1) validate remote sensing and reanalysis data, 2) run and calibrate FAOs AquaCrop model and 3) add an open-source (OS) module to AquaCrop OS integrating NDVI data (acquired by EcoBot) to drive it on larger scales with remote sensing data.

How to cite: Hänchen, L., Wohlfahrt, G., Gurgiser, W., Maussion, F., Calanca, P., Cochachín Rapre, A., Cruz Encarnación, R., and Quiñonez Collas, F.: Agro-climatic observations in Huaraz, Peru – first insights from water, energy and carbon dioxide flux measurements, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-17630, https://doi.org/10.5194/egusphere-egu2020-17630, 2020.

D3411 |
Sly Wongchuig Correa, Jhan Carlo Espinoza, Hans Segura, Thomas Condom, and Clémentine Junquas

Large evidences support the strong impacts on rainfall amount and the increasing of dry-season length on the Amazonian forest. All of these effects are usually attributed to large scale atmospheric circulation and to land cover changes as part of anthropogenic effects. In this research we assess statistical and modeling approaches to investigate the interaction between changes in forest cover and hydroclimate processes on a regional and local scale.

Henceforth, the deforestation areas and climatic indexes for the southern Amazon basin (south of 14°S) were evaluated. The deforestation map was estimated for the 1992-2018 period, based on global land cover maps at 300 m of spatial resolution produced by the European Space Agency (ESA) Climate Change Initiative (CCI) by using several remote sensing datasets. The CHIRPS rainfall dataset (P) for the 1981-2018 period was used to estimate the dry day frequency (DDF, P<1mm) and the wet day frequency (WDF, P>10mm). In addition, the mean actual seasonal evapotranspiration (AET) was GLEAM and ET-Amazon evapotranspiration datasets for the 1980-2018 and 2003-2013 periods respectively. In order to determine the local and the regional climatic effect for each pixel of the climatic index (DDF, WDF and AET), the deforestation fraction was estimated considering different spatial radii of influence (20 to 50 km).

The first results indicate a particular pattern in the southern Bolivian Amazon where two groups of areas were identified, considering the common period of analysis (1992-2018). One of them shows a significant relationship between increasing trend of DDF and decreasing trend of WDF while deforestation fraction is high, what mainly occurs during the wet season. In addition, this region is clearly placed in areas with values of deforestation fraction above ~30%, a closest value to the usually estimated Amazon Tipping Point (~40%). Below this value, the second group is also located in regions with positive trends of DDF and negative trends of WDF. This region has probably a strongest link with the large-scale climate.

Considering these preliminary results, the statistical approaches developed in this research could give some insights about the interactions between forest change and the regional hydro climatology, which might improve the understanding of this interaction based on large-scale hydrological modeling.

How to cite: Wongchuig Correa, S., Espinoza, J. C., Segura, H., Condom, T., and Junquas, C.: Investigating the interactions between Forest Cover Change and Hydroclimatic patterns in the Bolivian Amazon basin over the last 30 years, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-17876, https://doi.org/10.5194/egusphere-egu2020-17876, 2020.

D3412 |
Paula Vignoni, Rik Tjallingii, Francisco Córdoba, Birgit Plessen, Gonzalo Torres, Liliana Lupo, Norbert Nowaczyk, and Achim Brauer

