Remotely sensed ensembles of the terrestrial water budget over major global river basins: An assessment of three closure techniques

Abstract Precipitation minus evapotranspiration, the net flux of water between the atmosphere and Earth’s surface, links atmospheric and terrestrial water budgets and thus represents an important boundary condition for both climate modeling and hydrological studies. However, the atmospheric–terrestrial flux is poorly constrained by direct observations because of a lack of unbiased measurements. Thus, it is usually reconstructed from atmospheric reanalyses. Via the terrestrial water budget equation, water storage estimates from the Gravity Recovery and Climate Experiment (GRACE) combined with measured river discharge can be used to assess the realism of the atmospheric–terrestrial flux in models. In this contribution, the closure of the terrestrial water budget is assessed over a number of European river basins using the recently reprocessed GRACE release 05 data, together with precipitation and evapotranspiration from the operational analyses of high-resolution, limited-area NWP models [Consortium for Small-Scale Modelling, German version (COSMO-DE) and European version (COSMO-EU)] and the new COSMO 6-km reanalysis (COSMO-REA6) for the European Coordinated Regional Climate Downscaling Experiment (CORDEX) domain. These closures are compared to those obtained with global reanalyses, land surface models, and observation-based datasets. The spatial resolution achieved with the recent GRACE data allows for better evaluation of the water budget in smaller river basins than before and for the identification of biases up to 25 mm month−1 in the different products. Variations of deseasoned and detrended atmospheric–terrestrial flux are found to agree notably well with flux derived from GRACE and discharge data with correlations up to 0.75. Finally, bias-corrected fluxes are derived from various data combinations, and from this, a 20-yr time series of catchment-integrated water storage variations is reconstructed.

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Inverse streamflow routing

Hydrology and Earth System Sciences ◽

10.5194/hess-17-4577-2013 ◽

2013 ◽

Vol 17 (11) ◽

pp. 4577-4588 ◽

Cited By ~ 18

Author(s):

M. Pan ◽

E. F. Wood

Keyword(s):

Water Budget ◽

Temporal Dynamics ◽

Water Cycle ◽

Ohio River ◽

Temporal Difference ◽

Time And Space ◽

Ohio River Basin ◽

Budget Analysis ◽

Spatially Distributed ◽

Terrestrial Water

Abstract. The process whereby the spatially distributed runoff (generated through saturation/infiltration excesses, subsurface flow, etc.) travels over the hillslope and river network and becomes streamflow is generally referred to as "routing". In short, routing is a runoff-to-streamflow process, and the streamflow in rivers is the response to runoff integrated in both time and space. Here we develop a methodology to invert the routing process, i.e., to derive the spatially distributed runoff from streamflow (e.g., measured at gauge stations) by inverting an arbitrary linear routing model using fixed interval smoothing. We refer to this streamflow-to-runoff process as "inverse routing". Inversion experiments are performed using both synthetically generated and real streamflow measurements over the Ohio River basin. Results show that inverse routing can effectively reproduce the spatial field of runoff and its temporal dynamics from sufficiently dense gauge measurements, and the inversion performance can also be strongly affected by low gauge density and poor data quality. The runoff field is the only component in the terrestrial water budget that cannot be directly measured, and all previous studies used streamflow measurements in its place. Consequently, such studies are limited to scales where the spatial and temporal difference between the two can be ignored. Inverse routing provides a more sophisticated tool than traditional methods to bridge this gap and infer fine-scale (in both time and space) details of runoff from aggregated measurements. Improved handling of this final gap in terrestrial water budget analysis may potentially help us to use space-borne altimetry-based surface water measurements for cross-validating, cross-correcting, and assimilation with other space-borne water cycle observations.

