NOAA’s Climate Prediction Center & *Environmental Modeling Center Camp Springs, MD 20746

1. Impact of High-Frequency Variability of Soil Moisture on Seasonal Precipitation Song Yang, S.-H. Yoo R. Yang*, K. Mitchell*, H. van den Dool, and R. W. Higgins NOAA’s Climate Prediction Center & *Environmental Modeling Center Camp Springs, MD 20746 Table of Contents Motivation Model and experiments Results, explanations, & summary Future work

2. Motivation Yang and Lau (1998; J. Climate)

3. 2. Model and experiments 2. Model and experiments 2. Model and experiments Model resolution: 32-km in horizontal; 45 levels in vertical Model domain: 10N-90N, 164W-58W Noah Land Model 2.3, with 4 soil layers Implemented in Operational NCEP Eta Model Implemented in NCEP Regional Reanalysis Boundary conditions: NCEP/NCAR Global Reanalysis II Initial conditions: NCEP/NCAR Global Reanalysis II U.S. Air Force daily analysis of snow depth Initial land states data: NCEP/NCAR Global Reanalysis II (in experiment Eta (GRII)) NCEP Regional Reanalysis (in experiment Eta (R/R)) Starting months: December in Eta (GRII) April in Eta (R/R) Length of integrations: 9 months in Eta (GRII) 4 months in Eta (R/R) # of ensemble members: 5 Sea surface temperature, surface albedo, and greenness: Updated daily Data of verifications: NCEP Regional Reanalysis NCEP Land Data Assimilation System NOAA’s Climate Prediction Center Unified Precipitation Global Telecommunications Model resolution: 32-km in horizontal; 45 levels in vertical Model domain: 10N-90N, 164W-58W Noah Land Model 2.3, with 4 soil layers Implemented in Operational NCEP Eta Model Implemented in NCEP Regional Reanalysis Boundary conditions: NCEP/NCAR Global Reanalysis II Initial conditions: NCEP/NCAR Global Reanalysis II U.S. Air Force daily analysis of snow depth Initial land states data: NCEP/NCAR Global Reanalysis II (in experiment Eta (GRII)) NCEP Regional Reanalysis (in experiment Eta (R/R)) Starting months: December in Eta (GRII) April in Eta (R/R) Length of integrations: 9 months in Eta (GRII) 4 months in Eta (R/R) # of ensemble members: 5 Sea surface temperature, surface albedo, and greenness: Updated daily Data of verifications: NCEP Regional Reanalysis NCEP Land Data Assimilation System NOAA’s Climate Prediction Center Unified Precipitation Global Telecommunications Model resolution: 32-km in horizontal; 45 levels in vertical Model domain: 10N-90N, 164W-58W Noah Land Model 2.3, with 4 soil layers Implemented in Operational NCEP Eta Model Implemented in NCEP Regional Reanalysis Boundary conditions: NCEP/NCAR Global Reanalysis II Initial conditions: NCEP/NCAR Global Reanalysis II U.S. Air Force daily analysis of snow depth Initial land states data: NCEP/NCAR Global Reanalysis II (in experiment Eta (GRII)) NCEP Regional Reanalysis (in experiment Eta (R/R)) Starting months: December in Eta (GRII) April in Eta (R/R) Length of integrations: 9 months in Eta (GRII) 4 months in Eta (R/R) # of ensemble members: 5 Sea surface temperature, surface albedo, and greenness: Updated daily Data of verifications: NCEP Regional Reanalysis NCEP Land Data Assimilation System NOAA’s Climate Prediction Center Unified Precipitation Global Telecommunications Model NCEP Eta Regional Climate Model Resolution: 32-km in horizontal; 45 levels in vertical Domain: 10N-90N, 164W-58W Noah Land Model 2.3, with 4 soil layers Implemented in Operational NCEP Eta Model Implemented in NCEP Regional Reanalysis Boundary conditions: NCEP/NCAR Global Reanalysis Initial conditions: NCEP/NCAR Global Reanalysis U.S. Air Force daily analysis of snow depth Initial land states: NCEP Regional Reanalysis

