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| Titel |
Estimating ice phenology on large northern lakes from AMSR-E: algorithm development and application to Great Bear Lake and Great Slave Lake, Canada |
| VerfasserIn |
K.-K. Kang, C. R. Duguay, S. E. L. Howell |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 6, no. 2 ; Nr. 6, no. 2 (2012-03-08), S.235-254 |
| Datensatznummer |
250003475
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| Publikation (Nr.) |
 copernicus.org/tc-6-235-2012.pdf |
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| Zusammenfassung |
| Time series of brightness temperatures (TB) from the Advanced Microwave
Scanning Radiometer–Earth Observing System (AMSR-E) are examined to
determine ice phenology variables on the two largest lakes of northern
Canada: Great Bear Lake (GBL) and Great Slave Lake (GSL). TB
measurements from the 18.7, 23.8, 36.5, and 89.0 GHz channels (H- and V-
polarization) are compared to assess their potential for detecting
freeze-onset/melt-onset and ice-on/ice-off dates on both lakes. The 18.7 GHz
(H-pol) channel is found to be the most suitable for estimating these ice
dates as well as the duration of the ice cover and ice-free seasons. A new
algorithm is proposed using this channel and applied to map all ice
phenology variables on GBL and GSL over seven ice seasons (2002–2009).
Analysis of the spatio-temporal patterns of each variable at the pixel level
reveals that: (1) both freeze-onset and ice-on dates occur on average about
one week earlier on GBL than on GSL (Day of Year (DY) 318 and 333 for GBL;
DY 328 and 343 for GSL); (2) the freeze-up process or freeze duration
(freeze-onset to ice-on) takes a slightly longer amount of time on GBL than
on GSL (about 1 week on average); (3) melt-onset and ice-off dates occur on
average one week and approximately four weeks later, respectively, on GBL
(DY 143 and 183 for GBL; DY 135 and 157 for GSL); (4) the break-up process or
melt duration (melt-onset to ice-off) lasts on average about three weeks
longer on GBL; and (5) ice cover duration estimated from each individual
pixel is on average about three weeks longer on GBL compared to its more
southern counterpart, GSL. A comparison of dates for several ice phenology
variables derived from other satellite remote sensing products (e.g. NOAA
Interactive Multisensor Snow and Ice Mapping System (IMS), QuikSCAT, and
Canadian Ice Service Database) show that, despite its relatively coarse
spatial resolution, AMSR-E 18.7 GHz provides a viable means for monitoring
of ice phenology on large northern lakes. |
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