NHESS Natural Hazards and Earth System Sciences NHESS Nat. Hazards Earth Syst. Sci. 1684-9981 Copernicus Publications Göttingen, Germany 10.5194/nhess-10-121-2010 Water vapour distribution at urban scale using high-resolution numerical weather model and spaceborne SAR interferometric data Pichelli E. 1 Ferretti R. 1 Cimini D. 1 Perissin D. 2 Montopoli M. 4 1 Marzano F. S. 3 1 Pierdicca N. 3 Department Physics, University of L'Aquila/CETEMPS, L'Aquila, Italy Institute of Space and Earth Information Science, Chinese University of Hong Kong, Hong Kong, China Department Electronic Engineering, Sapienza University of Rome, Rome, Italy Department of Electrical and Information Engineering, University of L'Aquila, L'Aquila, Italy 22 01 2010 10 1 121 132 Copyright: © 2010 E. Pichelli et al. 2010 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://nhess.copernicus.org/articles/10/121/2010/nhess-10-121-2010.html The full text article is available as a PDF file from https://nhess.copernicus.org/articles/10/121/2010/nhess-10-121-2010.pdf

The local distribution of water vapour in the urban area of Rome has been studied using both a high resolution mesoscale model (MM5) and Earth Remote Sensing-1 (ERS-1) satellite radar data. Interferometric Synthetic Aperture Radar (InSAR) techniques, after the removal of all other geometric effects, estimate excess path length variation between two different SAR acquisitions (Atmospheric Phase Screen: APS). APS are strictly related to the variations of the water vapour content along the radar line of sight. To the aim of assessing the MM5 ability to reproduce the gross features of the Integrated Water Vapour (IWV) spatial distribution, as a first step ECMWF IWV has been used as benchmark against which the high resolution MM5 model and InSAR APS maps have been compared. As a following step, the high resolution IWV MM5 maps have been compared with both InSAR and surface meteorological data. The results show that the high resolution IWV model maps compare well with the InSAR ones. Support to this finding is obtained by semivariogram analysis that clearly shows good agreement beside from a model bias.

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