本文選題：MST雷達(dá) + 大氣參數(shù)反演　； 參考：《武漢大學(xué)》2016年博士論文

【摘要】：MST (Mesosphere-Stratosphere-Troposphere)雷達(dá)基于晴空湍流散射原理,用以觀測(cè)中間層、平流層和對(duì)流層大氣三維運(yùn)動(dòng)狀態(tài),主要獲取相應(yīng)高度區(qū)間的大氣三維風(fēng)廓線和湍流特性參數(shù)。武漢MST雷達(dá)作為中國(guó)大陸首批建設(shè)MST雷達(dá),坐落于湖北省崇陽(yáng)縣(地理坐標(biāo)：11408'8''E,29°31'58”N；地磁緯度約為：19.56°)。MST雷達(dá)的建成對(duì)于深入研究中高層大氣風(fēng)場(chǎng)的空間結(jié)構(gòu)和時(shí)間變化、辯明中高層大氣中關(guān)鍵的動(dòng)力學(xué)過(guò)程、弄清中高層大氣與電離層及低層大氣的耦合機(jī)制、建立我國(guó)上空中高層大氣的風(fēng)場(chǎng)模式、提供空間環(huán)境監(jiān)測(cè)和預(yù)報(bào)服務(wù)等具有重要的科學(xué)意義和工程應(yīng)用價(jià)值。本文主要基于武漢MST雷達(dá)多年的觀測(cè)數(shù)據(jù),對(duì)其應(yīng)用技術(shù)開展研究。本文的主要工作和研究特色、創(chuàng)新點(diǎn)如下：1、利用MST雷達(dá)垂直風(fēng)速的變化計(jì)算B-V (Brunt-Vaisala)頻率,再根據(jù)B-V頻率和溫度的關(guān)系,建立了離散的溫度反演模型。然后結(jié)合地面大氣溫度和中性大氣參考模型可以反演得到大氣溫度剖面,通過(guò)與探空儀實(shí)測(cè)溫度剖面比較,二者的吻合度非常高,變化趨勢(shì)也完全一致。同時(shí)計(jì)算表明在對(duì)流層和平流層B-V頻率的平均值有很大的差異,而B-V頻率的跳變值則是對(duì)流層頂高度的位置。2、為了更加方便地判斷對(duì)流層頂高度,并且分析對(duì)流層頂結(jié)構(gòu)形態(tài)的變化,根據(jù)對(duì)武漢MST雷達(dá)和北京MST雷達(dá)兩個(gè)地區(qū)的對(duì)流層頂探測(cè)數(shù)據(jù)的統(tǒng)計(jì)分析,考慮到對(duì)流層頂可能會(huì)發(fā)生傾斜,本文建立了更加普適的雷達(dá)對(duì)流層頂模型。通過(guò)與實(shí)測(cè)溫度剖面對(duì)比分析,發(fā)現(xiàn)氣象對(duì)流層頂比雷達(dá)對(duì)流層頂約高2 km。利用本文模型計(jì)算的對(duì)流層頂相對(duì)回波的強(qiáng)弱,可以反映了對(duì)流層頂雷達(dá)回波的空間方向敏感性,對(duì)于理解對(duì)流層頂?shù)男纬珊拖?以及層結(jié)的疏密結(jié)構(gòu)非常有幫助。利用武漢和北京兩部MST雷達(dá)2012年的對(duì)流層頂觀測(cè)數(shù)進(jìn)行據(jù)統(tǒng)計(jì)分析,結(jié)果表明：1)崇陽(yáng)地區(qū)對(duì)流層頂?shù)钠骄叨缺认愫拥貐^(qū)對(duì)流層頂平均高度高約1 km,這是因?yàn)橄愫拥牡乩砭暥缺瘸珀?yáng)的高,體現(xiàn)了對(duì)流層頂高度隨著緯度增加而降低的特性；2)崇陽(yáng)地區(qū)對(duì)流層頂?shù)南鄬?duì)回波強(qiáng)度比香河地區(qū)對(duì)流層頂相對(duì)回波強(qiáng)約4dB,說(shuō)明在緯度較高的地區(qū)對(duì)流層頂?shù)慕Y(jié)構(gòu)稀疏,對(duì)流層頂雷達(dá)回波的方向依賴性較弱；3)崇陽(yáng)和北京地區(qū)對(duì)流層頂?shù)母叨群拖鄬?duì)回波強(qiáng)度的標(biāo)準(zhǔn)差都非常接近,說(shuō)明對(duì)流層頂高度變化及結(jié)構(gòu)形態(tài)相對(duì)差異在各個(gè)地區(qū)是基本一致的。