Homogenization of climate series:The basis for assessing climate changes     

YAN ZhongWei  LI Zhen  XIA JiangJiang 《中国科学:地球科学(英文版)》2014,(12)

Long-term meteorological observation series are fundamental for reflecting climate changes.However,almost all meteorological stations inevitably undergo relocation or changes in observation instruments,rules,and methods,which can result in systematic biases in the observation series for corresponding periods.Homogenization is a technique for adjusting these biases in order to assess the true trends in the time series.In recent years,homogenization has shifted its focus from the adjustments to climate mean status to the adjustments to information about climate extremes or extreme weather.Using case analyses of ideal and actual climate series,here we demonstrate the basic idea of homogenization,introduce new understanding obtained from recent studies of homogenization of climate series in China,and raise issues for further studies in this field,especially with regards to climate extremes,uncertainty of the statistical adjustments,and biased physical relationships among different climate variables due to adjustments in single variable series.  相似文献   

将灾害风险管理和适应气候变化纳入可持续发展   总被引：1，自引：0，他引：1       下载免费PDF全文

郑艳 《气候变化研究进展》2012,8(2):103-109

IPCC发布的《管理极端事件和灾害风险,推进气候变化适应》特别报告(SREX)指出,极端事件和灾害的影响很大程度上取决于社会经济系统的风险暴露程度及其脆弱性特征。这意味着,不合理的发展过程将加剧灾害风险及其损失,另一方面,采取积极的减灾和适应行动,能够减小灾害风险并促进社会、经济、环境的可持续发展。SREX报告有助于启发决策者与社会公众,为充满不确定风险的未来进行合理规划,包括关注未来因人口和社会财富增长导致的暴露度和脆弱性增加,在国家和部门层面整合适应、减灾与发展政策,利用多种政策工具加强决策的科学性和灵活性,发挥不同主体在适应治理与灾害风险管理中的作用等等。  相似文献   

梅雨期江淮地区极端高温事件的非均匀性特征及其与环流系统的配置   总被引：1，自引：0，他引：1       下载免费PDF全文

朱坚  黄丹青  钱永甫  林惠娟 《地球物理学报》2010,53(10):2310-2320

本文基于集中度和集中期的定义方法,利用1960~2007年的48年江淮地区站点的日平均温度资料和累积频率的阈值统计方法,分析梅雨期江淮地区极端高温事件的非均匀分布特征.结果表明,集中度和集中期的方法能够定量地表征梅雨期江淮地区极端高温事件的非均匀分布特征.集中期的异常型为全场一致和南北异常型,集中度的异常分布主要为南北异常和东西异常.进一步比较集中度和集中期异常与同期环流系统的配置关系得知,当集中期南北异常变化时,在高纬度的北太平洋区域出现一对正负的异常模态,且随高度增加而增强,为相当正压结构.海温的异常集中在北太平洋的北美沿岸的显著负异常中心.当集中度为东西异常时,主要环流异常型为约在160°W左右出现 "+ - + -" 的200 hPa纬向西风异常波列形式从低纬度到高纬度地区传播以及与ENSO的显著负相关.  相似文献   

增暖背景下中国东北地区极端降水事件的演变特征   总被引：15，自引：5，他引：10  

杨素英  孙凤华  马建中 《地理科学》2008,28(2):224-228

利用中国东北地区93站1959~2002年逐日降水资料,研究该区极端降水事件时空演变特征,结果表明:东北地区极端降水事件阈值由东南沿海向西北内陆逐渐减小,6~9月是极端降水事件集中出现月份;1985~2002年是极端降水事件偏多,且为一突变现象;东北地区短时间内连续发生极端降水事件概率较大,其中1~5天时间间隔极端降水事件占23.7%;80年代中期后东北地区增暖背景下,极端降水事件和有1~5天时间间隔的极端降水事件明显增加,特别是松花江下游和牡丹江流域及西辽河上游地区,频次和强度存在增加或增强趋势。  相似文献   

Quo vadis,hydrology?     

Zbigniew W. Kundzewicz 《水文科学杂志》2018,63(8):1118-1132

This is an invited essay by the Dooge Medallist of the 2017 International Hydrological Prize. The paper reflects a broad perspective on hydrology, as a result of the author’s long experience. It is suggested that transgressing the traditional hydrological perspective, by increasing the scale of research, as well as interdisciplinarization have been, and are likely to remain, key drivers of the development of hydrology. Gaps in knowledge and research challenges are reviewed, and the interlinked areas of stationarity, extremes and projections for the future are discussed. Finally, after reviewing the achievements of Jim Dooge, examples of others following in his footsteps are presented.  相似文献   

