# Presentation: 926327

## An Overview of New Developments with the NCEP Climate Forecast System

**SURANJANA SAHA**
**Environmental Modeling Center**
**NCEP/NWS/NOAA**
**20****th**** Annual Climate Diagnostics and Prediction Workshop**
**State College, PA**
**24 October 2005**

## ACKNOWLEDGEMENTS

**ACKNOWLEDGEMENTS**
**SCIENTISTS AND STAFF OF THE :**
**THE GLOBAL CLIMATE AND WEATHER MODELING BRANCH**
**ENVIRONMENTAL MODELING CENTER (EMC)**
**AND THE CONSIDERABLE HELP AND SUPPORT OF**
**CLIMATE PREDICTION CENTER (CPC)**
**AND**
**GEOPHYSICAL FLUID DYNAMICS LABORATORY (GFDL) **

##  The NCEP Climate Forecast System (CFS) was made operational in August 2004 

-  **The NCEP Climate Forecast System (CFS) ****was made operational in August 2004**** **
** ****Currently, two fully-coupled nine-month forecasts are made every day**
** ****The present CFS operational system at T62L64 resolution is frozen**
** ****Development work is underway at EMC to improve the CFS**
** ****We anticipate a new CFS implementation will take place in a few years**** **

## This is indeed an enormous challenge !!!

**For a new CFS implementation :**
** ****New upgrades to the CFS must lead to better performance**
**Retrospective forecasts with the new CFS, covering a period of nearly 30 years, will then have to be made**
**A global reanalysis of the atmosphere, land and ocean will have to be made, prior to that, to provide the initial conditions consistent with the new version of the CFS**
**This is indeed an enormous challenge !!!**

## TESTING CHANGES IN THE OCEAN PART OF THE CFS 

## NEW OCEAN MODEL MOM4 (GFDL)

**Jiande Wang**
**      ****Ocean-Only Simulation Run with MOM4**
**    ****1981-2004 R-2 Daily Forcing (heat flux, E-P). Same Resolution as operational MOM3, which has the following configuration :**
**    ****1/3 degree at equator, gradually decreasing to 1 degree at 30N and 30S. Northern boundary is at 65N and southern boundary is at 75S **
**    ****40 Vertical layers, 10 meter interval in the top 220 m Depth to 5.5 Km**

## Indonesian through flow is completely open in a larger area and the surrounding marginal seas are fully resolved as ocean (not land) points

**Indonesian through flow is completely open in a larger area and the surrounding marginal seas are fully resolved as ocean (not land) points**
**Use runoff data from NCAR (Dai and Trenberth)**
**Use real fresh water flux, instead of  “virtual salt flux”. This method gives more accuracy in the simulation of sea surface height**

## The bias everywhere is considerably less than with MOM3

**The bias everywhere is considerably less than with MOM3**

## NEW SEA ICE MODEL

**Xingren Wu**
**Thermodynamics : 3-layer  (Winton, 2000)**
**Dynamics : EVP Model (Hunke and Dukowicz, 1997)**
**The sea ice model was coupled to MOM4. **
**The model was forced using R-2 climatology**
**Sample results was for Year-20, March**

## Modeled sea ice thickness (Year-20, March)

**The simulated sea ice distribution is reasonable, **
**but sea ice thickness may be not thick enough**

## Sea ice concentration (Year-20, March)

**Sea ice concentration is just a little bit too high relative to the satellite observations**

**Model Simulation**

**Observations**

## Ocean Developmental work for the future 

**MOM4**
**Test higher horizontal resolution everywhere for MOM4 (****1⁄4** ** degree globally, or 1⁄4 degree in the tropics decreasing to 1⁄2 degree at 30N and 30S)**
**Increased number of vertical levels in the ocean mixed layer, from 40 to 50**
**Use new, more efficient, coupler, with more frequent coupling to the ocean (than the present once a day)**
**Include river (fresh water) runoff from climatology or NOAH land model**

## Global Ocean Data Assimilation (GODAS) :

** ****Explicit bias correction**
** ****Geostrophic balance in the assimilation**
** ****Altimetry and Argo salinity added to GODAS**

## TESTING CHANGES IN ATMOSPHERIC PART OF THE CFS 

## NOAH Land Model : 4 soil levels. Improved treatment of snow and frozen soil

**Sea Ice Model : Prediction of ice concentration and ice fraction**
**Sub grid scale mountain blocking **
**Reduced vertical diffusion**
**RRTM long wave radiation**

