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1.
Jill Williams 《Climatic change》1980,2(3):249-266
Recently much concern has been expressed regarding the impact of an increased atmospheric CO2 concentration on climate. Unfortunately, present understanding and models of the climate system are not good enough for reliable prediction of such impacts. This paper presents an analysis of recent climate data in order to illustrate the nature of regional temperature and rainfall changes in different seasons and to provide some guidance with regard to points which might be borne in mind when scenarios of future climate (especially those taking into account human impacts) are being formulated.Since it is believed that an increased atmospheric CO2 concentration will cause a warming and models and data suggest that the Arctic is more sensitive to climatic change than other latitudes, anomalies associated with warm Arctic seasons have been studied.The regional temperature, precipitation and pressure anomalies in the northern hemisphere for the 10 warmest Arctic winters and 10 warmest Arctic summers during the last 70 years have been investigated. Even when the Arctic area is warm, there are circulation changes such that large coherent anomalies occur elsewhere, with some regions warming and some cooling. The 10 warmest Arctic winters were characterised by larger amplitude anomalies, in the Arctic and elsewhere, than the 10 warmest summers, illustrating the difference in response between seasons. The precipitation differences for the 10 warmest Arctic winters and summers show for North America large coherent areas of increase or decrease, which again differ according to season. However, in winter the differences are not statistically significant, while the differences in two areas are significant in summer. 相似文献
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通过对我国北方地区影响日光温室生产的主要气候因素进行分析,从光、温、风、雪4个方面选取了冬季总辐射、日光温室生产季阴天日数、年极端最低气温、冬季平均气温、生产季月最大风速平均值、年最大积雪深度平均值6个因子作为气候适宜性区划指标,采用加权指数求和的评价方法建立综合气候适宜性区划指标模型,在利用层次分析法对区划指标进行量化分析确定其权重的基础上,借助GIS技术,得到北方地区日光温室发展的气候适宜性区划图。为了细化区划结果,将研究区域气候特征明显不同的典型区域分别进行进一步区划。结果表明:该方法不仅理论性较强,与实际相吻合的区划结果也说明该方法还具有良好的实用性。 相似文献
4.
以陕南商洛地区为例, 选取适当的农业气候区划及垂直分层指标, 利用GIS空间分析及制图功能, 在实现指标空间化基础上, 采用模糊综合评判方法, 实现山区农业气候垂直分层。结果表明:商洛地区在不同气候带内可分别划分3个垂直气候层:北亚热带山区有温热易旱层 (低于700 m)、温暖半湿润层 (750~1250 m) 和温凉冷凉湿润层 (1250~1800 m); 暖温带山区包括温暖易旱层 (800~1100 m)、温凉半湿润层 (1100~1500 m) 和冷凉湿润层 (1500~2500 m)。并对各层适宜发展农业生态类型进行了评述。 相似文献
5.
Cary J. Mock 《Climatic change》2000,44(1-2):173-195
The recent accumulation of all published precipitation records from 1870–1889 in the central and northern Great Plains of the United States provides a renewed potential in analyzing climatic reality during early settlement, corresponding to a time when some written histories documented that the Rain followed the Plow. Growing season precipitation in the central and northern Great Plains from 1870–1889 were examined relative to modern climatic normals (1961–1990). Growing season totals mostly exhibit little changes in precipitation in the region as compared to today. Some wetter springs and summers occurred in the Dakotas during the late 1870s and early 1880s, subsequent to the drier early-mid 1870s and corresponding to the Great Dakota Boom. Wetter summers occurred over the central Plains in the mid-1880s, corresponding to increased migration in Nebraska and Kansas. Drier summers occurred during the early 1870s and inactive settlement in the early 1880s. Although increased rainfall may have been conducive for early settlement, in general the Rain did not follow the Plow, with extreme seasonal and monthly heavy precipitation events at the subregional scale perhaps playing important roles on settlers' climatic perceptions. The results of this study provide a framework in order to conduct historical climate impact analyses as well as information that can be applied towards understanding spatial climatic variations further back into time. 相似文献
6.
