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1.
土壤湿度年际变化对中国区域极端气候事件模拟的影响研究Ⅱ.敏感性试验分析 总被引：2，自引：1，他引：1
利用NCARCAM3.1大气环流模式,设计了有、无土壤湿度年际异常的两组数值试验,探讨了土壤湿度年际异常对极端气候事件模拟的可能影响。结果表明,模式模拟的极端气候事件对土壤湿度异常十分敏感,土壤湿度异常对极端气候指标的多年平均空间分布、年际变率以及年际变化均具有重要影响。当不考虑土壤湿度的年际异常时:(1)模拟的暖夜日数、暖昼日数和热浪持续指数的发生频次在全国范围内均明显减少,而霜冻日数则明显增加。极端降水指标的响应表现出明显的空间差异,极端降水频次在江淮流域明显减小,而极端降水强度则表现为东北减弱、长江流域增强;中雨日数和持续湿期在我国大部分地区减少。(2)极端气温指标的年际变率在我国大部分地区呈减小趋势;而极端降水事件的变化则较为复杂,极端降水频次和极端降水强度的年际变率在长江以南有所增强,而北方地区则有所减弱。中雨日数和持续湿期的年际变率在我国呈现出较为一致的减少趋势。(3)模式对暖夜日数、霜冻日数的年际变化的模拟能力明显下降,并对4个极端降水指标的年际变化的模拟能力在全国多数区域均有不同程度的下降。 相似文献
2.
Based on climate extreme indices calculated from a high-resolution daily observational dataset in China during1961–2005, the performance of 12 climate models from phase 6 of the Coupled Model Intercomparison Project(CMIP6),and 30 models from phase 5 of CMIP(CMIP5), are assessed in terms of spatial distribution and interannual variability. The CMIP6 multi-model ensemble mean(CMIP6-MME) can simulate well the spatial pattern of annual mean temperature,maximum daily maximum temperature, and minimum daily minimum temperature. However, CMIP6-MME has difficulties in reproducing cold nights and warm days, and has large cold biases over the Tibetan Plateau. Its performance in simulating extreme precipitation indices is generally lower than in simulating temperature indices. Compared to CMIP5, CMIP6 models show improvements in the simulation of climate indices over China. This is particularly true for precipitation indices for both the climatological pattern and the interannual variation, except for the consecutive dry days. The arealmean bias for total precipitation has been reduced from 127%(CMIP5-MME) to 79%(CMIP6-MME). The most striking feature is that the dry biases in southern China, very persistent and general in CMIP5-MME, are largely reduced in CMIP6-MME. Stronger ascent together with more abundant moisture can explain this reduction in dry biases. Wet biases for total precipitation, heavy precipitation, and precipitation intensity in the eastern Tibetan Plateau are still present in CMIP6-MME, but smaller, compared to CMIP5-MME. 相似文献
3.
土壤湿度年际变化对中国区域极端气候事件模拟的影响研究 I. 基于CAM3.1的模式评估 总被引：6，自引：2，他引：4
利用NCAR大气模式CAM3.1对中国区域近40年的极端气候事件进行了模拟试验;在此基础上, 利用1961～2000年中国区域452站的逐日最高、最低气温和降水资料, 从气候平均、年际变化和长期变化趋势等方面全面评估了该模式对中国极端气候事件的模拟能力。结果表明:(1)模式对中国区域极端气候指数气候平均态的大尺度空间分布特征具有一定的模拟能力;模式对极端降水指标空间分布的模拟能力较好, 而对极端气温指标的模拟较差;模式对极端气候指标的模拟存在系统性的偏差, 模拟的极端降水的系统性偏差要远大于对极端温度的模拟。(2)模式对极端气温指数的年际变化特征具有较强的模拟能力, 而对极端降水指数的年际变化基本没有模拟能力;模式模拟的各极端降水指标的年际变幅与观测存在较大的偏差。(3)模式较好地模拟出了暖夜和暖昼指数在中国大部分区域的增加趋势, 但变幅较实测偏小;模式对热浪持续指数长期趋势的模拟则相对略差。模式对极端气温指标长期趋势的模拟能力总体优于对极端降水指标的模拟。模式对极端降水频次和中雨日数长期趋势的模拟尚可, 但对持续湿期长期趋势的空间分布模拟较差。研究结果可为该模式用于极端气候的模拟研究提供一定参考。 相似文献
4.
