An overview of mainland China temperature change research

There has been significant effort devoted to investigating long-term trends in land surface air temperature over mainland China by Chinese scientists over the past 50 years, and much progress has been made in understanding dynamics of the changes. This review highlights research conducted by early Chinese climatologists, and particularly Professor Shaowu Wang from Peking University, with special focus on systematic work that has been conducted since the mid to late 1970s. We also discuss major issues that remain unresolved in past and current studies. The most recent analyses indicate that the country-average annual mean surface air temperature rose by 1.12°C over the past 115 years (1901–2015), with a rate of increase of about 0.10°C decade^–1. Temperatures have risen more rapidly since the 1950s, with the rate of increase of more than 0.25°C decade^-1. However, the recent increase in temperatures is in large part due to contamination by systematically biased data. These data are influenced by unprecedented urbanization in China, with a contribution of urbanization to the overall increase of annual mean temperatures in mainland China of about one third over the past half a century. If the bias is corrected, the rate of increase for the country-average annual mean surface air temperature is 0.17°C decade–1 over the last 50–60 years, which is approximately the same as global and Northern Hemispheric averages in recent decades. Future efforts should be focused towards the recovery and digitization of early-year observational records, the homogenization of observational data, the evaluation and adjustment of urbanization bias in temperature data series from urban stations, the analysis of extreme temperatures over longer periods including the first half of the 20th century, and the investigation of the observed surface air temperature change mechanisms in mainland China.     

华北地区小时极端降水的非稳态研究

本文以华北五省为研究区,基于1960—2014年小时降水数据建立1、2、3、6、12和24 h极端降水序列,对比分析稳态和非稳态假设下极端降水重现期估计的差异。研究表明：1960―2014年华北不同时间极端降水的变化趋势略有不同,时间越短呈上升趋势的站点越多,1~3 h的极端降水呈上升趋势的站点较多,稳态和非稳态假设下的20~100 a一遇重现期平均差异较大,其中,1 h极端降水的显著上升站点中,二者的平均相对误差达30%~43%;而6~24 h极端降水中,呈下降趋势的站点增多,其中,24 h极端降水显著下降站点中,二者的平均相对误差达-43%~-32%;无显著趋势站点,二者的平均相对误差大部分介于-10%~10%。随着重现期增大,二者差异的不确定性区间增大,不同变化趋势站点表现一致。研究发现,华北地区短历时极端降水强度增加,稳态假设下极端降水的重现期会严重低估。因此,选用非稳态假设估计极端降水的重现期,将降低极端降水的灾害风险。     

影响中国大陆热带气旋路径分类及其特征研究

热带气旋(TC)是影响中国的重要天气系统,对TC路径分类有助于认识热带气旋的活动特征。本文采用中国气象局热带气旋资料中心提供的1949至2016年6—11月最佳TC路径资料,选取TC质心、生命史、转向、强度等特征参数,利用K-means聚类方法将影响中国大陆的热带气旋分为4类。对4类路径进行比对分析后发现各类TC的走向、生命史、活动季节、登陆概率及区域等特征差异显著,TC单体强度和生命史在强厄尔尼诺发展年也有不同程度的增强。在年代际变化上,1998年以来,尽管各类TC频数变化趋势不同,但各类TC单体能量耗散指数均有不同程度的增长趋势,这可能与近年来强厄尔尼诺发展有关。     

Spatial-temporal characteristics of temperature variation in China

Summary Spatial-temporal characteristics of temperature variations were analyzed from China daily temperature based on 486 stations during the period 1960–2000. The method of hierarchical cluster analysis was used to divide the territory into sub-regional areas with a coherent evolution, both annually and seasonally. Areas numbering 7–9 are chosen to describe the regional features of air temperature in mainland China. All regions in mainland China experienced increasing trends of annual mean temperature. The trend of increasing temperature was about 0.2–0.3 °C/10 yr in northern China and less than 0.1 °C/10 yr in southern China. In the winter season, the increasing trend of temperature was about 0.5–0.7 °C/10 yr in northern China and about 0.2–0.3 °C/10 yr in southern China. The increasing trend of autumn temperature was mainly located in northwestern China and southwestern China including the Tibetan Plateau. In spring, the rising trend of temperature was concentrated in Northeast China and North China while there was a declining temperature trend of −0.13 °C/10 yr in the upper Yangtze River. In summer, the declining trend of temperature was only concentrated in the mid-low valley of the Yangtze and Yellow Rivers while surrounding this valley there were increasing trends in South China, Southwest China, Northwest China, and Northeast China. Rapid changes in temperature in various regions were detected by the multiple timescale t-test method. The year 1969 was a rapid change point from a high temperature to a low temperature along the Yangtze River and South China. In the years 1977–1979, temperature significantly increased from a lower level to a higher level in many places except for regions in North China and the Yangtze River. Another rapid increasing temperature trend was observed in 1987. In the years 1976–1979, a positive rapid change of summer temperature occurred in northwestern China and southwestern China while a decreasing temperature was found between the Yellow River and the Yangtze River. A rapid increase of winter temperature was found for 1977–1979 and 1985–1986 in many places. There were increasing events of extreme temperature in broad areas except in the north part of Northeast China and the north part of the Xinjiang region. In winter, increasing temperature of the climate state and weakening temperature extremes are observed in northern China. In summer, both increasing temperature of the climate state and enhancing temperature extremes were commonly exhibited in northern China. Present address: Linfen Meteorological Office, Linfen 041000, Shanxi Province, China.     