通過(guò)對(duì)模型計(jì)算的相對(duì)回波數(shù)據(jù)的周期譜分析,可以發(fā)現(xiàn)雷達(dá)對(duì)流層頂相對(duì)回波同時(shí)受潮汐波和行星波的調(diào)制,即潮汐波和行星波會(huì)影響對(duì)流層頂?shù)男纬珊徒Y(jié)構(gòu)形態(tài)。3、通過(guò)折射率理論研究和模型仿真表明,對(duì)于波長(zhǎng)為6m(武漢MST雷達(dá)波長(zhǎng)為5.58 m)左右的電磁波而言,降雨粒子和大氣湍流具有幾乎等數(shù)量級(jí)的反射率,由此可以推斷武漢MST雷達(dá)能夠同時(shí)明顯地觀測(cè)到大氣湍流回波和降雨粒子回波�；诮涤炅Ｗ踊夭ê痛髿馔牧骰夭ǖ淖V特征,本文建立了相應(yīng)的頻譜分離模型,分別了計(jì)算降雨環(huán)境中的雨滴運(yùn)動(dòng)參數(shù)和背景大氣運(yùn)動(dòng)狀態(tài)。利用武漢MST雷達(dá)分別對(duì)崇陽(yáng)地區(qū)大氣層狀降雨和大氣強(qiáng)對(duì)流降雨進(jìn)行了觀測(cè),分別研究了不同降雨類型下大氣降雨粒子回波的特性、雨滴的運(yùn)動(dòng)狀態(tài)以及背景大氣三維風(fēng)場(chǎng)的變化。結(jié)果表明：1)降雨粒子回波譜比大氣湍流譜的譜寬更寬,可以明顯地區(qū)分大氣融解層和雨滴下墜區(qū)域；2)層狀降雨回波一般出現(xiàn)在零度等溫線以下,而強(qiáng)對(duì)流降雨回波則會(huì)出現(xiàn)在零度等溫線以上；3)強(qiáng)對(duì)流降雨的背景風(fēng)場(chǎng)非常紊亂,降雨持續(xù)時(shí)間較短；4)利用層狀降雨粒子回波可以分析亮帶及融解層特性,可以反演不同高度的雨滴粒徑分布。此外,局部強(qiáng)對(duì)流天氣使得雷達(dá)不同方向波束觀測(cè)到的大氣運(yùn)動(dòng)狀態(tài)完全不同,因此在強(qiáng)對(duì)流天氣下很難得到雷達(dá)波束掃描空間內(nèi)的大氣平均運(yùn)動(dòng)狀態(tài),這對(duì)波束掃描合成大氣三維風(fēng)場(chǎng)帶來(lái)了挑戰(zhàn)。本文結(jié)合強(qiáng)對(duì)流天氣武漢MST雷達(dá)波束掃描觀測(cè)實(shí)例,詳細(xì)地分析了強(qiáng)對(duì)流天氣下雷達(dá)水平風(fēng)的測(cè)量困境,并給出相關(guān)探測(cè)建議。4、基于準(zhǔn)單色重力波模型,利用武漢MST雷達(dá)觀測(cè)數(shù)據(jù)對(duì)低平流層和對(duì)流層大氣慣性重力波進(jìn)行了討論分析,并對(duì)強(qiáng)對(duì)流和對(duì)流層頂急流激發(fā)的重力波傳播特性進(jìn)行了事例分析。利用武漢MST雷達(dá)兩年多的觀測(cè)數(shù)據(jù)分別對(duì)上行和下行重力波的特征頻率,垂直波長(zhǎng)、水平波長(zhǎng)、譜斜率和峰值能量密度等大氣慣性重力波參數(shù)進(jìn)行了統(tǒng)計(jì)分析,可以為構(gòu)建局部大氣重力波參考模型提供技術(shù)參數(shù)。此外,利用Lomb-Scargle周期譜分析方法對(duì)2012年全年武漢MST雷達(dá)觀測(cè)的對(duì)流層和低平流層的經(jīng)向風(fēng)和緯向風(fēng)進(jìn)行了季節(jié)潮汐波和行星波檢測(cè)分析,結(jié)果表明：1)各個(gè)季節(jié)的周日潮分量都相對(duì)較強(qiáng),小周期潮汐分量非常弱,潮汐波的振幅具有明顯的周期性變化；2)潮汐波的振幅會(huì)受到比其時(shí)間尺度更長(zhǎng)的潮汐波和行星際波的共同調(diào)制,但是比其時(shí)間尺度小的波基本不足以影響它；3)在下對(duì)流層高度區(qū)間主要是以相對(duì)較短的時(shí)間尺度行星波存在,而在上對(duì)流層和低平流層高度區(qū)間則是以相對(duì)較長(zhǎng)的時(shí)間尺度的行星波存在。