In a collaborative effort among the University of Hawaii,
NCEP and NWSFO-HNL, the hydrostatic version of the Regional Spectral
Model (RSM) (Juang and Kanamitsu, 1994) with 10-km resolution was
implemented in early 1997 into the operational runstream for the state
of Hawaii by NCEP (Wang et al. 1998). Nevertheless, the mountainous
terrain of the Hawaiian islands causes large spatial variabilities
in local weather which can not be adequately resolved by the 10-km grid
of the RSM. Furthermore, large variations in local microclimate
ranging from humid tropical climate on the windward lower slopes to
hot desert over bare lava soils with different surface vegetation cover
calls for the implementation of an advanced Land Surface Model (LSM)
to better represent surface conditions.
Kodama and Juang (1999) evaluated the performance of the RSM forecasts during the 1997 warm (May-September) season against the AVN for four surface sites (Hilo, Lihue, Kahului, and Honolulu). Verification statistics show that the RSM outperformed the AVN at Hilo on the island of Hawaii and Lihue on the island of Kauai but not Kahului on the island of Maui and Honolulu on the island of Oahu. The disappointing results at Kahului and Honolulu are likely caused by the poor representation of the local topography for these two sites.
The primary objectives of this project are (1) to apply the NCEP high resolution (<3 km) nonhydrostatic mesoscale spectral model (MSM) (Juang 1992; Juang et al. 1997; Juang 2000) to improve weather forecasting, especially for high winds and heavy rainfall events, over the Hawaiian islands, and (2) to couple an advanced Land Surface Model (LSM) with improved surface boundary conditions into the RSM and MSM. The MSM has been installed on the Dec AlphaServer ES40 with 4 EV67 CPUs at the Department of Meteorology, University of Hawaii. The MSM is set up for three regions of the state of Hawaii: 3-km resolution for the Hawaii-Maui-Molokai domain, 1.5-km for the Oahu domain and 1.5-km for the Kauai domain (Chen et al. 1999, Zhang et al. 2000).