Advanced Scatterometer Data Products

Described in this page are the data products derived from the Advanced Scatterometer (ASCAT) observations, which include:

The ASCAT ocean surface winds are a 10 meter neutral stability wind. These products are processed by NOAA/NESDIS utilizing measurements from ASCAT aboard the EUMETSAT METOP satellite. The current geophysical model function (GMF) being used is CMOD5.5, where the GMF relates the normalized radar cross-section to the ocean surface wind speed and direction.

The wind vector retrievals flagged as potentially being corrupt according to the KNMI quality flag are colored in black. For closer examination of the wind fields, a data image is further divided into 30x20 degree bins between latitudes 80N to 80S and longitudes 180W to 180E, forming a HTML link map for the regions of interest. Just click on the desired geographical location and a closer look should be provided.

In Europe, KNMI is responsible for the ASCAT wind products, and additional information can be found at the EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF).

The global wind images display the available data from the previous 22 hours up to the image creation time. Click here for the ocean surface winds from the near real-time (NRT) observation data.

For additional information about the EUMETSAT METOP or ASCAT programs, please visit the EUMETSAT Polar System (EPS).

ASCAT Storm Data

The storm centered imagery presented on this page are generated based on storm center files provided by NRL(Naval Research Laboratory at Monterey). These files are updated whenever new information about active storms become available, and the imagery is updated shortly after receipt of these files.

The ambiguity image plots all the ambiguities resulting from the wind retrieval process, with 4 being the maximum number of ambiguities. The NRCS, (Normalized Radar Cross-Section or Sigma0) link brings up a listing of recent NRCS images. The NRCS images shown here are gridded into an approximately 3 km grid in latitude and longitude. Currently only vertical polarization from the forward look is being shown. In the NRCS images, brighter means higher backscattered power levels, which in ocean scenes generally implies increased small scale (~2-5cm) roughness on the surface.

The hypothesis is that the NRCS images will prove useful in certain situations in locating features, such as storm centers, on the ocean surface. Especially in cases where the wind vector retrievals are inconclusive. There may be information in these images which will require experience in fully exploiting. Any feedback on these images would be appreciated.

Details about these and other enhanced resolution scatterometer image products can be found at the: NASA Scatterometer Climate Record Pathfinder Project Homepage

Comments and suggestions are welcome.

ASCAT Ice Data

The daily ice image products are generated from the ASCAT Level 1B sigma0 data which are operationally obtained from EUMETSAT. The images are produced using software that was developed as part of the NASA Scatterometer Climate Record Pathfinder Project. The data product contains the most recent images covering the Antarctic, the Arctic, the Ross Ice Shelf, South Georgia Island and the Weddell Sea. The Antarctic and Arctic products typically span a 24-hour data period, while the other regions span a 38-hour period.

The coverage may vary due to delays in data availability or rev reprocessing. Current products include the v-pol average, the v-pol SIR(Scatterometer Image Reconstruction) and the ocean-masked image.

Details about these and other scatterometer image products can be found at the: NASA Scatterometer Climate Record Pathfinder Project Homepage.