华北平原东部地区晚更新世以来的孢粉序列与气候分期

本文应用图象识别方法,对华北平原东部地区(宝坻—濮阳)的五口井和一个剖面的孢粉资料进行了研究,将本区晚更新世晚期一全新世地层划分为五个孢粉组合带,七个孢粉组合亚带,共建九个孢粉植物群演化阶段。在此基础上根据植物生态特征,探讨了两万年以来的气候演变,确立了九个气候期,并发现全新世以来气候变化具有八次明显的降温及七次升温过程,存在着二千五百年及千年左右的波动周期     

全球气候变化的成因初探

温室效应不是气候变化的唯一因素,温室气体的主体不是二氧化碳而是水汽.当水汽凝聚为云,就会遮蔽阳光,起到降温作用.太阳辐射量变化不足以解释气候变化的振幅,关键在于存在太阳能量积累和释放的多种效应,其中“海底藏冷效应”和“海洋锅炉效应”最为显著.太阳能在地球各圈层的不同分配也是地表气候变化的原因之一,其中“地磁层漏能效应”和“臭氧洞漏能效应”最为显著.气候变化周期是天文周期微力激发的结果,其能量来自太阳能量的长期积累.目前处于1500～1800年气候周期的变暖高峰,200年气候周期的变冷初期,60年气候周期的变冷阶段.本文通过历史资料反复核对,证实太阳黑子延长极小期、太阳黑子周期长度大于11年时期、潮汐极大期、低温有明显的对应关系,已经查出重复出现两个连续周期,除太阳活动变化外,强潮汐是其形成的原因.全球气候有准60年、200年、18000年等周期,这些周期与潮汐周期有很好的对应关系.特别是179～200年周期,在太阳黑子活动、潮汐变化和冷暖变化中都有明显的表现,形成对应的周期规律.分析结果显示,气候冷暖变化的原因不只限于大气层本身,而确有可用于气候预测的星体运行的变化信息.规律表明,2007年开始的太阳黑子延长极小期和潮汐极大期使我国可能进入严重低温冻害时期,并将在2020年达到高潮,必须做好预防准备.     

石笋记录的年际、十年、百年尺度气候变化

通过石笋微层沉积响应自然周期过程的分析 ,再次获得石笋微层韵律基本按年旋回的认识 .在连续石笋年层序列中发现持续十年以上的气候异常以及各种类型的气候快速变化 :均值突变、变率突变、趋势突变、周期突变 .石笋年层记录了从年际到十年、百年各种时间尺度的气候波动 ,是研究历史时期短尺度气候变化的有力材料 .     

黄土高原我的歌

气候环境是人类赖以生存的重要条件,对人类历史有着深刻的影响,了解过去的气候使我们对人类历史演变的认识向前迈进了一大步。而现在我们能够直接测量的气候历史才几百年,只是气候变化中很小的一部分。那么,我们该如何了解历史的从前的气候变化呢？在科学技术充分发达的今天,科学家是通过各种“岩石”的记录来了解地球气候系统过去的变化。这些“岩石”包括海洋沉积物、冰堆积物、风尘堆积物、珊瑚、……。     

晚新生代东亚气候变化：进展与问题

晚新生代东亚季风和干旱气候的形成和演化及其与青藏高原生长、全球气候变化的关系一直受到关注,但存在着不同看法．本文分析了近年来国内外在晚新生代东亚气候研究方面的新结果,讨论了亚洲季风和干旱气候阶段性和周期性演化的特征,在此基础上,分析了东亚气候变化与全球冰量／温度变化、高原隆升等的联系．我们的研究认为,青藏高原隆升驱动不能全面合理地解释晚新生代以来东亚气候演化过程,全球冰量和北半球温度变化在驱动东亚气候阶段性变化方面具有显著作用．此外,晚新生代大气CO2浓度变化对东亚气候大尺度演化的影响值得进一步重视,它可能是通过影响全球温度的波动和高纬／低纬的温度梯度,进而驱动热带辐合带（ITCZ）和季风气候带摆动,来影响东亚季风和干旱气候的演化的．在未来研究中,需要格外重视地质记录与数值模拟的结合．其中,古气候变化的高精度定量记录、区域异同及高原不同区域差别隆升的环境效应可能是突破点之一．     

观点

正中国气象局:三峡工程对气候影响小面对近十年来全球普遍出现的极端气候状况,国际上出现了不少对于大型人造工程的质疑。中国气象局和世界气象组织7月1日在瑞士日内瓦发布的"三峡工程气候效应评估报告的决策者摘要(SPM)"认为,三峡水库对附近的气候有一定影响,但影响明显的范围不超过20公里。全球气候变化是极端天气气候事件频发的大背景,     

用树轮α-纤维素δ13C重建天目山地区 近160年气候

对采自天目山的柳杉树轮进行交叉定年后,测得树轮的δ13C年序列.经谱分析,树轮的δ13C变化有与厄尔尼诺事件基本一致的准4.4年的周期.将δ13C年序列去除大气CO2的影响,利用其附近气象站资料,分析δ13C对气候要素的响应.结果表明天目山地区的树轮δ13C的高频振荡与季节的气温、降水等要素有显著相关,并有滞后效应,此外还与东亚季风的强弱变化有一定关系.通过建立回归方程重建浙江北部地区的气候序列,分析了这一地区一百多年来的气候变化状况及演化趋势.     