Some mechanisms of mid-Holocene climate change in Europe,inferred from comparing PMIP models to data
We propose a new approach for comparing mid-Holocene climates from 18 PMIP simulations with climate reconstructions of winter and growing season temperatures and the annual water budget inferred from European pollen and lake-level data. A cluster analysis is used to extract patterns of multivariate climate response from the reconstructions; these are then compared to the patterns simulated by models. According to paleodata, summers during mid-Holocene were warmer-than-present in the north, and cooler-than-present in the south, while winters were colder-than-present in the southwest but milder-than-present in the northeast. Whereas warmer summers and colder winters may easily be explained as a direct response to the amplified seasonal cycle of insolation during the mid-Holocene, the other recorded responses are less straightforward to explain. We have identified, from the models that correctly simulate the recorded climate change, two important atmospheric and hydrological processes that can compensate for direct insolation effects. First, a stronger-than-present airflow from southwestern Europe that veers to the north over Eastern Europe, in winter, can consistently explain the reconstructed changes in this seasons temperatures and water budget. Second, the increased winter soil moisture allows a shift of the partitioning of net radiative energy towards latent rather than sensible heat fluxes, thereby decreasing surface temperature during the following summer season. Our approach therefore solves one of the recurring problems in model-data comparisons that arises when a model simulates the correct response but in the wrong location (as a consequence, for instance, of model resolution and topography). 相似文献
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8.
Snow pack in the Swiss Alps under changing climatic conditions: an empirical approach for climate impacts studies 总被引：1，自引：0，他引：1
Summary ?In many instances, snow cover and duration are a major controlling factor on a range of environmental systems in mountain
regions. When assessing the impacts of climatic change on mountain ecosystems and river basins whose origin lie in the Alps,
one of the key controls on such systems will reside in changes in snow amount and duration. At present, regional climate models
or statistical downscaling techniques, which are the principal methods applied to the derivation of climatic variables in
a future, changing climate, do not provide adequate information at the scales required for investigations in which snow is
playing a major role. A study has thus been undertaken on the behavior of snow in the Swiss Alps, in particular the duration
of the seasonal snow-pack, on the basis of observational data from a number of Swiss climatological stations. It is seen that
there is a distinct link between snow-cover duration and height (i.e., temperature), and that this link has a specific “signature”
according to the type of winter. Milder winters are associated with higher precipitation levels than colder winters, but with
more solid precipitation at elevations exceeding 1,700–2,000 m above sea-level, and more liquid precipitation below. These
results can be combined within a single diagram, linking winter minimum temperature, winter precipitation, and snow-cover
duration. The resulting contour surfaces can then be used to assess the manner in which the length of the snow-season may
change according to specified shifts in temperature and precipitation. While the technique is clearly empirical, it can be
combined with regional climate model information to provide a useful estimate of the length of the snow season with snow cover,
for various climate-impacts studies.
Received May 14, 2002; revised August 12, 2002; accepted August 17, 2002 相似文献
9.
Yura Kim Mikyoung Jun Seung-Ki Min Myoung-Seok Suh Hyun-Suk Kang 《Asia-Pacific Journal of Atmospheric Sciences》2016,52(2):237-249
CORDEX-East Asia, a branch of the coordinated regional climate downscaling experiment (CORDEX) initiative, provides high-resolution climate simulations for the domain covering East Asia. This study analyzes temperature data from regional climate models (RCMs) participating in the CORDEX - East Asia region, accounting for the spatial dependence structure of the data. In particular, we assess similarities and dissimilarities of the outputs from two RCMs, HadGEM3-RA and RegCM4, over the region and over time. A Bayesian functional analysis of variance (ANOVA) approach is used to simultaneously model the temperature patterns from the two RCMs for the current and future climate. We exploit nonstationary spatial models to handle the spatial dependence structure of the temperature variable, which depends heavily on latitude and altitude. For a seasonal comparison, we examine changes in the winter temperature in addition to the summer temperature data. We find that the temperature increase projected by RegCM4 tends to be smaller than the projection of HadGEM3-RA for summers, and that the future warming projected by HadGEM3-RA tends to be weaker for winters. Also, the results show that there will be a warming of 1-3°C over the region in 45 years. More specifically, the warming pattern clearly depends on the latitude, with greater temperature increases in higher latitude areas, which implies that warming may be more severe in the northern part of the domain. 相似文献
10.
