Cross-Calibrated Multi-Platform (CCMP) Ocean Surface Wind Components

6-Hourly

In collaboration with private and government institutions, a team led by Dr. Robert Atlas (PI; proposal originally solicited by REASoN, and currently funded by MEaSURES through NASA) has created a cross-calibrated, multi-platform (CCMP), multi-instrument ocean surface wind velocity data set, for the period extending from July 2, 1987 through December 31, 2011, with wide ranging research applications in meteorology and oceanography. This product was a result of an investigation funded by NASA's Making Earth Science data records for Use in Research Environments (MEaSUREs) Program.
It represents a continuation and expansion of the SSM/I surface wind velocity data set that began under the NASA Pathfinder Program (see http://podaac.jpl.nasa.gov/PRODUCTS/p079.html). This data set combines data derived from SSM/I, AMSRE, TRMM TMI, Quikscat and other missions using a variational analysis method (VAM) to produce a consistent climatological record of ocean surface vector winds at 25km resolution. The VAM requires a background (first guess) analysis of gridded U and V winds as a starting estimate of the wind field. Analysis increments are added to this background to arrive at the final analysis. Background analyses for the ‘first-look’ (FLK) products utilize the ECMWF Operational Analysis (DS111.1), which are obtained from the Computation and Information Systems Laboratory (CISL) at the National Center for Atmospheric Research (NCAR): http://dss.ucar.edu/datasets/ds111.1/. The next addition to the CCMP will be the ‘late-look’ (LLK) products, which may incorporate bias correction to the ECMWF background wind vector field and ocean wind vector data from new satellite missions.
The methodology that is used to generate the CCMP has been previous published by Atlas et al. (1996) and is similar to that described by Hoffman (1984), with modifications to accommodate special attributes of the satellite surface wind data as well as some additional tuning of the data quality checking and filter weights.
Satellite surface wind data are obtained from Remote Sensing Systems (RSS) under the DISCOVER project: Distributed Information Services: Climate/Ocean Products and Visualizations for Earth Research (http://www.discover-earth.org/index.html). RSS uses a more accurate sea-surface emissivity model resulting in much better consistency between wind speed retrievals from microwave radiometers (SSM/I, AMSR, TMI) and those from scatterometers (NSCAT and SeaWinds). All observations are referenced to a height of 10 meters.
The primary data set, denoted Level 3.0, contains 6-hourly gridded V AM analyses. The 6-hourly VAM analyses are centered at 0,6,12 and 18z. These analyses are time averaged over 5-day (pentad) 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 in order to more accurately approximate a satellite-only climatology. The pentad means start on the first day of each year. In leap years, the pentad starting on 2/26 will include 6-days such that the starting date for each pentad remains the same across all years. The monthly means start on the first day of each month.

Reference:
Atlas, R., R. N. Hoffman, S. C. Bloom, J. C. Jusem, and J. Ardizzone, 1996: A multiyear global surface wind velocity data set using SSM/I wind observations. Bull. Amer. Meteor. Soc., 77, 869–882.

Hoffman, R. N.s, 1984: SASS wind ambiguity removal by direct minimization. Part II: Use of smoothness and dynamical constraints. Mon. Wea.Rev., 112, 1829–1852.

Variables
Number of observations (count)
U-wind at 10 meters (m/s)
V-wind at 10 meters (m/s)
ZonalGlobal by 0.25 deg
Meridional78.5S to 78.5N by 0.25 deg
VerticalSurface  
Temporal Jul 02, 1987 to Dec 31, 2011 by 6 hour(s)
Static? yes
Volume14MB per variable per day
Serverpublic:
SourcePO.DAAC
Acquired Aug 19, 2009 (Updated Dec 2013)
APDRC contact
Supplements Users_guide