[论文解读] Integrated monitoring of ice in selected Swiss lakes. Final project report

Manu Tom, Melanie Sütterlin+4 more|arXiv (Cornell University)|Aug 2, 2020

Arctic and Antarctic ice dynamics参考文献 59被引用 6

一句话总结

本研究提出了一种综合方法，利用卫星影像（MODIS/VIIRS）、公共网络摄像头和现场测量数据，监测瑞士阿尔卑斯湖泊的湖冰状况，以确定结冰开始和融冰结束日期。该研究成功整合多源数据，提高了检测精度，尤其在圣莫里茨等小型湖泊中表现显著，证明了多平台监测系统在气候相关湖冰变量监测中的可行性。

ABSTRACT

Various lake observables, including lake ice, are related to climate and climate change and provide a good opportunity for long-term monitoring. Lakes (and as part of them lake ice) is therefore considered an Essential Climate Variable (ECV) of the Global Climate Observing System (GCOS). Following the need for an integrated multi-temporal monitoring of lake ice in Switzerland, MeteoSwiss in the framework of GCOS Switzerland supported this 2-year project to explore not only the use of satellite images but also the possibilities of Webcams and in-situ measurements. The aim of this project is to monitor some target lakes and detect the extent of ice and especially the ice-on/off dates, with focus on the integration of various input data and processing methods. The target lakes are: St. Moritz, Silvaplana, Sils, Sihl, Greifen and Aegeri, whereby only the first four were mainly frozen during the observation period and thus processed. The observation period was mainly the winter 2016-17. During the project, various approaches were developed, implemented, tested and compared. Firstly, low spatial resolution (250 - 1000 m) but high temporal resolution (1 day) satellite images from the optical sensors MODIS and VIIRS were used. Secondly, and as a pilot project, the use of existing public Webcams was investigated for (a) validation of results from satellite data, and (b) independent estimation of lake ice, especially for small lakes like St. Moritz, that could not be possibly monitored in the satellite images. Thirdly, in-situ measurements were made in order to characterize the development of the temperature profiles and partly pressure before freezing and under the ice-cover until melting. This report presents the results of the project work.

研究动机与目标

• 开发一种利用多种数据源监测瑞士湖冰的综合监测系统。
• 评估使用低空间分辨率、高时间分辨率卫星数据（MODIS/VIIRS）检测结冰和冰层破裂的可行性。
• 评估公共网络摄像头作为验证和独立监测工具的作用，尤其针对卫星分辨率有限的小型湖泊。
• 收集现场水温与压力剖面数据，以更好地理解结冰和冰层覆盖的动力学过程。
• 建立多源数据框架，用于长期监测湖冰作为关键气候变量（ECV）。

提出的方法

• 利用空间分辨率为250–1000米的MODIS和VIIRS每日卫星图像，对湖冰范围进行时间序列监测。
• 实施自动化图像处理技术，基于地表反照率和光谱反射率变化检测冰层覆盖。
• 利用现有的公共网络摄像头进行视觉验证和独立冰层检测，尤其针对圣莫里茨等卫星分辨率不足的湖泊。
• 收集现场水温剖面和冰层压力数据，以表征结冰过程和冰层稳定性。
• 整合卫星、网络摄像头和现场数据的结果，以提高结冰和融冰日期检测的准确性和鲁棒性。
• 对比和验证各数据源的结果，以评估多平台方法的一致性和可靠性。

实验结果

研究问题

• RQ1 低空间分辨率、高时间分辨率的卫星数据能否可靠检测瑞士湖泊的结冰和融冰日期？
• RQ2 公共网络摄像头在多大程度上可作为湖冰监测的补充或独立数据源，尤其针对小型湖泊？
• RQ3 现场水温与压力测量数据如何有助于理解湖冰的结冰和消融过程？
• RQ4 整合卫星、网络摄像头和现场数据在监测湖冰作为关键气候变量方面有何附加价值？
• RQ5 与单一数据源方法相比，多源方法如何提升检测准确性？

主要发现

• MODIS和VIIRS卫星数据的整合实现了对结冰和融冰事件的稳定检测，时间分辨率达到每日一次。
• 公共网络摄像头提供了宝贵的视觉验证，并成功检测到圣莫里茨等小型湖泊的冰层，而这些湖泊的卫星数据因分辨率过低而难以实现可靠检测。
• 现场测量揭示了结冰和冰层覆盖期间的详细热分层与压力动力学，支持对过程机制的理解。
• 多源方法显著提升了检测可靠性，尤其在复杂或小型湖泊环境中表现突出。
• 成功确定了目标湖泊的结冰和融冰日期，其中圣莫里茨因面积小且暴露度高，表现出明显的结冰延迟。
• 本项目证明了在GCOS框架下，多平台湖冰监测系统作为关键气候变量的可行性与附加价值。