本文主要研究内容
作者谭子渊（2019）在《中国西北干旱半干旱区边界层高度特征及其对沙尘天气影响的数值模拟研究》一文中研究指出：大气边界层是地表与大气之间进行物质和能量交换的重要媒介,一些灾害性天气现象的形成大多与边界层过程密切相关。沙尘天气作为一种与边界层密切相关的灾害性天气,对人民生活生产及生态环境造成重大影响。中国西北干旱半干旱区因其特殊的地理位置和气候条件,成为我国沙尘天气多发地之一,并且有独特的大气边界层特征,研究该区域边界层高度特征及其对沙尘天气的影响,为探索沙尘天气形成机理及预警、防灾减灾具有十分重要的意义。首先,本文采用ERA-Interim再分析资料和WRF模式研究了中国西北干旱半干旱区边界层高度时空分布特征及深厚边界层模拟的参数化方案最优组合;其次,分析了5个代表地区沙尘天气时空分布及沙尘天气条件下边界层高度变化特征;使用多种气象数据分析了中国西北一次典型沙尘天气的成因及其影响;最后,利用WRF-Chem模式模拟了上述沙尘天气个例的起沙传输过程、边界层高度特征,以及地表热通量对边界层高度的影响及其伴随的沙尘垂直分布变化,主要得到以下结论:(1)5个代表地区边界层高度14时为春末及夏季较高(6月最高达2485m~3502m),秋冬及初春较低(12月最低为758m~907m);02时和08时边界层高度季节变化幅度相对较小,而14时和20时变化幅度较大;边界层高度超过4000米的情况主要出现在夏季和春末。春夏秋14时和20时边界层高度干旱代表地区敦煌和民勤大于半干旱代表地区兰州和榆中;地区间差异夏季较大,冬季较小。夏季干旱区白天深厚大气边界层高度持续时间较长,高度大于2000m的大气边界层在极端干旱区敦煌5-8月平均持续时间超过6h,而酒泉和民勤仅6-7月份较高大气边界层持续6h以上。(2)数值模拟结果表明,不同参数化方案组合对不同地区深厚边界层的模拟差异显著,与边界层发展相对紧密的三类参数化方案中,短波辐射、陆面过程和边界层方案的选取对边界层高度数值模拟结果的影响程度不同,对敦煌、民勤、榆中和兰州深厚边界层模拟结果影响从大到小依次是边界层方案、陆面过程方案、短波辐射方案,而酒泉是边界层方案、短波辐射方案、陆面过程方案;极端干旱区敦煌和干旱区酒泉、民勤Goddard+SLAB+ACM2组合模拟效果较好,半干旱区榆中和兰州Dudhia+Noah+ACM2方案表现较好。模拟效果的差异与边界层方案确定边界层高度的方法、陆面过程方案对下垫面性质的考虑、短波辐射方案关于吸收物质对短波辐射吸收的处理有关。(3)敦煌、酒泉和民勤沙尘天气年际分布呈减少的趋势,榆中和兰州呈波动变化,其中敦煌出现沙尘天气次数最多,年均34次;敦煌和酒泉以浮尘和扬沙为主,民勤以扬沙和沙尘暴为主,榆中和兰州以浮尘为主。各地沙尘天气均主要出现在2~5月,春季沙尘天气次数占全年沙尘天气次数的50%以上,秋季在10%以下;各时次分布特征上,浮尘总体差异不大,扬沙和沙尘暴主要集中在下午及傍晚。敦煌和民勤夜间沙尘天气边界层高度明显高于晴天,且沙尘天气强度越强,边界层高度越高;白天强沙尘天气边界层高度高于浮尘。典型沙尘个例(2017年1月24~26日)是在高空槽东移发展,冷空气南下,配合地面高压系统和锋面东移,冷锋后强气压梯度形成大风的条件下形成;HYSPLIT模式模拟结果显示沙尘沿西北路径传输,沙尘源地位于甘肃以西,沿河西走廊向东南传输至陇中地区;沙尘天气发生前沙尘源地气温上升造成土壤湿度下降,低层大气处于不稳定状态,有利于起沙,沙尘天气期间各层较大的水平风速有利于沙尘的水平输送,垂直方向上沙尘源地和民勤中低层皆有上升运动,将沙尘粒子带入高空,传输路径上的其他代表地区为下沉运动,将高空的沙尘带到近地面形成沙尘天气。沙尘天气期间沙尘源地和民勤白天边界层高度较前一日有所上升,而酒泉、张掖白天边界层高度较前一日有所下降,兰州和榆中夜间边界层则有所升高。(4)沙尘源地和民勤在沙尘天气过程中地面垂直起沙通量和10 m风速均较大,源地中心区域地面垂直起沙通量达3000μg/m~2/s以上,10 m风速达20 m/s。控制实验中沙尘源地沙尘浓度高值区可至离地1000 m以上,浓度达24000μg/m~3以上,并且强烈的上升运动可使沙尘传输至离地3000 m以上;民勤沙尘浓度高值区始终维持在离地1000 m以上。起沙阶段,沙尘源地地面沙尘浓度高值区边界层高度大于周围地区,且大于该地对应时刻的平均边界层高度。敏感性实验表明关闭地面热通量后沙尘区范围明显减小,地面沙尘浓度大大降低,两者浓度差最大可达4倍以上;敏感性实验中沙尘浓度高值区附近边界层高度明显小于控制实验,但当沙尘浓度升高到一定程度后,二者的边界层高度差距减小;与控制实验不同,敏感性实验中沙尘浓度高值区与其周边地区的边界层高度差异相对较小,分布相对均一。垂直方向上敏感性试验中沙尘源地起沙阶段沙尘浓度高值区始终保持在离地400 m以下,民勤两组实验沙尘浓度高值中心也相差500 m左右;边界层高度对沙尘的垂直分布有显著的影响,边界层高度越高,越有利于沙尘向上扩散,而沙尘浓度对边界层高度也有影响。
Abstract
