树木年轮所标志的气候演变过程的动力学特征

对华山地区1544-1989年共446年的5-6月降雨量代用资料树木年轮非线性系统时间序列进行 了动力系统特征的分析。结果表明,代用资料树轮时间序列是非线性系统的混沌时间序列,混沌吸引子在时滞参数 为9,嵌入维数为3的重构向量空间中恰好打开。其Kolmogorov熵为0．032,表明华山地区现在5-6月降雨量的 大小对将来5-6月的降雨量有一定影响。Hurst指数为0．555 6,说明华山地区5-6月降水量时间序列的突变性 不强,即该时间序列具有持久性。

气候－森林响应过程敏感性的初步研究──以四川西部紫果云杉群落为例

本文以我国西部特有树种之一，紫果云杉（Ｐｉｃｅａｐｕｒｐｕｒｅａ）为例，采用林窗模型（ＦＯＲＥＣ），初步探讨了气候对森林群落的组成结构及生物量的影响。敏感性分析表明：（１）林窗模型对紫果云杉的林分结构以及演替过程的模拟与实际状况基本吻合；（２）森林群落对气候变化的响应是十分敏感的，并主要体现在气候基准和变率两个特征指标上。

从硬能力到软能力:中国应对气候变化能力建设的政治学思考——基于政策过程的视角

国家应对气候变化的软能力在气候治理中具有一种"退隐"却巨大的能动作用。从政策过程理论来看,中国应对气候变化软能力建设的困境在于制度性推动力不足,可能导致政策过程滞缓,影响政策供给能力;政策方案的竞争机制不健全,缺乏完善的利益协商妥协机制;社会利益表达不均衡以及参与结构的封闭趋势,导致强势集团对国家利益和社会利益的双重侵蚀。破解中国应对气候变化软能力建设困境的政治学思路,在于增强应对气候变化及节能减排政策过程的制度性推动力,保障政策流程的制度化、规范化、稳定化;健全政策方案的竞争机制和利益协商妥协机制,促进各种利益主体在民主法治的轨道上竞争,防范竞争失序;加大应对气候变化及节能减排政策参与结构的开放程度,通过建立均衡的低成本的利益表达机制,降低政策协商的门槛。

大气科学专业开设《陆面过程与气候》课程的必要性和可行性分析

随着与气候变化问题相关的教学和研究工作的日益活跃,要求大气科学专业对学生知识结构的培养更加多元化。其中陆面过程与气候变化相关学科内容近年来蓬勃发展且已具有一定的理论基础,但是大气科学本科专业尚没有针对该学科分支的专门课程。本文从必要性和可行性等方面,探讨了在大气科学本科专业开设《陆面过程与气候》的可能。同时对课程的内容设置、课程教学方式等方面进行了讨论。

三江平原气候突变分析

采用累积距平法、Jy参数法和Mann-Kendall法联合检测1955～2000年三江平原气候变化过程中的突变现象,讨论了引发三江平原气候突变的可能原因。分析发现,三江平原年降水量在20世纪60年代发生了减少突变;而三江平原在20世纪70年代和80年代连续两次经历的增温突变,使其气温变化与东北北部平原其它地区明显不同;年日照时数和平均风速的减少突变均发生在20世纪80年代。总体来看,三江平原气候变化在20世纪80年代最明显。

辽南黄土晚更新世粒度敏感组分的古环境意义

选取大连市金州区北部华农村一处高度为14.5 m的黄土剖面为研究对象,进行高密度采样获得714个样品并进行粒度测试,运用粒径-标准偏差法和端元模型法提取粒度敏感组分并对其进行分析,与深海氧同位素MIS气候阶段进行对比,重建了晚更新世以来辽南地区的环境变化过程.结果表明:①端元组分EM1、EM2、EM3、EM4分别代表低空环流短距离的沉积物、西伯利亚控制下的尘暴组分、冰期出露的黄渤海陆架平原以及周围河流沉积物,充分说明了辽南黄土沉积物源的复杂性.②气候阶段Ⅰ(12.26~14.45 m)、阶段Ⅱ(6.55~12.26 m)、阶段Ⅲ(2.3~6.58 m)、阶段Ⅳ(0~2.3 m)分别对应深海氧同位素气候阶段MIS5、MIS4、MIS3、MIS2,经历了较长的温暖湿润期、较短的寒冷干燥期、相对较弱的暖期和明显的干冷时期4个气候阶段.

