D27 Report on MM5 GPSPW nudging
This report is part of work-package 4200, the purpose of which is
* Development of GPS ZTD assimilation software for the 3DVar assimilation
system for the mesoscale NWP model MM5.
* Investigate the impact of assimilation of GPS PW into the MM5 at high resolution
using different assimilation techniques: nudging and 3DVAR.
Methodology/Work Description: Recent work showed the impact of the
assimilation of GPS precipitable water (PW) into high resolution weather
forecasts (Faccani et al., in preparation) for a few cases using the
nudging technique. It is desirable to test this technique operationally and
compare it with a more accurate assimilation technique such as 3DVAR. Therefore,
during the first period the GPS PW will be assimilated through nudging, in
the mean time the 3DVAR system will be implemented and the assimilation will
be carried out using the 3DVAR only. A comparison with the nudging will be
performed for a few selected cases. The GPS ZTD assimilation technique will
be developed for fully operational use.
The results of the MM5 GPSPW nudging experiments are available in an article:
Near real-time data assimilation of GPS ZTD and PW
into a non-hydrostatic model