A Climate Data Record (CDR) for the global terrestrial water budget: 1984–2010

Abstract

Abstract. Closing the terrestrial water budget is necessary to providing consistent estimates of budget components for understanding water resources and changes over time. Given the lack of in-situ observations of budget components at anything but local scale, merging information from multiple data sources (e.g. in-situ observation, satellite remote sensing, land surface model and reanalysis) through data assimilation techniques that optimize the estimation of fluxes is a promising approach. In this study, a systematic method is developed to optimally combine multiple available data sources for precipitation (P), evapotranspiration (ET), runoff (R) and the total water storage change (TWSC) at 0.5° spatial resolution globally and to obtain water budget closure (i.e. to enforce P − ET − R − TWSC = 0) through a Constrained Kalman Filter (CKF) data assimilation technique. The resulting long-term (1984–2010), monthly, 0.5° resolution global terrestrial water cycle Climate Data Record (CDR) dataset is developed under the auspices of the National Aeronautics and Space Administration (NASA) Earth System Data Records (ESDRs) program. This dataset serves to bridge the gap between sparsely gauged regions and the regions with sufficient in-situ observations in investigating the temporal and spatial variability in the terrestrial hydrology at multiple scales. The CDR created in this study is validated against in-situ measurements like river discharge from the Global Runoff Data Centre (GRDC) and the United States Geological Survey (USGS) and ET from FLUXNET. The dataset is shown to be reliable and can serve the scientific community in understanding historical climate variability in water cycle fluxes and stores, benchmarking the current climate, and validating models.

Quantitative Analysis of Terrestrial Water Storage Changes Under the Grain for Green Program in the Yellow River Basin

“…The Jung ET is a monthly 0.5° gridded global data set from 1982 to 2011. The second monthly 0.5° ET data set (1984–2010) was from the global terrestrial water cycle Climate Data Record (CDR; Zhang, Pan, et al, ), which was obtained by combining multiple available data sources for 𝑃, 𝐸𝑇, runoff, and TWSC with enforced water budget closure. The other two ET data sets were from the Global Land Data Assimilation System (GLDAS), versions 2.0 and 2.1 (Rodell et al, ), which employed the Noah land surface model at a 0.25° spatial resolution.…”

Global Freshwater Availability Below Normal Conditions and Population Impact Under 1.5 and 2 °C Stabilization Scenarios

“…We take the summation of runoff and water storage change (includes groundwater, snowmelt, and soil moisture) of the CDR (Zhang et al, ) for the global terrestrial water budget (spatial resolution: 0.5° × 0.5°, temporal resolution: monthly, and time period: 1984–2010) to represent the baseline water availability (27 years × 12 months = 324 monthly samples). The CDR is an optimized estimation of the terrestrial water budget through merging in situ observations, satellite remote sensing, reanalysis, and land surface model outputs using data assimilation techniques.…”

“…The CDR is an optimized estimation of the terrestrial water budget through merging in situ observations, satellite remote sensing, reanalysis, and land surface model outputs using data assimilation techniques. The runoff data have been validated against in situ discharge measurements obtained from the Global Runoff Data Centre and the U.S. Geological Survey (Zhang et al, ). The water storage change data were the ensemble mean of that prepared by three centers, GeoForschungsZentrum in Potsdam; Center for Space Research at University of Texas, Austin; and Jet Propulsion Laboratory (Zhang et al, ).…”

Global Attribution of Runoff Variance Across Multiple Timescales

“…The monthly global terrestrial water budget was collected from the Terrestrial Hydrology Research Group of Princeton University (Zhang et al, ), and it includes four variables, that is, precipitation, evapotranspiration, runoff, and total water storage change. The period that this data set covers is 1984–2010 with a spatial resolution of 0.5°.…”

“…The period that this data set covers is 1984–2010 with a spatial resolution of 0.5°. Zhang et al () assimilated this data set by using multisource data such as in situ observations, remotely sensed data, GCM, and reanalysis outputs. The monthly E 0 data set covering a period from 1901 to 2015 with spatial resolution of 0.5° was extracted from CRU TS3.24.01 by the Climatic Research Unit of the University of East Anglia (https://crudata.uea.ac.uk/cru/data/hrg/).…”