Analysis of long-term terrestrial water storage variations in the Yangtze River basin

Y Huang,Z Su,Y Zhou,R Van Der Velde,M S Salama,A Y Hoekstra,M S Krol

doi:10.5194/hess-17-1985-2013

Abstract

Abstract. In this study, we analyze 32 yr of terrestrial water storage (TWS) data obtained from the Interim Reanalysis Data (ERA-Interim) and Noah model from the Global Land Data Assimilation System (GLDAS-Noah) for the period 1979 to 2010. The accuracy of these datasets is validated using 26 yr (1979–2004) of runoff data from the Yichang gauging station and comparing them with 32 yr of independent precipitation data obtained from the Global Precipitation Climatology Centre Full Data Reanalysis Version 6 (GPCC) and NOAA's PRECipitation REConstruction over Land (PREC/L). Spatial and temporal analysis of the TWS data shows that TWS in the Yangtze River basin has decreased significantly since the year 1998. The driest period in the basin occurred between 2005 and 2010, and particularly in the middle and lower Yangtze reaches. The TWS figures changed abruptly to persistently high negative anomalies in the middle and lower Yangtze reaches in 2004. The year 2006 is identified as major inflection point, at which the system starts exhibiting a persistent decrease in TWS. Comparing these TWS trends with independent precipitation datasets shows that the recent decrease in TWS can be attributed mainly to a decrease in the amount of precipitation. Our findings are based on observations and modeling datasets and confirm previous results based on gauging station datasets.

Highlights

Terrestrial water storage (TWS) is determined by all physical phases of water stored above and below the surface of the Earth, including soil moisture, snow and ice, canopy water storage, groundwater, etc
We neglect canopy water storage (CWS), this is included in the Global Land Data Assimilation System (GLDAS)-Noah simulation
To explore the quality of these datasets further and as precipitation arguably forms the most critical input into an accurate TWS, precipitation estimates of ERA-Interim and GLDAS-Noah are compared with products from the Global Precipitation Climatology Centre (GPCC) and PRECipitation REConstruction over Land (PREC/L), which are derived more directly from observations

Summary

Introduction

Terrestrial water storage (TWS) is determined by all physical phases of water stored above and below the surface of the Earth, including soil moisture, snow and ice, canopy water storage, groundwater, etc. As a key component of terrestrial and global hydrological cycles, TWS strongly influences water, energy, and biogeochemical fluxes, thereby playing a major role in the Earth’s climate system (Famiglietti, 2004). Soil moisture plays a key role in both the water and energy cycles through its impact on the energy partitioning at the surface, and soil moisture has links with the biogeochemical cycle via plant transpiration and photosynthesis (Seneviratne et al, 2010). The spatial and temporal variability in TWS due to climate change and human-induced impacts both form important components in the water and energy cycles, and should be taken into account in river basin management

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