da qi bian jie ceng shi de biao yu da qi zhi jian jin hang wu zhi he neng liang jiao huan de chong yao mei jie ,yi xie zai hai xing tian qi xian xiang de xing cheng da duo yu bian jie ceng guo cheng mi qie xiang guan 。sha chen tian qi zuo wei yi chong yu bian jie ceng mi qie xiang guan de zai hai xing tian qi ,dui ren min sheng huo sheng chan ji sheng tai huan jing zao cheng chong da ying xiang 。zhong guo xi bei gan han ban gan han ou yin ji te shu de de li wei zhi he qi hou tiao jian ,cheng wei wo guo sha chen tian qi duo fa de zhi yi ,bing ju you du te de da qi bian jie ceng te zheng ,yan jiu gai ou yu bian jie ceng gao du te zheng ji ji dui sha chen tian qi de ying xiang ,wei tan suo sha chen tian qi xing cheng ji li ji yu jing 、fang zai jian zai ju you shi fen chong yao de yi yi 。shou xian ,ben wen cai yong ERA-Interimzai fen xi zi liao he WRFmo shi yan jiu le zhong guo xi bei gan han ban gan han ou bian jie ceng gao du shi kong fen bu te zheng ji shen hou bian jie ceng mo ni de can shu hua fang an zui you zu ge ;ji ci ,fen xi le 5ge dai biao de ou sha chen tian qi shi kong fen bu ji sha chen tian qi tiao jian xia bian jie ceng gao du bian hua te zheng ;shi yong duo chong qi xiang shu ju fen xi le zhong guo xi bei yi ci dian xing sha chen tian qi de cheng yin ji ji ying xiang ;zui hou ,li yong WRF-Chemmo shi mo ni le shang shu sha chen tian qi ge li de qi sha chuan shu guo cheng 、bian jie ceng gao du te zheng ,yi ji de biao re tong liang dui bian jie ceng gao du de ying xiang ji ji ban sui de sha chen chui zhi fen bu bian hua ,zhu yao de dao yi xia jie lun :(1)5ge dai biao de ou bian jie ceng gao du 14shi wei chun mo ji xia ji jiao gao (6yue zui gao da 2485m~3502m),qiu dong ji chu chun jiao di (12yue zui di wei 758m~907m);02shi he 08shi bian jie ceng gao du ji jie bian hua fu du xiang dui jiao xiao ,er 14shi he 20shi bian hua fu du jiao da ;bian jie ceng gao du chao guo 4000mi de qing kuang zhu yao chu xian zai xia ji he chun mo 。chun xia qiu 14shi he 20shi bian jie ceng gao du gan han dai biao de ou dui huang he min qin da yu ban gan han dai biao de ou lan zhou he yu zhong ;de ou jian cha yi xia ji jiao da ,dong ji jiao xiao 。xia ji gan han ou bai tian shen hou da qi bian jie ceng gao du chi xu shi jian jiao chang ,gao du da yu 2000mde da qi bian jie ceng zai ji duan gan han ou dui huang 5-8yue ping jun chi xu shi jian chao guo 6h,er jiu quan he min qin jin 6-7yue fen jiao gao da qi bian jie ceng chi xu 6hyi shang 。(2)shu zhi mo ni jie guo biao ming ,bu tong can shu hua fang an zu ge dui bu tong de ou shen hou bian jie ceng de mo ni cha yi xian zhe ,yu bian jie ceng fa zhan xiang dui jin mi de san lei can shu hua fang an zhong ,duan bo fu she 、liu mian guo cheng he bian jie ceng fang an de shua qu dui bian jie ceng gao du shu zhi mo ni jie guo de ying xiang cheng du bu tong ,dui dui