IAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring", Hyderabad, India,2002 
  
It is observed that MSMR derived SIC values over region of 
thick, multiyear ice in the Weddell and Ross Sea Sectors are 
relatively lower. This could be attributed to the use of 10 GHz 
in case of MSMR compared to 37 GHz of SSM/I. This needs 
further investigation. 
5.0 CONCLUDING REMARKS 
Passive microwave radiometers operating on space platforms 
are difficult to calibrate n an absolute sense. There have been 
many different approaches for this. Inter-calibrations between 
SMMR and SSM/I and between successive SSM/Is have been 
attempted in the past. As more and more sophisticated PMRs 
are being launched, internationally there are ongoing efforts to 
improve the calibration procedures (Bhandari et al, 2002, 
Desnos, 2002). 
In this paper, we have concentrated on the relative calibration 
of MSMR onboard OCEANSAT-1 using independent SSM/I 
measurements collected simultaneously over the Antarctic 
region. The inter-comparison between MSMR and SSM/I data 
at the brightness temperature level as well as at the derived 
product level attempted above gives us confidence in the use 
of MSMR data for deriving various characteristics of sea ice 
over the Antarctic and Arctic regions. Independent 
information from MSMR can be used synergistically with 
SSM/I and recently launched AMSR-E onboard AQUA 
satellite to gain insight into the variability of sea ice in the 
polar regions and to understand their role in the Earth’s 
climate. 
Acknowledgements 
The authors wish to acknowledge the encouragement and 
support to Antarctic Remote Sensing program by Director, 
SAC and Group Director MOG/SAC. The authors are grateful 
to Dr. Joey Comiso of NASA/GSFC for making available 
SSM/I data used in the above study and for fruitful 
interaction. The above studies have benefited from 
discussions with scientific colleagues at SAC and NCAOR. 
References: 
Ali, M.M., and co-authors, 2000. Validation of Multi 
frequency scanning microwave radiometer geophysical 
parameter data products. Proc. of 5^ PORSEC, Goa, India , 
1, pp. 182-191. 
Bhandari, S.M., Dash MK, Vyas, N.K., Khare, N. and 
Pandey, P.C., 2002. Microwave Remote Sensing of Ice in the 
Antarctic Region, Advances in Marine and Antarctic Science 
(Eds. D. Sahoo and P.C. Pandey), APH Pub. Corp., New 
Delhi , pp. 423-441. 
Cavalieri, D.J., Gloersen, P. and Campbell W.J., 1984. 
Determination of sea ice parameters with the Nimbus-7 
SMMR. JI. Geophys. Res., 89, pp. 5355-5369. 
Desnos, Yves-Louis, 2002. The Working Group on 
Calibration and Validation. CEOS Newsletter # 19, pp. 5. 
413 
Comiso, J.C. , 2000. Variability and trends in Antarctic 
Surface Temperature from in-situ and Satellite Infrared 
measurements. Jl. Climate, 13, pp. 1674-1696. 
Cavalieri DJ, Parkinson C.L. and 
Passive Microwave algorithms for sea 
Rem. 
Comiso, J.C, 
Gloersen,P., 1997. 
ice concentration: a comparison of two techniques. 
Sen. Env., 60, pp. 357-384. 
Dash M.K., Bhandari S.M., Vyas N.K., Khare N.K., Mitra 
A..and Pandey P.C., 2001. Oceansat-MSMR imaging of 
the Antarctic and the Southern Polar Ocean. Int. Jl. Rem. 
Sen. 22, pp. 3253-3259. 
Gloersen, P., Campbell W.J., Cavalieri, D.J., Comiso J.C., 
Parkinson C.L. and Zwally HJ, 1992. Arctic and 
Antarctic Sea Ice: 1978-1987: Satellite Passive Microwave 
Observations and Analysis. NASA SP-511, pp. 290. 
Derivation and 
Int. JL 
Hanna, E. and Bamber, J, . 2001. 
optimization of a new Antarctic Sea Ice record. 
Rem. Sen. 22, pp. 113-139. 
Johannessen O.M., Lisaeter K.A., Drange H., and Evensen 
G., 2000. Two decades of microwave satellite observation 
of Arctic Sea Ice Variability and Trends. Proc. of sh 
PORSEC, Goa, India 2, pp. 722-726. 
King, J.C., and Turner, J., 1997. Antarctic Meteorology 
and Climatology. Cambridge Univ. Press, Cambridge, UK 
Massom, R., 1991. Satellite Remote Sensing of Polar 
Regions. Lewish Publishers, FL, USA 
Parkinson, C.L., Cavalieri, D.J., Gloersen, P., Zwally, H.J. 
and Comiso J.C., 1999. Arctic sea ice extents, areas and 
trends. Jl. Geophys. Res. 104 (C9), pp. 20837-20,856. 
Ulaby, F., Moore, R. and Fung. A, 1982. Microwave 
Remote Sensing — Vol. 1 — Fundamentals and Radiometry. 
Addison-Wesley, MA, USA 
USGCRP : “Our Changing Planet” 2001. The FY 2001 
U.S. Global Change Research Program 
Vyas N.K., Dash M.K., Bhandari S.M., Khare N.K., Mitra 
A. and Pandey P.C., 2001. Large Scale Antarctic Features 
captured by  Multi-frequency Scanning — Microwave 
Radiometer onboard OCEANSAT-1. Current Science 80, 
pp. 1319-1322. 
Vyas N.K., Dash M.K., Bhandari S.M., Khare N.K., Mitra 
A. and Pandey P.C., 2002. On the secular trends in the Sea 
Ice Extent over the Antarctic region based on OCEANSAT- 
1 MSMR Observations. Int. Jl. Rem. Sen. under 
publication 
Zwally, H.J., 1984. Passive Microwave Remote Sensing for 
Sea Ice Research. NASA HQ Report