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1.
甘肃民勤2001-2010年沙尘暴变化特征及原因分析 总被引：3，自引：0，他引：3
根据2001-2010年民勤沙尘暴资料和《中国沙尘天气年鉴》资料,分析了民勤近10年沙尘暴特征.结果表明:近10年民勤以局地性沙尘暴为主;一日中区域性沙尘暴较局地性沙尘暴出现分散且早,区域性沙尘暴4月出现最多,而局地性沙尘暴6月出现最多,区域性沙尘暴春季出现最多,而局地性沙尘暴春季最多,夏季和春季相当,年际均呈现明显减少的趋势;从逐年强沙尘暴次数、平均持续时间、造成的损失等分析,认为沙尘暴强度没有减弱,强沙尘暴强度变化不大.用1971-2010年常规气象观测资料和典型沙尘暴个例探空气象资料分析沙尘暴减少的原因为:一是大风日数减少、平均风速减小;二是当地植被覆盖率逐年提高;三是近地层多暖平流、冷空气活动减弱. 相似文献
2.
中国50a来沙尘暴变化特征 总被引：15，自引：11，他引：4
基于"中国强沙尘暴序列及其支撑数据集",对中国50a(1958—2007年)来沙尘暴时间和区域变化进行分析,揭示了中国沙尘暴时间和区域变化特征。结果表明,中国沙尘暴站时变化总体呈明显振动减少趋势,经历了两次迅速减少、两次大幅震动和两次和缓减少6个时期,每个时期约为8a,1983—2007年平均值比1958—1982年平均值减少58.4%。沙尘暴的站次平均持续时间年际变化不大,季节变化相差1倍以上,频发日期有延迟趋势,后25a比前25a平均延迟了7d左右。沙尘暴的区域分布呈现两多、两少和两个中心的分布特征,时间变化特征区域表现差异大,新疆南部和内蒙古中西部两个频发中心春季的沙尘暴强度和范围呈相反顺序演变,新疆沙尘暴6月频发。在总体站时减少的情况下,浑善达克沙地西北部和柴达木盆地西北部地区却有增加趋势。沙尘暴终止的年份线向北推移明显,在90°E以东的地区北移,最为明显的华北地区北移大约5个纬度,其范围的缩小和频次的减少共同决定了总体站时减少。 相似文献
3.
《干旱区地理》2021,44(5):1339-1349
河西走廊中东部是我国春季沙尘暴的高发区和重灾区,近40 a来共造成经济损失超15×108元,近百人死亡。该区春季沙尘暴具有明显的日变化,为了深入分析其时间变化规律,提高预报预警能力,利用该区3个代表站1961—2019年沙尘暴地面观测资料及2019年5月2次沙尘暴过程的气象资料,采用天气学、动力学和统计学相结合的方法,得出该区春季沙尘暴的昼夜时间变化特征和预报着眼点。结果表明:(1)河西走廊中东部春季沙尘暴日数近60 a呈减少趋势,20世纪80年代显著减少;各站不同强度沙尘暴昼夜变化明显:白天多且风速较大,20世纪80年代后一般沙尘暴多于强沙尘暴,高发区均在民勤。(2)沙尘暴过境时各站盛行风向昼夜一致,集中在西北风到偏北风之间;强沙尘暴最强出现在00:00—01:00、18:00—19:00,一般沙尘暴最强出现在08:00—09:00。(3)进一步对2019年5月午后和夜间发生的2次沙尘暴过程进行对比分析:午后过程风力大、有灾情;夜间过程强度强、持续时间长。2次过程虽然中低层形势基本相同,沙尘暴出现在水平螺旋度负值中心下游及地气温差大值时,但高空500 hPa形势不同:午后过程为横槽转竖,气温日较差、风速日变化大,层结不稳定,有高空风动量下传,且近地面层最大风速出现高度低;夜间过程主要是不稳定低槽发展和蒙古气旋底部冷锋影响,配合强的垂直上升运动,但垂直风切变小。(4)河西走廊中东部春季沙尘暴不仅与大型的环流形势有关,还与垂直速度、水平螺旋度、全风速等物理量,以及地面温湿风日变化、不稳定参数和边界层要素有关。 相似文献
4.
