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1.
Weather services base their operational definitions of “present” climate on past observations, using a 30-year normal period
such as 1961–1990 or 1971–2000. In a world with ongoing global warming, however, past data give a biased estimate of the actual
present-day climate. Here we propose to correct this bias with a “delta change” method, in which model-simulated climate changes
and observed global mean temperature changes are used to extrapolate past observations forward in time, to make them representative
of present or future climate conditions. In a hindcast test for the years 1991–2002, the method works well for temperature,
with a clear improvement in verification statistics compared to the case in which the hindcast is formed directly from the
observations for 1961–1990. However, no improvement is found for precipitation, for which the signal-to-noise ratio between
expected anthropogenic changes and interannual variability is much lower than for temperature. An application of the method
to the present (around the year 2007) climate suggests that, as a geographical average over land areas excluding Antarctica,
8–9 months per year and 8–9 years per decade can be expected to be warmer than the median for 1971–2000. Along with the overall
warming, a substantial increase in the frequency of warm extremes at the expense of cold extremes of monthly-to-annual temperature
is expected. 相似文献
2.
The increased frequency of wildfires in the United States has become a common prediction associated with the build-up of greenhouse gases. In this investigation, variations in annual wildfire data in Yellowstone National Park are compared to variations in historical climate conditions for the area. Univariate and multivariate analytical techniques reveal that (a) summer temperatures in the Park are increasing, (b) January-June precipitation levels are decreasing, and (c) variations in burn area within the Park are significantly related to the observed variations in climate. Outputs from four different general circulation model simulations for 2 × CO2 are included in the analyses; model predictions for increasing aridity in the Yellowstone Park area are generally in agreement with observed trends in the historical climate records. 相似文献
3.
哈尔滨气温的长期变化及基本态特征 总被引:1,自引:0,他引:1
利用1881—2009年的气温观测资料,研究了哈尔滨年及四季平均气温的气候基本态和气候变率特征。结果表明,20世纪80年代以来哈尔滨夏季气温变化的异常程度显著增加。在冬季,近期哈尔滨气温处于暖背景及小变率的时段,反映了哈尔滨很长时间内大多数年份还将维持暖冬天气。近49年哈尔滨平均气温、平均最高(低)气温和平均日较差的时间变化特征显示,哈尔滨的年及四季平均气温都呈上升趋势,冬季增暖幅度最大;最高(低)气温变化趋势与平均气温一致,但无论年及四季,平均最高气温的变化速率都小于平均气温,平均最低气温的变化速率都大于平均气温。 相似文献
4.
Past and future polar amplification of climate change: climate model intercomparisons and ice-core constraints 总被引:2,自引:2,他引:2
V. Masson-Delmotte M. Kageyama P. Braconnot S. Charbit G. Krinner C. Ritz E. Guilyardi J. Jouzel A. Abe-Ouchi M. Crucifix R. M. Gladstone C. D. Hewitt A. Kitoh A. N. LeGrande O. Marti U. Merkel T. Motoi R. Ohgaito B. Otto-Bliesner W. R. Peltier I. Ross P. J. Valdes G. Vettoretti S. L. Weber F. Wolk Y. YU 《Climate Dynamics》2006,26(5):513-529
Climate model simulations available from the PMIP1, PMIP2 and CMIP (IPCC-AR4) intercomparison projects for past and future
climate change simulations are examined in terms of polar temperature changes in comparison to global temperature changes
and with respect to pre-industrial reference simulations. For the mid-Holocene (MH, 6,000 years ago), the models are forced
by changes in the Earth’s orbital parameters. The MH PMIP1 atmosphere-only simulations conducted with sea surface temperatures
fixed to modern conditions show no MH consistent response for the poles, whereas the new PMIP2 coupled atmosphere–ocean climate
models systematically simulate a significant MH warming both for Greenland (but smaller than ice-core based estimates) and
Antarctica (consistent with the range of ice-core based range). In both PMIP1 and PMIP2, the MH annual mean changes in global
temperature are negligible, consistent with the MH orbital forcing. The simulated last glacial maximum (LGM, 21,000 years
ago) to pre-industrial change in global mean temperature ranges between 3 and 7°C in PMIP1 and PMIP2 model runs, similar to
the range of temperature change expected from a quadrupling of atmospheric CO2 concentrations in the CMIP simulations. Both LGM and future climate simulations are associated with a polar amplification
of climate change. The range of glacial polar amplification in Greenland is strongly dependent on the ice sheet elevation
changes prescribed to the climate models. All PMIP2 simulations systematically underestimate the reconstructed glacial–interglacial
Greenland temperature change, while some of the simulations do capture the reconstructed glacial–interglacial Antarctic temperature
change. Uncertainties in the prescribed central ice cap elevation cannot account for the temperature change underestimation
by climate models. The variety of climate model sensitivities enables the exploration of the relative changes in polar temperature
with respect to changes in global temperatures. Simulated changes of polar temperatures are strongly related to changes in
simulated global temperatures for both future and LGM climates, confirming that ice-core-based reconstructions provide quantitative
insights on global climate changes.
