Characterization and Space-Time Downscaling of the Inundation Extent over the Inner Niger Delta Using GIEMS and MODIS Data

Aires, Filipe and Papa, Fabrice and Prigent, Catherine and Cretaux, Jean-Francois and Berge-Nguyen, Muriel (2014) Characterization and Space-Time Downscaling of the Inundation Extent over the Inner Niger Delta Using GIEMS and MODIS Data. In: JOURNAL OF HYDROMETEOROLOGY, 15 (1). pp. 171-192.

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Abstract

The objective in this work is to develop downscaling methodologies to obtain a long time record of inundation extent at high spatial resolution based on the existing low spatial resolution results of the Global Inundation Extent from Multi-Satellites (GIEMS) dataset. In semiarid regions, high-spatial-resolution a priori information can be provided by visible and infrared observations from the Moderate Resolution Imaging Spectroradiometer (MODIS). The study concentrates on the Inner Niger Delta where MODIS-derived inundation extent has been estimated at a 500-m resolution. The space-time variability is first analyzed using a principal component analysis (PCA). This is particularly effective to understand the inundation variability, interpolate in time, or fill in missing values. Two innovative methods are developed (linear regression and matrix inversion) both based on the PCA representation. These GIEMS downscaling techniques have been calibrated using the 500-m MODIS data. The downscaled fields show the expected space-time behaviors from MODIS. A 20-yr dataset of the inundation extent at 500 m is derived from this analysis for the Inner Niger Delta. The methods are very general and may be applied to many basins and to other variables than inundation, provided enough a priori high-spatial-resolution information is available. The derived high-spatial-resolution dataset will be used in the framework of the Surface Water Ocean Topography (SWOT) mission to develop and test the instrument simulator as well as to select the calibration validation sites (with high space-time inundation variability). In addition, once SWOT observations are available, the downscaled methodology will be calibrated on them in order to downscale the GIEMS datasets and to extend the SWOT benefits back in time to 1993.

Item Type:	Journal Article
Publication:	JOURNAL OF HYDROMETEOROLOGY
Publisher:	AMER METEOROLOGICAL SOC
Additional Information:	copyright for this article belongs to AMER METEOROLOGICAL SOC, 45 BEACON ST, BOSTON, MA 02108-3693 USA
Keywords:	Principal components analysis; Rivers; Interpolation schemes; Remote sensing; Land surface
Department/Centre:	Division of Mechanical Sciences > Civil Engineering
Date Deposited:	22 May 2014 07:59
Last Modified:	22 May 2014 08:02
URI:	http://eprints.iisc.ac.in/id/eprint/48869

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