**TEST THE CURRENT OPERATIONAL VERSION OF THE GFS (USED FOR WEATHER PREDICTION)**
**UPGRADES**

## GFS Developmental work for the future 

**Test higher horizontal resolution (T126)**
**Test new convection scheme (RAS)**
**Test hybrid vertical coordinate (sigma-pressure, sigma-theta)**
**Test improved boundary layer physics**
**Test convectively forced gravity wave drag**
**Test new short wave radiation parameterization**

##    TWO KINDS OF STUDIES 

**CFS MONTHLY RETROSPECTIVE FORECASTS**
**CFS FREE COUPLED SIMULATIONS (CMIP)**

##    CFS WEEKLY AND MONTHLY FORECASTS

**Higher resolution, both spatial and temporal. **
**Spatial**** : T126L64 GFS Atmospheric model (as in   operational CFS) coupled to MOM3 Ocean Model**
**Temporal ****: 4 CFS runs daily : from 0Z,6Z,12Z and 18Z Atmospheric R2 initial conditions coupled to the same Ocean GODAS initial condition**
**Period**** : 2000 – 2004 (5 years)**
**Summer : 7 May – 15 July (70 days)**
**Winter    :  7 Nov – 15 Jan (70 days)**
**Integrations out to 65 days or more (covers the last full calendar month)**

## POSTER OF AUGUSTIN VINTZILEOS : 

**WEDNESDAY, 9-10:30 AM**
**THE CFS 126 : A DYNAMICAL SYSTEM FOR SUBSEASONAL FORECASTS – CHALLENGES IN PREDICTION THE MJO**
**U200 hPa forecasts averaged 20****°****S-20****°****N and projected to the MJO EOFs obtained from R2**

## Conclusions: Good skill and for the reasons that is shown in

**SUMMER**

**WINTER**

- 13 days

- 25 days

**Conclusions: ****Good skill and for the reasons that is shown in**
**                        ****the poster, we expect improvements....**

## POSTER OF HUA-LU PAN : 

**MONDAY, 9-10:30 AM**
**CLIMATE MODEL DIAGNOSES FROM A WEATHER MODELER’S POINT OF VIEW **
**V850 hPa forecasts and PRECIPITATION in the tropics from CFS retrospective forecasts and free coupled runs are examined**

## Conclusions: Episodic nature of easterly waves are well captured.

**Conclusions: ****Episodic nature of easterly waves are well captured.**
**                        ****Tropical disturbances in  the T126 are better simulated**

## POSTER OF ÅKE JOHANSSON : 

**TUESDAY, 9-10:30 AM**
**PREDICTION SKILL OF NAO AND PNA FROM DAILY TO SEASONAL TIME SCALES**
**Skill in predicting NAO and PNA indices (as deduced from geopotential at 500 hPa) from daily T126 and T62 retrospective forecasts for 5 winters (DJF 2000-2004) are examined, as well as the 24 winters of operational T62 CFS **

## Conclusions: There is lingering skill in both NAO and PNA out to 45 days, albeit small. PNA has higher skill than NAO in the short/medium range while NAO has higher skill than PNA in the intraseasonal time range

**Conclusions: ****There is lingering skill in both NAO and PNA out to 45 days, albeit small. PNA has higher skill than NAO in the short/medium range while NAO has higher skill than PNA in the intraseasonal time range**

**PNA**

**NAO**

## POSTER OF CATHERINE THIAW : 

**MONDAY, 9-10:30 AM**
**INDIAN SUMMER MONSOON PREDICTION IN THE NCEP CLIMATE MODEL**
**Using retrospective forecasts from 9-13 May, the CFS prediction of the onset of the Indian summer monsoon is examined, using the wind at 850 hPa, Precipitation and SST. **

## Conclusions: The overall prediction of the Indian monsoon rainfall is reasonable. The onset is a little late and the rainfall is a little weak. Higher horizontal resolution and better physics may lead to improvements

**Conclusions: ****The overall prediction of the Indian monsoon rainfall is reasonable. The onset is a little late and the rainfall is a little weak. Higher horizontal resolution and better physics may lead to improvements**

## PRECIPITATION (mm/day) JULY 2000-2004

**PRECIPITATION (mm/day) JULY 2000-2004**
**XIE-ARKIN CMAP**

**DIFF T126 - CMAP**

**DIFF T62 - CMAP**

## FREE COUPLED [CMIP] RUNS

**ATMOSPHERIC MODEL**
**1. T62L64                  CURRENT OPERATIONAL CFS **
**     ****49 years (2002-2050)**
**2. T126L64               CFS OPERATIONAL VERSION**
**     ****85 years (2002-2084)**
**3. T126L64                GFS OPERATIONAL VERSION**
**     ****30 years (2002-2031)**
**OCEAN MODEL**
**CFS OPERATIONAL MOM3 VERSION**

