Transcript RUC.ppt
Rapid Update Cycle-RUC RUC • A major issue is how to assimilate and use the rapidly increasing array of offtime or continuous observations (not a 00 and 12 UTC world anymore! • Want very good analyses and very good shortterm forecasts (1-3-6 hr) • The RUC ingests and assimilates data hourly, and then makes short-term forecasts • Uses the MAPS mesoscale model…which uses a hybrid sigma/isentropic vertical coordinate • Resolution: 13 km and 50 levels Domain 13km RUC Terrain elevation - 100 m interval Observations used in RUC Data Type ~Number Freq. -------------------------------------------------Rawinsonde 80 /12h NOAA profilers 30 / 1h VAD winds 110-130 / 1h Aircraft (V,temp) 1400-4500 / 1h Surface/METAR 1500-1700 / 1h Buoy/ship 100-150 / 1h GOES precip water 1500-3000 / 1h GOES cloud winds 1000-2500 / 1h GOES cloud-top pres 10 km res / 1h SSM/I precip water 1000-4000 / 6h -------------------------------------------------GPS precip water ~300 / 1h Mesonet ~5000 / 1h METAR-cloud-vis-wx ~1500 / 1h -------------------------------------------------- RUC History – NCEP (NMC) implementations 1994 - First operational implementation of RUC - 60km resolution, 3-h cycle 1998 – 40km resolution, 1-h cycle, - cloud physics, land-sfc model 2002 – 20km resolution - addition of GOES cloud data in assimilation 2003 – Change to 3dVAR analysis from previous OI (April) 2004 – Vertical advection, land use (April) PBL-depth for surface assimilation (September) 2005 – 13km resolution, new obs, new model physics (June) 2011 – WRF-based Rapid Refresh w/ GSI to replace RUC WRF RUC • A new version of RUC has been developed, that uses the WRF model instead of the MAPS model. Called the Rapid Refresh. Now running, will replace RUC this year. Rapid Refresh: 13 km but larger domain High-Resolution Rapid Refresh: 3 km, 1 hr, smaller domain RTMA (Real Time Mesoscale Analysis System) NWS New Mesoscale Analysis System for verifying model output and human forecasts. RTMA • Downscales a short-term forecast to fine-resolution terrain and coastlines and then uses observations to produce a fine-resolution analysis. • Performs a 2-dimensional variational analysis (2d-var) using current surface observations, including mesonets, and scatterometer winds over water, using short-term forecast as first guess. • Provides estimates of the spatially-varying magnitude of analysis errors • Also includes hourly Stage II precipitation estimates and Effective Cloud Amount, a GOES derived product • Either a 5-km or 2.5 km analysis. RTMA • The RTMA depends on a short-term model forecast for a first guess, thus the RTMA is affected by the quality of the model's analysis/forecast system • CONUS first guess is downscaled from a 1hour RUC forecast. • Because the RTMA uses mesonet data, which is of highly variable quality due to variations in sensor siting and sensor maintenance, observation quality control strongly affects the analysis. Why does NWS want this? • Gridded verification of their gridded forecasts (NDFD) • Serve as a mesoscale Analysis of Record (AOR) • For mesoscale forecasting and studies. RTMA 2dVAR update RUC-RTMA downscaling 22 to detailed RTMA background RTMA 2dVAR update RUC-RTMA downscaling 23 to detailed RTMA background TX 2 m Temperature Analysis 24 TX 2 m Temperature Analysis 25 TX 2 m Temperature Increment 26