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Blended Sea Winds

SummaryData AccessFrequently Asked QuestionsBibliographyContact
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The Blended Sea Winds contain globally gridded, high resolution ocean surface vector winds and wind stresses on a global 0.25° grid, and multiple time resolutions of 6-hourly, daily, monthly, and 11-year (1995-2005) climatological monthlies. The period of record is 9 July 1987 - present. The wind speeds were generated by blending observations from multiple satellites (up to six satellites since June 2002; Figure 2). The wind directions came from two sources depending on the products: for the research products the source is the NCEP Reanalysis 2 (NRA-2) and for near-real-time products the source is the ECMWF NWP. The wind directions were interpolated onto the blended speed grids.

global sea winds animation
Figure 1 - Click on image to see latest animation (3mb)
Please read disclaimer for the near-real-time products

The blending of multiple-satellite observations fill in the data gaps (in both time and space) of the individual satellite samplings and reduce the subsampling aliases and random errors. The development of these products is in response to the demand for increasingly higher resolution global datasets. For example, scientists want to make more accurate forecasts of ocean and weather conditions. Links to articles on the high resolution feasibility study and the blending methodology are found in the Bibliography section below.

satellites' operational periods
Figure 2 - Equator crossing times. Red ascending and black descending.
click on image for larger view

Figure 3 shows the evolution of the averaged data sampling time interval by the long-term multiple satellites that observe the sea surface wind speed. Figure 4 shows an example of the blended winds where Hurricane Katrina, in the Gulf of Mexico, and Typhoon Talim, in the western Pacific Ocean, are clearly shown.

line graph showing sampling interval by latitude
Figure 3
click on image for larger view

Please note that these are research products, thus, they are considered as experimental in nature. Users are encouraged to register to receive update notices and to provide comments.

global wind map for year 2005 on August 28 at 1200 UTC
Figure4 - click on image for larger view
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Data Access

Note: We encourage users to register to receive product update notices by e-mail.

The global 0.25° grid data are available in netCDF and IEEE format for the period of record, July 1987 to present, with time resolutions of 6-hourly, daily, and monthly. There is also a 11-year (1995-2005) monthly climatological data set. Users can use the data with support reading programs in FORTRAN, MATLAB, and GrADS. The data servers below will also allow users to subset, visualize and download data in many formats (e.g. text, graphics, etc.) Users can access the data files via the following methods:

  • Anonymous FTP:
    • Internet Browser Access
    • Or, UNIX method
      login as anonymous
      password is your email address
      cd /pub/seawinds (there will be a README file along with subdirectories.)
  • The Live Access Server allows you to select, subset, manipulate, and visualize the data, and download the selected data in various formats (text/ascii, netCDF, graphics such as GIF, etc). [Note: for some functions (e.g., "Show Values"), you may need to click on that tab the 2nd time to get results.]
  • The OPeNDAP/THREDDS Data Server/Catalog allows you to subset and aggregate data from multiple data files, or open/transfer the data on the fly to your applications (e.g., in MAT LAB, GrADS, etc.)

Top of Page Disclaimer for the near-real-time products (NRT)

A version of NRT (about a 24-hour delay) Blended Sea Winds is produced quasi-daily to satisfy the needs of some users. Since the updates are done automatically under a non-operational environment (no 24/7 IT support), timely production is not guaranteed. Also, please note that the NRT data are replaced by the delayed-mode research quality data (Version 1.2) on a monthly basis. The data archive locations are the same for both the NRT and Research Quality products. File naming conventions are very similar, i.e. (NRT with 'rt'=real time) and (Research Quality - ver 1.2).

Update Oct. 6, 2011: Seawinds production has been impacted because of the loss of data from the AMSR-E instrument. Input data from two additional satellites (SSMI F15 ver.6 and F17 ver.7) are now added to the experimental near-real-time Blended Sea Winds. Users should exercise caution until the characteristics of the modified Seawinds product have been established. Aqua/AMSR-E press release.

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Frequently Asked Questions

Please check out the FAQ file and the Readme file. Should you have further questions, please contact

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Zhang, H.-M., J.J. Bates, and R.W. Reynolds, 2006: "Assessment of composite global sampling: Sea surface wind speed". Geophysical Research Letters, VOL. 33, L17714, doi:10.1029/2006GL027086.

Zhang, H.-M., R.W. Reynolds, and J.J. Bates, 2006: "Blended and Gridded High Resolution Global Sea Surface Wind Speed and Climatology from Multiple Satellites: 1987 - Present". American Meteorological Society 2006 Annual Meeting, Paper #P2.23, Atlanta, GA, January 29 - February 2, 2006.

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Dr. Huai-Min Zhang
NOAA/NESDIS/National Climatic Data Center
151 Patton Ave
Asheville, NC 28801
Phone: 1+828-271-4090 or -4850 x 3183
FAX: 1+828-271-4328