The PO.DAAC is pleased to announce the release of the "Oceansat-2 Scatterometer Level 2B Ocean Wind Vectors in 12.5 km Slice Composites Version 2" dataset produced by the QuikSCAT Project at the Jet Propulsion Laboratory (JPL) in cooperation with the Indian Space Research Organization (ISRO). This dataset consists of the version 2 Level 2B (L2B) science-quality ocean surface wind vector retrievals from the Oceansat-2 scatterometer (OSCAT), which was designed and launched by ISRO on 23 September 2009. The current dataset time series extends from 16 January 2010 to 6 March 2013; new data will be provided on an approximate monthly basis. The L2B data is provided on a non-uniform grid within the swath at 12.5 km pixel resolution. This resolution is achieved through a slice composite technique in which high-resolution slice measurements from L1B data are composited into a 12.5 km wind vector cell. This version contains an improved geophysical model function (GMF), known as QSCAT12 (Fore et al., 2013; Jaruwatanadilok et al., submitted 2013), consistent with the Remote Sensing Systems Ku2011 GMF (Meissner et al. 2011), and improved rain detection and flagging algorithm; these algorithms are also consistent with the latest reprocessed version 3 QuikSCAT L2B dataset. Each L2B file corresponds to a specific orbital revolution number, which begins at the southernmost point of the ascending orbit. As a Ku-band dual pencil-beam rotating scatterometer, OSCAT design specifications bear a strong resemblance to the Ku-band SeaWinds scatterometers on QuikSCAT and Midori-II (ADEOS-II). The primary difference between OSCAT and SeaWinds is the ~4 degree increase in the OSCAT incidence angle, which acts as an offset to the lower altitude of Oceansat-2 to help provide a nearly identical swath width to SeaWinds. In the early cal/val phase, the JPL QuikSCAT Project identified several problems, most of which have been corrected in this L2B version.
This dataset is expected to have accuracy similar to that of the version 3 QuikSCAT L2B dataset, with minor caveats all of which are described in the User Guide document. The data has also been cross-calibrated with QuikSCAT as described by Jaruwatanadilok et al (submitted, 2013). Both documents are made available here: ftp://podaac.jpl.nasa.gov/allData/oceansat2/L2B/oscat/jpl/docs.
Read software is made available in MATLAB, Python, R and IDL and is accessible here: ftp://podaac.jpl.nasa.gov/allData/oceansat2/L2B/oscat/jpl/sw.
Data files are provided in a CF-compliant, netCDF version 4 format, accessible at: ftp://podaac.jpl.nasa.gov/allData/oceansat2/L2B/oscat/jpl/v2/.
The primary dataset information page is provided through our web portal at: http://podaac.jpl.nasa.gov/dataset/OS2_OSCAT_LEVEL_2B_OWV_COMP_12_V2
Should you have any questions or wish to provide feedback on this dataset, please contact us at: podaac@podaac.jpl.nasa.gov
References:
[1] Fore, A.G., Stiles, B.W., Chau, A.H., Williams, B.A., Dunbar, R. S.,
Rodríguez E., 2013: Point-wise Wind Retrieval and Ambiguity Removal
Improvements for the QuikSCAT Climatological Data Set. Accepted for
publication in IEEE Trans. Geoscience and Remote Sensing,
doi:10.1109/TGRS.2012.2235843, 2013.
[2] T. Meissner, L. Ricciardulli, and F. Wentz, 2011: All-weather wind vector measurements from intercalibrated active and passive microwave satellite sensors. Geoscience and Remote Sensing Symposium (IGARSS), 2011 IEEE International. July 2011. pp. 1509 –1511.
[3] S. Jaruwatanadilok, B. W. Stiles, and A.G. Fore, submitted: Cross calibration between QuikSCAT and OceanSAT-2. Submitted to IEEE Trans. Geoscience and Remote Sensing, 2013.