nasa-gesdisc/es-publications-researchareas huggingface dataset:
Recent global decline in endorheic basin water storages (2018)

Endorheic (hydrologically landlocked) basins spatially concur with arid/semi-arid climates. Given limited precipitation but high potential evaporation, their water storage is vulnerable to subtle flux perturbations, which are exacerbated by global warming and human activities. Increasing regional evidence suggests a probably recent net decline in endorheic water storage, but this remains unquantified at a global scale. By integrating satellite observations and hydrological modelling, we reveal that during 20022016 the global endorheic system experienced a widespread water loss of about 106.3 Gt yr1, attributed to comparable losses in surface water, soil moisture and groundwater. This decadal decline, disparate from water storage fluctuations in exorheic basins, appears less sensitive to El NinoSouthern Oscillation-driven climate variability, which implies a possible response to longer-term climate conditions and human water management. In the mass-conserved hydrosphere, such an endorheic water loss not only exacerbates local water stress, but also imposes excess water on exorheic basins, leading to a potential sea level rise that matches the contribution of nearly half of the land glacier retreat (excluding Greenland and Antarctica). Given these dual ramifications, we suggest the necessity for long-term monitoring of water storage variation in the global endorheic system and the inclusion of its net contribution to future sea level budgeting.

Research areas: Land Surface/Agriculture Indicators, Atmospheric/Ocean Indicators
Vulnerability of the Caspian Sea shoreline to changes in hydrology and climate (2020)

During the past three decades, sea water level (SWL) in the Caspian Sea has declined by about 2 m and sea area has decreased by about 15 000 km<SUP>2</SUP>. This has affected coastal communities, the environment and economically important gulfs of the sea (e.g. Dead Kultuk). To assess the effects of coastline change and evaluate zones vulnerable to desiccation, we simulated SWL using total inflow from feeder rivers and precipitation and evaporation over the sea. We determined potential vulnerable areas of the sea over the past 80 years by comparing the minimum and maximum annual water body maps (for 1977 and 1995). We then determined the linear regression between SWL rise and covered potential vulnerable area (CVA), using annual Normalised Difference Water Index (NDWI) maps and SWL data from 1977 to 2018. Combining SWL-CVA regression and SWL simulation model enabled us to determine desiccated areas in different regions of the Caspian Sea due to changes in precipitation, evaporation and total inflow. The results showed that 25 000 km<SUP>2</SUP> of the sea is potentially vulnerable to SWL fluctuations in terms of desiccation, with 70% of this vulnerable area located in Kazakhstan. Potential vulnerable area per kilometre coastline was found to be 6 km<SUP>2</SUP> in Kazakhstan, 4 km<SUP>2</SUP> in Russia and whole of Caspian Sea, 1.5 km<SUP>2</SUP> in Iran, 1 km<SUP>2</SUP> in Azerbaijan and 0.5 km<SUP>2</SUP> in Turkmenistan. The results also indicated that SWL in the Caspian Sea is sensitive to evaporation and that e.g. a 37.5 mm decrease in mean annual net precipitation would lead to a 1875 km<SUP>2</SUP> decrease in the sea area, while a 1 km<SUP>3</SUP> decrease in mean annual inflow would lead to a 1400 km<SUP>2</SUP> decrease in the sea area. Thus the developed framework enabled the spatial consequences of changes in water balance parameters on sea area to be quantified. It can be used to assess future changes in SWL and sea area due to anthropogenic activities and climate change.

