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Passive microwave freeze/thaw classification for wet tundra regions

机译：湿潮汐地区的被动微波炉冻结/解冻分类

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Several climate change scenarios have predicted that the greatest changes would occur at high latitudes. In the Arctic, long-term changes in temperature would be reflected, for example, in the growth or retreat of permafrost regions and in the response of the vegetation. Tundra-covered areas are a major terrestrial reservoir of carbon and changes in temperature and moisture will affect the storage and release of carbon by the tundra. The most important annual hydrological events for tundra regions are the thaw in the spring and freeze-up in the fall. These regions are often cloud-covered for extended periods, especially during these key times of the year. A remote freeze/thaw classification technique based on microwave satellite measurements has the potential for providing more consistent observations compared with one based on visible observations. The authors begin by developing a classification technique from ground-based data (i.e., no intervening atmosphere) collected during the authors' Radiobrightness Energy Balance Experiment 3 (REBEX 3) on the North Slope of Alaska from September, 1994 until September, 1995. Radiobrightness measurements were made at 19.35, 37.0, and 85.5 GHz using a tower-mounted Special Sensor Microwave/Imager (SSM/I) simulator. Co-located surface energy balance measurements included: thermal IR surface brightness, solar and net radiation, soil and snowpack temperatures, soil heat flux, sensible heat, latent heat, soil moisture, and other related meteorological variables. REBEX 3 was conducted in conjunction with other interdisciplinary experiments under the Arctic System Science (ARCSS) program of the U.S. National Science Foundation. Using the spectral gradient, changes in the spectral gradient on a diurnal time scale, polarization effects, and absolute radiobrightnesses, a technique for classifying tundra as snow-free frozen, snow-free thawed, or snowcovered is described. Supporting measurements of subsurface temperature and moisture are used to understand the physical basis for the differing radiobrightness signatures.
机译：几种气候变化情景预测，在高纬度地区将发生最大的变化。在北极，温度的长期变化将被反映，例如，在多年冻土区的生长或撤退中，并在植被的响应中。苔原覆盖区域是碳的主要地面储层，温度和水分的变化会影响苔原的储存和释放碳。 Tundra地区最重要的年度水文事件是春天的解冻，秋季冻结。这些地区通常是云覆盖的延长时期，特别是在今年的这些关键时期。基于微波卫星测量的远程冻融/解冻分类技术具有与基于可见观察相比的更符合更一致的观察。作者首先从1994年9月到1995年9月的Alaska北坡上的基于基于地面的数据（即，没有干预气氛）的分类技术，从1994年9月到1995年9月到9月。射线rightnight使用塔架安装的特殊传感器微波/成像器（SSM / I）模拟器，在19.35,37.0和85.5 GHz下进行测量。包括协同定位的表面能量平衡测量：热敏IR表面亮度，太阳能和净辐射，土壤和积雪的温度，土壤热通量，显热，潜热，土壤湿度，以及其它相关的气象变量。 Rebex 3在美国国家科学基金会的北极系统科学（ARCS）计划下与其他跨学科实验结合进行。使用光谱梯度，在昼夜时间尺度，偏振效应和绝对辐射基础上的频谱梯度变化，描述了一种将TINDRA分类为无醋酸的冷冻，无雪冻结或雪板的技术。支持地下温度和水分的支持测量用于了解不同的辐射效应签名的物理基础。

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