1973—2012年4—10月呼伦贝尔市地面温度时空分布特征

利用呼伦贝尔市1973—2012年4—10月地面0cm温度观测资料,对在全球变暖环境下地面温度的时空分布特征进行分析。分析表明：呼伦贝尔市地面温度呈现随纬度和高度递减的分布方式,各台站地面温度呈现显著上升趋势,平均年倾向率为0.82℃/10a,夏季变率明显高于秋冬季,秋季各台站间的变率差距较大。大多数台站2007年为地面温度显著偏高的异常年,突变大多发生在20世纪90年代后期至21世纪10年代初期,重现期百年一遇在40.9-34.8℃之间变化,20a一遇在33.7~39.4℃之间,新巴尔虎左旗较高,根河较低。     

商丘近40年气温变化特征

统计分析了商丘1961—2000年年平均气温，月平均气温，年平均最低、最高气温和月平均最低、最高气温变化，结果表明：年平均气温呈上升趋势，年平均最低气温也呈上升趋势，而年平均最高气温却呈下降趋势，这种日夜气温变化的不对称性，使日较差呈变小趋势；商丘偏暖年集中在20世纪60年代初期和90年代，偏冷期集中在20世纪60年代末期到80年代；20世纪90年代商丘年平均气温增高是一突变现象。     

气候变暖背景下我国南方旱涝灾害时空格局变化

我国南方地区各季节降水异常主要包含三种优势模态：长江及其以南地区降水呈整体偏多或偏少的一致型,长江中下游流域与华南呈反相变化的南北反相型以及东南与西南呈反相变化的东西反相型。其中一致型是南方地区各季节降水变率的第一优势模态。总体而言,在1961—2013年南方地区平均降水存在明显的年代际和长期趋势变化。其中,夏季和冬季南方区域平均降水具有相似的年代际变化特征,而秋季降水的年代际演变几乎与上述两个季节的相反。不过,在近30年南方各季降水量发生年代际转折的时间不尽相同：春季和秋季降水分别在21世纪初期和20世纪80年代中后期之后进入干位相,冬季和夏季降水则分别在80年代中期和90年代初期之后进入湿位相。自21世纪初期以来,南方夏季和冬季降水逐渐转入中性位相。此外,南方春季和秋季降水均呈减少趋势;而夏季和冬季则相反,均呈增多趋势。对于西南地区,除了春季外,其他三个季节的降水均呈减少趋势,出现了季节连旱的特征,尤其是秋旱最为严重。不过,不管是季节降水量还是旱/涝日数,在我国南方大部分地区其线性变化趋势并不十分显著,这与南方降水年代际分量对降水变率存在较大贡献相关。分析还发现,我国南方区域洪涝受灾面积具有比较明显的年代际变化,而干旱受灾面积则没有明显的年代际变化特征,近十多年来西南地区干旱和洪涝受灾出现了交替互现的特点。     

近50年韩城无霜期气候变化特征分析

利用韩城1970—2019年初、终霜日及无霜期资料,运用统计方法对韩城初、终霜日及无霜期气候特征及变化趋势进行分析。结果显示:韩城近50 a平均初霜日为10月29日,呈推迟趋势,线性倾向率为16 d/10 a;平均终霜日为3月28日,呈提前趋势,线性倾向率为-57 d/10 a;无霜期为2135 d,呈增长趋势,线性倾向率为67 d/10 a,其变化促使热量资源稳定上升,将有利于农业生产,有助于提高花椒农产品产量和品质。韩城初霜日推迟不明显,2018年发生突变;终霜日提前趋势十分显著,2010年发生突变,无霜期增长趋势十分显著,并在2013年发生突变。韩城初霜日存在2 a和5 a左右的振荡周期,在20世纪70年代中期到80年代初期、90年代中期表现为明显的2 a振荡周期;终霜日存在2～4 a和6 a左右振荡周期,在70年代中期到80年代初期表现为明显的3 a振荡周期;无霜期在70年代中期到80年代初期、90年代末期到2000年初期、2007—2014年表现为明显的2～4 a振荡周期。韩城初霜日和无霜期年际变化基本一致,终霜日呈相反趋势。对韩城初（终）霜日早晚、无霜期长短年份进行划分,终霜日提前或推迟对无霜期的增长或缩短起主要作用,初霜日推迟或提前对无霜期的增长或缩短所起的作用不明显。     