Research areas: Atmospheric/Ocean Indicators, Habitat Conversion/Fragmentation
Restoring water quality in the polluted Turag-Tongi-Balu river system, Dhaka: Modelling nutrient and total coliform intervention strategies (2018)

River water quality in rapidly urbanising Asian cities threatens to damage the resource base on which human health, economic growth and poverty reduction all depend. Dhaka reflects the challenges and opportunities for balancing these dynamic and complex trade-offs which goals can be achieved through effective policy interventions. There is a serious problem of water pollution in central Dhaka, in the Turag-Tongi-Balu River system in Bangladesh with the river system being one of the most polluted in the world at the moment. A baseline survey of water chemistry and total coliforms has been undertaken and shows dissolved oxygen close to zero in the dry season, high organic loading together with extreme levels of Ammonium-N and total coliform in the water. Models have been applied to assess hydrochemical processes in the river and evaluate alternative strategies for policy and the management of the pollution issues. In particular models of flow, Nitrate-N, Ammonium-N and indicator bacteria (total coliforms) are applied to simulate water quality in the river system. Various scenarios are explored to clean up the river system, including flow augmentation and improved effluent treatment. The model results indicate that improved effluent treatment is likely to have a more significant impact on reducing Ammonium-N and total coliforms than flow augmentation, but a combined strategy would greatly reduce the pollution problems in the Turag-Tongi-Balu River System.

Research areas: Water Quality
Assessing hydrologic and water quality effects of land use conversion to (2021)

Carinata (Brassica carinata) is an industrial oilseed feedstock for renewable fuels grown as a winter crop in the southeast US, which may provide a new rotation alternative and benefits for water quality. However, the effects of carinata on water quantity and quality at the watershed and local scales are unknown. In this study, we use the Soil and Water Assessment Tool (SWAT) to assess the potential influence of carinata on water balance components, nutrients and sediment loads under plausible future scenarios of land use change in the upper Suwannee River Basin in the Atlantic Coastal Plain Physiographic Region near Tifton in South‑Central Georgia. Three future scenarios are considered, including planting stand‑alone carinata in winter fallow land every third year, planting stand‑alone winter wheat in winter fallow land every third year, and carinata and winter wheat in rotation, one year of winter carinata followed by two years of winter wheat during simulation periods. The results show that under all three future scenarios, surface runoff, sediment, phosphorus, and nitrogen loadings decrease at both watershed and local scales, with higher average monthly reductions in the stand‑alone carinata scenario versus the stand‑alone winter wheat scenario. When carinata and winter wheat were planted over 36% of the total watershed area, reduction in total sediment, mineral phosphorus, and nitrate loads was ranging from 11.5% to 50.0%. However, when only 12% of the total watershed area was converted to carinata, the simulated reductions ranged from 3.8% to 14.0%. This suggests that the extent of carinata planting is crucial in assessing its hydrologic and water quality benefits. Overall, these results indicate that planting the biofuel carinata as a winter crop can reduce sediment and nutrient loading and provide water quality benefits to downstream waterbodies.

Research areas: Water Quality, Habitat Conversion/Fragmentation, Agriculture
Hydropower Development in the Brazilian Amazon (2016)

Brazil plans to meet the majority of its growing electricity demand with new hydropower plants located in the Amazon basin. The governments energy policy forecasts the construction of 55 GW of installed capacity by 2028, with total investments in the range of 100 and 200 billion reais (30 to 60 billion dollars), and the creation 9,000 km2 of artificial reservoirs. However, the construction and operation of large hydropower plants may affect the environment, the local economy, and the population surrounding those projects. Considering the magnitude of the investments and the potential impacts for the Amazon basin, it is crucial to apply policy analysis techniques to support informed decisions about whether the construction of large hydropower plants in the Amazon is the best alternative to supply the additional electricity that Brazil needs, taking into account economic, social, and environmental costs and benefits. Here, I apply three different quantitative policy analysis techniques to assess three major questions related to the construction of hydropower plants in the Amazon region. First, I study the greenhouse gas emissions from hydropower reservoirs in the Amazon. Second, I explore the local socio-economic impacts of building hydropower plants. Finally, I investigate alternative electricity sources that could replace Amazon hydropower reservoirs by modeling the Brazilian electricity network under five capacity expansion scenarios.

