The Use of Indices to Identify Changes in Climatic Extremes

Changes in the frequencies of extremes are investigated by a variety of methods using daily temperature data from the British Isles, and monthly 5° latitude × 5° longitude grid-box temperatures over the land and marine regions of the world. The 225 year long daily Central England Temperature record shows no significant increase in very warm days in recent years but there is a marked decrease in the frequency of very cold days. Thus the rise in temperature in the last two decades is principally associated with a reduction in very cold days. Temperatures on days with particular wind circulation or pressure pattern types over the British Isles show multidecadal variations. Analyses using monthly gridded temperature data around the world since 1951 indicate that the recent rise in global surface temperatures is accompanied both by reductions in the areas affected by extremely cool temperatures and by increases in the areas with extremely warm temperatures.     

Extremes of Daily Rainfall in West Central Florida

Annual maxima of daily rainfall data dating from 1901 to 2003 are modeled for fourteen locations in West Central Florida. The generalized extreme value (GEV) distribution is fitted to data from each location. The location parameter of the GEV is formulated as a function of time to adequately describe the extremes of rainfall and to predict their future behavior. We find evidence of non-stationarity in the form of trends for eight of the fourteen locations considered. We quantify the change in extreme rainfall for each location and provide return levels for the years 2010, 2020, 2050 and 2100. We also derive estimates of return levels for daily rainfall and provide a classification of the fourteen locations based on the degree of severity of these estimates. This paper provides the first application of extreme value distributions to rainfall data specifically from Florida.     

The Crisis of Wine Production in Late Sixteenth-Century Central Europe: Climatic Causes and Economic Consequences

From the mid-1580s wine production all over Central Europe dropped to a low level that was maintained beyond the turn of the century. This is concluded on the basis of four series of wine production from Lower Austria, Western Hungary, Württemberg, and the region surrounding the lake of Zürich (Switzerland) for the period 1550--1630. This long sequence of crop failures is related to a temperature decline in all seasons, particularly in winter, affecting Europe north of the Alps. The economic, social and political consequences of this climatic "gearshift" are investigated from the example of Lower Austria. It is shown that it had far-reaching effects for major social groups depending on the wine economy and the revenues of the Habsburg crown.     

3-hourly quantitative precipitation estimation over Central and Northern Europe from rain gauge and radar data

Continental-scale 3-hourly precipitation fields have been analysed from operational CERAD (Central European Radar) and BALTRAD (Baltic Radar) networks and adjusted with daily precipitation measurements from about 10,000 synoptic and climate stations. Here we focus on the application of CERAD and BALTRAD for quantitative precipitation estimation (QPE) that is the choice of quality control methods, the impact of input radar data quality on the analysis results and the analysis algorithm. The quality of the radar derived precipitation fields has been estimated by comparison with ground truth fields at the spatio-temporal scale of the ELDAS (European Land Data Assimilation System) project grid (0.2°/daily). Additionally, statistics on the availability of CERAD and BALTRAD data for the entire ELDAS period from Oct. 1999 to Dec. 2000 have been compiled. The final ELDAS precipitation product covers the whole of Europe and is available in GRIB format from the ECMWF MARS archive.     

影响中国及关键经济区热带气旋降水的气候趋势及极端性特征

本文利用中国气象局上海台风研究所整编的《热带气旋年鉴》(1951~2010年)最佳路径资料,分析影响我国和关键经济区热带气旋(TC)降水量、降水强度以及不同等级降水TC频数的气候变化趋势,研究结果表明,影响全国的TC总降水量的年际变化幅度大,年际差异显著。长江三角洲、珠江三角洲地区影响TC过程雨量年极值自1970年代开始缓慢上升,表明近年来TC引起的极端性降水存在增加的可能。全国范围内自1970年代开始,过程雨量大于250 mm的TC频数也在增加,但长江三角洲、珠江三角洲地区发生极端性降水的TC频数并没有明显的增长。TC造成的24小时降水极值的气候变化趋势不明显,但是1980年代全国范围内的24小时降水极值存在跃变。长江三角洲、珠江三角洲地区日降水极值超过250 mm的TC频数自1980年代开始有缓慢增加趋势。全国范围、长江三角洲及珠江三角洲内TC小时降雨量年极值呈现振荡的周期变化,而在年代际上没有明显的变化趋势。     

