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1.
J. A. Kington 《Climatic change》1980,3(1):7-36
An account is given of the preparation of daily weather maps within the historical-instrumental period, with details concerning the detection and location of source material and its subsequent examination, collection and reduction to provide a workable synoptic network of comparable meteorological observations over the eastern North Atlantic-European sector. The application of the Lamb British Isles weather types and Grosswetterlagen for the statistical analysis of circulation patterns derived from these charts is discussed. An objective test was devised whereby the frequency of monthly extremes of nine variables was examined with the following important conclusions:
- the synoptic charts of the 1780s show no evidence of systematic errors when compared with rainfall figures,
- the early 1780s was a period of unusually high climatic variability on the month-to-month time-scale, especially in the frequencies of cyclonic and of anticyclonic days.
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Om Prakash Tripathi Sophie Godin-Beekmann Franck Lefèvre Marion Marchand Andrea Pazmiño Alain Hauchecorne Florence Goutail Hans Schlager C. Michael Volk B. Johnson G. König-Langlo Stefano Balestri Fred Stroh T. P. Bui H. J. Jost T. Deshler Peter von der Gathen 《Journal of Atmospheric Chemistry》2006,55(3):205-226
Simulations of polar ozone losses were performed using the three-dimensional high-resolution (1∘ × 1∘) chemical transport model MIMOSA-CHIM. Three Arctic winters 1999–2000, 2001–2002, 2002–2003 and three Antarctic winters 2001, 2002, and 2003 were considered for the study. The cumulative ozone loss in the Arctic winter 2002–2003 reached around 35% at 475 K inside the vortex, as compared to more than 60% in 1999–2000. During 1999–2000, denitrification induces a maximum of about 23% extra ozone loss at 475 K as compared to 17% in 2002–2003. Unlike these two colder Arctic winters, the 2001–2002 Arctic was warmer and did not experience much ozone loss. Sensitivity tests showed that the chosen resolution of 1∘ × 1∘ provides a better evaluation of ozone loss at the edge of the polar vortex in high solar zenith angle conditions. The simulation results for ozone, ClO, HNO3, N2O, and NO
y
for winters 1999–2000 and 2002–2003 were compared with measurements on board ER-2 and Geophysica aircraft respectively. Sensitivity tests showed that increasing heating rates calculated by the model by 50% and doubling the PSC (Polar Stratospheric Clouds) particle density (from 5 × 10−3 to 10−2 cm−3) refines the agreement with in situ ozone, N2O and NO
y
levels. In this configuration, simulated ClO levels are increased and are in better agreement with observations in January but are overestimated by about 20% in March. The use of the Burkholder et al. (1990) Cl2O2 absorption cross-sections slightly increases further ClO levels especially in high solar zenith angle conditions. Comparisons of the modelled ozone values with ozonesonde measurement in the Antarctic winter 2003 and with Polar Ozone and Aerosol Measurement III (POAM III) measurements in the Antarctic winters 2001 and 2002, shows that the simulations underestimate the ozone loss rate at the end of the ozone destruction period. A slightly better agreement is obtained with the use of Burkholder et al. (1990) Cl2O2 absorption cross-sections. 相似文献
4.
One of the main concerns in regional climate modeling is to which extent limited-area regional climate models (RCM) reproduce
the large-scale atmospheric conditions of their driving general circulation model (GCM). In this work we investigate the ability
of a multi-model ensemble of regional climate simulations to reproduce the large-scale weather regimes of the driving conditions.
The ensemble consists of a set of 13 RCMs on a European domain, driven at their lateral boundaries by the ERA40 reanalysis
for the time period 1961–2000. Two sets of experiments have been completed with horizontal resolutions of 50 and 25 km, respectively.
The spectral nudging technique has been applied to one of the models within the ensemble. The RCMs reproduce the weather regimes
behavior in terms of composite pattern, mean frequency of occurrence and persistence reasonably well. The models also simulate
well the long-term trends and the inter-annual variability of the frequency of occurrence. However, there is a non-negligible
spread among the models which is stronger in summer than in winter. This spread is due to two reasons: (1) we are dealing
with different models and (2) each RCM produces an internal variability. As far as the day-to-day weather regime history is
concerned, the ensemble shows large discrepancies. At daily time scale, the model spread has also a seasonal dependence, being
stronger in summer than in winter. Results also show that the spectral nudging technique improves the model performance in
reproducing the large-scale of the driving field. In addition, the impact of increasing the number of grid points has been
addressed by comparing the 25 and 50 km experiments. We show that the horizontal resolution does not affect significantly
the model performance for large-scale circulation. 相似文献
5.
