Effects of bark beetle-caused tree mortality on biogeochemical and biogeophysical MODIS products
Effects of bark beetle-caused tree mortality on biogeochemical and biogeophysical MODIS products
复制标题
DOI：
10.1002/jgrg.20078
复制
发表时间：
2013-07-01
影响因子：
3.7
通讯作者：
Meddens, Arjan J. H.
中科院分区：
文献类型：
--
作者：
Bright, Benjamin C.;Hicke, Jeffrey A.;Meddens, Arjan J. H.
干扰影响森林-大气中碳、水和能量的交换，从而影响天气和气候。树皮甲虫暴发是这样一种干扰类型，它改变了森林中的生物地球化学和生物地球物理过程。很少有研究通过卫星观测记录树皮甲虫对叶面积指数(LAI)、总初级生产力(GPP)、蒸散(ET)、地表温度(LST)和地表反照率的影响。我们的目标是使用陆地卫星对树皮甲虫引起的树木死亡的估计和中分辨率成像光谱仪(MODIS)陆地表面产品来估计甲虫引起的科罗拉多州北部LAI、GPP、ET、LST和地表反照率的变化。树皮甲虫引起的树木死亡后，叶面积指数(0.02-0.80m(-2)m(-2)，1-40%)、年GPP(50-248gm(-2)年(-1)，(5-26%)和夏季逐日蒸散量(0.20-0.70 mm/d(-1)，13-44%)出现下降，而8月份LST(1-3.9K)和2月份反照率(0.03-0.09，19-52%)出现增加。我们发现，在死亡率较高的地区，这些变量的反应更大。科罗拉多州北部树木死亡的程度和严重程度导致我们研究区域所有林区的平均地表变量发生了重大变化(9-23%)。我们的结果表明，地表变量对树皮甲虫引起的树木死亡很敏感，树皮甲虫的暴发可以显著影响生物地球化学和生物地球物理过程。
Disturbances affect forest-atmosphere exchanges of carbon, water, and energy, thereby influencing weather and climate. Bark beetle outbreaks are one such disturbance type that alters biogeochemical and biogeophysical processes in forests. Few studies have documented bark beetle impacts to leaf area index (LAI), gross primary productivity (GPP), evapotranspiration (ET), land surface temperature (LST), and surface albedo with satellite observations. Our objective was to use Landsat-derived estimates of bark beetle-caused tree mortality and Moderate Resolution Imaging Spectroradiometer (MODIS) land surface products to estimate beetle-caused changes in LAI, GPP, ET, LST, and surface albedo in northern Colorado. Following bark beetle-caused tree mortality, decreases occurred in LAI (0.02-0.80 m(2)m(-2), 1-40%), annual GPP (50-248 gC m(-2)yr(-1), (5-26%), and daily summer ET (0.20-0.70mmday(-1), 13-44%), whereas increases occurred in August LST (1-3.9K) and February albedo (0.03-0.09, 19-52%). We found greater responses of these variables in areas of greater mortality severity. The extent and severity of tree mortality in northern Colorado caused substantial changes in land surface variables (9-23%) when averaged across all forested areas of our study area. Our results demonstrate that land surface variables are sensitive to bark beetle-caused tree mortality and that bark beetle outbreaks can significantly impact biogeochemical and biogeophysical processes.