和田河流域气候变化特征分析

利用和田河流域和田市气象站1961-2000年的气温和降水量资料，分析了和田河流域气温和降水量的年代际以及线性趋势变化。分析表明和田河流域气候演变存在非常明显的年际和年代际变化，近40年和田市年平均气温呈上升趋势，倾向率为0．26℃／10a，降水量总体呈增多趋势，其倾向率为1．56mm／10a。20世纪90年代增温十分明显，1999年是近40年来和田河流域最暖的一年。     

基于标准化降水指数的近51a山东临沂市旱涝时空特征

基于1961—2011年临沂市10个气象观测站的逐月降水数据,采用标准化降水指数（SPI）,分析了临沂市旱涝时空分布特征。结果表明：临沂市旱涝变化具有阶段性特征,1960年代初中期和1970年代初中期,雨涝频繁;1960年代中后期和1970年代中后期及整个1980年代,干旱频繁;1990年代到21世纪初早期旱涝交替发生,2003年以后以雨涝为主。冬春季干旱呈弱的减轻趋势,秋旱呈弱加剧趋势,夏季旱涝变化趋势不明显。北部山区、西部丘陵、南部平原的旱涝变化总体上具有相对一致的趋势,但在1960年代中期、1980年代中期、21世纪初早期西部丘陵的旱涝变化幅度较其他2个区域要大。全市旱涝变率在21世纪初早期最大,1970年代中后期最小,3个区域的变率总体上表现出与全市大致相同的趋势,2004年以后南部平原旱涝变率持续增大。     

21世纪天山南坡台兰河流域径流变化情景预估

基于台兰水文站2003—2005年观测的水文气象数据,通过参数率定和验证获得了适用于台兰河流域的HBV水文模型优化参数。应用RegCM3气候模式在IPCC SRES A1B情景下的预估数据,经Delta降尺度方法生成流域未来气候数据,并结合流域冰川退缩情景预估台兰河流域径流在21世纪中期(2041—2060年)和末期(2081—2100年)可能发生的变化。结果表明:在21世纪中期和末期,台兰河流域气温将显著上升,而降水变化不大;21世纪中期冰川3种可能退缩比例为15%、20%和25%,末期分别为20%、30%和40%;无论冰川处于哪一种退缩情景,21世纪径流较基准期(1981—2000年)都呈增加趋势,中期和末期最小增幅将分别为17.3%和18.6%;最大增幅可达45.9%和66.0%;耦合RegCM3气候模式预估增幅为28.9%和41.5%;台兰河流域未来径流年内分布与基准期大体相同,但又呈现出一定的差异性,具体表现为,在21世纪中期5月份径流增加很快,径流峰值出现在7月份,而到21世纪末期径流峰值出现在8月份。     

河西走廊强和特强沙尘暴变化趋势的初步研究

分析了河西走廊1955—2000年强和特强沙尘暴的气候变化。研究表明，河西走廊强和特强沙尘暴自1955年以来主要呈下降趋势；但是从20世纪90年代末期起，有增多的趋势。20世纪50年代和70年代偏多，60年代正常，80年代偏少，90年代最少。强和特强沙尘暴的突变年份出现在60年代后期和1980年前后。     

东莞市1980—2010年浅层地温的变化特征

根据1980—2010年东莞市国家气象观测站0～20 cm各层逐月平均地温,采用线性趋势法分析了东莞市近30年浅层地温变化特征。结果表明:年平均地温升温率在0.001～0.105℃/年,夏季最大,春季最小;20世纪80年代前期变化较为平稳,80年代后期至90年代中期处于低温期,2000年之后有明显的下降趋势。地面最高温度呈逐年递减,递减率为0.344℃/年,地面最低温度呈逐年递增,递增率为0.036℃/年,地面最高温度的递减趋势远大于最低温度的递增趋势,地面气温差距也明显减小。     