The Analysis on the Features of the Atmospheric Circulation in Preceding Winters for the Summer Drought and Flooding in the Yangtze And Huaihe River Valley 总被引：12，自引：1，他引：12
ＴｈｅＡｎａｌｙｓｉｓｏｎｔｈｅＦｅａｔｕｒｅｓｏｆｔｈｅＡｔｍｏｓｐｈｅｒｉｃＣｉｒｃｕｌａｔｉｏｎｉｎＰｒｅｃｅｄｉｎｇＷｉｎｔｅｒｓｆｏｒｔｈｅＳｕｍｍｅｒＤｒｏｕｇｈｔａｎｄＦｌｏｏｄｉｎｇｉｎｔｈｅＹａｎｇｔｚｅａｎｄＨｕａｉｈｅＲｉｖｅｒ... 相似文献
6.
A novel scheme to derive optimized circulation pattern classifications for downscaling and forecast purposes 总被引：1，自引：0，他引：1
Summary Many synoptic classifications that have been introduced share the problem of a large within-type variability. Therefore, there is still the need for refinement, especially when aiming to downscale climate model outputs. The objective scheme proposed here has been developed to derive circulation pattern classifications that optimally distinguish between different values of regional weather elements. In comparison with methods that similarly take local and large-scale information into consideration (such as classification and regression trees [CART]), computational demand is relatively low and human input is practically unwarranted. Recognition of individual cases is based upon composites of the large-scale conditions of several different meteorological parameters such as geopotential heights, temperatures and relative humidities. For each local weather element a so-called screening discriminant analysis is conducted selecting those large-scale synoptic variables yielding optimal selectivity. The procedure is basically analogous to a stepwise screening regression. At each stage the predictor field minimizing the RMSE between forecasts and observations together with the previously chosen predictor fields is selected. The procedure is terminated either when a maximal number of predictor fields is reached or when the inclusion of another field does not result in a further decrease of the RMSE. Similarity between mean large-scale conditions and the individual cases that are to be assigned is determined by means of a slightly modified version of the widespread Euclidean distance.Using daily data from 51 climate stations located in the Elbe river catchment in the northeastern part of Germany and the western part of the Czech Republic, the attainable reduction of climatological variances was calculated for a variety of weather elements. Results prove the ability of the scheme to effectively discriminate large-scale circulation patterns with respect to local weather parameters, especially temperatures (skill scores of approx. 80%).When solely accurate discrimination is of interest, a fuzzy variant can be utilized producing even better results. It yields the percentage of each circulation type for a specific case, i.e. day. However, in this case physical insights can not be obtained. 相似文献
7.
An empirical classification of weather types in the Mediterranean Basin and their interrelation with rainfall 总被引：1，自引：1，他引：0
T. Littmann 《Theoretical and Applied Climatology》2000,66(3-4):161-171
Summary This paper presents a classification of weather types in the Mediterranean Basin based on cluster analysis of the daily occurrences
of several surface pressure centers and the subjective identification of 500 hPa trough axis positions (1992–1996). The procedure
results in 20 types that explain 69% of overall pressure center variance and which are consistent with the seasonal succession
of regional circulation. The development of weather types in winter is primarily controlled by the eastward propagation of
barotropic waves while departures from the zonal flow pattern in summer tend to be linked to blocked stationary pools. H1-types
with anticyclonic circulation in the Western Mediterranean and cyclonic flow in the eastern part are well interrelated with
zonal and anticyclonic general weather types in Central Europe. H2-types featuring a weak Azores Anticyclone interrelate with
a variety of meridional circulation types after the Hess and Brezowski (1969) classification. The 20 types explain rainfall
variance in the core Mediterranean regions (as defined by principal components) to a high degree while rainfall variance in
marginal regions is influenced by circulation patterns not being typical for the Mediterranean Basin.
Received January 29, 1999 Revised March 28, 2000 相似文献
8.
