Akash Koppa

Akash Koppa
Ghent University | UGhent · Department of Environment

PhD

About

22
Publications
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241
Citations

Publications

Publications (22)
Article
Full-text available
Earth observations offer potential pathways for accurately closing the water and energy balance of watersheds, a fundamental challenge in hydrology. However, previous attempts based on purely satellite‐based estimates have focused on closing the water and energy balances separately. They are hindered by the lack of estimates of key components, such...
Article
Hydropower is a key part of the increasing shift in power production from nonrenewables to renewable energy. In regions such as Africa, hydropower reservoirs are vital for achieving several sustainable development goals, including clean water, energy, and poverty elimination. However, the operations of hydropower reservoirs are often suboptimal due...
Article
Full-text available
In recent decades, India has witnessed a rapid pace of migration from areas with intensive agriculture to populated megacities, which are faced with increasing threat from climate hazards. Greater attention is needed for vulnerable new migrants who lack necessary resources when designing adaptation and mitigation policies.
Article
Full-text available
Terrestrial evaporation (E) is a key climatic variable that is controlled by a plethora of environmental factors. The constraints that modulate the evaporation from plant leaves (or transpiration, Et) are particularly complex, yet are often assumed to interact linearly in global models due to our limited knowledge based on local studies. Here, we t...
Article
Full-text available
As CO2 concentration in the atmosphere rises, there is a need for improved physical understanding of its impact on global plant transpiration. This knowledge gap poses a major hurdle in robustly projecting changes in the global hydrologic cycle. For this reason, here we review the different processes by which atmospheric CO2 concentration affects p...
Chapter
During the past decades, consistent efforts have been undertaken to model the Earth's hydrological cycle. Multiple mathematical models have been designed to understand, predict, and manage water resources, particularly under the context of climate change. A variable that has traditionally received limited attention by the hydrological community—but...
Article
Full-text available
Biogenic volatile organic compounds (BVOCs), primarily emitted by terrestrial vegetation, are highly reactive and have large effects on the oxidizing potential of the troposphere, air quality and climate. In terms of global emissions, isoprene is the most important BVOC. Droughts bring about changes in the surface emission of biogenic hydrocarbons...
Preprint
Although evidence of hydrological responses to climate is abundant, changes in water yield (WY) in mountainous regions due to climate change and intensified cryospheric melt remain unclear, mainly because of limited observations and large uncertainties in cryosphere-hydrological modeling. In this study, we used annual runoff observations and a high...
Preprint
Full-text available
Terrestrial evaporation (E) is a key climatic variable that depends on a plethora of environmental factors. The constraints that modulate the evaporation from plant leaves (or transpiration, Et) are particularly complex, yet often assumed to interact linearly in global models due to our limited knowledge based on local experimental studies. Here, w...
Article
Water yield (WY) in the Upper Brahmaputra River (UBR) basin is important for sustaining the ecological environment in the headstream region and supplying valuable freshwater resources downstream. While recent studies indicated the presence of warming and greening trends in the region, the effects of these changes on WY are not yet understood. Here,...
Article
Full-text available
Variability and trends of the south Asian monsoon at different time scales makes the region susceptible to climate-related natural disasters such as droughts and floods. Because of its importance, different studies have examined the climatic factors responsible for the recent changes in monsoon strength. Here, using observations and climate model e...
Article
Full-text available
Food, energy, and water (FEW) nexus studies require reliable estimates of water availability, use, and demand. In this regard, spatially distributed hydrologic models are widely used to estimate not only streamflow (SF) but also different components of the water balance such as evapotranspiration (ET), soil moisture (SM), and groundwater. For such...
Article
Full-text available
In this study, in-situ soil moisture measurements are used to evaluate the accuracy of three AMSR-E soil moisture products from NASA (National Aeronautics and Space Administration), JAXA (Japanese Aerospace Exploration Agency) and VUA (Vrije University Amsterdam and NASA) over Maqu County, Source Area of the Yellow River (SAYR), China. Results show...
Article
Full-text available
In data scarce regions, seasonal hydropower planning is hindered by the unavailability of reliable long-term streamflow observations, which are required for the construction of inflow scenario trees. In this study, we develop a methodological framework to overcome the problem of streamflow data scarcity by combining precipitation forecasts from ens...
Article
Calibrating a spatially distributed hydrological model of a region with complex and highly diverse agricultural settings is a difficult task. It becomes even more challenging, if major parts of the hydrology are human controlled, e.g. through irrigation agriculture. In this study, a Soil and Water Assessment Tool (SWAT) was set up and calibrated fo...
Thesis
Full-text available
The role of satellite-based remote sensing in improving hydrologic and water resources studies in data-scarce regions is investigated. Specifically, the dissertation focuses on the development of a 1) validation framework for remotely sensed precipitation and evapotranspiration without the use of ground-based observations, 2) methodological framewo...
Article
Multivariate calibration using measurements of multiple water balance components has emerged as a potential solution for improving the performance and realism of large scale hydrologic models. In this study we develop a novel multivariate calibration framework to rigorously test whether incorporation of multiple water balance components into calibr...
Article
Despite offering spatially and temporally continuous measurements, the use of remotely sensed P and E in data-scarce catchments is hindered by the lack of ground-based measurements that enable comprehensive validation. This study proposes a novel validation framework that characterizes the combined error in the long-term average estimates of remote...
Article
We estimate net groundwater storage change in the Central Valley from Apr 2002 - Sep 2016 as the difference between inflows and outflows, precipitation, evapotranspiration, and changes in soil moisture and surface water storage. We also estimate total water storage change attributable to groundwater change using Gravity Recovery and Climate Experim...
Article
Full-text available
Abstract Dry conditions in 2013-2016 in much of the western U.S. were responsible for severe drought and led to an exceptional fire season in the Pacific Northwest in 2015. The 2016 winter was forecasted to relieve drought in the southern portion of the region as a result of increased precipitation due to a very strong El Niño signal. We summarize...
Thesis
Full-text available
In the context of global climate change, studies concerning extreme hydrometeorolological events, such as droughts and floods, are of utmost scientific and societal importance. In this study, efforts have been made to apply a coupled atmospheric-hydrologic model for the Mahanadi river basin. The study focuses on the setup and calibration of a speci...

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