Zhihong Jiang Jie Song Laurent Li Weilin Chen Zhifu Wang Ji Wang 《Climatic change》2012,110(1-2):385-401
Observations from 550 surface stations in China during 1961–2000 are used to evaluate the skill of seven global coupled climate models in simulating extreme temperature and precipitation indices. It is found that the models have certain abilities to simulate both the spatial distributions of extreme climate indices and their trends in the observed period. The models’ abilities are higher overall for extreme temperature indices than for extreme precipitation indices. The well-simulated temperature indices are frost days (Fd), heat wave duration index (HWDI) and annual extreme temperature range (ETR). The well-simulated precipitation indices are the fraction of annual precipitation total due to events exceeding the 95th percentile (R95T) and simple daily intensity index (SDII). In a general manner, the multi-model ensemble has the best skill. For the projections of the extreme temperature indices, trends over the twenty-first century and changes at the end of the twenty-first century go into the same direction. Both frost days and annual extreme temperature range show decreasing trends, while growing season length, heat wave duration and warm nights show increasing trends. The increases are especially manifested in the Tibetan Plateau and in Southwest China. For extreme precipitation indices, the end of the twenty-first century is expected to have more frequent and more intense extreme precipitation. This is particularly visible in the middle and lower reaches of the Yangtze River, in the Southeast coastal region, in the west part of Northwest China, and in the Tibetan Plateau. In the meanwhile, accompanying the decrease in the maximum number of consecutive dry days in Northeast and Northwest, drought situation will reduce in these regions. 相似文献
5.
基于中国均一化气温数据集CN05.1的观测数据,结合暖昼指数（TX90）、冷昼指数（TX10）、暖夜指数（TN90）、冷夜指数（TN10）、暖日持续指数（WSDI）和冷日持续指数（CSDI）6个极端温度指数,从气候平均、概率分布、年际变率和年际趋势方面,系统评估区域气候模式（Climate–Weather Research and Forecasting model, CWRF）对1980～2015年间我国极端温度指数区域分布和年际变化的模拟能力,为改进并利用模式研究我国未来区域极端温度的预测提供科学依据。结果显示:观测的冷暖指数在北方的年际变率幅度高于南方,其中暖指数在我国大部分地区为增暖趋势,冷指数在北方地区的变冷趋势显著,尤其暖夜增暖、冷夜变冷,极端暖事件（WSDI）的持续性比冷事件（CSDI）显著。CWRF模式较好再现了极端温度指数的年均分布和年际变化趋势特征,尤其对暖日和冷日持续指数的模拟优势显著,但仍存在系统性的区域偏差,如低估暖昼和冷夜的极值强度;对华东地区暖（冷）指数变暖（冷）的趋势存在低（高）估;尤其是低估青藏高原地区暖、冷指数的强度,并且高估其暖昼变冷、暖夜变暖的年际变化趋势。因此,该模式对华东及高原地区极端温度的强度和年际变率的模拟仍亟需改善。 相似文献
6.
