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.     

Geomorphic Variations of Debris Flows and Recent Climatic Change in the French Alps

Much work has been done to show that there is a relationship between the triggering of debris flows and the recorded increase in temperatures or in the number of intense rainy events over the last few decades. The question addressed in this paper is that of the impact of these climate changes on the dynamics of debris flows since the 1950s. 319 debris flows in the Dévoluy and Ecrins massifs located in the French Alps, the triggering of which is independent of the current glacial retreat, have been analysed. In the Dévoluy a reduction in the number of debris flows was observed in the periods 1950–1975 and 1975–2000. In the Massif des Ecrins, we have observed a shift of the triggering debris flow zone toward higher elevations and a lack of significant variation in the number of debris flows. But in the Massif des Ecrins this global result masks two different trends depending on elevation. At low altitude (<2200 m) the number of debris flows and the frequency of debris flows less than 400 m in length have decreased significantly since the 1980s whereas no significant variation was observed at high altitude (>2200 m). At the same time, we have observed a significant increase in the annual and seasonal temperatures for these 20 last years combined with a significant reduction in the number of freezing days. A significant increase in summer rains higher than 30 mm/d has also been observed. In Dévoluy and at low altitude in the Massif des Ecrins,these variations can be explained by the decrease in the number of freezing days related to the increase in the temperatures, which implies a slower reconstitution of the volume of debris stored between two events. But at high altitude it is currently difficult to establish the link between the climatic change and the dynamics of the debris flows because very little is known about the two variables controlling the triggering of the debris flows, i.e., on the one hand intense precipitations and on the other hand the volume of rock debris.     

南郑县近４３年气候资源变化特征初步分析

利用南郑县1966—2008年气象资料,运用统计学方法,分析光、热、水等气候资源以及蒸发、风等气象要素的变化,揭示该县气候资源变化的基本事实和变化规律。结果表明：南郑县近43 a来气温以0.137℃/10 a的气候倾向率呈上升趋势;≥5℃和≥10℃的积温总体呈上升趋势,≥15℃积温呈下降趋势;日照时数一年中呈单峰型,总体变化呈现下降的趋势;降水总体为下降趋势,春、秋两季为下降趋势,夏、冬两季为增加趋势,年暴雨出现频次呈减少趋势。     

黑龙江省冬半年寒潮变化的气候特征

使用黑龙江省信息中心整编的62个站点1961年1月1日-2010年2月28日日平均气温、日最低气温等气象要素,着重分析了黑龙江省冬半年寒潮频次的时空变化特征。结果表明,过去的近半个世纪,黑龙江省冬半年寒潮活动频次总的趋势是减少的,存在明显的年际和年代际变化,而且不同地形区寒潮频次也有明显差异,对所有台站进行Mann—Kendall检验,没有突变现象。使用GIS对黑龙江省不同的地形发生的寒潮频次进行分析,发现山区发生寒潮的频次比平原地带明显多。     

Climatic variations of ice conditions in different regions of the Barents Sea

Presented are the results of studying the regional peculiarities of climatic variations of spatiotemporal distribution of ice in the Barents Sea water area in 1977?C2010. Demonstrated is the dynamics of the interannual and seasonal variability of main elements of the ice regime (ice cover area, ice edge position, and ice period duration). Revealed are the common features and differences in the ice conditions in the water areas under study. It has been found that there is a significant feedback between the specific ice coverage in different areas of the sea. The climatic variations of the total ice coverage of the Barents Sea for the period of 1960?C2010 are analyzed using the electronic database on the Barents Sea ice coverage. It can be supposed that the current warm phase of climatic variations in the Barents Sea is coming to the end.     

