Hydrologic Outlets of the Greenland Ice Sheet, Version 1

The Hydrologic Outlets of the Greenland Ice Sheet data set contains GIS point shapefiles that include 891 observed and potential hydrologic outlets of the Greenland Ice Sheet, as identified by Lewis and Smith (2009), using satellite imagery. There are 460 observed hydrologic outlets that include proglacial streams and rivers emerging from the ice sheet (length scale >1 km), proglacial lakes touching the ice edge or clearly connected to it via streams or rivers (length scale >3 km), and sediment-rich plumes exiting tidewater glaciers into fjords. Also, there are 431 potential hydrologic outlets that include point locations with release of meltwater from fjords without obvious sediment discharge, as well as locations where the ice sheet directly connects to the ocean that cannot be proven to release meltwater.

Meltwater features along the entire edge of the ice sheet were mapped via photo interpretation of GoogleEarth and Landsat ETM+ 15 m panchromatic data. The exact acquisition dates of the imagery are not available; however, owing to the light and relatively snow-free conditions seen in the GoogleEarth and Landsat images, it is presumed that they were taken during the summer season. Neither Landsat or GoogleEarth images were available for a section of ice sheet within the northern Tunu region; therefore, that region was excluded from the study. This excluded area represents approximately 0.9 percent of the ice sheet perimeter. Data are available via FTP, and can be read in any GIS software. The following journal article provides documentation for this data set: Lewis, Sarah and Laurence Smith. 2009. Hydrologic Drainage of the Greenland Ice Sheet. Hydrological Processes doi: 10.1002/hyp.7343. This journal article can be accessed from the Documentation link at the top of this Web page.

格陵兰冰盖水文出口数据集（Hydrologic Outlets of the Greenland Ice Sheet）收录了Lewis与Smith（2009年）通过卫星影像识别出的891个格陵兰冰盖观测与潜在水文出口，数据格式为地理信息系统（Geographic Information System, GIS）点形状文件（shapefile）。其中包含460个已观测到的水文出口，具体包括：从冰盖流出的冰前溪流与河流（长度＞1km）、接触冰缘或通过溪流/河流与冰缘明确相连的冰前湖泊（长度＞3km），以及从潮汐冰川排入峡湾的富沉积物羽流。另有431个潜在水文出口，包括峡湾排出融水但无明显沉积物排放的点位，以及冰盖直接与海洋相连但无法证实有融水排出的点位。
冰盖全域边缘的融水特征通过谷歌地球（GoogleEarth）与陆地卫星ETM+（Landsat ETM+）15米全色影像的目视解译完成绘制。影像的精确获取日期未留存，但鉴于谷歌地球与陆地卫星影像中光照良好且积雪相对较少，推测其拍摄于夏季。北图努（Tunu）区域的部分冰盖无法获取陆地卫星或谷歌地球影像，因此该区域被排除在本研究之外，其覆盖范围约占冰盖总周长的0.9%。该数据集可通过文件传输协议（File Transfer Protocol, FTP）获取，且可在任意地理信息系统软件中读取。本数据集的相关文档可参考以下期刊论文：Lewis, Sarah与Laurence Smith，2009年，《格陵兰冰盖水文排水》（Hydrologic Drainage of the Greenland Ice Sheet），刊载于《水文过程》（Hydrological Processes），DOI：10.1002/hyp.7343。该论文可通过本网页顶部的“文档”链接获取。