P. M. James 《Climate Dynamics》2006,27(2-3):215-231
The frequency of occurrence of persistent synoptic-scale weather patterns over the European and North-East Atlantic regions is examined in a hierarchy of climate model simulations and compared to observational re-analysed data. A new objective method, employing pattern correlation techniques, has been constructed for classifying daily-mean mean-sea-level pressure and 500 hPa geopotential height fields with respect to a set of 29 European weather regime types, based on the widely known subjective Grosswetterlagen (GWL) system of the German Weather Service. The objective method is described and applied initially to ERA40 and NCEP re-analysis data. While the resulting daily Objective-GWL catalogue shows some systematic differences with respect to the subjectively-derived original GWL series, the method is shown to be sufficiently robust for application to climate model output. Ensemble runs from the most recent development of the Hadley Centre’s Global Environmental model, HadGEM1, in atmosphere-only, coupled and climate change scenario modes are analysed with regards to European synoptic variability. All simulations successfully exhibit a wide spread of GWL occurrences across all regime types, but some systematic differences in mean GWL frequencies are seen in spite of significant levels of interdecadal variability. These differences provide a basis for estimating local anomalies of surface temperature and precipitation over Europe, which would result from circulation changes alone, in each climate simulation. Comparison to observational re-analyses shows a clear and significant improvement in the simulation of realistic European synoptic variability with the development and resolution of the atmosphere-only models. 相似文献
9.
Michael V. Kurgansky Aldo Montecinos Victor Villagran Stephen M. Metzger 《Boundary-Layer Meteorology》2011,138(2):285-298
We report on field observations in January 2009 (austral summer) of atmospheric dust devils in the northern part of the Atacama
Desert in South America (≈20◦S). An extremely high level of dust-devil activity over the study site has been observed, dependent on local meteorological
conditions. We found a high correlation between the dust-devil frequency of occurrence and the Obukhov length scale, L, calculated from meteorological gradient measurements, with a clear tendency for this frequency to increase with decreasing
−L. The upper threshold values of −L ≈ 20–30 m, and the 2-m mean wind speed, V
2 ≈ 8m s−1, for dust-devil occurrence have been found, but the minimal V
2 threshold was not observed. Parallel routine meteorological measurements enabled us to calculate the main constituents of
the surface energy balance, to obtain direct estimates of the surface albedo (α ≈ 0.21 at the solar noon) and to summarize the local conditions. 相似文献
10.
天津滨海区50年局地气候变化特征 总被引：18，自引：1，他引：18
利用1951～2000年天津滨海新区的气象资料，分析了50年来气温、降水、日照的变化特征，结果显示天津滨海新区年、冬季、夏季气温均呈上升趋势，20世纪50～80年代冬季增温强于夏季，90年代则夏季升温最为明显；降水总体趋势下降，90年代降到50年来的最小值；年平均日照时数也呈总体下降趋势，90年代下降最为显著。表明天津滨海新区气候正在趋向变暖，特别是近10年来气温急剧升高，降水量锐减、日照时数明显减少，使得高温、干旱、少日照成为天津滨海新区气候的突出问题。 相似文献
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12.
This study has developed sampling downscaling (SmDS), in which dynamical downscaling (DDS) is executed for a few of period selected from a long-term integration by general circulation model based on an observed statistical relationship between large-scale climate and regional-scale precipitation. SmDS expectedly produces climatology and frequency distribution of precipitation over a nested region with reducing computational cost, if a global-scale climate pattern mostly controls regional-scale weather statistics. Here SmDS was attempted for wintertime precipitation over Hokkaido, Japan, because a linkage between snowfall and sea-level pressure patterns has been known by Japanese synopticians and it can be detected by singular value decomposition (SVD) analysis on wintertime inter-annual variability during the period from 1980/1981 to 2009/2010 for precipitation over Hokkaido and moisture flux convergence around there. DDS for the full period over the same domain was also performed for comparison with SmDS. SmDS selected two winters from the top and two winters from the bottom of the projection onto the first SVD mode. It was found that, comparing with the full DDS, SmDS indeed provided unbiased statistics for average but exaggerated extreme statistics such as heavy rainfall frequency. It was also shown that the sampling in the SmDS method was much more effective than the random sampling. 相似文献
13.
The aim of this study was to investigate long-term seasonal trends and decadal change patterns of monthly mean water vapor
pressure (WVP) observation series at 16 meteorological stations scattered point-wisely over the Southeastern Anatolian Project (GAP) area in Turkey, where large-scale soil and water development projects have been put into practice since the 1970s. The record
length of WVP observation series of each station varied between 31- and 41-years between 1962 and 2002. The monthly mean WVP
observation series of each station was rearranged on seasonal basis. Sequential Mann–Kendall trend test, Sen’s slope estimator,
and Spearman’s rank–order correlation tests were employed for detection of likely trends, and Kruskall–Wallis test was used
to detect decadal variations in WVP series of each observation station. A possible area of representation for each meteorological
station was determined by using the Thiessen polygons technique in a geographical information systems media. It was found
that 15 seasonal WVP series have a positive trend covering 97% of the GAP area in the summer season; although one WVP series
has a negative trend direction. However, in the spring season, 33% of the area had a positive trend, and a negative trend
did not appear in any stations. WVP records in the winter season showed an increasing trend over 19% of the GAP area, whereas
a decreasing trend prevailed in 9% of the area. The study results led us to conclude that the substantial increase of WVP
observations in summer season could be attributed to both the shift from rain-fed agriculture to irrigated agriculture being
made increasingly spacious year by year and building large water reservoirs in the GAP located in a semi-arid region. The
results also indirectly suggested that the historical trends in the WVP parameters might be related to global climate change
phenomenon. 相似文献
14.