太白山三清池湖泊沉积记录的全新世气候变化及周期讨论

通过对太白山三清池湖泊沉积柱芯的低频磁化率(χlf)、频率磁化率(χfd)、总有机碳(TOC)、粒度参数指标的时序序列进行小波分析,探讨太白山全新世气候变化过程及周期波动性.结果显示:中、晚全新世太白山气候变化具有明显的阶段性特征;千年尺度上,χlf、χfd、TOC和平均粒径参数序列反映的主周期分别为1427、1427、1427和1452 a,晚全新世5410 cal a B.P.距今期间存在8次显著的冷暖交替震荡;在百年尺度上,χlf、χfd、TOC和平均粒径参数序列还揭示出分别以492、492、467和467 a为周期的次一级变化,且整体上经历近似10次的短期冷暖波动.此外,以上结果与全球范围内全新世气候周期有着较好的一致性,表明我国东部高海拔地区在千年和百年尺度上,对全新世气候振荡同样具有相似的响应.     

气候变化可能触发地震和火山

2009年9月15—17日,地质与地貌灾害的气候作用力研讨会在英国伦敦大学学院（University College London,UCL）召开,会议主要就过去和当前的气候变化与灾难性地质、地貌灾害间的关系进行了探讨。会议讨论内容主要分为三大部分：①过去与未来的气候;     

中昆仑山区封闭湖泊湖面波动及其气候意义

封闭湖泊湖面波动是气候变化很敏感的指示器,其水量平衡特征对此可给予理论证明,进而可将这种灵敏度表示为Z=A_l/A_b=(P_b-E_b)/(E_l—P_l)。中昆仑山区的封闭湖泊自17000a B.P.以来曾经历了三次高湖面,即17000a B.P.前后、12000a B.P.前后及8000—6000a B.P.。其中第一期的高湖面与高山区冰体消融、西风带位置的变动及土壤湿度、太阳辐射值的变化有关,第二次的高湖面是湖泊总体收缩下降过程中出现的相对稳定或短暂回升,第三期的高湖面是全球性温湿气候的产物。理论探讨与实例分析均说明,封闭湖泊湖面波动不仅对无人类观测记录的地质历史时期的气候变化有着重要的指示性,而且可以弥补人类观测资料的不足,是研究气候变化的理想场所。     

全球变暖背景下东亚气候变化的最新情景预测

在最新的SRES A2和B2温室气体排放情景下,利用国际上7个气候模式针对未来全球变暖的数值模拟结果,本文着重分析了东亚区域气候21世纪的变化趋势. 研究揭示：中国大陆年均表面气温升高过程与全球同步,但增幅在东北、西部和华中地区较大,且表现出明显的年际变化;全球年均表面气温增幅纬向上大体呈带状分布,两极地区最为明显,并在北极地区达到最大;此外,21世纪后半段北半球高纬度地区的年平均强升温幅度主要来自于冬季增温. 在21世纪前50年,温室气体含量的增加除在一定程度上会增加青藏高原大部分夏季降水量外,不会对中国大陆其余地区的年、季节平均降水量产生较大影响;但持续的温室气体含量增加将最终导致大陆降水量几乎是全域性的增加.     

Changing river temperatures in northern Germany: trends and drivers of change

Climate change is one of the main drivers of river warming worldwide. However, the response of river temperature to climate change differs with the hydrology and landscape properties, making it difficult to generalize the strength and the direction, of river temperature trends across large spatial scales and various river types. Additionally, there is a lack of long‐term and large‐scale trend studies in Europe as well as globally. In this study, we investigated the long‐term (25 years; 132 sites) and the short‐term (10 years; 475 sites) river temperature trends, patterns and underlying drivers within the period 1985–2010 in seven river basins of Germany. The majority of the sites underwent significant river warming during 1985–2010 (mean warming trend: 0.03 °C year^?1, SE = 0.003), with a faster warming observed during individual decades (1985–1995 and 2000–2010) within this period. Seasonal analyses showed that, while rivers warmed in all seasons, the fastest warming had occurred during summer. Among all the considered hydro‐climatological variables, air temperature change, which is a response to climate forcing, was the main driver of river temperature change because it had the strongest correlation with river temperature, irrespective of the period. Hydrological variables, such as average flow and baseflow, had a considerable influence on river temperature variability rather than on the overall trend direction. However, decreasing flow probably assisted in a faster river temperature increase in summer and in rivers in NE basins (such as the Elbe basin). The North Atlantic Oscillation Index had a greater significant influence on the winter river temperature variability than on the overall variability. Landscape and basin variables, such as altitude, ecoregion and catchment area, induced spatially variable river temperature trends via affecting the thermal sensitivity of rivers, with the rivers in large catchments and in lowland areas being most sensitive. Copyright © 2016 John Wiley & Sons, Ltd.     

