2016-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/709685摘要：本計畫由五項任務組成： [1] 採用LEO-地面紅外線雷射掩星（LGIO）技術推估主要溫室氣體分佈。 [2] 採用地面無線電掩星技術推估折射率高度分佈。 [3] 毫米波在沙塵暴中之衰減效應。 [4] 粒子模擬沙塵暴造成之毫米波逆向散射。 [5] 沙塵暴對X波段微波鏈路之衰減效應。 溫室氣體是導致全球暖化和氣候變化的主因。第一個任務採用LGIO技術推估溫室氣體的分佈，可實際監測區域天氣和氣候的變化。採用和聲搜尋（HS）演算法推估三大溫室氣體的體積混合比分佈，包括低空水氣的吸收作用。 第二個任務採用地面無線電掩星（RO）技術推估大氣折射率分佈，使區域天氣研究更精準。為獲得更精確的折射率分佈，射線追&#36394;模型中的積分上限需提高。採用和聲搜尋（HS）結合基於大氣物理的集合考慮（HS-EC），得以更有效地找出最佳解。 由於全球氣候暖化，沙塵暴（SDS）發生的次數比以前頻繁。毫米波信號通過SDS會衰減，一部分將被逆向散射。第三個任務採用拋物線波方程（PWE）技術模擬毫米波在SDS中傳播所受的吸收和瑞利散射效應，並提出實用的量測設置方式。 第四個任務提出粒子模擬技術以模擬雷達波束穿透SDS的逆向散射功率，並與常規雷達方程的預測比較。第五個任務模擬一個移動的SDS造成微波衰減的時間變化，並與測量數據進行比較。 請概述執行本計畫可能產生對社會、經濟、學術發展等面向的預期影響性(一百五十字內)。 在巴黎舉行的2015年聯合國氣候變化大會上，已對溫室氣體的減排達成共識，設定目標限制全球暖化在本世紀結束前低於 或 。本計畫提出了數種技術來監測溫室氣體及低層大氣中的折射率分佈，此二分佈為主導全球暖化的關鍵。另提出毫米波技術來估計沙塵暴（SDS）規模，防範其對人類生命和財產的威脅。本計畫的執行成果有助於相關行業提升技術和產品，包括傳感器、通信設備和服務。政府主管部門也可用來制訂溫室氣體監測和排放控制政策。 <br> Abstract: This proposal is composed of five tasks: [1] Retrieval of major greenhouse gas profiles with LEO-ground infrared laser occultation (LGIO) technique. [2] Retrieval of refractivity profile with ground-based radio occultation (RO) technique. [3] Attenuation of millimeter-wave in a sand and dust storm. [4] Backscattering of millimeter-wave from a sand and dust storm with particle simulations. [5] Attenuation of sand and dust storm on an X-band microwave link. Greenhouse gases (GHGs) are the major factors that cause global warming and climate change. In the first task, a LEO-ground infrared laser occultation (LGIO) technique is proposed to retrieve regional greenhouse gas profiles, which is practical for monitoring regional weather and climate change. A harmony search (HS) algorithm with ensemble consideration is applied to retrieve the volume mixing ratio (VMR) profiles of three major GHGs ( , and ) and . The strong absorption by at low altitudes is also considered to acquire accurate VMR profiles. In the second task, a ground-based radio occultation (RO) technique is proposed to retrieve the atmospheric refractivity profile at a higher sampling rate and a finer spatial resolution than its space-based counterpart, leading to a more suitable technique for regional weather studies. In order to retrieve a more accurate refractivity profile, the upper bound of an integral derived in the ray tracing model is extended, which increases the number of unknowns. A harmony search (HS) method with ensemble consideration (HS-EC) based on atmospheric physics is proposed to search the optimal solution more efficiently while avoiding suboptimal solutions. Sand and dust storms (SDSs) occur more frequently than before, due to the extreme weather conditions related to global warming. Millimeter-wave signal propagating through an SDS will be attenuated, and part of it will be back-scattered. These attenuation and back-scattering signatures can be used to probe an SDS for its parameters. In the third task, the attenuation of millimeter-wave signals in an SDS is used to retrieve its parameters. A parabolic wave equation (PWE) technique is applied to simulate millimeter-wave propagation in an SDS, by modeling the latter as a lossy inhomogeneous medium, including the effects of absorption and Rayleigh scattering by dust particles with given distributions of radius and total number density. Practical setups for effectively measuring the wave attenuation will also be studied. In the fourth task, a particle simulation technique is proposed to simulate the backscattered power of a radar beam penetrating an SDS. The forward wave is computed by applying a PWE technique, Rayleigh scattering is incorporated in simulating both the forward and the backward waves. Predictions by using conventional radar equation will also be calculated for comparison. Microwave signals propagating through an SDS will be attenuated, leading to poor communications quality. In the fifth task, a moving SDS is simulated, with the height profiles of particle number density and total number density related to visibility measurement. The simulated temporal variation of microwave attenuation will be compared with measurement data to verify the efficacy of the proposed method. 請概述執行本計畫可能產生對社會、經濟、學術發展等面向的預期影響性(一百五十字內)。 The 2015 United Nations Climate Change Conference in Paris, France reached a global agreement on the reduction of greenhouse gas emissions. A goal was set to limit global warming to less than or before the end of this century. This project proposes several advanced technologies to monitor greenhouse gases and refractivity profiles in the atmosphere, both are key factors that dominate global warming. A forward and a backward millimeter-wave technologies are also proposed for retrieving parameters of sand and dust storms (SDSs), to prevent their threats to human lives and properties. This project will create useful methods and information for relevant industries to upgrade their technologies and products in sensors, communications devices and services. Government authorities can also use the results to make policies in monitor and control of greenhouse gas emissions as well as air pollution.無線電掩星紅外線雷射低地球軌道溫室氣體和聲搜尋折射率分佈全球定位系統沙塵暴毫米波瑞利散射衰減拋物線波方程粒子模擬逆散射雷達方程式微波鏈路。radio occultation (RO)infrared-laserlow earth orbit (LEO)greenhouse gasharmony search (HS)refractivity profileglobal positioning system (GPS)sand and dust storm (SDS)millimeter-waveRayleigh scatteringattenuationPWE