Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 13 9 2009 10.5194/hess-13-1749-2009 http://www.hydrol-earth-syst-sci.net/13/1749/2009/ http://www.hydrol-earth-syst-sci.net/13/1749/2009/hess-13-1749-2009.html http://www.hydrol-earth-syst-sci.net/13/1749/2009/hess-13-1749-2009.pdf 1749 1756 2009-09-30 A qualitative description of shallow groundwater effect on surface temperature of bare soil F. Alkhaier khaier@itc.nl R. J. Schotting Z. Su Department of water resources, International Institute for Geo-information Science and Earth Observation, Enschede, The Netherlands Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands Whether or not shallow groundwater affects skin temperature (the temperature of soil surface) is important to detect depth and extent of shallow groundwater by dint of remote sensing and important for land surface modelling studies. Although few studies have been conducted to investigate that effect, they have yielded contradicting conclusions and they stopped in 1982. To determine that shallow groundwater affects skin temperature, we measured soil temperature at two different depths (5 and 10 cm) in seven places with variable water table depths every ten minutes and for six days. After that, we correlated the minimum, maximum and average daily temperatures to average groundwater depth. We also built a simple numerical model using a differential equations solver, Flex PDE, to simulate heat transfer into soil profile and used it to simulate groundwater effect on skin temperature. We found quite high negative correlation between the maximum and average daily soil temperature and groundwater depth. Contrarily, we could hardly find any correlation between the daily minimum temperature and groundwater depth. 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