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Physics, Atmospheric and Oceanic Physics, physics.ao-ph
Abstract:
High resolution information of climatic conditions is essential to many
application in environmental sciences. Here we present the CHELSA algorithm to
downscale temperature and precipitation estimates from the European Centre for
Medium-Range Weather Forecast (ECMWF) climatic reanalysis interim (ERA-Interim)
to a high resolution of 30 arc sec. The algorithm for temperature is based on a
statistical downscaling of atmospheric temperature from the ERA-Interim
climatic reanalysis. The precipitation algorithm incorporates orographic
predictors such as wind fields, valley exposition, and boundary layer height,
and a bias correction using Global Precipitation Climatology Center (GPCC)
gridded and Global Historical Climate Network (GHCN) station data. The
resulting data consist of a monthly temperature and precipitation climatology
for the years 1979-2013. We present a comparison of data derived from the
CHELSA algorithm with two other high resolution gridded products with
overlapping temporal resolution (Tropical Rain Measuring Mission (TRMM) for
precipitation, Moderate Resolution Imaging Spectroradiometer (MODIS) for
temperature) and station data from the Global Historical Climate Network
(GHCN). We show that the climatological data from CHELSA has a similar accuracy
to other products for temperature, but that the predictions of orographic
precipitation patterns are both better and at a high spatial resolution.