5、利用武漢MST雷達(dá)數(shù)字波束合成技術(shù),分析了不同傾角下不同波束在不同高度范圍內(nèi)的回波特性,計(jì)算了不同高度雷達(dá)回波的方向敏感性,即大氣角譜,研究不同高度雷達(dá)回波的物理機(jī)制,結(jié)果表明：1)在對(duì)流層小傾角空問(wèn)內(nèi),雷達(dá)回波主要是部分反射和各向異性湍流散射為主,在相對(duì)高傾角則是各向異性和各向同性湍流共同散射作用；2)高度越高和傾角越大,雷達(dá)回波中各向同性湍流散射的貢獻(xiàn)越大,在中間層和低熱層雷達(dá)回波主要以各向同性散射為主；3)大氣穩(wěn)定層結(jié)的雷達(dá)回波方向敏感性參數(shù)相對(duì)較小,主要是因?yàn)檫@些穩(wěn)定層結(jié)大氣結(jié)構(gòu)相對(duì)密實(shí),對(duì)雷達(dá)回波有很好的部分反射作用,但是通過(guò)改變傾角可以發(fā)現(xiàn),這些大氣穩(wěn)定層結(jié)隨著波束傾角增大并非一直存在,而是具有一定的水平尺度。6、雷達(dá)對(duì)稱波束的回波差異表明了大氣層的傾斜狀態(tài),當(dāng)對(duì)稱波束中有一個(gè)方向的回波明顯高于另一個(gè)方向時(shí),則大氣層表現(xiàn)為向回波強(qiáng)的方向傾斜；傾斜的角度,則需要在同一個(gè)方向通過(guò)變化傾角連續(xù)掃描,回波最強(qiáng)的傾角對(duì)應(yīng)大氣層傾斜的角度。為了研究大氣層傾斜的影響因素,本文對(duì)不同高度的對(duì)稱波束回波差進(jìn)行了周期檢測(cè),結(jié)果表明：1)在對(duì)流層區(qū)域,各種尺度的波動(dòng)(重力波、潮汐波和行星波等)幾乎都能對(duì)大氣層結(jié)構(gòu)產(chǎn)生一定的影響；2)在低平流層,行星波的影響基本很弱,同時(shí)小尺度的重力波的影響也相對(duì)較弱,8小時(shí)潮、12小時(shí)潮和24小時(shí)潮分量相對(duì)較強(qiáng)；3)在中間層和低熱層區(qū)域,雷達(dá)對(duì)稱波束回波功率差的擾動(dòng)周期分量基本全是潮汐波分量,而且24小時(shí)潮的周期譜最寬,說(shuō)明24小時(shí)潮的脈動(dòng)最強(qiáng),由此可見在中間層和低熱層區(qū)域潮汐波是導(dǎo)致大氣層結(jié)構(gòu)發(fā)生傾斜的主要因素。
[Abstract]:The MST ( MST ) radar is based on the principle of clear air turbulence scattering , which is used to observe the three - dimensional motion state of the middle layer , the drift layer and the counter - flow layer . The three - dimensional wind profile and the turbulence characteristic parameters of the atmospheric three - dimensional wind profile and the turbulence characteristic parameters are obtained . The Wuhan MST radar is used as the first construction MST radar in the mainland of China , and is located in Chongyang County , Hubei Province ( geographic coordinates : 11408 ' 8 ' E , 29 擄 31 ' 58 " N ;
The geomagnetic latitude is about 19.56 擄 . This paper studies the spatial structure and temporal change of the upper atmosphere wind field in the middle and high - rise atmosphere , and the key dynamic process in the middle and high - rise atmosphere is studied .
