Lake-atmosphere interactions at northern high latitudes: Remote sensing and process studies

世界气象组织(WMO)的全球气候观测系统(GCOS)已将湖泊列为其基本气候变量(ECV)之一。在被确认为气候变化敏感指标的湖泊变量中，有湖泊表面温度、湖泊面积、湖泊水位，最近增加的还有冰冻和融化日期。这十年已经并将继续看到空间机构发射数量空前的地球观测卫星，这将提供一个非同寻常的机会来观测高纬度北部地区这些湖泊性质的变化和可变性。与此同时，可以填补现场测量和卫星图像之间关键测量差距的无人机(UAV)正越来越多地可用于快速部署，以捕捉更多发生在更短时间尺度上的湖泊属性的局部变化。 利用来自这些新兴遥感技术的数据，拟议的研究将：(1)开发基于卫星的湖泊属性反演算法和产品，侧重于冰上的冰覆盖范围/物候、厚度和积雪深度；(2)开展过程研究，旨在增进我们对哈德逊湾低地大而深的湖泊(大奴湖)和浅水湖泊/池塘对大气强迫的响应的理解，这些响应是在冰和公开水域季节的次日至季节性时间尺度上进行的。将特别注意湖泊在过渡期(冰到开阔水域和开阔水域到结冰；浮冰到浅湖上的搁浅冰)、延长的湿润和干旱期以及更极端/快速事件(例如，在持续几小时的强降雨之后、持续几天的积雪融化、风暴期)的反应。 该研究计划将首次生产：(1)气候评估、冬季航运作业和数值天气预报所需的高时间(1-2天)和空间分辨率(300米大型湖泊；30米小型北极湖泊)的全球/区域卫星获取的冰范围和物候产品；(2)气候评估和改进湖泊模型所需的冰厚度和冰雪产品。它还将产生关于浅水湖和大奴湖在空间和时间分辨率上对大气强迫的区域反应的新知识，现在可以通过新的卫星飞行任务和无人机观察到。尤其是来自无人机的观测，将有助于记录和澄清冰面和开阔水面对极端天气事件的反应，这些事件随着气候变暖而变得越来越频繁。

The Global Climate Observing System (GCOS) of the World Meteorological Organization (WMO) has recognized “Lakes” as one of its Essential Climate Variables (ECVs). Amongst the lake variables identified as sensitive indicators of climate change are lake surface temperature, lake area, lake water level, and more recently added are ice freeze-up and break-up dates. This decade has seen and will continue to see the launch of an unprecedented number of Earth Observation satellites from space agencies that will offer an extraordinary opportunity to observe changes and variability in these lake properties over high-latitude northern regions. This also happens at a time when unmanned aerial vehicles (UAVs), which can fill a critical measurement gap between field measurements and satellite imagery, are increasingly becoming available for rapid deployment in order to capture more local changes in lake properties occurring at even shorter time scales. Using data from these emerging remote sensing technologies, the proposed research will: (1) develop satellite-based retrieval algorithms and products of lake properties, focusing on ice cover extent/phenology, thickness and snow depth on ice; and (2) conduct process studies aimed at advancing our understanding of the response of a large, deep, lake (Great Slave Lake) and shallow lakes/ponds of the Hudson Bay Lowlands to atmospheric forcing on sub-daily to seasonal time scales during the ice and open water seasons. Particular attention will be paid to the response of lakes during transition periods (ice to open water and open water to ice; floating ice to grounded ice on shallow lakes), extended wet and dry periods, and more extreme/rapid events (e.g. following intense rainfall lasting a few hours, snowmelt lasting a few days, wind storms). The research program will produce for the first time: (1) global/regional satellite-derived ice extent and phenology products at both high temporal (1-2 days) and spatial resolutions (300 m large lakes; 30 m small Arctic lakes) required for climate assessments, winter shipping operations and numerical weather forecasting; and (2) ice thickness and snow-on ice products needed for climate assessments and improvement of lake models. It will also generate new knowledge on the regional response of shallow lakes and Great Slave Lake to atmospheric forcing at spatial and temporal resolutions now observable with new satellite missions and UAVs. Observations from a UAV, in particular, will help document and clarify the response of ice and open water surfaces to extreme weather events that are becoming more frequent with climate warming.