近40年我国极端温度变化趋势和季节特征

利用1961—2000年我国194个测站逐日最高温度和最低温度器测资料,结合具有实际意义的季节极端温度指数,分析了我国近40年极端温度事件的年变化趋势和季节特征。对年极端气候指数的研究表明：绝对阈值定义的冷暖指数由于无法考虑南北气候差异,其结果不理想。百分比阈值所得的冷暖指数中,冷日指数和暖日指数具有不对称性,冷夜指数和暖夜指数具有较强的对称性。对季节极端温度指数研究表明：冬季极端冷指数变化趋势最为明显,夏季极端暖指数的变化趋势次之,春、秋两季极端冷指数的变化趋势不明显;年和季节尺度的极端冷暖指数均反映出增暖趋势。     

北方强降水的气候特征

本文利用最近30—40年的资料,分析了北方强降水的气候特征。文中指出：北方暴雨日数明显少于南方,但强度大。我国大陆上的不同历时降水极值均出现在北方;降水时间集中在盛夏;最大一日降水量的强度对年降水量多寡有显著影响,且最大一日降水量的年际变差明显;北方的强降水常伴有强烈雷暴活动、历时短、降水覆盖面积小。     

Study of changes in the regime of atmospheric precipitation in the Central Northern Caucasus

Results of statistical analysis of changes in the precipitation regime in the steppe and foothill climatic zones of the Central Northern Caucasus from the data of five weather stations for 1955–2004 on precipitation amount, its diurnal maximum, number of days with precipitation amount of 5 mm or more in different seasons of the year are considered.     

Climatic changes in Europe and the near east in the second millenium BC

The old pollen-analysis based picture of the climatic epoch Sub-Boreal in Europe, 3000 or 2500 to 800 BC, which embraces the second millenium, is in need of a thorough revision in light of the relatively recent researches in the Alps. The researches of concern are glacial-variation studies, mainly of the 1970s, and tree-ring density analyses of the subalpine zone of the late 1970s, reported in 1982.The results indicate that, after a warm and dry epoch ending about 1800 or 1700, a cold period set in in the Alps, lasting to about 1470 BC. (All dates below are BC unless otherwise stated; datings determined by radiocarbon analyses are subject to a maximum possible error of + or – 100 yrs.) This cold phase was followed by an approximately 70 yrs long warm phase. But the most pronounced change occurred about 1400, when rather abruptly a second cold phase was ushered in, continuing until about 1230. This second cold phase is often referred to under the name Löbben Phase, which is considered to have been the coldest and longest-sustained cold period of the past 8000 yrs, colder than the recent Little Ice Age of the CE (= Christian Era). Its temperature level is estimated (by G. Patzelt) to have been 0.7 to 1 °C colder than the present level in the Alps. The rise of level of the Swiss lakes, including Lake Constance testify that the Löbben Phase was associated with an enhanced rainfall.In the 13th and the beginning of the 12th centuries major and violent migrations took place from central Europe, including Hungary, and the southeast of the continent toward the south and the southeast, including the Near East as far as the Nile Delta. In order to elucidate if the cold-wet phases of the Alps were cold-wet in central Europe, we have carried out air temperature correlations between an Alpine station Säntis (2500 m MSL) and Budapest, for 1921–70. The correlation coefficient is 0.70 for the annual temperatures and 0.82 for July–September of the same years. Since glaciers grow in cold-wet summers, the high correlation for the summer months means that central Europe must have been cold in most of the cold summers of the Alps. But, cold, and especially cold-wet summers are detrimental to agriculture. Presumably, partial or total crop failures must have been relatively frequent in central Europe forcing the people to take to migration. Archeological evidence from Hungary indicates that there were hardly any settlements left, compared with the previous centuries.Finally, we quote evidence to show that some of the groups of the Sea Peoples, who tried to invade the Nile Delta about 1190, were of European origin. They abandoned their homeland, presumably because of a turn of the climate to cooler and wetter conditions. It is noted that our interpretation of the causes of migrations of the 13th century and beginning of the 12th, is different from that put forward by Weiss (1982).This paper formed the substance of an invited opening address to theInternational Workshop on Regional Implications of Future Climatic Change, held at the Weizmann Institute of Science, Rehovot, Israel, 28 April–2 May 1991.Visiting with the Department of Meteorology, University of Copenhagen, Copenhagen, Denmark, since 1986.     

