| Impacts | Loops | Real-time | Direct Broadcast | Data |
The MODerate-resolution Imaging Spectroradiometer (MODIS) and the Advanced Very High Resolution Radiometer (AVHRR) are being used to generate high-latitude wind fields by tracking cloud and water vapor features in infrared window and water vapor bands. The figures below shows MODIS band 31 (11 micron Infrared window) data for two 5-minute granules over part of Arctic and Antarctic. Cloud and water vapor targets were identified with an automated technique using three sets of images from consecutive overpasses about 1.5 hours apart. See the Loops page for higher density retrievals. See the Impacts page for some early results on how these winds affect numerical weather forecasts.
The main application of the MODIS and AVHRR polar winds are for numerical weather prediction (NWP). The following NWP centers are using the MODIS winds in their operational systems:
Real-time polar wind data are available with conditions. Data access and format is described here as a web page or here as a PDF file. If you're interested in the operational MODIS winds product, we recommend that you get them from NESDIS, as described in the document. Images of near real-time MODIS and AVHRR winds are available here.
AVHRR polar winds are only available in BUFR format via FTP at CIMSS. See the documentation page (link above) for information on contents and file name convention.
The direct broadcast MODIS polar winds are only available via FTP at CIMSS. They are available in BUFR and plain text formats. See the direct broadcast MODIS winds for more information about the direct broadcast sites.
How often can we obtain wind vectors from a polar-orbiting satellite? Not surprisingly, the answer depends on the latitude and the number of satellites. Click here to learn more.
This research is being performed by the following people: Jeff Key, Dave Santek, Chris Velden, and Dan Allman. Thanks to Fred Nagle for help on orbital characteristics. Model impact studies are being done at:
This research was supported by the NOAA and NASA.
Key, J., D. Santek, C.S. Velden, N. Bormann, J.-N. Thepaut, L.P. Riishojgaard, Y. Zhu, and W.P. Menzel, 2003, Cloud-drift and Water Vapor Winds in the Polar Regions from MODIS, IEEE Trans. Geosci. Remote Sensing, 41(2), 482-492. PDF version