85th AMS Annual Meeting

Wednesday, 12 January 2005
Soil moisture impacts on seasonal forecast predictability
Laurel L DeHaan, SIO/Univ. Of California, La Jolla, CA; and M. Kanamitsu, J. Roads, and C. H. Lu
The Experimental Climate Prediction Center (ECPC) has now incorporated the NCEP Noah land surface model (LSM) into the ECPC G-RSM (Global to Regional Spectral Model). The Noah LSM contains several enhancements to the previous LSM (OSU2) used in the G-RSM and the NCEP operational and reanalysis global spectral models. In fact, the Noah model was chosen for the recent NCEP regional reanalysis and details about the many LSM changes can be found on the regional reanalysis home page. It should be particularly noted that once the Noah modular model replaced the former OSU model, it became much simpler to incorporate additional LSMs. In that regard, the Univ. of Washington and Princeton University's Variable Infiltration Capacity (VIC) model is also now being incorporated as one of 3 G-RSM LSM options.

We have made an extensive number of simulations with the OSU and Noah LSMs. In particular, two 12-member GSM seasonal forecast ensembles (one using the OSU and one the Noah LSM) are now furnished to the IRI every month. These seasonal forecasts are initialized from 53-year, 10-member ensembles of forecasts forced by observed SSTs. In order to study the impact of soil moisture, additional members using the Noah climatological soil moisture will be compared to the fully interactive ensemble. Results will be presented at symposium.

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