SeaWinds on QuikSCAT Level 3 Sigma-0 Polar-Stereographic Local-Time-of-Day Browse Images of Arctic Region

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DOI	10.5067/QSBYU-ARILT
Short Name	QSCAT_BYU_L3_OW_SIGMA0_ARCTIC_POLAR-STEREOGRAPHIC_BROWSE_IMAGES_LTOD
Description	This dataset contains GIF images of polar-stereographic-gridded Sigma-0 retrievals over the Antarctic Polar region from SeaWinds on QuikSCAT retrievals subsetted and averaged twice daily at the local time-of-day (LTOD); local times are approximately morning (00:00 to 08:00 local) and evening (16:00 to 24:00 local). The eight hour interval at each LTOD reference of morning vs. evening corresponds to the natural boundaries of time separation within the data at polar latitudes. Hence, morning and evening are used as approximations for the LTOD reference, where the actual LTOD may vary within the respective 8 hour interval. It should be noted that these GIF images are meant for browse purposes only and should not be considered science quality. The GIF images are generated from a scientific dataset employing a Scatterometer Image Reconstruction (SIR) technique developed by Dr. David Long at Brigham Young University (BYU); the science quality source dataset containing the SIR files used to generate the GIF images is accessible here: http://podaac.jpl.nasa.gov/dataset/QSCAT_BYU_L3_OW_SIGMA0_ARCTIC_POLAR-STEREOGRAPHIC_BROWSE_MAPS_LTOD. The SeaWinds 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. As with the SIR files, the GIF images are separated according to polarization. For example, one SIR file for a particular day and LTOD will contain the gridded average Sigma-0 values derived from 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.
Version	1
Dataset Type	OPEN
Measurement	Spectral/Engineering > Radar > Sigma Naught > Normalized Radar Cross-Section Cryosphere > Sea Ice > Ice Extent
Processing Level	3
Coverage	Region: Arctic Northernmost Latitude: 89.6 degrees Southernmost Latitude: 70 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
Projection	Type: Gridded Detail: Polar-Stereographic Ellipsoid: WGS 84
Latency	hours
Platform/Sensor	QUIKSCAT Platform Name: QUIKSCAT (QUIKSCAT) Orbit Period: 100.93 minutes Inclination Angle: 98.6 degrees Ascending Node: 1999-Jul-19 06:04:49 / SEAWINDS SENSOR 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 Resource: https://podaac-tools.jpl.nasa.gov/drive/files/allData/quikscat/L3/byu_scp/sigma0browse/docs/dLongSigBrw.pdf
Keyword(s)	sigma-0, sigma0 browse, sigma0, browse, backscatter, sir, byu, ltod, local-time-of-day, local time of day, scp, david long
Persistent ID	PODAAC-QSBYU-ARILT

Questions related to this dataset? Contact podaac@podaac.jpl.nasa.gov

PO.DAAC DRIVE	https://podaac-tools.jpl.nasa.gov/drive/files/allData/quikscat/L3/byu_scp/sigma0browse/images/arctic_ltod
Format (Compression)	GIF (NONE)

Citation

BYU/SCP. 2012. SeaWinds on QuikSCAT Level 3 Sigma-0 Polar-Stereographic Local-Time-of-Day Browse Images of Arctic Region. Ver. 1. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/QSBYU-ARILT.

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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.