Summer Moisture Variability in East Central Sweden Since the Mid-Eighteenth Century Recorded in Tree Rings

To make predictions of future climate it is necessary to understand the past climate—temperature as well as precipitation. While a wealth of temperature proxies exist from northern latitudes, there is still a lack of information about past precipitation variability. Here we present a 300‐year‐long tree‐ring width chronology from xeric‐site Scots pines (Pinus sylvestris L.) in Tyresta National Park, east central Sweden. Tree‐ring widths were compared to the long observed temperature and precipitation records from Stockholm during 1786–2000. Analyses of the climate/growth relationship showed that, in general, May–June precipitation had a dominating influence on pine growth. However, during dry periods, negative responses to June–July temperature were stronger, especially evident in the late nineteenth century. Periods of below‐average growth were associated with dry conditions in May–June, but occasionally periods of wet and cool summers also produced narrow rings. Periods of above‐average growth were linked to wet, but sporadically also cool and dry, early summers. The years between 1815 and 1833 appear to be particularly dry in the 300‐year context. Since growth anomalies are found in other Swedish drought‐sensitive tree‐ring chronologies during this period, it is likely that this dry period had a regional extent. This is the first tree‐ring chronology from southern Sweden that provides multi‐century information of past summer drought and moisture variability with high resolution and the study will add important information regarding past climate variability in southern Sweden.     

CONTRASTING TREE‐RING GROWTH RESPONSE OF PICEA ABIES TO CLIMATE VARIABILITY IN WESTERN AND EASTERN ESTONIA

Climatic variations and changes regulate arboreal growth. In Estonia, the tree‐ring growth variability of coniferous and deciduous trees has been linked with various climatic variables in different parts of the country. However, the dendroclimatic signals of Norway spruce (Picea abies (L.) H.Karst.) have not been explored across the region. Here we compare the growth variability of this species, growing under various site conditions in Estonia, with records of temperature, precipitation, and indices of the North Atlantic Oscillation over a period of 50 years (1956–2005). Western chronologies correlated positively and significantly (p<0.01) with early‐summer (June) precipitation, while eastern chronologies showed positive and significant (p<0.05) correlation with mid‐winter (January) precipitation. Moreover, the eastern chronologies correlated positively and significantly (p<0.05) with the North Atlantic Oscillation index in January. First, our results indicated that the previously established geobotanical division, rather than forest site types, most probably explains the spatial patterns in spruce growth variability. Second, our findings agreed with the late Quaternary pollen studies showing that the vigour of spruce is limited in the western forests by a combination of climatic (i.e. summer moisture) and edaphic factors. Third, our results complement those of previous investigations, suggesting that the impacts and threats the changing climate will pose on spruce may be different in western and eastern Estonia, with more severe effects envisaged in the western part of the region through drought‐induced physiological stress.     

雪岭云杉树轮宽度对气候变化的响应

利用新疆伊犁地区雪岭云杉的6个树轮宽度年表 ,通过相关分析的方法,分析不同地形条件下雪岭云杉树轮宽度对于气候要素的响应。统计分析表明,雪岭云杉对气候变化比较敏感,在北天山南坡的森林下限,雪岭云杉生长与生长季7~8月降水关系显著;在南天山北坡的森林下限,雪岭云杉生长对生长季前11-次年1月最低温度存在显著正相关。地形对雪岭云杉与气候要素之间的关系影响较大,在南天山北坡,由于森林上下限树木抗寒性的差异,森林下限树木生长对温度的响应强于上限树木;南北坡引起的降水量水平的差异,使得天山不同坡向的树木生长响应不同的气候要素。     

Longleaf Pine (Pinus palustris Mill.) Morphology and Climate/Growth Responses Along a Physiographic Gradient in North Carolina

Geographic differences in tree morphology and climate and growth responses of longleaf pine have been documented, yet how these differences vary at a larger scale has not. In this study, we documented changes in tree morphology and climate and radial growth responses of six longleaf pine (Pinus palustris Mill.) stands in three physiographic regions in North Carolina. We sampled from more than fifteen trees per stand and compared site- and regional-level total and latewood ring width values to temperature, precipitation, and drought. All morphological characteristics expressed a strong west–east gradient. Climate and radial growth response was strongest for the Sandhills region and then Piedmont and Coastal Plain regions. The distinct morphological characteristic gradient did not covary with climate and radial growth response, suggesting that additional environmental influences affect needle length, trunk diameter, and height.     

