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1.
Ralph Markson 《Pure and Applied Geophysics》1971,84(1):161-200
Summary The basic thesis of this paper is that the proper scope of meteorology should include, besides the earth's atmosphere, the sun's atmosphere (the solar corona), the associated interplanetary magnetic field, and lunar modulation of this environment. Recent advances in space science have enabled us to make direct measurements in this region for the first time. The shape and characteristics of the magnetosphere have been completely redefined during the last ten years from a simple magnetic dipole to the present model with an elongated tail stretched out by the solar wind. The interplanetary magnetic field has been defined with its spiral structure and sectors tied into the solar surface. This provides a magnetic link between the sun and earth. It is probable that extra-terrestrial factors do play a role in regulating weather, although the extent of this influence remains to be determined. Possibly such effects are most significant or easily detectable in the realm of atmospheric electricity. In view of the limitations in our present knowledge of all the variables responsible for regulating weather, it would seem appropriate to pursue the study of extra-terrestrial influences. Such research could lead to a better understanding of atmospheric circulation, precipitation mechanisms and thunderstorms. The field of meteorology which might particularly benefit from such research is long range weather forecasting. 相似文献
2.
Synoptic Classification and Establishment of Analogues with Artificial Neural Networks 总被引：1，自引：0，他引：1
Weather charts depicting the spatial distribution of various meteorological parameters constitute an indispensable pictorial tool for meteorologists, in diagnosing and forecasting synoptic conditions and the associated weather. The purpose of the present research is to investigate whether training artificial neural networks can be employed in the objective identification of synoptic patterns on weather charts. In order to achieve this, the daily analyses at 0000UTC for 1996 were employed. The respective data consist of the grid-point values of the geopotential height of the 500 hPa isobaric level in the atmosphere. A uniform grid-point spacing of 2.5° × 2.5° is used and the geographical area covered by the investigation lies between 25°N and 65°N and between 20°W and 50°E, covering Europe, the Middle East and the Northern African Coast. An unsupervised learning self-organizing feature map algorithm, namely the Kohonen's algorithm, was employed. The input consists of the grid-point data described above and the output is the synoptic class which each day belongs to. The results referred to in this study employ the generation of 15 and 20 synoptic classes (more classes have been investigated but the results are not reported here). The results indicate that the present technique produced a satisfactory classification of the synoptic patterns over the geographical region mentioned above. Also, it is revealed that the classification performed in this study exhibits a strong seasonal relationship. 相似文献
3.
Conditional nonlinear optimal perturbation: Applications to stability,sensitivity, and predictability 总被引：4，自引：0，他引：4
Conditional nonlinear optimal perturbation (CNOP) is a nonlinear generalization of linear singular vector (LSV) and features
the largest nonlinear evolution at prediction time for the initial perturbations in a given constraint. It was proposed initially
for predicting the limitation of predictability of weather or climate. Then CNOP has been applied to the studies of the problems
related to predictability for weather and climate. In this paper, we focus on reviewing the recent advances of CNOP’s applications,
which involves the ones of CNOP in problems of ENSO amplitude asymmetry, block onset, and the sensitivity analysis of ecosystem
and ocean’s circulations, etc. Especially, CNOP has been primarily used to construct the initial perturbation fields of ensemble
forecasting, and to determine the sensitive area of target observation for precipitations. These works extend CNOP’s applications
to investigating the nonlinear dynamical behaviors of atmospheric or oceanic systems, even a coupled system, and studying
the problem of the transition between the equilibrium states. These contributions not only attack the particular physical
problems, but also show the superiority of CNOP to LSV in revealing the effect of nonlinear physical processes. Consequently,
CNOP represents the optimal precursors for a weather or climate event; in predictability studies, CNOP stands for the initial
error that has the largest negative effect on prediction; and in sensitivity analysis, CNOP is the most unstable (sensitive)
mode. In multi-equilibrium state regime, CNOP is the initial perturbation that induces the transition between equilibriums
most probably. Furthermore, CNOP has been used to construct ensemble perturbation fields in ensemble forecast studies and
to identify sensitive area of target observation. CNOP theory has become more and more substantial. It is expected that CNOP
also serves to improve the predictability of the realistic predictions for weather and climate events plays an increasingly
important role in exploring the nonlinear dynamics of atmospheric, oceanic and coupled atmosphere-ocean system.