Change features and regional distribution of temperature trend and variability joint mode in mainland China

Theoretical and Applied Climatology - Adaption for temperature should be suitable to local conditions for regional differences in temperature change features. This paper proposed to utilize nine...     

近60年中国探空观测气温变化趋势及不确定性研究

基于118站探空资料研究了近60年中国850—100 hPa气温变化趋势及季节和区域特征,并通过与1979—2017年卫星微波气温的对比研究了中国探空气温均一化的不确定性。研究表明,1958—2017年中国平均对流层气温呈上升趋势,300 hPa升温最为显著,平流层下层（100 hPa）为降温趋势。冬季对流层上层升温趋势和夏季平流层下层降温趋势较强。1979—2017年较整个时段对流层升温趋势较强,平流层下层降温趋势较弱。青藏高原和西北地区对流层上层升温趋势较强。通过与卫星微波气温和邻近探空站探空气温的对比以及均一化前后日夜气温差值检测出中国探空均一化气温仍残存非均一性问题。由于参照序列的局限性,均一化未能完全去除21世纪最初10年中国探空系统变化造成的对流层中、上层至平流层下层气温系统性下降的影响,导致中国对流层上层升温趋势被低估和平流层下层降温趋势被高估。未来可通过参考卫星微波气温和邻近探空站序列调整非均一性订正顺序并增加合理性检验等方法改进中国探空气温均一化方案。      

中国雨日数的气候特征及趋势变化

使用国家气象信息中心整编的全国2 425个观测站1961年1月—2013年2月的52 a逐日降水观测资料,美国气象环境预报中心(NCEP)和美国国家大气研究中心(NCAR)资料。通过计算气候场、雨日概率、倾向值、M-K突变检验等现代统计诊断方法,研究了中国各等级雨日数的年、季节的时空分布特征和不同等级雨日数的趋势变化特征以及相关的背景环流。得到以下结论:(1)中国年总雨日数高值区在四川东部、贵州、江南及云南西南部,以小雨日数占比最高;中雨、大雨日数高值区在江南东部和云南西南部;50 mm以上雨日数中心分别在华南沿海和闽—浙—赣交界,前者强后者弱;(2)年内总雨日概率分布表现为3类:平缓型、单峰型、双峰型,南方地区除云南外均为平缓型;西藏东部、川西、陕甘宁3省南部、青海东部为双峰型;全国其余地区为单峰型;(3)中国季风区小雨日数在1970s末—1980s初发生突变,呈趋势性显著减少,除东北外,四季均减少,以秋冬季云南、上海等地减少最显著,而干旱半干旱区小雨日数呈增加趋势;(4)西南地区东部的年中雨日数在2000年后显著减少,秋季减少最明显,而京、沪、粤3大城市群年中雨日数呈增加趋势;西南地区东部秋季、云南夏季大雨以上日数在2003年后显著减少,而夏冬两季长江中下游中雨以上等级的雨日数明显增加;(5)川东、贵州、江南中部的雨日高值区与青藏高原东部低层回流冷空气形成的静止锋或辐合带相联系。     