河流地貌演化研究进展

本文基于近年来全球河流地貌演化的研究实例及新进展,介绍了主要的研究载体与思路,讨论了河流地貌演化事件背后的地质、环境意义。沉积学、地貌学、物源分析、低温热年代学等是解决河流地貌演化问题的重要工具。沉积学记录着河流演化的一手资料,同时,沉积物定年技术的发展为揭示河流演化过程提供了高精度的时间约束。地貌指数研究是根据河流剖面形态与流域特征等揭示河流及区域地貌演化过程的研究手段,在恢复基岩隆升历史,定义地貌演化状态和判断分水岭迁移等方面具有优势。基于碎屑热年代学的物源分析方法结合沉积物沉积年代测定的研究思路则是利用了地表物质的“源-汇”过程变化,是揭示水系沟通演化历史的有效手段。当借助中-低温热年代学的多方法联合和单矿物的多重定年作为物源示踪剂时,可以有效提高分析精度,具有广阔的研究前景。另外,低温热年代学和宇宙核素10Be等对浅表过程十分敏感,记录了百万年-千年尺度的河流侵蚀作用,是示踪流域侵蚀方式空间变化和定量化揭示侵蚀过程的有力工具。河流的诞生与演化是地表过程的重大事件,记录了局部或区域的构造-气候背景,也是研究构造-气候-地貌耦合及互馈过程的重要纽带。特别是新生代晚期以来,地貌形成过程伴随着古人类的诞生与发展,而河流的演化则在古人类活动和迁徙中起到了重要的控制作用。因此,河流地貌演化的背景动力及环境意义体现了地球多圈层的相互作用与协同演化。

构造地貌学：构造-气候-地表过程相互作用的交叉研究

构造地貌学是发展迅速的新兴交叉学科.与传统地貌学不同,构造地貌学是一种定量地貌学,强调对地貌过程的定量描述,其核心概念是构造-气候-地表过程相互作用,聚焦于以量化的方式具体阐述构造活跃造山带地区气候、地形、水文、物理和化学剥蚀、沉积以及岩石变形之间的相互作用.本文首先阐释构造地貌学的主要科学问题与核心概念,即构造、气候和地表过程之间的相互作用.随后简要介绍构造地貌学的主要研究方法和手段,特别是对学科发展起到重要推动作用的测年手段(如宇宙成因核素和低温热年代学)和空间探测技术手段(如LiDAR).基于近年来构造地貌学的研究实例,梳理了构造-气候-地表过程相互作用的研究中获得的一些重要认知,这些研究实例涵盖的时空尺度巨大:时间跨度从数小时到百万年,空间跨度从单个断裂到整个造山带.这些跨度广泛的研究对理解造山带的地形演化具有重大的启示意义.最后,简要总结了构造地貌学的前沿问题.

Key Issues on Cryospheric Changes,Trends and Their Impacts

On the basis of analyzing the importance of cryospheric researches in China and current status of cryospheric sciences in the world, this paper addresses key issues and main contents of present cryospheric sciences in China. The key issues currently addressed are： i） mechanisms of different types of glaciers in response to climate change and the scale-conversion in water resources assessments; ii） modeling of water and heat exchanges between frozen soil and vegetation; iii） parameterization of physical processes in cryosphere as well as coupling with climate models. To gain full clarification of these key issues, works of the following three aspects should be highlighted, i.e., cryospheric processes and responses to climate change, influences of cryospheric changes, and adaptation strategies for cryospheric changes.

