Improved Aquarius Salinity Retrievals using Auxiliary Products

from the CONAE Microwave Radiometer (MWR)

W. Linwood JonesCentral Florida Remote Sensing Lab (CFRSL)

Mónica Rabolli Comision Nacional De Actividades Espaciales (CONAE)

5th Aquarius/SAC-D Science Meeting21-23 October, 2009

Buenos Aires, Argentina

Research Objective

• To provide cal/val of the ocean salinity measurements provided by the Aquarius L-band radiometer/scatterometer– To develop L-band radiometric brightness

temperature correction algorithms for ocean surface roughness, precipitation and sea ice concentration that are based upon MWR observations

– To perform inter-satellite radiometric (brightness temperature) calibration between MWR and WindSat/TRMM Microwave Imager

CFRSL & CONAE Pre-Award Activities

– MOU in progress• Areas of Collaboration:

– Microwave remote sensing training– MWR radiometric calibration– Geophysical algorithm development

– Exchange of Personnel• CONAE: 3 engineers (4 man-weeks)• CFRSL Ph.D. student (5 weeks)

– CFRSL Fulbright scholar MS thesis• Inter-satellite radiometric calibration between MWR and WindSat• Simulated MWR data derived from WindSat

Technical Status

• Aquarius roughness correction based on MWR

• MWR rain retrieval algorithm

AQ Salinity Measurement (Tb) Error Budget

37 GHz

24 GHz

AQ Scatterometer Provides Baseline Roughness Correction

MWR can provide independent AQ roughness correction by retrieving surface wind speed and using L-band radiative transfer model

Simon Yueh, JPL

Alternative MWR to AQ Ocean Roughness Correction RTM

H-pol

V-pol

MWR can provide independent AQ roughness (Tb) correction by direct correlation

MWR Oceanic Rain Rate Retrieval

• Statistical Rain rate retrieval

• Based upon excess brightness temperature

• Trtm – radiation transfer model (NCEP input pars)

• Empirical Tex-RR relationship• Tuned to WindSat rain rate retrievals

),,( WVWSSSTTTT rtmmeasex

WindSat Tmeas

RTM TB Tex

Tex for WindSat SDR: 37GHz H-Pol

kelvin kelvin kelvin

WindSat Rain Rate

Tex for 37 GHz V-POL

Tex for 37 GHz H-POL

Tex for 23 GHz V-POL

Excess-TB and SRR Relationship

kelvin

kelvin

mm/hr

kelvin

ΔTex-IRR RelationshipΔ

TB,

Kel

vin

ΔT

B,

Kel

vin

ΔT

B,

Kel

vin

Integrated Rain Rate, km*mm/hr

23.8 GHz V-Pol

37 GHz V-Pol

37 GHz H-Pol

Weighted Average IRR

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IRRkIRRjIRRiIRR VVH

trieval

8.235.365.36Re

Potential AQ Rain Rate Correction Issue

• Rain attenuation introduces negligible Tb error

• However, for convective rain cells, associated ocean roughness effects may result

• Post-launch we will collect 3-way AQ, MWR and TRMM Precipitation Radar match-ups to assess effect

Synthetic Aperture Radar Backscatter Image of Tropical Rain Cells

Scale: 25 km

Future Pre-launch Activities

• MWR radiometric calibration– Deliver to CONAE independent analysis of TV

radiometric calibration

– Deliver to CONAE post-launch radiometric calibration algorithms

• MWR L1/L2 simulation– Deliver forward radiation transfer model

– Deliver V-0 wind speed retrieval ATBD

– Deliver V-0 rain rate retrieval ATBD

• Develop preliminary AQ roughness correction algorithm