西藏贡嘎沙尘天气气候及环流特征 总被引：1，自引：1，他引：0
利用1978-2012年西藏贡嘎的浮尘、扬沙和沙尘暴资料,分析了贡嘎沙尘天气的气候特征。结果表明:贡嘎沙尘天气冬、春季最多,秋季较少,夏季很少发生;扬沙和沙尘暴主要发生在午后,浮尘则全天均可发生;近35年来,扬沙和沙尘暴呈波动减少趋势,减少幅度分别约为7 d-10a和2.2 d-10a,浮尘约以0.5 d/10a的幅度呈不显著增加趋势;基于2005-2012年沙尘天气同期红外差值沙尘指数(IDDI)空间分布图和地面流场、沙地分布图,定性得出贡嘎、尼木、南木林、日喀则、拉孜区域的雅鲁藏布江沿岸沙地是贡嘎沙尘天气的沙尘来源。利用沙尘暴天气个例分析了贡嘎沙尘天气的地面气象要素和高空环流特征,发现相对湿度小、风速大、连续多日无降水是沙尘天气的地面气象要素特征,高空环流形势可分为阻塞型(占40%)、干南支槽型(占17%)、西北气流型(占26%)和热低压型(占17%)等4类。 相似文献
5.
6.
河北省坝上地区1971-2010年沙尘暴日数变化特征及与气象因素关系 总被引：1，自引：0，他引：1
利用1971-2010年地面气象观测资料,分析了坝上地区沙尘暴日数的季节变化和年变化特征及其与大风、降水、气温的关系。结果表明：坝上地区沙尘暴日数具有明显的季节性变化特征,春季沙尘暴日数最多,占全年沙尘暴日数的84.88%,秋季最少,仅占全年沙尘暴日数的1.39%,冬季沙尘暴日数多于夏季;从年变化特征上看,20世纪70年代沙尘暴发生日数最多,80年代减少,90年代达到最少,2000年后沙尘暴日数又开始增加,但总体来说沙尘暴日数呈现出波动中下降的趋势;年沙尘暴日数和年大风日数有显著的正相关,与前期、同期降水量没有达到显著相关,但是有着很好的对应关系,与年平均气温有显著的负相关。 相似文献
7.
2004年春夏季两次沙尘暴期间地面气象要素变化特征对比分析 总被引：5，自引：2，他引：3
用沙尘暴自动观测系统记录的每分钟地面气象要素,分析了2004年3月28日和7月12日发生在甘肃酒泉的两次沙尘暴过境时地面微气象要素的变化特征。结果表明：①两次沙尘暴发生前地面湿度都较小,气压较低,但是在临近发生时地面气压会猛增,接着维持一段时间的相对稳定状态,但春季沙尘暴过程这个时间更长;沙尘暴即将结束时地面气压再次大幅增加。②沙尘暴发生前气温偏高,结束后较短时间气温会出现急剧下降;春季沙尘暴期间0 cm地温和气温的变化趋势比较一致,但是5 cm地温的变化趋势与气温变化差别较大;夏季沙尘暴过程中0 cm、5 cm地温的变化趋势与气温变化趋势都比较一致。③由于下垫面性质的差异,春季发生的这次沙尘暴地面水平风速明显比同年夏季发生的沙尘暴大,但水平能见度却比夏季发生的沙尘暴好。 相似文献
8.
甘肃春季沙尘暴环流特征及其时间尺度诊断分析 总被引：16，自引：8，他引：8
根据43a甘肃春季沙尘暴日数距平序列选取了甘肃春季沙尘暴多发年和少发年。对甘肃春季沙尘暴多发年和少发年前期冬季(12月至翌年2月)和同期春季(3~5月)500hPa环流距平场合成结果表明, 前期冬季东亚大槽、同期春季蒙古气旋是影响沙尘暴发生多少的主要系统。西风指数和东亚北风指数计算结果表明, 沙尘暴多发年与少发年指数差异明显, 沙尘暴与冬季风联系紧密。甘肃春季沙尘暴小波变换分析, 清楚地反映沙尘暴不同频域的变化特征及其交替作用; 不同频域小波系数变化说明21世纪初沙尘暴将趋于增加。 相似文献
9.