Supported by National Basic Research Program of China (Grant Nos. 2006CB403606, 2007CB411800), National Natural Science Foundation
of China (Grant Nos. 40830955, 40675030, 40505013), Institute of Atmospheric Physics, Chinese Academy of Sciences (Grant No.
IAP07202), and LASG State Key Laboratory Special Fund 相似文献
4.
Meteorological conditions for the persistent severe fog and haze event over eastern China in January 2013 总被引：11，自引：0，他引：11
In January 2013,a severe fog and haze event(FHE)of strong intensity,long duration,and extensive coverage occurred in eastern China.The present study investigates meteorological conditions for this FHE by diagnosing both its atmospheric background fields and daily evolution in January 2013.The results show that a weak East Asian winter monsoon existed in January2013.Over eastern China,the anomalous southerly winds in the middle and lower troposphere are favorable for more water vapor transported to eastern China.An anomalous high at 500 hPa suppresses convection.The weakened surface winds are favorable for the fog and haze concentrating in eastern China.The reduction of the vertical shear of horizontal winds weakens the synoptic disturbances and vertical mixing of atmosphere.The anomalous inversion in near-surface increases the stability of surface air.All these meteorological background fields in January 2013 were conducive to the maintenance and development of fog and haze over eastern China.The diagnosis of the daily evolution of the FHE shows that the surface wind velocity and the vertical shear of horizontal winds in the middle and lower troposphere can exert dynamic effects on fog and haze.The larger(smaller)they are,the weaker(stronger)the fog and haze are.The thermodynamic effects include stratification instability in middle and lower troposphere and the inversion and dew-point deficit in near-surface.The larger(smaller)the stratification instability and the inversion are,the stronger(weaker)the fog and haze are.Meanwhile,the smaller(larger)the dewpoint deficit is,the stronger(weaker)the fog and haze are.Based on the meteorological factors,a multi-variate linear regression model is set up.The model results show that the dynamic and thermodynamic effects on the variance of the fog and haze evolution are almost the same.The contribution of the meteorological factors to the variance of the daily fog and haze evolution reaches 0.68,which explains more than 2/3 of the variance. 相似文献
5.
《中国科学:地球科学(英文版)》2017,(11)
This paper reviews the historic understanding of the predictability of atmospheric and oceanic motions, and interprets it in a general framework. On this basis, the existing challenges and unsolved problems in the study of the intrinsic predictability limit(IPL) of weather and climate events of different spatio-temporal scales are summarized. Emphasis is also placed on the structure of the initial error and model parameter errors as well as the associated targeting observation issue. Finally, the predictability of atmospheric and oceanic motion in the ensemble-probabilistic methods widely used in current operational forecasts are discussed.The necessity of considering IPLs in the framework of stochastic dynamic systems is also addressed. 相似文献
6.
Long-term meteorological observation series are fundamental for reflecting climate changes.However,almost all meteorological stations inevitably undergo relocation or changes in observation instruments,rules,and methods,which can result in systematic biases in the observation series for corresponding periods.Homogenization is a technique for adjusting these biases in order to assess the true trends in the time series.In recent years,homogenization has shifted its focus from the adjustments to climate mean status to the adjustments to information about climate extremes or extreme weather.Using case analyses of ideal and actual climate series,here we demonstrate the basic idea of homogenization,introduce new understanding obtained from recent studies of homogenization of climate series in China,and raise issues for further studies in this field,especially with regards to climate extremes,uncertainty of the statistical adjustments,and biased physical relationships among different climate variables due to adjustments in single variable series. 相似文献
7.
