CFS Test and Evaluation Team Team Mission

1. CFS Test and Evaluation Team • Team Mission • Perform sensitivity experiments and evaluate the results. Experiments are designed to accelerate the development of CFS. Team Membership: EMC and CPC federal and contract employees, and CTB funded investigators. Two types of experiments are performed on the CTB computer i. CTB funded projects ii. Internal projects proposed by CTB T & E Team members, reviewed and approved by CST Balance will shift from ii) to i) as CTB grants increase.

2. FY07 accomplishments - 17 experiments proposed and approved by CST. - Most experiments finished and preliminary evaluation done. - CTB T&E Team has fostered successful collaboration between EMC and CPC. - This should evolve further in FY08 as the competitive grants program grows and additional PIs join CTB. FY07 experiments have provided some insight and recommendations towards the next CFS.

3. Selected results from experiments and evaluations

4. CFS subseasonal hindcast run (Vintzileos and Pan ) 60-day forecast runs in 5-day intervals during May-August, 2002-2006. 2. Impact of horizontal resolution (T62, T126, T254) and initial condition (GDAS, CDAS2) examined. Principal findings and recommendations 1. New CFS needs to be accompanied by its own reanalysis. 2. Impact of model resolution detected in tropical Atlantic and Africa - downscaling of operational forecasts could be beneficial in those sectors.

5. √2 x Climatological Forecast (i.e., anomaly=0) CDAS initialized T62 hindcasts are the worst GDAS initialized T254 hindcasts are the best Because we validate against CDAS (starting from 06Z) Lead times from 0 to 25 days

6. Test of RRTM shortwave radiation code (Hou and Saha) • AER RRTM-SW radiation scheme has been incorporated into the new GFS/CFS. Also included are other physical processes such as solar-cycle, aerosol effect (including historical volcanic origin) and historical CO2. • T126/MOM3 version was run from 01/01/1948 for 60 years. • Comparison of global mean SST, T2m anomalies, and global map of SST climatology shows promising improvement over the control model. - Served as a benchmark for other GFS evaluations.

7. RRTM run shows reduced SST warm bias

8. CFS with Noah LSM and GLDAS(Mitchell, Yang and Meng)Impact on CFS of: A) new land model (Noah LSM vs OSU LSM)B) new land initial conditions (GLDAS vs GR2) • 25-year 10-member 6-month T126 CFS runs • Four configurations of T126 CFS: • A) CFS/OSU/GR2: - OSU LSM, ICs from GR2 (CONTROL) • B) CFS/Noah/GR2: - Noah LSM, ICs from GR2 • C) CFS/Noah/GLDAS: - Noah LSM, land ICs from T126GLDAS/Noah • D) CFS/Noah/GLDAS-Climo: - Noah LSM, land ICs from GLDAS/Noah climo • 25 summers: (1980-2004) Initial conditions: 00Z daily from Apr 19-23 29,30, and May 1-3 • 10 winters: (83, 88, 89, 90, 98, 00, 01, 02, 03, 04) • Initial conditions: 00Z daily from Nov 29-30, Dec 1-3, Dec 19-23 • For summers 1999 & 2000 only for ensemble size and lead time test • Evaluations focused on impact of land state initialization on precipitation and surface air temperature over North America, and global SST - GLDAS land initial condition necessary for Noah LSM • Implication - New CFS reanalysis crucial for new CFS

9. JJA Precip Correlation Skills w Different LSM/ICs over NA Noah/GLDAS Noah/GR2 Noah/GLDAS CLM OSU/GR2

10. JJA Mean T2m Correlation Skill Comparison Ops CFS T62 April ICs Noah/ GLDAS OSU/ GR2 Ops CFS Noah/ GLDAS Climo

11. JJA Mean SST Correlation Skill w Different LSM/ICs Globally Noah/ GR2 Noah/ GLDAS Noah/ GLDAS Climo OSU/ GR2 10 Members each case (same initial dates)

12. Rerun of the offline Noah Land Model for 1948-2006 • (Fan and van den Dool) • Improvements in the model, vegetation class table and input precipitation datasets. • Homogeneous input for both retrospective (from 1948) and real-time analysis. Main findings • Soil moisture anomalies and annual cycles are improved in top two layers, • but the dry end of annual cycles are about 1~2 month late. • Anomalies in lower layers are comparable with old run, however, • the amplitudes of annual cycles much larger than Obs as in older version. • Slight changes in evaporation and runoff are found in northern US. • About 10~20 mm/mon increase (decrease) in evaporation (runoff) • is seen in southeastern US.