Measuring and modeling black carbon (BC) contamination in the SE Tibetan Plateau

Black carbon (BC) concentrations were measured in the southeast (SE) Tibetan Plateau along the valley of the Yarlung Tsangpo River during winter (between November, 2008 and January, 2009). The measured mean concentration (0.75 μg m⁻³) is significantly higher than the concentrations (0.004–0.34 μg m⁻³) measured in background and remote regions of the globe, indicating that Tibetan glaciers are contaminated by BC particles in the Plateau. Because BC particles play important roles for the climate in the Tibetan Plateau, the sources and causes of the BC contamination need to be understood and investigated. In this study, a mesocale dynamical model (WRF) with BC particle modules is applied for analyzing the measurement. The analysis suggests that the major sources for the contamination in the SE Plateau were mainly from the BC emissions in eastern Indian and Bangladesh. Because of the west prevailing winds, the heavy emissions in China had no significant effects on the SE Plateau in winter. Usually, the high altitude of the Himalayas acts a physical wall, inhibiting the transport of BC particles across the mountains to the plateau. This study, however, finds that the Yarlung Tsangpo River valley causes a 'leaking wall', whereby under certain meteorological conditions, BC particles are being transported up onto the glacier. This too causes variability of BC concentrations (ranging from 0.3 to 1.5 μg m⁻³) in a time scale of a few days. The analysis of the variability suggests that the “leaking wall” effect cannot occur when the prevailing winds were northwest winds, during which the BC transport along the valley of the Yarlung Tsangpo River was obstructed. As a result, large variability of BC concentration was observed due to the change of prevailing wind directions.     

Estimates of snow accumulation and volume in the Swiss Alps under changing climatic conditions

Summary ¶Snow is a key feature of mountain environments in terms of the controls it exerts on hydrology, vegetation, and in terms of its economic significance (e.g. for the ski industry). Its quantification in a changing climate is thus important for various environmental and economic impact assessments. Based on observational analysis, surface energy balance modeling, and the latest data from high-resolution regional climate models, this paper investigates the possible changes in snow volume and seasonality in the Swiss Alps. An average warming of 4°C as projected for the period 2071–2100 with respect to current climate suggests that snow volume in the Alps may respond by reductions of at least 90% at altitudes close to 1000m, by 50% at 2000m, and 35% at 3000m. In addition, the duration of snow cover is sharply reduced in the warmer climate, with a termination of the season 50–60 days earlier at high elevations above 2000–2500m and 110–130 days earlier at medium elevation sites close to the 1000m altitude. The shortening of the snow season concerns more the end (spring) rather than the beginning (autumn), so that it should be expected that snow melt will intervene much earlier in the season than under current conditions. The results of this study are of relevance to the estimations of the impacts that the projected warming may have on the amount and timing of water in hydrological basins, on the start of the vegetation season, and on the financial status of many mountain resorts.     

近50年湖南省雷暴气候特征分析

根据湖南省74个地面气象站1961-2010年的雷暴日资料,利用数理统计、小波分析及Mann-Kendall检验等方法,对近50年雷暴气候特征进行分析.结果表明：1）湖南省雷暴日数空间分布特征为南部多、北部少,最大值出现在南部山地（65.38 d/a）,最小值出现在北部平原（21.92 d/a）,月平均雷暴日呈单峰值分布,3-9月为雷暴高发期;2）湖南省年平均雷暴日数存在8、16、24和30 a的周期变化规律,其中8 a周期振荡最显著;3）多雷期和少雷期的差异主要表现在副热带高压西伸脊点的位置以及青藏高原短波槽的位置和强弱上.     

贵州省近30a秋风的气候特征分析

利用1981—2010年30 a贵州省78站逐日日平均气温数据和NCEP/NCAR逐日的再分析资料,采用合成、EOF分解、傅立叶滤波等方法,分析了贵州省秋风的气候特征。结果表明:贵州省秋风天气强度有自西向东部或向东南部、东北部递减的分布规律。贵州省异常秋风过程次数的空间分布表现为全省各站呈同位相变化,进入2000年后,秋风过程次数由全省秋风偏弱偏少型转为全省秋风偏多偏强型。在环流场上,纬向西风在不断东移的过程中不断分裂出短波槽引导冷空气南下影响贵州,形成秋风天气过程,因而造成的秋风过程时间较长,强度较大。对秋风过程的环流场进行滤波表明:1波对于秋风过程有着十分显著的影响,而1波、2波在时间上的配合对于秋风过程也非常重要。     