毕节气温与降水变化特征及趋势预报

本文通过对我市1951～1990年共40年气温、降水资料的分析得出：近40年来我市年平均气温呈波动式微变冷的趋势，其中春季变冷明显，夏、秋、冬三季则呈波动式略变暖的趋势。年降水量显著减少，丰水期主要出现在50年代，枯水期主要出现在80年代。春、秋两季降水量的变化以60年代末期为分水岭，50～60年代末期呈增多趋势，60年代末期至今则呈明显减少趋势。夏季降水量40年来呈明显减少的趋势，主要丰水期和枯水期与年降水量分布一致。冬季降水量则有大约20年一个波动的周期。     

广西近百年气温和降水序列的多时间尺度分析

对广西近百年平均气温及降水量变化进行了多时间尺度的层次结构研究,并与Nino3区的海温距平进行奇异交叉谱分析。结果表明：平均气温有较强上升趋势并伴有明显的准两年周期振荡;降水则呈下降趋势,主要周期为32 a左右及准两年振荡。1884至1910年代初,广西处于干冷期;1910年代初至1930年前后,处于湿冷期;1930年前后至1950年代后期,处于湿暖期;1950年代后期至1990年代前期,处于干暖期。ENSO事件3~7 a的周期对广西平均气温及降水影响显著,赤道太平洋海温变化对广西气温的影响主要表现在年代际变化上,对降水的影响主要体现在年际变化上。     

近百年上海气候变暖过程的再认识——平均温度与最低、最高温度的对比

该文就近113年（1880～1992年）上海逐月平均最低、最高和平均气温3个序列进行了深入细致的诊断分析。结果发现:最低气温和平均气温近百年虽都呈显著上升趋势,但前者比后者更为持续稳定,其增温率更高于后者。这一特点表明,最低气温对于监测温度效应加剧可能更为敏感;最高气温自20世纪40年代中后期却出现了明显的趋势转折。近百年上海气候变暖主要表现为三次突然增暖,其中10年代的增暖仅限于白天,30年代则以白天增暖较多,80年代以来则主要发生于夜间。这些事实将有助于进一步对上海及中国区域或全球变暖的再认识。     

Surface temperature variation over Zimbabwe between 1897 and 1993

Summary The surface temperature variation over Zimbabwe, and, Harare and Bulawayo between 1933 and 1993, and, 1897 and 1993 respectively, is investigated. For the national average two significant warm phases are identified, with a net warming of +0.3 to +0.5°C since 1933. Warming occurs in maximum temperature, whereas the mean national temperature cools. The effect of the rainfall pattern on temperature is also investigated. If warming phases coincide with drought years and the warming is confined to the rainy months only, then reduced cloudiness could be an important factor in explaining some of the warming. The first warm phase occurs during the mid-1930s to late 1940 and the second major warm phase occurred from the early 1980s onwards. For Harare, with temperature records starting before 1900, a major warming phase occurred between about 1910 and late 1920. The effect of drought on the national temperature record is evident through a strong negative association between maximum temperature anomalies and rainfall anomalies. A number of possible causes of the observed changes are discussed. The effects of urbanisation and industrialisation on temperature trends over Harare and Bulawayo are quite conspicuous. The question that remains difficult to answer is whether the observed warming trend is a result of inherent climate variability, enhanced greenhouse effect or a combination of many factors.With 17 Figures     

温室气体、海表面温度、太阳常数及火山活动对中国地表气温影响之初探

利用全球大气环流模式CAM3.1,对近百年温室气体浓度、全球海表面温度、太阳常数的变化以及火山活动对我国地表气温所产生的影响进行了研究。全球海表面温度的升高及温室气体浓度的增加是导致中国年平均地表气温升高的部分因素。近百年我国年平均地表气温主要经历了两次年代际振荡并逐渐增温。第一次振荡的冷期为1910年代,随后变暖,1940年代达暖峰期。第二次振荡冷期发生于1950~1960年代,随后变暖,暖峰期发生在1990年代。太阳常数和全球海表面温度的两次振荡是造成这两次振荡主要因素,气温、太阳常数和全球海表面温度均发生了准60年周期的年代际振荡,气温振荡的位相落后于太阳常数和全球海表面温度的位相。20世纪20年代以前及60年代以后火山活动的活跃是导致1910年代和1960~1980年代出现冷期的原因之一。     

