Shilpa M. Asokan

Inland hydro-climatic interaction: Effects of human water use on regional climate

This study has quantified the regional evaporation and evapotranspiration changes, and the associated latent heat flux and surface temperature changes in the Central Asian region of the Aral Sea dr ...

Vapor flux by evapotranspiration : effects of changes in climate, land-use and water-use

Enhanced evapotranspiration (ET) over irrigated land and associated latent heat flux change can modify the climate. Model studies of such climate change effects of irrigation are commonly based on ...

Implications of freshwater flux data from the CMIP5 multimodel output across a set of Northern Hemisphere drainage basins

The multimodel ensemble of the Coupled Model Intercomparison Project, Phase 5 (CMIP5) synthesizes the latest research in global climate modeling. The freshwater system on land, particularly runoff, has so far been of relatively low priority in global climate models, despite the societal and ecosystem importance of freshwater changes, and the science and policy needs for such model output on drainage basin scales. Here we investigate the implications of CMIP5 multimodel ensemble output data for the freshwater system across a set of drainage basins in the Northern Hemisphere. Results of individual models vary widely, with even ensemble mean results differing greatly from observations and implying unrealistic long-term systematic changes in water storage and level within entire basins. The CMIP5 projections of basin-scale freshwater fluxes differ considerably more from observations and among models for the warm temperate study basins than for the Arctic and cold temperate study basins. In general, the results call for concerted research efforts and model developments for improving the understanding and modeling of the freshwater system and its change drivers. Specifically, more attention to basin-scale water flux analyses should be a priority for climate model development, and an important focus for relevant model-based advice for adaptation to climate change.

Irrigation Effects on Hydro-Climatic Change: Basin-Wise Water Balance-Constrained Quantification and Cross-Regional Comparison

Hydro-climatic changes driven by human land and water use, including water use for irrigation, may be difficult to distinguish from the effects of global, natural and anthropogenic climate change. This paper quantifies and compares the hydro-climatic change effects of irrigation using a data-driven, basin-wise quantification approach in two different irrigated world regions: the Aral Sea drainage basin in Central Asia and the Indian Mahanadi River Basin draining into the Bay of Bengal. Results show that irrigation-driven changes in evapotranspiration and latent heat fluxes and associated temperature changes at the land surface may be greater in regions with small relative irrigation impacts on water availability in the landscape (here represented by the Mahanadi River Basin) than in regions with severe such impacts (here represented by the Aral region). Different perspectives on the continental part of Earth’s hydrological cycle may thus imply different importance assessments of various drivers and impacts of hydro-climatic change. Regardless of perspective, however, actual basin-wise water balance constraints should be accounted to realistically understand and accurately quantify continental water change.

Water Scarcity In The Aral Sea Drainage Basin: Contributions Of Agricultural Irrigation Anda Changing Climate

Changed ambient conditions in the Aral Sea Drainage Basin (ASDB) in Central Asia have led to drastically decreased river discharges into the Aral Sea during the twentieth century. This decrease has ...