中国21kaBP气候模拟的初步试验

本文使用含有陆面过程的９层大气环流谱模式（ＡＧＣＭ＋ＳＳｉＢ）,在地球轨道参数和下垫面边界条件驱动下,对２１ｋａＢＰ的气候进行模拟试验。结果表明,２１ｋａＢＰ时中国东部干旱,西部和青藏高原湿润,全国普遍降温。该模拟结果基本捕捉了由古湖泊资料和孢粉资料重建的气候特征。对模式输出的大气环流场和降水场的分析揭示出,２１ｋａＢＰ东亚夏季风环流明显减弱,而青高原夏季风环流增强;冬季风环流较现在略有增强。该模     

我国小冰期盛期的气候环境

小冰期是距今最近的全球性冷气候事件,是至今研究历史时期气候与人类活动关系的重点时期,它曾对世界和我国的社会经济产生了重要影响. 本文根据我国近年来历史文献、冰芯、树轮、湖芯和石笋的高分辨率研究成果,结合部分国外的结果,对小冰期从高纬、高山地区向中纬、低海拔地区的发展过程,17世纪小冰期盛期大范围普遍的降温、降水变化和空间分布与季风的关系进行了讨论. 该成果和气候模拟的结果可进行检验,为全球增温背景上可能出现的冷波动提供历史相似型.     

2008年和2012年冬季欧洲气候的差异及成因

2008年冬季（1月和2月）和2012年冬季均发生了较强的拉尼娜事件,但欧洲气候,尤其是西欧在这两年差异较大,2008年异常偏暖,而2012年却出现了极寒事件.诊断表明,大气环流异常是造成气候差异的直接原因.2008年冬季,北大西洋上空大气环流异常呈正位相的北大西洋涛动,有利于欧洲异常偏暖;2012年冬季,北大西洋和欧亚高纬阻塞的长期维持是西欧发生极端严寒的重要原因.通过数值试验,研究了前期海表热状况异常对大气的影响.结果表明：北大西洋海温异常能在一定程度上解释这两年欧洲各自的气候异常;尽管热带海温异常对2012年冬季的北大西洋环流形势和欧洲气候异常起一定的贡献,但不能解释2008年的情形;靠近欧洲的北极海冰异常偏少使得欧洲气候偏冷,对2008年的偏暖气候贡献为负,对2012年则有正贡献.     

Impact of climate change on diffuse pollutant fluxes at the watershed scale

This study aims to assess watershed‐scale impacts of changing climate on sediment, phosphorus, nitrogen and pesticide (atrazine) fluxes over the 21st century at the watershed scale. In particular, changes in dissolved and particulate forms of water quality constituents in response to climate change are investigated. The hydrologic model Soil and Water Assessment Tool was calibrated and evaluated in a primarily agricultural watershed in the Midwestern United States to simulate hydrologic and water quality processes on a daily basis over the 2015–2099 time horizon. The model was then driven with 112 distinct statistically downscaled climate projections representing Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (IPCC SRES) low, moderate and high greenhouse gas emission scenarios. Projected hydrologic and water quality responses were categorized according to the three IPCC SRES emission scenarios for summarizing and synthesizing results over early‐century (2015–2034), mid‐century (2045–2064) and late‐century (2080–2099) assessment. Results revealed clear warming trends in the study area, whereas small increases in precipitation were predicted. Streamflow, sediment and total nutrient loads did not differ noticeably between assessment periods. However, the proportion of dissolved to total nutrients increased significantly from early‐century to late‐century periods. With the exception of total atrazine in the mid‐century period, predicted pollutant loads for a given assessment period did not differ between emission pathways for a given assessment period. Changes in pollutant fluxes showed pronounced monthly variability. The projected increase in readily available forms of nutrients has important implications for the ecological health of water systems and management of drinking water supplies. Copyright © 2013 John Wiley & Sons, Ltd.     

