【作者】 张鹏；

【导师】 戚大伟； Hans Linderholm；

【作者基本信息】 东北林业大学 ， 森林工程， 2012， 博士

【摘要】 在全球气候变化的背景下,了解和掌握地球过去的气候变化和大尺度大气环流状况有助于我们对目前的气候状况及其影响因素做出正确评估,也能为气候模型的建立提供数据支持。理解斯堪地那维亚地区气候的时空特征及其与夏季北大西洋涛动的联系对了解高纬度地区过去的气候变化和夏季北大西洋涛动的历史演变具有重要意义。本文主要利用欧洲赤松(Pinus sylvestris)树木年轮宽度指标探讨斯堪地那维亚中西部地区沿东-西横断面树木径生长与温度和降水的响应关系,重建Storlien地区夏季平均温度,增加斯堪地那维亚地区温度重建网络节点,利用斯堪地那维亚地区欧洲赤松、欧洲冷杉(Picea abies)和欧洲桦(Betula pubescens)组成的树木年轮网络,探讨该地区树木年轮生长类型的时空分布及其与夏季北大西洋涛动的联系。以斯堪的纳维亚中西部地区沿东-西横断面五个样点的树木年轮宽度序列和五个气象站的温度和降水数据为基础,对树木年轮气候响应关系进行分析得出,斯堪的纳维亚中西部地区气候整体受海洋影响较大,温度和降水沿东-西方向呈明显的梯度分布。该地区树木年轮样本的序列间相关系数和敏感度较高,树木生长受前一年的气候状况影响较大。各序列的平均轮宽、一阶自相关系数和序列内相关系数均呈现随地理位置由西至东逐渐增大的变化趋势,体现了海洋气候对各样点序列特征的影响。生长季温度是该地区树木生长的主要限制因子,五个样点轮宽年表均能够较好地反映当地七月平均温度变化情况。年表与气候因子的响应关系呈现在内陆地区较强,在临海地区较弱的特点。在过去250年时间里,位于内陆四个样点的树木生长具有较高的相似性,临近海洋的Nonshaugen样点树木生长与其它地区树木相关性表现出随时间变化的规律。五个样点树木年轮年表与七月平均温度的相关关系在20世纪下半段较20世纪上半段有明显的减弱,相关范围缩小,并且相关中心有从北向南移动的迹象。利用Storlien地区的树木年轮宽度指标对该地区夏季温度进行重建,基于ARSTAN年表和差值年表的Storlien地区夏季温度重建分别解释了该地区夏季平均温度变化的30%和28%。该重建与Jamtland树木年轮最大晚材密度暖季温度重建在20世纪以前拟合程度较高,在20世纪后Storlien地区重建温度没有如Jamtland树木年轮最大晚材密度暖季重建温度一样骤然升高人。分析认为,这是由于Storlien样点距离海洋较近,海洋对气候的调节作用,使该地区树木年轮生长增量没有位于内陆的样点显著。内陆样点温度重建包含了更多的周期信号,而且存在两个较长的周期,而距海洋较近的Storlien样点所具有的周期信号较少,基本集中在3-5年和11-12年左右。Storlien地区距离海洋较近,整个地区的气候特点相对内陆更加单一,所以反映的信号也更少且更强。利用旋转主成分分析方法将斯堪的纳维亚地区树木年轮生长类型分为西北和东南两个区域。1860年至1978年的公共时段各样点按照空间位置相近程度聚合。树种因素没有影响该地区树木生长的分区状况,表明斯堪的纳维亚地区的区域气候因子差异决定了该地区树木年轮的生长类型。温度和降水分别为西北和东南两分区树木年轮生长的主要限制因素。随着时间变化,树木年轮生长类型,平均敏感度和树木年轮生长的一致性均发生改变。分析认为,夏季北大西洋涛动和20世纪全球温度升高均对该地区树木年轮生长变化产生影响。树木年轮生长类型的变化可以从一定程度上反映气候变化信息和大尺度气候环流状况。其中斯堪的纳维亚中西部地区树木年轮生长类型对气候变化反应最为敏感。更多还原