宁夏春季典型沙尘暴年环流特征量分析 总被引：15，自引：9，他引：6
利用近1960-2000年宁夏春季沙尘暴发生次数及常规气象与环流特征量、海温等资料, 首先分析得出了宁夏近41a来沙尘暴发生频次的变化规律; 其次通过对宁夏典型沙尘暴多、少年气候特征对比分析, 发现沙尘暴多、少年前期气象要素及环流特征量存在明显差异: 沙尘暴少(多)发年前一年夏季及前一年夏季到当年春季累积降水量偏多(少); 冬春季冷空气活动次数偏少(多); 前期及同期北半球极涡面积偏小(大)、强度偏弱(强); 冬季东亚大槽位置偏东(西)、强度偏弱(强); 前一年春季北太平洋海温距平场表现为厄尔尼诺遥相关分布型(反厄尔尼诺遥相关分布型)。依据作用机理, 提出了在西北地区生态环境局部治理、整体恶化背景下, 宁夏春季沙尘暴发生频次减少, 主要是东亚环流调整、冬季风减弱所致, 同时还形成了宁夏春季沙尘暴短期气候趋势预测概念模型。 相似文献
10.
近60年来西南地区旱涝变化及极端和持续性特征认识 总被引：3，自引：1，他引：2
利用1953~2012年中国西南地区44个气象台站的逐日降水、温度资料,通过降水和潜在蒸发均一化旱涝指数,从旱涝的年代际、年际、季节内变化以及极端和持续性特征等方面进行了分析,结果表明：从旱涝的空间趋势变化来看,西南近60 a来秋季和年变化呈显著的一致变旱趋势,而春、夏、冬3季旱涝变化趋势表现出一定的区域性特征;从旱涝的时间演变来看,在温度与降水双重因子驱动下春、夏、秋、冬均表现为干旱化趋势,相比较秋季的干旱化程度最强,而春季的最弱,夏、冬两季相当,而全年的干旱程度比四季的程度更强;从极端旱涝的多时间尺度来看,在年代际和年际尺度上,极端洪涝发生频次逐渐减少,而极端干旱发生频次逐渐增多,从季节尺度看,春、冬两季极端干旱发生频次较多,而夏季最少,极端洪涝发生频次夏季最多,春季次之,秋季最少。从旱涝的持续性特征来看,持续性干旱事件的持续时间有增长趋势,发生频率有增多趋势,发生强度有增强趋势,并且主要发生在冬春两季,而持续性洪涝事件的持续时间、发生强度没明显变化趋势,发生频率有减少趋势,发生的季节也没明显差异。 相似文献
11.
京、津、冀区域群发性强沙尘暴分析 总被引：1，自引：2，他引：1
利用1954—2002年82个站的气象观测资料，探讨京、津、冀区域群发性强沙尘暴的认定标准，构建较完整的群发性强沙尘暴序列，并分析该地区群发性强沙尘暴的时空分布特征和气候变化趋势。近50a京、津、冀区域共出现了39例群发性强沙尘暴，河北省的冀西北高原区和石家庄、保定、衡水、沧州四市交接处饶阳一带是京、津、冀区域强沙尘暴天气的多发区。多发季节为3—5月，占全年总数的76．9％，其中4月份最多，占全年总数的51．3％。群发性强沙尘暴年代际变化呈现总体减少趋势，其发生次数、覆盖面积均是以20世纪90年代为最低值． 相似文献
12.
在干旱和半干旱地区,盐尘暴是一种常见的极端气象灾害。柴达木盆地频发的沙尘暴实质上就是盐尘暴。柴达木盆地盐尘暴已经对区域大气、土壤、植被、人类健康乃至全球气候变化都产生了不同程度的影响。由于柴达木盆地盐尘暴中可溶盐成分来源复杂,尽管目前对其形成过程和机制还缺乏深刻理解,但人类的资源开发活动对盐尘暴显然具有促进作用。有必要从系统的角度来考虑柴达木盆地盐尘暴对区域乃至全球的影响,这对于区域生态环境的正确评估和后期恢复治理具有重要意义。 相似文献
13.
