Timing and duration of ephemeral Antarctic water tracks and wetlands using high temporal–resolution satellite imagery, high spatial–resolution satellite imagery, and ground-based sensors in the McMurdo Dry Valleys
Timing and duration of ephemeral Antarctic water tracks and wetlands using high temporal–resolution satellite imagery, high spatial–resolution satellite imagery, and ground-based sensors in the McMurdo Dry Valleys
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DOI：
10.1080/15230430.2022.2123858
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发表时间：
2022-10
期刊：
影响因子：
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通讯作者：
L. Kuentz;J. Levy;M. Salvatore
中科院分区：
文献类型：
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作者：
L. Kuentz;J. Levy;M. Salvatore
摘要南极水迹和短暂的湿地是导致冷沙漠土壤形成的地球化学土壤过程的主要场所。虽然在绘制高分辨率商业卫星图像暗像素图的基础上，绘制了麦克默多干旱河谷水迹和湿润土壤的空间范围，但水迹和湿地形成的时间尺度以及这些地球化学活跃环境的持续时间仍然未知。在这里，我们确定的开始日期和结束日期和湿润土壤的持续时间在10个地点位于整个MDV使用的组合原位土壤传感器和两个互补的远程成像平台（行星和WorldView），以了解水文气候过程，驱动水的轨道和湿地的形成。我们的遥感采用了地形校正工作流程，消除了差分直接照明和小规模阴影对像素亮度的影响，减少了误报（土壤被识别为湿润，而实际上它们由于高相位角而被阴影或变暗）。我们的研究结果延长了一个多月的水跟踪和湿地水文周期，显示从11月到3月发生变暗，这表明水文的贡献，从地面冰融化，融雪，盐潮解和土壤盐水的增长。
ABSTRACT Antarctic water tracks and ephemeral wetlands are a primary location for biogeochemical soil processes driving cold desert soil formation. Though the spatial extent of water tracks and wetted soils has been mapped in the McMurdo Dry Valleys (MDV) on the basis of mapping darkened pixels in high-resolution commercial satellite imagery, the timescale over which water tracks and wetlands form and the duration of these biogeochemically active environments remain unknown. Here, we determine the start date and end dates and the duration of wetted soils at ten sites located across the MDV using a combination of in situ soil sensors and two complementary remote imaging platforms (Planet and WorldView) to understand the hydroclimatic processes that drive water track and wetland formation. Our remote sensing employs a terrain correction workflow that removes the contribution of differential direct illumination and small-scale shadowing on pixel brightness, reducing false positives (soils identified as wetted when in fact they are shadowed or darkened as a consequence of high phase angle). Our findings extend the water track and wetland hydroperiod by over a month, showing darkening occurring from November to March, suggesting hydrological contributions from ground ice thaw, snowmelt, and salt deliquescence and soil brine growth.