Andrew Orr Edward Hanna Julian C.R. Hunt John Cappelen Konrad Steffen AG Stephens 《Pure and Applied Geophysics》2005,162(10):1747-1778
The main characteristic features of stable atmospheric flows over a large mountain plateau are summarised and then compared with mesoscale and synoptic scale numerical simulation, meteorological analysis, satellite imagery, and surface observations for the cases of flows over Southern Greenland for four wind directions. The detailed features are identified using the concepts and scaling of stably stratified flow over large mountains with variations in surface roughness, elevation, and heating. For westerly and easterly winds detached jets form at the southern tip, where coastal jets converge, which propagate large distances across the ocean. Near coasts katabatic winds can combine with barrier jets and wake flows generated by synoptic winds. Note how the approach flow rises/falls over southern Greenland for easterly/westerly winds, leading in both cases to more cloud on the western side. Some conclusions are drawn about the large-scale influences of these flows; detached jets in the atmosphere; air-sea interaction; formation of low pressure systems. For accurate simulations of these flows, mesoscale models are necessary with resolutions of order of 20 km or less. 相似文献
8.
9.
《中国科学:地球科学(英文版)》2015,(3)
Ensemble forcasting,originally developed for weather prediction,is lately being extended to atmospheric dispersion applications,which is a new,effective methodology for improving the atmospheric dispersion numerical modeling.In March 2011,due to the massive 9.0 earthquakes and ensuing tsunami that struck off the northern coast of the island of Honshu,the Fukushima Nuclear Plant I had the substantial leak of radioactive materials into surrounding environment and atmosphere.To aim at the global dispersion modeling of atmospheric radionuclides from Fukushima Nuclear Accident,this paper presents two approaches of atmospheric dispersion forecasting:ensemble dispersion modeling(EDM) and deterministic dispersion modeling(DDM),conducts the globally dispersion modeling cases for Fukushima nuclear accident,and analyzes and evaluates the simulation results using observation data.In this paper,EDM includes three different perturbation methods:meteorological perturbation method,turbulence perturbation method,and physical parameterization ensemble forecasting method.The simulation results show that the trajectories from EDM have a better performance,which is in better agreement with the atmospheric circulation and observation data; the spread from DDM is slower and not as far as EDM.Additionally,the results from EDM display a better performance in the modeling of transport from Japan to China East Sea on April 4.The reasons for these results are:the techniques of MET and TUR are performed by adding perturbations on mean wind and turbulent velocity,respectively; the various different flow fields will result in far spreading in horizontal and the simulation results closer to observation; PHY is performed by using different diffusion physical parameterizations and produces the perturbations on vertical wind,which results the spreading in smaller range and discontinuous in horizontal.Finally,the comparative analysis between modeling results and observation data shows that all cases results are in good agreement with trends of observed radionuclides surface concentration; however,the modeling surface concentration is smaller than observation,especially in DDM and PHY.Furthermore,the EDM results show that MET and TUR are of more evolutionary advantage than PHY in modeling of average and maximum concentration.Therefore,this study can serve as a reference to atmospheric dispersion and environmental emergency response(EER). 相似文献
10.
Influence of land evapotranspiration on climate variations 总被引：1，自引：0，他引：1
A coupled numerical model of the global atmosphere with a qualified biosphere (GOALS/LASG) has been used to assess the nature
of the physical mechanisms for land-atmosphere interactions, and the impacts of the Asian/North American land-surface evapotranspiration
on the regional and global climate. This sensitivity study suggests that the simulated climate would be relatively sensitive
to land surface evapotranspiration, especially over the Asian regions. The removal of evapotranspiration in Asia would create
a warmer and drier climate to a certain degree. Furthermore, the surface evapotranspiration anomalies would make a substantial
contribution to the formation and variation of subtropical anticyclones through the changes in monsoon precipitation and the
β -effect, but also make a large contribution to the variations of the atmospheric circulation in the Northern Hemisphere
and even the globe. Therefore, besides the traditional perception that we have generally emphasized on the influence of subtropical
anticyclones activities on the boreal summer precipitation over the regions of eastern China, the surface evapotranspiration
anomalies, however, also have substantial impacts on the subtropical anticyclones through the changes in monsoon precipitation.
For this reason, the variation in the internal heating sources of the atmosphere caused by the land surface evapotranspiration
and the vapor phase change during the boreal summer is an important external factor forcing the weather and climate. 相似文献
11.
