 |
L2B Ocean Wind Vectors (25km) in Swath Grid |
|
|
|
|
Abstract
References |
|
Product 108 |
|
|
|
|
|
|
Abstract |
|
|
ab108
Source/sensor: SeaWinds on QuikSCAT
Coverage: 1999-present, global
The SeaWinds on QuikSCAT Level 2B data set consists of wind vector solutions for all four wind vector ambiguities as well as the Direction Interval Retrieval with Threshold Nudging (DIRTH) wind vector solution. Each Level 2B file contains data for one full orbital revolution of the spacecraft or 'rev'. These data are grouped by rows of 25km wind vector cells (WVC). Each row contains a total of 76 WVC values and corresponds to a single cross-track cut of the SeaWinds swath. 1624 wind vector cell rows are required to complete a rev. Data are currently available in Hierarchical Data Format (HDF) and exist from 19 July 1999 to present.
The Level 2B data are derived from QuikSCAT Level 2A sigma-0 measurements. When rain is present, the measurements of the ocean surface sigma-0 are affected in several ways. The radar signal may be scattered by the raindrops and never reach the ocean's surface. The radar signal may be attenuated by the rain as it travels to and from the earth's surface. The roughness of the sea surface due to the splashing of the raindrops may also affect the sigma-0 measurement and thus the wind vector solution. In an effort to indicate the presence of rain, the Level 2B data include the Multidimensional Histogram Rain Flag SDS (mp_rain_probability) and the Normalized Objective Function Rain Flag SDS (nof_rain_index). In addition, wvc_quality_flag bit 13 indicates whether or not the rain flag algorithm indicates rain.
These data are available via anonymous FTP to podaac.jpl.nasa.gov in the pub/ocean_wind/quikscat directory. The data may also be ordered on 8mm exabyte tape in LINUX Tar using the PO.DAAC on-line order form (http://podaac.jpl.nasa.gov/order/order_qscat.html). Documentation, read software, and further information may also be obtained from the PO.DAAC QuikSCAT Web site (http://podaac.jpl.nasa.gov/quikscat/).
Data Set Volume: One file is approximately 2MB compressed.
Smallest order: One file via FTP.
Standard Product: FTP
Data Format:HDF
Media Format: These data are available via FTP to podaac.jpl.nasa.gov, on 8mm EXABYTE tape in LINUX TAR. |
|
|
|
References |
|
|
ci108
References:
- Dunbar, R.S., S.V. Hsiao, and B.H. Lambrigtsen, Science Algorithm Specifications for the NASA Scatterometer Project, JPL D-5610 (597-521), Vol. 1 (Sensor Algorithms) and Vol. 2 (Geophysical Algorithms). Issued May 1988, last updated November 1991.
- Freilich, M.H., and R.S. Dunbar, "A Preliminary C-Band Scatterometer Model Function for the ERS-1 AMI Instrument," Proceedings of the First ERS-1 Symposium: Space at the Service of our Environment, Cannes, 4-6 November 1992, ESA SP-359, European Space Agency, Paris.
- Naderi, F.M., M.H. Freilich, and D.G. Long, "Spaceborne Radar Measurement of Wind Velocity Over the Ocean - An Overview of the NSCAT Scatterometer System," Proc. IEEE, 79, 6, June 1991.
- Shaffer, S., R.S. Dunbar, S.V. Hsiao, and D.G. Long, "A Median-Filter-Based Ambiguity Removal Algorithm for NSCAT," IEEE Trans. Geosci. Remote Sens., 29, 1991.
- Tsai, W., J.E. Graf, C. Winn, J.N. Huddleston, R.S. Dunbar, M.H. Freilich, F.J. Wentz, D.G. Long, and W.L. Jones, "Postlaunch Sensor Verification and Calibration of the NASA Scatterometer," IEEE Trans. Geosci. Remote Sens., vol. 37, pp. 1517-1542, May 1999.
- Weiss, B., "Level 1B Data Software Interface Specification (SIS-2)", Internal JPL SeaWinds Project Document 686-644-1 Rev A, JPL Document D-16077, January 2000.
- Weiss, B., "Level 2A Data Software Interface Specification (SIS-2)", Internal JPL SeaWinds Project Document 686-644-2 Rev A, JPL Document D-16078, April 2000.
- Weiss, B., "Level 2B Data Software Interface Specification (SIS-2)", Internal JPL SeaWinds Project Document 686-644-3 Rev B, JPL Document D-16079, April 2000.
- Wentz, F.J., "Climatology of 14 GHz Atmospheric Attenuation," Remote Sensing Systems Tech. Memo 052096, May 1996.
- Zhang, A., R.S. Dunbar, S.V. Hsiao, K. Pak, Y. Kim, "Science Algorithm Specifications for SeaWinds," Internal JPL SeaWinds project document, 1996, 1999.
Collections:
- "NSCAT: Scientific Applications," American Geophysical Union collection of NSCAT papers reprinted from J. Geophys. Res., Geophys. Res. Letters, Eos, Transactions, AGU, 1999.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
