MODIS-Derived Arctic Melt Season Fog and Low Stratus over East Greenland Glaciers and the Ice Sheet
MODIS-Derived Arctic Melt Season Fog and Low Stratus over East Greenland Glaciers and the Ice Sheet
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DOI：
10.1080/07038992.2019.1635878
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发表时间：
2019-07
影响因子：
2.6
通讯作者：
H. Jiskoot;Theo Harvey;Tyrell R. Nielsen
中科院分区：
文献类型：
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作者：
H. Jiskoot;Theo Harvey;Tyrell R. Nielsen
翻译后摘要在第一次尝试量化雾在巨大的冰雪表面，我们提出了显著的融化季节雾事件在东格陵兰冰川和格陵兰冰盖的水平和垂直空间范围。两个已建立的MODIS雾分类方法进行了调整，用于在北极冰川化地区，并适用于Terra-MODIS收集6 1B级场景和2级云产品。在6个步骤中，我们将这些产品与数字高程模型和冰川范围结合起来处理，以将雾与冰川上空的低层云分开。该程序使用Landsat 7和地面观测进行了优化，并与并发CloudSat-CALIPSO非常低级别的云进行了验证。MODIS衍生的最终产品是东格陵兰上空500米分辨率的雾和低层云掩模图，并附有雾的统计数据。2002-2007年融化季节的六天被绘制出来，揭示了7月至8月的最大雾范围，覆盖了20，000 - 70，000平方公里的冰川表面。雾的平均厚度为200米，最大内陆范围的连续雾约100公里，尽管斑块出现在冰盖的高处。我们的方法和结果将有助于云变化检测和云辐射强迫和热效应的量化在雪和冰表面。
Abstract In a first attempt to quantify fog over vast snow and ice surfaces, we present the horizontal and vertical spatial extent of significant melt-season fog events over East Greenland glaciers and the Greenland ice sheet. Two established MODIS fog classification methods are adjusted for use in Arctic glacierized regions and applied to Terra-MODIS Collection 6 Level 1B scenes and Level 2 cloud products. In a 6-step procedure, we process these products in combination with a digital elevation model and glacier extents to separate fog from low stratus over glaciers. The procedure was optimized using Landsat 7 and ground observations and verified with concurrent CloudSat–CALIPSO very low-level clouds. The MODIS-derived end products are 500-m resolution fog and low stratus mask maps over East Greenland with associated fog statistics. Six days throughout the 2002–2007 melt season are mapped, revealing maximum fog extent in July–August covering 20,000–70,000 km2 of glacier surface. Mean fog thickness is ∼200 m and maximum inland extent of continuous fog ∼100 km, although patches occur high on the ice sheet. Our method and results will aid in cloud change detection and in the quantification of cloud radiative forcing and thermal effects over snow and ice surfaces.