Plants and animals are responding to climate warming with predictable changes in distribution and physiology. Ectothermic animals are dependent upon environmental temperature, and their seasonal activity patterns are constrained by temperature. Ectotherms (such as snakes) may alter their activity patterns in concordance with climatic change, and we tested this hypothesis in a Mediterranean region (SE Spain) with the Montpellier snake (Malpolon monspessulanus). Temperature showed an increasing trend of 0.07°C per year in the study area between 1983 and 2004, and activity period in this species increased in concert with annual mean temperature. These snakes had a wider dispersion in activity dates and the annual last record was delayed as years progressed, suggesting that the activity period for this snake has increased over time in response to climatic change. These results were not influenced by the elevation at which samples were taken, and annual variation in the number of snakes recorded, sex-ratio, or precipitation. Therefore, this study reports a definite phenological shift for a reptile in response to climatic change. 相似文献
11.
Summary A series of anomalously cold and warm winters which occurred in Switzerland during the 15-year period from 1979 to 1993 has been analyzed in detail in terms of temperature minima. The warm winters between 1988–1992 were particularly marked in the Alps, where lack of snow had severe consequences for the tourist-based economies of mountain communities. The investigations presented here focus primarily on minimum temperature records for up to 88 climatological observing sites distributed over Switzerland.Analyses of the departures of temperature minima from the 15-year means in warm and cold winters has shown that there is a very significant altitudinal dependency of the anomalies except at low elevations which are subject to fog or stratus conditions; the stratus tends to decouple the underlying stations from processes occurring at higher altitudes. It is also shown that there is a switch in the gradient of the temperature anomaly with height from cold to warm winters. For warm winters, the higher the elevation, the stronger the positive anomaly; the reverse is true for cold winters. The statistics for the 88 observational stations provide a measure of the damping of the climate signal as an inverse function of height. The altitudinal dependency of temperature departures from the mean are the most important feature, followed by latitudinal effects (north and south of the Alps); continentality is not seen to be a major factor in determining the geographical distribution of temperature anomalies at this scale.The present investigation also emphasizes the fact that high elevation records can more readily identify significant interannual climatic fluctuations than at lower-elevation sites. This is also likely to be the case for longer-term climate change, where possibe greenhouse-gas warming would presumably be detected with more clarity at higher elevations. This type of study can help orientate future high-resolution climate model studies of climate change and in particular the assessment of model capability in reproducing a range of possible temperature anomalies and their altitudinal dependency.With 12 Figures 相似文献
12.
Guiming Wang N. Thompson Hobbs Francis J. Singer Dennis S. Ojima Bruce C. Lubow 《Climatic change》2002,54(1-2):205-223
Changing climate may impact wildlife populations in national parks and conservation areas. We used logistic and non-linear matrix population models and 35 years of historic weather and population data to investigate the effects of climate on the population dynamics of elk in Rocky Mountain National Park (RMNP), Colorado, U.S.A. We then used climate scenarios derived from Hadley and Canadian Climate Center (CCC) global climate models to project the potential impact of future climate on the elk population. All models revealed density-dependent effects of population size on growth rates. The best approximating logistic population model suggested that high levels of summer precipitation accelerated elk population growth, but higher summer minimum temperatures slowed growth. The best approximating non-linear matrix model indicated that high mean winter minimum temperatures enhanced recruitment of juveniles, while high summer precipitation enhanced the survival of calves. Warmer winters and wetter summers predicted by the Hadley Model could increase the equilibrium population size of elk by about 100%. Warmer winters and drier summers predicted by the CCC Model couldraise the equilibrium population size of elk by about 50%. Managers of national parks have relied on effects of weather, particularly severe winters, to regulate populations of native ungulates and prevent harmful effects of overabundance. Our results suggest that these regulating effects of severe winter weather may weaken if climate changes occur as those that are widely predicted in most climate change scenarios. 相似文献
13.