Climatic conditions and their impact on viticulture in the Upper Moselle region

Climate parameters, especially temperature, sunlight, and precipitation, play a decisive role in growing and maturing processes. The aim of this study is to investigate the relationship between climate variability and variations in phenological events in viticulture. Long time series of daily meteorological observations are used to quantify these relations. The primary aim is to predict the date of phenological events by relationships between plant morphology and environmental conditions. Causal relationships between environment and internal activities of the vine (phytochemistry, cellular interactions, molecular and cell biology) are not our focus. The dates of the phenological events are important for planning treatments in the vineyards like pest management, for predicting the duration of the ripening phase and estimating the quality of the grapes and the vintage. The focus is layed on the region of the Upper Moselle, especially the Luxembourgian viticulture. First the regional climate and the phenological states of different vine varieties during the time period 1951?C2005 are analysed. Significant trends are detected in annual, spring and summer temperatures. Vine phenology is also found to have changed significantly; budburst date and flowering events occur earlier by about two weeks. In a second step, relationships between phenological events and climate parameters are used to develop a prediction model. The parameterisation used in this study is based on a linear multiple regression method with forward and backward steps. The predictors tested are mainly temperature means for different time periods or temperature derived indices. In addition precipitation and sunshine duration for different time periods are evaluated, but only the temperature based predictors showed sufficient skill. For the budburst event, the significant predictors are the accumulated degree days in March, the mean daily maximum temperature in April and the accumulated frost days from January to March. The flowering event is best predicted by the accumulated degree days in May and April, the mean daily maximum temperature in June, and the date of the budburst event. Depending on the vine variety and the phenological event, the model explains 80?C89% of the variance and has a correlation coefficient above 0.90 with the observations.     

天时、气候与中国历史(Ⅱ): "好(坏)天时"与历史上的"顺(乱)世"

中国历史上的"顺世"绝大多数(≈83%)出现在"好天时纪"中; 绝大多数"乱世"出现在"坏天时纪"内(≈85%).历史上的分裂期都出现在"长坏天时纪"中.依据"天时好、坏"与"顺世、乱世"的两两对应关系, 可将历史上的皇帝分为贤、明、庸、暴四类.本世纪初开始的"长好天时纪"可能是中华民族又一个辉煌时期的开始.但是对"坏天时代"的可能干扰, 应引起足够重视.     

近40年来甘肃省降水的变化特征

利用1960—2003年甘肃省59个测站逐日降水资料,研究了甘肃省四季和年降水量及雨日的气候变化特征。结果表明,平均年降水量和雨日的空间分布非常相似。河西和白银市的年降水量的趋势系数为正,省内其它地区为负;河西大部和甘南部分地区的年雨日的趋势系数为正,省内其它地区为负。线性倾向估计的结果表明,年降水量线性倾向值的零线基本以黄河为界,河西在增加,河东在减少,减少最明显的区域在徽县和康县盆地;雨日增加主要在河西西部偏南地区、沿祁连山的大部分地区及临夏以及甘南等海拔相对较高的地区,中部和陇东南的雨日在减少。雨日增多的地方降水量也在增加,反之亦然。全省年降水量和年雨日在1990年代均为低谷,而在21世纪初又都有上升趋势。降水量突变在1990年代中期;雨日突变河西在1960年代后期,河东在1970年代后期和1990年代中期。冬季降水量及雨日表现全省性大范围的增加趋势,秋季降水量及雨日亦呈全省性减少趋势;而春、夏季的降水量及雨日变化趋势则是地区性的。     

近40年十堰市雷暴气候变化特征分析

利用1971-2010年十堰市7个气象观测站逐日雷暴资料,通过数理统计、小波变换、EOF分析和M-K检验,讨论了十堰市雷暴气候变化特征。结果表明,在近40年雷暴日数总体变化呈减少趋势,每10年雷暴日数减少1.26天,全年雷暴天数达23.5天。除12月无雷暴发生外,其余十一个月均有雷暴发生,4-9月雷暴日数占全年的94.5%,其中7-8月占58.7%,属于强雷季节。雷暴具有显着的年际和年代际变化特征,存在6年的显著年际周期,雷暴突变时期出现在20世纪80年代初。     

基于经验法则的水稻细菌性条斑病气候年型分析

利用广东省化州市1989-2016年晚稻细菌性条斑病资料和同期气象资料,采用合成分析和秩相关分析,筛选出影响细菌性条斑病发生的关键气象因子;基于经验法则,利用水稻细菌性条斑病发生阶段的温度、降水距平,判别细菌性条斑病发病程度,并确定了细菌性条斑病发生流行的气候年型与预测指标。经历史回代,判别细菌性条斑病发病程度符合率为82.1%,并进行了2017-2019年的外延指标判别,符合率达100%,综合判别符合率在83%以上。     

