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   

关于非纬向基流的特性及其扰动的传播     

高绍凤 《热带气象学报》1986,(1):17-22

本文在正压无辐散的条件下,讨论了非纬向基流的特性及其约束条件,指出低纬大气一些周期振荡是非纬向基流在β效应作用下的固有振荡。其次,从β平面上的正压涡度方程出发,在一定条件下导出了非纬向流扰动波速表达式。最后用实例加以验证。   相似文献   

500 hPa场的纬向平均地转风的经向廓线分布与稳定波型的联系     

方之芳 《大气科学进展》2001,18(5)

应用蒙特卡罗方法、奇异值分解（SVD）、自然正交分解（EOF）和回归分析等统计方法，探讨冬季北半球海平面气压场与 500 hPa高度场、500 hPa纬向平均场和纬偏场（Z5ua）中稳定波的联系。依据正交分解分析，海平面气压场的第一与第二特征向量权重之比远大于 500 hPa，其比值达2倍，而且它的第一特征场更具有纬向对称性。在应用蒙特卡罗方法讨论上述两场的第一与第二特征向量时间序列的差异时，海平面气压场第一特征向量是十分稳定的，不因随机抽样而改变，一再重复出现；因此认为海平面气压场的第一特征向量场比 500 hPa高度场具有更好的重复性和代表性。在比较海平面气压场第一特征向量时间序列（即北冰洋涛动指数）与 500 hPa场上 35°N－55°N纬向风差值（即 Ut指数）时，两者的相关达 0．85；在它们与 500hPa纬向平均风场的回归廓线图中。无论在振幅和极大极小值的位置上，都十分相似。在比较上述两指数与纬偏场（Z500）的回归场时，所有的正负大值中心，位置全部一一对应，中心值也相近，尤其在北大西洋和欧亚大陆。在 500 hPa纬向平均风场和纬偏场（Z500）的奇异值分解分析中，其结果正与上述两回归场相仿；应用正交分解分析Z500场，其第二特征向量场与上述的回归场也完全一致。因此认为这种覆盖整  相似文献   

ENSO事件对中高纬大气低频振荡的调频作用   总被引：7，自引：2，他引：5  

邱明宇  陆维松  陶丽 《南京气象学院学报》2004,27(3):365-373

采用诊断方法研究了El Nino和La Nina事件对中高纬大气低频振荡的调频作用。应用1950—1996年北半球中高纬逐日500 hPa高度场资料进行功率谱分析得出：夏季低频振荡较弱,冬季低频振荡较强;El Nino事件有使低频振荡周期缩短的趋势,La Nina事件有使低频振荡周期延长的趋势。  相似文献   

低纬度涛动——全球热带的甚低频振荡现象     

符淙斌  叶笃正 《大气科学》1989,13(3):255-264

本文在论证所谓“北方涛动”存在性的基础上,分析了这一现象与经典的“南方涛动”的关系和它们的性质,提出了”低纬度涛动”的概念。 研究发现,这两类振荡在低频域内具有相同的振荡频率,处于同一振荡系统内。实质上反映了印度洋和太平洋低纬地区三个主要活动中心——赤道低压和南、北太平洋副热带高压的年际变化之间的联系。 这个振荡系统,在气压场上表现为,横跨赤道南北各约30个纬距的东西向的“跷跷板”(seesaw)现象,且有以赤道为界的两个分量,即南方涛动和北方涛动。在温度、湿度场和低层大气稳定度场上,主要表现为热带太平洋上高温、高湿和强不稳定与低温,低湿和弱不稳定的交替出现;在云量场上表现为主要对流区的东西向位移;在海面温度场上为赤道太平洋增暖和降温的交替出现。它们之间通过热力和动力过程耦合起来,组成了全球热带海洋大气系统的振荡,这是低纬度大气环流年际变化的一个基本特征,我们称它为“低纬度涛动”。 分析表明,它的振荡周期平均约为40个月。为区别于40—60天的热带低频振荡,这一年际尺度的振荡可称为“甚低频振荡”。 作者用全球热带海平面气压第一特征向量的时间系数定义“低纬度涛动指数”,它能客观地同时描写气压场上振荡的两个分量,以及温度、湿度、云量和低层大气稳定度等的甚低频振荡特征。  相似文献   