Modelling and analysis of the impact of irrigation on local arid climate over northwest China

This study focuses on how irrigation processes affect local climate over arid areas. The chosen study area is northwest China, a typical arid region where three dominant land‐use types are irrigated cropland, grassland, and desert. Observational analysis indicates that the highest precipitation, the coolest surface temperatures, and the slowest warming trend are seen over irrigated cropland from 1979 to 2005. The single column atmospheric model (SCAM), developed by the National Center for Atmospheric Research (NCAR), was used to investigate and better understand the differences in long‐term climate conditions and change over the above three land‐use types. The results indicate that local climate conditions are predominantly controlled by large‐scale forcing in this arid region and that local land surface forcing related to vegetation cover change and irrigation processes also has a significant impact. This study strongly suggests that a realistic climate forecast for this region can be achieved only with both accurate large‐scale and local climate forcing. The irrigated cropland of the region generates stronger evaporation that cools the surface and slows the warming trend more than does the evaporation from the natural grassland and desert. Stronger evaporation also significantly increases precipitation, potentially alleviating the stress of irrigation demands in arid regions. A series of sensitivity SCAM simulations indicate that a drier and warmer climate occurs with decreasing vegetation cover in the irrigated cropland region. Copyright © 2011 John Wiley & Sons, Ltd.     

Possible link between multi-decadal climate cycles and periodic reversals of solar magnetic field polarity

The linkage between multi-decadal climate variability and activity of the sun has been long debated based upon observational evidence from a large number of instrumental and proxy records. It is difficult to evaluate the exact role of each of solar parameters on climate change since instrumentally measured solar related parameters such as Total Solar irradiance (TSI), Ultra Violet (UV), solar wind and Galactic Cosmic Rays (GCRs) fluxes are more or less synchronized and only extend back for several decades. Here we report tree-ring carbon-14 based record of 11-year/22-year solar cycles during the Maunder Minimum (17th century) and the early Medieval Maximum Period (9–10th century) to reconstruct the state of the sun and the flux of incoming GCRs. The result strongly indicates that the influence of solar cycles on climate is persistent beyond the period after instrumental observations were initiated. We find that the actual lengths of solar cycles vary depending on the status of long-term solar activity, and that periodicity of the surface air temperatures are also changing synchronously. Temperature variations over the 22-year cycles seem, in general, to be more significant than those associated with the 11-year cycles and in particular around the grand solar minima such as the Maunder Minimum (1645–1715 AD). The polarity dependence of cooling events found in this study suggests that the GCRs can not be excluded from the possible drivers of decadal to multi-decadal climate change.     

Seasonal climatic effects on the hydrology of a rain garden

This paper evaluates the performance and winter hydrology of two small‐scale rain gardens in a cold climate coastal area in Trondheim, Norway. One rain garden received runoff from a small residential watershed over a 20 month study period while the second rain garden with a shorter study period of 7 months was used as a control. The objective of the study was to investigate the extent to which cold climatic conditions would influence the hydrology and performance of the rain gardens. The hydraulic detention, storm lag time and peak flow reduction were measured and compared seasonally. No significant difference between seasonal lag time could be found, but there was a clear decreasing trend in lag time between rain, rain‐on‐snow and snowmelt. The average peak flow reduction for 44 storms in the study period was 42% compared to 27% for the winter seasons, indicating that the performance of the rain garden is reduced in the cold season (below 0 °C). The average hydraulic detention time for the rain garden was 0·84 ( ± 0·73) with runoff inflow and 1·91 ( ± 3·1) with only precipitation. A strong positive correlation was found between the time since the last wetting event and lag time, and between air temperature and hydraulic detention. This indicates that the time between events and seasonal air temperatures are key parameters in the hydraulic performance of cold climate rain gardens. The rain gardens were not used for snow storage areas, and a volume requirement for this was not evaluated in the study. Copyright © 2007 John Wiley & Sons, Ltd.     

全球12000aBP以来火山爆发记录及对气候变化影响的评估

全新世气候变化的动力成因,至今未有定论．大量地质证据揭示了全新世气候多次降温,并反映出与火山爆发有时问对应关系．现代气候观测证明了火山灰进入平流层滞留后随环流扩散成为太阳辐射的屏障层,从而导致地表降温．停留在地质火山爆发和伞新世气候在逐个点遥相关研究上,难以从宏观机制上加以认识．本文试图对地质火山影响古气候变化的定性推论与现代火山气候效应这两个环节,给予动力机制上的联系和分析．通过火山地质记录的现代气候效应类比,对地质火山数据进行集成,所反映的五次全新世强火山爆发集中期与地质记录的寒冷期／降温期／新冰期能够对应．对火山爆发集中期和平静期两种气候状况,通过三维大气环流模式进行气候数值模拟,评估火山灰产生的不同区域的降温效应．模拟结果表明,火山灰阳伞效应造成北半球年平均温度普遍降低,且具有明显的区域差异．高纬度降温幅度大于低纬度,夏季降温幅度大于冬季．全新世火山影响气候时空记录和火山灰敏感性气候试验为进一步探讨全新世气候变化成因提供重要的科学依据,也为最终认识现代气候系统变化以及对未来十年一百年尺度的气候预测提供重要的参照系．