[ACG38-P20] Overflow of a proglacial stream in Qaanaaq, northwestern Greenland
Keywords:Greenland, Glacier, Surface mass balance, Freshwater runoff
The overflow on 21 July 2015 resulted from a combination of the substantial amount of meltwater runoff from Qaanaaq Glacier and the lack of snowpack in the upper part of the glacier. The second highest air temperature in 2015 was observed at Qaanaaq Airport and there was no rainfall on that day. At the upper part of the glacier, the forth greatest amount of melting in 2013–2017 was calculated on that day by NHM-SMAP. In 2015, snow depth at 944 m a.s.l. of the glacier on 21 July was the lowest in 2013–2017. The lack of snowpack in the upper part was a likely reason of the greater amount of discharge because less amount of meltwater was absorbed by snowpack. The third greatest daily peak discharge of the proglacial stream in 2015 was simulated for 21 July, which was 18,071 m3 h−1. The overflow on 2 August 2016 resulted from substantial amount of rainfall. Daily precipitation of 89.6 mm with hourly maximum of 23.4 mm was recorded at the village on that day. This hourly rainfall was the greatest since the observation started from June 2014. The rainfall probably covered a large part of the glacier because NHM-SMAP computed the largest daily rainfall at the upper part in 2016 on that day. The greatest daily peak discharge in 2016 was simulated for 2 August, which was 18,146 m3 h−1.
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