Huaijun Wang Yaning Chen Shi Xun Dongmei Lai Yuting Fan Zhi Li 《Theoretical and Applied Climatology》2013,112(1-2):15-28
There has been a paucity of information on trends in daily climate and climate extremes, especially for the arid region. We analyzed the changes in the indices of climate extremes, on the basis of daily maximum and minimum air temperature and precipitation at 59 meteorological stations in the arid region of northwest China over the period 1960–2003. Twelve indices of extreme temperature and six indices of extreme precipitation are examined. Temperature extremes show a warming trend with a large proportion of stations having statistically significant trends for all temperature indices. The regional occurrence of extreme cool days and nights has decreased by ?0.93 and ?2.36 days/decade, respectively. Over the same period, the occurrence of extreme warm days and nights has increased by 1.25 and 2.10 days/decade, respectively. The number of frost days and ice days shows a statistically significant decrease at the rate of ?3.24 and ?2.75 days/decade, respectively. The extreme temperature indices also show the increasing trend, with larger values for the index describing variations in the lowest minimum temperature. The trends of Min Tmin (Tmax) and Max Tmin (Tmax) are 0.85 (0.61) and 0.32 (0.17)?°C/decade. Most precipitation indices exhibit increasing trends across the region. On average, regional maximum 1-day precipitation, annual total wet-day precipitation, and number of heavy precipitation days and very wet days show insignificant increases. Insignificant decreasing trends are also found for consecutive dry days. The rank-sum statistic value of most temperature indices exhibits consistent or statistically significant trends across the region. The regional medians after 1986 of Min Tmin (Tmax), Max Tmin (Tmax), warm days (nights), and warm spell duration indicator show statistically more larger than medians before 1986, but the frost days, ice days, cool days (nights), and diurnal temperature range reversed. The medians of precipitation indices show insignificant change except for consecutive dry days before and after 1986. 相似文献
7.
Jose A. Marengo Matilde Rusticucci Olga Penalba Madeleine Renom 《Climatic change》2010,98(3-4):509-529
We analyze historical simulations of variability in temperature and rainfall extremes in the twentieth century, as derived from various global models run informing the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC-AR4). On the basis of three indices of climate extremes, we compare observed and modeled trends in time and space, including the direction and significance of the changes at the scale of South America south of 10° S. The climate extremes described warm nights, heavy rainfall amounts and dry spells. The reliability of the GCM simulations is suggested by similarity between observations and simulations in the case of warm nights and extreme rainfall in some regions. For any specific extreme temperature index, minor differences appear in the spatial distribution of the changes across models in some regions, while substantial differences appear in regions in the interior of tropical and subtropical South America. The differences are in the relative magnitude of the trends. Consensus and significance are less strong when regional patterns are considered, with the exception of the La Plata Basin, where observed and simulated trends in warm nights and extreme rainfall are evident. 相似文献
8.
选用世界气象组织公布的极端气候指数方法对1961—2009年黑龙江省8个极端气温指数进行计算和分析,得到黑龙江省极端气温事件的事实和变化特征。结果表明：黑龙江省近49年来夏日天数、极端最低气温、极端最高气温、暖夜指数和暖昼日数均呈上升趋势,而霜冻日数、冷夜指数和冷昼日数呈下降趋势。极端气温指数的变化存在明显的年际变化特征,并有突变发生。对黑龙江省气温升高来说,最低气温升高主要发生在20世纪80年代中期以后,而最高气温则在90年代以后上升明显。空间分布方面,极端气温指数在全区基本都呈一致的增大或减小分布。夜间增暖的幅度要大于白天增暖的幅度,夜间气温的上升对增暖的贡献更大。 相似文献
9.
Multidecadal changes in the relationship between extreme temperature events in Uruguay and the general atmospheric circulation 总被引：1，自引：0，他引：1
We analyze changes in the relationship between extreme temperature events and the large scale atmospheric circulation before and after the 1976 climate shift. To do so we first constructed a set of two temperature indices that describe the occurrence of warm nights (TN90) and cold nights (TN10) based on a long daily observed minimum temperature database that spans the period 1946?C2005, and then divided the period into two subperiods of 30?years each (1946?C1975 and 1976?C2005). We focus on summer (TN10) and winter (TN90) seasons. During austral summer before 1976 the interannual variability of cold nights was characterized by a negative phase of the Southern Annular Mode (SAM) with a cyclonic anomaly centered off Uruguay that favoured the entrance of cold air from the south. After 1976 cold nights are associated not with the SAM, but with an isolated vortex at upper levels over South Eastern South America. During austral winter before 1976, the El Ni?o phenomenon dominated the interannual variability of warm nights through an increase in the northerly warm flow into Uruguay. However, after 1976 the El Ni?o connection weakened and the variability of warm nights is dominated by a barotropic anticyclonic anomaly located in the South Atlantic and a low pressure center over South America. This configuration also strengthens the northward flow of warm air into Uruguay. Our results suggest that changes in El Ni?o evolution after 1976 may have played a role in altering the relationship between temperature extreme events in Uruguay and the atmospheric circulation. 相似文献
10.