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Estimation of the Terrestrial Water Budget over Northern Eurasia through the Use of Multiple Data Sources

Journal of Climate ◽

10.1175/2011jcli3936.1 ◽

2011 ◽

Vol 24 (13) ◽

pp. 3272-3293 ◽

Cited By ~ 33

Author(s):

Tara J. Troy ◽

Justin Sheffield ◽

Eric F. Wood

Keyword(s):

Water Budget ◽

Large Scale ◽

Cold Season ◽

Northern Eurasia ◽

Past Century ◽

Multiple Sources ◽

Multiple Data ◽

Terrestrial Water ◽

The Mean

Abstract Northern Eurasia has experienced significant change in its hydrology during the past century. Much of the literature has focused on documenting and understanding the trends rather than documenting the uncertainty that exists in current estimates of the mean hydroclimatology. This study quantifies the terrestrial water budget with reanalysis, hydrologic modeling, remote sensing, and in situ observations and shows there is significant uncertainty in the estimates of precipitation, evapotranspiration, runoff, and terrestrial water storage changes. The spread among the various datasets highlights the scientific community's inability to accurately characterize the hydroclimatology of this region, which is problematic because much attention has focused on hydrologic trends using these datasets. The largest relative differences among estimates exist in the terrestrial storage change, which also is the least studied variable. Seasonally, the spread in estimates relative to the mean is largest in winter, when uncertainty in cold-season processes and measurements causes large differences in the estimates. A methodology is developed that takes advantage of multiple sources of data and observed discharge to improve estimates of precipitation, evapotranspiration, and storage changes. The method also provides a framework to evaluate the errors in datasets for variables that have no large-scale in situ measurements, such as evapotranspiration.

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Baseflow recession characterization and groundwater storage trends in northern Taiwan

Hydrology Research ◽

10.2166/nh.2017.237 ◽

2017 ◽

Vol 48 (6) ◽

pp. 1745-1756 ◽

Cited By ~ 4

Author(s):

Kun-Ta Lin ◽

Hsin-Fu Yeh

Keyword(s):

Water System ◽

Water Source ◽

River Basins ◽

Mean Value ◽

Strongly Correlated ◽

Groundwater Storage ◽

Drainage Time ◽

Terrestrial Water ◽

Channel Slope ◽

Northern Taiwan

Abstract Groundwater is a critical component of the terrestrial water budget and acts as a relatively stable water source in Taiwan. In the present study, river basins' characterization and groundwater storage trends in northern Taiwan are analyzed using the Brutsaert method. As groundwater storage sustains baseflows in a water system during dry periods, it can be assessed directly from the streamflow record. The characteristic drainage time scale value, K, varied between 34 and 84 days, with a mean value of 54 days and a standard deviation of 16 days. From correlation analysis, K is strongly correlated with the main channel slope. Based on annual values of groundwater storage over the period of record, five subbasins showed downward trends, ranging from −0.053 to −0.950 mm/year, and three subbasins exhibited upward trends, ranging from 0.111 to 0.141 mm/year. During the period of 2000–2014, the groundwater storage trends in northern Taiwan had an obvious spatial distribution. River basins with significant negative trends (mean value of −2.729 mm/year) are located in the northeast part of the study area. In contrast, the subbasins in the northwest part all showed positive trends (mean value of 0.944 mm/year) in groundwater storage.

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Data assimilation of GRACE terrestrial water storage to improve sea level rise estimates and isolate anthropogenic influences

10.5194/egusphere-egu21-6380 ◽

2021 ◽

Author(s):

Ann Scheliga ◽

Manuela Girotto

Keyword(s):