An erratum to this article can be found at 相似文献
5.
It has long been recognized that albedo related vegetation feedbacks amplify climate variability in North Africa. Recent studies
have revealed that areas of very high albedo associated with certain desert soil types contribute to the current dry climate
of the region. We construct three scenarios of North African albedo, one based on satellite measurements, one where the highest
albedo resembles that of soils in the desert transition zones, and one based on a vegetation map for the “green Sahara” state
of the middle Holocene, ca. 6,000 years ago. Using a series of climate model simulations, we find that the additional amplitude
of albedo change from the middle Holocene to the present caused by the very bright desert soils enhances the magnitude of
the June-to-August precipitation change in the region of the present Sahara from 0.6 to 1.0 mm/day on average. We also find
that albedo change has a larger effect on regional precipitation than changes in either the Earth’s orbit or sea surface temperatures
between 6,000 years ago and today. Simulated precipitation agrees rather well with present observations and mid Holocene reconstructions.
Our results suggest that there may exist an important climate feedback from soil formation processes that has so far not been
recognized. 相似文献
6.
This study aims to put out on what ratio Bursa province, one of the important heavy industry regions of Turkey, has been affected
climatic process called “Global Warming” or “Climate Change”. For this intend climatic measurement results from Bursa center,
top of Uludağ Mount, Yenişehir and Keles meteorological stations were used. These measurements were taken as minimum temperature
at night-time, maximum temperature at day-time, and mean temperature, mean pressure, insolation intensity, insolation duration,
mean wind speed, minimum temperature above soil, soil temperatures at depths of 5, 10, and 20 cm rainfall. Overall, our statistical
results showed that there was a considerable warming at statistically 1% and 5% levels in summer months, particularly in July
Almost all performed measurements confirm this result. According to climatic data for thirty years (1975–2005), in the last
twelve years contrary to previous 18 years, mean temperature values were higher than long-term mean value nine times (years)
repetitively. Temperatures did not deviated higher than 0.5°C in six of these. At the temperatures below mean, The maximum
deviation was −0.4°C. 相似文献
7.
Summary Annual and seasonal changes in maximum and minimum temperatures (Tmax and Tmin) and in daily temperature range (DTR) in Italy are investigated. Monthly average series for northern and southern Italy are
analysed for evidence of trend. Tmax and Tmin show a positive trend over the period 1865–1996 which is greater in southern Italy than in northern Italy. DTR shows a positive
trend, but greater in the North than in the South. There is a positive correlation between DTR and mean monthly temperature
especially in spring and in summer, while there is a high significant negative correlation between DTR and monthly precipitation.
Analysis of temperature, precipitation and DTR during the period 1865–1996 suggests that a general relationship between the
very warm last 15–20 years and an increase in the frequency of sub-tropical anticyclones over the Central-Western Mediterranean.
This relationship is based on the hypothesis that in Italy more frequent sub-tropical anticyclones could have been the most
characteristic feature of the warm periods during the last 130 years.
Received June 4, 1999 Revised November 2, 1999 相似文献
8.
Observed and projected climate change in Taiwan 总被引:1,自引:0,他引:1
Summary
This study examined the secular climate change characteristics in Taiwan over the past 100 years and the relationship with
the global climate change. Estimates for the likelihood of future climate changes in Taiwan were made based on the projection
from the IPCC climate models.
