April 2008 Christopher M. Hill Patrick J. Fitzpatrick Valentine G. Anantharaj Mississippi State University Lars-Peter Riishojgaard Global Modeling and Assimilation Office / NASA Joint Center for Satellite Data Assimilation An Observing System Simulation Experiment to Evaluate ATMS and CrIS Observations

General Overview component sensors of NPOESS and NPP to include:component sensors of NPOESS and NPP to include: –Advanced Technology Microwave Sounder ( ATMS ) across track scanning microwave radiometer cross-track resolution: 1.5 km –Cross-track Infrared Sounder ( CrIS ) Fourier transform spectrometer cross-track resolution: 14.0 km vertical resolution: ~ 3.0 km Combination of ATMS / CrIS designed to improve profiles of T and q OSSE with mesoscale models needed to assess the impact of ATMS / CrIS 2

3 MSU OSSE plan regional scale nature run (RSNR) using MM5regional scale nature run (RSNR) using MM5 –one-way nested grid set, with ICs and BCs from ECMWF NR data sensitivity experimentssensitivity experiments –use second model (WRF) to avoid similarity in model error (fraternal twin problem) –initial analyses tuned to model background errors 1)cold start simulation 2)assimilate synthetic surface, rawinsonde observations 3)assimilate data representing ATMS / CrIS use RTM to simulate sensor-observed radiance, assimilate derived T and q profilesuse RTM to simulate sensor-observed radiance, assimilate derived T and q profiles investigate NR-simulated squall line events at the U.S. coast of the Gulf of Mexicoinvestigate NR-simulated squall line events at the U.S. coast of the Gulf of Mexico

4 Case events identified from T799 NR (1°×1°) data May 2-4: squall line affecting all points along US Gulf coast May 7-8: decaying squall line over TXOct 10-11: squall line / tropical wave MSLP (hPa)3-h convective precipitation (mm) MSLP (hPa)3-h convective precipitation (mm). NASA portal accounts acquired this month Full resolution ECMWF T799 data being acquired Analysis of full resolution data in progress

Regional NR Image adopted from Shuttle Radar Topography Mission 5 ECMWF NR grid (global) WRF grid MM5 grid #1 MM5 grid #2 ICs and BCs from ECMWF NR dataICs and BCs from ECMWF NR data two MM5 grids; one WRF nesttwo MM5 grids; one WRF nest BCs perturbed across “buffer” grid #1BCs perturbed across “buffer” grid #1 imperfect BCs input to nested gridsimperfect BCs input to nested grids Grid #1 integration period O (weeks) to develop regional scale “truth”Grid #1 integration period O (weeks) to develop regional scale “truth” Grid #2, WRF grid integration period surrounding case events: hGrid #2, WRF grid integration period surrounding case events: h WRF used for sensitivity testsWRF used for sensitivity tests impact of CrIS / ATMS studied for NR-simulated squall lines along the Gulf coastimpact of CrIS / ATMS studied for NR-simulated squall lines along the Gulf coastMM5 grid #2 MM5 grid #1 ECMWF NR grid ECMWF BC WRF grid modified BC Houston / Galveston North Central Gulf Coast Tampa Bay region

Recently considered approach - Mesoscale NR WRF v3.0 global grid Global grid Initialized with ECMWF NR dataInitialized with ECMWF NR data New WRF global domain capabilityNew WRF global domain capability –assimilate global synthetic data –no boundary condition issue Integration periods surrounding case events:Integration periods surrounding case events: –27 September - 11 October –23 April - 08 May (2 case events) Regional nested grid broad domain centered over Gulfbroad domain centered over Gulf integration periods:integration periods: case event duration ( h) Images adopted from Shuttle Radar Topography Mission WRF regional grid extra