Spatially distributed potential evapotranspiration modeling and climate projections

Abstract

Evapotranspiration integrates energy and mass transfer between the Earth's surface and atmosphere and is the most active mechanism linking the atmosphere, hydrosphsophere, lithosphere and biosphere. This study focuses on the fine resolution modeling and projection of spatially distributed potential evapotranspiration on the large catchment scale as response to climate change. Six potential evapotranspiration designed algorithms, systematically selected based on a structured criteria and data availability, have been applied and then validated to long-term mean monthly data for the Shannon River catchment with a 50m cell size. The best validated algorithm was therefore applied to evaluate the possible effect of future climate change on potential evapotranspiration rates. Spatially distributed potential evapotranspiration projections have been modeled based on climate change projections from multi-GCM ensembles for three future time intervals (2020, 2050 and 2080) using a range of different Representative Concentration Pathways producing four scenarios for each time interval. Finally, seasonal results have been compared to baseline results to evaluate the impact of climate change on the potential evapotranspiration and therefor on the catchment dynamical water balance. The results present evidence that the modeled climate change scenarios would have a significant impact on the future potential evapotranspiration rates. All the simulated scenarios predicted an increase in potential evapotranspiration for each modeled future time interval, which would significantly affect the dynamical catchment water balance. This study addresses the gap in the literature of using GIS-based algorithms to model fine-scale spatially distributed potential evapotranspiration on the large catchment systems based on climatological observations and simulations in different climatological zones. Providing fine-scale potential evapotranspiration data is very crucial to assess the dynamical catchment water balance to setup management scenarios for the water abstractions. This study illustrates a transferable systematic method to design GIS-based algorithms to simulate spatially distributed potential evapotranspiration on the large catchment systems.

Reference Evapotranspiration Modeling Using New Heuristic Methods

“…Estimation of ETo is a challenging task due to complex interactions between meteorological and site-specific factors [ 7 ]. Generally, there is a need to standardize a single robust method to be used at a large scale (i.e., region, large basin) for reference evapotranspiration-ETo estimation, based on limited climatological and hydrological data.…”

GEO-CWB: GIS-Based Algorithms for Parametrising the Responses of Catchment Dynamic Water Balance Regarding Climate and Land Use Changes

“…This study presents the primary results of the calculated PETS for both the baseline period and the future periods, based on climate change projections, for the Shannon River catchment in Ireland [13,32,[46][47][48][49]. The River Shannon catchment, the focus of this study, is the largest transboundary river system and catchment in the island of Ireland and one of the most important water and power resources in the Republic of Ireland, see Figure 3.…”

Impacts of climate variability and landscape pattern change on evapotranspiration in a grassland landscape mosaic

“…However, there are still some limitations. First, most studies calculate potential ET and paid less attention to effects of human activities and water constraints in arid regions (e.g., Gharbia, Smullen, Gill, Johnston, & Pilla, ; Mao et al, ). Therefore, there is an inevitable gap in understanding variations in potential ET and actual ET.…”