Multi-frequency microwave remote sensing of summer Arctic sea ice attributes as indicators of climate and biophysical processes

在过去的30年里，夏季北极海冰面积迅速减少，导致北极海洋环境的命运和北极利益攸关方的协调存在不确定性。现在有了一个全新的北极冰群，以较薄的第一年冰(FYI)为主，而不是较厚的多年冰(MyI)。夏季冰上低反照率融化池塘的面积分数，称为池塘分数(PF)，由于与粗糙的Myi相比，FYI上对洪水范围的地形控制较少，因此池塘分数(Pf)有所增加。一些实地研究指出，PF的演变与短波辐射吸收、光透射率、上层海洋变暖、冰下初级生产以及包括污染物在内的大气-海洋生物地球化学交换的速率相耦合。在区域和更大的尺度上，我们对局部尺度、演变以及与北极海洋环境组成部分的关系的理解是不一致的。推而广之，大尺度海冰模式中的Pf参数，主要基于MYI的局部尺度观测，不足以可靠地预测区域和盆地范围的海冰和气候条件。在所有尺度上，季节内熔融状态变化对PF演化和耦合过程的影响还知之甚少。需要一种强有力的手段来监测和评估夏季冰的季节性衰退和相关的生物物理过程。

In the last 30 years, summer Arctic sea ice extent has rapidly declined, leading to uncertainties regarding the fate of the Arctic marine environment and the coordination of Arctic stakeholders. There is now an entirely new Arctic ice pack dominated by thinner first-year ice (FYI) instead of thicker multiyear ice (MYI). The areal fraction of low albedo melt ponds on summer ice, termed pond fraction (PF), has increased due to fewer topographical controls on flooding extent over FYI compared to rough MYI. Several field studies point to the coupling of PF evolution to rates of shortwave radiation absorption, light transmittance, upper ocean warming, under-ice primary production, and atmosphere-ocean biogeochemical exchanges, including contaminants. Our understanding of local scale PF evolution and relationships with components of the Arctic marine environment is not matched at regional and greater scales. By extension, parameterizations of PF in large scale sea ice models, largely based on local scale observations of MYI, are inadequate for reliable regional and basin-wide forecasts of sea ice and climate conditions. At all scales the impact of intra-seasonal melting state variations on PF evolution and coupled processes are poorly understood. A robust means by which to monitor and assess the seasonal decay of summer ice and related biophysical processes is needed.