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1.
The effect of snow on Antarctic sea ice simulations in a coupled atmosphere-sea ice model 总被引：1，自引：0，他引：1
The effect of a snow cover on sea ice accretion and ablation is estimated based on the ‘zero-layer’ version sea ice model
of Semtner, and is examined using a coupled atmosphere-sea ice model including feedbacks and ice dynamics effects. When snow
is disregarded in the coupled model the averaged Antarctic sea ice becomes thicker. When only half of the snowfall predicted
by the atmospheric model is allowed to land on the ice surface sea ice gets thicker in most of the Weddell and Ross Seas but
thinner in East Antarctic in winter, with the average slightly thicker. When twice as much snowfall as predicted by the atmospheric
model is assumed to land on the ice surface sea ice also gets much thicker due to the large increase of snow-ice formation.
These results indicate the importance of the correct simulation of the snow cover over sea ice and snow-ice formation in the
Antarctic. Our results also illustrate the complex feedback effects of the snow cover in global climate models. In this study
we have also tested the use of a mean value of 0.16 Wm-1 K-1 instead of 0.31 for the thermal conductivity of snow in the coupled model, based on the most recent observations in the eastern
Antarctic and Bellingshausen and Amundsen Seas, and have found that the sea ice distribution changes greatly, with the ice
becoming much thinner by about 0.2 m in the Antarctic and about 0.4 m in the Arctic on average. This implies that the magnitude
of the thermal conductivity of snow is of considerable importance for the simulation of the sea ice distribution. An appropriate
value of the thermal conductivity of snow is as crucial as the depth of the snow layer and the snowfall rate in a sea ice
model. The coupled climate models require accurate values of the effective thermal conductivity of snow from observations
for validating the simulated sea ice distribution under the present climate conditions.
Received: 20 November 1997/Accepted: 27 July 1998 相似文献
2.
3.
Modelling the influence of snow accumulation and snow-ice formation on the seasonal cycle of the Antarctic sea-ice cover 总被引：5，自引：5，他引：0
Recent observational and numerical studies of the maritime snow cover in the Antarctic suggest that snow on top of sea ice
plays a major role in shaping the seasonal growth and decay of the ice pack in the Southern Ocean. Here, we make a quantitative
assessment of the importance of snow accumulation in controlling the seasonal cycle of the ice cover with a coupled snow–sea-ice–upper-ocean
model. The model takes into account snow and ice sublimation and snow deposition by condensation. A parametrisation of the
formation of snow ice (ice resulting from the freezing of a mixture of snow and seawater produced by flooding of the ice floes)
is also included. Experiments on the sensitivity of the snow–sea-ice system to variations in the sublimation/condensation
rate, the precipitation rate, and the amount of snowfall transported by the wind into leads are discussed. Although we focus
on the model response in the Southern Hemisphere, results for the Arctic are also discussed in some cases to highlight the
relative importance of the processes under study in both hemispheres. It is found that the snow loss by sublimation can account
for the removal of 0.45 m of snow per year in the Antarctic and that this loss significantly affects the total volume of snow
ice. A precipitation decrease of 50% is conducive to large reductions in the Antarctic snow and snow-ice volumes, but it leads
only to an 8% decrease in the annual mean ice volume. The Southern Ocean ice pack is more sensitive to increases in precipitation.
For precipitation rates 1.5 times larger than the control ones, the annual mean snow, ice, and snow-ice volumes augment by
30, 20, and 180%, respectively. It is also found that the transfer to the ocean of as much as 50% of the precipitating snow
as a result of wind transport has almost negligible effects on the total ice volume. All the experiments exhibit a marked
geographical contrast in the ice-cover response, with a much larger sensitivity in the western sector of the Southern Ocean
than in the eastern sector. Our results suggest that snow-related processes are of secondary importance for determining the
sensitivity of the Arctic sea ice to environmental changes but that these processes could have an important part to play in
the response of the Antarctic sea-ice cover to future, or current, climatic changes.
