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)