强热交换条件下温排水皮温-体温对典型环境要素变化的响应机制及无人机遥感识别研究

During the survey of thermal discharge with remote sensing technique， the warming of the water in the mixing zone aggravates the strength of the heat exchange at the upper surface water, which changes the original “skin-bulk” temperature distribution structure and reduces the precision of retrieved temperature distribution. Underestimation of mixing zone is inevitably. In the meanwhile, it’s hard to mosaic UAV images for lack of necessary matching features, because the entire field of view is filled with nothing but waters.. The integration of UAV and infrared sensors can provide long-term and high-quality observation data with no restrictions such as landing condition or overpass time, Which makes it possible to monitoring thermal discharge in different tidal state. Using UAV thermal infrared imaging technology, this research focus on the mechanism of skin temperature and bulk temperature variation against typical environmental factors under strong heat exchange condition and carries out three aspects of work to monitoring and recognizing thermal discharge from Hongyanhe power plant. 1) The mechanism of skin temperature and bulk temperature variation against typical environmental factors under strong heat exchange condition is researched by theoretical analysis and experimental tests. 2) Based on the analysis of mechanism, correction model is constructed in order to reduce the error on skin temperature retrieval caused by environmental factors, which could improve the accuracy of temperature field observation assisted with heat flux analytical method. 3) A seamless robust mosaicking method is established with multi-source features extracted, in order to recognize thermal discharge distribution precisely. This proposal tends to provide ideas for thermal discharge environmental post-assessment and supervision method.

温排水混合区内水体掺混升温加剧表层水体热交换强度，打破原有“皮-体温度”分布结构，降低了遥感建模反演水体温度精度，导致温升范围的错误估算；同时，全水域成像致使图像拼接缺失必要匹配特征，拼接难度大且精度差。.无人机遥感可提供长时序高质量观测数据，无过境时间及起降条件限制，为不同潮态温排水监测提供了契机。本课题采用无人机热红外成像技术，以强热交换条件下温排水皮温-体温对典型环境影响要素的响应机制分析为突破口，开展三方面研究：1）通过室内实验设计与分析，揭示强热交换条件下温排水皮温-体温对典型环境要素变化的响应机制；2）基于响应机制分析，构建温排水皮温环境要素影响修正模型，提高水体温度场反演精度；3）提取并集成无人机数据多源有效特征，建立面向全水域观测的无人机热红外影像鲁棒拼接方法，最终实现温排水扩散的无人机遥感精确识别。本研究成果可为温排水环评及监管提供思路。

随着我国滨海核电建设项目及装机容量的不断增加，循环冷却水直排海导致的温排水海洋环境影响备受关注。温排水潜排区内水体掺混升温加剧了表层水体热交换强度，打破原有相对稳定的“皮-体温度”垂向分布结构，降低了遥感手段以皮温（Skin Temperature）观测建模反演水体体温（Bulk Temperature）的精度，导致温升范围的错误估算，增加了温排水生态环境影响的监管难度；同时，潜排区内无人机遥感监测手段面临全水域成像所导致的同名点遍历难度大，航向及旁向相邻影像间拼接镶嵌缺失必要匹配特征的技术瓶颈。针对上述问题，课题研究采用无人机热红外技术，以海-气界面热交换与温排水皮-体温差的作用机理为切入点，设计并实施了室内实验，探索并揭示温排水皮-体温差对典型环境影响因素的响应机制；在机制分析基础上，构建了温排水温度场环境要素影响修正模型，显著提升温度场遥感反演精度；综合无人机平台惯导自定位信息及热红外影像空间域特征，实现了面向全水域成像的无人机热红外影像拼接方法，最终构建了面向核电温排水监测监管的无人机热红外遥感识别技术，并于红沿河核电站开展了实证应用，结果显示达到项目预期目标。本课题研究成果可为滨海核电站温排水监测监管及环境影响后评估提供技术支持。