沈阳两次降水过程中能见度的变化特征   总被引：1，自引：0，他引：1  

赵胡笳  马雁军  赵明  朱轶明  李潇潇 《气象与环境学报》2014,30(2):60-66

利用2011年7月29-31日,8月27-29日沈阳大气成分观测站的能见度资料,统计分析了能见度与降水强度、PM₁₀、PM _2.5、PM _1.0质量浓度、风速、相对湿度等气象要素的相关性。结果表明: 7月29-31日降水过程特点为个别时间内降水量较大,8月27-29日降水过程特点为持续几个小时都有较大降水量;7月29-31日和8月27-29日降水过程中,初期降水对PM的湿清除效果较好,后期随着降水强度的增加,能见度有所降低;7月29日0时-31日23时期间内,PM质量浓度在降水过程中出现5 μg•m^-3左右的低值是因为降水和较大风速的双重作用,而8月27日0时-29日23时期间内的降水过程中,风速较稳定,PM质量浓度的改变量相对较小;7月29日-31日和8月27日-29日降水过程中,平均风速与PM₁₀、PM _2.5、PM _1.0的变化趋势均呈反相关,较高的相对湿度有利于PM质量浓度的上升;7月29-31日和8月27-29日降水过程中,能见度与PM _2.5/PM₁₀、PM _1.0/PM₁₀的比值变化趋势均呈明显的反相关。随着颗粒物粒径的减小,其与能见度的相关性逐渐增加。  相似文献   

中高纬大气季节内振荡特征的诊断研究     

王召民  倪允琪  张勤 《气象科学》1992,(3)

本文采用ECMRWF1980—1988年u,v,z格点资料,进行Munakami带通滤波,分析中高纬大气季节内振荡的动力学特征及传播特征,以及与热带地区季节内振荡的差异。 在全球高度场单点相关图上,南北半球都有类似于波列的分布结构,它们有相同的视源区与视汇区,季节内振荡具有全球尺度特征。超前或滞后相关图上,可以发现季节内振荡具有40—50天振荡周期。 在高度场四个位相合成图上,我们发现中高纬高度场上反映的季节内振荡为定常波的振荡,即波列位相与振幅的振荡。 低纬地区速度势函数冬季为纬向一波结构,夏季为二波结构。合成的赤道区域时剖图上,冬季X场东传明显,夏季则仅东半球有东传现象。OLR场冬季主要为150E为节点的东西向偶极形式的振荡以及60W—O范围的局地振荡。 热带区域季节内振荡主要表现为行星波的传播,而中高纬大气的季节内振荡表现为定常波的振荡。  相似文献   

1979年夏季40—50天周期振荡的空间结构及其位相传播   总被引：2，自引：0，他引：2  

何金海  Murakami  T.  Nakazawa  T. 《南京气象学院学报》1985,(1)

本文根据FGGE Level Ⅲb资料详细分析了1979年夏季大范围内(30°S—30°N,30°E—150°W)40—50天周期振荡的空间分布及其传播特点。结果证实了早先关于“这些低频振荡主要表现为纬向风振荡”的究研结果,且它们向东向北传播。而季风区域850毫巴经向风的振荡周期却小于10天,这或许反映了这一地区季风扰动的活跃。在赤道,40—50天周期的纬向风的扰动系统地向东(600公里/天)和向上(0.7公里/天)传播。纬向风、位势高度和大尺度的“视热源”场之间的位相关系表明这些扰动确实不象大气中的开尔文波。与赤道地区不同,沿着15°N的纬向风的位相虽然也向东传播但不很系统。在这一纬度,纬向风的振荡在季风地区是低层显著,而西太平洋地区是在高层显著。这两个系统的相互作用导致西风或东风在阿拉伯海地区向下传播。西风(东凤)向下的位相对应着南亚和东南亚地区季风活跃(中断)的开始。  相似文献   

全球大气季节内振荡的机制研究     

王召民  张勤 《气象科学》1993,13(3):281-288

本文利用经过滤波的1980—1988年欧洲中心资料及1980—1983年OLR滤波资料,初步分析了全球大气季节内振荡的机制,得到如下结果:全球大气的季节内振荡有内在联系。赤道区域势函数场的季节内振荡表现为行星波的东传。OLR场在60E—150W范围有东传,60W—0有明显的40—50天振荡。散度场则表现为散度中心的孤立局地振荡。在季节内时间尺度上,暖水域上OLR振荡中心与散度振荡中心相对应;冷水域上散度振荡中心则没有OLR振荡中心对应。低纬散度场的40—50天振荡与中高纬季节内振荡有很好的相关。低纬区域60E—150W与60W—0范围的OLR季节内振荡可能是南北半球中高纬大气季节内振荡的源。  相似文献   