Research areas: Energy Production/Use, Greenhouse Gases
Conversion of grazed pastures to energy cane as a biofuel feedstock alters the emission of GHGs from soils in Southeastern United States (2018)

The cultivation of energy cane throughout the Southeastern United States may displace grazed pastures on organic soil (Histosols) to meet growing demands for biofuels. We combined results from a field experiment with a biogeochemical model to improve our understanding of how the conversion of pasture to energy cane during early crop establishment affected soil GHG (CO2, CH4, and N2O) exchange with the atmosphere. GHG fluxes were measured under both land uses during wet, hot and cool, dry times of year, and following a fertilization event. We also simulated the impact of changes in precipitation on GHG exchange. Higher fertilization of cane contributed to greater emission of N2O than pasture during warmer and wetter times of the year. The model predicted that energy cane emitted more nitrogen than pasture during simulated wetter than drier years. The modeled emission factor for N2O was 20 to 30-fold higher than the default value from IPCC (1%), suggesting that the default IPCC value could dramatically underestimate the consequences of this land conversion on the climate system. Predicted soil CH4 and CO2 fluxes were higher in pasture than energy cane, and this difference was not affected by increasing precipitation. Model simulations predicted that soils under first year cane emit more GHGs than pasture, particularly during wet years, but this difference disappeared two years after energy cane establishment. Our results suggest that management practices may be important in determining soil GHG emissions from energy cane on organic soils particularly during the first year of cane establishment.

Research areas: Energy Production/Use, Greenhouse Gases, Agriculture
Solar and wind energy potential assessment at provincial level in Nepal: Geospatial and economic analysis (2022)

Renewable energies, such as solar and wind energy, play a critical role in achieving rapid decarbonization to limit global warming by replacing fossil energy. However, lack of knowledge on renewable energy potentials in developing countries is a barrier in making adequate policies to promote these energies. Thus, we have carried out a spatial and economic analysis of solar and wind energy potential at the provincial level for the first time in Nepal. Our analysis is built upon the spatial energy modeling based on technical, geographical, and economic suitability criteria, utilizing open-source geographical information system platforms. A significant amount of renewable energy could be harnessed in Nepal, i.e., up to about 47,628 MW and 1,686 MW from solar and wind energy, respectively. Similarly, Nepal has a co-location potential of about 890 and 267 MW of solar and wind energy. Karnali and Gandaki provinces have the highest solar and wind energy potential due to a large share of suitable locations with good resource quality. We estimate the 10th percentile of Levelized cost of electricity generation of 91 USD/MWh for solar and 46 USD/MWh for wind. Our findings are helpful for the formulation of resource-specific policies of Nepal at a sub-national level.

Research areas: Energy Production/Use
Cleaner air would enhance Indias annual solar energy production by 628 TWh (2022)

Abstract
            India has set a target of 100 GW solar installation capacity by the year 2022. However, the loss of solar energy due to environmental factors like air pollution is not properly considered in renewable energy resource assessments. Here we show that India lost 29% of its utilizable global horizontal irradiance potential due to air pollution between 2001 and 2018. The average loss in output incurred by solar power systems with horizontal, fixed-tilt, single-axis, and dual-axis trackers due to air pollution is estimated to be 12%, 26%, 33%, and 41%, respectively, equivalent to a loss of 245835 million USD annually. The successful implementation of the National Clean Air Program and the complete mitigation of household emissions through the supply of cleaner fuel for domestic use and rural electrification would allow India to generate a surplus of 616 TWh of electricity per year from the existing installed solar power capacity in 2018. This translates to an economic benefit of 325845 million USD annually, which is equivalent to the implementation costs of these social programs. Mitigating air pollution would therefore accelerate Indias progress towards achieving its solar energy target at a lesser installation capacity, avoiding additional expenditure for the expansion of the solar energy infrastructure.