Lorenzo Marini Matthew P. Ayres Andrea Battisti Massimo Faccoli 《Climatic change》2012,115(2):327-341
Temperature warming and the increased frequency of climatic anomalies are expected to trigger bark beetle outbreaks with potential severe consequences on forest ecosystems. We characterized the combined effects of climatic factors and density-dependent feedbacks on forest damage caused by Ips typographus (L.), one of the most destructive pests of European spruce forests, and tested whether climate modified the interannual variation in the altitudinal outbreak range of the species. We analyzed a 16-year time-series from the European Alps of timber loss in Picea abies Karsten forests due to I. typographus attacks and used a discrete population model and an information theoretic approach to compare multiple competing hypotheses. The occurrence of dry summers combined with warm temperatures appeared as the main abiotic triggers of severity of outbreaks. We also found an endogenous negative feedback with a 2-year lag suggesting a potential important role of natural enemies. Forest damage per hectare averaged 7-fold higher where spruce was planted in sites warmer than those within its historical climatic range. Dry summers, but not temperature, was related to upward shifts in the altitudinal outbreak range. Considering the potential increased susceptibility of spruce forests to insect outbreaks due to climate change, there is growing value in mitigating these effects through sustainable forest management, which includes avoiding the promotion of spruce outside its historical climatic range. 相似文献
14.
Summary Climatic patterns associated with extreme modes of summer rainfall over southern Africa are investigated using composite techniques. Differences between the wet summers of the mid-1970s and the dry summers of the early 1980s are highlighted. In dry summers both the Southern Oscillation Index (SOI) and Quasi-Biennial Oscillation (QBO) are negatively biased. Composite difference fields of outgoing longwave radiation (OLR), sea surface temperature (SST), and upper and lower tropospheric wind are analysed. The OLR difference field indicates the widespread nature of convective variations with a consistent sign in the domain 15–33° S, 0–40° E. An area of opposing sign is conspicuous over the southwest Indian Ocean and represents a dipole, whereby wet summers over southern Africa coincide with dry summers over the adjacent ocean. This dipole behaviour is an expression of the primary mode of interannual climatic variability in the region. SST composite differences are negative over a wide portion of the central equatorial Indian Ocean and SE Atlantic, and positive to the south of Africa where the Agulhas Current flows. Wind composites reveal distinctive circulation differences in the extreme summers considered. In the tropical zone off the east coast of Africa difference vectors indicate upper westerly and lower easterly circulation anomalies, and distinguish a pathway for moist Indian Ocean air. A deep anticyclonic gyre is located over the region of positive SST differences in the sub-tropics to the SE of Africa. The identification of climatic patterns in extreme summers offers some useful guidelines in seasonal forecasts.With 6 Figures 相似文献
15.