2 ) The relative echo intensity of the convective layer top in Chongyang area is about 4dB stronger than that of the convective layer in the Xianghe area , which indicates that the structure of the convective layer top is sparse in the area with higher latitude , and the directional dependence of the echo of the top radar is weaker ;
Based on the periodic analysis of the relative echo data of the model , it can be found that the relative echo of the top of the radar can be modulated by tidal wave and planetary wave .
2 ) Layered rainfall echo generally occurs below zero degree isotherm , while strong convective rainfall echo will appear above zero degree isotherm ;
3 ) the background wind field of strong convection rainfall is very disordered and the rainfall duration is short ;
Based on quasi - monochromatic gravity wave model , the atmospheric inertia gravity waves of the upper and lower layers of the radar beam are analyzed by means of the observation data of Wuhan MST radar . The results show that : 1 ) The diurnal tidal components of the upper and lower flow layers are relatively strong and the tidal component of the small period is very weak , and the amplitude of tidal wave has obvious periodic variation .
2 ) The amplitude of tidal wave will be co - modulated by tide wave and intergalactic wave longer than its time scale , but the wave whose time scale is smaller than its time scale is not enough to affect it ;
In this paper , the echo characteristics of different wave beams at different altitudes are analyzed by using the technique of digital beam synthesis in Wuhan MST radar . The physical mechanism of different altitude radar echoes is analyzed . The results show that : 1 ) In the small dip angle of the counter flow , the radar echo is mainly part reflection and anisotropic turbulent scattering , and the relative high inclination is the co - scattering of anisotropic and isotropic turbulence .
2 ) The higher the height and the greater the inclination angle , the larger the contribution of isotropic turbulence scattering in the radar echo , the larger the isotropic scattering in the middle layer and the low - heat - layer radar echo ;
3 ) The sensitivity parameters of the radar echo direction of the atmospheric stable layer junction are relatively small , mainly because of the relatively compact structure of these stable layers , which has a good partial reflection effect on the radar echo . However , by changing the inclination angle , it can be found that these atmospheric stable layers are not always present along with the increase of the beam tilt angle , but have a certain horizontal dimension .
In order to study the influence factors of the atmospheric tilt , this paper makes periodic detection of the difference of symmetric beam echo in different heights . The results show that : 1 ) In the region of the Troposphere , the fluctuation of various scales ( gravitational waves , tidal waves and planetary waves ) can exert a certain influence on the structure of the atmosphere ;
2 ) At the low level , the influence of the planetary wave is very weak , and the influence of the small scale gravity wave is relatively weak , the 8 - hour tide , the 12 - hour tide and the 24 - hour tide component are relatively strong ;
3 ) In the middle layer and the low heat layer area , the disturbance period component of the radar symmetric beam echo power difference is basically the tidal wave component , and the periodic spectrum of the 24 hours tide is the widest , which shows that the pulsation of the 24 hours tide is strongest , thus the tidal wave in the middle layer and the low heat layer region is the main factor leading to the inclination of the atmosphere structure .

【學(xué)位授予單位】：武漢大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：P412.25
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本文編號(hào)：1772574