2018-03-012024-05-16https://scholars.lib.ntu.edu.tw/handle/123456789/668782摘要：近年來，每當極端天氣事件發生時，全球暖化和氣候變遷即登上新聞頭條。各國在2015年聯合國氣候變遷會議上達成了一項協議，將全球氣溫上升在本世紀末以前限制在攝氏2度以下。包括美國、歐盟、日本和中國都已經在2016年批准了這項協議。 遙測技術可以在執行這項協議時發揮重要作用，但相關技術將面臨新的要求和挑戰，以進一步改進和整合。現代雷達技術已被應用於檢測沙塵暴，而雷射測距雷達技術似乎更適合於檢測具有比沙塵顆粒更小的氣溶膠。沙塵/氣溶膠分佈會影響遙測設備的運作，後者則可用於檢測前者。合成孔徑雷達 (SAR) 技術用於收集高空間和時間解析度的地面實況數據日受歡迎，也可用於監測與極端天氣和氣候變化相關的事件。 本計畫由四項任務組成： [1] 利用雷射測距雷達技術即時監測 。 [2] 採用有限差分時域 (FDTD) 法和輻射傳輸理論 (RT) 推算具粗糙表面介質的亮度溫度。 [3] 採用改進的變頻縮比例演算法 (CSA) 於高傾角的SAR成像。 [4] 採用改進的頻域演算法 (FDA) 於高離心率橢圓軌道 (HEO) 衛星的SAR成像。 在第一項任務中研擬的雷射測距雷達系統所得結果將與上一年度MOST計畫中所研究的毫米波雷達技術進行比較，在應用這些技術監測沙塵/氣溶膠分佈時將獲得更多的理解。 在第二項任務中整合FDTD 法與RT以預測被動遙測設備測量的亮度溫度。將分析沙塵/氣溶膠分佈對亮度溫度的影響，並提出採用後者預測沙塵/氣溶膠分佈的模型。 在第三項任務中提出四種改進的CSA演算法於在高傾角的SAR成像。常規方法在高傾角時需要更大的合成孔徑，更多的補償處理和計算量。所提新方法在圖像品質、計算量和記憶體需求等性能將與常規方法進行比較。 在第四項任務中研究在Tundra軌道中運行的HEO 衛星用於SAR成像的可行性，以具有覆蓋整個地球表面的能力。並提出一種改進的 FDA法來重建圖像，其性能將與常規方法進行比較。在第三和第四項任務中，將分析沙塵/氣溶膠分佈對圖像品質的影響，並且將探討利用這些SAR技術於檢測沙塵/氣溶膠分佈的可行性。後續將設想更多的新方法以在局部或廣泛區域上預測沙塵/氣溶膠分佈。<br> Abstract: In recent years, global warming and climate change were frequently spotlighted in headline news whenever an extreme weather event occurred. In the 2015 United Nations Climate Change Conference, an agreement was reached to constrain the global temperature rise to less than 2 degrees by the end of this century. Key players, including the United States, European Union, Japan and China, already sanctioned this agreement in 2016. Remote sensing technologies can play an important role in executing this agreement. New requirements and challenges will be imposed on relevant technologies, creating opportunities for further improvement and integration. Modern radar technologies have been applied to detect sand-and-dust storms, and lidar technologies seems more appropriate to detect aerosols with much smaller particles than sands and dusts. The sand/dust/aerosol distributions may affect the operation of remote sensing devices, which can also be used to detect the former. Synthetic aperture radar (SAR) technologies were gaining popularity for collecting the ground-truth data at high spatial and temporal resolutions, making them plausible for monitoring events related to extreme weathers and climate change. This project is composed of four tasks: [1] Real-time monitor of particle matter 2.5 ( ) with lidar technique. [2] Brightness temperature of media with rough surface via FDTD method and radiative transfer theory. [3] Improved chirp scaling algorithms for SAR imaging at high squint angles. [4] SAR imaging on HEO satellites with an improved frequency-domain algorithm. In the first task, a lidar system configuration is proposed to monitor in real time, which will be compared with the radar techniques studied in the previous MOST project. More understanding will be gained in applying these techniques to monitor sand/dust/aerosol distributions. In the second task, a finite difference time domain (FDTD) method is integrated with the radiative transfer theory to predict the brightness temperature measured by passive remote-sensing devices. The effects of sand/dust/aerosol distributions on the brightness temperature will be studied, based on which a prediction model of the sand/dust/aerosol distributions can be proposed. In the third task, four improved chirp scaling algorithms (CSAs) are proposed for SAR imaging at high squint angles, which requires a larger synthetic aperture, more compensation processes and computational load, as compared to the conventional methods. The performance of the proposed methods will be compared with that of the conventional methods, in terms of image quality, computational load and memory. In the fourth task, the possibility of employing highly-elliptical-orbit (HEO) satellites in a Tundra orbit for SAR imaging is investigated, which has the capability of covering the whole globe surface. An improved frequency-domain algorithm (FDA) is proposed to reconstruct the image, of which the performance will be compared with that of the conventional method in terms of image quality, computational load and memory. In the third and the fourth tasks, the effects of sand/dust/aerosol distributions on the image quality will be analyzed, and the possibility of detecting sand/dust/aerosol distributions with these SAR techniques will be explored. More new methods will be conceived for predicting sand/dust/aerosol distributions, over local or wide areas.遙測雷射測距雷達合成孔徑雷達沙塵氣溶膠亮度溫度有限差分時域法輻射傳輸理論變頻縮比例演算法高離心率橢圓軌道衛星頻域演算法。remote sensinglidarsynthetic aperture radar (SAR)sanddustaerosolbrightness temperaturefinite difference time domain (FDTD)radiative transfer theorychirp scaling algorithm (CSA)highly-elliptical-orbit (HEO)satellitefrequency-domain