Trends in evapotranspiration and its drivers in Great Britain: 1961 to 2015

Abstract

In a warming climate, the water budget of the land is subject to varying forces such as increasing evaporative demand, mainly through the increased temperature, and changes to the precipitation, which might go up or down. Using a verified, physically based model with 55 years of observation-based meteorological forcing, an analysis of the water budget demonstrates that Great Britain is getting warmer and wetter. Increases in precipitation (2.96.0 ± 2.03 mm yr–1 yr–1) and air temperature (0.20 ± 0.13 K decade–1) are driving increases in runoff (2.18 ± 1.84 mm yr–1 yr–1) and evapotranspiration (0.87 ± 0.55 mm yr–1 yr–1), with no significant trend in the soil moisture. The change in evapotranspiration is roughly constant across the regions, whereas runoff varies greatly between regions: the biggest change is seen in Scotland (4.56 ± 2.82 mm yr–1 yr–1), where precipitation increases were also the greatest (5.4 ± 3.0 mm yr–1 yr–1), and the smallest trend (0.33 ± 1.50 mm yr–1 yr–1, not statistically significant) is seen in the English Lowlands (East Anglia and Midlands), where the increase in rainfall is not statistically significant (1.07 ± 1.76 mm yr–1 yr–1). Relative to its contribution to the evapotranspiration budget, the increase in interception is higher than the other components. This is due to the fact that it correlates strongly with precipitation, which is seeing a greater increase than the potential evapotranspiration. This leads to a higher increase in actual evapotranspiration than the potential evapotranspiration, and a negligible increase in soil moisture or groundwater store.

Long-Term Homogeneity and Trends of Hydroclimatic Variables in Upper Awash River Basin, Ethiopia

“…Trend analysis is an effective method to detect changes in climatic and hydrological variables [14,16,20,26,55,[59][60][61]. e Mann-Kendall test has been widely used to detect trends in reference evapotranspiration, streamflow, temperature, and precipitation time series in different regions around the world [14,15,23,24,47,[62][63][64][65]. In this study, a modified Mann-Kendall trend test was used to detect the change in streamflow, rainfall, and average temperature.…”

CAMELS-GB: hydrometeorological time series and landscape attributes for 671 catchments in Great Britain

“…With the emergence of new digital technologies and increased monitoring of the earth system via satellites and sensors, we now have greater access to data than ever before. This prolifera-tion of data has been reflected in recent projects where there has been a focus on sharing data and collaborative research (SWITCH-ON; Ceola et al, 2015), collecting new datasets through the creation of terrestrial environmental observatories (TERENO; Zacharias et al, 2011) or the Critical Zone Observatories (CZOs; Brantley et al, 2017), and cloud-based resources for modelling and visualising large datasets such as the Environmental Virtual Observatory (EVO; Emmett et al, 2014) and the CUAHSI HydroDesktop (Ames et al, 2012).…”

A regional coupled approach to water cycle prediction during winter 2013/14 in the United Kingdom

“…In common with the evolution of other land surface models (Blyth et al, 2021;Clark et al, 2015), JULES is increasingly being applied and assessed with a view to have a more complete representation of terrestrial hydrology in addition to continuing focus on the representation of land-atmosphere coupling as has been more traditional in their use as an interacting lower boundary for weather and climate prediction. It has been previously demonstrated that JULES can provide accurate daily river flow simulations over selected catchments in Great Britain when driven by observation-based meteorological forcing (Martinez-de la Torre et al, 2019), while G omez et al (2020 demonstrated good river flow predictions when driven by an operational JULES-based regional land surface analysis. There are however known deficiencies in the hydrological performance of JULES over the UK, including excessive evaporation rates (Blyth et al, 2019), insufficient infiltration (Largeron et al, 2018) and numerous inherent parameterisation and parameter uncertainties (Martinezde la .…”