This paper reports a comprehensive study on the observed and projected spatiotemporal changes in mean and extreme climate over the arid region of northwestern China, based on gridded observation data and CMIP5 simulations under the RCP4.5 and RCP8.5 scenarios. The observational results reveal an increase in annual mean temperature since 1961, largely attributable to the increase in minimum temperature. The annual mean precipitation also exhibits a significant increasing tendency. The precipitation amount in the most recent decade was greater than in any preceding decade since 1961. Seasonally,the greatest increase in temperature and precipitation appears in winter and in summer, respectively. Widespread significant changes in temperature-related extremes are consistent with warming, with decreases in cold extremes and increases in warm extremes. The warming of the coldest night is greater than that of the warmest day, and changes in cold and warm nights are more evident than for cold and warm days. Extreme precipitation and wet days exhibit an increasing trend, and the maximum number of consecutive dry days shows a tendency toward shorter duration. Multi-model ensemble mean projections indicate an overall continual increase in temperature and precipitation during the 21 st century. Decreases in cold extremes, increases in warm extremes, intensification of extreme precipitation, increases in wet days, and decreases in consecutive dry days, are expected under both emissions scenarios, with larger changes corresponding to stronger radiative forcing. 相似文献
11.
Concepción Rodríguez-Puebla Ascensión H. Encinas Luis Alberto García-Casado Susana Nieto 《Climatic change》2010,100(3-4):667-684
The aims of this study are to identify the trend of warm days and cold nights over the Iberian Peninsula and to connect the variations with large-scale variables. The reasons for performing this analysis are the effects that extremes events have on different ecosystems. Here, we present the results on spatial and temporal variability of warm days (TX90), or those exceeding the 90th percentile of maximum temperature, and cold nights (TN10), or those falling below the 10th percentile of minimum temperature. The extreme indices were derived from daily observations at stations and gridded data over land area for the period 1950 to 2006. Significant trends of more warm days and fewer cold nights were found. The trend to fewer cold nights is within the interval of global results given by the IPCC AR4 report; however, the trend to warm days is greater than the corresponding global trend. The influence of large-scale variables on these extreme indices was examined by means of the Empirical Orthogonal Function, correlation, composite maps and multiple regression analyses. Changes in TX90 are connected with the Scandinavian teleconnection index and a preferred mode of geopotential height at 500 hPa over the North Atlantic. Changes in TN10 are connected with the East Atlantic teleconnection index and the leading mode of Sea Surface Temperature (SST) variability over the North Atlantic area. Based on the links between the extreme indices and the large-scale variables we derived statistical models to describe the response of TX90 and TN10 to atmospheric circulation and SST variations. The models characterized the observed variations of TX90 and TN10 reasonably well. The results of this study encourage us to analyze, in further work, how temperature extremes might change over the Iberian Peninsula under warmer climate conditions. 相似文献
12.
The simulation of extreme weather indices with the INM-CM5 and INMCM4 climate models for modern climate which were developed in the Institute of Numerical Mathematics of Russian Academy of Sciences is considered. It is shown that the INM-CM5 model improved the simulation of almost all indices concerning temperature (especially to its minimum values) and precipitation (mean total precipitation, mean precipitation intensity) extremes and concerning consecutive dry days and consecutive wet days. At the same time, the simulation of indices connected with extreme heavy precipitation became worse. It was found that this shortcoming can be minimized by introducing the vertical mixing of horizontal wind for the large-scale condensation and deep convection. 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.
