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純轉(zhuǎn)動拉曼激光雷達探測對流層中底部大氣溫度

發(fā)布時間:2018-03-05 00:36

  本文選題:純轉(zhuǎn)動拉曼激光雷達 切入點:大氣溫度 出處:《中國科學技術(shù)大學》2017年博士論文 論文類型:學位論文


【摘要】:大氣溫度是表征大氣能量平衡的重要參數(shù)之一,高精度探測大氣溫度的時空變化規(guī)律具有重要的應(yīng)用價值和科研價值。激光雷達雖然是新興技術(shù),但由于其具有高時空分辨的優(yōu)勢,激光雷達已經(jīng)成為探測大氣溫度以及其他大氣參數(shù)的一種不可缺少的工具。在863項目"多源光譜層析及三維數(shù)值大氣關(guān)鍵技術(shù)"的支持下,我們研制了一臺多功能多通道激光雷達系統(tǒng),能夠同時、連續(xù)、高精度觀測近地面至對流層范圍的大氣溫度、水汽和氣溶膠,并且在合肥和北京兩地分別進行了觀測實驗,兩地觀測實驗都取得了與無線電探空氣球較一致的結(jié)果,主要研究內(nèi)容如下:(1)首先論述了激光雷達大氣遙感的理論背景和系統(tǒng)構(gòu)造,以及各類激光雷達探測技術(shù)。對大氣溫度的分布特征和常見的探測方法進行了概述,列舉了國內(nèi)外典型的大氣溫度探測激光雷達,簡述了最新測溫激光雷達的發(fā)展動態(tài)。(2)本文主要完成了一套能夠同時探測大氣溫度、水汽和氣溶膠的多功能多通道的集成式純轉(zhuǎn)動拉曼激光雷達。激光發(fā)射單元采用美國Continuum公司的Nd:YAG固體激光器,激光器輸出基頻波長為1064nm,經(jīng)由二倍頻和三倍頻分別輸出532nm和355nm的激光,355nm單脈沖激光輸出能量約為300mJ,脈沖頻率20Hz?ㄈ窳质酵h鏡具有焦距長、結(jié)構(gòu)緊湊的優(yōu)點,分別采用450mm 口徑大望遠鏡接收溫度和水汽的拉曼散射回波信號,300mm小口徑望遠鏡接收氣溶膠的米散射回波信號。利用干涉濾光片以一定的傾斜角度安裝在光學平臺上,可以實現(xiàn)對大氣回波信號的有效分光。數(shù)據(jù)采集單元采用瞬態(tài)記錄儀,它能同時收集數(shù)模信號。(3)分光系統(tǒng)的核心是干涉濾光片,模擬計算了干涉濾光片參數(shù)中心波長和帶寬與溫度測量不確定度的關(guān)系。用于探測大氣溫度的激發(fā)發(fā)射波長選為355nm的紫外光,激發(fā)光波長越短,后向散射微分截面越大,轉(zhuǎn)動拉曼信號越強,并且355nm處于可見光范圍外,更容易實現(xiàn)白天探測。模擬計算表明,高階轉(zhuǎn)動量子數(shù)拉曼通道的干涉濾光片中心波長對溫度探測精度更敏感。(4)激光雷達系統(tǒng)研制成功后分別在合肥和北京部分地域開展了近地面大氣溫度的觀測與分析,選用同時間點釋放的無線電探空氣球驗證儀器的可靠性。觀測資料表明了對流層溫度具有較明顯的時空分布特征。(5)本文重點分析了測量信號不確定度、不同時空分辨率和標定常數(shù)對溫度探測精度的影響。累積發(fā)射脈沖數(shù)越多,噪聲越小信噪比越大,測量信號不確定度越小。在累積激發(fā)脈沖數(shù)為10000發(fā)(5000發(fā))時,對應(yīng)30m、60m、120m和240m的空間分辨率,近地面至8km高度處溫度測量不確定度的均值分別為 1.09K(1.33K),0.83K(0.85K),0.78K(0.79K)和0.88K(0.89K)。標定常數(shù)a和b不僅影響溫度廓線的平移,還對溫度廓線的形狀有影響,標定常數(shù)c只影響溫度廓線的平移。根據(jù)觀測數(shù)據(jù)可知,a和c有相同的變化趨勢,b變化趨勢相反。當a、b和c變化趨勢相同時,利用公式反演溫度帶來的誤差較小,誤差有互相抵消的趨勢;當a、c變化和b變化趨勢相反時,利用公式反演溫度帶來的誤差較大。
[Abstract]:Air temperature is one of the important parameters characterizing the atmospheric energy balance, has important application value and research value of high precision detection of temporal and spatial variation of atmospheric temperature. Although the laser radar is a new technology, but because of its high spatial and temporal resolution, laser radar has become an indispensable measurement of atmospheric temperature and other atmospheric parameters of the tool in the 863 project "multi spectral tomography and 3D numerical atmospheric" key technology support, we developed a multi-function laser radar system, which at the same time, continuous, high precision measurement of atmospheric temperature near the ground surface to the troposphere range, water vapor and aerosol, and in Hefei and Beijing respectively were observed. The two observations are made is consistent with the results of the air ball on the radio, the main contents are as follows: (1) first, the laser radar Gas sensing theoretical background and system structure, and various types of laser radar technology. The distribution characteristics of the atmospheric temperature and the common detection methods are summarized, enumerates the atmospheric temperature detection laser radar at home and abroad, introduces the latest development of lidar. (2) this paper completed a at the same time, the detection of atmospheric temperature, the pure rotational Raman lidar integrated multiple channels of water