Application of satellite observations for the evaluation of the land surface temperature from GEM model forecast
Abstract: The Global Environmental Multiscale model (GEM) was evaluated against satellite observations and measurements from synoptic stations. The computational grid was set up in the global variable mode with the resolution of ~25 km over Central Europe. Model evaluation was performed over Central Europe within a window of 43-56°N latitude and 10-25°E longitude. Surface temperature forecasts were compared with the Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature product. Air temperature measured at the height of 2 metres was obtained from about 480 synoptic stations from 13 Central Europe countries. Air temperature measurements collected at 9 UTC and 12 UTC during five days (31 January, 2 February, 3 March, 27 April and 18 June 2012) was compared with the GEM model results. Evaluation showed good agreement between modelled and observed data. In case of air temperature, the averaged value of the Mean Bias Error (MBE) was -0.42, the averaged Root Mean Square Error (RMSE) and the Mean Absolute Gross Errors (MAGE) were 3.21 and 2.32, respectively. Land surface temperature comparisons gave results of -2.01; 3.91 and 3.24 of the (MBE), (RMSE), and (MAGE), respectively. Also, correlation of derived modelling errors between surface temperature and air temperature are discussed. In each case the correlation coefficient was positive. The highest value (0.70) was obtained for periods when surface – atmosphere radiative exchange processes were dominant.
Keywords: MODIS; surface temperature; model evaluation
Area: Environmental Sciences