WATCH Project News PhD position on Soil Moisture Remote Sensing Estellus (partner of WATCH-member organisation LMD) is a very young spin-up emerging from public research institutes in Paris, France, in the field of satellite remote sensing of Earth’s surface and atmosphere. Estellus is offering a PhD position on Soil Moisture Remote Sensing. Estellus, March 09, 2010 WATCH Technical Report Number 22: The WATCH forcing data 1958-2001: a meteorological forcing dataset for land surface- and hydrological-models New global sub-daily meteorological forcing data are provided for use with landsurface-and hydrological-models. The data are derived from the ERA-40 reanalysis product via sequential interpolation to half-degree resolution, elevation correction and monthly-scale adjustments based on CRU (corrected-temperature, diurnal temperature range, cloud-cover) and GPCC (precipitation) monthly observations combined with new corrections for varying atmospheric aerosol-loading and separate precipitation gauge corrections for rainfall and snowfall. Weedon, G.P., Gomes, S., Viterbo, P., Österle, H., Adam, J.C., Bellouin, N.,Boucher, O., and Best, M., February 26, 2010 WATCH Paper "Feedbacks on Convection from an African Wetland" in press with Geophysical Research Letters The Niger Inland Delta in Mali floods every year in response to rain falling hundreds of kilometers upstream. This study examines the remote hydrological feedback between rainfall, fluvial inundation, and new convective storms. A satellite thermal infra-red dataset spanning 24 years is used to quantify both temporal variability in
wetland extent, and the response of cloud cover to the wetland during August and September. The daytime initiation of convective storms is found to double during periods of inundation, consistent with a hypothesised “wetland breeze” effect. A signal of enhanced cloud cover propagates hundreds of kilometers westwards, linked to increased numbers of long-lived Mesoscale Convective Systems emanating from the wetland region. This effect raises the possibility that changes in upstream water use could have a climatic impact over a wide area. Geophysical Research Letters , February 01, 2010 -
Training course: Classifications in atmospheric sciences and their applications, University of Augsburg, 12-16 April 2010 The objective of this course is to give the students an introduction to classification methods, with emphasis on classifications of tropospheric circulation patterns, and their applications in the atmospheric sciences, and to provide a basis to understand the various classification methods applied to describe atmospheric circulation. Deadline for applications is 28 February. This event will contribute to the Milestone M4.1-8 "Workshop on climate drivers" that contribute to Task 4.1.6. WATCH Secretary, January 18, 2010 WATCH Technical Report Number 20: Hydrological drought characteristics of the Nedožery sub catchment, Upper Nitra, Slovakia, based on HBV modelling A River Basin Hydrological Model (RBHM) using HBV has been developed for the Nedožery catchment, Upper Nitra (Slovakia), which is a a focal area in the WATCH Test Basin Upper-Nitra (Slovakia). The hydrological regime of the Nedožery catchment is affected by snow, in particular in the headwaters. It is a fast-responding catchment (crystalline rocks). The model has been tested against time series of observed river flow, groundwater levels and snow. Trend analysis on the model input data showed downward trends in the observed discharge and upward trends in the observed precipitation and the annual number of snow days, which resulted in an over- (1974-1990) and underestimation (1991-2006) of the observed discharge. Time series of observations and outcome from the models were used to identify different drought types (meteorological drought, hydrological drought). Hydrological droughts (both winter and summer) in Nedožery catchment develop due to above average temperatures combined with below average precipitation. In winter this leads to a below average snow cover (resulting in lower spring discharges) and the occurrence of above average evapotranspiration. In winter, hydrological drought can also be caused by below average temperature, because water is stored on the surface as snow for a longer period. Such a winter drought does not continue into summer, because it ends by above average snowmelt in spring. HBV’s results were compared with outcome from the lumped, conceptual hydrological model BILAN and the distributed, physically-based hydrological model FRIER to test the impact of model structure on drought assessment. The BILAN model gives a lower number of droughts which are longer as compared with HBV. Recession curves simulated with BILAN are long and response on precipitation events during the recession is almost invisible. FRIER output shows more, but shorter droughts which indicates FRIER reacts faster to precipitation than HBV and BILAN. The RBHM and the outcome will be used in the WATCH project: (1) to develop a generic method for drought propagation, (2) to test the usefulness of large-scale forcing data (WATCH Forcing Dataset), and (3) to test the ability of large-scale land surface models (LSHMs) and global hydrological models (GHMs) to capture droughts. Jacob Oosterwijk, Anne F. van Loon, Andrej Machlica, Oliver Horvát, Henny A.J. van Lanen & Miriam Fendeková, December 28, 2009
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