Data Assimilation ◽

Sea Level Rise ◽

Sea Level ◽

Land Surface ◽

Water Budget ◽

Water Storage ◽

Surface Model ◽

Terrestrial Water Storage ◽

Terrestrial Water ◽

Land Hydrology

Sea level rise (SLR) projections rely on the accurate and precise closure of Earth&#8217;s water budget. The Gravity Recovery and Climate Experiment (GRACE) mission has provided global-coverage observations of terrestrial water storage (TWS) anomalies that improve accounting of ice and land hydrology changes and how these changes contribute to sea level rise. The contribution of land hydrology TWS changes to sea level rise is much smaller and less certain than contributions from glacial melt and thermal expansion. Although land hydrology TWS plays a smaller role, it is still important to investigate to improve the precision of the overall global water budget. This study analyzes how data assimilation techniques improve estimates of the land hydrology contribution to sea level rise. To achieve this, three global TWS datasets were analyzed: (1) GRACE TWS observations alone, (2) TWS estimates from the model-only simulation using Catchment Land Surface Model, and (3) TWS estimates from a data assimilation product of (1) and (2). We compared the data assimilation product with the GRACE observations alone and the model-only simulation to isolate the contribution to sea level rise from anthropogenic activities. We assumed a balanced water budget between land hydrology and the ocean, thus changes in global TWS are considered equal and opposite to sea level rise contribution. &#160;Over the period of 2003-2016, we found sea level rise contributions from each dataset of +0.35 mm SLR eq/yr for GRACE, -0.34 mm SLR eq/yr for model-only, and a +0.09 mm SLR eq/yr for DA (reported as the mean linear trend). Our results indicate that the model-only simulation is not capturing important hydrologic processes. These are likely anthropogenic driven, indicating direct anthropogenic and climate-driven TWS changes play a substantial role in TWS contribution to SLR.

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Utilizing combined deviations of precipitation and GRACE-based terrestrial water storage as a metric for drought characterization: A case study over major Indian river basins

Journal of Hydrology ◽

10.1016/j.jhydrol.2019.02.053 ◽

2019 ◽

Vol 572 ◽

pp. 294-307 ◽

Cited By ~ 9

Author(s):

Debanjan Sinha ◽

Tajdarul H. Syed ◽

John T. Reager

Keyword(s):

Water Storage ◽

River Basins ◽

Terrestrial Water Storage ◽

Terrestrial Water ◽

Indian River

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A Multi-Sourced Data Retrodiction of Remotely Sensed Terrestrial Water Storage Changes for West Africa

Water ◽

10.3390/w11020401 ◽

2019 ◽

Vol 11 (2) ◽

pp. 401 ◽

Cited By ~ 1

Author(s):

Vagner Ferreira ◽

Samuel Andam-Akorful ◽

Ramia Dannouf ◽

Emmanuel Adu-Afari

Keyword(s):

West Africa ◽

Water Storage ◽

Remotely Sensed ◽

Climate Indices ◽

Terrestrial Water Storage ◽

Drought Assessment ◽

Grace Data ◽

Short Period ◽

Terrestrial Water ◽

Land Data Assimilation System

Remotely sensed terrestrial water storage changes (TWSC) from the past Gravity Recovery and Climate Experiment (GRACE) mission cover a relatively short period (≈15 years). This short span presents challenges for long-term studies (e.g., drought assessment) in data-poor regions like West Africa (WA). Thus, we developed a Nonlinear Autoregressive model with eXogenous input (NARX) neural network to backcast GRACE-derived TWSC series to 1979 over WA. We trained the network to simulate TWSC based on its relationship with rainfall, evaporation, surface temperature, net-precipitation, soil moisture, and climate indices. The reconstructed TWSC series, upon validation, indicate high skill performance with a root-mean-square error (RMSE) of 11.83 mm/month and coefficient correlation of 0.89. The validation was performed considering only 15% of the available TWSC data not used to train the network. More so, we used the total water content changes (TWCC) synthesized from Noah driven global land data assimilation system in a simulation under the same condition as the GRACE data. The results based on this simulation show the feasibility of the NARX networks in hindcasting TWCC with RMSE of 8.06 mm/month and correlation coefficient of 0.88. The NARX network proved robust to adequately reconstruct GRACE-derived TWSC estimates back to 1979.

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Evolution of low flows regulation and terrestrial water storage in the Magdalena river basin: Implications for the assessment and monitoring of potential water scarcity in river basins

10.5194/egusphere-egu2020-13396 ◽

2020 ◽

Author(s):

Juan F. Salazar ◽

Silvana Bolaños ◽

Estiven Rodríguez ◽

Teresita Betancur ◽

Juan Camilo Villegas ◽

...