In the past 100 years, Taiwan experienced an island-wide warming trend (1.0–1.4 °C/100 years). Both the annual and daily temperature
ranges have also increased. The warming in Taiwan is closely connected to a large-scale circulation and SAT fluctuations,
such as the “cool ocean warm land” phenomenon. The water vapor pressure has increased significantly and could have resulted
in a larger temperature increase in summer. The probability for the occurrence of high temperatures has increased and the
result suggests that both the mean and variance in the SAT in Taiwan have changed significantly since the beginning of the
20th century. Although, as a whole, the precipitation in Taiwan has shown a tendency to increase in northern Taiwan and to
decrease in southern Taiwan in the past 100 years, it exhibits a more complicated spatial pattern. The changes occur mainly
in either the dry or rainy season and result in an enhanced seasonal cycle. The changes in temperature and precipitation are
consistent with the weakening of the East Asian monsoon.
Under consideration of both the warming effect from greenhouse gases and the cooling effect from aerosols, all projections
from climate models indicated a warmer climate near Taiwan in the future. The projected increase in the area-mean temperature
near Taiwan ranged from 0.9–2.7 °C relative to the 1961–1990 averaged temperature, when the CO2 concentration increased to 1.9 times the 1961–1990 level. These simulated temperature increases were statistically significant
and can be attributed to the radiative forcing associated with the increased concentration of greenhouse gases and aerosols.
The projected changes in precipitation were within the range of natural variability for all five models. There is no evidence
supporting the possibility of precipitation changes near Taiwan based on the simulations from five IPCC climate models.
Received February 5, 2001 Revised July 30, 2001 相似文献
9.
This paper describes different ways of reducing urban air temperature and their results in two cities: Campinas, Brazil—a warm temperate climate with a dry winter and hot summer (Cwa), and Mendoza, Argentina—a desert climate with cold steppe (BWk). A high-resolution microclimate modeling system—ENVI-met 3.1—was used to evaluate the thermal performance of an urban canyon in each city. A total of 18 scenarios were simulated including changes in the surface albedo, vegetation percentage, and the H/W aspect ratio of the urban canyons. These results revealed the same trend in behavior for each of the combinations of strategies evaluated in both cities. Nevertheless, these strategies produce a greater temperature reduction in the warm temperate climate (Cwa). Increasing the vegetation percentage reduces air temperatures and mean radiant temperatures in all scenarios. In addition, there is a greater decrease of urban temperature with the vegetation increase when the H/W aspect ratio is lower. Also, applying low albedo on vertical surfaces and high albedo on horizontal surfaces is successful in reducing air temperatures without raising the mean radiant temperature. The best combination of strategies—60 % of vegetation, low albedos on walls and high albedos on pavements and roofs, and 1.5 H/W—could reduce air temperatures up to 6.4 °C in Campinas and 3.5 °C in Mendoza. 相似文献
10.
Climate change,weather variability and corn yield at a higher latitude locale: Southwestern Quebec 总被引:5,自引:0,他引:5
Juan Jose Almaraz Fazli Mabood Xiaomin Zhou Edward G. Gregorich Donald L. Smith 《Climatic change》2008,88(2):187-197
Climate change has led to increased temperatures, and simulation models suggest that this should affect crop production in
important agricultural regions of the world. Nations at higher latitudes, such as Canada, will be most affected. We studied
the relationship between climate variability (temperature and precipitation) and corn yield trends over a period of 33 years
for the Monteregie region of south-western Quebec using historical yield and climate records and statistical models. Growing
season mean temperature has increased in Monterregie, mainly due to increased September temperature. Precipitation did not
show any clear trend over the 33 year period. Yield increased about 118 kg ha−1 year−1 from 1973 to 2005 (under normal weather conditions) due mainly to changes in technology (genetics and management). Two climate
variables were strongly associated with corn yield variability: July temperature and May precipitation. These two variables
explain more than a half of yield variability associated with climate. In conclusion, July temperatures below normal and May
precipitation above normal have negative effects on corn yield, and the growing seasons have warmed, largely due to increases
in the September temperature. 相似文献
11.
