Improving sea ice type discrimination by the simultaneous use of SSM/I and scatterometer data

The multi-year sea ice (MY) concentration as determined with the NASA Team algorithm (NTA) shows an increase during winter. This unrealistic feature can be reduced using combined active and passive remote sensing data, leading to a more realistic estimation of MY area. Our joint analysis of SSM/I, QuikSCATterometer (QSCAT) and meteorological data reveals events (i.e. intervals in space and time) where increased surface roughness and volume scattering, after a melt–refreezing episode, alters the passive microwave signature of the undisturbed sea ice surface. In these events, the calculation of MY and FY areas employing the NTA leads to false estimations of their amounts. It is shown that when such events occur, QSCAT backscatter values increase by more than 3 dB. This backscatter variation can be easily detected and the FY and MY area determination of the NTA can be corrected accordingly within defined event–regions. Using this method, called Simultaneous NTA, we found that in May 2000 12 % of the area detected by the NTA as MY has to be corrected to FY. As a consequence, a detailed reanalysis of the 20-year passive microwave data set is suggested to more precisely compute the MY area.

[1]  Thomas V. Martin,et al.  Large‐scale drift of Arctic Sea ice retrieved from passive microwave satellite data , 2000 .

[2]  W. Oechel,et al.  Observational Evidence of Recent Change in the Northern High-Latitude Environment , 2000 .

[3]  Donald J. Cavalieri,et al.  Arctic and Antarctic Sea Ice, 1978-1987: Satellite Passive-Microwave Observations and Analysis , 1992 .

[4]  Robert Ezraty,et al.  Intercomparison of backscatter maps over Arctic sea ice from NSCAT and the ERS scatterometer , 1999 .

[5]  Donald J. Cavalieri,et al.  Arctic sea ice extents, areas, and trends, 1978-1996 , 1999 .

[6]  Christian Haas,et al.  The seasonal cycle of ERS scatterometer signatures over perennial Antarctic sea ice and associated surface ice properties and processes , 2001, Annals of Glaciology.

[7]  James P. Hollinger,et al.  SSM/I instrument evaluation , 1990 .

[8]  J. Curry,et al.  Observation and Interpretation of Microwave Cloud Signatures over the Arctic Ocean during Winter , 2003 .

[9]  Donald J. Cavalieri,et al.  Spatial distribution of trends and seasonally in the hemispheric sea ice covers: 1978–1996 , 1999 .

[10]  Shalina,et al.  Satellite Evidence for an Arctic Sea Ice Cover in Transformation. , 1999, Science.

[11]  F. Gohin,et al.  A first try at identification of sea ice using the three beam scatterometer of ERS-1 , 1994 .

[12]  Tamara Shapiro Ledley,et al.  Snow on sea ice: Competing effects in shaping climate , 1991 .

[13]  Ian Allison,et al.  Snow on Antarctic sea ice , 2001 .

[14]  Arctic sea ice microwave signatures. A Lagrangian approach during the NSCAT mission , 1999, IEEE 1999 International Geoscience and Remote Sensing Symposium. IGARSS'99 (Cat. No.99CH36293).

[15]  Douglas M. Smith,et al.  Observation of perennial Arctic sea ice melt and freeze-up using passive microwave data , 1998 .

[16]  R. Kwok,et al.  Seasonal Characteristics of the Perennial Ice Cover of the Beaufort Sea , 1996 .

[17]  C. C. Wackerman,et al.  Aircraft active and passive microwave validation of sea ice concentration from the Defense Meteorological Satellite Program special sensor microwave imager , 1991 .

[18]  Mark Drinkwater,et al.  Recent changes in the microwave scattering properties of the Antarctic ice sheet , 2000, IEEE Trans. Geosci. Remote. Sens..

[19]  Donald J. Cavalieri,et al.  Satellite passive microwave observations and analysis of Arctic and Antarctic sea ice, 1978–1987 , 1993, Annals of Glaciology.

[20]  Ron Kwok,et al.  Area balance of the Arctic Ocean perennial ice zone : October 1996 to April 1997 , 1999 .