The Cross-Calibrated Multi-Platform (CCMP) Ocean Surface Wind Components (Atlas et al. 2008, 2009) time series has been extended through June 30, 2009. This additional 6 months of data extends the CCMP climate data record (CDR) to a full 22 years, starting on July 1, 1987.
The CCMP data product is derived through cross-calibration and assimilation of ocean surface wind data from SSM/I, TMI, AMSR-E, SeaWinds on QuikSCAT, and SeaWinds on ADEOS-II. Cross calibration is performed by Remote Sensing Systems (RSS) under the DISCOVER project (http://www.remss.com/). These data sets are combined with conventional observations and a starting estimate of the wind field using a variational analysis method (VAM). The ECMWF Reanalysis (ERA-40) is used as the starting estimate (or background) for July 1987 until December 1998 and the ECMWF Operational Analysis is used from January 1999 onward.
CCMP consists of three unique data sets, each of which is stored on a uniform grid with a resolution of 0.25°x0.25°. The principal data set, denoted Level 3.0, contains gap-free wind vector analysis fields every six hours (initialized at 00 GMT) in its near global (78.375°S to 78.375°N) domain. These analyses are time averaged over 5-day and monthly periods to derive the Level 3.5 data sets. For level 3.5a data sets, only those grid points with one or more analyzed observations are used in the averages to more accurately approximate a satellite-only climatology. A level 3.5b data set, which shall make use of all analysis points, will soon be available. Finally, directions from the VAM analyses are assigned to the wind speed observations for each passive microwave sensor to derive the Level 2.5 data sets. Level 2.5 data is available in a binary Bytemap format to parallel the original satellite data files from RSS.
CCMP is the culmination of nearly a decade of work beginning with NASA's SSM/I Pathfinder program which led to the production of the SSM/I Derived Ocean Surface Wind Components dataset (Atlas et al. 1996). The success of this project led to more funding through REASoN to begin work on multi-satellite data assimilation from SSM/I, TMI, AMSR-E, SeaWinds on QuikSCAT, and SeaWinds on ADEOS-II. NASA's Making Earth Science data records for Use in Research Environments (MEaSUREs) program is currently funding the CCMP project to extend its CDR time series to 2012. The current series of CCMP products is known as First-Look (FLK). A Late-Look (LLK) product is expected to be ready after 2011. The LLK product will include additional cross-calibrated data sets (such as WindSat, NSCAT, and ASCAT) and other enhancements.
CCMP has been evaluated and utilized extensively by the science community, including some members of NASA's Ocean Vector Winds Science Team (OVWST). PO.DAAC's "Product Preview" allowed for the opportunity for all users to evaluate the CCMP product for a full year before its final release on May 11, 2009.
To learn more and access the CCMP datasets, please visit our web portal: http://podaac.jpl.nasa.gov/DATA_CATALOG/ccmpinfo.html.
Disclaimer: All CCMP datasets represent an "analysis" (as opposed to an observation) which is the result of a combined assimilation and cross-calibration of instrument measurements and numerically-derived analyses from ECMWF. For more information on how these products were derived, as well as known problems, please download the user guide (please note that the user guide may be updated periodically): ftp://podaac.jpl.nasa.gov/ocean_wind/ccmp/L3.0/doc/ccmp_users_guide.pdf.
If you have any comments or questions, please email us at podaac@podaac.jpl.nasa.gov.
Respectfully,
PO.DAAC User Services
Citations:
[1] Atlas, R., R.N. Hoffman, S.C. Bloom, J.C. Jusem, and J. Ardizzone, 1996: A multiyear global surface wind velocity dataset using SSM/I wind observations. BAMS, 77, 5, 869-882.
[2] Atlas R., Ardizzone J., Hoffman R.N., 2008: Application of satellite surface wind data to ocean wind analysis, Proc. SPIE, Vol. 7087, 70870B (2008); DOI:10.1117/12.795371.
[3] Atlas R., Hoffman R. N., Ardizzone J., Leidner S. M., Jusem J. C., 2009: Development of a new cross-calibrated, multi-platform (CCMP) ocean surface wind product. AMS 13th Conference on Integrated Observing and Assimilation Systems for Atmosphere, Oceans, and Land Surface (IOAS-AOLS)
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