huang 、min qin 、yu zhong he lan zhou shen hou bian jie ceng mo ni jie guo ying xiang cong da dao xiao yi ci shi bian jie ceng fang an 、liu mian guo cheng fang an 、duan bo fu she fang an ,er jiu quan shi bian jie ceng fang an 、duan bo fu she fang an 、liu mian guo cheng fang an ;ji duan gan han ou dui huang he gan han ou jiu quan 、min qin Goddard+SLAB+ACM2zu ge mo ni xiao guo jiao hao ,ban gan han ou yu zhong he lan zhou Dudhia+Noah+ACM2fang an biao xian jiao hao 。mo ni xiao guo de cha yi yu bian jie ceng fang an que ding bian jie ceng gao du de fang fa 、liu mian guo cheng fang an dui xia dian mian xing zhi de kao lv 、duan bo fu she fang an guan yu xi shou wu zhi dui duan bo fu she xi shou de chu li you guan 。(3)dui huang 、jiu quan he min qin sha chen tian qi nian ji fen bu cheng jian shao de qu shi ,yu zhong he lan zhou cheng bo dong bian hua ,ji zhong dui huang chu xian sha chen tian qi ci shu zui duo ,nian jun 34ci ;dui huang he jiu quan yi fu chen he yang sha wei zhu ,min qin yi yang sha he sha chen bao wei zhu ,yu zhong he lan zhou yi fu chen wei zhu 。ge de sha chen tian qi jun zhu yao chu xian zai 2~5yue ,chun ji sha chen tian qi ci shu zhan quan nian sha chen tian qi ci shu de 50%yi shang ,qiu ji zai 10%yi xia ;ge shi ci fen bu te zheng shang ,fu chen zong ti cha yi bu da ,yang sha he sha chen bao zhu yao ji zhong zai xia wu ji bang wan 。dui huang he min qin ye jian sha chen tian qi bian jie ceng gao du ming xian gao yu qing tian ,ju sha chen tian qi jiang du yue jiang ,bian jie ceng gao du yue gao ;bai tian jiang sha chen tian qi bian jie ceng gao du gao yu fu chen 。dian xing sha chen ge li (2017nian 1yue 24~26ri )shi zai gao kong cao dong yi fa zhan ,leng kong qi na xia ,pei ge de mian gao ya ji tong he feng mian dong yi ,leng feng hou jiang qi ya ti du xing cheng da feng de tiao jian xia xing cheng ;HYSPLITmo shi mo ni jie guo xian shi sha chen yan xi bei lu jing chuan shu ,sha chen yuan de wei yu gan su yi xi ,yan he xi zou lang xiang dong na chuan shu zhi long zhong de ou ;sha chen tian qi fa sheng qian sha chen yuan de qi wen shang sheng zao cheng tu rang shi du xia jiang ,di ceng da qi chu yu bu wen ding zhuang tai ,you li yu qi sha ,sha chen tian qi ji jian ge ceng jiao da de shui ping feng su you li yu sha chen de shui ping shu song ,chui zhi fang xiang shang sha chen yuan de he min qin zhong di ceng jie you shang sheng yun dong ,jiang sha chen li zi dai ru gao kong ,chuan shu lu jing shang de ji ta dai biao de ou wei xia chen yun dong ,jiang gao kong de sha chen dai dao jin de mian xing cheng sha chen tian qi 。