采用1951～2007年南疆地区站点月平均气温资料和NCAR/NCEP气候月平均资料,运用二项式系数加权平均法、Morlet小波变换等方法分析了南疆地区冬季和夏季气温的季节—年际气候变化特征,及气温异常的时空变化特征.结论如下:南疆地区冬季和夏季气温在气候态上差异明显,1980年代以前的冬季主要为气温负异常,1980年代以后呈现气温异常升高,到2000年以后又开始出现偏冷趋势;夏季气温偏差小于冬季,57 a间南疆夏季气温大致出现两波振荡,异常偏热期大致处于1950年代、1970年代后期和21世纪初,呈20～25 a振荡.冷冬年的频次多于暖冬年,热夏年的频次多于凉夏年.偏冷年在57a时间段内所占比例最多,气温异常低的幅度大于气温异常高的幅度.南疆冬季气温存在2个显著振荡:6～10 a的年际周期和18～20 a的年代际周期;夏季气温有1个最显著的振荡,稳定的20 a为中心的周期.不同的年代和季节气温及气温偏差分布各不相同.从气温长期演变趋势来看不论冬夏南疆北部(天山山脉以南)气温升高,塔里木盆地以及南疆南部地区气温降低.冬季升温区的升温幅度比夏季升温区大,夏季降温区的降温幅度比冬季降温区大. 相似文献
16.
Philip W. Mote Edward A. Parson Alan F. Hamlet William S. Keeton Dennis Lettenmaier Nathan Mantua Edward L. Miles David W. Peterson David L. Peterson Richard Slaughter Amy K. Snover 《Climatic change》2003,61(1-2):45-88
The impacts of year-to-year and decade-to-decade climatic variations on some of the Pacific Northwest's key natural resources can be quantified to estimate sensitivity to regional climatic changes expected as part of anthropogenic global climatic change. Warmer, drier years, often associated with El Niño events and/or the warm phase of the Pacific Decadal Oscillation, tend to be associated with below-average snowpack, streamflow, and flood risk, below-average salmon survival, below-average forest growth, and above-average risk of forest fire. During the 20th century, the region experienced a warming of 0.8 °C. Using output from eight climate models, we project a further warming of 0.5–2.5 °C (central estimate 1.5 °C) by the 2020s, 1.5–3.2°C (2.3 °C) by the 2040s, and an increase in precipitation except in summer. The foremost impact of a warming climate will be the reduction of regional snowpack, which presently supplies water for ecosystems and human uses during the dry summers. Our understanding of past climate also illustrates the responses of human management systems to climatic stresses, and suggests that a warming of the rate projected would pose significant challenges to the management of natural resources. Resource managers and planners currently have few plans for adapting to or mitigating the ecological and economic effects of climatic change. 相似文献
17.
Feng Chen Yu-jiang Yuan Wen-shou Wei Shu-long Yu Tong-wen Zhang 《Theoretical and Applied Climatology》2012,109(1-2):141-151
Until recently, there have been very few tree-ring studies in southeast China due largely to the scarcity of old trees and the complexity of relationships between tree growth and climate in subtropical regions of China. Recent studies on the conifers in southeast China revealed that tree ring-based climate reconstructions are feasible. Here, we describe a reconstruction (AD 1850–2009) of November–February maximum temperatures for Changting, Fujian, southeast China based on tree ring width data of Pinus massiniana which considerably extends the available climatic information. Calibration and verification statistics for the period 1956–2009 show a high level of skill and account for a significant portion of the observed variance (32.9%) irrespective of which period is used to develop or verify the regression model. Split sample validation supports our use of a reconstruction model based on the full period of reliable observational data (1956–2009). Warm periods occurred during 1854–1859, 1868–1880, 1885–1899, 1906–1914, 1920–1943, 1964–1975 and 1994–present; while the periods of AD 1850–1853, 1860–1867, 1881–1884, 1900–1907, 1915–1919, 1944–1963 and 1976–1993 were relatively cold. The climate correlation analyses with gridded temperature dataset and SST revealed that our season temperature reconstruction contains the strong large-scale climate signals. Our results suggest that some warm winters of Changting are coincident with El Ni?o events over the past 150?years. In addition, several severely cold winters coincide with major volcanic eruptions. 相似文献
18.