A 150-year reconstructed summer Asian�CPacific Oscillation index and its association with precipitation over eastern China

Reconstructing the long-term series of the East Asian summer monsoon (EASM) indices may help understand long-term variability of EASM and its associations with precipitation. In this study, the summer middle?Cupper tropospheric temperature over the Asian?CNorth Pacific sector is reconstructed from sea level pressure during the past 150?years, and then an atmospheric thermal contrast between Asia and the North Pacific, called the Asian?CPacific Oscillation (APO) index, is calculated from the reconstructed temperature. The results show that the APO phenomenon may occur in the reconstructed temperature fields, and its index has a significant positive/negative correlation with SST over the extratropical North Pacific/the tropical central?Ceastern Pacific in the past 150?years. The reconstructed summer APO index shows inter-decadal variability, with a positive phase in the 1870?C1890s, the 1920s, and the 1940?C1970s, indicating a stronger thermal contrast between Asia and the North Pacific, and with a negative phase in the 1860s, the 1900?C1910s, and the 1980?C1990s, indicating a weaker thermal contrast. Corresponding to a higher APO index in earlier decades of the twentieth century, there are more rainfall to the south of the Yangtze River and over North China and less rainfall over the Huaihe River valley. In the recent decades, however, more- and less-rain belts shifted southwards when the APO index is higher. During 1850?C1900, the reconstructed APO index also showed a significant positive correlation with precipitation in some regions of North China.     

The 20th century cooling trend over the southeastern United States

Portions of the southern and southeastern United States, primarily Mississippi, Alabama, and Georgia, have experienced century-long (1895–2007) downward air temperature trends that occur in all seasons. Superimposed on them are shifts in mean temperatures on decadal scales characterized by alternating warm (1930s–1940s, 1990s) and cold (1900s; 1960s–1970s) regimes. Regional atmospheric circulation and SST teleconnection indices, station-based cloud cover and soil moisture (Palmer drought severity index) data are used in stepwise multiple linear regression models. These models identify predictors linked to observed winter, summer, and annual Southeastern air temperature variability, the observed variance (r²) they explain, and the resulting prediction and residual time series. Long-term variations and trends in tropical Pacific sea temperatures, cloud cover, soil moisture and the North Atlantic and Arctic oscillations account for much of the air temperature downtrends. Soil moisture and cloud cover are the primary predictors of 59.6 % of the observed summer temperature variance. While the teleconnections, cloud cover and moisture data account for some of the annual and summer Southeastern cooling trend, large significant downward trending residuals remain in winter and summer. Comparison is made to the northeastern United States where large twentieth century upward air temperature trends are driven by cloud cover increases and Atlantic Multidecadal Oscillation (AMO) variability. Differences between the Northeastern warming and the Southeastern cooling trends in summer are attributable in part to the differing roles of cloud cover, soil moisture, the Arctic Oscillation and the AMO on air temperatures of the 2 regions.     

Climatic regime shift and decadal anomalous events in China

Climatic time series from historical documents and instrumental records from China showed temporal and regional patterns in the last two to three centuries, including two multidecadal oscillations at quasi-20-year and quasi-70-year timescales revealed by signal analysis from wavelet transform. Climatic anomalous events on the decadal timescale were identified based on the two oscillations when their positive (or negative) phases coincide with each other to amplify amplitude. The coldest event occurred in the decade of 1965–1975 in eastern China, while the periods of 1920–1930, 1940–1950, and 1988–2000 appeared to be warmer in most parts of China. For the precipitation series in northern China, the dry anomalous event was found in the late 1920s, while the wet anomalous event occurred in the 1950s. A severe drought in 1927–1929 in northern China coincided with the anomalous warm and dry decade, caused large-scale famine in nine provinces over northern China. Climatic anomalous events with a warm-dry or cold-wet association in the physical climate system would potentially cause severe negative impacts on natural ecosystem in the key vulnerable region over northern China. The spatial pattern of summer rainfall anomalies in the eastern China monsoon region showed an opposite variations in phase between the Yellow River Valley (North China) and the mid-low Yangtze River Valley as well as accompanied the shift of the northernmost monsoon boundary. Climatic regime shifts for different time points in the last 200 years were identified. In North China, transitions from dry to wet periods occurred around 1800, 1875, and 1940 while the transitions from wet to dry periods appeared around 1840, 1910, and the late 1970s. The reversal transition in these time points can also be found in the lower Yangtze River. Climatic regime shifts in China were linked to the interaction of mid- and low latitude atmospheric circulations (the westerly flow and the monsoon flow) when they cross the Tibetan Plateau in East Asia.     

