Title: Estimation of variations in river basin water storage from in-situ and satellite observation of the time dependent gravity field

Primary Researcher: Shaakeel Hasan
Email address: s.hasan@uu.nl
Submitted on: July 18, 2003

Start date: 01 March 2003
End date: 28 February 2007

Introduction:

The main problem in any hydrological study is that almost all of the stocks and fluxes in a hydrologic cycle are difficult to measure, and if measured or estimated, the accuracy is questionable. So it continues to occupy the hydrologists finding a better (!) way of quantifying different hydrological processes. Recent developments can be classified into measurement techniques and a way to model the spatial and temporal variability of hydrological processes. Example of the first can be radar rainfall estimation, satellite remote sensing for near surface soil moisture, satellite altimetry for surface water, etc. while the example for the later can be different assumptions for various hydrological modelling, mainly distributed over space.

Gravity, the universal force of attraction that affects all matter, is the weakest of the four basic physical forces (the others being the electromagnetic force, and the strong and weak nuclear binding forces), but this is the one that influences nearly all physical, chemical, and biological processes. In fact in Geodynamics or Geophysics, gravity methods are traditionally used, looking at its spatial variation. The advancement of the gravimeters reveals the timely variation of the gravity that has to do with not only the fact of earth’s rotation or earth and ocean tide, but also the fact of the timely variation of mass and its distribution. The main part of this mass variation is necessarily water of which the quantity changes in or on the ground as well as in the atmosphere. Thus the advancement of gravity field measurement techniques, both in-situ and satellite based, promises a significant development in hydrological studies, in terms of quantifying different hydrological stocks and fluxes.

The idea of this research project is to learn about changes in the total vertically integrated water storage by combining gravity signal with complementary environmental and soil-physical observation, and to quantify hydrological signals.

Aim:

Research:

The objective of this study is to investigate the possibility to detect variations in river basin water storage from measurements of the time dependent gravity field, and to assess the accuracy of these estimations based on in-situ and satellite observations of the gravity field. The hypothesis is that time dependent gravity measurements, both in-situ and satellite based, contain information about water storage in surface and subsurface reservoirs (aquifers, unsaturated zone).

Funding via NWO

Yes