Integration of MODIS-derived metrics to assess interannual variability in snowpack, lake ice, and NDVI in southwest Alaska.
Integration of MODIS-derived metrics to assess interannual variability in snowpack, lake ice, and NDVI in southwest Alaska.
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DOI：
10.1016/j.rse.2008.07.020
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发表时间：
2009-07
影响因子：
13.5
通讯作者：
B. Reed;M. Budde;Page Spencer;Amy E. Miller
中科院分区：
文献类型：
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作者：
B. Reed;M. Budde;Page Spencer;Amy E. Miller
全球气候变化的影响预计将导致阿拉斯加西南部积雪、湖冰和植被动态的季节性变化更大。所有这些都对该区域的物理和生物生态系统产生广泛影响。我们使用中分辨率成像光谱仪（MODIS）校准的辐射，积雪覆盖范围，植被指数产品解释积雪，湖冰，植被动态的持续时间和范围的年际变化为阿拉斯加西南部。该方法集成了跨大生态区域的多个季节性指标。在整个观察期间（2001-2007年），积雪覆盖时间是稳定的生态区域内，可变的开始和结束日期。湖冰季节的开始比雪季节晚了2到3个月。在一个特定的湖泊，冻结日期的时间和持续时间各不相同，而打破日期更一致。植被物候的变化小于冰雪指标，季节开始日期在不同年份之间相对一致。生长季节的开始和积雪融化是相互关联的，因为它们都依赖于温度。2002-2003年厄尔尼诺冬季的气温高于平均气温，表现为异常的冰雪季节模式。我们正在开发一个一致的，基于MODIS的数据集，将用于监测这些季节性指标的时间趋势，并绘制研究区域的变化区域。
Impacts of global climate change are expected to result in greater variation in the seasonality of snowpack, lake ice, and vegetation dynamics in southwest Alaska. All have wide-reaching physical and biological ecosystem effects in the region. We used Moderate Resolution Imaging Spectroradiometer (MODIS) calibrated radiance, snow cover extent, and vegetation index products for interpreting interannual variation in the duration and extent of snowpack, lake ice, and vegetation dynamics for southwest Alaska. The approach integrates multiple seasonal metrics across large ecological regions. Throughout the observation period (2001–2007), snow cover duration was stable within ecoregions, with variable start and end dates. The start of the lake ice season lagged the snow season by 2 to 3 months. Within a given lake, freeze-up dates varied in timing and duration, while break-up dates were more consistent. Vegetation phenology varied less than snow and ice metrics, with start-of-season dates comparatively consistent across years. The start of growing season and snow melt were related to one another as they are both temperature dependent. Higher than average temperatures during the El Niño winter of 2002–2003 were expressed in anomalous ice and snow season patterns. We are developing a consistent, MODIS-based dataset that will be used to monitor temporal trends of each of these seasonal metrics and to map areas of change for the study area.