夏季低纬地区散度风分量准40天振荡的观测研究     

章基嘉  吴洪宝 《气象科学》1991,11(1):1-10

本文用ECMWF逐日资料分析了1982年夏季30°S—30°N纬带散度风分量Vx准40天振荡的空间分布和传播特点。结果表明:整个纬带振荡周期长度比较一致;高低层间反位相,辐散与辐合相反配置;强度分布有明显地域性,季风区最强,850和200hPa上振幅分别是1和2m/s左右,亦道附近110°W两侧(?)x有分别向东西两个方向传播的现象。  相似文献   

一维气候时间序列的李亚普诺夫指数所显示的动态系统的演化特征   总被引：2，自引：0，他引：2  

严绍瑾  彭永清  王建中 《热带气象学报》1990,(3):210-217

本文利用广州1873—1980年共108年的月平均气温时间序列资料,在拓展了的三维相空间中,用Wolf的方法,求出了在不同参数条件下的李亚普诺夫指数λ₁。从中发现,对每一组参数,均得到λ_1,2>0（其中λ₁>λ₂）,λ₃<0。这说明我国季风区短期气候演化存在着浑沌吸引子,因而气候应该分享经历着浑沌力学行为的体系所具有的那种本征的演化特征。   相似文献   

Broadband extinction method to determine atmospheric aerosol optical properties   总被引：7，自引：0，他引：7  

JINHUAN QIU 《Tellus. Series B, Chemical and physical meteorology》2001,53(1):72-82

The equivalent wavelength ( λ _E), at which the aerosol optical depth (AOD) is equal to broadband AOD (BAOD), can change in a wide range from 0.619 μm to 1.575 μm in the usual aerosol conditions. By using the least squares technique and some empirical corrections, a parameterized relationship of λ _E with BAOD, Ångström wavelength exponent ( α ), solar zenith angle ( θ ₀) and H₂O amount is developed. Using this relationship, and based on the strong sensitivity of BAOD on θ ₀ when θ ₀>70°, the broadband extinction method to derive the spectral AOD and α is further proposed. As shown in comparative simulations to retrieve AOD by the present, Molineaux et al. and Gueymard methods, the present method has the best accuracy in most simulations using Junge, MODTRAN, log‐normal and Deirmendjian aerosol models. A key question of the pyrheliometer method to determine wavelength-dependent AODs is the effect of uncertainty in the aerosol size istribution. It is found that the AOD solution around λ _E is less sensitive to the uncertainty. The wavelength exponent α is derived using an assumption of the stable atmospheric turbidity. If the pyrheliometer data from θ ₀=85° to 70° are used and the change of the turbidity is ±10%, the error of solution α is usually within ±0.32. If the variation of the turbidity is random, the mean value of a lot of the measurements of α would be very reasonable.  相似文献   

Vertical profiles and storage fluxes of CO₂, heat and water in a tropical rainforest at Pasoh, Peninsular Malaysia     

SHINJIRO OHKUBO  YOSHIKO KOSUGI  SATORU TAKANASHI  NAOKO MATSUO  MAKOTO TANI  ABDUL RAHIM NIK 《Tellus. Series B, Chemical and physical meteorology》2008,60(4):569-582

Ambient CO₂ concentration, air temperature and relative humidity were measured intermittently for a 3-year period from the floor to the canopy top of a tropical rainforest in Pasoh, Peninsular Malaysia. Mean diurnal CO₂ storage flux ( S _c; μmol m⁻² s⁻¹) and sensible and latent heat storage fluxes ( Q _a and Q _w; W m⁻²) ranged from −12.7 to 3.2 μmol m⁻² s⁻¹, −15 to 27 W m⁻² and −10 to 20 W m⁻², respectively. Small differences in diurnal changes were observed in S _c and Q _a between the driest and wettest periods. Compared with the ranges of mean diurnal CO₂ eddy flux (−14.7 to 4.9 μmol m⁻² s⁻¹), sensible eddy flux (−12 to 169 W m⁻²) and latent eddy flux (0 to 250 W m⁻²), the contribution of CO₂ storage flux was especially large. Comparison with summertime data from a temperate Japanese cypress forest suggested a higher contribution of S _c in the tropical rainforest, probably mainly due to the difference in nighttime friction velocity at the sites. On the other hand, differences in Q _a and Q _w were smaller than the difference in S _c, probably because of the smaller nighttime sinks/sources of heat and water vapour.  相似文献   