CLIMATE RESPONSE FUNCTIONS FOR BIGCONE SPRUCE: A MEDITERRANEAN CLIMATE CONIFER

Bigcone spruce is a conifer endemic to southern California. Two new tree-ring chronologies were developed utilizing individuals of this species growing at two sites in the San Rafael mountains of Santa Barbara County. Climate growth response functions were determined for these chronologies and for an existing bigcone spruce chronology from the San Bernardino mountains farther east. Bigcone spruce is particularly well suited for dendrochronological analysis given its longevity (800 years) and the strong relationship between growth and precipitation. Growth in the current year depends strongly on growth in the previous two years (22-46% of total chronology variance). After removing the effects of prior growth, response functions based on precipitation alone account for 43-51% of chronology variance, while those based on precipitation and temperature explain 52-76% of total variance. Response functions indicate a strong positive relationship between growth and winter and spring precipitation, and a negative relationship with early spring and early summer temperatures. The response functions for big-cone spruce are distinctive from those published for other western conifers, and are consistent with the unique characteristics of the mediterranean climatic regime.     

RADIAL GROWTH OF HUASHAN PINE AND ITS RESPONSE TO CLIMATE

Intr0ducti0nltiswell-knownthattl1eannualringSoftreeprovideuniqueinformationfOrdeductionofpastclimaticchange.ProPertiesoftreeringrsuchaswooddensityandringwidthvaryinresPOnsetoclimaticc0nditionsthatlimittreegrowth[7,l4].ByunderstandingtherelationsllipsbetweentreegroWthandclimatevariables,PaStclimaticvariationscanbederivedfromtree-ringdata.InChina,mostdendroclimaticstudieshavebeenconductedonclimaicallyextremesites[l2,l8,l9].TreesgrOwingonsuchsiteshavestrongandstraightfO~relationshipswithclim…     

祁连山中部树木年轮宽度与气候因子的响应关系及气候重建

研究了祁连山中部不同海拔高度青海云杉的树轮宽度对气候因子的响应,重建了祁连山中部 230 a以来春季3~5月的降水和 170 a以来夏季6~8月的气温序列。结果分析发现,不同高度的云杉树轮生长对春季降水极为敏感,呈现显著正相关;对夏季气温的响应程度,各海拔高度却不相同,夏季气温对上、下限云杉生长有显著影响,但对于森林中部云杉作用并不明显,总体表现为负相关,夏季高温对树木生长不利。气候重建结果发现,祁连山中部的春季230 a以来经历了大幅度长阶段的干湿变化,存在明显的 69 a和 21a周期;170 a以来夏季气温变化频繁,存在明显的2~4a周期。目前,祁连山中部正处于相对干旱和温暖时期,呈现出向暖干方向发展的趋势。     

大别山地区黄山松和油松树轮宽度的气候意义

本文基于2010年采自大别山地区黄山松、油松树轮资料分别建立了树轮宽度标准年表,利用相关函数检验了年表与附近的麻城气象站1959-2009年月平均最高气温、月平均气温、月平均最低气温和月降水量之间关系,旨在探讨黄山松、油松树轮宽度的气候意义。研究结果显示,平均敏感度、标准差、信噪比等统计量黄山松年表均高于油松年表,表明黄山松年表较油松年表包含更多的气候信息,具有更高的树轮气候学研究价值。黄山松径向生长主要受当年2-7月平均气温限制,任何月份及月份组合降水量对黄山松径向生长的限制作用均不显著;油松径向生长主要受当年5-6月降水总量限制,任何月份及月份组合气温对油松径向生长的限制作用均不显著。研究表明,在中国亚热带暖湿地区,气候要素的年际变化亦可对部分树种径向生长具有较强的限制作用,树木年轮宽度的变化对气候具有指示意义。研究结果将进一步弥补中国亚热带暖湿地区树轮宽度年表的不足,为树轮气候重建研究提供参考和依据。     

RESPONSE OF A MONTENEGRO GLACIER TO EXTREME SUMMER HEATWAVES IN 2003 AND 2007

The Debeli Namet glacier in the Durmitor massif, Montenegro, is one of the lowest altitude glaciers (2050–2300 m) at this latitude (42–44°N) in the northern hemisphere. The glacier survives well below the climatological equilibrium line altitude because of substantial inputs from avalanching and windblown snow. The glacier survived two of the hottest summers on record in 2003 and 2007, although it experienced significant retreat. However, during the intervening years (2004–2006) the glacier increased in size and advanced, forming a new frontal moraine. This rapid advance was primarily in response to much cooler summer temperatures, close to or cooler than average, and a marked increase in winter precipitation. The rapid growth and decay of the Debeli Namet glacier in response to inter‐annual climate variability highlights the sensitivity of small cirque glaciers to short‐term climate change.     