Due to the meridional extension and prominent orography, the Central Andes of NW Argentina act as a topographic barrier to the moisture-bearing easterly winds. This result in contrasting climate conditions and a steep E-W rainfall gradient with high precipitation on the eastern flanks and increasing aridity westwards into the Puna plateau. Laguna Comedero is a shallow lake located in the subtropical forest of the Yungas in the eastern flank of the Argentine Eastern Cordillera (24°06'54.7" S - 65°29'7.2" W, 2,035 m a.s.l.). About 80% of the total annual precipitation (~1300 mm, Los Nogales station 1958-1989) occurs between November and March, controlled by the dynamics of the South American Monsoon System (SAMS). This region is considered sensitive to shifts in the SAMS, as well as the superposition of other large-scale phenomena (e.g. El Niño Southern Oscillation, Pacific Decadal Oscillation) but the timing and extent of precipitation changes prior to the instrumental period in this area are still largely unknown.
Here we present a combination of XRF core scanning, CN elemental analyses and stable isotopes of an 11 m-long sediment record from this lake for reconstructing the regional late Holocene climate history in this region of South America. Our results reveal a prominent shift in sedimentation, from detrital brown event-triggered silt and clay deposition and sandy intervals in the lower part of the core to an alternation of gray clastic and black organic-rich intervals in the upper 3.5 m. Below this shift in sedimentation, low TOC values (mean 0.34%) and high values of elements indicative of detrital sediments (e.g. Ti) suggest a dominance of catchment erosion processes. High TOC values of up to 20.5% in the organic-rich intervals in the uppermost 3.5 m likely reflect substantial terrestrial organic matter influx as suggestd by C/N atomic ratios around 17. δ13COM values in these intervals (-28.8 to -22.2‰) reflect the contribution of the Yungas forest (-27.9 to -27.2‰) surrounding the lake, dominated by Alnus acuminata, Polypepis australis, Podocarpus parlatorei, among other subtropical tree species. Alnus forest is related to >1000 mm/yr rainfalls. 
The pronounced alternation of organic-rich and detrital sediments in the upper 3.5 m suggest highly variable lake conditions that might be either influenced by climate and/or catchment changes and is the focus of further investigations. Preliminary dating suggests that the increase in organic matter deposition in the lake occurred at the beginning of the last millennium (ca. AD 1,000). A more detailed chronological framework is in progress including a paleomagnetic reconstruction for this area. 

How to cite: Vignoni, P., Tjallingii, R., Córdoba, F., Plessen, B., Torres, G., Lupo, L., Nowaczyk, N., and Brauer, A.: Past climate and environmental changes in the Central Andes of NW Argentina recorded in Laguna Comedero sediments, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18601, https://doi.org/10.5194/egusphere-egu2020-18601, 2020.

D3413 |
Rütger Rollenbeck, Andreas Fries, Jörg Bendix, Johanna Orellana-Alvear, Mario Guallpa, Franz Pucha, Rodolfo Rodriguez, and Rolando Celleri

The arid coastal region of Ecuador and Peru belong to the regions experiencing the strongest impact of the El-Niño-Phenomenon. In spite of neutral to cold conditions after the decaying 2015/16 El Niño, unexpected by internationl scientists and local authorities alike, in 2017 the region was hit by torrential rain falls causing floodings, erosion and landslides with many fatalities and significant damage to infrastructure.

RadarNetSur (www.radarnetsur.de), initiated in 2012 to 2015 forms the first weather radar network in that region and was capable of monitoring the development of the 2017 event up to its culmination, providing insight into rainfall distribution (resolution of 500 m) on a 5-minute time step. The network consists of 3 X-Band-scanning weather Radars with a range of 60 to 100 km, thus covering 80000 km² from 2° S to 4°S. In 2019 the network was extended far into Peru with a new system in Piura.

We present results of the analysis of the event and compare it to the conditions in the years 2014, 2015 and 2016, to point out spatial patterns and process dynamics, which led to this unusual coastal El-Niño during central Pacific La-Niña conditions. Apparently, the isolated warming of the Niño 1+2 regions off the coast was the main driver of these strong rainfalls, but the local expression of weather patterns is shaped by topographic conditions interacting with the synoptical situation (West wind bursts) and small-scale circulation systems like the sea-breeze and mountain-valley breeze. Most intense rainfall is associated with disturbances in the divergence field which are intensified by changes of the synoptical flow direction.   We assume, that either the conventional understanding of the ENSO-impact on the regional scale is insufficient, or, the ENSO-phenomenon is slowly transitioning into a more complex behavior.

