# Presentation: 829316

## Broadband Satellite-Like (Infrared) Cloud Products from NCEP Models and Preliminary Cloud VerificationB. Ferrier1,2, H.-Y. Chuang1,2, E. Rogers1, B. Zhou1,2, J. McQueen1, and G. DiMego1 1NOAA/NWS/NCEP/EMC2SAIC/GSOThanks also to P. Manousos (NWS/NCEP/HPC),K. Campana1, M. Hart1,2, and J. Hanna (NESDIS)

## 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, ********=5.67****·****10****-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)**

## Forecasts (left) & obs (right) @ 00Z 30 May 2006

**24-h** **WRF NMM forecasts**
-  **TOA total IR (top, left)**: colder Tb’s (atmos abs/emis)
-  **NCAR algorithm (bot, left)**:  warmer Tb’s

**0015 UTC**

## Forecasts (left) & obs (right) @ 00Z 30 May 2006

**12-h** **WRF NMM forecasts**
-  **TOA total IR (top, left)**:  colder Tb’s (atmos abs/emis)
-  **NCAR algorithm (bot, left)**:  warmer Tb’s

**0015 UTC**

## Forecasts (left) & obs (right) @ 12Z 29 May 2006

**Forecasts ****(left)**** & obs ****(right)**** @ 12Z 29 May 2006**

**24-h** **WRF NMM forecasts**
-  **TOA total IR (top, left)**:  colder Tb’s (atmos abs/emis)
-  **NCAR algorithm (bot, left):** warmer Tb’s

**1215 UTC**

## Forecasts (left) & obs (right) @ 12Z 29 May 2006

**Forecasts ****(left)**** & obs ****(right)**** @ 12Z 29 May 2006**

**12-h** **WRF NMM forecasts**
-  **TOA total IR (top, left):** colder Tb’s (atmos abs/emis)
-  **NCAR algorithm (bot, left)**: warmer Tb’s

**1215 UTC**

## 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**_**[http://wwwt.emc.ncep.noaa.gov/mmb/mmbpll/nampll12_fullcyc_2mbtop/](http://wwwt.emc.ncep.noaa.gov/mmb/mmbpll/nampll12_fullcyc_2mbtop/)**_
**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**

## 32-km Grid 221 vs. full NAM domain (Eta-12)

## Preliminary Cloud Verification

**Objective verification using NCEP’s **_**F**_**orecast **_**V**_**erification ****S****ystem (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**
_**Cl**_**ouds from **_**AV**_**H**_**R**_**R (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**

## 12-km Grid 218 vs. full NAM domain (Eta-12)

## 12Z NAM (Ops Eta) vs. AFWA, CLAVR

**1200 UTC 23 March – 1200 UTC 15 May 2006**

** ****Smallest NAM biases at midday (18Z), largest in early morning**
** ****Closer agreement (smaller errors) with CLAVR**

## Time Series of 48-h NAM and WRF NMM Cloud Forecasts

**1200 UTC 23 March – 1200 UTC 15 May 2006**

** ****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?)**

## Model Biases as Functions of Cloud Fraction

**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)**

** ****Almost 50% high bias in****  overcast conditions**
** ****Dominated by low clouds****  (esp over oceans; not shown)**

## 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)**

## 18-h FCST  vs.  GOES Retrieved (SW↓)sfc