Received: 30 June 1997/Accepted: 2 October 1998 相似文献
4.
F. J. Saucier S. Senneville S. Prinsenberg F. Roy G. Smith P. Gachon D. Caya R. Laprise 《Climate Dynamics》2004,23(3-4):303-326
The seasonal cycle of water masses and sea ice in the Hudson Bay marine system is examined using a three-dimensional coastal ice-ocean model, with 10 km horizontal resolution and realistic tidal, atmospheric, hydrologic and oceanic forcing. The model includes a level 2.5 turbulent kinetic energy equation, multi-category elastic-viscous-plastic sea-ice rheology, and two layer sea ice with a single snow layer. Results from a two-year long model simulation between August 1996 and July 1998 are analyzed and compared with various observations. The results demonstrate a consistent seasonal cycle in atmosphere-ocean exchanges and the formation and circulation of water masses and sea ice. The model reproduces the summer and winter surface mixed layers, the general cyclonic circulation including the strong coastal current in eastern Hudson Bay, and the inflow of oceanic waters into Hudson Bay. The maximum sea-ice growth rates are found in western Foxe Basin, and in a relatively large and persistent polynya in northwestern Hudson Bay. Sea-ice advection and ridging are more important than local thermodynamic growth in the regions of maximum sea-ice cover concentration and thickness that are found in eastern Foxe Basin and southern Hudson Bay. The estimate of freshwater transport to the Labrador Sea confirms a broad maximum during wintertime that is associated with the previous summers freshwater moving through Hudson Strait from southern Hudson Bay. Tidally driven mixing is shown to have a strong effect on the modeled ice-ocean circulation. 相似文献
5.
FGOALS_gg1.1极地气候模拟 总被引：4，自引：0，他引：4
对中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室发展的气候系统模式FGOALS_g1.1的极地气候模拟现状进行了较为全面的评估.结果表明,FGOALS_g1.1对南北极海冰的主要分布特征、季节变化和年代际变化趋势具有一定的模拟能力.但也注意到,与观测相比,模式存在以下几方面的问题:(1)模拟的海冰总面积北极偏多,而南极偏少.北极,北大西洋海冰全年明显偏多;夏季,西伯利亚沿海海冰偏多,而波弗特海海冰偏少.南极,威德尔海和罗斯海冬季海冰偏少.南北极海冰边缘都存在异常的较大范围密集度很小的碎冰区,夏季尤为显著.(2)海冰流速在南北极海冰边缘和南极大陆沿岸附近较大.北极,模式没能模拟出波弗特涡流,并且由于模式网格中北极点的处理问题,造成其附近错误的海冰流场及厚度分布.这些海冰偏差与模式模拟的大气和海洋状况有着密切的联系.进一步分析表明,FGOALS_g1.1模拟的冰岛低压和南极绕极西风带明显偏弱,其通过大气环流和海表面风应力影响向极地的热量输送,在很大程度上导致上述的海冰偏差.此外,耦合模式中大气-海冰-海洋的相互作用可以放大子模式中的偏差. 相似文献
6.
利用1951-2013年广西90个气象观测站气温资料、国家气候中心74项指数和美国National Oceanic and Atmospheric Administration（NOAA）的Climate Prediction Center（CPC）60项指数以及海温和陆地雪盖资料、美国国家冰雪研究中心（NSIDC）的两极海冰资料,使用相关分析方法得到广西寒露风开始期气候影响因子,利用逐步回归和神经网络方法进行寒露风开始期的预测。结果表明：寒露风开始期与前一年9-10月北极海冰面积、当年3月南极海冰面积、前一年6月欧亚雪盖、当年5月北美雪盖、北半球雪盖的相关显著。与前一年9月北半球极涡面积指数、前一年10月亚洲区极涡面积指数、前一年3月热带印度洋海温偶极子等指数相关显著。粒子群-神经网络方法预测误差低于逐步回归方法,预报能力有明显提高。 相似文献
7.
