# Presentation: 713279

## CTB Transition Project Team for Data Assimilation: Part 2: LAND

**Background:** At NCEP the _**Noah LSM**_ has been implemented in:
- Operational Global Forecast System (GFS) and its 4DDA (GDAS) _May05_
- Operational 25-year N. American Regional Reanalysis (NARR)
- Experimental Eta Regional Climate Model (Eta RCM)
- Experimental uncoupled Global Land Data Assimilation System (GLDAS)
- _NOT_ in operational _Climate Forecast System_ (uses ancestor OSU LSM)
**3 Land Experiments**
- _Add Noah LSM to CFS_: will CFS skill improve?
- Execute 360 members of CFS at T126
- 6 years x 2 seasons (winter/summer) x 15 members x 2 Experiments:
- Exp. A) Use Noah LSM,  Exp. B) Use OSU LSM (Control)
- Use Global Reanalysis 2 OSU-LSM based initial land states of ops CFS
- _Generate and apply superior initial land states for CFS-Noah_
- Execute 25-year “GLDAS”: uncoupled, land-only, continuous cycling of land states using Noah LSM and forced by observed precipitation analysis
- Repeat above 360 CFS members with GLDAS-Noah initial land states
- _Does Eta-Noah RCM seasonal-fcst skill surpass CFS over CONUS_
- 6 yrs x 2 seasons x10 members x 2 Exp (GR2 & NARR initial land states)
- Eta RCM driven by CFS seasonal forecasts of SST and lateral B.C.
- High-res RCMs may be necessary to achieve full potential of land impact

## 25-year GLDAS-Noah run completed: Example ResultsIllinois 2-meter Soil Moisture [mm]: 1985-2004 Average at 12 soil moisture measuring sitesPurple: GLDAS/Noah-LSM, Green: Global-Reanalysis-2/OSU-LSM, Black: Obs

**Total**

**Anomaly**

- Vtype 12

**Climatology**

- OSU LSM soil moisture climo has lower values than that of Noah LSM.  Taking
- Noah LSM initial states from OSU LSM states would yield low surface evaporation.

## JFM Precipitation anomaly for Winter 1983 ENSO Eta RCM vs ops CFS vs Observed(in terms of JFM precipitation accumulation in mm)

**Observed**

**ETA**

**CFS**

**CFS with no sea mask applied**

## Summary of Results to Date

- 25-year global GLDAS-Noah execution is completed and provides superior land states for CFS-Noah tests
- Land states that are self consistent with Noah LSM
- Initial land anomalies forced by observed precipitation
- Reveals Noah LSM soil moisture climatology meaningfully different (generally more moist) than that of OSU LSM of Global Reanalysis 2
- CFS-Noah LSM tests about to commence
- Start delayed by hiring & training of new team member
- CFS with Noah LSM built, with tools to insert desired initial land states
- Four experiment threads: CFS-Noah and CFS-OSU
- Each with paired runs: initial land states from 1) GR2-OSU, 2) GLDAS-Noah
- Eta RCM seasonal forecast tests completed
- Fully prognostic mode driven by CFS predicted SST and lateral B.C.
- Demonstrated the RCM testing protocol that CTB asks of external PIs
- Establish a mini RCM hindcast climatology on “neutral” yrs (2000-2004)
- Then test independent non-neutral years
- Examples: strong winter ENSO or strong U.S. summer monsoon
**1983 Winter ENSO event:  Eta RCM shows less skill than CFS**
**1999 Summer monsoon:   Eta RCM is modestly better than CFS**

## Future Efforts: this next year

- Commence CFS/Noah-LSM seasonal forecast tests
- GLDAS-Noah based source of initial land states now ready
- Time permitting, add tests initializing with land-state climo.
- Repeat Eta RCM forecast tests for several scenarios
- Bias correct the CFS SST forecasts before use in  Eta RCM
- Provide higher resolution SST forecasts
- Add CFS forecast of SST anomaly to high resolution SST climatology
- Use alternative initial land states:
- Via Regional Reanalysis (Noah LSM) rather than GR-2 (OSU LSM)
- Apply different convection scheme in Eta RCM
- Use different domain size for Eta RCM (smaller, quasi-CONUS)
- Test with SST and lateral boundary conditions from GR-2
- This is simulation mode rather than prognostic mode
- Study moisture flux convergence and surface fluxes
- compare that in CFS to Eta RCM, especially near coastline