Branch Seminar Series: Jonathan Case

Regional Atmospheric Modeling Specialist; NASA, Short-term Research Prediction and Transition (SPoRT) Center, NASA Marshal Space Flight Center and Senior Scientist/Meteorologist, ENSCO Inc.
This presentation compares daily regional simulations of the Weather Research and Forecasting (WRF) model initialized with high- resolution land surface information from the NASA Land Information System (LIS) software against a Control WRF configuration that uses land surface data from the National Centers for Environmental Prediction (NCEP) Eta model. Fifty-eight individual nested simulations were integrated 24 hours for both the Control and LISWRF experimental configurations during May 2004 over Florida and surrounding areas - 29 initialized at 0000 UTC and 29 initialized at 1200 UTC. The soil data for the LISWRF experiments came from an offline run of the Noah land surface model (LSM) within the LIS software for two years prior to the beginning of the month-long study. Atmospheric variables used to force the offline Noah LSM integration were provided by the North American Land Data Assimilation System and Global Data Assimilation System grid analyses. The LISWRF soil states were generally cooler and drier than the soil data provided by the NCEP Eta model. Comparisons between the Control and LISWRF runs from 6 May 2004 suggested that the LIS land surface initial conditions led to an improvement in the timing and evolution of a sea-breeze circulation over portions of northwestern Florida. Surface verification statistics calculated at 80 stations in the inner nested WRF domain with 3-km grid spacing indicated that the LISWRF runs produced a more accurate diurnal range in 2-m temperatures compared to the Control due to the overall drier initial soil states. This increased diurnal temperature range in LISWRF came from a reduction in the nocturnal warm bias in conjunction with a reduction in the daytime cold bias. Daytime LISWRF dew points were correspondingly drier than the Control dew points, again a manifestation of the drier initial soil states in LISWRF. Most other verified quantities indicated little to no improvement over the Control simulations.