Michael Bender, Deutscher Wetterdienst (DWD)
GPS Slant Delay Assimilation for Convective Scale NWP
CoauthorsKlaus Stephan, Christoph Schraff, Hendrik Reich, Andreas Rhodin, Roland Potthast
Abstract: Atmospheric delays of GPS signals provide information about the structure of
the atmosphere, especially the water vapor distribution.
A slant total delay
(STD) assimilation operator was developed at the German Weather Service (DWD)
to assimilate STD and ZTD (zenith total delay) observations into the numerical
weather models. A pre-operational version of the ensemble Kalman filter for
convective scale data assimilation (KENDA) was used to run the COSMO-DE local
model together with the STD assimilation operator. Hourly COSMO-DE forecasts
of 40 ensemble members were processed by the local ensemble transform Kalman
filter (LETKF) to obtain the analyses and 24-hour forecasts were started every 6
hours. First STD assimilation experiments show a positive impact and some
initial results will be presented.