Feng Xue Yuan Jiang Mingchang Wang Manyu Dong Xinyuan Ding Xianji Yang Muyi Kang 《Theoretical and Applied Climatology》2020,140(1):15-24
Fully and accurately studying temperature variations in montane areas are conducive to a better understanding of climate modeling and climate-growth relationships on regional scales. To explore the spatio-temporal changes in air and soil temperatures and their relationship in montane areas, on-site monitoring over 2 years (2015 and 2016) was conducted at nine different elevations from 2040 to 2740 m a.s.l. on Luya Mountain in the semiarid region of China. The results showed that the annual mean of air temperature lapse rate (ATLR) was 0.67 °C/100 m. ATLR varied obviously in different months within a range of 0.57~0.79 °C/100 m. The annual mean of the soil temperature lapse rate (STLR) was 0.48 °C/100 m. Seasonally, monthly mean soil temperature did not show a consistent pattern with regard to elevation. The relationships between air and soil temperatures showed piecewise changes. Soil was decoupled from the air temperature in cold winter and early spring. The parameters of the growing season based on the two temperature types had no corresponding relations, and seasonal mean of soil temperature showed the smallest value at mid-elevation rather than in the treeline ecotone. Based on these changes, our results emphasized that altitudinal and seasonal variability caused by local factors (such as snow cover and soil moisture) should be taken into full consideration in microclimate extrapolation and treeline prediction in montane areas, especially in relation to soil temperature. 相似文献
12.
Ernest M. Agee 《Climatic change》1982,4(4):399-418
A diagnostic study of 80 yrs(1901–80) of surface temperatures collected at West Lafayette, Indiana, has been found to be in
tune with the global trend and that for the eastern two-thirds of the United States, namely, cold at the turn of the century,
warming up to about 1940, and then cooling to present. The study was divided into two cold periods (1901–18, 1947–80) and
a warm period (1919–46), based on the distribution of annual mean temperature. Decadal mean annual temperatures ranged from
10 °C in period I to 12.2 °C in period II, to 9.4 °C during the present cold period. Themean annual temperature for the 80 yr ranged from the coldest of 8.7 °C in 1979 to the warmest of 13.6 °C in 1939. Thedaily mean temperature for the entire 80-yr ranged from -4.7 °C on 31 January to 25.1 °C on 27 July. Thecoldest daily mean was -26.7 °C on 17 January, 1977, and thewarmest daily mean was 35 °C on 14 July, 1936. The range of values for thedaily mean maximum temperatures was -.2 °C on 31 January to 31.4 °C on 27 July. Corresponding values for thedaily mean minimum are -9.2 °C on 31 January and 18.7 °C on 27 July. The all-time extreme temperatures are -30.6 °C on 26 February, 1963 and
43.9 °C on 14 July, 1936.
Climatic variability has been considered by computing the standard deviations of a) the daily mean maximum and minimum temperature
per year, and b) the daily mean maximum and minimum temperatures for each day of the year for the 80-yr period. These results
have shown that there is more variability in the daily mean maximum per year than in the daily mean minimum, for each year
of the 80-yr period. Also the variability for both extremes has been greater in each of the two cold periods than in the warm
period. Particularly noticeable has been theincrease in the variability of the daily mean minima per year during the current cooling trend. Further, it has been determined that
the variability in the daily mean maxima and minima for each day of the year (based on the entire 80 yrs is a) two times greater
in the winter than in the summer for both extremes, and b) about the same for each in the summer, greater for daily maximum
in the spring and fall, but greater for the daily minimum during the winter. The latter result is undoubtedly related to the
effect of snow cover on daily minimum temperatures.
An examination of daily record maximum and minimum temperatures has been made to help establish climatic trends this century.
For the warm period, 175 record maxima and 68 record minima were set, compared to 213 record minima and 105 record maxima
during the recent cold period. For West Lafayette, the present climatic trend is definitely one of extreme record-breaking
cold. Evidence has also been presented to show the substantial increases in snowfall amounts in the lee regions of the Great
Lakes during the present cold period, due to the lake-induced snow squalls associated with cold air mass intrusions. The possible
impact of the cooling trend on agricultural activities has also been noted, due to a reduced growing season. 相似文献
13.