Long-term observations for monitoring of the cryosphere 总被引：1，自引：0，他引：1
John E. Walsh 《Climatic change》1995,31(2-4):369-394
Variations of the cryosphere over decadal-to-century timescales are assessed by a survey of data on sea ice, snow cover, glaciers and ice sheets, permafrost and lake ice. The recent variations are generally consistent across the different cryospheric variables, especially when placed into the context of variations of temperature and precipitation. The recent warming over northern land areas has been accompanied by a decrease of snow cover, particularly during spring; the retreat of mountain glaciers is, in an aggregate sense, compatible with the observed warming; permafrost extent and lake ice duration show similar variations in areas for which data are available. Corresponding trends are not apparent, however, in data for some regions such as eastern Canada, nor in hemispheric sea ice data, especially for winter. The data also suggest an increase of snowfall over high latitudes, including the Antarctic ice sheet.Estimates of both the climatic and the statistical significance of the recent variations are hampered by data inhomogeneities, the shortness of the records of many variables and the absence of central archives for data on several variables. The potential of monitoring by satellite remote sensing has been realized with several variables (extent of sea ice, snow cover). Other cryospheric variables (snow depth, ice sheet elevation, lake ice, mountain glaciers) may be amenable to routine monitoring by satellites pending advances in instrumentation, modifications of satellite orbit, and further developments in signal detection algorithms. The survey of recent variations leads to recommendations concerning the use of historical data,in situ measurements, and remote sensing applications in the monitoring of the cryosphere. 相似文献
8.
Actual and insolation-weighted Northern Hemisphere snow cover and sea ice are binned by latitude bands for the years 1973–2002. Antarctic sea-ice is also analyzed for the years 1980–2002. The use of insolation weighting provides an improved estimate of the radiative feedbacks of snow cover and sea-ice into the atmosphere. One conclusion of our assessment is that while a decrease in both areal and insolation-weighted values have occurred, the data does not show a monotonic decrease of either Arctic sea-ice or Northern Hemisphere snow cover. If Arctic perennial sea-ice is decreasing since the total reduction in areal coverage is relatively small, a large portion of it is being replenished each year such that its radiative feedback to the atmosphere is muted. Antarctic sea-ice areal cover shows no significant long-term trend, while there is a slight decrease in the insolation-weighted values for the period 1980–2002. From the early 1990s to 2001, there was a slight increase in both values. The comparison of general circulation model simulations of changes over the last several decades to observed changes in insolation-weighted sea-ice and snow cover should be a priority research topic. 相似文献
9.
Qinghua YANG Jiping LIU Matti LEPPRANTA Qizhen SUN Rongbin LI Lin ZHANG Thomas JUNG Ruibo LEI Zhanhai ZHANG Ming LI Jiechen ZHAO Jingjing CHENG 《大气科学进展》2016,33(5):535-543
The snow/sea-ice albedo was measured over coastal landfast sea ice in Prydz Bay, East Antarctica(off Zhongshan Station)during the austral spring and summer of 2010 and 2011. The variation of the observed albedo was a combination of a gradual seasonal transition from spring to summer and abrupt changes resulting from synoptic events, including snowfall, blowing snow, and overcast skies. The measured albedo ranged from 0.94 over thick fresh snow to 0.36 over melting sea ice. It was found that snow thickness was the most important factor influencing the albedo variation, while synoptic events and overcast skies could increase the albedo by about 0.18 and 0.06, respectively. The in-situ measured albedo and related physical parameters(e.g., snow thickness, ice thickness, surface temperature, and air temperature) were then used to evaluate four different snow/ice albedo parameterizations used in a variety of climate models. The parameterized albedos showed substantial discrepancies compared to the observed albedo, particularly during the summer melt period, even though more complex parameterizations yielded more realistic variations than simple ones. A modified parameterization was developed,which further considered synoptic events, cloud cover, and the local landfast sea-ice surface characteristics. The resulting parameterized albedo showed very good agreement with the observed albedo. 相似文献
10.