Indices for temperature and precipitation extremes are calculated on the basis of the global climate model ECHAM5/MPI-OM simulations
of the twentieth century and SRES A1B and B1 emission scenarios for the twenty-first century. For model evaluation, the simulated
indices representing the present climate were compared with indices based on observational data. This comparison shows that
the model is able to realistically capture the observed climatological large-scale patterns of temperature and precipitation
indices, although the quality of the simulations depends on the index and region under consideration. In the climate projections
for the twenty-first century, all considered temperature-based indices, minimum Tmin, maximum Tmax, and the frequency of tropical
nights, show a significant increase worldwide. Similarly, extreme precipitation, as represented by the maximum 5-day precipitation
and the 95th percentile of precipitation, is projected to increase significantly in most regions of the world, especially
in those that are relatively wet already under present climate conditions. Analogously, dry spells increase particularly in
those regions that are characterized by dry conditions in present-day climate. Future changes in the indices exhibit distinct
regional and seasonal patterns as identified exemplarily in three European regions. 相似文献
15.
利用1951—2009年天津市逐日气温和降水量资料,计算了极端气候指数,并研讨了其中11个主要指数的变化特征。结果表明：天津市暖日、冷夜具有基本相反的变化趋势,暖日显著增加,冷夜显著减少,且冷夜的变化幅度远大于暖日。持续暖期、霜日呈显著增加趋势,持续冷期呈显著减少趋势。降水指数中连续干日呈增加趋势,最大连续5 d降水量、日降水强度、强降水率和极强降水率及连续湿日均呈减少趋势,表明天津市干旱化倾向明显。与气温有关的极端指数大多在1993年前后出现突变,周期特征不明显。与降水有关的极端指数未现突变,但周期特征明显,大多出现10 a和4 a的周期。 相似文献
16.
Ramón Fuentes-Franco Erika Coppola Filippo Giorgi Federico Graef Edgar G. Pavia 《Climate Dynamics》2014,42(3-4):629-647
The skill of a regional climate model (RegCM4) in capturing the mean patterns, interannual variability and extreme statistics of daily-scale temperature and precipitation events over Mexico is assessed through a comparison of observations and a 27-year long simulation driven by reanalyses of observations covering the Central America CORDEX domain. The analysis also includes the simulation of tropical cyclones. It is found that RegCM4 reproduces adequately the mean spatial patterns of seasonal precipitation and temperature, along with the associated interannual variability characteristics. The main model bias is an overestimation of precipitation in mountainous regions. The 5 and 95 percentiles of daily temperature, as well as the maximum dry spell length are realistically simulated. The simulated distribution of precipitation events as well as the 95 percentile of precipitation shows a wet bias in topographically complex regions. Based on a simple detection method, the model produces realistic tropical cyclone distributions even at its relatively coarse resolution (dx = 50 km), although the number of cyclone days is underestimated over the Pacific and somewhat overestimated over the Atlantic and Caribbean basins. Overall, it is assessed that the performance of RegCM4 over Mexico is of sufficient quality to study not only mean precipitation and temperature patterns, but also higher order climate statistics. 相似文献
17.