应用均一化逐日气象观测资料,分析了北京地区1960—2008年气候变暖及主要极端气温指数的统计特征。结果表明:近49年来北京年平均气温增温速率约为0.39℃/10a,最高、最低气温变化具有明显的非对称性。霜冻日数和气温年较差呈现下降趋势,暖夜指数及热浪指数呈现上升趋势,除气温年较差外,其他极端气温指数的气候变率均在加大。北京年平均气温及极端气温指数主要存在21年、15~17年及准10年周期特征。年平均气温与极端气温指数之间存在较强相关性,气候变暖突变发生前后某些极端气温指数发生频率表现出明显差异。自1980年起,北京市区极端最高气温及其增温率明显高于近郊和远郊,高温日数市区多于近郊,近郊多于远郊;近、远郊极端最低气温温差高于城、近郊温差。 相似文献
14.
August 2006 was an exceptionally wet month in the Netherlands, in particular near the coast where rainfall amounts exceeded
300% of the climatological mean. August 2006 was preceded by an extremely warm July with a monthly mean temperature of almost
1°C higher than recorded in any other summer month in the period 1901–2006. This had resulted in very high sea surface temperatures
(SSTs) in the North Sea at the end of July. In this paper the contribution of high SSTs to the high rainfall amounts is investigated.
In the first part of this study, this is done by analyzing short-term integrations with a regional climate model (RACMO2)
operated at 6 km resolution, which are different in the prescribed values of the SSTs. In the second part of the paper the
influence of SSTs on rainfall is analyzed statistically on the basis of daily observations in the Netherlands during the period
1958–2006. The results from both the statistical analysis as well as the model integrations show a significant influence of
SSTs on precipitation. This influence is particularly strong in the coastal area, that is, less than 30–50 km from the coastline.
With favorable atmospheric flow conditions, the analyzed dependency is about +15% increase per degree temperature rise, thereby
exceeding the Clausius–Clapeyron relation—which is often used as a temperature related constraint on changes in extreme precipitation—by
approximately a factor of two. It is shown that the coastal area has consistently become wetter compared to the inland area
since the 1950s. This finding is in agreement with the rather strong observed trend in SST over the same period and the dependencies
of rainfall on SST reported in this study. 相似文献
15.
Recent and future sea surface temperature trends in tropical pacific warm pool and cold tongue regions 总被引:3,自引:2,他引:1
Soon-Il An Ji-Won Kim Seul-Hee Im Beak-Min Kim Jae-Heung Park 《Climate Dynamics》2012,39(6):1373-1383
Using coral data, sea surface temperature (SST) reanalysis data, and Climate Model Intercomparison Project III (CMIP3) data, we analyze 20th-century and future warm pool and cold tongue SST trends. For the last 100?years, a broad La Nina-like SST trend, in which the warming trend of the warm pool SST is greater than that of the cold tongue SST, has appeared in reanalysis SST data sets, 20C scenario experiments of the CMIP3 data and less significantly in coral records. However, most Coupled General Circulation Models subjected to scenarios of future high greenhouse gas concentrations produce larger SST warming trends in cold tongues than in warm pools, resembling El Nino-like SST patterns. In other words, warmer tropical climate conditions correspond to stronger El Nino-like response. Heat budget analyses further verify that warmer tropical climates diminish the role of the ocean’s dynamic thermostat, which currently regulates cold tongue temperatures. Therefore, the thermodynamic thermostat, whose efficiency depends on the mean temperature, becomes the main regulator (particularly via evaporative cooling) of both warm pool and cold tongue temperatures in future warm climate conditions. Thus, the warming tendency of the cold tongue SST may lead that of the warm pool SST in near future. 相似文献
16.
17.