M. V. Bukharov 《Russian Meteorology and Hydrology》2013,38(1):35-43
Analyzed is the interrelation between the properties of the sea ice, its scattering index at the frequencies of 23 and 31 GHz, and the brightness temperature computed from the multispectral measurements with the AMSU radiometer. Within the frameworks of the simplified model representations, the quantitative estimates are obtained of the influence of the ice thickness, ice concentration, and presence of inhomogeneities in the emitting layer and snow cover on the ice surface on the ice scattering index values. It is demonstrated that the scattering on the dislocations formed near the surface of ice at its bend and compression can be the main reason for the rapid change in the scattering index of one-year and old ice observed in different seasons. The results of the analysis corroborated the validity of applying the scattering index for the revelation of the areas of deformation and hummocking of sea ice, as well as for the estimation of the age and thickness of thin and young ice. 相似文献
11.
Abstract Present‐day results and CO2 sensitivity are described for two versions of a global climate model (genesis) with and without sea‐ice dynamics. Sea‐ice dynamics is modelled using the cavitating‐fluid method of Flato and Hibler (1990, 1992). The atmospheric general circulation model originated from the NCAR Community Climate Model version 1, but is heavily modified to include new treatments of clouds, penetrative convection, planetary boundary‐layer mixing, solar radiation, the diurnal cycle and the semi‐Lagrangian transport of water vapour. The surface models include an explicit model of vegetation (similar to BATS and SiB), multilayer models of soil, snow and sea ice, and a slab ocean mixed layer. When sea‐ice dynamics is turned off, the CO2‐induced warming increases drastically around ～60–80°S in winter and spring. This is due to the much greater (and unrealistic) compactness of the Antarctic ice cover without dynamics, which is reduced considerably when CO2 is doubled and exposes more open ocean to the atmosphere. With dynamics, the winter ice is already quite dispersed for 1 × CO2 so that its compactness does not decrease as much when CO2 is doubled. 相似文献
12.
利用青海省甘德两次降雪过程的微气象观测数据,探讨了两场降雪过程雪深、雪密度、雪中含冰量、雪中含水量和雪面温度的变化情况,分析了地表反照率与雪密度、雪中含冰量及雪中含水量的关系,结合降雪过程近地面温、湿、风廓线特征分析了积雪对近地面温、湿、风梯度的影响。结果表明:积雪覆盖会导致地表反照率显著增加,降雪过后正午时地表反照率可高达0.8～0.9。随着积雪的消融,地表反照率逐渐减小;积雪反照率与雪密度和雪中含冰量呈正相关,与雪中含水量呈负相关;地表积雪覆盖会导致近地面温度梯度绝对值减小,相对湿度梯度绝对值在凌晨减小、午后增大,地表积雪覆盖对近地面风速梯度变化并无特定的影响。 相似文献
13.
The origin of Antarctic precipitation: a modelling approach 总被引：3，自引：0，他引：3
GILLES DELAYGUE VALÉRIE MASSON JEAN JOUZEL RANDAL D. KOSTER RICHARD J. HEALY 《Tellus. Series B, Chemical and physical meteorology》2000,52(1):19-36
The contribution of different moisture sources to Antarctic precipitation for present‐day and glacial conditions is estimated with the NASA/GISS Atmospheric General Circulation Model. Despite its low horizontal resolution (8°×10°), this model simulates reasonably well the broad features of the observed present‐day hydrological cycle. Simulated present‐day Antarctic precipitation is dominated throughout the year by moisture from a subtropical/midlatitude band (30°S−60°S). The moisture supplied to a given coastal area of Antarctica originates mostly in the adjacent oceanic basin; closer to the pole, other oceanic basins can also contribute significantly. Replacing the present‐day sea surface temperatures (SSTs) and sea ice cover in the GCM with those from the CLIMAP oceanic reconstruction for the last glacial maximum (LGM), greatly increases the simulated latitudinal temperature gradient, with the consequence of slightly enhancing the contribution of low latitude moisture to Antarctic precipitation. It also changes the seasonality of the different contributions and thus their budget, particularly in coastal regions. Because the nature of LGM tropical SSTs is still under debate, we performed an additional LGM simulation in which the tropical SSTs are reduced relative to those of CLIMAP. The resulting decrease in the latitudinal gradient brings the relative contributions to Antarctic precipitation more in line with those of the present‐day simulation. 相似文献
14.