vapor and aerosol. The laser emitting unit by Nd:YAG laser Continuum in the United States, the laser output wavelength of 1064nm laser frequency, frequency and frequency respectively by two three output 532nm and 355nm 355nm, the single pulse output energy is about 300mJ pulse frequency, 20Hz. Cassegrain telescope with long focal length, the advantages of compact structure, using the 450mm large aperture telescope receiving temperature and water vapor tension Raman scattering echo, Mie scattering echo signal receiving aerosol 300mm small caliber telescope. The interference filter with a skew mounted on the optical platform, can achieve effective light on the atmospheric echo signal. The data acquisition unit adopts transient recorder, it can simultaneously collect analog signals. (3) the core optical system the interference filter, simulated interference filter parameters of center wavelength and bandwidth and temperature measurement uncertainty. For the excitation emission wavelength is 355nm UV detection of atmospheric temperature, excitation wavelength is shorter, the backscatter differential cross section of the greater rotational Raman signal is strong, and 355nm is in the range of visible light during the day, easier to achieve detection. Simulation results show that the interference filter center wavelength high order rotational quantum number Raman channel is more sensitive to temperature detection accuracy. (4) Ji Guanglei The system was successfully developed in Hefei and Beijing regions to carry out observation and analysis of the near surface atmospheric temperature, the reliability of radiosonde verification instrument at the same time release. The observation data show that the tropospheric temperature has obvious spatial distribution characteristics. (5) this paper focuses on the analysis of measurement uncertainty and the effects of different spatial and temporal resolution and calibration constant on temperature detection accuracy. The cumulative pulse number, the smaller the noise signal-to-noise ratio is larger, the uncertainty of the measurement signal is small. The cumulative excitation pulse number is 10000 (5000), corresponding to 30m, 60m, 120m and 240m spatial resolution, near at the height of 8km to ground temperature measurement uncertainty values are 1.09K (1.33K), 0.83K (0.85K), 0.78K (0.79K) and 0.88K (0.89K). The calibration constants A and B not only affects the temperature profile of the horizontal movement, but also on the temperature profile shapes Affect the translation calibration constants of C only affects the temperature profile. According to the observation data shows that a and C have the same trend, the change trend of B was opposite. When a, B and C in the same trend, using the formula of temperature inversion error caused by errors tend to cancel one another; when a, C the changes of B and the opposite trend, using the formula of temperature inversion error is large.

【學位授予單位】:中國科學技術(shù)大學
【學位級別】:博士
【學位授予年份】:2017
【分類號】:TN958.98

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相關(guān)期刊論文 前10條

1 傅曉云;高則尚;李寶仁;;大氣溫度模擬系統(tǒng)研究[J];機床與液壓;2008年10期

2 王剛,王仕t,

本文編號:1568036


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