4. 2. Model and experiments 2. Model and experiments 2. Model and experiments Model resolution: 32-km in horizontal; 45 levels in vertical Model domain: 10N-90N, 164W-58W Noah Land Model 2.3, with 4 soil layers Implemented in Operational NCEP Eta Model Implemented in NCEP Regional Reanalysis Boundary conditions: NCEP/NCAR Global Reanalysis II Initial conditions: NCEP/NCAR Global Reanalysis II U.S. Air Force daily analysis of snow depth Initial land states data: NCEP/NCAR Global Reanalysis II (in experiment Eta (GRII)) NCEP Regional Reanalysis (in experiment Eta (R/R)) Starting months: December in Eta (GRII) April in Eta (R/R) Length of integrations: 9 months in Eta (GRII) 4 months in Eta (R/R) # of ensemble members: 5 Sea surface temperature, surface albedo, and greenness: Updated daily Data of verifications: NCEP Regional Reanalysis NCEP Land Data Assimilation System NOAA’s Climate Prediction Center Unified Precipitation Global Telecommunications Model resolution: 32-km in horizontal; 45 levels in vertical Model domain: 10N-90N, 164W-58W Noah Land Model 2.3, with 4 soil layers Implemented in Operational NCEP Eta Model Implemented in NCEP Regional Reanalysis Boundary conditions: NCEP/NCAR Global Reanalysis II Initial conditions: NCEP/NCAR Global Reanalysis II U.S. Air Force daily analysis of snow depth Initial land states data: NCEP/NCAR Global Reanalysis II (in experiment Eta (GRII)) NCEP Regional Reanalysis (in experiment Eta (R/R)) Starting months: December in Eta (GRII) April in Eta (R/R) Length of integrations: 9 months in Eta (GRII) 4 months in Eta (R/R) # of ensemble members: 5 Sea surface temperature, surface albedo, and greenness: Updated daily Data of verifications: NCEP Regional Reanalysis NCEP Land Data Assimilation System NOAA’s Climate Prediction Center Unified Precipitation Global Telecommunications Model resolution: 32-km in horizontal; 45 levels in vertical Model domain: 10N-90N, 164W-58W Noah Land Model 2.3, with 4 soil layers Implemented in Operational NCEP Eta Model Implemented in NCEP Regional Reanalysis Boundary conditions: NCEP/NCAR Global Reanalysis II Initial conditions: NCEP/NCAR Global Reanalysis II U.S. Air Force daily analysis of snow depth Initial land states data: NCEP/NCAR Global Reanalysis II (in experiment Eta (GRII)) NCEP Regional Reanalysis (in experiment Eta (R/R)) Starting months: December in Eta (GRII) April in Eta (R/R) Length of integrations: 9 months in Eta (GRII) 4 months in Eta (R/R) # of ensemble members: 5 Sea surface temperature, surface albedo, and greenness: Updated daily Data of verifications: NCEP Regional Reanalysis NCEP Land Data Assimilation System NOAA’s Climate Prediction Center Unified Precipitation Global Telecommunications Experiments Period: May-August of 1988 and 1993 Starting months: April Length of integrations: 4 months Number of ensemble members: 5 SST, surface albedo, and greenness: Updated daily Data of verifications: NCEP Regional Reanalysis; NCEP Land Data AssimilationSystem; CPC Unified Precipitation; and Global Telecommunications Soil moisture as surface boundary forcing in sensitivity experiments: 3-hourly means Daily means Weekly means

5. Results I: Control Runs Model-observation comparison

6. Precipitation (1993-1988) Eta RR CPC

7. Surface Temperature (1993-1988) Eta RR GTS

9. Soil Moisture (1993-1988) LDAS data from Dr. Yun Fan

10. Results II: Sensitivity Experiments Roles of diurnal cycle & sub-synoptic variability of soil moisture Soil moisture as surface boundary forcing: 3-hourly means Daily means Weekly means

11. Ts JJA 1988 Precip 3 Hourly 3H-Daily 3H-Weekly

12. T850 Ts 3 Hourly 3H-Daily 3H-Weekly JJA 1988

13. 3 Hourly 850-mb Winds JJA 1988 3H-Daily 3H-Weekly

14. Precip of JJA 1993 Precip of JJA 1988 3 Hourly 3H-Daily 3H-Weekly 3H-Weekly

15. Ts of JJA 1988 Ts of JJA 1993 3 Hourly 3H-Daily 3H-Weekly

16. T850 of JJA 1988 T850 of JJA 1993 3 Hourly 3H-Daily 3H-Weekly

17. 3 Hourly JJA 1988 JJA 1993 3H-Daily 3H-Weekly

18. Explanations

22. Summary • Reasonable performance by Eta • Impact of sub-synoptic soil moisture variability • HF var. of soil moisture changes seasonal means of precip. • Different roles between 1988 and 1993 • Importance of diurnal cycle • Dynamical consistence • Explanation (water and heat fluxes, instability, etc.)

23. Future Work Impact of the spatial structure of soil moisture