The offline version version of SURFEX coupled to the operational ALADIN forecast over Belgium: a tool to improve winter screen temperature
Earth and related Environmental sciences
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In this study a state-of-the-art surface onldy model (SURFEX) is used offline in order to remove the positive feedbacks between the surface and the atmosphere in stable situations. The coupling occurs at ALADIN's lowest vertical level. Variables that must be exchanged are forecasted: air temperature, specific humidity, atmospheric pressure, incoming global radiation, incoming longwave radiation, precipitation rate and wind speed. The purpose of this note is to compare the offline diagnostic of screen temperature by SURFEX with the operational ALADIN forecast during the cool season (20072008). Results show a cyclic dependence of the ALADIN errors on the forecast range with large systematic error during the night. This indicates that the ALADIN errors occurs during cold winter night which is in agreement with the findings in the note of Termonia (2001). This underestimation of the winter minimum screen temperature is largely reduced by SURFEX except for January 2008 which is an exceptionally warm month. However, SURFEX seems to overestimate the screen temperature in very stable situations but the occurrence of these situations is marginal.
CitationHamdi, R. (2009). The offline version version of SURFEX coupled to the operational ALADIN forecast over Belgium: a tool to improve winter screen temperature. , Issue 0, 1/24/2015, IRM,