中国东部夏季降水的年代际变化格局——观测与CESM控制试验模拟结果的对比 总被引：1，自引：0，他引：1
根据1961-2005年中国东部389站的夏季降水观测资料,以及通用地球系统模式（the community earth system model,CESM）在固定边界条件驱动下的650年控制试验模拟结果,采用经验正交函数分解和功率谱分析等方法,辨识了中国东部夏季降水年代际变化的主导格局。观测分析与CESM的控制试验模拟结果均表明：中国东部夏季降水年代际变化的主导空间型为“南北反相”（大致以淮河流域为界）和由南到北的多带相间分布（长江流域、东北同相但与华南、华北反相）格局。对比证明：在无任何外强迫变化下,CESM可模拟出观测到的1961-2005年中国东部夏季降水年代际变化的主导空间型和相应的时间位相转折特征。这为深入辨识区域降水年代际异常的主控因子,分析气候系统外强迫变化和内部变率对中国降水年代际变化的影响机制提供了重要依据。 相似文献
14.
Based on the available original dust storm records from 60 meteorological stations, we discussed the identification standard
of severe dust storms at a single station and constructed a quite complete time series of severe group dust storms in the
eastern part of Northwest China in 1954–2001. The result shows that there were 99 severe group dust storms in this region
in recent 48 years. The spatial distribution indicates that the Alax Plateau, most parts of the Ordos Plateau and most parts
of the Hexi Corridor are the main areas influenced by severe group dust storms. In addition, the season and the month with
the most frequent severe group dust storms are spring and April, accounting for 78.8% and 41.4% of the total events respectively.
During the past 48 years the lowest rate of severe group dust storms occurred in the 1990s. Compared with the other 4 decades,
on the average, the duration and the affected area of severe group dust storms are relatively short and small during the 1990s.
In 2000 and 2001, there were separately 4 severe group dust storms as the higher value after 1983 in the eastern part of Northwest
China. 相似文献
15.
Based on the available original dust storm records from 60 meteorological stations, we discussed the identification standard of severe dust storms at a single station and constructed a quite complete time series of severe group dust storms in the eastern part of Northwest China in 1954-2001. The result shows that there were 99 severe group dust storms in this region in recent 48 years. The spatial distribution indicates that the Alax Plateau, most parts of the Ordos Plateau and most parts of the Hexi Corridor are the main areas influenced by severe group dust storms. In addition, the season and the month with the most frequent severe group dust storms are spring and April, accounting for 78.8% and 41.4% of the total events respectively. During the past 48 years the lowest rate of severe group dust storms occurred in the 1990s. Compared with the other 4 decades, on the average, the duration and the affected area of severe group dust storms are relatively short and small during the 1990s. In 2000 and 2001, there were separately 4 severe group dust storms as the higher value after 1983 in the eastern part of Northwest China. 相似文献
16.
Dust/sand storms are common events in the arid and semi-arid regions of Central Asia. The region is characterized by strong winds, scarcity of vegetation cover, continental climate with long and dry summers, frequent soil and atmospheric droughts. Central Asian drylands, covered by a great variety of desert types, represent a powerful source of mineral and salt aerosols.The main objectives of this study are to monitor and assess the spatial and temporal distribution of dust storms over the Central Asian region during the last seven decades. The identified active source areas of dust storms are located mainly in the sandy deserts and other types of deserts where the sensitive ecosystems suffered from human impact. The main persistent sources of dust storms are located in the large “dust belt” that extends from west to east over the southern deserts, north of Caspian Sea deserts, south of Balkhash Lake, and Aral Sea region. The results of the analysis show a significant decrease in dust/sand storm frequency during the last decades and considerable changes in the active source areas. 相似文献
17.