In order to extend the Tallinn temperature series backward in time, three different climate proxies were used. These were: the first day of ice break-up in Tallinn port, a proxy for the mean winter air temperature (December to March); the first day of ice break-up on the rivers in northern Estonia, a proxy for the beginning of spring; and, the first day of the rye harvest, a proxy for the mean air temperature in spring and summer (April to July). On the basis of these proxies the mean winter temperature could be extended back to the year AD 1500, and the spring and summer temperature back to 1731. The series of winter temperatures was analysed for long-term trends and variations on different timescales. The most striking feature is the warming of the winters from about the mid nineteenth century to the present. The warming is especially noticeable over the latest decades. The climate from the start of the series (AD 1500) to the mid nineteenth century was in general somewhat colder, and should be recognised as a part of the Little Ice Age, though the period was intercepted by warmer winters in the first half of the eighteenth century. 相似文献
15.
Ramzi Touchan Elena Xoplaki Gary Funkhouser Jürg Luterbacher Malcolm K. Hughes Nesat Erkan Ünal Akkemik Jean Stephan 《Climate Dynamics》2005,25(1):75-98
This study represents the first large-scale systematic dendroclimatic sampling focused on developing chronologies from different
species in the eastern Mediterranean region. Six reconstructions were developed from chronologies ranging in length from 115 years
to 600 years. The first reconstruction (1885–2000) was derived from principal components (PCs) of 36 combined chronologies.
The remaining five, 1800–2000, 1700–2000, 1600–2000, 1500–2000 and 1400–2000 were developed from PCs of 32, 18, 14, 9, and
7 chronologies, respectively. Calibration and verification statistics for the period 1931–2000 show good levels of skill for
all reconstructions. The longest period of consecutive dry years, defined as those with less than 90% of the mean of the observed
May–August precipitation, was 5 years (1591–1595) and occurred only once during the last 600 years. The longest reconstructed
wet period was 5 years (1601–1605 and 1751–1755). No long term trends were found in May–August precipitation during the last
few centuries. Regression maps are used to identify the influence of large-scale atmospheric circulation on regional precipitation.
In general, tree-ring indices are influenced by May–August precipitation, which is driven by anomalous below (above) normal
pressure at all atmospheric levels and by convection (subsidence) and small pressure gradients at sea level. These atmospheric
conditions also control the anomaly surface air temperature distribution which indicates below (above) normal values in the
southern regions and warmer (cooler) conditions north of around 40°N. A compositing technique is used to extract information
on large-scale climate signals from extreme wet and dry summers for the second half of the twentieth century and an independent
reconstruction over the last 237 years. Similar main modes of atmospheric patterns and surface air temperature distribution
related to extreme dry and wet summers were identified both for the most recent 50 years and the last 237 years. Except for
the last few decades, running correlation analyses between the major European-scale circulation patterns and eastern Mediteranean
spring/summer precipitation over the last 237 years are non-stationary and insignificant, suggesting that local and/or sub-regional
geographic factors and processes are important influences on tree-ring variability over the last few centuries. 相似文献
16.
