NSCAT Information

Products / Announcements / Documentation / Known Problems & Issues / FAQs / Related Publications / Acronyms

Mission
The NASA Scatterometer (NSCAT) was launched at 6:54 p.m. U.S. PDT, Friday, August 16, 1996 aboard the Advanced Earth Observing Satellite (ADEOS). The NSCAT mission ended prematurely due to a power loss aboard ADEOS on June 30, 1997. The launch itself was directed by the National Space Development Agency (NASDA) of Japan. Data retrieval, calibration and validation was carried out by the NSCAT project scientists at JPL/NASA in cooperation with NASDA. NSCAT transmits microwave pulses and receives backscattered power from the ocean surface, which is used to derive the normalized radar cross section (sigma-0). Using a calibrated model function, the sigma-0 is used to derive all-weather, high-resolution ocean surface wind vector measurements throughout the global oceans. NSCAT provided coverage at 90% of the global ice-free oceans every two days.

NSCAT Level 3 ocean wind vectors over the Pacific Ocean.
Measurements observed during June 25-27, 1997.
Click here for details.

NSCAT Table

Products

	FTP HEFT	s/w	Y	N	Y	Y	Y	N	Daily	0.5°
Documentation: User Manual / Related Publications	Comments:	Gridded on a LAT/LON projection. Wind vectors are averaged in locations where swaths overlap during the span of 1 day; 2 days provides full global coverage. Files are organized in 7-day batches, where each file contains 1 daily average of global ocean wind vectors.

	FTP HEFT	s/w	Y	N	N	N	Y	Y		50 km
Documentation: User Manual / Related Publications	Comments:	Derived from sigma-0 grouped into wind vector cells (WVC). Files are organized in 7-day batches, where each file contains 1 orbital revolution (rev). There are approximately 14 revs per day.

	FTP HEFT	s/w	Y	Y	N	N	N	N		25 km, 50 km
Documentation: User Manual / Related Publications	Comments:	Up to 24 sigma-0 backscatter measurements available per wind vector cell (WVC). Cross-track resolution is 25km; WVC resolution is 50 km. Files are organized in 7-day batches, where each file contains 1 orbital revolution (rev). There are approximately 14 revs per day.

	FTP HEFT	s/w	Y	Y	N	N	Y	Y		25 km
Documentation: User Manual / Related Publications	Comments:	Sigma-0 and wind vector data are co-located in 25 km wind vector cells (WVC). Files are organized in 7-day batches, where each file contains 1 orbital revolution (rev). There are approximately 14 revs per day.

	FTP-SIR FTP-GRD V-POL H-POL	s/w	Y	Y	N	N	N	N	Daily	4.5 km, 22.25
Documentation: User Manual / Related Publications	Comments:	Data access direct from BYU. Data are organized according to region. Scatterometer image reconstruction with filtering (SIRF) is used to create the "enhanced" resolution (4.5 km) SIR images. The "gridded" (non-enhanced) data (GRD) are provided at 22.5 km resolution. Vertically polarized sigma-0 (V-POL) data is available under the /nscv directory; horizontally polarized sigma-0 (H-POL) is available under the /nsch directory. The V-POL and H-POL links direct you to browse images only.

Announcements
The NSCAT mission has ended as of June 30, 1997.

Documentation
BYU Sigma-0 Browse Methodology

NSCAT User's Manual (L1.7, L2, L3)

NSCAT High-Resolution Merged Geophysical Data Product User's Guide

Known Problems and Issues
Backscatter is contaminated in rainfall events and within close proximity to land/ice boundaries. The wind model function has a tendency to underestimate high wind speeds; there is also insufficient information (i.e. poor signal-to-noise ratio) during calm seas (i.e. where actual wind speeds are less than 1 m s-1).

Frequently Asked Questions
NSCAT FAQ's

Related Publications
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.

Early, D.S. and D.G. Long, Feb 2001. "Image Reconstruction and Enhanced Resolution Imaging From Irregular Samples", IEEE Transactions on Geoscience and Remote Sensing, Vol. 39, No.2, pp. 291-302.

Long, D.G. and M.R. Drinkwater, 1999. "Cryosphere Applications of NSCAT Data", IEEE Transactions on Geoscience and Remote Sensing, Vol. 37, No. 3, pp. 1671-1684.

Long, D.G., P. Hardin, and P. Whiting, 1993. "Resolution Enhancement of Spaceborne Scatterometer Data", IEEE Transactions on Geoscience and Remote Sensing, Vol. 31, pp. 700-715.

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", Proceedings of the IEEE, 79, 1 Jan. 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.

Wentz, F.J., "Climatology of 14 GHz Atmospheric Attenuation," Remote Sensing Systems Tech. Memo 052096, May 1996.