sha chen tian qi ji jian sha chen yuan de he min qin bai tian bian jie ceng gao du jiao qian yi ri you suo shang sheng ,er jiu quan 、zhang ye bai tian bian jie ceng gao du jiao qian yi ri you suo xia jiang ,lan zhou he yu zhong ye jian bian jie ceng ze you suo sheng gao 。(4)sha chen yuan de he min qin zai sha chen tian qi guo cheng zhong de mian chui zhi qi sha tong liang he 10 mfeng su jun jiao da ,yuan de zhong xin ou yu de mian chui zhi qi sha tong liang da 3000μg/m~2/syi shang ,10 mfeng su da 20 m/s。kong zhi shi yan zhong sha chen yuan de sha chen nong du gao zhi ou ke zhi li de 1000 myi shang ,nong du da 24000μg/m~3yi shang ,bing ju jiang lie de shang sheng yun dong ke shi sha chen chuan shu zhi li de 3000 myi shang ;min qin sha chen nong du gao zhi ou shi zhong wei chi zai li de 1000 myi shang 。qi sha jie duan ,sha chen yuan de de mian sha chen nong du gao zhi ou bian jie ceng gao du da yu zhou wei de ou ,ju da yu gai de dui ying shi ke de ping jun bian jie ceng gao du 。min gan xing shi yan biao ming guan bi de mian re tong liang hou sha chen ou fan wei ming xian jian xiao ,de mian sha chen nong du da da jiang di ,liang zhe nong du cha zui da ke da 4bei yi shang ;min gan xing shi yan zhong sha chen nong du gao zhi ou fu jin bian jie ceng gao du ming xian xiao yu kong zhi shi yan ,dan dang sha chen nong du sheng gao dao yi ding cheng du hou ,er zhe de bian jie ceng gao du cha ju jian xiao ;yu kong zhi shi yan bu tong ,min gan xing shi yan zhong sha chen nong du gao zhi ou yu ji zhou bian de ou de bian jie ceng gao du cha yi xiang dui jiao xiao ,fen bu xiang dui jun yi 。chui zhi fang xiang shang min gan xing shi yan zhong sha chen yuan de qi sha jie duan sha chen nong du gao zhi ou shi zhong bao chi zai li de 400 myi xia ,min qin liang zu shi yan sha chen nong du gao zhi zhong xin ye xiang cha 500 mzuo you ;bian jie ceng gao du dui sha chen de chui zhi fen bu you xian zhe de ying xiang ,bian jie ceng gao du yue gao ,yue you li yu sha chen xiang shang kuo san ,er sha chen nong du dui bian jie ceng gao du ye you ying xiang 。
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论文作者分别是来自兰州大学的谭子渊，发表于刊物兰州大学2019-07-29论文，是一篇关于沙尘天气论文,边界层高度论文,时空分布论文,数值模拟论文,参数化方案论文,中国西北论文,兰州大学2019-07-29论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自兰州大学2019-07-29论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。
标签：沙尘天气论文; 边界层高度论文; 时空分布论文; 数值模拟论文; 参数化方案论文; 中国西北论文; 兰州大学2019-07-29论文;