我国季平均气温和降水局地同时相关的时空特征   总被引：8，自引：0，他引：8       下载免费PDF全文

周晓霞  王盘兴  段明铿  林开平 《应用气象学报》2007,18(5):601-609

将1955—1998年我国160站冬、夏季平均气温和总降水量序列分解为年代际和年际变化两个部分，用方差分析、相关分析和奇异值分解方法，分析了两种要素序列的方差构成及要素间局地相关关系的性质、季节变化和地理分布。结果表明:我国冬夏季气温、降水异常序列中，总方差年际变化大于年代际变化，但按自由度均分的方差，年代际变化较年际变化大，尤以气温为甚；单站气温、降水同时相关图上，夏季表现为显著的负相关，显著区主要分布在35°N以南、105°E以东的地区；夏季局地温度、降水也呈显著负相关关系，进一步分析表明，干热、湿凉型异常夏季多发生在江淮和华南两区，但同一年中两区夏季异常型常相反，它由年代际和年际变化中的负相关共同构成。  相似文献   

华北地区云凝结核的观测研究   总被引：18，自引：1，他引：18       下载免费PDF全文

石立新  段英 《气象学报》2007,65(4):644-652

利用连续气流纵向热梯度云凝结核仪对中国华北地区空中和地面的云凝结核(CCN)进行了观测研究。2005年秋季和2006年春季的飞机观测结果表明,华北地区的CCN主要来源于地面,近地层CCN浓度较高,CCN浓度随高度增加而减少;CCN的分布与地面源地密切相关,污染地区乡村上空CCN浓度比无污染地区乡村高5倍以上,而污染城市上空的CCN浓度无显著差异;水平穿越淡积云云簇时云内CCN明显减少,表明云对CCN的消耗作用。2005年夏季石家庄地面CCN观测显示,同一过饱和度(S)下的CCN浓度差异很大,在S=0.1%、0.3%和0.5%下的最小值分别为584、808和2431个/cm3,最大值分别为9495、16332和21812个/cm3;CCN有明显的日变化,06时以后浓度开始上升,上午至中午前后达到极大值,下午浓度下降,原因可能是由于上午汽车排放以及光化学产物开始增加所致;降水对CCN具有冲刷作用。本文根据关系式N=CSk拟合得到的空中和地面的CCN活化谱参数C值明显较大(大于1000),k值较高(约0.7),表明华北地区CCN具有大陆性特征。  相似文献   

站址迁移对高要站气候资料序列的影响和分析   总被引：1，自引：0，他引：1  

李年  曹明会  彭端 《气象研究与应用》2007,28(3):80-82

对广东省高要市气象站迁站前20a和迁站后5a的气象资料统计分析,找出迁站前后观测资料序列差异较大的气象要素,分析其引起差异的原因。经对本站及邻站四会、德庆站同期相关资料序列进行了"t检验分析",高要站资料序列差异性显著,而四会、德庆站的资料序列的差异性不显著,说明高要站迁移前与迁移后的资料序列的差异并非由气候变化引起,而新旧站的地理环境差异才是造成资料序列差异的主要原因。  相似文献   

A simulation study on pre-landfall erratic track of typhoon Haitang (2005)     

H. Yu  W. Huang  Y. H. Duan  J. C. L. Chan  P. Y. Chen  R. L. Yu 《Meteorology and Atmospheric Physics》2007,97(1-4):189-206