气候监测诊断是了解气候系统变化及其成因的重要手段。经过二十多年的发展,目前国家气候中心建立了一套多时间、多空间尺度的气候系统监测诊断业务系统,并且在业务应用中不断发展和完善。同时,加强了关键异常信号及其对我国气候异常的影响机理的研究,在海温、冰雪、土壤温湿度、大气低频振动、北极涛动、季风、平流层异常等对我国气候影响的监测诊断等方面提出一些新理论、新技术和新方法,并在业务中得以应用。本文回顾了近20年来我国气候监测诊断业务的发展历程,介绍了我国气候监测诊断业务的技术现状,重点总结了近些年来在实时气候监测诊断业务中发展和应用的一些新技术和气候异常机理。 相似文献
15.
Kirsti Jylhä Stefan Fronzek Heikki Tuomenvirta Timothy R. Carter Kimmo Ruosteenoja 《Climatic change》2008,86(3-4):441-462
Changes in indices related to frost and snow in Europe by the end of the twenty-first century were analyzed based on experiments
performed with seven regional climate models (RCMs). All the RCMs regionalized information from the same general circulation
model (GCM), applying the IPCC-SRES A2 radiative forcing scenario. In addition, some simulations used SRES B2 radiative forcing
and/or boundary conditions provided by an alternative GCM. Ice cover over the Baltic Sea was examined using a statistical
model that related the annual maximum extent of ice to wintertime coastal temperatures. Fewer days with frost and snow, shorter
frost seasons, a smaller liquid water equivalent of snow, and milder sea ice conditions were produced by all model simulations,
irrespective of the forcing scenario and the driving GCM. The projected changes have implications across a diverse range of
human activities. Details of the projections were subject to differences in RCM design, deviations between the boundary conditions
of the driving GCMs, uncertainties in future emissions and random effects due to internal climate variability. A larger number
of GCMs as drivers of the RCMs would most likely have resulted in somewhat wider ranges in the frost, snow and sea ice estimates
than those presented in this paper. 相似文献
16.
THE MICROPHYSICAL STRUCTURE OF SNOW CLOUDS AND THE GROWTH PROCESS OF SNOW PARTICLES IN WINTER IN XINJIANG 
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下载免费PDF全文 The microphysical structure of snow clouds and the growth process of snow crystals were observed by means of instrumented aircraft,weather radar,snow crystal observations etc.in Urumqi region during the winter of 1982.The analysis of three cases show that about 70% of snow mass growth is produced in the lower layer below 2000 m under the cold front,and that the concentration of ice crystals is as high as 60 L-1 and the supercooled water is absent in lower clouds.We may infer that the deposition of ice crystals and the aggregation of snow crystals are important processes for the snow development.The microphysical structure of the snow band near the front aloft and its characteristics as a seeder cloud are also described in this paper. 相似文献
17.