Measurements of aerosol optical depth above 3570 m asl in the North Atlantic free troposphere: results from ACE‐2     

Paola Formenti  Meinrat O. Andreae  Jos Lelieveld 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):678-693

As part of the 2nd A erosol C haracterisation E xperiment (ACE‐2), conducted during summer 1997 in the North Atlantic region between the Canary Islands and Portugal, we measured aerosol optical depths (AOD) at a mid‐tropospheric site, near the top of the volcanic mountain "El Teide"(28°16'N, 16°36' W, 3570 m asl). Our instrument was located at the highest altitude in a network of sunphotometers that extended down to sea level. Clear conditions dominated the ACE‐2 period, and, although suggested by back‐trajectories at 300 hPa, no evidence of anthropogenic pollution was found in our data. Three distinct dust episodes were observed. Vertical soundings and back trajectories suggested mineral dust from the Sahel region as a source. During these episodes, AOD increased an order of magnitude with respect to background conditions (from 0.017 up to 0.19 at λ=500 nm). A shift towards neutrality of the extinction spectral dependence (Ångstrom exponent α down to 0.13), indicated that the coarse mode (particle diameter >2 μm) dominated the aerosol size distribution. For 6 days during the episodes of mineral dust, a monomodal size distribution between 2 and 20 μm diameter was obtained from Mie based size distribution calculations. Estimates, at 500 nm, of the single scattering albedo ω₀(0.87–0.96), and the aerosol asymmetry parameter g (0.72–0.73) suggest that the dust layer causes a net cooling forcing at the top of the atmosphere.  相似文献   

Aircraft study of aerosol vertical distributions over Beijing and their optical properties   总被引：3，自引：0，他引：3  

By PENGFEI LIU  CHUNSHENG ZHAO  QIANG ZHANG  ZHAOZE DENG  MENGYU HUANG  XINCHENG MA  XUEXI TIE 《Tellus. Series B, Chemical and physical meteorology》2009,61(5):756-767

A set of 152 vertical profiles of aerosol number concentration and size distribution with diameter ranging from 0.12 to 3.0 μm observed by the airborne optical spectrometer probe in Beijing, China, between February 2005 and September 2006 is analysed and discussed. The statistic of aerosol number concentration ( N _a) reveals a high aerosol number density in this region with average surface level number concentration ( N ₀) of about 6600 cm⁻³ (0.12–3.0 μm). The average vertical profile of N _a approximately satisfies an exponential decline function with a scale height of 1419 m. The N _a profiles are influenced by the structures of planetary boundary layer (PBL) significantly and two typical types of N _a profile under different conditions of PBL are presented and parametrized in this study. The observations of aerosol size distribution show that, in most cases the aerosol size distributions are not very sensitive to altitude, with effective radii ranging from 0.16 to 0.28 μm. Comparison between aircraft-derived aerosol optical depth (AOD) and Moderate Resolution Imaging Spectroradiometer-derived AOD shows good agreement. The Mie model calculations suggest that the surface level number concentration, the PBL height and the structure of PBL can influence the AOD significantly.  相似文献   

北京等7个气象台站太阳总辐射观测资料的准确度评估          下载免费PDF全文

邱金桓  许潇锋  杨景梅 《应用气象学报》2008,19(3):287-296

基于地面太阳短波总辐射对气溶胶光学特性和地表反照率的敏感性, 该文提出了一个评估我国气象台站总辐射资料准确度的方法。该方法选用气溶胶光学厚度和太阳天顶角较小情形下的晴天辐射资料, 从太阳直射辐射反演气溶胶光学厚度, 用于计算宽带透过率, 再从该透过率和总辐射资料反演太阳常数E_{0, P}, 并采用E_{0, P}对世界辐射基准 (WRR) 的偏差表示总辐射资料的不确定性。模拟结果表明:气溶胶折射率虚部和大气柱水汽含量的输入误差是两个主要的评估不确定因子。用于准确度评估的资料越多, 越有利于平滑气溶胶、水汽含量等输入参数随机误差的效应, 评估结果越合理。应用这一方法, 该文评估了2000— 2004年我国沈阳、额济纳旗、北京、乌鲁木齐、格尔木、上海和广州7个气象台站总辐射资料的准确度。7个站共有1161个太阳常数反演值, 都满足太阳天顶角余弦 (μ₀) 大于0.7的条件。这些E_{0, P}值对WRR的最大偏差为7.33%, 97.78%的E_{0, P}值对WRR的偏差小于5%, 总平均E_{0, P}值对WRR偏差只有-1.15 %。依据这些结果, 当μ₀≥0.7时, 这些台站的晴天总辐射资料的不确定度估计为5%。  相似文献   