中国地气温差时空分布及变化趋势

利用中国825个气象站点1961—2016年的逐日地表温度和气温观测资料,系统分析了中国地区地气温差（地表温度减气温）的时空分布以及变化趋势。结果表明,中国多年平均的年地气温差西部大部地区及华南部分地区在2.5℃以上,而中东部大部地区在2.5℃以下。其中春、夏季全国各地地气温差均为正值,且总体呈经向型分布,西高东低;秋、冬季中国各地地气温差总体呈纬向型分布,南高北低,尤其是冬季北方部分地区为负值。年内,中国区域平均各月地气温差均为正值,其中1月份和12月份相对较小,6—8月份（夏季）相对较大。不同地区地气温差的年内分布特征有所不同,西藏地区地气温差年平均值为全国最大,最大值出现在雨季来临前的5月份;东北、华北、黄淮、西北及内蒙古地区最大值均出现在雨季来临前的6月份;江淮、江汉、江南、华南地区地气温差最大值均出现在雨季过后的7月份或8月份;西南地区年内各月地气温差变化相对较小,在雨季之前的5月和雨季之后的8月出现2次峰值,呈双峰型分布。1961—2016年,中国区域平均地气温差4月和4—10月上升趋势较明显,而7月和10月变化趋势不明显或略有上升趋势。空间分布上,东北、西北及内蒙古、西藏西部等地平均地气温差有增加趋势,而中东部地区有减小趋势。     

中国东部地区城市化对气温影响的观测分析

现有场地观测表明,城市化对于气温的影响在静风、无云条件下的晚上最明显,而在大风、多云条件下的晚上最小.本文采用一套经过均一化处理的中国地区逐日平均、最高以及最低气温序列资料集,分析了中国东部地区在不同风速、云量条件下地面气温变化的趋势.结果表明,从1960-2008年,中国东部地区(20～45° N,110～125° ...     

中国地面气温变化趋势中的城市化影响偏差

在中国大陆2300个气象台站网中遴选出138个参考站,对614个国家级气象站和138个参考站1961 2004年的月平均气温资料进行了非均一性检验和订正,利用REOF(旋转主分量)分析方法,按照气温变率空间相关特点将中国大陆划分为6大区域,并采用经纬度网格面积加权平均法分别建立了中国大陆及其6大区域平均的国家站和参考站的月、季、年地面气温时间序列,对国家站和参考站序列进行了对比分析。结果表明,由国家站资料建立的中国大陆年平均气温序列在44年间线性增温率为0.278 C/10 a,而由参考站资料建立的中国大陆年平均气温序列同期增温率为0.202℃/10 a。就中国大陆平均来说,1961 2004年国家级站城市化增温率为0.076 C/10 a,占全部增温率的27.33%。在6大区域中,除北疆区外,其他地区年平均城市化增温率均非常显著。其中城市化影响最大的地区是江淮区,年平均热岛增温率为0.086℃/10 a,其后依次为东北华北区、青藏高原区、华南区和西北区,年平均热岛增温率分别达到0.060、0.059、0.042和0.042℃/10 a。各区域年平均热岛增温贡献率由大到小排列依次为江淮区55.48%、青藏高原区23.23%、华南区23.20%、东北华北区15.35%、西北区13.73%、北疆区-1.57%。因此,中国大陆20世纪60年代初以来城市化造成的国家站地面气温增暖偏差非常显著,今后应予以订正,以便建立代表背景气候变化的区域平均气温序列。     

阿克苏地区短时强降雨时空分布和卫星云图特征

基于2012-2018年风云系列卫星云图资料(红外图像、水汽图像、TBB图像),区域自动站小时降雨资料,高空、地面常规观测资料,统计分析阿克苏地区短时强降雨的时空变化和卫星云图特征.结果表明:(1)短时强降雨主要出现于6-8月的16-20时,空间分布为北部山区最多、浅山区次之、平原及南部沙漠地区最少,降雨强度多为10....     

Change trends of air temperature and precipitation over Shanxi Province, China

A dataset of air temperature and precipitation time series (1959?C2008) from 61 stations across Shanxi, China is used to analyze the climate change. The monotonic trends and step (abrupt) trends for annual and seasonal series data of mean air temperature and total precipitation are tested by using Mann?CKendall test and Mann?CWhitney test, respectively. The results show that annual mean air temperature has increased by 1.20°C during the past 50?years. Winter, spring, and autumn have experienced a significant increase in air temperature. The step trend for annual mean air temperature is different from, but closely related with, those for seasonal mean air temperature. Spatially, there is an enhanced warming trend from south to north in Shanxi, and the most remarkable warming occurs in northern Shanxi. Annual precipitation has decreased by 99.20?mm during the past half century. The decrease is mainly caused by precipitation decline in rainy season (June?CSeptember), though precipitation in post-rainy season (October?CNovember) also tended to decrease. An abrupt decrease in precipitation has occurred since late 1970s. Decrease in precipitation is highest in central Shanxi and in the area along the west fringe between Sanchuan River and Fenhe River in western Shanxi.     