树轮密度对气候的响应及重建研究进展

树轮密度是重建过去气候变化的重要代用指标。过去几十年,国内外学者针对树轮密度开展了大量的研究工作,取得了丰硕的成果。论文收集了国内外有关树轮密度的研究文献,从树轮密度对气候变化的响应和气候重建等方面进行了概述。尽管树轮密度对气候变化的响应可能受到样点的地理位置、地形(如海拔、坡向等)、树种等因素的影响,但湿冷地区树轮晚材最大密度能较好地反映生长季或生长季末期温度变化;而干旱地区的早材平均密度能揭示生长季早期的降水变化。因此,目前大多数研究以重建生长季或生长季末期温度为主,也有重建降水量、海平面气压变化的案例。此外,重建方程的方差解释量存在空间和树种间的差异,但这些差异需要更多的研究工作加以验证。最长的重建序列来自于欧洲,长达2018 a;国内基于树轮密度重建的最长温度序列来自于西南地区,长达449 a。另外,树轮密度序列在对温度响应的分异性问题以及评估强火山喷发的降温效应方面还存在争议。其争议源于树轮密度与温度关系还受到其他环境变量与人为因素的影响,因此今后研究还需关注树轮密度与降水、光照等其他气候变量的关系,同时也要注重树种、海拔、实验方法等非气候因子的影响。     

祁连山东部地区树木年轮年表的建立

利用采自祁连山东部的祁连圆柏样芯,经常规程序晾干、固定、打磨、定年和读数后,建立了标准化年表,并将标准年表的树轮指数与采样点附近的天祝乌鞘岭气象站的温度和降水进行了相关分析。结果表明,年轮指数与3~4月降水呈显著正相关,相关系数达0.525。由于3~4月份的降水为该地区树木生长季之初的降水,是树木生长的限制因子,因此该相关具有明确的生物学意义。研究还发现,年轮指数与1月气温也呈显著负相关(相关系数为- 0.297),这可能是由于冬季最冷月气温偏高时,影响树木代谢和土壤湿度,从而影响树木的生长。祁连山东部地区树木年轮年表具有明确的气候学意义。     

牛背梁自然保护区林线不同海拔巴山冷杉径向生长对气候变化的响应

近年来气候变化对秦岭植被的影响已得到众多研究的证实,牛背梁作为秦岭东部主脊和国家级自然保护区,该地区亚高山林线植被对气候变化的生态响应现状尚未得到广泛关注。依照树木年代学原理,进行响应分析并建立回归模型,探讨了牛背梁林线关键树种巴山冷杉（Abies fargesii）年表特征及对气候响应的海拔分异特征。结果表明：（1）随海拔升高,树木生长对气候的敏感性逐渐上升,但轮宽年表的同步性和信号强度呈先下降后上升的特点。（2）不同海拔树轮宽度年表的气候响应结果基本一致,对气温的敏感性均较降水强,敏感时段为当年2～8月,差异主要体现在,高海拔树木受生长季末期8月气温的影响较重,中海拔树木受生长季前期3～4月降水和上年冬季10～11月气温的促进,而低海拔树木受初春1～2月降水的限制作用明显。（3）对比分析低、中、高海拔3个回归模型中显著因子的变化趋势,发现气候变化可以促进巴山冷杉生长季的提前,但不同海拔树木的生长动态各异,说明研究区林线不同海拔巴山冷杉生长对全球变化可能具有不同的响应机制。     

南极地区冰雪消失对全球大气环流和气候影响的数值模拟

本文利用全球大气环流模式通过数值模拟研究了北半球夏季南极地区冰雪覆盖的消失对大气环流和全球气候影响的过程。结果表明南极冰雪消失不仅影响南半球大气环流异常,而且通过引起热带环流异常如增强东亚季风环流和减弱Walker环流等引起北半球大气环流和我国夏季气候的异常。南极冰雪覆盖的消失将给全球气候带来严重后果。文中也对南极冰雪气候效应的动力学机制进行了讨论。     

近50a新疆气候变化对环境影响评估

利用新疆比较完整的气象观测记录，分析温度与降水的时空变化。结果表明，新疆气候变化与全球和全国气候变化趋势基本一致，但又具有显明的区域性特点：变暖脚步渐缓，增温势头不减。与此相伴随的暴雪、暴雨、低温冷害和干旱等气候极值事件频频出现，而寒潮天气明显减少，导致冬季增温高于夏季，使新疆光热资源变幅及时空分布发生变化。近50a，尤其近10多年来，气候的明显变温对新疆的生态与环境的变化有积极的影响，使新疆的农牧业结构悄然发生变化，对国民经济的发展起促进作用。     

