Gene Feldman/NASA GSFC, Laboratory for Hydrospheric Processes, SeaWiFS Project Office Tasmanian scientists plan to use new satellite technology to provide early warnings about any large algal blooms which develop in Australian waters. CSIRO scientists have used the specialist instruments on two American satellites 800 kilometers (MODIS) above the earth's surface to pinpoint the largest algal bloom ever identified in Tasmanian waters. The bloom has been identified as non-toxic and stretches from Flinders Island, off the north-east coast, to the Tasman Peninsula near Hobart. Dr Ian Barton, from the CSIRO, says scientists hope to gain a better understanding of algal blooms in Australian waters by using the technology. "What we hope to do in the future is to in fact not only provide early warning that there is an algal bloom present in Australian waters but we want to be able to identify the species of that bloom," he said. Credit line for all images: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE Spring Bloom in the Tasman Sea 24 Oct 04

Validating global snow water equivalent and snow depth estimates from AMSR-E radio brightness observations Richard Kelly, Alfred Chang and James Foster NASA GSFC, Laboratory for Hydrospheric Processes, Hydrological Sciences Branch Space borne instruments have measured the interaction of natural upwelling microwaves from the Earth for over 30 years. The relationship between observed radio brightness temperature and snow water equivalent or SWE (the equivalent amount of liquid water in a column of snow) or snow depth is well understood both from a theoretical modeling standpoint and from a practical retrieval perspective (Chang et al., 1987). The intensity of microwave radiation emitted from a snow pack depends on several geophysical properties. SWE, grain size and local vegetation cover characteristics are dominant in their effect. Snow physical temperature, density and the underlying soil conditions are generally considered to be of secondary importance to the microwave emission. Recent studies have shown the utility of satellite passive microwave estimates of SWE and snow depth from dry seasonal snow packs with some success. Efforts are focused on error quantification and validation of SWE retrievals from the NASA/JAXA Advanced Microwave Scanning Radiometer – EOS (AMSR-E) snow algorithm. The analysis is conducted at the local pixel scale (25 km x 25 km) and at the regional river basin scale. NASA Cold Lands Processes Experiment data are useful for pixel scale analyses and have shown that for North Park in Colorado, grain size is the dominant control on SWE estimates (Figure 1). At the GEWEX Asian Monsoon Experiment (GAME) site in Yakutsk, Siberia, adjustments to the algorithm based on grain size estimates show that AMSR-E snow depth estimates are capable of successfully estimating snow depth through the season (Figure 2). At the regional scale, the algorithm can estimate successfully basin-wide snow depth. Figure 3 demonstrates the daily average snow depth in the Ob Basin, Siberia for the winter. AMSR-E estimates are compared with integrated ground measurements of snow depth from the World Meteorological Organization global surface summary of the day and show good agreement; the average daily basin-wide snow depth error for the winter was 5.4 cm. For local scale estimates in the regional domain, our work has shown (Figure 4) that to achieve better than 5 cm accuracy of snow depth representation by ground snow measurements, at least 9 distributed measurement sites are required (Chang et al., in press). This is important because there are very few places in the world where spatially dense networks of ground measurements exist.

Figure 1. The effect of grain size correction in the AMSR-E retrieval algorithm for North Park, CO, during the February 2003 CLPX field campaign. Improved grain size calibration is key to algorithm improvements. Figure 2. Application of a grain size correction to the AMSR-E retrieval algorithm for GAME Siberia experiment data ( ). Results show good agreement with the average snow depth from 7 field experiment sites. Land cover type (especially forest) also controls the microwave response from the snow. Tulagino Kenkeme Viluy Molot Larch Pine Khatassy Yakutsk, WMO/GTS. 0 km 50 Validating global snow water equivalent and snow depth estimates from AMSR-E radio brightness observations

Figure 3. Application of the standard AMSR-E retrieval algorithm to the Ob River basin in Siberia ( km 2 ) for winter season. Root mean squared error is 5.4 cm with a bias of –1.1 cm. Figure 4. Relationship between number of snow depth measurement sites and the associated random error within a 1° x 1° grid cell for the Northern Great Plains. To represent snow depth to within 5 cm of ‘truth’ at least 9 gauges per cell are required (Chang et al., In press) Validating global snow water equivalent and snow depth estimates from AMSR-E radio brightness observations

The first Cold Land Processes Field Experiment (CLPX-1) was conducted in Colorado in 2002 and 2003 to collect multi-scale remote sensing and ground truth to advance the understanding of process-level snow and frozen ground phenomena as well as to examine scaling behavior from the local scale to the satellite footprint scale. Studies are underway in Code 975 with passive microwave field data to evaluate forward radiative transfer modeling and retrieval algorithm skill for sites that included snowpacks in forested as well as unforested areas, and mountainous and non-mountainous terrain. Together, these are representative of ~80% of snowpacks found worldwide. Arctic snowpacks tend to be thinner, dryer, and can exhibit large-grain depth hoar formation due to the strong vertical temperature gradients during the cold winter conditions. One goal of a CLPX-2 would be a clearer understanding of Arctic snow characteristics and their corresponding microwave signatures in order to extend & enhance model and snow retrieval skill to a climatically & ecologically important type of region not examined in CLPX-1. Results could be extendable to similar areas across the entire Arctic. The Kuparuk River basin on the North Slope of Alaska has been the focus of unique cryo-hydrological studies for 20 years. It is relatively well-characterized in terms of soils, vegetation, & topography; it is relatively accessible & ground-instrumented, and so has been discussed as an excellent choice for a CLPX-2 site. Some microwave remote sensing experiments have even been conducted in the vicinity. In September, 2004, an aerial site inspection was conducted, to photographically document some of the typical landscape and land cover conditions that would be encountered. Aerial Site Inspection of Kuparuk, Alaska watershed for 2006 Cold Land Processes Field Experiment-2 Edward Kim/NASA GSFC, Laboratory for Hydrospheric Processes, Microwave Sensors Branch

Aerial Site Inspection of Kuparuk, Alaska watershed for 2006 Cold Land Processes Field Experiment-2 Edward Kim/NASA GSFC, Laboratory for Hydrospheric Processes, Microwave Sensors Branch A light snowfall highlights the hydrological importance of water tracks in the low-relief areas of the North Slope. Permafrost underlies the entire area, preventing infiltration. Tundra thaw ponds, a common landscape feature, form the backdrop for a highly localized snow squall. The site of a remote sensing study that examined passive microwave signatures on the North Slope. Trans-Alaska oil pipeline & haul road.