Intercalibration of near-real-time snow and sea ice products from passive microwave Data

Global estimates of snow and sea ice from passive microwave imagery are among the longest satellite-derived climate records in existence. The speed of observed changes in the cryosphere is pushing demand for near-real-time information that can provide at least preliminary estimates of evolving conditions. Such data are also valuable in the production of other geophysical products and as input to climate and weather models. Issues may arise in dealing with near-real-time satellite data that necessitate adaptive and quick intercalibration, and adjustments to production algorithms. Here we discuss issues that have affected production at the National Snow and Ice Data Center (NSIDC) of near-real time snow and sea ice products derived from DMSP passive microwave sensors. These issues include: sudden loss of data due to malfunctioning satellite data recorders, corruption of the signal on some channels, calibration errors in the source data, transitioning to a new sensor (from SSM/I to SSMIS), and dealing with changes in data providers and data format. The lessons learned from our experiences should prove beneficial as more real-time and near-real-time data streams become available and the demand for these products, and rapid response science, increases.