Spatial distribution of cryoconite granules and microorganisms on Qaanaaq Glacier, Greenland

第6回極域科学シンポジウム分野横断セッション：[IB2] 地球環境変動の解析と地球生命システム学の構築11月19日（木）　統計数理研究所 セミナー室1（D305

Microbial composition changes in cryoconite formation process in Northwestern Greenland

第3回極域科学シンポジウム/特別セッション「これからの北極研究」11月28日（水） 国立極地研究所 2階大会議

Spectral albedos measured on Qaanaaq Glacier in Greenland

第2回極域科学シンポジウム/第34回気水圏シンポジウム 11月15日（火） 統計数理研究所 セミナー室

Project in Greenland in 2011-2013（2011-2013年グリーンランドにおけるSIGMAプロジェクトの野外活動報告）

Field activities of the “Snow Impurity and Glacial Microbe effects on abrupt warming in the Arctic” (SIGMA) Project in Greenland in the summer season of 2011-2013 are reported;this consists of (1) glaciological and meteorological observations and (2) biological observations.　In 2011, we conducted a field reconnaissance in the Qaanaaq, Ilulissat and Kangerlussuaq areas to enable continuous meteorological observations with automatic weather stations (AWS), campaign observations for glaciology, meteorology and Biology and shallow ice core drilling, which were planned for 2012-2014.　Based on the results, we chose the Qaanaaq area in northwest Greenland as our main activity area and the Kangerlussuaq area in mid-west Greenland partly for biological observations.　In 2012, we conducted field observations for (1) and (2) mentioned above together with installations of two AWSs at site SIGMA-A on The Greenland ice sheet (GrIS) and at site SIGMA-B on the Qaanaaq ice cap (QIC) from June to August.　Surface snow and ice over all of the QIC melted in July and August 2012, and most of the Glacier surface appeared to be dark-colored, probably due to mineral dust and glacial microbial products.　In 2013, we carried out similar observations in the Qaanaaq area.　However, the weather and Glacier surface conditions were considerably different from those in 2012.　Snow cover over the summer of 2013 remained over large areas with elevations higher than about 700 m on QIC.　Biological activity on the Glacier surface appears to be substantially lower as compared to that in 2012

2011年及び2012年に北西グリーンランド氷床上で観測された光吸収性積雪不純物濃度

Light-absorbing snow impurities of elemental carbon (EC), organic carbon (OC), and mineral dust have been measured at three locations at elevations from 1,469 to 1,992 m on August 1, 2011, and at the site SIGMA-A (78°N, 68°W, elevation 1,490 m) on the northwest Greenland ice sheet (GrIS) during the period from June 28 to July 12, 2012.　At SIGMA-A, a remarkable snow surface lowering together with snow melting was observed during the observation period in 2012, when a record surface melting event occurred over the GrIS. The concentrations in the surface were 0.9, 3.8, and 107 ppbw for EC, OC, and dust, respectively, at the beginning of the period, which increased to 4.9, 17.2, and 1327 ppbw for EC, OC, and dust, respectively, at the end.　The EC and dust concentrations were remarkably higher than those at the three locations in 2011 and the recent measurements at Summit.　However, our measurements for EC and OC could be underestimated because a recent study indicates that the collection efficiency of a quartz fiber filter, which we employed, is low.　We confirm that the snow surface impurity concentrations were enhanced in the observation period, which can be explained by the effects of sublimation/evaporation and snow melt amplification associated with drastic melting.　Scanning electron microscopy analysis of surface snow impurities on July 12 revealed that the major component of snow impurities is mineral dust with size larger than 5 μm, which suggests possible emission source areas are peripheral bare soil regions of Greenland and/or the Canadian Arctic