Recent trends in observed temperature and precipitation extremes in the Yangtze River basin,China

Summary The present study is an analysis of the observed extreme temperature and precipitation trends over Yangtze from 1960 to 2002 on the basis of the daily data from 108 meteorological stations. The intention is to identify whether or not the frequency or intensity of extreme events has increased with climate warming over Yangtze River basin in the last 40 years. Both the Mann-Kendall (MK) trend test and simple linear regression were utilized to detect monotonic trends in annual and seasonal extremes. Trend tests reveal that the annual and seasonal mean maximum and minimum temperature trend is characterized by a positive trend and that the strongest trend is found in the winter mean minimum in the Yangtze. However, the observed significant trend on the upper Yangtze reaches is less than that found on the middle and lower Yangtze reaches and for the mean maximum is much less than that of the mean minimum. From the basin-wide point of view, significant increasing trends are observed in 1-day extreme temperature in summer and winter minimum, but there is no significant trend for 1-day maximum temperature. Moreover, the number of cold days ≤0 °C and ≤10 °C shows significant decrease, while the number of hot days (daily value ≥35 °C) shows only a minor decrease. The upward trends found in the winter minimum temperature in both the mean and the extreme value provide evidence of the warming-up of winter and of the weakening of temperature extremes in the Yangtze in last few decades. The monsoon climate implies that precipitation amount peaks in summer as does the occurrence of heavy rainfall events. While the trend test has revealed a significant trend in summer rainfall, no statistically significant change was observed in heavy rain intensity. The 1-day, 3-day and 7-day extremes show only a minor increase from a basin-wide point of view. However, a significant positive trend was found for the number of rainstorm days (daily rainfall ≥50 mm). The increase of rainstorm frequency, rather than intensity, on the middle and lower reaches contributes most to the positive trend in summer precipitation in the Yangtze.     

Inference about trends in global temperature data

Interpretation of the effects of increasing atmospheric carbon dioxide on temperature is made more difficult by the fact that it is unclear whether sufficient global warming has taken place to allow a statistically significant finding of any upward trend in the temperature series. We add to the few existing statistical results by reporting tests for both deterministic and stochastic non-stationarity (trends) in time series of global average temperature. We conclude that the statistical evidence is sufficient to reject the hypothesis of a stochastic trend; however, there is evidence of a trend which could be approximated by a deterministic linear model.The authors are grateful to the SSHRC (Green) and FCAR (Galbraith) for financial support under grants 10-89-0205 and NC-0047.     

On rising temperature trends of Karachi in Pakistan

Karachi is the largest city of Pakistan. The temperature change in Karachi is studied in this research by analyzing the time series data of mean maximum temperature (MMxT), mean minimum temperature (MMiT) and mean annual temperature (MAT) from 1947 to 2005 (59 years). Data is analyzed in three parts by running linear regression and by taking anomalies of all time periods: (a) whole period from 1947–2005; (b) phase one 1947–1975 and (c) phase two 1976–2005. During 1947 to 2005 MMxT has increased about 4.6°C, MMiT has no change and MAT has increased 2.25°C. During 1947–1975, MMxT increased 1.9°C, in this period there is − 1.3°C decrease in MMiT and MAT has raised upto 0.3°C. During 1976–2005, the MMxT, MMiT and MAT increased 2.7°C, 1.2°C and 1.95°C, respectively. The analysis shows significantly the role of extreme vulnerability of MMxT in rising the temperature of Karachi than the MMiT.     

Observed trends in diurnal temperature range over Nigeria

本文基于站点观测及再分析资料,考察了1979–2013年期间尼日利亚不同地区温度日较差(DTR)的变化趋势及其可能原因。结果表明,尼日利亚北部萨赫勒地区(NSR)日最低温的增温趋势显著大于日最高温增加的趋势,导致该区域DTR呈显著下降趋势(–0.34°C/10年);而在南部几内亚湾地区(NGC),区域平均日最高温度增加趋势略大于最低温度的增加趋势,导致该区域平均DTR呈微弱上升趋势(0.01°C/10年)。NSR区域显著的DTR下降趋势与该地区降水量呈长期增加趋势密切相关,而NGC区域DTR的增加趋势则可归因于该地区云量存在的长期减少趋势。     

陕西省风蚀气候侵蚀力时空演变特征

利用陕西省94个气象站1981-2020年气象观测资料计算了全省风蚀气候因子指数,采用气候趋势分析、空间插值、敏感性分析等方法,分析了陕西省风蚀气候侵蚀力演变特征及其对风速变化的响应.结果表明:(1)陕西省1981-2020年平均风蚀气候侵蚀力为3.18,侵蚀力较小,年际变化显著,但变化趋势不明显;风蚀气候侵蚀力在20...     

Spatial and temporal trends of extreme temperature and precipitation in the Daqing River Basin,North China

Theoretical and Applied Climatology - According to the daily maximum and minimum temperature and the precipitation at 40 meteorological stations in the Daqing River Basin of China during...