Aquarius Algorithm Workshop 18-20 March 2007 College of Engineering Department of Atmospheric,...
-
Upload
branden-elliott -
Category
Documents
-
view
213 -
download
0
Transcript of Aquarius Algorithm Workshop 18-20 March 2007 College of Engineering Department of Atmospheric,...
![Page 1: Aquarius Algorithm Workshop 18-20 March 2007 College of Engineering Department of Atmospheric, Oceanic & Space Sciences Chris Ruf Space Physics Research.](https://reader035.fdocuments.us/reader035/viewer/2022062806/56649eb35503460f94bba803/html5/thumbnails/1.jpg)
Aquarius Algorithm Workshop 18-20 March 2007
College of Engineering Department of Atmospheric, Oceanic & Space Sciences
Chris RufSpace Physics Research Laboratory
Dept. of Atmospheric, Oceanic & Space SciencesUniversity of Michigan
[email protected], 734-764-6561 (V), 734-936-0503 (F)
Antenna Sidelobe Correction for Land Contamination
![Page 2: Aquarius Algorithm Workshop 18-20 March 2007 College of Engineering Department of Atmospheric, Oceanic & Space Sciences Chris Ruf Space Physics Research.](https://reader035.fdocuments.us/reader035/viewer/2022062806/56649eb35503460f94bba803/html5/thumbnails/2.jpg)
19 Mar 2008 Ruf, Land Contamination, Aquarius Algo Workshop pg 2 of 10
Contributions to Antenna Temperature
TB(Earth in Mainlobe)TB (Earth in Sidelobes) ~ 150K
s2
s1
Parabolic Reflector
Feedhorns
TB(Earth in Mainlobe)TB (Earth in Sidelobes) ~ 150K
s2
s1
Parabolic Reflector
Feedhorns
TB(Earth in Mainlobe)TB (Earth in Sidelobes) ~ 150K
s2
s1
Parabolic Reflector
Feedhorns
])1([
)1(1
cearthSLMBearthSLearthSLAB
cearthSLMBearthSLearthSLMBBA
TTTT
TTTT
MB
![Page 3: Aquarius Algorithm Workshop 18-20 March 2007 College of Engineering Department of Atmospheric, Oceanic & Space Sciences Chris Ruf Space Physics Research.](https://reader035.fdocuments.us/reader035/viewer/2022062806/56649eb35503460f94bba803/html5/thumbnails/3.jpg)
19 Mar 2008 Ruf, Land Contamination, Aquarius Algo Workshop pg 3 of 10
General Description of Algorithm
• Model TB entering antenna from Earth at all view angels– Derive model from satellite radiometer observations
– Stratify by lat/lon of antenna, obs. frequency, time of year
• Derive sidelobe contribution to TA as antenna pattern weighted average
• Incorporate improved knowledge of sidelobe contribution into standard APC algorithm
![Page 4: Aquarius Algorithm Workshop 18-20 March 2007 College of Engineering Department of Atmospheric, Oceanic & Space Sciences Chris Ruf Space Physics Research.](https://reader035.fdocuments.us/reader035/viewer/2022062806/56649eb35503460f94bba803/html5/thumbnails/4.jpg)
19 Mar 2008 Ruf, Land Contamination, Aquarius Algo Workshop pg 4 of 10
Heritage with Other Flight Projects• Obligis, E., L. Eymard and N. Tran, “A new sidelobe
correction algorithm for microwave radiometers: Application to the Envisat instrument,” IEEE Trans. Geosci. Remote Sens., 45(3), 2007.– Use 1 year of Envisat nadir TBs at 23.8 and 36.5 GHz– Stratify by season – 4 time bins– Use nadir TBs directly in antenna pattern weighted averages– Incorporated into Envisat Level 1B operational processing in Nov.