西北太平洋历史台风风场重建模型参数试验          下载免费PDF全文

孔莉莎  张秀芝 《应用气象学报》2022,33(1):56-68

基于Yan Meng风场模型,使用中国近海浮标观测资料,对影响风场模拟的台风最大风速半径Rmax、压力分布常数B、粗糙度z03个参数进行估算试验,结果表明:台风中心最大风速Vmax和台风所处纬度的组合方案对估算Rmax更合理;海面(浮标站)在z0=0.005 m,B=1.0时风速模拟效果较好.选取登陆闽北浙江、北上东海...  相似文献   

Evolution of boundary‐layer aerosol particles due to in‐cloud chemical reactions during the 2nd Lagrangian experiment of ACE‐2     

Anthony J. Dore  Douglas W. Johnson  Simon R. Osborne  Thomas W. Choularton  Keith N. Bower  Meinrat O. Andreae  Brian J. Bandy 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):452-462

The second Aerosol Characterisation Experiment (ACE‐2) was aimed at investigating the physical, chemical and radiative properties of aerosol and their evolution in the North Atlantic region. In the 2nd "Lagrangian" experiment, an air mass was tracked over a 30‐h period during conditions of extensive stratocumulus cover. Boundary‐layer measurements of the aerosol size distribution obtained with a passive cavity aerosol spectrometer probe (PCASP) during the experiment show a gradual growth in size of particles in the 0.1–0.2 μm diameter mode. Simultaneously, SO₂ concentrations were found to decrease sharply from 800 to 20 ppt. The fraction of sulphate in aerosol ionic mass increased from 0.68±0.07 to 0.82±0.09 for small particles (diameter below 1.7 μm) and from 0.21±0.04 to 0.34±0.03 for large particles (diameter above 1.7 μm). The measurements were compared with a multicyclic parcel model of gas phase diffusion into cloud droplets and aqueous phase chemical reactions. The model was able to broadly reproduce the observed transformation in the aerosol spectra and the timescale for the transformation of SO₂ to sulphate aerosol. The modelled SO₂ concentration in the boundary layer fell to below half its initial value over a 6.5‐h time period due to a combination of the entrainment of cleaner tropospheric air and cloud chemical reactions. NH₃ and HCl gas were also found to play an important rôle in cloud processing in the model.  相似文献   

Chemical composition of the background aerosol at two sites in southwestern and northwestern China: potential influences of regional transport   总被引：1，自引：0，他引：1  

WEN J. QU  XIAO Y. ZHANG  RICHARD ARIMOTO  DAN WANG  YA Q. WANG  LI W. YAN  YANG LI 《Tellus. Series B, Chemical and physical meteorology》2008,60(4):657-673

Concentrations of organic carbon (OC), elemental carbon (EC), selected trace elements and water-soluble (WS) ions were determined for samples collected from August 2004 to February 2005 to assess the aerosol background at two remote sites in China. The OC and EC concentrations in PM₁₀ from near the Tibetan Plateau at Zhuzhang (ZUZ) were comparable with other background sites, averaging 3.1 and 0.34 μg m⁻³, respectively, with no pronounced seasonality. At Akdala (AKD) on northern margin of the Zhungaer Basin, the average concentrations were similar (mean OC = 2.9 μg m⁻³ and EC = 0.35 μg m⁻³), but the concentrations were higher in winter. The aerosol mass at both sites was dominated by OC and SO₄²⁻, but a stronger contribution from soil dust was observed at AKD. At ZUZ, NO₃⁻ showed a unique weather-related fluctuation in PM₁₀ with a periodicity of ∼1 week. Anthropogenic sources in the Sichuan Basin and southeastern Yunnan Province evidently influence ZUZ in summer and autumn while pollutants from Russia and the China–Mongolia border affect AKD nearly all year. The identification of these upwind sources demonstrates that transboundary transport needs to be taken into account when assessing air quality in remote parts of China.  相似文献