Research areas: Energy Production/Use, Sun-Earth Interactions, Air Quality
Optimum daily operation of a wind-hydro hybrid system (2022)

Due to the negative effects of fossil fuels on the environment and health, energy supply is shifting towards renewables. The integration of renewable energy systems is challenging due to the intermittent nature of renewables, however this can be mitigated through storage. Uncertainty in electricity prices in spot markets further complicates the operation of these systems. Pumped storage hydropower is currently the most viable form of large-scale energy storage, and operation of renewable energy systems together with pumped storage hydropower plants is highly efficient. In this study, optimum daily operation strategies are developed for a wind-hydro hybrid system. A long short-term memory network to forecast electricity prices in the day-ahead spot electricity market is coupled with an optimization model to maximize daily revenue. Various scenarios are considered to investigate the benefits of future electricity price estimations. For the wind-hydro hybrid system with 25 MW wind turbine, the net revenue for one-year test period increased 3.5% when forecasted electricity prices with the proposed long short-term memory network is used instead of electricity prices of the previous day. It is observed that increasing the installed capacity of wind turbines compensates for the loss resulting from the poor forecasting of electricity prices; however, the operation schedules of the pump and the hydro turbine do not change when the optimization model uses a simulation duration of one day with hourly time steps.

Research areas: Energy Production/Use
Sources of black carbon in the atmosphere and in snow in the Arctic (2019)

We systematically identify sources of black carbon (BC) in the Arctic, including BC in the troposphere, at surface and in snow, using tagged tracer technique implemented in a 3D global chemical transport model GEOS-Chem. We validate modeled BC sources (fossil fuel combustion versus biomass burning) against carbon isotope measurements at Barrow (Alaska), Zeppelin (Norway), Abisko (Sweden), Alert (Canada) and Tiksi (Russia) in the Arctic. The model reproduces the observed annual mean fraction of biomass burning (fbb, %) at the five sites within 20% and the observed and modeled monthly fbb values agree within a factor of two. Model results suggest that fossil fuel combustion is the major source of BC in the troposphere (5094%, vary with sub-regions), at surface (5568%) and in snow (5869%) in the Arctic as annual mean, but biomass burning dominates at certain altitudes (600800 hPa) and during periods of time between April to September. The model shows that BC in the troposphere, in deposition and in snow in different Arctic sub-regions have distinctively different sources and source regions. We find that long-range transport of Asian emissions has a stronger influence on BC in the atmosphere than on BC deposition. In contrast, contributions from Russian and European emissions are larger for BC deposition than for BC in the atmosphere. Specifically, Asian fossil fuel combustion emissions dominate BC loading in all Arctic sub-regions in both winter (Oct.Mar., 3554%) and summer (Apr.Sep., 3456%). For BC deposition, Siberian fossil fuel emissions are the largest contributors in Russia both in winter (62%) and summer (44%), and European fossil fuel emissions dominate in Ny-Alesund (44% in winter) and Troms (71% in winter and 46% in summer). For BC deposition in the North American sector, Asian fossil fuel emissions are the largest contributors in winter (2538%) and North American biomass burning emissions (3872%) dominate in summer.

Research areas: Energy Production/Use, Air Quality
Different Drivers Behind Corporate Environmental Policies: The Case of the Swedish and Chilean Copper Industry (2021)

This chapter represents a comparative study of the emergence of environmental policies in the Chilean and Swedish copper industry. The chapter identifies a number of key factors which helps to explain dissimilar characteristics of actions to protect the environment in both countries as well as the timing for these actions. One key difference identifiedbesides obvious factors such as income levels, political systems and dependency of foreign direct investmentsconcerns the very drivers behind the greening of the industry. While governmental regulation developing from the 1960s represented the primary driver behind the green transformation of Swedish copper industry, it took until the 1990s before the Chilean copper companies started to adopt their first environmental policies ahead of regulation, and called for the Chilean government to act. We suggest that this happened as globalisation took hold from the early 1990s, and foreign companies operating in Chile demanded environmental standards that harmonised with those in the Western world, at the same time as the Chilean industry needed to enhance an environmental reputation in the global market. Thus, while the Swedish industry was much driven by national regulation to invest in cleaner technologies, it was the pressure from globalisation that drove the Chilean industry to clean up their acts.