Climatic controls on Holocene lake-level changes in Europe

Sensitivity experiments with a simple water-balance model were used to constrain the possible climatic causes of distinct Holocene patterns of lake-level variation in different regions of Europe. Lakes in S Sweden were low at 9 ka, high around 6.5 ka, low again around 4 ka and are high now. Lakes in Estonia show similar but weaker trends. Lakes in S France were highest around 9 ka, lowest around 4 ka, intermediate now. Lakes in Greece were also high around 9 ka but continued rising until 7.5 ka, then fell gradually from 5 ka with a brief high phase around 3 ka, and are low now. The model was forced with insolation anomalies deduced from orbital variations, temperature anomalies inferred from the pollen record and cloudiness anomalies derived from changes in the position of the subtropical anticyclone (inferred from reconstructed changes in the equator-to-pole temperature gradient), in order to evaluate the effects of resultant evaporation changes on catchment water balance. The resulting simulated changes in runoff (precipitation minus actual evapotranspiration) were slight, and frequently opposite to the observed trends. Larger changes in precipitation are plausible and are required to explain the data. The required precipitation increase in N Europe from 9 ka (low) to 6 ka (high) is suggested by GCM experiments to have been a consequence of interacting insolation and residual ice-sheet effects on the atmospheric circulation over the North Atlantic. The explanation of other observed changes, including the drying trend during the Holocene in S Europe, has not been provided by GCM experiments to date. Explanations may lie in changes in mesoscale circulation, sea-surface temperature patterns and the coupling between these phenomena that may not follow orbital changes in any simple way. Correspondence to: SP Harrison     

海温气候振动和北半球对流层高度场变化

近40年赤道太平洋和北太平洋月平均海温距平场分布存在着短期气候振动,分析表明,它对大气环流有一定的影响。在海温气候振动的前期位相时期,对流层平均高度有降低趋势,相反在海温气候振动的后期位相时期,对流层平均高度为增高趋势。这种相关关系高层比低层要好,低纬度较中高纬度稳定,夏季较冬季明显。     

北疆复播地膜玉米的气候适应性初探

北疆乌兰乌苏的地膜玉米分期复播田间试验表明:随着复播日期的推迟,收获籽粒的百粒重和单穗籽粒干重呈下降趋势。7月5日前播种,90d以上的生长期,≥10℃活动积温2000℃·d,才能保证复播地膜玉米承单3号的正常成熟。     

山西省北(中)部作物冷害的初步研究

生产实践表明，山西省北（中）部存在着程度不同的作物冷害，严重冷害年常造成作物产量大幅度下降，本文初步研究了该区冷害发生的时段，指标，类型，分析了冷害的时空分布，有针对性的提出了可操作的防御与减轻冷害的措施建议。     

The Changing Incidence of Extremes in Worldwide and Central England Temperatures to the End of the Twentieth Century

Annual and seasonal gridded ocean surface temperature anomalies show an increase in warm extremes and a decrease in cold extremes since the late 19th century attributable entirely to the overall warming trend. Over land, however, a reduction in the total incidence of extremes may reflect improved instrumental exposures. Our estimates of extremes are made by deriving percentiles from fits of anomalies on 5° latitude ×5° longitude resolution to modified 2-parameter gamma distributions. A non-parametric method is used to check the validity of the results. Fields of percentiles created using this technique can be used to map the distribution of unusual temperature anomalies across the globe on any time scale from a month to about a decade, from 1870 onwards. We apply a similar technique to assess changes in the incidence of extreme daily Central England temperature anomalies. The incidence of these extremes, relative to individual monthly average temperatures, has declined.     