Herein, we calculate an aridity index, D, based on annual precipitation, P, and measured evaporation, PET, from φ20 evaporation pans: D = P/PET. The data were collected between 1951 and 1999 at 295 meteorological stations operated by the Chinese Meteorological
Administration. On the basis of the index, three climatic regions are recognized in China: an arid zone in which D ≤ 0.20, a semi-arid zone with 0.20 < D ≤ 0.50, and a humid zone in which D > 0.50. Temporal fluctuations of the climate boundaries are substantial, and differ significantly regionally, and have the
shifting features in the same direction in some areas and in opposite directions in others over the past 50 years. The semiarid
zone lies along the border of the monsoon, and is thus highly susceptible to environmental change in China. In the period
from the late 1960s to the early 1970s, the climate became drier in most parts of the regions of northern China. Moreover,
the drought has an increasing trend. The fluctuations of climatic boundaries and the alternation from drier to wetter climate
have substantial inter-decadal features. The main factors affecting the fluctuations in climate boundaries are the East Asian
summer monsoon, the Indian Monsoon, the plateau monsoon in Tibetan Plateau, the westerly circulation, and the West Pacific
Subtropical High. The different types of circulation and the strength of these circulations result in regional and temporal
differences in aridity. Inter-decadal variations of the dry- and wet climate boundary fluctuations and of the arid and humid
climate result from the inter-decadal changes of East Asian summer monsoon, Indian Monsoon, plateau monsoon, westerly circulation,
and West Pacific Subtropical High. The anomalous general atmospheric circulation in the Northern Hemisphere during the late
1960s to the early 1970s is the cause of the remarkable change in arid and humid climate in China. Major natural disasters
produced by arid and humid change are drought and flood disasters. They cause enormous economic losses to agriculture and
industry. Furthermore, the loss has a substantial increasing trend. More than 110 cities are in severe water-deficiency conditions
because of shortage of water resource in China. Drought has been a limiting factor of economic and social development in China. 相似文献
17.
M. Rebetez 《Theoretical and Applied Climatology》1996,54(3-4):99-106
Summary An analysis of correlation coefficients for climatological data covering the period 1901–1994 or 1931–1994 for six locations in Switzerland has been made in order to highlight the relationships between temperature, precipitation (rain and snow) and snow in summer and in winter. The results show that colder summers tend to be associated with more precipitation, mainly in terms of the frequency of occurrence of precipitation, but also in terms of its abundancy. In winter, sites located at lower altitudes behave differently from those at higher elevations. At lower altitudes, warmer winters tend to be rainier and to have less snow (only a small part of winter precipitation falls in the form of snow). Above 1000–1500 m, correlations between temperature on the one hand, and precipitation or snow on the other, tend to be weaker than at lower elevations; warmer winters are associated with less snow but also with less precipitation in general, while the relationship between precipitation and snow is stronger.These results confirm that during cold periods of the past, such as Löbben Phase (1400 BC — 1230 BC) cold summers were probably linked to frequent and abundant precipitation. These conditions led to increased mortality as well as to population migrations. In terms of potential future global warming, if the current temperature/precipitation relationships remain unchanged, then warmer summers will likely be linked to a decrease in precipitation. Higher winter temperatures can be expected to lead to a general decrease of snow and to a decrease in precipitation, but only at higher elevations; warmer winters would conversely be associated with an increase in precipitation at lower altitudes.With 4 Figures 相似文献
18.
Climate change,the monsoon,and rice yield in India 总被引：4，自引：1，他引：3
Recent research indicates that monsoon rainfall became less frequent but more intense in India during the latter half of the
Twentieth Century, thus increasing the risk of drought and flood damage to the country’s wet-season (kharif) rice crop. Our statistical analysis of state-level Indian data confirms that drought and extreme rainfall negatively affected
rice yield (harvest per hectare) in predominantly rainfed areas during 1966–2002, with drought having a much greater impact
than extreme rainfall. Using Monte Carlo simulation, we find that yield would have been 1.7% higher on average if monsoon
characteristics, especially drought frequency, had not changed since 1960. Yield would have received an additional boost of
nearly 4% if two other meteorological changes (warmer nights and lower rainfall at the end of the growing season) had not
occurred. In combination, these changes would have increased cumulative harvest during 1966–2002 by an amount equivalent to
about a fifth of the increase caused by improvements in farming technology. Climate change has evidently already negatively
affected India’s hundreds of millions of rice producers and consumers. 相似文献
19.
20.
南疆作为气候干旱区,夏季常发生不同类型的降水,2013年6月南疆短历时、高强度、小范围降水事件和2016年8月长时间、持续型、大范围降水事件在预报和服务方面有较大差异。分析两次强降水事件,南亚高压双体型是南疆夏季强降水的大尺度环流背景。高强度降水事件环流经向度大,高、中、低纬低槽同位相叠加,是造成强降水的直接影响系统;持续型强降水事件在500 hPa高空平均环流场上显示,欧亚范围内中高纬度地区为两脊一槽的经向环流,西西伯利亚至中亚地区的副热带大槽呈东北—西南向分布,长波槽底伸至38°N附近,是造成持续型强降水和气温持续下降或偏低的直接影响系统。本文在预报基础上,从气象服务的角度出发,结合长期、中短期、短时临近天气预报,重点分析在时间、范围和强度等方面存在明显差异的不同类型强降水过程中气象服务的递进式思路和方法,为精细化气象服务提供参考。 相似文献