Research areas: Environmental Impacts
Forest loss is significantly higher near clustered small dams than single large dams per megawatt of hydroelectricity installed in the Brazilian Amazon (2022)

Abstract
            
              Hydropower in the Brazilian Amazon is a prevalent form of development, but dams have widespread and long-term environmental impacts that include deforestation in the areas surrounding the dams. Small hydropower plants (SHPs) are often perceived as having reduced environmental impacts compared to the large ones. In Brazil, SHPs are licensed by state governments, which have less strict requirements than the federal environmental agency. Brazils definition of small dams has grown with successive increases in the maximum installed capacity from 10 to 30 to 50 megawatts (MW). This expanding loophole has increased the attractiveness of investing in multiple small dams rather than a single large dam, with resulting proliferation of SHPs. Forest dynamics surrounding the clustered SHPs when compared to single large dams are not well documented. In this study, we capitalized on a dense time series of satellite images to quantify and compare forest loss in the regions (over 110 000 km
              2
              in area) surrounding 15 SHPs and 7 large dams at multiple watershed and buffer scales in the Brazilian Amazon for nearly two decades (20002018). The landscapes containing SHP clusters had lower cumulative forest loss as compared to those with large dams. However, when deforestation and hydroelectric generating capacity were jointly considered (i.e. forest loss per megawatt installed), we discovered an opposite trend. The regions surrounding the SHP clusters exhibited significant impacts ranging from 1.9 to 2.5 times that of the regions surrounding large dams across 5 km to sub-basin scales. Due to the considerable consequences of SHPs on deforestation, we argue that the rapid expansion of small hydropower should be approached with caution and requires more stringent environmental assessments.

Research areas: Energy Production/Use, Habitat Conversion/Fragmentation
Techno-economic analysis and wind resource assessment for Odisha, India using reanalysis and 80 m mast measurements: a preliminary assessment for policy-makers (2022)

In this work, the relationship between various wind turbine parameters is investigated utilising wind resource data measured at an 80 m measurement mast. Turbine Performance Index (TPI), wind turbulence and direction are investigated to ensure favourable conditions for turbine installation. Economic analysis is performed with reference to the latest Clean Development Mechanism (CDM) registered projects. The life cycle cost and cost of generation for a prospective wind farm are 2691 million INR and 2.97 INR/kWh, respectively. Finally, using five years of NASA MERRA-2 reanalysis data for twelve locations, Weibull parameters and wind power density (WPD) at 50, 80, 120 and 150 m heights are obtained. The installed capacity is 264 MW for selected locations. Energy capture and emission reduction estimates are also computed for all the locations where the highest values of 122 million kWh and 100057 tonnes of CO2 are obtained for Paradeep.

Research areas: Energy Production/Use
Spatial analysis of indicators affecting the exploitation of shallow geothermal energy at European scale (2021)

Shallow Geothermal Energy (SGE) exploited by vertical close loop Ground Source Heat Pumps (GSHP) is a proven, reliable, and widespread renewable heating and cooling technology. However, in many regions there is still a lack of awareness among policy makers and end users, constituting a major constraint to wider deployment of SGE. In order to contribute to its market consolidation, this work focuses on bringing to light relevant spatial information affecting the suitability of SGE exploitation. This information is the result of the systematization of geological, climatic, and environmental open and available data translated into performance indicators. A set of thematic maps was created using Geographic Information Systems (GIS) comprising the European Member States and other European countries. The relative area and the amount of population affected per indicator was spatially analyzed to determine the most common values found and the affected population. The relationship between area percentage and population affected percentage per indicator was also analyzed and allowed to identify the most common indicators values in areas where high energy demands are expected. Additionally, an example of how this data can be used into a Multi-Criteria Decision-Making (MCDM) framework is shown.

Research areas: Energy Production/Use