NUMERICAL SIMULATIONS ON INFLUENCES OF VARIATION OF SEA ICE THICKNESS AND EXTENT ON ATMOSPHERIC CIRCULATION

By using a 2-layer AGCM designed by Institute of Atmospheric Physics,Chinese Academy ofSciences.this paper investigates influences of thickness and extent variations in Arctic sea ice onthe atmosphere circulation,particularly on climate variations in East Asia.The simulation resuhshave indicated that sea ice thickness variation in the Arctic exhibits significant influences onsimulation results,particularly on East Asian monsoon.A nearly reasonable distribution of sea icethickness in the model leads directly to stronger winter and summer monsoon over East Asia.andimproves the model's simulation results for Siberia high and Icelandic low in winter.On the otherhand,sea ice thickness variation can excite a teleconnection wave train across Asian Continent,andin low latitudes,the wave propagates from the western Pacific across the equator to the easternPacific.In addition,the variation of sea ice thickness also influences summer convective activitiesover the low latitudes including South China Sea and around the Philippines.Effects of winter sea ice extents in the Barents Sea on atmospheric circulation in the followingspring and summer are also significant.The simulation result shows that when winter sea iceextent in the target region is larger (smaller) than normal.(1)in the following spring (averagedfrom April to June).positive (negative) SLP anomalies occupy the northern central Pacific.whichleads directly to weakened (deepened)Aleutian low.and further favors the light (heavy) sea icecondition in the Bering Sea:(2)in the following summer,thermal depression in Asian Continent isdeepened (weakened).and the subtropical high in the northwestern Pacific shifts northward(southward) from its normal position and to be strengthened (weakened).     

大气科学研究的一个前沿领域───气候系统动力学与气候预测

从气候环境的变化及其对工农业和人类生活的影响论述了气候系统动力学和气候预测研究在地球科学中的地位和作用，指出气候系统动力学与气候变化预测是当今大气科学的一个重要前沿研究领域；并从气候系统及其各子系统的相互作用论述了气候系统动力学与气候预测的研究对象和主要研究内容；此外，还从当今气候和环境科学发展的趋势和特点指出气候动力学研究应采取的研究路径与方法。     

辐散风和瞬变的涡度通量的异常对定常波年际异常的强迫作用

研究了１９８２／１９８３年１２—２月对流层上层由辐散风和瞬变的涡度通量所产生的涡度源异常对定常波异常的强迫作用。结果表明，瞬变的涡度通量辐合的异常有抵消或耗散辐散风产生的涡度源异常的趋势；定常波的异常是在这两种强迫力的共同作用下维持的。同时还表明，对１９８２／１９８３年的情况，热带和赤道中东太平洋上的涡度源异常以及中纬度北太平洋上的涡度源异常都对太平洋／北美地区的大气环流异常起了重要的作用。     

冬季热带西太平洋对流活动异常的年际变化及其对北太平洋风暴轴的影响

通过诊断分析指出，80年代菲律宾周围的对流活动2～4年周期振荡比较明显；北太平洋风暴轴中心有线性增强、偏北、偏东的趋势，2～4年周期振荡也比较明显；在2～4年时间尺度上，菲律宾周围对流活动的变化与北太平洋风暴轴的变化有密切联系:当菲律宾周围对流活动强（弱）时，北太平洋风暴轴中心偏强（弱）、偏东（西）、偏北（南）。诊断分析和数值模拟表明，产生这种联系的物理机制是，当菲律宾周围对流活动强（弱）时，在东亚-北太平洋-北美地区产生一个距平波列（ANA），位于美国西海岸的正（负）距平及其北侧的负（正）距平，使气压梯度增大（减小），北太平洋急流和风暴轴中心强度增强（减弱）、北抬（南退）、东伸（西退）。     

Numerical Simulation of the Relationship between the Anomaly of Subtropical High over East Asia and the Convective Activities in the Western Tropical Pacific

In this paper, a close relationship between the intraseasonal variation of subtropical high over East Asia and the convective activities around the South China Sea and the Philippines is analysed from OLR data.This relationship is studied by using the theory of wave propagating in a slowly varying medium and by using a quasi-geoslrophic, linear, spherical model and the IAP-GCM, respectively. The results show that when the SST is warming around the western tropical Pacific or the Philippines, the convective activities are intensified around the Philippines. As a consequence, the subtropical high will be intensified over East Asia. The computed results also show that when the anomaly of convective activities are caused around the Philippines, a teleconnection pattern of circulation anomalies will be caused over South Asia, East Asia and North America.     

