Monday, 8 June 2009: 4:10 PM
Pinnacle A (Stoweflake Resort and Confernce Center)
We describe a prototype of the Navy's global numerical weather (NWP) prediction system that extends through the mesosphere and lower thermosphere (MLT). The few such ground-to-MLT NWP prototypes that currently exist have to date been run in modes that only assimilate the standard tropospheric and stratospheric observations typically also assimilated by their low-altitude operational counterparts, so that the MLT components run free of any local data assimilation constraint. Here we perform runs with our system that for the first time assimilate, in addition to the regular complement of operational METOC data, high-altitude measurements (30-95 km) of temperature, water vapor and ozone from the MLS and SABER instruments on the Aura and TIMED satellites, respectively. We focus initially on the 6 hourly data-constrained global assimilation fields at the new MLT altitudes. These high-latitude summer MLT analyses are compared to PMC-related observations from the AIM and STP-Sat1 satellites and to sporadic NLC outbreaks observed from the ground. The assimilated MLT fields prove especially promising in specifying realistic tidal and fast planetary wave signals, an historically thorny issue in the MLT given the limited amounts of asynoptic MLT satellite observations available for such studies. Preliminary statistical properties of short-term global MLT forecasts constrained by these global ground-to-MLT atmospheric initial conditions are described. Our findings point to the important role of both resolved and parameterized gravity wave drag in the MLT components of these emerging systems.
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