Evaluation of dynamically downscaled reanalysis precipitation data for hydrological application 
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下载免费PDF全文 Skilful and reliable precipitation data are essential for seasonal hydrologic forecasting and generation of hydrological data. Although output from dynamic downscaling methods is used for hydrological application, the existence of systematic errors in dynamically downscaled data adversely affects the skill of hydrologic forecasting. This study evaluates the precipitation data derived by dynamically downscaling the global atmospheric reanalysis data by propagating them through three hydrological models. Hydrological models are calibrated for 28 watersheds located across the southeastern United States that is minimally affected by human intervention. Calibrated hydrological models are forced with five different types of datasets: global atmospheric reanalysis (National Centers for Environmental Prediction/Department of Energy Global Reanalysis and European Centre for Medium‐Range Weather Forecasts 40‐year Reanalysis) at their native resolution; dynamically downscaled global atmospheric reanalysis at 10‐km grid resolution; stochastically generated data from weather generator; bias‐corrected dynamically downscaled; and bias‐corrected global reanalysis. The reanalysis products are considered as surrogates for large‐scale observations. Our study indicates that over the 28 watersheds in the southeastern United States, the simulated hydrological response to the bias‐corrected dynamically downscaled data is superior to the other four meteorological datasets. In comparison with synthetically generated meteorological forcing (from weather generator), the dynamically downscaled data from global atmospheric reanalysis result in more realistic hydrological simulations. Therefore, we conclude that dynamical downscaling of global reanalysis, which offers data for sufficient number of years (in this case 22 years), although resource intensive, is relatively more useful than other sources of meteorological data with comparable period in simulating realistic hydrological response at watershed scales. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
12.
H. Christer Morales 《Pure and Applied Geophysics》1980,119(3):658-676
Summary In connection with an invasion of cold air from the north over the Sudan in April 1973, a major dust storm or rather, a dust storm complex, passed over most of the Sudan.The weather development during this dust storm period is described and illustrated in detail with the aid of synoptic weather and visibility maps, as well as time sections based on SYNOP, METAR, and radiosonde reports from Sudanese meteorological stations.With the aid of the synoptic maps it has been possible to follow the development and movement of the dust storm complex and its relation to the cold fronts preceding the cold air invasion, to the intertropical front (ITF), and to thunderstorm highs which developed within the monsoon air south of the ITF during the initial stage. It was also possible to follow the latitudinal displacements of the ITF, which were caused by the weather systems and associated pressure changes in the harmattan and the monsoon air masses on both sides of it.At the beginning of the dust storm the cold fronts from the north were fairly distinct, but they gradually lost their frontal character. The cold air advection, however, gave rise to increased instability in the lower atmospheric layers, which facilitated the development of dust storms. Eventually the cold fronts merged with the ITF, which, on the other hand, constituted a sharp demarcation line between the harmattan and the monsoon air masses during the whole period, particularly with regard to the air borne dust. From the time sections and the synoptic maps it is evident that the discrepancy in concentration of air borne dust was very sharp along the ITF, particularly during the latter part of the dust storm period. When the ITF slowed down and eventually approached its southernmost position and, simultaneously, the cold air invasion ceased, the dust accumulated in part in the southeastern areas and was in part drained out of the Sudan to the southwest, passing the Central African Republic. 相似文献
13.
A soil–vegetation–atmosphere transfer model (SVAT), interactions between the soil–biosphere–atmosphere (ISBA) of Météo France, is modified and applied to the Athabasca River Basin (ARB) to model its water and energy fluxes. Two meteorological datasets are used: the archived forecasts from the Meteorological Survey of Canada’s Global Environmental Multiscale Model (GEM) and the European Centre for Mid-range Weather Forecasts global re-analysis (ERA-40), representing spatial scales typical of a weather forecasting model and a global circulation model (GCM), respectively. The original treatment of soil moisture and rainfall in ISBA (OISBA) is modified to statistically account for sub-grid heterogeneity of soil moisture and rainfall to produce new, highly non-linear formulations for surface and sub-surface runoff (MISBA). These new formulations can be readily applied to most existing SVATs. Stand alone mode simulations using the GEM data demonstrate that MISBA significantly improves streamflow predictions despite requiring two fewer parameters than OISBA. Simulations using the ERA-40 data show that it is possible to reproduce the annual variation in monthly, mean annual, and annual minimum flows at GCM scales without using downscaling techniques. Finally, simulations using a simple downscaling scheme show that the better performance of higher resolution datasets can be primarily attributed to improved representation of local variation of land cover, topography, and climate. 相似文献
14.
