The document discusses the NASA Soil Moisture Active Passive (SMAP) mission, which is scheduled for launch in 2014. SMAP will map global soil moisture and freeze/thaw state from space to further understanding of the water, energy, and carbon cycles. The mission involves an L-band radar and radiometer to provide soil moisture measurements. Algorithms are being developed and tested to generate products like soil moisture maps from the radar-radiometer data. Validation efforts and working groups are helping prepare for the mission.

1. NASA Soil Moisture Active Passive (SMAP) Mission Formulation Dara Entekhabi (MIT) Eni Njoku (JPL Caltech/NASA) Peggy O'Neill (GSFC/NASA) Kent Kellogg (JPL Caltech/NASA) Jared Entin (NASA HQ) IGARSS’11 Session WE1.T03.1 Paper #3178

4. May 10 Dry soil, clear, mild winds. (LE≈H) May 18 90 mm Rain May 20 Moist soil, clear, mild winds. (LE>H) Pathways of Soil Moisture Influence on Weather and Climate CASES’97 Field Experiment, BAMS , 81(4), 2000. Dry Soil Moist Soil 5°C Dry Surface Moist Surface Deep Mixing up to 1.5 km Altitude Shallow Mixing to 1.0 km

5. Source: Cahill et al., J. Appl. Met ., 38 Key Determinants of Land Evaporation Latent heat flux (evaporation) links the water , energy , and carbon cycles at the surface. Closure relationship, yet virtually unknown. Lack of knowledge of soil moisture control on surface fluxes causes uncertainty in weather and climate models.

6. NOAH CLM What Do We Do Today? Dirmeyer et al., J. Hydromet., 7, 1177-1198, 2006 Atmospheric model representations of this function are essentially “guesses”, given scarcity of soil moisture and evaporation data.

7. (*) % classification accuracy (binary Freeze/Thaw) (**) [cm 3 cm -3 ] volumetric water content, 1-sigma Science Requirements (1) North of 45N latitude Requirement Hydro-Meteorology Hydro-Climatology Carbon Cycle Baseline Mission Soil Moisture Freeze/Thaw Resolution 4–15 km 50–100 km 1–10 km 10 km 3 km Refresh Rate 2–3 days 3–4 days 2–3 days (1) 3 days 2 days (1) Accuracy 4–6% ** 4–6%** 80–70%* 4%** 80%* DS Objective Application Science Requirement Weather Forecast Initialization of Numerical Weather Prediction (NWP) Hydrometeorology Climate Prediction Boundary and Initial Conditions for Seasonal Climate Prediction Models Hydroclimatology Testing Land Surface Models in General Circulation Models Drought and Agriculture Monitoring Seasonal Precipitation Prediction Hydroclimatology Regional Drought Monitoring Crop Outlook Flood Forecast Improvements River Forecast Model Initialization Hydrometeorology Flash Flood Guidance (FFG) NWP Initialization for Precipitation Forecast Human Health Seasonal Heat Stress Outlook Hydroclimatology Near-Term Air Temperature and Heat Stress Forecast Hydrometeorology Disease Vector Seasonal Outlook Hydroclimatology Disease Vector Near-Term Forecast (NWP) Hydrometeorology Boreal Carbon Freeze/Thaw Date Freeze/Thaw State

8. Sources: Global Forecast/Analysis System Bulletins http://www.emc.ncep.noaa.gov/gmb/STATS/html/model_changes.html The ECMWF Forecasting System Since 1979 http://ecmwf.int/products/forecasts/guide/The_general_circulation_model.html Trends in Short-Term Weather (0-14 Days) NWP Resolution Hydrometeorology Applications: NWP SMAP

9. Operational Flood and Drought Applications Current : Empirical Soil Moisture Indices Based on Rainfall and Air Temperature ( By Counties >40 km and Climate Divisions >55 km ) Future : SMAP Soil Moisture Direct Observations of Soil Moisture at 10 km

11. Data Products SMAP is Taking Aggressive Hardware & Softwate Measures to Detect & Partially Mitigate RFI Product Description Resolution Latency L1A_TB Radiometer Data in Time-Order - 12 hrs Instrument Data L1A_S0 Radar Data in Time-Order - 12 hrs L1B_TB Radiometer T B in Time-Order 36x47 km 12 hrs L1B_S0_LoRes Low Resolution Radar σ o in Time-Order 5x30 km 12 hrs L1C_S0_HiRes High Resolution Radar σ o in Half-Orbits 1-3 km 12 hrs L1C_TB Radiometer T B in Half-Orbits 36 km 12 hrs L2_SM_A Soil Moisture (Radar) 3 km 24 hrs Science Data (Half-Orbit) L2_SM_P Soil Moisture (Radiometer) 36 km 24 hrs L2_SM_A/P Soil Moisture (Radar+Radiometer) 9 km 24 hrs L3_F/T_A Freeze/Thaw State 3 km 50 hrs Science Data (Daily Composite) L3_SM_A Soil Moisture (Radar) 3 km 50 hrs L3_SM_P Soil Moisture (Radiometer) 36 km 50 hrs L3_SM_A/P Soil Moisture (Radar+Radiometer) 9 km 50 hrs L4_SM Soil Moisture (Surface and Root Zone ) 9 km 7 days Science Value-Added L4_C Carbon Net Ecosystem Exchange (NEE) 9 km 14 days

13. L2_SM_AP Radar-Radiometer Algorithm Heterogeneity in Vegetation and Roughness Conditions Estimated by Sensitivities Γ in Radar HV Cross-Pol: T B ( M j ) is Used to Retrieve Soil Moisture at 9 km T B -Disaggregation Algorithm is: National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California Temporal Changes in T B and σ pp are Related. Relationship Parameter β is Estimated at Radiometer-Scale Using Successive Overpasses. Based on PALS Observations From: SGP99, SMEX02, CLASIC and SMAPVEX08

14. SGP99, SMEX02, CLASIC and SMAPVEX08 WE2.T03.2 Paper #: 3398 Title: Evaluation of the SMAPCombined Radar-Radiometer Soil Moisture Algorithm Authors: N. Das, D. Entekhabi, S. Chan, S. Kim, E. Njoku, R. Dunbar, J.C. Shi Active-Passive Algorithm Performance Minimum Performance Algorithm RMSE: 0.055 [cm 3 cm -3 ] Active-Passive Algorithm RMSE: 0.033 [cm 3 cm -3 ]

16. SMAP Algorithm Testbed TB (K) L2_SM_AP Combined Soil Moisture Product (9 km) L2_SM_P Radiometer Soil Moisture Product (36 km) L3_SM_A Radar Soil Moisture Product (3 km) L1C_TB Radiometer Brightness Temperature Product (36km) Simulated products generated with prototype algorithms on the SDS Testbed National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California WE2.T03.1 Paper #2069 Title: Utilization of ancillary data sets for SMAP Algorithm Development and Product Generation Authors: P. O'Neill, E. Podest, E. Njoku L1C_S0_Hi-Res Radar Backscatter Product (1-3 km)

18. Back-Up Slides