How to cite: Rollenbeck, R., Fries, A., Bendix, J., Orellana-Alvear, J., Guallpa, M., Pucha, F., Rodriguez, R., and Celleri, R.: The coastal El Niño-Event of 2017 in Ecuador and Peru - a weather Radar analysis, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19903, https://doi.org/10.5194/egusphere-egu2020-19903, 2020.

D3414 |
Wouter Buytaert, Jonathan Paul, and Boris Ochoa-Tocachi and the iMHEA team

Mountain regions such as the Andes and the Himalayas are a hotspot of natural hazards. Many of them, in particular floods, landslides, and soil degradation, are related to extreme rainfall events. However, characterising rainfall is complicated by the extreme spatiotemporal gradients, and the scarcity of in situ observations. Characterising extreme rainfall events is particularly problematic because most existing rainfall records are only available at a low temporal resolution (daily or coarser). Here, we analyse records of a network of 77 tipping bucket rain gauges located in Ecuador, Peru, Bolivia and Nepal, with a data availability ranging between 1 and 10 years.

From the raw data we derive rainfall intensities at 5 and 10 minute intervals using composite cubic spline interpolation and smoothing. We then compare those intensities with instantaneous measurements from the Global Precipitation Measurement (GPM) satellite mission. Although correlations are generally low, it is possible to find significant trends that make it possible to interpolate the observed intensities in space, and to generate rainfall intensity quantile maps for the wider high Andean region.

How to cite: Buytaert, W., Paul, J., and Ochoa-Tocachi, B. and the iMHEA team: Characterising extreme rainfall over mountain regions with a network of tipping bucket rain gauges and GPM satellite data, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20371, https://doi.org/10.5194/egusphere-egu2020-20371, 2020.

D3415 |
Jose Augusto Zevallos Ruiz, Adrian Huerta, Waldo Lavado, Evelin Sabino, Fiorella vega, and Oscar Felipe

In recent years, there has been an increasing interest in estimate future conditions on biomes and aridity due to climate change. Using a new observed-based gridded dataset and remote sensing products, we evaluate the future features in terms of potential biomes (PB) and aridity index (AI) over Peru. 

Ten PBs were established for the present conditions by grouping the ecosystems maps at the national scale. The map presents biomes within areas from 1.08 to 42.44% of total coverage. In order to handle imbalanced data, we designed a calibration and validation scheme for three machine learning algorithms (Random Forest, SVM, and KNN) as follow: first, we perform a gridded search for the best parameters of each model; second, we tested the robustness of each model with a cross validations, checking their f1 score, the confusion matrix and the weighted average precision-recall; finally, we performed a cost-sensitive learning to make more suitable the learning approach for very imbalanced data. The best model is going to be used to predict future conditions of PB. For AI, we evaluate the present trend and quantified the contributions of climate variables to Ai variations. Also, the relationship between AI and vegetative greening was explored. The future change of AI is seen by its spatial variation (migration) of the dryland subtypes.

The preliminary results showed that random forest worked best for the PB imbalanced data, having a 0.84 weighted average in precision and recall metric. The model reproduces 9 of the PB with low error 4.5% and overestimates 34.52 % one of them in the Amazon. Furthermore, there is an increasing slight trend (not significant) of AI at the drainage-scale, mainly in the Pacific. We hypothesize that there is a migration of dryland subtypes from dry to wet areas in the present time. 

This research is part of the project “Apoyo a la Gestión del Cambio Climatico 2da. Fase” financed by The Swiss Agency for Development and Cooperation (SDC).

How to cite: Zevallos Ruiz, J. A., Huerta, A., Lavado, W., Sabino, E., vega, F., and Felipe, O.: Climate change impacts on biomes and aridity in Peru, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20432, https://doi.org/10.5194/egusphere-egu2020-20432, 2020.