Response of the Antarctic ice sheet to future greenhouse warming 总被引：2，自引：0，他引：2
Possible future changes in land ice volume are mentioned frequently as an important aspect of the greenhouse problem. This paper deals with the response of the Antarctic ice sheet and presents a tentative projection of changes in global sea level for the next few hundred years, due to changes in its surface mass balance. We imposed a temperature scenario, in which surface air temperature rises to 4.2° C in the year 2100 AD and is kept constant afterwards. As GCM studies seem to indicate a higher temperature increase in polar latitudes, the response to a more extreme scenario (warming doubled) has also been investigated. The mass balance model, driven by these temperature perturbations, consists of two parts: the accumulation rate is derived from present observed values and is consequently perturbed in proportion to the saturated vapour pressure at the temperature above the inversion layer. The ablation model is based on the degree-day method. It accounts for the daily temperature cycle, uses a different degree-day factor for snow and ice melting and treats refreezing of melt water in a simple way. According to this mass balance model, the amount of accumulation over the entire ice sheet is presently 24.06 × 1011 m3 of ice, and no runoff takes place. A 1°C uniform warming is then calculated to increase the overall mass balance by an amount of 1.43 × 1011 m3 of ice, corresponding to a lowering of global sea level with 0.36 mm/yr. A temperature increase of 5.3°C is needed for the increase in ablation to become more important than the increase in accumulation and the temperature would have to rise by as much as 11.4°C to produce a zero surface mass balance. Imposing the Bellagio-scenario and accumulating changes in mass balance forward in time (static response) would then lower global sea level by 9 cm by 2100 AD. In a subsequent run with a high-resolution 3-D thermomechanic model of the ice sheet, it turns out that the dynamic response of the ice sheet (as compared to the direct effect of the changes in surface mass balance) becomes significant after 100 years or so. Ice-discharge across the grounding-line increases, and eventually leads to grounding-line retreat. This is particularly evident in the extreme case scenario and is important along the Antarctic Peninsula and the overdeepened outlet glaciers along the East Antarctic coast. Grounding-line retreat in the Ross and Ronne-Filchner ice shelves, on the other hand, is small or absent. 相似文献
18.
东北冷涡中尺度云系降水机制研究 II: 数值模拟 总被引：1，自引：1，他引：0
在利用卫星、雷达和机载PMS(粒子测量系统)等观测资料对2003年7月8日东北冷涡积层混合云系的降水形成机制分析的基础上,将观测分析与数值模拟研究相结合,用中尺度数值模式对积层混合云系做数值模拟,并结合观测资料进一步分析了积层混合云系的微物理结构、粒子形成过程和降水形成机制,获得如下结果:(1)混合云中对流云具有分层的微物理结构.冰晶含水量最大值出现的高度最高,其次由高到低的排序是雪、云水、霰和雨;雨水主要出现在云的暖区;各种粒子中以雨水含水量最高,其次是霰.对流云体生命期较长,微物理结构基本稳定.(2)粒子形成增长过程有差异.冰晶通过凝华过程增长.雪主要来源于冰晶,产生后主要通过撞冻、收集冰晶和凝华过程增长,其中撞冻过冷云水增长对雪质量贡献最大,其产生率极大值高度与过冷云水相当.丰富的过冷云水,给雪的撞冻增长提供了有利条件.在高、中和低层雪的形成有着不同的机制,高层雪收集冰晶长大后,下落到低层又以雪撞冻过冷云水的结淞增长为主要过程.霰主要由雨滴冻结和雪的转化产生,过冷雨滴与冰晶接触冻结成霰;过冷雨滴收集雪,雪随着雨滴的冻结而转化成霰.因此霰的产生与过冷雨滴关系极大.霰主要撞冻云水、收集雪和冰晶增长,其中撞冻是霰的重要增长过程.雨水主要由霰的融化形成,降水主要是由冷云过程产生的.在过冷层,霰撞冻增长占优势.云上部的冰晶和雪对云的中部具有播撒作用,过冷层中存在丰富的过冷水,对冰相粒子的撞冻增长有利.对云水消耗的分析表明,雨滴对云滴的收集、霰和雪对云水的撞冻增长是消耗云水的主要过程.(3)从各种粒子的形成和增长过程可以看出,大部分雨水由霰融化形成,暖云过程贡献要小得多.可见,降水主要是由冷云过程产生的,这与观测分析的结果一致. 相似文献
19.