Keyword(s):

River Basin ◽

Water Scarcity ◽

River Flow ◽

Water Storage ◽

River Basins ◽

Terrestrial Water Storage ◽

Social Phenomena ◽

Low Flows ◽

Terrestrial Water ◽

Magdalena River

Many natural and social phenomena depend on the regulation of river flow regimes. Regulation is defined here as the capacity of river basins to attenuate extreme flows, which includes the capacity to enhance low flows during dry periods of time. This capacity depends on how basins store and release water through time, which in turn depends on manifold processes that can be highly dynamic and sensitive to global change. Here we focus on the Magdalena river basin in northwestern South America, which is critical for water and energy security in Colombia, and has experienced water scarcity problems in the past, including the collapse of the national hydropower system due to El Ni&#241;o 1991-1992. In this basin we study the evolution of regulation and related processes from two perspectives. First, we present a widely applicable conceptual framework that is based on the scaling theory and allows assessing the evolution of regulation in river basins, and use this framework to show how the Magdalena basin&#8217;s regulation capacity has been changing in recent decades. Second, we use data from the GRACE mission to investigate variations in water storage in the basin, and identify recent decreasing trends in both terrestrial water storage and groundwater storage. Further we show that temporal and spatial patterns of water storage depletion are likely related to the occurrence of ENSO extremes and pronounced differences between the lower and higher parts of the basin, including the presence of major wetland systems in the low lands and Andean mountains in the high lands. Our results provide insights on how to assess and monitor regulation in river basins, as well as on how this regulation relates to the dynamics of low flows and water storage, and therefore to potential water scarcity problems.

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Intercomparison of terrestrial water budgets in EURO-CORDEX and TSMP evaluation runs

10.5194/egusphere-egu2020-5745 ◽

2020 ◽

Author(s):

Mohamed Eltahan ◽

Klaus Goergen ◽

Carina Furusho-Percot ◽

Stefan Kollet

Keyword(s):

Land Surface ◽

Water Budget ◽

Climate Models ◽

Water Cycle ◽

Weather Prediction ◽

Regional Climate ◽

Shallow Groundwater ◽

Surface Model ◽

Frequency Distributions ◽

Terrestrial Water

Water is one of Earth&#8217;s most important geo-ecosystem components. Here we present an evaluation of water cycle components using 12 EURO-CORDEX Regional Climate Models (RCMs) and the Terrestrial Systems Modeling Platform (TSMP) from ERA-Interim driven evaluation runs. Unlike the other RCMs, TSMP provides an integrated representation of the terrestrial water cycle by coupling the numerical weather prediction model COSMO, the land surface model CLM and the surface-subsurface hydrological model ParFlow, which simulates shallow groundwater states and fluxes. The study analyses precipitation (P), evapotranspiration (E), runoff (R), and terrestrial water storage (TWS=P-E-R) at a 0.11degree spatial resolution (about 12km) on EUR-11 CORDEX grid from 1996 to 2008. As reference datasets, we use ERA5 reanalysis to represent the complete terrestrial water budget, as well as the E-OBS, GLEAM and E-Run datasets for precipitation, evapotranspiration and runoff, respectively. The terrestrial water budget is investigated for twenty catchments over Europe (Guadalquivir, Guadiana, Tagus, Douro, Ebro, Garonne, Rhone, Po, Seine, Rhine, Loire, Maas, Weser, Elbe, Oder, Vistuala, Danube, Dniester, Dnieper, and Neman). Annual cycles, seasonal variations, empirical frequency distributions, spatial distributions for the water cycle components and budgets over the catchments are assessed. The analysis demonstrates the capability of the RCMs and TSMP to reproduce the overall characteristics of the water cycle over the EURO-CORDEX domain, which is a prerequisite if, e.g., climate change projections with the CORDEX RCMs or TSMP are to be used for vulnerability, impacts, and adaptation studies.

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