Air temperature in high temporal and spatial resolution from a combination of the SEVIRI and MODIS instruments

Abstract

Some applications e.g. from traffic management or energy meteorology require air temperature at 2 metres height above the ground in a high spatial and temporal resolution, partly even in near-real-time. Thus a parameterization based on boundary layer physical principles, which determines air temperature from remote sensing data (SEVIRI data aboard the MSG and MODIS data aboard Terra and Aqua satellites), was developed. The method consists of two parts. First, a downscaling procedure from the SEVIRI pixel resolution of several kilometres to one kilometre spatial resolution is performed using a regression analysis between the land surface temperature (LST) and normalized differential vegetation index (NDVI) acquired by the MODIS instrument. Secondly, the data as albedo, downwelling surface short- and long-wave fluxes, relief characteristics and NDVI data are used as input parameters in the empirical parameterization that removes the lapse rate between LST and 2 m air temperature. The method was successfully tested for Slovenia, the French region Franche-Comté and southern Germany in May to December 2005 allowing the development of a parameterization valid for central Europe. This parameterisation results in a RMSD of 2.0 K during daytime with a bias of -0.01 K and a correlation coefficient of 0.95. This is a promising result especially considering the high temporal (30 min) and spatial resolution (1000 m) of the results.