SeaWinds on QuikSCAT Level 3 Sigma-0 Polar-Stereographic Local-Time-of-Day Browse Maps of Antarctic Region
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|Description||This dataset contains polar-stereographic-gridded Sigma-0 retrievals over the Anarctic Polar region from SeaWinds on QuikSCAT retrievals subsetted and averaged twice daily at the local time-of-day (LTOD); local times are approximately morning (04:00 to 12:00 local) and afternoon (12:00 to 20:00 local). The eight hour interval at each LTOD reference of morning vs. afternoon corresponds to the natural boundaries of time separation within the data at polar latitudes. Hence, morning and afternoon are used as approximations for the LTOD reference, where the actual LTOD may vary within the respective 8 hour interval. This dataset is generated using a Scatterometer Image Reconstruction (SIR) technique developed by Dr. David Long at Brigham Young University (BYU); the processed files are therefore known as SIR files. These SIR files were also used to generate a complimentary dataset of GIF images meant for browse purposes only and is available here: http://podaac.jpl.nasa.gov/dataset/QSCAT_BYU_L3_OW_SIGMA0_ANTARCTICA_POLAR-STEREOGRAPHIC_BROWSE_IMAGES_LTOD. The QuikSCAT scatterometer scans at two nominal incidence angles, 46 degrees and 54.1 degrees, corresponding to the inner and outer beams respectively. The inner beam is horizontally polarized while the outer beam is vertically polarized. The SIR files are separated according to polarization. For example, one SIR file for a particular day and LTOD will contain the gridded average Sigma-0 values for the horizontally polarized L1B retrievals, while the other will contain those from the vertically polarized L1B retrievals. This dataset is generated by the Scatterometer Climate Record Pathfinder (SCP) project at BYU.|
|Measurement||SPECTRAL/ENGINEERING > RADAR > SIGMA NAUGHT > Normalized Radar Cross-Section|
CRYOSPHERE > SEA ICE > ICE EXTENT
Northernmost Latitude: -70 degrees
Southernmost Latitude: -89.6 degrees
Westernmost Longitude: 0 degrees
Easternmost Longitude: 360 degrees
Time Span: 1999-Jul-19 to 2009-Nov-21
|Resolution||Spatial Resolution: 0.201 degrees (Latitude) x 0.201 degrees (Longitude)|
Temporal Resolution: 12 Hour
Ellipsoid: WGS 84
Name: QUIKSCAT (QUIKSCAT)
Orbit Period: 100.93 minutes
Inclination Angle: 98.6 degrees
Ascending Node: 1999-Jul-19 06:04:49
Name: SeaWinds Scatterometer (SEAWINDS)
Swath Width: 1800 km
Description: SeaWinds is a Ku-band (13.4 GHz) Scatterometer which features a single circular scanning dish antenna to provide pencil-beam measurements, as opposed to the common fan beam design as seen with other spaceborne scatterometers. The pencil-beam design has several key advantages over the more common fan beam design: higher signal-to-noise ratio, smaller size, and superior coverage. The SeaWinds single antenna utilizes twin offset feeds, thus providing two pencil-beam footprint paths with an elliptical sampling footprint of approximately 25 km (in azimuth) by 37 km (in look/range direction); these pencil beams have opposing polarizations (i.e., vertical and horizontal), thus achieving dual-polarization. The SeaWinds instrument provides a full 1800 km-wide swath coverage (including the nadir region), which allows for a nominal daily measurement coverage of 90% over the ice-free oceans.
|Project||Scatterometry Climate Record Pathfinder (SCP)|
|Data Provider||Creator: BYU/SCP|
Release Place: PO.DAAC
Release Date: 2012-Mar-21
|Keyword(s)||sigma-0, sigma0 browse, sigma0, browse, backscatter, sir, byu, ltod, local-time-of-day, local time of day, scp, david long|
Questions related to this dataset? Contact email@example.com
|Format (Compression)||RAW (GZIP)|
|Citation||BYU/SCP. 2012. SeaWinds on QuikSCAT Level 3 Sigma-0 Polar-Stereographic Local-Time-of-Day Browse Maps of Antarctic Region. Ver. 1. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/QSBYU-ANBLT.
For more information see Data Citations and Acknowledgments.
|Journal Reference||Hicks, B. R. and D. Long. March, 2005. Improving temporal resolution of SIR images for QuikSCAT in the polar regions. Technical Report MERS 05-02. Microwave Earth Remote Sensing Laboratory, Brigham Young University, Provo, UT.|