A Two-plume Convective Model for Precipitation Extremes     

Zihan YIN  Panxi DAI  Ji NIE 《大气科学进展》2021,38(6):957-965

In the study of diagnosing climate simulations and understanding the dynamics of precipitation extremes, it is an essential step to adopt a simple model to relate water vapor condensation and precipitation, which occur at cloudmicrophysical and convective scales, to large-scale variables. Several simple models have been proposed; however,improvement is still needed in both their accuracy and/or the physical basis. Here, we propose a two-plume convective model that takes into account the subgrid inhomogeneity of precipitation extremes. The convective model has three components, i.e., cloud condensation, rain evaporation, and environmental descent, and is built upon the zero-buoyancy approximation and guidance from the high-resolution reanalysis. Evaluated against the CMIP5 climate simulations, the convective model shows large improvements in reproducing precipitation extremes compared to previously proposed models. Thus, the two-plume convective model better captures the main physical processes and serves as a useful diagnostic tool for precipitation extremes.  相似文献   

2021: A Year of Unprecedented Climate Extremes in Eastern Asia,North America,and Europe     

Tianjun ZHOU  Wenxia ZHANG  Lixia ZHANG  Robin CLARK  Cheng QIAN  Qinghong ZHANG  Hui QIU  Jie JIANG  Xing ZHANG 《大气科学进展》2022,39(10):1598-1607

The year 2021 was recorded as the 6th warmest since 1880. In addition to large-scale warming, 2021 will be remembered for its unprecedented climate extremes. Here, a review of selected high-impact climate extremes in 2021, with a focus on China, along with an extension to extreme events in North America and Europe is presented. Nine extreme events that occurred in 2021 in China are highlighted, including a rapid transition from cold to warm extremes and sandstorms in spring, consecutive drought in South China and severe thunderstorms in eastern China in the first half of the year, extremely heavy rainfall over Henan Province and Hubei Province during summer, as well as heatwaves, persistent heavy rainfall, and a cold surge during fall. Potential links of extremes in China to four global-scale climate extremes and the underlying physical mechanisms are discussed here, providing insights to understand climate extremes from a global perspective. This serves as a reference for climate event attribution, process understanding, and high-resolution modeling of extreme events.  相似文献   

Spatial distribution and temporal trends of mean precipitation and extremes in the arid region,northwest of China,during 1960–2010     

Huaijun Wang  Yaning Chen  Zhongsheng Chen 《水文研究》2013,27(12):1807-1818

On the basis of daily precipitation records at 76 meteorological stations in the arid region, northwest of China, the spatial and temporal distribution of mean precipitation and extremes were analysed during 1960–2010. The Mann–Kendall trend test and linear least square method were utilized to detect monotonic trends and magnitudes in annual and seasonal mean precipitation and extremes. The results obtained indicate that both the mean precipitation and the extremes have increased except in consecutive dry days, which showed the opposite trend. The changes in amplitude of both mean precipitation and extremes show seasonal variability. On an annual basis, the number of rain days (R0.1) has significantly increased. Meanwhile, the precipitation intensity as reflected by simple daily intensity index (SDII), number of heavy precipitation days (R10), very wet days (R95p), max 1‐day precipitation amount (RX1day) and max 5‐day precipitation amount (RX5day) has also significantly increased. This suggests that the precipitation increase in the arid region is due to the increase in both precipitation frequency and intensity. Trends in extremes are very highly correlated with mean trends of precipitation. The spatial correlation between trends in extremes and trends in the mean is stronger for winter (DJF) than for annual and other seasons. The regional annual and seasonal precipitation and extremes are observed the step jump in mean in the late 1980s. Overall, the results of this study are good indicators of local climate change, which will definitely enhance human mitigation to natural hazards caused by precipitation extremes. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Prediction of the impact of climate change on drought: an evaluation of six UK catchments using two stochastic approaches     

Christian Onof 《水文研究》2013,27(11):1600-1614

Under future climate scenarios, possible changes of drought patterns pose new challenges for water resources management. For quantifying and qualifying drought characteristics in the UK, the drought severity indices of six catchments are investigated and modelled by two stochastic methods: autoregressive integrated moving average (ARIMA) models and the generalized linear model (GLM) approach. From the ARIMA models, autocorrelation structures are first identified for the drought index series, and the unexplained variance of the series is used to establish empirical relationships between drought and climate variables. Based on the ARIMA results, mean sea level pressure and possibly the North Atlantic Oscillation index are found to be significant climate variables for seasonal drought forecasting. Using the GLM approach, occurrences and amounts of rainfall are simulated with conditioning on climate variables. From the GLM‐simulated rainfall for the 1980s and 2080s, the probabilistic characteristics of the drought severity are derived and assessed. Results indicate that the drought pattern in the 2080s is less certain than for the 1961–1990 period, based on the Shannon entropy, but that droughts are expected to be more clustered and intermittent. The 10th and 50th quantiles of drought are likely higher in the 2080s scenarios, but there is no evidence showing the changes in the 90th quantile extreme droughts. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

基于MF-DFA的西安昼夜复合高温事件变化特征及影响因素     

李双双  王婷 《干旱区地理》2022,45(1):103-112

采用随机重排去趋势波动分析(MF-DFA)和极点对称模态分解法(ESMD),对1955—2019年西安市昼夜复合高温事件变化特征进行分析.结果表明:(1)气象站点迁移,造成对西安市极端高温变化趋势低估.其中,最高温原始数据与订正序列阈值相同;订正后,最低温阈值相对偏低0.2～0.5℃.(2)MF-DFA、90.0％和9...  相似文献