1. Recent SeaWiFS view of the forest fires over Alaska Gene Feldman, NASA GSFC, Laboratory for Hydrospheric Processes, Office for Global Carbon Studies (gene.c.feldman@nasa.gov) A more detailed view can be seen at: http://seawifs.gsfc.nasa.gov/SEAWIFS/IMAGES/NEW/Alaska/S2004179232723.L1A_HUAF.AlaskaSmoke.png

2. Smoke over Alaska from Forest Fires

3. Comparison of Soil Moisture Retrieval Algorithms Using Simulated HYDROS Brightness Temperatures HYDROS mission objective is to collect global scale measurements of the Earth’s soil moisture and land surface freeze/thaw conditions, using a combined L band radiometer and radar system operating at 1.41 and 1.26 GHz An observing system simulation experiment (OSSE) was conducted in order to test HYDROS soil moisture retrieval algorithms and examine how the retrieval accuracy will be impacted by vegetation water content and surface heterogeneity -- modeled geophysical domain in the south-central United States centered on the Arkansas- Red River basin for a one-month period in 1994 Three separate radiometer retrieval algorithms were evaluated: -- (1) a single-channel algorithm (H polarization), (2) a two-channel iterative algorithm, and (3) a two-channel reflectivity ratio algorithm Results indicate that the HYDROS accuracy goal of 4% volumetric soil moisture can be met anywhere in the test basin except woodland areas on the east side of the basin Nonlinear scaling of higher resolution ancillary vegetation data can adversely affect algorithm retrieval accuracies, especially in heavy tree areas on the east side of the basin. Methods for “effectively” aggregating high resolution vegetation data to improve soil moisture retrieval algorithms for satellite microwave missions are currently under study. P. O’Neill*, W. Crow, A. Hsu, E. Njoku, T. Chan, and JC Shi *NASA GSFC, Laboratory for Hydrospheric Processes, Hydrological Sciences Branch (peggy.oneill@nasa.gov)

4. HYDRS Mixed Forest/ Grassland Grassland/ Crops Shrubland/ Semi-arid Forest Water Land Cover Classification 36 km 9 km Land Cover Heterogeneity (1-km pixels) OSSE Domain Characteristics Topography 575,000 km 2 basin OSSE one-month test period from May 26 – June 28, 1994

5. OSSE Approach:  land surface model is used to generate geo- physical parameters for test basin at 1 km scale (includes representative dynamic ranges of soil moisture, temperature, land cover, VWC, & other surface characteristics)  T B and σ values are computed using forward microwave model at HYDROS frequencies, polarizations, and incidence angle (40  )  expected instrument is noise added  T B and σ results are aggregated to HYDROS radiometer (40 km) and radar (3 km) instrument resolutions  soil moisture retrieval algorithms are applied to these simulated HYDROS data (only radiometer results reported here)  OSSE is repeated for special cases of doubling and tripling vegetation HYDROS OSSE Approach and Basin Average Results Comparison of soil moisture retrieval accuracy for three candidate HYDROS algorithms at the basin average scale, showing that all three algorithms meet the HYDROS target accuracy of 4% vol. soil moisture.

6. HYDROS Vegetation Aggregation Effects on SM Retrieval Accuracy (a) (b) (c) (a) any 36-km pixels with large error occur in the eastern 20% of the basin where 80% of the land cover is in trees/crop/mixed woodland (b) the single channel algorithm is adversely affected by aggregation of 1 km ancillary VWC data to 36 km (to match HYDROS T B scale) (c) most of these errors are eliminated if SM is retrieved at 1 km, then aggregated to 36 km, further confirming problem of nonlinear scaling of high resolution ancillary vegetation data to satellite footprint resolutions

7. Using satellite-derived ice concentrations to represent Antarctic coastal polynyas in ocean climate models Thorsten Markus, NASA GSFC, Laboratory for Hydrospheric Processes, Microwave Sensors Branch Achim Stoessel, Texas A&M University, College Station, TX Coastal polynyas are areas of open water surrounded by sea ice along the Arctic and Antarctic coasts which are formed by wind-driven offshore ice advection. Because in these areas the relatively warm ocean is in direct contact with the cold polar atmosphere, they are sites of intense freezing and thus brine release, and therefore have a strong impact on water mass transformation which affects the global ocean circulation. Coastal polynyas and related processes are difficult reproduce in models because of their small extent so that they are often below the resolution of models their complex dynamics large uncertainties in wind vectors along the coasts. Ingestion (assimilation) of satellite-derived (passive microwave) ice concentrations circumvents the problem of modeling these coastal polynyas and improves the associated fresh-water fluxes. Reference: A. Stoessel and T. Markus, JGR-Oceans, 10.1029/2003JC001779, 2004.

8. Difference in model annual net freezing rate (assimilated minus non-assimilated). Contour interval: 1 m Using satellite-derived ice concentrations to represent Antarctic coastal polynyas in ocean climate models