The accuracy of atmospheric numerical model is important for the prediction of urban air pollution. This study investigated and quantified the uncertainties of meteorological and air quality model during multi-levels air pollution periods. We simulated the air quality of megacity Shanghai, China with WRF/CMAQ (Weather Research and Forecasting model and Community Multiscale Air Quality model) at both non-pollution and heavy-pollution episodes in 2012. The weather prediction model failed to reproduce the surface temperature and wind speed in condition of high aerosol loading. The accuracy of the air quality model showed a clear dropping tendency from good air quality conditions to heavily polluted episodes. The absolute model bias increased significantly from light air pollution to heavy air pollution for SO2 (from 2 to 14%) and for PM10 (from 1 to 33%) in both urban and suburban sites, for CO in urban sites (from 8 to 48%) and for NO2 in suburban sites (from 1 to 58%). A test of applying the Urban Canopy Model scheme to the WRF model showed fairly good improvement on predicting the meteorology field, but less significant effect on the air pollutants (6% for SO2 and 19% for NO2 decease in model bias found only in urban sites). This study gave clear evidence to the sensitivities of the model performance on the air pollution levels. It is suggested to consider this impact as a source for model bias in the model assessment and make improvement in the model development in the future. 相似文献
15.
The Global Atmospheric Electrical Circuit and Climate 总被引：2，自引：1，他引：2
R. G. Harrison 《Surveys in Geophysics》2004,25(5-6):441-484
Evidence is emerging for physical links among clouds, global temperatures, the global atmospheric electrical circuit and cosmic ray ionisation. The global circuit extends throughout the atmosphere from the planetary surface to the lower layers of the ionosphere. Cosmic rays are the principal source of atmospheric ions away from the continental boundary layer: the ions formed permit a vertical conduction current to flow in the fair weather part of the global circuit. Through the (inverse) solar modulation of cosmic rays, the resulting columnar ionisation changes may allow the global circuit to convey a solar influence to meteorological phenomena of the lower atmosphere. Electrical effects on non-thunderstorm clouds have been proposed to occur via the ion-assisted formation of ultra-fine aerosol, which can grow to sizes able to act as cloud condensation nuclei, or through the increased ice nucleation capability of charged aerosols. Even small atmospheric electrical modulations on the aerosol size distribution can affect cloud properties and modify the radiative balance of the atmosphere, through changes communicated globally by the atmospheric electrical circuit. Despite a long history of work in related areas of geophysics, the direct and inverse relationships between the global circuit and global climate remain largely quantitatively unexplored. From reviewing atmospheric electrical measurements made over two centuries and possible paleoclimate proxies, global atmospheric electrical circuit variability should be expected on many timescales. 相似文献
16.
K. A. Nicoll 《Surveys in Geophysics》2012,33(5):991-1057
Measurements of the electrical characteristics of the atmosphere above the surface have been made for over 200?years, from a variety of different platforms, including kites, balloons, rockets and aircraft. From these measurements, a great deal of information about the electrical characteristics of the atmosphere has been gained, assisting our understanding of the global atmospheric electric circuit, thunderstorm electrification and lightning generation mechanisms, discovery of transient luminous events above thunderstorms and many other electrical phenomena. This paper surveys the history of atmospheric electrical measurements aloft, from the earliest manned balloon ascents to current day observations with free balloons and aircraft. Measurements of atmospheric electrical parameters in a range of meteorological conditions are described, including clear air conditions, polluted conditions, non-thunderstorm clouds, and thunderstorm clouds, spanning a range of atmospheric conditions, from fair weather to the most electrically active. 相似文献
17.