【Abstract】 In the background of global climate change, knowledge of past climate variability and large-scale atmospheric circulation helps to accurately assess the current climate status in a historical context and the human impacts on climate change. In addition, it also provides paleoclimatic data to evaluate the ability of climate models to simulate realistic climate changes. Understanding temporal and spatial characteristics of climate in Scandinavia and its relationship with summer North Atlantic Oscillation is helpful for us to get the knowledge of past climate variability and large-scale atmospheric circulation in high-latitude region. In this thesis, tree ring width proxies of Scots pine were used to investigate the response of tree ring growth to temperature and precipitation along west-east transect in west-central Scandinavia, and used to reconstruct the average summer temperature of Storlien that enriched the temperature reconstruction networks based on tree ring width proxies in Scandinavia. The tree ring width chronology networks including multiple tree species such as Scots pine, Norway spruce and European birch in Scandinavia were used to investigate the temporal and spatial distribution of tree ring growth mode in this region and it relationship with summer North Alantic Oscillation.Five tree ring width series derived from five sites along west-east transect in west-central Scandinavia were used to do the response analysis against temperature and precipitation data collected from five meteorological station along the transect. The results showed that the Atlantic Ocean had a big impact on climate in west-central Scandinavia, while temperature and precipitation along west-east transect showed a significant gradient distribution. Tree ring width series in these five sites showed high series intercorrelations, high average mean sensitivities, and high value on first order autocorrelations which emphasized the effect of precedent year’s climate on the current year’s tree ring growth. The statistical characteristics of these tree ring width series such as average ring widths, first order autocorrelations, and series intercorrelations showed a gradually increasing trend along the west-east direction which underlined the Atlantic Ocean effect on tree ring growth characteristics. Growing season temperature was a primary limiting factor of tree ring growth in this area. Tree ring width series in these five sites could well reflect local July average temperature variation. Tree ring width indexes and July average temperature showed a stronger response relationship in inland area compare with that in oceanic area. In the past250years, tree ring growth variation in the four inland sites showed a high homogeneity, while tree ring growth variation in the most oceanic site of Nonshaugen showed a significant changing correlation with tree ring growth in other sites along the time. Significant decreasing correlations between five tree ring width chronologies and July average temperature appeared in the second half20th century comparing with those in the first half20th century. At the same time, the area of tree ring chronology-July average temperature spatial correlation extent decreased, and correlation center had moved from north to south.Tree ring width proxies of Scots pine were used to reconstruct the average summer temperature of Storlien. The temperature reconstructions based on ARSTAN chronology and residual chronology separately explained30%and28%variation of Storlien average summer temperature. The reconstructions well correlated with Jamtland Maximum latewood density (MXD) warm season temperature reconstructions before20th century. In20th century, the Jamtland MXD reconstructions showed a distinct increase of warm season temperature which didn’t appear in the Storlien reconstruction. This was probably due to the adjustment of Atlantic Ocean on climate which induced less distinct increase of tree ring growth in Storlien than of that in inland sites. The results showed that the inland reconstruction contained more periodic signals including tow long cycles than that of Storlien reconstruction which primarily contained two cycles of3-5years and11-12years. We inferred that the stable climate in Storlien caused by the ocean impact leaded to less but stronger periodic signals in tree ring series in Storlien than that in inland sites.Based on multiple-species tree ring width chronology networks, rotated principal component analysis was used to divide tree ring growth mode into tow types in Scandinavia. One type contained the tree ring series from the sites mainly located in north-west area, the other type contained the series from the sites mainly locate in south-east area. The results showed that in the period of AD1860-AD1978, the tree ring growth modes were clustered according to the approximation degree of the locations of sampling sites. The factor of tree species didn’t influence the cluster results which indicated climate factors were the most significant factors on determining the tree ring growth modes in Scandinavia. Temperature and precipitation were separately the primary limiting factors of tree ring growth in north-west mode and south-east mode. Tree ring growth modes and average mean sensitivity in Scandinavia changed along the time. We inferred that summer North Atlantic Oscillation and the20th century global warming had a big influence on tree ring growth mode in Scandinavia. The classification of tree ring growth modes could reflect changes of climate and large-scale atmospheric circulation. The west-central Scandinavia was the most sensitive area of Scandinavia concerning the response of tree ring growth modes variations to climate changes.更多还原