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SCIENCE PROCESSING OVERVIEW
David Le VineAquarius Deputy PI
07 July 2009
Data Product Description
Level 1A Reconstructed unprocessed instrument data
Level 1B* Geolocated, calibrated radiometer sensor units acquired at 0.12 second instrument cycle; Averaged and retained at 1.44 seconds.
Geolocated, calibrated scatterometer sensor units acquired at 0.18 second instrument cycle; Averaged and retained at 1.44 seconds.
Level 2A Geolocated, calibrated radiometer and scatterometer sensor units at 1.44 s sample at the surface, corrected for Faraday rotation, antenna pattern, atmosphere and sky reflections.
Level 2B Geolocated SSS from L2A at 1.44 sec. Roughness correction (TB) from Scatterometer.
Level 3 Time-space objectively analyzed SSS on a standard Earth Projection with150 km smoothing scales; 7-days and monthly.
Data Definitions
Data Files
* RFI and Glitch detection filters
Aquarius/SAC-DCONAE
L1A: FormattingEphemeris/Time
Geolocation
Average: 1.44 sec
RFI Filter
L2B File
SSS Retrieval
To L3
Geophysical Algorithm Remove Sky
APCFaraday Rotation
Propagate to SurfaceTB at surface
Science Ground Processing Flow Diagram
L2A: Scatterometer
Geophysical Algorithm
Calibrated Sigma0
Average <1.44sec>
Gain GlitchDetector
CalibrationCounts TA
Temp correction
Radiometer Calibration
TA To L2B File
Faraday RotationAlternative: IGS
L2A
L2B: Wind or ΔTB
Ancillary DataNCEP and SST
Solar FluxIGS
Land MaskGalactic Background
Flags
L1B: ScatterometerCalibration
RFI / Ice Flags
TB surface
L1B To L2B File
Cal/ValAVDS
Cold SkyL2B
Aquarius/SAC-DCONAE
L1A: FormattingEphemeris/Time
Geolocation
Average: 1.44 sec
RFI Filter
L2B File
SSS Retrieval
To L3
Geophysical Algorithm Remove Sky
APCFaraday Rotation
Propagate to SurfaceTB at surface
Science Ground Processing:
L2A: Scatterometer
Geophysical Algorithm
Calibrated Sigma0
Average <1.44sec>
Gain GlitchDetector
CalibrationCounts TA
Temp correction
Radiometer Calibration
TA To L2B File
Faraday RotationAlternative: IGS
L2A
L2B: Wind or ΔTB
Ancillary DataNCEP and SST
Solar FluxIGS
Land MaskGalactic Background
Flags
L1B: ScatterometerCalibration
RFI / Ice Flags
TB surface
L1B To L2B File
Cal/ValAVDS
Cold SkyL2B
Implemented blocks
Science DocumentationAlgorithm Theoretical Basis Documents: ATBD
• Radiometer:– L1B: Geolocation
• Delivered
– L2A and L2B: SSS Retrieval Algorithm
• Delivered (Update, January, 2008)• Revision : October, 2009
• Scatterometer– L1 and L2: Due May, 2010
• Level 3: Gridding– Delivered
Data Product Description
Level 1A Reconstructed unprocessed instrument data
Level 1B Geolocated, calibrated radiometer sensor units acquired at 0.12 second instrument cycle; Averaged and retained at 1.44 seconds.
Geolocated, calibrated scatterometer sensor units acquired at 0.18 second instrument cycle; Averaged and retained at 1.44 seconds.
Level 2A Geolocated, calibrated radiometer and scatterometer sensor units at 1.44 s sample at the surface, corrected for Faraday rotation, antenna pattern, atmosphere and sky reflections.
Level 2B Geolocated SSS from L2A at 1.44 sec. Roughness correction (TB) from Scatterometer.
Level 3 Time-space objectively analyzed SSS on a standard Earth Projection with150 km smoothing scales; 7-days and monthly.
Data Files
Radiometer Flags• RFI: Wentz/Ruf
– Based on algorithm by C. Ruf– Code provided by F. Wentz– Input: Calibrated radiometer TA
• Rain: Wentz– Flags rain in main beam and corrects for liquid water– Input: NCEP rain and/or MWR– Status: research needed to use MWR and/or improve product
• Land: Wentz – Generates a weighted land fraction (land fraction weighted by the antenna pattern)– Input: Antenna patterns and orbit geometry
• Ice : Le Vine– Generates a weighted ice fraction– Input: Antenna patterns, orbit geometry and sea ice data (TBD)– Research needed to determine appropriate source of sea ice data.
• Wind Speed– Generates a flag level of wind (e.g. W < 7 m/s; 7 < W < 15; W > 15 m/s)– Input: Same windspeed as used in the SSS retrieval (NCEP, MWR, or Scatt)
• Unusual TB– Compares measured TB with forward model and flags outliers– Input: Actual SST and reference SSS (e.g. smoothed Argo field, or HYCOM output)– Use TB at surface (but TB at TOA or TOI are also possible)
Flags Continued 1• Sun1: Mean Sun; Le Vine
– Computes TA due to sun and issues a level (Green, yellow, red) to indicate potential contamination
– One flag for direct and one for reflected ray– Input: Noon time solar flux from Air Force RSTN station at Sagamore Hill plus antenna
patterns• Sun2: Solar Flare; Le Vine
– Computes TA due to solar flares and issues a level (Green, yellow, red) to indicate potential problem
– One flag for direct ray and one for reflected ray.– Input: RSTN data on solar microwave bursts at L-band.