Unprecedented Warming Revealed from Multi-proxy Reconstruction of Temperature in Southern China for the Past 160 Years

Using the southern limit of snowfall recorded in Chinese documents, chronologies of tree-ring width, and tree-ring stable oxygen isotope(δ~(18)O), the annual temperature anomaly in southern China during 1850–2009 is reconstructed using the method of signal decomposition and synthesis. The results show that the linear trend was 0.47℃(100 yr)~(-1)over 1871–2009,and the two most rapid warming intervals occurred in 1877–1938 and 1968–2007, at rates of 0.125℃(10 yr)~(-1)and 0.258℃(10 yr)~(-1), respectively. The decadal variation shows that the temperature in the moderate warm interval of the 1910s–1930s was notably lower than that of the 1980s–2000s, which suggests that the warming since the 1980s was unprecedented for the past 160 years, though a warming hiatus existed in the 2000s. Additionally, there was a rapid cooling starting from the 1860s,followed by a cold interval until the early 1890s, with the coldest years in 1892 and 1893. A slight temperature decline was also found from the 1940s to the late 1960s. This study provides an independent case to validate the global warming for the past 160 years and its hiatus recently, because the proxy data are not affected by urbanization.     

1880—2010年中国东部夏季降水年代际变化特征

利用1880—2010年中国东部66站夏季降水数据,开展夏季长序列降水的年代际变化特征研究。结果表明,中国东部夏季降水年代际变化特征显著,华北、江淮和华南地区存在明显的差异。经验正交分解结果表明,偶极型("-+"和"+-")和三极型("+-+"和"-+-")分布是中国东部夏季的两种主要降水模态。夏季500 h Pa高度场年代际分量与同期太平洋SST典型相关分析(BP-CCA)得出,太平洋年代际振荡(PDO,Pacific Decadal Oscillation)正位相可以激发出负的PJ型遥相关波列,导致长江中下游地区降水偏多,华北降水偏少;反之亦然。同时,通过滑动相关分析发现,中国东部不同区域的夏季降水对PDO不同位相的响应特征存在差异。     

CHARACTERIZATION AND CAUSAL ANALYSIS OF TEMPORAL AND SPATIAL VARIATION IN DRY-WET CONDITIONS IN AUTUMN IN SOUTHWEST CHINA

Based on the daily precipitation and temperature data of 97 stations in Southwest China(SW China) from1960 to 2009, a dry-wet index is calculated. The spatiotemporal variation characteristics of dry-wet conditions,precipitation and temperature are studied. Then the abnormal atmospheric circulation characteristics are discussed using reanalysis data. The results show that SW China has exhibited an overall trend of autumnal drought since the late1980 s, and this drought trend became more significant early in the 2000 s, especially in the eastern SW China. Autumnal dry-wet variation in southwestern China showed two major modes: consistent change across the entire region and opposing changes in the eastern and western regions. The spatial distribution of dry-wet anomalies was more significantly affected by precipitation, while temporal variation in dry-wet conditions was more strongly influenced by temperature. The former mode is affected by the anomalies of the precedent SST near the Western Pacific Warm Pool,the Western Pacific Subtropical High, the East Asian Trough and the South Trough. The latter mode is related to the wind anomalies in the eastern SW China and the vertical movement in the western and eastern SW China. These are the main influencing factors for the autumn dry-wet variation in SW China, which are of great significance to the prediction of drought.