一个描述河陆风变化的数值模式及其数值实验

本文设计了一个包括水平及垂直扩散、牛顿冷却的二维46层非弹性运动方程模式来模拟及研究河陆风的变化。在模式中包括了太阳辐射;地-气系统的长波辐射;地表面、河表面向大气的感热与潜热输送以及地表面向土壤层的热传导等物理过程。 本模式采用分解算法及隐式时间差分方案,计算结果表明,这个模式无论对稳定层结或不稳定层结其计算都是稳定的,且所需计算时间也是很节省的,其计算结果是符合实际的。     

夏季西藏高原与落基山脉对北半球定常行星波形成的动力作用

本文应用一个包括Rayleigh摩擦、Newton冷却与水平涡旋热力扩散准地转34层球坐标模式来研究夏季西藏高原与落基山脉地形强迫对于夏季北半球定常行星波形成的作用. 计算结果表明:夏季北半球地形强迫所产生的定常行星波的振幅与位相分布与冬季的分布是很不一样的,夏季地形强迫所产生的定常行星波主要集中在亚热带的对流层,并且可以发现纬向波数k=1与k=2的振幅在高纬度存在着第二峰值.计算结果还表明了夏季西藏高原与落基山对于夏季定常行星波的形成起了重要作用.     

THE CHARACTERISTICS OF THE FORCED STATIONARY PLANETARY WAVE PROPAGATIONS IN SUMMER NORTHERN HEMISPHERE

The three-dimensional propagations of the forced stationary planetary waves in a realistic summer current, in which the vertical and horizontal wind shears are included, are discussed by using the refractive index squared of waves in a spherical coordinate system.The results show that there is no polar wave guide in stationary planetary wave propagations in summer. Thus, stationary planetary waves cannot propagate into the stratosphere. However, there are a wave guide pointing from the subtropics toward middle and high latitudes in the troposphere and another wave guide pointing from the lower troposphere at middle latitudes toward the upper troposphere near 30°oN in the forced stationary planetary wave propagations.A linearized, steady-state, quasi-geostrophic 34-level spherical coordinate model with Rayleigh friction and Newtonian cooling, horizontal kinematic thermal diffusivity is used to simulate the wave guides of three-dimensional propagations of stationary planetary waves in summer.     

冬季热源位置与热源的南北宽度对定常行星波的影响

本文应用一个定常、准地转34层球坐标模式来讨论冬季北半球多层模式大气对定常热源强迫的响应. 计算结果表明:在冬季位于高纬度的定常热源强迫所产生的定常行星波的振幅要比位于中纬度的定常热源强迫所产生的定常行星波的振幅要大.计算结果也表明了热源的南北宽度愈宽,其强迫所产生的定常行星波的振幅愈大.     

几十年来大气环流与大尺度动力学的研究进展及2000年研究展望

一、大气环流与大尺度动力学的研究进展近几十年来,国际上关于大气环流与大尺度动力学的研究取得很大进展。一方面由于观测技术的提高使得全球大气环流的观测资料不断增多,不断揭示出许多大气环流规律;另一方面由于数学、物理学,特别是计算机与计算数学的蓬勃发展,使得大气环流与大尺度动力学从一种简单、定性论述的学科变成一种比较严格的数理学科。大气环流与大尺度动力学是气象学上一对孪生兄弟,大气环流的发展不断提出动力学问题,而动力学的重大突破加深了人们对大气环流的认识。大气环流应包括两个部分:一是从整体来看全球大气的运动形态、运动特征及其物理机制;二是它的各个组