D3416 |
Jean Carlos Ruiz, Jhan Carlo Espinoza, Clementine Junquas, Thomas Condom, Marcos Villacís, Pierre Ribstein, Nicolas Le Moine, Lenin Campozano, Andrea Vera, Teresa Muñoz, and Luis Maisincho

The spatiotemporal variability of precipitation over the complex topography of the Andean equatorial regions has recently caught the attention of researchers thanks to improvements in monitoring networks, including high temporal resolution data. Using a set of 38 rain gauges at hourly time step spanning the 2014-2015 period, this work aims to characterize the annual and diurnal cycles over the upper parts of the Guayllabamba (Andean valley) and Napo (transition zone) basins (78.65°W-77.75°W and -0.8S-0°, land area of ~10000 km2). This region drains respectively to Pacific and Amazonian rivers and is of particular interest because the region provides over 30% of the domestic water demand of the city of Quito, and presents a high glacierized volcano, the Antizana.

The annual cycle is characterized through cluster analysis of monthly rainfall showing two groups of stations that respond to bimodal and unimodal seasonal regimes and corresponds to the local boundary between the Pacific and the Amazon basins. The bimodality presents higher rainfall occurring during March-April and October-November, on the other hand, the unimodality presents its maxima in June.

A careful analysis of the evolution of the diurnal cycle during the year is done and results show that stations with bimodal annual regime peaks around 13:00-17:00 LT and in some months a second peak appears around 22:00-06:00 LT. Regarding stations with unimodal annual regime, the diurnal cycle peaks around 10:00 LT-18:00 LT and in addition shifts to 00:00-06:00 LT during June-August.

In general, the annual and diurnal cycles are useful for water management in the study zone, especially with regards to Quito’s water supply. Furthermore, the annual cycle and its relationship with altitude provides new information related to strong and weak precipitation gradients that are useful for hydro-glaciological modelling exercises. And the information on the diurnal cycle can improve some water management practices.

How to cite: Ruiz, J. C., Espinoza, J. C., Junquas, C., Condom, T., Villacís, M., Ribstein, P., Le Moine, N., Campozano, L., Vera, A., Muñoz, T., and Maisincho, L.: The annual and diurnal cycles of precipitation over an Equatorial Andean valley and its transition to the Amazon Basin: A case at the Antizana region, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20625, https://doi.org/10.5194/egusphere-egu2020-20625, 2020.

D3417 |
Manuel Figueroa, Elisa Armijos, Jhan-Carlo Espinoza, Josyane Ronchail, and Pascal Fraizy

Riparian farmers along the Peruvian Amazon River face hydrological events and poor soil conditions that put their low-land crops on high risk of production loss during the flood recession period. One of those hydrological events is a sudden reversal on the river stage known as “repiquete”, which have been poorly studied in terms of its origins. This work analyzes the hydro-meteorological mechanisms over the Andes-Amazon river basins that could produce repiquetes near Iquitos city in Peru. Repiquetes were defined and characterized for the 1996-2018 period by using river stage data from three hydrological gauging stations at Amazon, Marañón and Ucayali rivers. Furthermore, daily rainfall from high spatial resolution CHIRPS (0.05° and 0.25) and TRMM (0.25) data, as well as, daily low-level winds at 850 hPa from ERA-Interim are used to characterize rainfall and large-scale atmospheric patterns associated with repiquetes. Considering that 73 significant repiquetes (reversal > 20cm) occurred in Amazon River, 64.4% of them are preceded by repiquetes only in the Marañón River, 5.5% are preceded by repiquetes only in the Ucayali River, 20.5% are preceded by repiquetes on both rivers and the rest only registered in Amazon River without precursor defined. These results show that the main precursor of repiquetes in Amazon River is the Marañón River. Most of repiquetes are associated with abundant rainfall over the Peruvian and Ecuadorian Andes-Amazon transition region with a remarkable change of northerly winds to southerly winds regime and an easterly flow during five to three days before the beginning of repiquete in Amazon River.

How to cite: Figueroa, M., Armijos, E., Espinoza, J.-C., Ronchail, J., and Fraizy, P.: A relationship between repiquetes, rainfall and circulation low-level wind regimes over the Andean-Amazon river basin, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-22603, https://doi.org/10.5194/egusphere-egu2020-22603, 2020.