4 th JCSDA Science Workshop, 31 May 1 June 2006 Broadband Satellite-Like (Infrared) Cloud Products from NCEP Models and Preliminary Cloud Verification B. Ferrier 1,2, H.-Y. Chuang 1,2, E. Rogers 1, B. Zhou 1,2, J. McQueen 1, and G. DiMego 1 1 NOAA/NWS/NCEP/EMC 2 SAIC/GSO Thanks also to P. Manousos (NWS/NCEP/HPC), K. Campana 1, M. Hart 1,2, and J. Hanna (NESDIS) 4 th JCSDA Science Workshop, 31 May 1 June 2006 Background on Satellite Cloud Products Project motivation Interest in forecast satellite look-a-like clouds by Hydrologic Prediction Center (HPC) and NWS Eastern Region Such products already produced by CMC & U. Wisconsin 2 simple infrared (IR) algorithms in WRF Nonhydrostatic Mesoscale Model (WRF NMM to replace Eta on June 13) Brightness temperature (T b ) from TOA outgoing longwave fluxes (= *T b 4, =1, =5.6710 -8 W m -2 K -1 ; Stefan-Boltzman Law ) WRF NMM, NAM use GFDL LW radiation (85, 91), modified by Global Branch (Hou et al.) NCAR algorithm (Stoelinga) starting from TOA find air temperature at cloud optical depth of = 1 (using cloud emissivities in model) 4 th JCSDA Science Workshop, 31 May 1 June 2006 Forecasts (left) & obs 00Z 30 May h WRF NMM forecasts TOA total IR (top, left): colder T b s (atmos abs/emis) NCAR algorithm (bot, left): warmer T b s 0015 UTC 4 th JCSDA Science Workshop, 31 May 1 June 2006 Forecasts (left) & obs 00Z 30 May h WRF NMM forecasts TOA total IR (top, left): colder T b s (atmos abs/emis) NCAR algorithm (bot, left): warmer T b s 0015 UTC 4 th JCSDA Science Workshop, 31 May 1 June 2006 Forecasts (left) & obs 12Z 29 May h WRF NMM forecasts TOA total IR (top, left): colder T b s (atmos abs/emis) NCAR algorithm (bot, left): warmer T b s 1215 UTC 4 th JCSDA Science Workshop, 31 May 1 June 2006 Forecasts (left) & obs 12Z 29 May h WRF NMM forecasts TOA total IR (top, left): colder T b s (atmos abs/emis) NCAR algorithm (bot, left): warmer T b s 1215 UTC 4 th JCSDA Science Workshop, 31 May 1 June 2006 Final Remarks on Cloud Products TOA IR and NCAR IR cloud-top will be available in 32-km grid 221 files (next slide) Can be viewed from our parallel WRF NMM runs (NAMX, NAMY) from the past week at Jump link TOA Brightness Temperatures (left frame) More improvements needed before use in operations at HPC and WFOs More accurate narrowband calculations Use CRTM in our unified (regional, global) post processing for multiple frequencies (e.g. water vapor) JCSDA funding would accelerate pace of effort 4 th JCSDA Science Workshop, 31 May 1 June km Grid 221 vs. full NAM domain (Eta-12) 4 th JCSDA Science Workshop, 31 May 1 June 2006 Preliminary Cloud Verification S Objective verification using NCEPs Forecast Verification System (FVS) Typical verification uses values of model grid points at observation points (grid-to-obs verification) Expanded to verify model grids using analysis grids (grid-to-grid verification) AFWA total cloud cover product Clouds from AVHRR (CLAVR) total cloud cover Validation over 12-km grid 218 (next slide) Focus mostly on operational NAM (Eta), but also show preliminary results from WRF NMM 4 th JCSDA Science Workshop, 31 May 1 June km Grid 218 vs. full NAM domain (Eta-12) Verification 4 th JCSDA Science Workshop, 31 May 1 June Z NAM (Ops Eta) vs. AFWA, CLAVR 1200 UTC 23 March 1200 UTC 15 May 2006 RMSE (%) CLAVR AFWA Time (UTC) Forecast Hour Bias (%) Time (UTC) Forecast Hour Smallest NAM biases at midday (18Z), largest in early morning Closer agreement (smaller errors) with CLAVR 4 th JCSDA Science Workshop, 31 May 1 June 2006 Time Series of 48-h NAM and WRF NMM Cloud Forecasts 1200 UTC 23 March 1200 UTC 15 May 2006 RMSE (%) Missing WRF NMM Runs MarchAprilMay Bias (%) NAM - AFWA NAM - CLAVR WRF NMM - AFWA WRF NMM - CLAVR MarchAprilMay Both models agree more closely with CLAVR Both models have a high bias in total cloudiness WRF NMM has a higher cloud bias than NAM (low clouds?) 4 th JCSDA Science Workshop, 31 May 1 June 2006 Model Biases as Functions of Cloud Fraction Threshold Cloud Fraction (%) Area Bias (Model / Analysis) 23 March - 15 May 2006 Forecast-Hit-Observation (FHO) stats (48-h forecasts valid at 12Z) FCST OBS HIT Almost 50% high bias in overcast conditions Dominated by low clouds (esp over oceans; not shown) NAM - AFWA NAM - CLAVR WRF NMM - AFWA WRF NMM - CLAVR 4 th JCSDA Science Workshop, 31 May 1 June 2006 Final Remarks on Cloud Verification Models tend to predict too much cloudiness compared to AFWA, CLAVR analyses Better agreement during midday, worse agreement during early morning hours Models compare more favorably to CLAVR Slightly higher bias in WRF NMM cloudiness compared to NAM-Eta (esp. for AFWA at 12Z, less so for CLAVR) Largest over prediction in overcast conditions JCSDA funding would also accelerate pace and scope of development to include more models and verifying analyses (next slide as an example) 4 th JCSDA Science Workshop, 31 May 1 June h FCST vs. GOES Retrieved (SW) sfc Useful for quick sanity checks of forecast incoming surface solar Thanks to Istvan Laszlo (NESDIS) for providing 18Z images online, and to K. Mitchell, D. Tarpley Ops Eta WRF NMM