Application of MODIS snow cover products: wildfire impacts on snow and melt in the Sierra Nevada
Application of MODIS snow cover products: wildfire impacts on snow and melt in the Sierra Nevada
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MODIS积雪产品的应用：野火对内华达山脉积雪和融化的影响
DOI：
10.5194/hess-18-4601-2014
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发表时间：
2014
影响因子：
6.3
通讯作者：
T. Hogue
中科院分区：
文献类型：
--
作者：
P. Micheletty;A. Kinoshita;T. Hogue
利用中分辨率成像光谱仪（MODIS）的积雪覆盖面积和粒度（MODSCAG）数据，对北方加州的一场森林大火后积雪的时空变化进行了研究。利用MODISMOD 10A 1分数积雪覆盖面积和MODSCAG分数积雪产品检测积雪的时空变化后，2007年月光火和未燃烧的盆地，灰熊岭，水年（WY）2002-2012。冠层调整和非调整MODSCAG分数积雪覆盖面积（fSCA）的估计进行平滑和插值，以提供一个连续的时间序列的平均日积雪范围在两个盆地。野火移除上层树冠暴露更多的积雪覆盖，然而，元素像素比较和统计分析表明，MOD 10A 1产品有一种倾向，高估火灾前的积雪覆盖，静音观察到的野火的影响。MODSCAG算法更好地区分亚像素的积雪覆盖在森林地区，是高度相关的火灾后土壤烧伤的严重程度。年度MODSCAG fSCA估计值显示，与火灾前平均值和对照流域相比，火灾后月光火研究区域的fSCA在统计学上显著增加（2008-2011年WY的P < 0.01）。火灾发生后，超过火灾前高积雪阈值的天数增加了81%。林冠减少增加了暴露的可见积雪面积和到达积雪的太阳辐射量，导致盆地平均融化日期比附近未燃烧的盆地更早。无论坡度或烧伤严重程度如何，火灾后MODSCAG fSCA也显著增加。区域积雪变化对受影响的生态系统、下游社区和资源管理者的短期和长期供水都有重大影响。
The current work evaluates the spatial and temporal variability in snow after a large forest fire in northern California using Moderate Resolution Imaging Spectroradiometer (MODIS) snow-covered area and grain size (MODSCAG). MODIS MOD10A1 fractional snow-covered area and MODSCAG fractional snow cover products are utilized to detect spatial and temporal changes in snowpack after the 2007 Moonlight Fire and an unburned basin, Grizzly Ridge, for water years (WY) 2002–2012. Estimates of canopy-adjusted and non-adjusted MODSCAG fractional snow-covered area (fSCA) are smoothed and interpolated to provide a continuous time series of average daily snow extent over the two basins. The removal of overstory canopy by wildfire exposes more snow cover; however, elemental pixel comparisons and statistical analysis show that the MOD10A1 product has a tendency to overestimate snow coverage pre-fire, muting the observed effects of wildfire. The MODSCAG algorithm better distinguishes subpixel snow coverage in forested areas and is highly correlated to soil burn severity after the fire. Annual MODSCAG fSCA estimates show statistically significant increased fSCA in the Moonlight Fire study area after the fire ( P < 0.01 for WY 2008–2011) compared to pre-fire averages and the control basin. After the fire, the number of days exceeding a pre-fire high snow-cover threshold increased by 81%. Canopy reduction increases exposed viewable snow area and the amount of solar radiation that reaches the snowpack, leading to earlier basin average melt-out dates compared to the nearby unburned basin. There is also a significant increase in MODSCAG fSCA post-fire regardless of slope or burn severity. Regional snow cover change has significant implications for both short- and long-term water supply for impacted ecosystems, downstream communities, and resource managers.