A great number of satellites monitor integrated water vapor (IWV) - the most important greenhouse gas in the Earth's atmosphere. We compare measurements of IWV by the satellite AMSU device and the ground-based microwave (MW) RPG-HATPRO radiometer in the vicinity of St. Petersburg (Peterhof) in the period between March 2013 and May 2014. Especially, we analyze the influence of spatial matching of two types of measurements. The minimal differences between ground-based and satellite measurements, both absolute, and relative, are observed at the minimal spatial mismatches (0-90 km). Moreover, the correlation coefficient between the two types of measurements decreases with the increase of spatial differences. The analysis of previous comparisons of IWV satellite MW measurements with independent data shows that the highest agreement of measurements is observed over the water surface. We explain this by the high accuracy of current parameterizations of MW water surface emissivity and the retrieval of its values from satellite measurement data.