TY - JOUR
T1 - Mapping of seasonal freeze-thaw transitions across the pan-Arctic land and sea ice domains with satellite radar
AU - Mortin, J.
AU - Schroder, T.M.
AU - Hansen, Aksel Walløe
AU - Holt, B.
AU - McDonald, K.C.
PY - 2012/8/3
Y1 - 2012/8/3
N2 - To monitor the pan-Arctic seasonal freeze-thaw transitions of the land surface and sea ice, we analyze daily backscatter data from satellite scatterometry to examine the time series on an annual basis by applying an optimal edge detection scheme, and iterate against an internal median climatology to mitigate unreasonable outliers. By applying this novel algorithm to resolution-enhanced QuikSCAT data from 1999 to 2009, we have mapped a decade of seasonal freeze-thaw transitions across the landmass and sea ice north of 60N at a spatial resolution better than 5km. The data set has been validated against surface air temperature measurements and snow depth obtained from a distributed network of weather stations and drift buoys. Most retrieved timings from surface and QuikSCAT measurements agree to less than a week at thaw transition for both land and sea ice and at freeze transition for sea ice, indicating successful retrieval over a range of surface covers. While the spatial pattern of freeze-thaw transition changes substantially from year to year, the interannual variability of the mean transition timing over a particular surface is small.
AB - To monitor the pan-Arctic seasonal freeze-thaw transitions of the land surface and sea ice, we analyze daily backscatter data from satellite scatterometry to examine the time series on an annual basis by applying an optimal edge detection scheme, and iterate against an internal median climatology to mitigate unreasonable outliers. By applying this novel algorithm to resolution-enhanced QuikSCAT data from 1999 to 2009, we have mapped a decade of seasonal freeze-thaw transitions across the landmass and sea ice north of 60N at a spatial resolution better than 5km. The data set has been validated against surface air temperature measurements and snow depth obtained from a distributed network of weather stations and drift buoys. Most retrieved timings from surface and QuikSCAT measurements agree to less than a week at thaw transition for both land and sea ice and at freeze transition for sea ice, indicating successful retrieval over a range of surface covers. While the spatial pattern of freeze-thaw transition changes substantially from year to year, the interannual variability of the mean transition timing over a particular surface is small.
U2 - 10.1029/2012jc008001
DO - 10.1029/2012jc008001
M3 - Journal article
SN - 0148-0227
VL - 117
SP - C08004
JO - Journal of Geophysical Research
JF - Journal of Geophysical Research
ER -