• Sun3: Illuminated Ocean; Le Vine– Indicates times when small scale roughness may cause reflected sun to enter near the main
beam.– Three level flag– Input: Wind speed plus static look up table (this is will be computed using fixed parameters
as a function of wind speed using two scale model for the rough surface)• Moon: Le Vine
– Computes TA due to the Moon and issues a flag when the reflected ray approaches boresight (twice each month)
– Flag with three levels– Input: Static look up table based on orbit ephemeris
• Galactic: Le Vine– Computes the contribution of radiation from the galaxy scattered into the mainbeam.– There level flag– Input: Wind speed and SST and reference SSS. Rough surface and smooth surface look
up table.
Flags Continued 2• Gain Jump: Piepmeier
– Identifies gain glitches
– Yes or No
– Input: Radiometer output
Ancillary Data
• Land Mask: RSS or GSFC data base– 1/12 deg resolution (GSFC/MODIS at 1 km)– Either mask is acceptable. The difference should not matter.
• Galactic Background : Avialable at the Aquarius website– http://oceancolor.gsfc.nasa.gov/AQUARIUS/DinnatEtAl2009/galacticMap_docu.html
• Sun: The Air Force Radio Solar Telescope Network (RSTN) provide solar flux– Mean Value :
ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SOLARRADIO/FLUX/ USAF_NOON_FLUX/
– Flares: ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SOLAR_RADIO/BURSTS/
• Atmosphere (pressure, temperature and humidity profiles): – NCEP GFS GDAS (Operational Product with a 6-9 hour delay)– One degree resolution: ftp://ftpprd.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/
• Atmosphere: total liquid water– NCEP GFS GDAS (Operational product with 6-9 hour delay)– One degree resolution: ftp://ftpprd.ncep.noaa.gov/pub/data/nccf/com/gfs/prod– Also: MSP (SSM/IS brightness temperature from Remote Sensing Systems)– Also: MWR and/or GPM ?.
Ancillary Data: Cont• Sea Surface Temperature:
– NCEP OISST product (Reynolds)– Daily at 0.25 degree resolution– ftp://ftpprd.ncep.noaa.gov/pub/data/nccf/cmb/sst/oisst_v2/
• Sea Surface Winds: NCEP GDAS (Operational Product with a 6-9 hour delay)– ftp://ftpprd.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/ – Also: MWR and/or Scatterometer
• Sea Ice (Concentration, extent and age)– TBD: GSFC team (Le Vine) to research and define optimum product– Goal is to have a flag for ice contamination (weighted beam fraction)– Candidates:
• NOAA/MMB or NSIDC (DMSP product)• Daily (1-2 days delay; 12.7 km MMB or 25 km NSIDC)• http://www.nsidc.org (registration or subscription)• ftp://polar.ncep.noaa.gov/pub/ice/
• Ionosphere: Earth Magnetic Field– International Geomagnetic Reference Field (IGRF)– Code: http://www.ngdc.noaa.gov/IAGA/vmod/igrf10.f
• Ionosphere: Total Electron Content– IGS rapid product– ftp://cddis.gsfc.nasa.gov/gps/products/ionex/.
Backup
Data Product Description
Level 1A Reconstructed unprocessed instrument data
Level 1B Geolocated, calibrated radiometer sensor units acquired at 0.12 second instrument cycle; Averaged and retained at 1.44 seconds.
Geolocated, calibrated scatterometer sensor units acquired at 0.18 second instrument cycle; Averaged and retained at 1.44 seconds.
Level 2A Geolocated, calibrated radiometer and scatterometer sensor units at 1.44 s sample at the surface, corrected for Faraday rotation, antenna pattern, atmosphere and sky reflections.
Level 2B Geolocated SSS from L2A at 1.44 sec. Roughness correction (TB) from Scatterometer.
Level 3 Time-space objectively analyzed SSS on a standard Earth Projection with150 km smoothing scales; 7-days and monthly.
Data Definitions
Data Files
Schedule and Milestones• Simulated Data
– Radiometer• June 15: Tests file to Ground System (Done)• June 30: One week of data• July 1 – Aug 15: Continue sending data until complete (one year simulated)
– Scatterometer• July 1: Test file delivered (under review; updated July 31)• End of August: Start generation of 1 yr of simulated data (completed mid-September) • End of October: Deliver code for L2 algorithm• February 2010: L2 processor update
• Radiometer Software Update: October 30– Mods to Geophysical algorithm
• Move APC• Add galactic background (smoothed map)
– Complete radiometer calibration (Counts to TA)• June 30: Code & data delivered from instrument team to science team• October 30: Code delivered by science team to ground system.
– Add Flags• Updates to ground system and RSS as available• All flags ready to implement by October 30
• Things Remaining to be Added– Gain glitch filter – Roughness model for reflected galactic background– Sun correction when in daylight and when backscatter occurs from small scale roughness– Land correction (Land fraction will be flagged but no correction in the October code)