Print Email Facebook Twitter Hydrotope-Based Protocol to Determine Average Soil Moisture Over Large Areas for Satellite Calibration and Validation With Results From an Observation Campaign in the Volta Basin, West Africa Title Hydrotope-Based Protocol to Determine Average Soil Moisture Over Large Areas for Satellite Calibration and Validation With Results From an Observation Campaign in the Volta Basin, West Africa Author Friesen, J. Rodgers, C. Oguntunde, P.G. Hendrickx, J.M.H. Van de Giesen, N. Faculty Civil Engineering and Geosciences Department Watermanagement Date 2008-05-16 Abstract In West Africa, which is an extremely moisturelimited region, soil water information plays a vital role in hydrologic and meteorologic modeling for improved water resource planning and food security. Recent and upcoming satellite missions, such as SMOS and MetOp, hold promise for the regional observation of soil moisture. The resolution of the satellites is relatively coarse (> 100 km2), which brings with it the need for large-scale soilmoisture information for calibration and validation purposes.We put forward a soil moisture sampling protocol based on hydrotopes. Hydrotopes are defined as landscape units that show internally consistent hydrologic behavior. This hydrotope analysis helps in the following ways: 1) by ensuring statistically reliable validation via the reduction of the overall pixel variance and 2) by improving sampling schemes for ground truthing by reducing the chance of sampling bias. As a sample application, we present data from three locations with different moisture regimes within the Volta Basin during both dry and wet periods. Results show that different levels of reduction in the overall pixel variance of soil moisture are obtained, depending on the general moisture status. With respect to the distinction between the different hydrotope units, it is shown that under intermediate moisture conditions, the distinction between t he different hydrotope units is highest, whereas extremely dry or wet conditions tend to have a homogenizing effect on the spatial soil moisture distribution. This paper confirms that well-defined hydrotope units yield an improvement at pixel-scale soil moisture averages that can easily be applied. Subject GeostatisticshydrotopesMetOPsatellitesscalingsoil moistureSoil Moisture and Ocean Salinity (SMOS)West Africa To reference this document use: http://resolver.tudelft.nl/uuid:1ee55b75-f64c-4fa7-aca5-fc015531be6f Publisher IEEE ISSN 0196-2892 Source IEEE Transactions on Geoscience and Remote Sensing, 46 (7) Part of collection Institutional Repository Document type journal article Rights (c) 2008 IEEE Files PDF friesen_2008.pdf 963.57 KB Close viewer /islandora/object/uuid:1ee55b75-f64c-4fa7-aca5-fc015531be6f/datastream/OBJ/view