协同高光谱与激光雷达的湿地芦苇地上氮储量估算研究

芦苇地上氮储量对湿地生态系统氮循环研究和水体富营养化治理具有重要意义。传统的植被氮储量样点测量法不能满足区域尺度氮循环研究和富营养化修复的应用需求。遥感直接监测地上氮储量缺乏机理支撑，但可通过地上生物量和氮浓度联合估算。而生物量和氮浓度遥感建模时，大多未综合考虑植被冠层和三维垂直结构，限制了其估算精度。本项目以洪泽湖自然保护区芦苇湿地为研究区，基于无人机平台，获取激光雷达（LiDAR）和高光谱数据，结合地面调查数据，构建融合高光谱与LiDAR的芦苇地上生物量估算模型；考虑芦苇冠层结构和氮浓度垂直分布不均一性特征，构建冠层高度估算模型、氮浓度垂直分布模型、上层氮浓度遥感反演模型，提出芦苇地上氮浓度估算方法；最终，耦合生物量和氮浓度遥感模型，实现区域尺度芦苇地上氮储量的估算，并分析研究区地上氮储量的时空变化特征。研究结果可为湖泊/湿地富营养化治理和湿地生态系统氮循环研究提供理论基础和数据支撑。

It is very important to monitor Phragmites nitrogen storage for control water and wetland eutrophication and nitrogen cycle research. The traditional method for measuring nitrogen storage of wetland vegetation cannot demand for practical application. However, because of the lack of spectral mechanism, nitrogen storage cannot be derived directly from remote sensing. Therefore, in this project, we will select typical Phragmites wetland located in Hongze Lake national wetland protection reserve as study area, and the LiDAR and hyperspectral data will be acquired by UAV platform. Combining with ground synchronous measured data, the following researches will be conducted: 1) to establish the estimated model for aboveground biomass of Phragmites combining LiDAR and hyperspectral data; 2) to build canopy height model, nitrogen concentration model of vertical distribution, nitrogen concentration remote sensing reversion model, and then established estimated model for aboveground nitrogen concentration of Phragmites; 3) to calculate and map nitrogen storage in study area based on biomass and nitrogen concentration models, and then analyze its temporal and spatial changes and influences.