The Scatterometer Climate Record Pathfinder Project

The NASA Scatterometer Climate Record Pathfinder (SCP) is a NASA-sponsored collaborative project between investigators at Brigham Young University (BYU), the Jet Propulsion Laboratory (JPL), the European Space Agency (ESA), and the National Ice Center (NIC) to develop accurately calibrated scatterometer-based data time series in support of climate-related studies of the Earth's cryosphere and biosphere. Originally developed to measure winds over the ocean from space, microwave radar scatterometers have proven to be applicable over a wide range of vegetation zones and moisture conditions including wet, dry and frozen. Because the scatterometer radar signal can penetrate the surface, a scatterometer can observe variability in subsurface/subcanopy climate-related features which are driven by diurnal, seasonal, and interannual forcing.

The launch of Seasat, carrying a Ku-band scatterometer (SASS), in 1978 provided a baseline against which studies of global change can be measured. Other missions have followed SASS, including the C-band European Space Agency (ESA) Earth Remote Sensing (ERS) -1 and -2 missions (1992+), the NASA Scatterometer (NSCAT) mission aboard the Japanese ADEOS satellite in 1996-97, SeaWinds on QuikSCAT (1999+), and SeaWinds on ADEOS-II (2003). With their rapid global coverage, day or night and all-weather operation, scatterometers offer a unique tool for long-term climate studies. The goal of the SCP is to provide scatterometer-based datasets to researchers involved in climate studies.

The SCP datasets are based primarily on a time series of enhanced resolution images made from the scatterometer backscatter (sigma0) measurements using the Scatterometer Image Reconstruction (SIR) and SIR w/filtering (SIRF) algorithms. For the highest possible spatial resolution (as well as to ensure full coverage over the images) multiple orbit passes are combined. There is thus a tradeoff between temporal and spatial resolution. For SASS, NSCAT, and ERS, images of sigma0 at 40 deg incidence angle (A) in dB and the slope of sigma0 versus incidence angle (B) in dB/deg are made. For QuikSCAT and SeaWinds sigma0 images at the observation incidence angles are made. In addition to these images, a number of ancillary images and derived products are generated including sea ice extent maps and sea ice motion data sets. From the time series of radar backscatter images and derived products, key climate-related parameters can be extracted for use in global climate change studies.

The principal repository for these datasets is the SCP URL https://www.scp.byu.edu/ where files are publicly available using a browser or ftp. The Physical Oceanography Distributed Active Archive Center (PO.DAAC) will mirror, archive, and also distribute the data via select media. Currently, CDs of the QuikSCAT Sigma-0 Browse Product can be ordered from the PO.DAAC at URL https://podaac.jpl.nasa.gov/quikscat/qscat_data.html Other SCP datasets will also be available from the PO.DAAC at URL https://podaac.jpl.nasa.gov/.

Selected ice products are archived at, and available from, the National Snow and Ice Data Center (NSIDC)