A Comparison of Passive Microwave Derive Melt Extent to Melt Intensity Estimated from Combined Optical and Thermal Satellite Signatures Over the Greenland Ice Sheet from Unquiea Wade Mentor: Dr. Derrick Lampkin

The Center for Remote Sensing of Ice Sheets The Center for Remote Sensing of Ice Sheets (CReSIS) is a Science and Technology Center established by the National Science Foundation (NSF) in 2005 The mission of CReSIS is to develop new technologies and computer models to measure and predict the response of sea level change to the mass balance of ice sheets in Greenland and Antarctica. NSF’s Science and Technology Center (STC) program combines the efforts of scientists and engineers to respond to problems of global significance, supporting the intense, sustained, collaborative work that is required to achieve progress in these areas.

The earth is a system Which is effected by processes that occur Responds to these processes and changes These changes are then study and monitored

Data  Special Sensor Microwave/ Imager brightness temperature grids were downloaded from National Snow and Ice Data Center. (NDIDC)  SSMI files were collected for three different channels  Satellite Ascending/Descending: 19H.GHZ,37V.GHZ, /37V.GHZ

Brightness Temperature This distinct change is observed in the brightness temperature (Tb) signal according to the Rayleigh Jeans approximation: where Tb refers to the microwave brightness temperature at a particular wavelength (λ or frequency υ ), ε is the microwave emissivity, and Tp is the effective physical temperature of the snow (Zwally, 1977)

Melt Occurrence and Extent Retrival Techniques  Technique 1:Cross Polarization Gradient Ratio (XPGR ) [Abdalati and Steffen [1995, 1997]  Technique 2: Dirnual Ampltiude Variation (DAV) [Ramage and Isacks [2002]

XPGR Derived Melt Occurrence (Day 161, Year 2000) Blue: Melt Occurrence White: No Melt Occurrence

DAV Derived Melt Occurrence (Day 161, Year 2000) Blue: Melt Occurrence White: No Melt Occurrence

Melt Magnitude Retrieval Liquid Water Fraction

Results

Results Contd..

Results Contd…

Conclusions  Results indicate that DAV show a much more proportional relationship to melt magnitude than XPGR consistently during the analysis period. Both techniques show a scaled increase in melt occurrence with melt magnitude from the early part of the melt season (Day 145- May 25) than later in the melt season (Day 193-July 12).  Difference in the comparison of XPGR and DAV to E-melt may be due to the ability of DAV to track more night time persistent melt, producing higher occurrences of melt. E- melt values derived from surface reflectance and temperature may be sensitive the diurnal effects as well resulting in a stronger relationship to DAV than XPGR. Further work is necessary to explain these trends.

Questions

Acknowledgements  Center for Remote Sensing of Ice Sheets  Center of Excellence in Remote Sensing Education and Research  College of Earth and Mineral Sciences  Peter Burkett  Dr. Derrick Lampkin  Dr. Linda Hayden