桂中春季短期气候预测的模糊评判

应用模糊综合评判的方法,建立了桂中春季低温阴雨总日数与前期５个预报因子在不同的预报等级下各个因子区间的隶属度矩阵,以此作为模糊变换矩阵Ｒ～及因子权重Ａ～的备选元素,然后,根据不同年份的因子值来构造Ｒ～和Ａ～,由算子Ｍ（·,０）作出预报等级的归属评判,其准确率要比目前气象部门所用的预报方法高１５－２０％。     

中国北方冬小麦蚜虫气候风险评估

基于1958—2018年中国北方冬小麦主产区8个主产省（市）小麦蚜虫发生面积、防治面积和小麦播种面积、产量损失、561个气象站点逐日气象资料和典型农业气象站小麦发育期资料,采用相关分析、主成分分析和回归分析等方法,构建华北、黄淮及苏皖地区小麦蚜虫分区域的气候致灾指数。以小麦蚜虫年代际气候致灾指数所划分不同致灾等级发生频次作为小麦蚜虫气候危险性指标,采用小麦蚜虫发生面积率作为脆弱性指标,防治面积与发生面积比值作为防灾减灾能力指标,综合评估小麦蚜虫气候风险趋势。结果表明：北方冬小麦主产区小麦蚜虫气候危险性呈增加态势,年代际差异明显;小麦蚜虫发生脆弱性随年代变化也呈逐步加重态势;小麦蚜虫防灾减灾能力总体呈逐步增强趋势,20世纪90年代提升显著;90年代起小麦蚜虫气候风险逐步加重,高风险范围逐渐扩大,华北、黄淮分别于21世纪初、2011—2018年风险等级达最高;小麦蚜虫气候风险高的区域主要分布在北京、天津、河北中南部大部、山东北部部分地区,较高区域分布在山东大部、河南北部等地。     

北疆冰雪运动气候适宜性及其变化特征

基于北疆43站的降雪量、日平均气温、日最高气温以及日平均风速等资料,应用冰雪运动气候适宜性指数(ISCI),对1961—2017年冬春季北疆的冰雪运动适宜性及其变化特征进行评估,结果如下：(1)北疆大部分站点都适宜开展冰雪运动,阿勒泰等地最为适宜,但伊犁河谷大部分站点、阿拉山口与达坂城等地适宜程度相对较低。(2)冰雪运动气候适宜程度与降雪量并非线性关系,北疆冬春季区域平均降雪量越大,很适宜与不适宜开展冰雪运动的站点都越多。海拔在1200 m以上的站点均适宜开展冰雪运动。(3) ISCI指数的年际差异明显,区域平均ISCI指数随时间推进而减小,但不同站点的ISCI指数线性变化趋势有升有降。1998—2017年期间,北疆适宜冰雪运动的站点较之前大范围减少。(4)阿勒泰地区各站在所有时间阶段中均适宜开展冰雪运动,尤其是阿勒泰北部,冰雪运动气候适宜程度呈阶段性增大,而伊犁河谷大部分站点的冰雪运动适宜程度整体呈阶段性减小。     

淮阴地区旱涝气候分析

作者以淮阴市历年的雨涝，干旱实况为依据，参考农业，水利部门统计的受灾面积，防洪排涝能力，农作物不同生育期的需水量等因素，按季节分析雨涝，干旱灾害与雨量关系，确定年季不同级别的旱涝指标，其分析结论是４０多年来旱涝灾年发生的频数超过正常年，且涝灾多于旱灾，重于旱灾，但秋旱多于秋涝。