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ANALYSIS OF SURFACE MELTING AND SNOW ACCUMULATION OVER THE GREENLAND ICE SHEET FROM SPACEBORNE MICROWAVE SENSORS

Bhattacharya, Indrajit
http://rave.ohiolink.edu/etdc/view?acc_num=osu1276621670

Abstract Details

2010, Doctor of Philosophy, Ohio State University, Geological Sciences.
Continuous monitoring of changes in the Greenland ice sheet from both space and air borne sensors has been conducted since the early 1970’s. Since the mid-1990’s dramatic changes occurring on the Greenland ice sheet have been observed both from space borne sensors and field work. These changes, primarily mass loss from the ice sheet, are related to the observed trend of earth’s warmer climate in recent decades both in peer reviewed journals and in popular media. This dissertation addresses two parameters that contribute to Greenland ice sheet mass balance estimates. The first factor is characterization of surface melting of the Greenland ice sheet from satellite-based passive and active microwave sensors. We use a wavelet based edge detection technique to delineate surface melt from brightness temperature measured by passive microwave sensors. Along with brightness temperature data, we also use normalized backscatter data from the Quick Scatterometer (QuikSCAT) as an independent sensor for comparison with the radiometer derived results. We use a semi-empirical threshold based method for surface melt detection from QuikSCAT. Our results show a step-like, consistent increase in melt area of the Greenland ice sheet since 1995. This step-like increase is also observed in the mean summer air temperature along portions of the Greenland coast. The 1995 step-like increase of melt area (and melt index, a measure of melt intensity) is correlated with a distinct change of the North Atlantic Oscillation (NAO) index (from positive to negative) after 1995. The second factor is mass accumulation in the upper reaches of the ice-sheet. We use an empirical model that correlates mean annual brightness temperature to annual accumulation rate. We apply a microwave emission model for the dry snow region of Greenland to show that 37 GHz vertically polarized brightness temperature data are better suited to capture the inter-annual variability of snow accumulation. Using our model we estimate a snow accumulation time series from brightness temperature for 150 km x 150 km area around Summit Camp in central Greenland. Using measured surface velocities and ice thickness we calculate the surface mass balance for our study area. We find a positive mass balance of 3.18 ± 6.0 cm/yr. Our mass balance derived elevation change is in agreement with satellite altimeter data and published results of other researchers.
Kenneth Jezek (Advisor)
Joel Johnson (Committee Member)
Ralph von Frese (Committee Member)
182 p.
Geophysics
Cryosphere; Passive Microwave; Scatterometer; Greenland; Melting; Snow Accumulation; Radiative Transfer

Recommended Citations

Citations

  • Bhattacharya, I. (2010). ANALYSIS OF SURFACE MELTING AND SNOW ACCUMULATION OVER THE GREENLAND ICE SHEET FROM SPACEBORNE MICROWAVE SENSORS [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1276621670

    APA Style (7th edition)

  • Bhattacharya, Indrajit. ANALYSIS OF SURFACE MELTING AND SNOW ACCUMULATION OVER THE GREENLAND ICE SHEET FROM SPACEBORNE MICROWAVE SENSORS. 2010. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1276621670.

    MLA Style (8th edition)

  • Bhattacharya, Indrajit. "ANALYSIS OF SURFACE MELTING AND SNOW ACCUMULATION OVER THE GREENLAND ICE SHEET FROM SPACEBORNE MICROWAVE SENSORS." Doctoral dissertation, Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1276621670

    Chicago Manual of Style (17th edition)

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This open access ETD is published by The Ohio State University and OhioLINK.