## T62 very regular ; T126 better variability, weaker amplitude

**T62 very regular ; T126 better variability, weaker amplitude**

## POSTER OF CÉCILE PENLAND : 

**MONDAY, 9-10:30 AM**
**EL NI****Ñ****O IN THE CLIMATE FORECAST SYSTEM : **
**T62 vs T126**
**Prepare CFS output as we do COADS data : project SSTs onto a  4° x 10° grid, subject to a 3-month running mean, and then project onto 20 leading EOFs**

## Conclusions: The resolution of the atmospheric component of the

**Conclusions: ****The resolution of the atmospheric component of the**
**                        ****model matters a lot! The T126 does get the El Niño**
**                        ****spectrum about right**

## Good variability ; Good amplitude

**Good variability ; Good amplitude**

## Good variability ; Good amplitude

**Good variability ; Good amplitude**

## Amplitude

**CDAS2**

**Amplitude**
**CHI 200 hPa**
**[10****7 ****m****2****/s]**
**T62 too strong**
**T126 better**

## Phase Speed

**Phase Speed**
**CHI 200 hPa [m/s]**
**Eastward speed**** : T62 too slow T126 better**
**Westward speed**** :**
**T62 too strong**
**T126 better**

**CDAS2**

**Westward propagating Easterly waves**

**MJO**

## Phase Speed

**CDAS2**

**Phase Speed**
**CHI 200 hPa [m/s]**
**At the Equator**
**Eastward speed**** : T62 too slow T126 better**
**Westward speed**** :**
**T62 too strong**
**T126 better**

**Semi-annual cycle in the observations not well simulated in any run**

## Illinois 2m column soil moisture from CMIP runs 

**Anomalies**

**Climatology**

**T126new has much reduced bias**

**Illinois 2m column soil moisture from CMIP runs **
**[ Courtesy: Fan and van den Dool, Thursday 10.30 AM ]**

## POSTER OF SUDHIR NADIGA : 

**MONDAY, 9-10:30 AM**
**ENSO-RELATED SALINITY VARIABILITY IN CFS**
**Salinity simulation from a free coupled run of the T62L64 operational CFS is compared to salinity estimates from GODAS as well as synthetic salinity dataset (Maes, 2000)**

## Conclusions: Salinity contributes significantly to the density variability in the global oceans. The sub surface salinity shows a strong ENSO-related signal in the western equatorial Pacific Ocean

**RED = WARM EVENTS**
**BLUE = COLD EVENTS**

- Different water masses, caused by zonal advection

**Conclusions: ****Salinity contributes significantly to the density variability in the global oceans. The sub surface salinity shows a strong ENSO-related signal in the western equatorial Pacific Ocean**

## LAYOUTSEASONAL MEANS AVERAGED OVER 24 YEARS[2007-2031]

-      CFS T126

- CFS T126 NEW

-        CFS T62

-                OBS

## PRATE [mm/day]         JJA

**PRATE [mm/day]         JJA**

## PRATE [mm/day]    BIAS     JJA

**PRATE [mm/day]    BIAS     JJA**

## PRATE [mm/day]         DJF

**PRATE [mm/day]         DJF**

## PRATE [mm/day]    BIAS     DJF

**PRATE [mm/day]    BIAS     DJF**

## PRATE [mm/day]    BIAS     JJA

**PRATE [mm/day]    BIAS     JJA**

## PRATE [mm/day]    BIAS     DJF

**PRATE [mm/day]    BIAS     DJF**

## PRATE [mm/day]    BIAS     JJA

**PRATE [mm/day]    BIAS     JJA**

## PRATE [mm/day]    BIAS     DJF

**PRATE [mm/day]    BIAS     DJF**

## PRATE [mm/day]    BIAS     JJA

**PRATE [mm/day]    BIAS     JJA**

## PRATE [mm/day]    BIAS     DJF

**PRATE [mm/day]    BIAS     DJF**

## CONCLUSIONS

**    ****A LOT MORE WORK NEEDS TO BE DONE TO IMPROVE THE CFS. ACTIVITIES ARE IN PROGRESS IN THE FOLLOWING AREAS :**
**INCREASED HORIZONTAL RESOLUTION OF THE ATMOSPHERIC MODEL**
**IMPROVED PHYSICS AND NUMERICS IN THE ATMOSPHERIC MODEL**
**NEW OCEAN MODEL WITH INCREASED HORIZONTAL AND VERTICAL RESOLUTION **
**NEW COUPLER**
**NEW LAND SURFACE MODEL**
**NEW ICE MODEL**
**ESMF COMPATIBLE**
**GLOBAL ATMOSPHERE-LAND-OCEAN COUPLED REANALYSIS**