# Presentation: 919834

## Air-Sea Fluxes in NCEP’s Seasonal Forecast Model

**Glenn White**
**Global Climate and Weather Modeling Branch**
**EMC/NCEP/NWS/NOAA**
**Dept. of Commerce**
**Camp Springs, MD**
- Glenn.White@noaa.gov

## Thanks to 

**Suru Saha**
**Wanqui Wang**
**Hua-Lu Pan**
**S. Moorthi**
**John Janowiak**
**Global Climate and Weather Modeling Branch**
**Climate Prediction Center**

## Global Climate and Weather Modeling Branch responsible for improving operational global numerical weather prediction of weather and climate.

**Weather**
**--3-7 day forecasts**
**--aviation, hurricane forecasts**
**--week-2 forecasts**
**Data assimilation crucial.**
**SST observed, anomalies damped to climatology in forecasts**

## Branch currently unifying atmospheric models used for weather and climate

**--monthly, seasonal forecasts**
**--out to 7 months**
**--atmospheric model driven by SSTs forecast by coupled atmospheric-ocean system**

***Branch currently unifying atmospheric models used for weather and climate***

## Wind stress of particular interest 

**- direct measure of physical interaction between atmosphere and ocean.**
**-good diagnostic of model’s parameterization of boundary layer, radiation and cloudiness**
**-essential for coupling atmosphere and ocean models**

**Wind stress of particular interest***** ***

## Validation

**T62 version of model  to be implemented in GFS next week for weather**
**28 levels vs.  64 levels**

**Validation**
**Southampton Oceanography Centre COADS-based climatology 1980-93**
**FSU wind stress 1978-2000**
**SRB-1 surface radiation (NASA Langley) 1985-91**
**NCEP 1 and 2 reanalyses**
**CMAP precipitation **

## Reanalyses have problems with surface radiative fluxes.

**—****cloudiness and moisture poorly known and modeled.**
**Reanalyses’  sensible and latent heat and wind stress are more realistic.**
**--Parameterizations dependent on near-surface fields, which NWP data assimilation can handle.**

## Global Ocean Surface Energy Budget

***Global Ocean Surface Energy Budget***

***Ocean Heat Budget Closure Problem (Josey et al., 1999)***
**COADS-based fluxes don’t add up**
**SRB NLW  extreme, NSW too high? Large net radiation in SRB**

## Coupled Modeling Requires Atmospheric Model With Realistic Fluxes We Don’t Know Reality Accurately Enough To Calibrate Model Physics For NWP

## 5S-5N

**5S-5N**

**Pacific FSU**

**1980-93 SOC**

**Time-mean**
**U****s**

## SOC

**Annual Cycle**

**1980-93**

**Pacific**

**SOC**

**FSU**

## CDAS

**CDAS**

**NCEP2**

## 28 levels

**28 levels**

**64 levels**

## 28 levels-NCEP2

**28 levels-NCEP2**

**64-NCEP2**

## FSU

**JJA 1980-93 Time mean zonal wind stress**

**FSU**

**28**

**64**

## Anomaly correlation with FSU--Pacific

**Anomaly correlation with FSU--Pacific**

**CDAS**

**NCEP2**

**28 levels**

**64 levels**

**Zonal wind stress**

## FSU

**FSU**

**Standard deviation of monthly anomalies**

**28 levels**

**64 levels**

**1979-2000**

## EVAPORATION

***EVAPORATION***

***ZONAL MEAN OVER OCEAN***

**1980-93**

***SOC Climatology***

## SFC NSW

**SFC NSW**
**1985-91**

**SRB1**

**AMIP 28 levels**

**AMIP**
**64 levels**

## 28 levels minus SRB1

**Stratus displaced west by too much precip over land**

**28 levels minus SRB1**

**64 levels minus SRB1**

**Surface net short wave**

## Zonal mean net heat flux into ocean 1980-93

**Into ocean**

**Out of ocean**

**Zonal mean net heat flux into ocean 1980-93**

## Standard deviation of monthly means

**Standard deviation of monthly means**

**Zonal mean**
**1979-2001**

**Precipitation**

## Zonal mean anomaly correlation with CMAP 1979-2001

**Zonal mean anomaly correlation with CMAP 1979-2001**

**5S-5N**

## DJF 1979-2001

**DJF 1979-2001**

**CMAP**

**28**

**64**

***Precipitation***

## Need to improve knowledge of air-sea fluxes, especially magnitude of hydrological cycle, atmospheric moisture.

**Need to improve knowledge of air-sea fluxes, especially magnitude of hydrological cycle, atmospheric moisture.**
**64 levels improves precipitation, not wind stress, over 28 levels.**
**Cloudiness major problem in NWP fluxes.**
**New prognostic clouds need to be tuned.**

## SEAFLUX

**Report on our current knowledge of air-sea fluxes **
**Workshop proceedings**
**http://www.soc.soton.ac.uk/JRD/MET/WGASF**
**Or from WMO/WCRP**

**SEAFLUX**
**http://paos.colorado.edu/~curryja/ocean**

**SURFA—Peter Gleckler and Jan Polcher**
**Comparison of operational NWP centers’ **
**surface fluxes (land and ocean) to **
**high quality in-situ measurements**

***Work on air-sea fluxes***