Climatic zoning for the calculation of the thermal demand of buildings in Extremadura (Spain)

The present work reports on a methodology to assess the climatic severity of a particular geographic region as compared to specific information available in the current regulations. The viability for each of the 387 municipalities in the Autonomous Community of Extremadura (Spain) is analysed, making a distinction between those with reliable climate reports and those for which no such information is available. In the case study, although the weather conditions in Extremadura are quite homogeneous according to the Spanish Technical Building Code (STBC 2015) classification and most areas are associated to zone C4 (soft winters and hot summers), the southern area in the region is associated to zone D1, similar to the north of Spain, where winters and summers are cool, which does not coincide with the actual climate in the south of Extremadura. The general climatic homogeneity in Extremadura was also highlighted with the new procedure, predominating zone C4, but unexpected or unreal climatic zoning was not generated, giving place to a consistent spatial distribution of zones throughout the region. Consequently, the proposed method allows a more accurate climatic zoning of any region in agreement with the Spanish legislation on energy efficiency in buildings, which would enhance the setting of thermal demand rates according to the actual climatic characterisation of the area in which a particular municipality is located.     

近54a湖南区域暴雨的时空分布特征

基于1960—2013年湖南88个台站逐日降水数据,采取线性趋势分析等方法分析了近54 a湖南区域暴雨的时空分布特征。从时间变化上看,近54 a湖南区域暴雨日以6月208 d为最多,1月0 d为最少;夏季、春季、秋季及冬季区域暴雨日数占总日数的百分比依次为60%、29%、10%及1%。暴雨日数、暴雨强度均值突变点分别为1994年、1995年,暴雨初日的均值突变点为1983、1994年,暴雨终日无均值突变;暴雨日数与暴雨强度(暴雨发生终日)总体上呈上升(后延)趋势。基于突变点分段线性趋势分析表明,仅暴雨日数在1994—2013年及暴雨强度在1960—1994年期间呈显著下降趋势。从空间分布上看,区域暴雨强度及其与非区域暴雨强度的差值、区域暴雨持续2日或以上的暴雨强度及其与单日暴雨强度的差值的大值区主要位于湘西北及湘东南,小值区主要位于湘西南-湘东北的带状区域;全部站点的区域暴雨强度均大于非区域暴雨强度,89%的台站持续2日或以上的区域暴雨强度大于单日区域暴雨强度。区域暴雨、总体暴雨的台站暴雨最长持续日数分别为1~4 d、2~4 d,均集中在2~3 d且其站数占总站数的百分比分别为97.7%、96.6%。     

近55年广西融水县降水气候特征分析

利用融水县气象站1959-2013年的降水资料,采用数理统计和线性倾向估计分析方法,分析了融水县降水分布特征及其变化规律。结果表明：融水县降水分配不均,主要集中在4-8月,6月最多,5月次之;年暴雨日数6.9d,暴雨持续时间多为1d,最长4d;近55年来融水县年降水量和汛期（4-9月）降水量均呈减少趋势,每10年分别减少16mm和6mm,而主汛期（5-8月）的降水量却呈增多趋势,每10年增加13mm,这预示着融水县未来降水可能更趋于集中在主汛期（5-8月）,发生洪涝灾害的几率可能增多。此外,一日最大降水量呈增多趋势,预示未来降雨强度可能增大;春、秋季的降水量呈减少趋势,提示未来发生春旱、秋旱的几率可能增多。     

冷涡背景下辽宁龙卷气候特征和环境条件

为了研究冷涡与辽宁龙卷的关系,揭示冷涡背景下辽宁龙卷发生的特征,利用1951—2020年辽宁省龙卷观测和灾情数据以及欧洲中期天气预报中心ERA5大气再分析资料,收集整理冷涡背景下辽宁龙卷个例,对比冷涡背景下EF2—4级(EF2+)和EF0—1级(EF1?)龙卷物理量参数的差异.结果表明:(1)冷涡背景下辽宁龙卷主要出现...