2005• Developed with Jason Microwave Radiometer; Planned for
AMR on OSTM (Jason-2); Shannon Brown lead– Use 3 year JMR nadir TBs at 18.7, 23.8 and 34.0 GHz– Derive model to estimate off-nadir TB from nadir obs by regression of
simulated database of TBs at many angles from ocean/atmos data record and radiative transfer model (over ocean only)
22110 ),0(),(),0(),(),(),( fTfcfTfcfcfT BincBincincinc
SLB
oo
![Page 5: Aquarius Algorithm Workshop 18-20 March 2007 College of Engineering Department of Atmospheric, Oceanic & Space Sciences Chris Ruf Space Physics Research.](https://reader035.fdocuments.us/reader035/viewer/2022062806/56649eb35503460f94bba803/html5/thumbnails/5.jpg)
19 Mar 2008 Ruf, Land Contamination, Aquarius Algo Workshop pg 5 of 10
Brown JMR Results (1 of 3)(ref. Brown, S., “Generate JMR TE Maps,” JPL Tech. Memo, 4 Apr 2006)
Map of the 18.7 GHz nadir brightness temperature centered at LAT=35.5oE, LON=17oN. Inner black circle represents 10o off-nadir. Outer black circle is the Earth limb at 1338 km altitude, approximately 55o off-nadir.
![Page 6: Aquarius Algorithm Workshop 18-20 March 2007 College of Engineering Department of Atmospheric, Oceanic & Space Sciences Chris Ruf Space Physics Research.](https://reader035.fdocuments.us/reader035/viewer/2022062806/56649eb35503460f94bba803/html5/thumbnails/6.jpg)
19 Mar 2008 Ruf, Land Contamination, Aquarius Algo Workshop pg 6 of 10
Brown JMR Results (2 of 3)(ref. Brown, S., “Generate JMR TE Maps,” JPL Tech. Memo, 4 Apr 2006)
Earth incidence angle from perspective of 1338 km altitude above ground at LAT=35.5oE, LON=17oN.
![Page 7: Aquarius Algorithm Workshop 18-20 March 2007 College of Engineering Department of Atmospheric, Oceanic & Space Sciences Chris Ruf Space Physics Research.](https://reader035.fdocuments.us/reader035/viewer/2022062806/56649eb35503460f94bba803/html5/thumbnails/7.jpg)
19 Mar 2008 Ruf, Land Contamination, Aquarius Algo Workshop pg 7 of 10
Brown JMR Results (3 of 3)(ref. Brown, S., “Generate JMR TE Maps,” JPL Tech. Memo, 4 Apr 2006)
(LEFT) Nadir TB observations at 18.7 GHz(RIGHT) Modeled upwelling TB from perspective of 1338 km altitude above ground at
LAT=35.5oE, LON=17oN. (Note: no change from nadir for land TBs)
![Page 8: Aquarius Algorithm Workshop 18-20 March 2007 College of Engineering Department of Atmospheric, Oceanic & Space Sciences Chris Ruf Space Physics Research.](https://reader035.fdocuments.us/reader035/viewer/2022062806/56649eb35503460f94bba803/html5/thumbnails/8.jpg)
19 Mar 2008 Ruf, Land Contamination, Aquarius Algo Workshop pg 8 of 10
Aquarius Sidelobe Land Contribution (1 of 2)(ref. Brown, S., “Aquarius APC,” JPL Aquarius TIM, 1 Feb 2006,)
• Aquarius required to retrieve salinity > 450 km from coast
All points in blue > 450 km from land
![Page 9: Aquarius Algorithm Workshop 18-20 March 2007 College of Engineering Department of Atmospheric, Oceanic & Space Sciences Chris Ruf Space Physics Research.](https://reader035.fdocuments.us/reader035/viewer/2022062806/56649eb35503460f94bba803/html5/thumbnails/9.jpg)
19 Mar 2008 Ruf, Land Contamination, Aquarius Algo Workshop pg 9 of 10
Aquarius Sidelobe Land Contribution (2 of 2)(ref. Brown, S., “Aquarius APC,” JPL Aquarius TIM, 1 Feb 2006,)
• Less than 10% of on-Earth sidelobe fraction on land at 450 km (p1V)
(Assumes knowledge of TLand is better than 15 K)
![Page 10: Aquarius Algorithm Workshop 18-20 March 2007 College of Engineering Department of Atmospheric, Oceanic & Space Sciences Chris Ruf Space Physics Research.](https://reader035.fdocuments.us/reader035/viewer/2022062806/56649eb35503460f94bba803/html5/thumbnails/10.jpg)
19 Mar 2008 Ruf, Land Contamination, Aquarius Algo Workshop pg 10 of 10
Aquarius Implementation
• Use SMOS observations to train Tearth model– Model for incidence angle dependence of TB over ocean
and land can be better constrained by obs
• Pre-launch simulations– Build Tearth database
– Assess sensitivity of correction to errors in • Integrated antenna beam fractions
• Tearth (seasonal dependence, RFI effects, other?)