Summary A new typhoon model named as GRAPES_TCM is applied to study the pre-landfall erratic track of Typhoon Haitang (2005), which hit China twice in mid-July by making landfall in Taiwan and Fujian provinces consecutively. The model is based on the Chinese Global/Regional Assimilation and PrEdiction System (GRAPES) and put into real-time operational test since 2004. It predicts almost correctly the pre-landfall loop and sharp turn of Haitang and its asymmetric rainfall distribution. Haitang’s erratic track is well explained by the potential vorticity (PV) theory on tropical cyclone motion, with the typhoon center moving toward the area of maximum wave-number 1 (WN1) PV tendency most of the time. Among the terms contributing to the WN1 PV tendency, the horizontal advection of PV is dominant with the diabatic heating and residual terms also being not negligible. A sensitivity experiment is carried out with removal of the Taiwan terrain to determine its importance in the erratic track of Haitang and it is found that the basic erratic feature of Haitang’s track remians unchanged although it tends to have a larger loop and a weaker northward turn, which suggests that Taiwan terrain may not be a key factor here. The sudden change of Haitang’s moving direction is always accompanied by a newly-generated or re-intensified WN1 PV center in the southern semicircle, which circles around the TC center cyclonically afterwards and weakens in the north or northwestern part. A phase-lock WN1 PV forcing related to diabatic heating is proposed to be the major contributor, the importance of which is magnified as it is in phase with the WN1 horizontal advection of PV. The intrusion of mid-level warm and dry air, as well as the existence of a low-level southwesterly jet, is considered to be the main reasons for such a phase-lock of the diabatic heating forcing on the PV tendency field that finally results in the erratic track of Haitang.  相似文献   

低纬高原地区MM5v3不同参数化方案降水模拟试验   总被引：1，自引：2，他引：1  

段旭  王曼  刘建宇  段玮 《气象》2006,32(4):16-23

为了进一步了解MM5模式在低纬高原降水预报性能，利用MM5模式中的3个物理过程组合了7个不同的参数化试验方案，对低纬高原地区2005年主汛期进行了降水数值试验。结果表明：第三重嵌套网格中的Grell积云参数化、Goddard显式水汽和Cloud（或RRTM）辐射过程组合的试验方案对降水预报效果较好，特别是对大雨和暴雨预报有明显的改善；在将试验结果插值到测站点时，不同扫描半径对插值结果有一定影响，相对而言，20～30km扫描半径插值结果较为理想。  相似文献   

全球大气位势高度场气候变率的球函数分析          下载免费PDF全文

闫巨盛王盘兴  段明铿李巧萍 叶玲萍 《应用气象学报》2006,17(2):145-151

为了研究全球大气位势高度场的气候变率, 利用NCEP/NCAR再分析资料, 按照距平高度场平均强度指数 (I_a) 分析发现, 半球距平高度场强度呈年单周振荡, 冬大夏小, 冬季随高度单调增大, 夏季有弱高、低值中心出现, 而北、南半球的差异明显表现在季节变化上; 进一步根据半球大气位势高度距平场球函数谱低维、低阶的基本特征, 将半球环流异常分为半球均匀异常 ( H ′₀₀)、纬向均匀异常 ( H ′₀)、超长波尺度异常 ( H ′_ul) 和长波尺度异常 ( H ′_l) 4种类型, 用波数域0≤m, k≤6上的球函数系数资料求得它们的方差贡献, 给出了4类异常的方差贡献随高度、季节变化的规律以及它们的半球际差异。由此得到异常环流球函数谱结构的总体特征为:对流、平流层之间存在明显变化。从对流层进入平流层, 一般由超长波异常为主转为纬向均匀异常为主 (冬半球) 或半球均匀为主 (夏半球); 半球均匀异常在对流层中不重要, 长波尺度异常在平流层中不重要, 它们拟合异常方差一般均小于10%; 北、南半球最大差异表现在冬季平流层R′₀₀和冬、夏季对流层R′₀南半球大于北半球, 冬、夏季对流层R′_l北半球大于南半球。  相似文献   

Effects of blue light on gametophyte development of Laminaria japonica (Laminariales, Phaeophyta)     