新疆地区气候与环境变化对沙尘暴的影响研究 总被引：23，自引：25，他引：23
根据新疆地区50年来的气候变化以及人类活动的影响，阐述了新疆沙尘暴源区气候与荒漠环境变化。结果表明，新疆地区的气候由暖干向暖湿发展。自20世纪70年代中期以来，暖湿过程非常明显，特别是新疆南疆与北疆的气候变化特点和高山与盆地的气候变化差异以及湖泊其他水域面积的变化，都明显地反映了干旱区域气候变化的敏感性，并且也反映了新疆区域气候与中国中、东部气候变化的差异性。由于气候的波动和人类活动的干扰．使不同地区的荒漠环境受到不同程度影响。干旱地区的降水、大气湿度、下垫面状况等都直接影响着沙尘暴的发生和发展。沙尘暴的发生频率和强度与沙尘源区的状况及其气候与荒漠环境变化以及动力条件(即天气系统)等具有密切的关系。因此，20世纪80年代后期以来，气候变暖是造成干旱区生态环境恶化、自然灾害尤其是风沙灾害和沙尘暴增多的主要原因之一。同时，也反映出内陆干旱区是气候变化的敏感反应区。 相似文献
18.
Although dust storms rarely occur in southern California's deserts, blowing dust often reduces visibility, and large spatial and temporal variability in the frequency of blowing dust occurs throughout the region. On average only 1.3 dust storms occur in the study area each year. The annual average number of dust events (visibility <11 km) is 18.0, with the Coachella Valley being dustiest region, averaging 37.8 dust events each year. Mean annual frequencies of dust events for 1973–1994 are mapped, showing a core of activity centered over the Imperial/Coachella Valley region, with fewer dust events around the periphery of the study area. Most stations show a coherent temporal pattern of dust frequency during the period 1973–1994, with the mid-1970s experiencing the most dust. Blowing dust generally was absent from all stations during 1979–1983, 1987–1989, and 1992–1994. The mid-1980s were moderately dusty and 1990–1991 saw a return to very dusty conditions, possibly resulting from below-normal precipitation and increased anthropogenic disturbances. Dust events in the Mojave Desert characteristically occur during the winter to spring months (February-May), associated with dry frontal activity, and are largely absent during the dry summer months. The Colorado Desert experiences a similar seasonal distribution of dust events, but has more summer events, usually associated with convective thunderstorms. Frequencies of blowing dust have weak, but statistically significant, correlations with mean annual and antecedent precipitation, suggesting that complex processes control dust emission. [Key words: blowing dust, dust storms, Mojave Desert, Colorado Desert, wind erosion.] 相似文献
19.
The regional characteristics of dust events in China has been mainly studied by using the data of dust storm, wind-blown sand and floating dust from 338 observation stations through China from 1954 to 2000. The results of this study are as follows: (1) In China, there are two high frequent areas of dust events, one is located in the area of Minfeng and Hotan in the South Xinjiang Basin, the other is situated in the area of Minqin and Jilantai in the Hexi Region. Furthermore, the spatial distributions of the various types of dust events are different. The dust storms mainly occur in the arid and semiarid areas covering the deserts and the areas undergoing desertification in northern China. Wind-blown sand and floating-dust not only occur in the areas where dust storms occur, but also extend to the neighboring areas. The range of wind-blown sand extends northeastward and southeastward, but floating-dust mainly extends southeastward to the low-latitude region such as the East China Plain and the area of the middle and lower reaches of the Yangtze River. Compared with wind-blown sand, the floating-dust seldom occurs in the high latitude areas such as North Xinjiang and Northeast China. (2) The affected areas of dust storms can be divided into seven sub-regions, that is, North Xinjiang Region, South Xinjiang Region, Hexi Region, Qaidam Basin Region, Hetao Region, Northeastern China Region and Qinghai-Xizang (Tibet) Region. The area of the most frequent occurrence of dust storms and floating-dust is in South Xinjiang Region, and of wind-blown sand in the Hexi Region. In general, the frequency of dust events in all the seven regions shows a decreasing tendency from 1954 to 2000, but there are certain differences between various dust events in different regions. The maximum interannual change and variance of dust events during this time happened in South Xinjiang Region and Hexi Region. The dust events generally occur most frequently in April in most parts of China. The spring occurred days of dust events occupied 60-70% of the whole year in Hetao Region and Northeastern China Region. However, in South Xinjiang Region and North Xinjiang Region, which was less affected by monsoon climate, dust events may occur at any time of the year, less than 50% of the events in this region occur during spring. In the remaining three regions 50-60% of the dust events occur in spring of a year. 相似文献