Xuejie GAO Ying SHI Zhenyu HAN Meili WANG Jia WU Dongfeng ZHANG Ying XU Filippo GIORGI 《大气科学进展》2017,34(4):441-455
A long-term simulation for the period 1990–2010 is conducted with the latest version of the International Centre for Theoretical Physics' Regional Climate Model(RegCM4), driven by ERA-Interim boundary conditions at a grid spacing of 25 km. The Community Land Model(CLM) is used to describe land surface processes, with updates in the surface parameters,including the land cover and surface emissivity. The simulation is compared against observations to evaluate the model performance in reproducing the present day climatology and interannual variability over the 10 main river basins in China,with focus on surface air temperature and precipitation. Temperature and precipitation from the ERA-Interim reanalysis are also considered in the model assessment. Results show that the model reproduces the present day climatology over China and its main river basins, with better performances in June–July–August compared to December–January–February(DJF).In DJF, we find a warm bias at high latitudes, underestimated precipitation in the south, and overestimated precipitation in the north. The model in general captures the observed interannual variability, with greater skill for temperature. We also find an underestimation of heavy precipitation events in eastern China, and an underestimation of consecutive dry days in northern China and the Tibetan Plateau. Similar biases for both mean climatology and extremes are found in the ERA-Interim reanalysis, indicating the difficulties for climate models in simulating extreme monsoon climate events over East Asia. 相似文献
18.
Christopher J. White Kathleen L. McInnes Robert P. Cechet Stuart P. Corney Michael R. Grose Gregory K. Holz Jack J. Katzfey Nathaniel L. Bindoff 《Climate Dynamics》2013,41(11-12):3145-3165
The ability of an ensemble of six GCMs, downscaled to a 0.1° lat/lon grid using the Conformal Cubic Atmospheric Model over Tasmania, Australia, to simulate observed extreme temperature and precipitation climatologies and statewide trends is assessed for 1961–2009 using a suite of extreme indices. The downscaled simulations have high skill in reproducing extreme temperatures, with the majority of models reproducing the statewide averaged sign and magnitude of recent observed trends of increasing warm days and warm nights and decreasing frost days. The warm spell duration index is however underestimated, while variance is generally overrepresented in the extreme temperature range across most regions. The simulations show a lower level of skill in modelling the amplitude of the extreme precipitation indices such as very wet days, but simulate the observed spatial patterns and variability. In general, simulations of dry extreme precipitation indices are underestimated in dryer areas and wet extremes indices are underestimated in wetter areas. Using two SRES emissions scenarios, the simulations indicate a significant increase in warm nights compared to a slightly more moderate increase in warm days, and an increase in maximum 1- and 5-day precipitation intensities interspersed with longer consecutive dry spells across Tasmania during the twenty-first century. 相似文献
19.
利用1986—2005年中国地面气象台站观测的格点化逐日降水数据(CN05.1)评估了NASA高分辨率降尺度逐日数据集NEX-GDDP中21个全球气候模式在0.25?(约25 km×25 km)分辨率下对中国极端降水的模拟能力.选取年最大日降水量(RX1D)、年最大5 d降水量(RX5D)、湿日总降水量(PRCPTOT... 相似文献
20.
不同升温阈值下中国地区极端气候事件变化预估 总被引：6，自引：1，他引：5
本文基于耦合模式比较计划第五阶段(CMIP5)的18个全球气候模式的模拟结果,预估了全球平均气温在不同典型浓度路径(RCPs)下达到2℃、3℃和4℃阈值时,中国地区气温和降水的变化,并采用了具有稳定统计意义的27个极端气候指标定量评估了全球平均气温达到不同阈值时,中国地区极端气候事件的可能变化。结果表明,未来我国平均气温增幅将高于全球平均增暖,极端暖事件(如暖夜、暖昼、热带夜)明显增多,达到4℃阈值时,暖夜指数相比参考时段增加约49.9%。极端冷事件(如冷夜、冷昼、霜冻)减少。随全球气温升高,中国北方平均降水增多。在不同升温阈值下,中国地区降水的极端性都体现出增强的趋势,强降水事件发生频率(如中雨日数、大雨日数)和强度(如五日最大降水量、极端强降水量)都明显增加。随升温阈值的升高,这些变化幅度更大,在 RCP8.5 情景下全球升温 3℃和4℃时,中国平均五日最大降水分别增加 12.5mm和17.0mm。我国西南地区极端降水强度的增幅高于其他地区。 相似文献