André April 《大气与海洋》2014,52(5):384-397
Ocean convection in the Antarctic has been studied many times and has been revealed to be responsible for ice-cover reduction. In the Arctic, proof of that phenomenon has not been documented. It is believed that this phenomenon happens on a smaller scale in the Arctic when local circulation of deep warmer water melts and slows ice production. An example of this is the North Water (NOW) polynya in northern Baffin Bay. A polynya is an area of open water in an otherwise ice-covered area. As ice forms under the fast ice near the boundary of the polynya, ocean salts (brine) are ejected from the newly formed ice. This water, which has an increased concentration of salt, sinks and is replaced by warmer water from below, and this slows ice formation. In our study a coupled one-dimensional thermodynamic snow–fast ice model incorporating ocean heat flux input via a shallow convection model was used. Ice thickness was calculated using a thermodynamic model that included a current-induced entrainment model and a convection model to account for brine rejection during ice growth. Atmospheric observations from Grise Fiord and Thule and ocean profiles around the NOW polynya near these sites were used as input to the model. This purely thermodynamic study enables us to obtain ice thickness values that can be compared with qualitative observations. This modelling study compares two sites related to the NOW polynya. The results indicate that the shallow convection model simulates the reduction of fast ice near Thule but not near Grise Fiord. 相似文献
20.
南极海冰首要模态呈现偶极子型异常,正负异常中心分别位于别林斯高晋海/阿蒙森海和威德尔海。过去研究表明冬春季节南极海冰涛动异常对后期南极涛动（Antarctic Oscillation,AAO）型大气环流有显著影响,而AAO可以通过经向遥相关等机制影响北半球大气环流和东亚气候。本文中我们利用观测分析发现南极海冰涛动从5～7月（May–July,MJJ）到8～10月（August–October, ASO）有很好的持续性,并进一步分析其对北半球夏季大气环流的可能影响及其物理过程。结果表明,MJJ南极海冰涛动首先通过冰气相互作用在南半球激发持续性的AAO型大气环流异常,使得南半球中纬度和极地及热带之间的气压梯度加大,在MJJ至JAS,纬向平均纬向风呈现显著的正负相间的从南极到北极的经向遥相关型分布。对流层中层位势高度场上,在澳大利亚北部到海洋性大陆区域,出现显著的负异常,在东亚沿岸从低纬到高纬呈现南北走向的“? + ?”太平洋—日本（Pacific–Japan,PJ）遥相关波列,其对应赤道中部太平洋及赤道印度洋存在显著的降水和海温负异常,西北太平洋至我国东部沿海地区存在显著降水正异常和温度负异常;低纬度北美洲到大西洋一带存在的负位势高度异常和北大西洋附近存在的正位势高度异常中心,构成一个类似于西大西洋型遥相关（Western Atlantic,WA）的结构,对应赤道南大西洋降水增加和南撒哈拉地区降水减少。从物理过程来看,南极海冰涛动首先通过局地效应影响Ferrel环流,进而通过经圈环流调整使得海洋性大陆区域和热带大西洋上方的Hadley环流上升支得到增强,海洋性大陆区域特别是菲律宾附近的热带对流活动偏强,激发类似于负位相的PJ波列,影响东亚北太平洋地区的大气环流,而热带大西洋对流增强和北传特征,则通过激发WA遥相关影响大西洋和欧洲地区的大气环流。以上两种通道将持续性MJJ至ASO南极海冰涛动强迫的大气环流信号从南半球中高纬度经热带地区传递到北半球中高纬地区,从而对热带和北半球夏季大气环流产生显著影响。 相似文献