In the last decade, much effort was dedicated to the reconstruction of past climate at high temporal resolution. Here, we show the suitability of chrysophyte cysts from lake sediments for revealing continental climate variability when used in sensitive sites, such as those in high mountains. We demonstrate that altitude is a main factor influencing the present distribution of chrysophytes and develop a transfer function to evaluate the local altitude anomaly on a lake site throughout time. Based on our knowledge of chrysophyte ecology, the altitude anomalies are interpreted as winter/spring climate signatures. The method was applied to a Holocene record from a lake in the Pyrenees showing submillennial climatic variability in this northwestern Mediterranean zone. A warming trend was present from the early Holocene to 4 kyear BP. Comparison with pollen-based reconstructions of summer temperatures denoted a contrasting decrease in continentality between the two parts of the Holocene. Oscillations of 1 cycle per ca. 2,000 years appeared throughout the record. The warmest Holocene winters were recorded during the Medieval Warm Period at ca. AD 900 and 450 and the Roman Warm Period (2.7–2.4 kyear BP). Winters in the period AD 1,050–1,175 were inferred to be as cold as in the Little Ice Age. The period between 3 and 7 kyear BP showed lower intensity in the fluctuations than in early and late Holocene. The cold event, 8,200 years ago, appeared embedded in a warm fluctuation. Another cold fluctuation was recorded around 9 kyear BP, which is in agreement with Irish and Greenland records.This revised version was published online in January 2005 with corrections to the background of figures 9 and 12. 相似文献
19.
该文回顾了过去几十年来中国气象科学研究院在气候和气候变化研究方面的成果, 主要包括对我国历史气候资料的恢复、重建和整理, 气候区划, 对我国气温和降水的研究, 对青藏高原温度和降水、近地层与边界层地-气过程, 大气热源特征和臭氧变化的研究, 古气候模拟, 对气候变化的预测理论和方法以及气候和气候变化对我国社会、经济的影响等方面的研究。近50年中国气象科学研究院收集大量气候资料并整理出版了《中国近五百年旱涝分布图集》; 对风能等资源进行了气候区划; 明确了近几十年中国地区在20世纪40年代和90年代出现了两个暖期, 20世纪50—60年代出现了相对冷期; 在全球变暖的背景下, 以四川为中心的西南地区自20世纪50年代到80年代一直在变冷; 20世纪80年代以后, 多雨带由华北南移到长江中下游地区; 提出青藏高原近地层与边界层地-气过程的综合物理图像; 发现青藏高原夏季臭氧低值中心; 模拟出青藏高原隆起过程中中国气候变化特征; 揭示出东亚季风环流系统及其成员; 设计了多种预报方法; 还将气候和气候变化研究成果向国家经济转化。 相似文献
20.
B. G. Hunt 《Climate Dynamics》2011,37(7-8):1501-1515
Output from a multi-millennial simulation with the CSIRO Mark 2 coupled global climatic model has been analysed to determine the principal characteristics of extreme winters over the globe for ??present conditions??. Thus, this study is not concerned with possible changes in winter conditions associated with anthropogenically induced climatic change. Defining an extreme winter as having a surface temperature anomaly of below ?2 standard deviations (sd) revealed a general occurrence rate over the globe of between 100 and 200 over a 6,000-year period of the simulation, with somewhat higher values over northwest North America. For temperature anomalies below ?3?sd the corresponding occurrence rate drops to about 10. Spatial correlation studies revealed that extreme winters over regions in Europe, North America or Asia were very limited geographically, with time series of the surface temperature anomalies for these regions having mutual correlation coefficients of about 0.2. The temporal occurrence rates of winters (summers) having sd below ?3 (above +3) were very asymmetric and sporadic, suggesting that such events arise from stochastic influences. Multi-year sequences of extreme winters were comparatively rare events. Detailed analysis revealed that the temporal and spatial evolution of the monthly surface temperature anomalies associated with an individual extreme winter were well replicated in the simulation, as were daily time series of such anomalies. Apart from an influence of the North Atlantic Oscillation on extreme winters in Europe, other prominent climatic oscillations were very poorly correlated with such winters. Rather modest winter temperature anomalies were found in the southern hemisphere. 相似文献