The regional patterns of change of temperature and rainfall that might accompany a global warming due to increased carbon
dioxide can be studied by experiments with theoretical models of the climate system, by reconstructing the climates of past
warm epochs, and by determining the anomalies of temperature and precipitation that prevailed during years or seasons when
the Arctic region was unusually warm. The current study pursues the last course, making use of the northern hemisphere meteorological
data record for the period 1931–1978. Hemispheric maps of anomalies of both temperature and precipitation are presented for
the 10 warmest Arctic seasons and years, and for differences between the 5 warmest and 5 coldest consecutive Arctic winters.
Wintertime anomalies are generally greatest and dominate in determining the annual averages. The hemispheric temperature anomalies
for these data sets are similar to those determined earlier by the first author (Williams, 1980) using 1900–1969 data, but
the precipitation anomalies (for North America alone) show more variation, partly due to the method of computing the anomalies.
Work reported here begun while a visitor to the National Center for Atmospheric Research.
The National Center for Atmospheric Research is sponsored by the National Science Foundation. 相似文献
18.
中国柯本气候分类 总被引:2,自引:0,他引:2
利用中国734个气象站点1957-2016年的气温和降水量数据,结合柯本气候分类,采用薄板样条插值法,研究中国柯本气候分类的时空分布及变化特征。结果表明:1957-2016年中国包括5个气候带,其中赤道气候带(0.17%)包括热带季风和热带疏林草原气候,干旱气候带(41.38%)包括冷性沙漠和冷性草原气候,暖温气候带(25.53%)包括热夏冬干暖温、温夏冬干暖温、热夏常湿暖温以及温夏常湿暖温气候类型,冷温气候带(28.44%)包括热夏冬干冷温、温夏冬干冷温、冷夏冬干冷温、热夏常湿冷温、温夏常湿冷温以及冷夏常湿冷温气候类型,极地气候带(4.48%)仅有苔原气候。在此60 a,气候变化主要体现在冷温气候带向干燥气候带和暖温气候带的转移,以及冷温气候带中冷夏向温夏的转移和温夏向热夏的转移。 相似文献
19.
Summary Climatic changes of summer temperature and precipitation in the greater Alpine region are assessed by using statistical-dynamical
downscaling. The downscaling procedure is applied to two 30-year periods (1971–2000 and 2071–2100, summer months only) taken
from the results of a transient coupled ocean/atmosphere climate scenario simulation with increasing greenhouse gas concentrations.
The downscaling results for the present-day climate are compared with observations. The estimated regional climate change
during the next 100 years shows a general warming. The mean summer temperatures increase by 3 to 5 Kelvin. The most intense
climatic warming is predicted in the western parts of the Alps. The amount of summer precipitation decreases in most parts
of central Europe by more than 20 percent. Increasing precipitation is simulated only over the Adriatic area and parts of
eastern central Europe.
The results are compared with observed climate trends for the last decades and results of other regional climate change estimations.
The observed trends and the majority of the simulated trends (including ours) have a number of common features. However, there
are also climate change estimates of other groups which completely contradict our results.
Received April 8, 1999 Revised November 16, 1999 相似文献
20.
The present study analyzes the differences in spatial and temporal variations of
surface temperatures between early and late onset years of the South China Sea summer monsoon
(SCSSM). It is found that when the land surface temperature north of 40oN is lower (higher)
and the sea surface temperature over the South China Sea-western North Pacific (SCS-WNP) is
higher (lower) in winter, the onset of the SCSSM begins earlier (later). When the land surface
temperature north of 40oN is higher (lower) and the sea surface temperature over the SCS-WNP
is lower (higher) in spring, the onset of the SCSSM occurs earlier (later). The reason why the
anomalies of the land surface temperatures north of 40oN can influence the atmospheric circulation
is investigated by analysis of the wind and temperature fields. In order to verify the mechanisms
of influence over the land and sea surface temperature distribution patterns and test the ability
of the p-σ regional climate model (p-σ RCM9) to simulate the SCSSM onset, three types
of years with early, normal, and late SCSSM onset are selected and the SCSSM regimes are numerically
simulated. According to the results obtained from five sensitive experiments, when the land surface
temperature is higher in the eastern part, north of 40oN, and lower in the western part, north
of 40oN, and it rises faster in the eastern coastal regions and the Indian Peninsula, while the
sea surface temperatures over the SCS-WNP are lower, the early onset of the SCSSM can be expected. 相似文献