Numerical simulation of the influence of aerosol radiation effect on urban boundary layer 总被引：2，自引：0，他引：2
With the intensification of pollution and urbanization, the aerosol radiation effect continues to play an important role in the urban boundary layer. In this paper, a winter pollution process in Beijing has been taken as an example, and a new aerosol vertical profile in the radiative parameterization scheme within the Weather Forecast Research and Forecasting (WRF) model has been updated to study the effect of aerosols on radiation and the boundary layer. Furthermore, the interactions among aerosols, urbanization, and planetary boundary layer (PBL) meteorology were discussed through a series of numerical experiments. The results show the following: (1) The optimization improves the performance of the model in simulating the distribution features of air temperature, humidity, and wind in Beijing. (2) The aerosols reduce the surface temperature by reducing solar radiation and increasing the temperature in the upper layer by absorbing or backscattering solar radiation. The changes in the PBL temperature lead to more stable atmospheric stratification, reducing the energy transfer from the surface and the height of the boundary layer. (3) With the increase in the aerosol optical depth, the atmospheric stratification most likely becomes stable over rural areas, most likely becomes stable over suburb areas, and has great difficultly becoming stable over urban areas. Aerosol radiative forcing, underlying urban surfaces, and the interaction between them are the main factors that affect the changes in the meteorological elements in the PBL. 相似文献
18.
E. Blanc L. Ceranna A. Hauchecorne A. Charlton-Perez E. Marchetti L. G. Evers T. Kvaerna J. Lastovicka L. Eliasson N. B. Crosby P. Blanc-Benon A. Le Pichon N. Brachet C. Pilger P. Keckhut J. D. Assink P. S. M. Smets C. F. Lee J. Kero T. Sindelarova N. Kämpfer R. Rüfenacht T. Farges C. Millet S. P. Näsholm S. J. Gibbons P. J. Espy R. E. Hibbins P. Heinrich M. Ripepe S. Khaykin N. Mze J. Chum 《Surveys in Geophysics》2018,39(2):171-225
19.
The Himalayan region of north India is composed of complex mountain ranges with different altitudes and orientations, causing
prevailing weather conditions to be complex. Wintertime eastward moving synoptic weather systems `Western Disturbances' (WDs)
yield large amounts of precipitation over this region. Numerous micro/mesoscale circulations become generated along with prevailing
weather due to surface heterogeneity and land-use variability of the Himalayan region. WDs along with these circulations may
give rise to very adverse weather conditions over the region. Intraseasonal variability of surface climate over the Himalayas
is studied using regional climate model (RegCM3) with 60 km resolution. A 6-month (Oct. 1999–Mar. 2000) period, as this period
has received an enormous amount of precipitation in the form of snow, is considered to study surface climate variability in
terms of temperature, precipitation and snow amount. Model simulations show cold bias over the Himalayan region and warm bias
over the northwest India. Average monthly distribution of temperature indicates that a controlled experiment could capture
the areas of lowest temperature regime. Precipitation fields could be simulated only up to a certain degree of satisfaction
and the influence of topographic elevation and valleys needs to be seen. RegCM3 provides a representation of resolvable atmospheric
circulations that results in explaining mean variability during winter. 相似文献
20.
人类活动引起全球变暖,衡量全球气候变化的指标有陆地、大气和海洋温度,水汽含量等等.研究对流层底层大气温度和水汽含量变化的传统方法是用数值天气预报模型和微波声纳,尚未实现用全球均匀覆盖的数据来做精确的定量研究.和GNSS系列卫星计划比较,最近发射的COSMIC卫星气象探测数据的空间、时间以及垂直分辨率都大大提高.采用COSMIC数据可以改进和量化南极洲的大气压力模型,并综合GNSS系列卫星测量的水汽和温度剖面研究全球气候变化.用一维协方差算法估计南极洲及附近海洋的大气压、温度和湿度剖面.把COSMIC卫星密集测量期间演算得到的大气折射率和GNSS系列卫星的结果进行比较.再和独立测量数据进行比较,包括南极洲自动气象观测站资料,数值天气预报模型资料,多种测高卫星水汽资料和海洋表面温度资料以及区域GPS水汽图.上述工作将改进发展中的气象遥感技术并应用于天气预报和空间天气预报及全球气候变化研究. 相似文献