13. NLDAS Re-run

14. T382 CFS runs for hurricane season (Saha, Thiaw) • AGCM - 2007 operational NCEP GFS • LSM - Noah LSM • OGCM - GFDL MOM3 • All runs initialized with NCEP/DOE R2 and NCEP GODAS at 0Z, May 15, 1981-2006. • AGCM spatial resolution in T382L64. Companion runs made in T126L64 and T62L64 also. • This experiment has been extensively analyzed by the Evaluation Team members(L. Long, H. Wang, Schemm, W. Wang)

15. Atlantic Eastern North Pacific Western North Pacific North Indian Examples of Storm Tracks for 4 NH Basins

16. Atlantic Basin Correlations Total: r=0.38 ’81-’93: r=0.15 ’94-’06: r=0.37

17. Eastern Pacific Basin Correlations Total: r=0.16 ’81-’93: r=0.04 ’94-’06: r=0.02

18. T62 T126 T382 OBS New CFS Runs 3 different resolutions ICs: May 15 (1 member) SST SSTA in MDR ASO 2 month lead Correlation (CFS, OBS) Linear trend removed Co .75 .69 .74 .66 .54 .65 T62 T126T382 T62 T126T382 Year Warming trend contributes to the high correlation.

19. T62 T126 T382 OBS New CFS Runs 3 different resolutions ICs: May 15 (1 member) U200–U850 U200–U850 in MDR ASO 2 month lead Correlation (CFS, OBS) Linear trend removed m/s .62 .57 .48 .58 .34 .42 T62 T126T382 T62 T126T382 Year Lower resolution better wind shear (single run)

20. Summary • CFS in T382 resolution exhibits fairly robust climatological seasonal cycle of tropical cyclone over four NH basins. • Warming trend and intensification of hurricane activity in the Atlantic basin captured. • Increased horizontal resolution may lead to improved vertical wind shear prediction over the Atlantic MDR. • Ensemble members needed for better depiction of large scale circulation. • Coupled air-sea interaction: important

21. CFS E. Pacific SST bias corrections (Xie, Wang) • Impact of radiation flux error over the Southeastern Pacific examined. SST bias reduced by half from surface radiation • bias correction.

22. Impacts of radiation flux errors over the Southeastern Pacific (SEP) Annual mean precipitation • Correction of SEP radiation errors improves double ITCZ in coupled and uncoupled runs Coupled with SEP radiation errors Coupled without SEP radiation errors AMIP with SST errors associated with radiation errors AMIP without SST errors

23. CFS hindcast rerun with corrected GODAS (W. Wang, Xue, Schemm) • Reruns with June and December initial conditions - Evaluations on SST and atmospheric variables performed. • Mean SST is reduced by 0.2-0.4 degree due to GODAS corrections - reduces warm biases but worsens cold biases, particularly for June IC’s. • Changes in precipitation bias are confined in the Tropics. SST hindcast skill is improved, most prominent in the Pacific and Indian Ocean for December IC’s and in the Atlantic Ocean for June IC’s. • No significant changes in skill over North America for 2m temperature and precipitation. • Provided analysis with April IC’s for hurricane seasonal outlook issued in May 2007.

24. SST Indices Hindcast Skill in 1981-2005 (red  improvement) JAS OND JFM

25. SST hindcast averaged in the hurricane main development region (MDR) for July-November starting from June 11-31 I.C.. The SST hindcast is reduced (green) in 1981-1990 and increased (red) in 1991-2005 due to GODAS corrections. CFS realistically simulated the peaks of the index in 1987, 1995, 1998 and 2003-2005, and valleys in 1984-1986 and 1994, which suggests a potential contribution of the CFS forecast for the hurricane outlook.

26. North America

27. Summary CTB T&E Team has fostered successful collaboration between EMC and CPC. This successful collaboration should evolve further in FY08 with funded projects for the next+1 CFS. FY07 experiments provided some insight and recommendations towards the next CFS.

28. For FY08 - Main focus : To participate in CFS reanalyasis and reforecasts - To experiment with and evaluate the impact of suggested changes to CFS by funded external proposals.