新疆气候与环境的过去,现在及未来情景

在分析近年来新疆地质时期与历史时期气候与环境研究方面大量的文献资料与成果,并对现代器测时期的气候变化问题进行讨论的基础上,利用综合分析法构画了新疆下世纪上半叶气候与环境的可能情景,认为新疆气候与环境初期于的晚白垩世,主要形成于第三三纪,至今总的干旱情并未改变。     

福建三明马尾松树轮宽度对气候变化的响应

运用树木年代学的基本原理和方法,研究三明地区马尾松(Pinus massiniana)径向生长对气候要素的响应。结果表明:夏季温度限制着马尾松的径向生长,年轮宽度与上一年和当年7—8月平均气温均呈显著负相关(P0.01);马尾松的径向生长受到降水和湿度的影响较大,与上一年1—3月降水量和2—3月平均相对湿度显著负相关(P0.01),与当年6—11月平均降水量和7—8月相对湿度显著正相关(P0.01);同时宽度年表与上一年2—3月太阳日照时数显著正相关(P0.01);另外,宽度年表与6—11月PDSI显著正相关(P0.05),生长季的干旱胁迫抑制了马尾松的生长。研究说明本地区限制马尾松树木生长的因素较多,1年中不同时期限制马尾松径向生长的气候因子不同。     

ORPOM model for optimum distribution of tree ring sampling based on the climate observation network

Tree ring dating plays an important role in obtaining past climate information.The fundamental study of obtaining tree ring samples in typical climate regions is particularly essential.The optimum distribution of tree ring sampling sites based on climate information from the Climate Observation Network(ORPOM model) is presented in this article.In this setup,the tree rings in a typical region are used for surface representation,by applying excellent correlation with the climate information as the main principle.Taking the Horqin Sandy Land in the cold and arid region of China as an example,the optimum distribution range of the tree ring sampling sites was obtained through the application of the ORPOM model,which is considered a reasonably practical scheme.     

Reconstruction of summer temperature variation from maximum density of alpine pine during 1917?2002 for west Sichuan Plateau, China

Having analyzed the tree ring width and maximum latewood density of Pinus den-sata from west Sichuan, we obtained different climate information from tree-ring width and maximum latewood density chronology. The growth of tree ring width was responded princi-pally to the precipitation in current May, which might be influenced by the activity of southwest monsoon, whereas the maximum latewood density reflected summer temperature (June–September). According to the correlation relationship, a transfer function had been used to reconstruct summer temperature for the study area. The explained variance of re-construction is 51% (F=52.099, p<0.0001). In the reconstruction series: before the 1930s, the climate was relatively cold, and relatively warm from 1930 to 1960, this trend was in accor-dance with the cold-warm period of the last 100 years, west Sichuan. Compared with Chengdu, the warming break point in west Sichuan is 3 years ahead of time, indicating that the Tibetan Plateau was more sensitive to temperature change. There was an evident sum-mer warming signal after 1983. Although the last 100-year running average of summer tem-perature in the 1990s was the maximum, the running average of the early 1990s was below the average line and it was cold summer, but summer drought occurred in the late 1990s.     

两极海冰与青藏高原陆面物理过程“耦合”特征

为探讨南极、北极强信号区域海冰变化 ,青藏高原陆面热力状况与北半球大气环流及中国气候变异的遥相关特征以及“三极”因子间的“互反馈”机制 ,应用遥相关等统计方法研究了影响东亚以及中国区域气候变化特征前期“三极”强信号特征 ,探讨了两极海冰与高原陆面水热状况之间的“耦合”影响及其“互反馈”相关特征 ,比较了“三极”前期因子对中国夏季气候变异的贡献程度及其动力结构形成的影响特征 ,并从全球海 -陆 -气 -冰相关定性模型来认识全球气候变化与中国区域气候变异的形成机制。     

采用树木年轮资料重建山东沂山地区200多年来的湿润指数*

在中国,尤其在中国西北部地区,树轮年表是古气候信息的一个重要来源.由于某种原因,中国东部地区少有树轮研究工作.该文通过运引ARSTAN程序,建立并研究了山东境内沂山地区的树轮主年表(1750～1992).树轮和气候要素的响应面分析得出沂山地区的树轮生长和温度降水呈非线性相关,因此使用传统方法重建单个气候因子是不合理的.通过响应函数和回归分析,5月至8月份的湿润指数(P/T)被确定为重建对象,该湿润指数值代表了温度和降水对树轮生长的共同影响,且相关性很高,远超过信度检验.利用线性回归方法,获得重建湿润指数的预报方程,用树木年轮年表重建了自1750年以来的沂山地区逐年5月～8月湿润指数的变化.分析了沂山地区湿润指数重建的可靠性.