Shi Cuijuan  Kataoka Hironao  Duan Delin 《中国海洋湖沼学报》2005,23(3):323-329

Laminaria gametophyte was greatly influenced by light in its growth and development. Using light-emitting diodes (LED) as blue and red light sources, we analyzed the light effect on gametophytes development ofLaminaria japonica Aresch. The gametophytes were obtained from zoospores collected in April, May, July, 2003 and September, 2004. We found that the growth of gametophytes was stimulated by increasing intensity of blue light (BL) and red light (RL) illumination, of which BL was obviously stronger than that of RL. The fertilization of gametophytes depended largely on BL, and only sufficient BL illumination could take the reproductive effect. In addition, we noticed that there was a significant difference in light responses for gametophytes developed from zoospore collected in different times. For zoospores released in April, under BL₁ (73.90 μmol photons/m·s), the unicellular female gametophytes and multi-cellular male gametophytes produced eggs and sperms respectively, and further developed towards sporophytes. However, for gametophytes developed in May, July or September, they became multi-cellular and never formed oogonia or antheridia. It is believed that theLaminaria sporangium maturation stage could affect the gametophytes reaction to BL under laboratory culture conditions. Therefore, cryptochrome- or phototropin-like BL photoreceptors is probably involved in BL-induced development ofLaminaria gametophytes. This research was supported by the NSFC (No.40376049) and Japan Society for the Promotion of Science (The Invitation Fellowship for Research in Japan 2002).  相似文献   

Observation of female gamete (Carpogonia) germination of Porphyra yezoensis and P. oligospermatangia     

Mei Junxue  Eei Xiuigeng  Duan Delin 《中国海洋湖沼学报》2005,23(4):414-417

Several papers have reported that part or whole leafy thallus seemingly consisting of zygotospores can give rise to both blades and conchocelis in the same culture ofPorphyra. Study on samples of wild and cultivatedPorphyra yezoensis andP. oligospermatangia were conducted to clarify the origination of the young blades in the culture. It is confirmed that single cells on the blade of both species, which normally intermixed with zygotospores, germinated into young blades. TEM and SEM observation has shown that the single cells ofPorphyra yezoensis had typical features of female gamete (carpogonia) but archeospore. Therefore, the female gametes are responsible in developing leafy thalli. This project was sponsored by the NSFC (No. C-0205-05-39770593)  相似文献   

对东亚夏季风与西北太平洋热带气旋频数关系的初步分析   总被引：27，自引：1，他引：27       下载免费PDF全文

孙秀荣  端义宏 《大气科学》2003,27(1):67-74

利用海陆热力差指数(ILSTD)、500 hPa位势高度场、向外长波辐射(OLR)资料及NCEP/NCAR月平均再分析数据集,分析东亚夏季风与西北太平洋地区(包括中国南海)热带气旋频数的关系,结果表明,在强夏季风年西北太平洋地区热带气旋频数偏多,而弱夏季风年同期热带气旋频数异常偏少而后期趋于正常,正常夏季风年热带气旋频数基本正常.并结合热带气旋形成的大尺度环流条件,对其动力机制作了初步探讨.  相似文献   

云南降水正态分布特征的初探   总被引：7，自引：0，他引：7       下载免费PDF全文

陶云  段旭 《气象科学》2003,23(2):161-167

利用适合性检验方法，对云南省125个测站1961年一2000年40a逐月降水资料是否符合正态分布进行了检验，并对云南降水正态分布做了区划。研究结果表明，云南在雨季(5—10月)通过显著性检验的测站数明显少于干季(11一次年4月)通过显著性检验的测站数，其中8月份仅4站次通过显著性检验，而12月份高达97站次，占全省总站次的77．6％；即云南雨季降水多符合正态分布，而在于季多符合非正态分布，8月份几乎全省符合正态分布，而12月份大部份测站都不符合正态分布。云南降水量的正态统计分布一方面具有一定的区域性特征，另一方面又具有较强的局地性，不同的月份同一测站降水量的正态性不同。因此，在做有关降水量的分析预报时，很有必要考虑其正态性的统计分布特征。  相似文献