Origin of Red Color of the Lower Siwalik Palaeosols:A Micromorphological Approach

Palaeosols associated with fluvial of the Siwalik Group are and lacustrine deposits that occur as thick multiple pedocomplexes. The bright red color of the palaeosol beds has been earlier interpreted as a result of hot and arid palaeoclimate. However, as against this view, our investigations of the bright red palaeosol beds of the Lower Siwaliks suggest that the climate was cool and subhumid, instead of hot and arid during the deposition of these beds. Since cold climate is not very conducive to impart red coloration, further research is needed to explain the cause of these red beds. For this, the micromorphological study of soil thin sections was done which showed the presence of features such as dissolution and recrystallisation of quartz, feldspar and mica, compaction, slickensides, presence of calcite spars, subrounded and cracked nature of quartz grains, microfabric, complex patterns of birefringence fabrics, pigmentary ferric oxides, thick cutans and cementation by calcite. These features indicate that diagenesis took place on a large scale in these sediments. The positive Eh and neutral-alkaline pH of soils also suggest that the conditions were favorable for the formation of diagenetic red beds. During burial diagenesis of sediments, the hydroxides of ferromagnesian minerals got converted into ferric oxide minerals （hematite）. During deep burial diagenesis smectite was converted into illite and the preponderance of illite over smectite with increasing depth of burial also indicates the diagenesis of sediments. Thus, the red color of the Lower Siwalik palaeosols seems to be due mainly to the burial diagenesis of sediments and does not appear to be due to the then prevailing climatic condition.

The Two Main Mechanisms of Glacier Lake Outburst Flood in Tibet,China

With the global warming,the disasters of Glacier Lake Outburst Flood(GLOF) have taken place frequently in Tibet in recent years and attracted more and more attention.A systematic survey was conducted on the 19 GLOFs in Tibet to study their two main mechanisms.Investigations indicated that all the events occurred in end-moraine lakes,and the outburst occurred partially and instantly.And the breach had the shape of an arc or a trapezoid in overflow outburst and its top width was 3-5 times more than the height.The two main mechanisms of GLOFs in Tibetan end-moraine Lake were overflow and piping,and the overflow mechanism caused by iceberg collapse was dominated in most cases.A formula was proposed to calculate the critical thickness of iceberg tongue that determines the collapse.Granular analysis of the moraine materials revealed that seepage deformation is crucial in the outburst process.Finally,we conducted a case study of the Guangxiecuo Lake to show its possible process of outburst and estimated the peak discharge of the resulted flood.

Rainfall and Tillage Impacts on Soil Erosion of Sloping Cropland with Subtropical Monsoon Climate- A Case Study in Hilly Purple Soil area, China

Under global warming, storm events tend to intensify, particularly in monsoon-affected regions. As an important agricultural area in China, the purple soil region in the Sichuan Basin, where it has a prevailing monsoon climate, is threatened by serious soil erosion. Tillage operations alter runoff and soil erosion processes on croplands by changing the physical properties of the soil surface. To clarify the relationship between tillage and soil erosion in the purple soil region, three different tillage practices in this region were investigated at the plot scale over 4 years： bare land with minimum tillage （BL）, conventional tillage （CT） and seasonal no-tillage ridges （SNTR） which was initially designed to prevent soil erosion by contoured ridges and no-tillage techniques. The results showed that although there were no significant differences in the surface runoff and soil erosion among the three oractices, BL caused relatively high surface runoff and soil erosion, followed by CT and SNTR. Classification and comparison of the rainfall events based on cluster analysis （CA） verified that the surface runoff was not significantly different between most intensive event and long intensive events but was significantly different between most intensive and short and medium-duration events. Only the rainfall events with the highest rainfall intensity could trigger serious soil erosion, up to 1000 kg ha^-1 in the region. Further detailed investigations on the effects of tillage operations on the soil erosion in a subtropical region with a monsoon climate are needed to provide a basis for modeling catchments and designing better management practices.

Implications of Climate Change on Streamflow of a Snow-Fed River System of the Northwest Himalaya

Air temperature and snow cover variability are sensitive indicators of climate change. This study was undertaken to forecast and quantify the potential streamflow response to climate change in the Jhelum River basin. The implications of air temperature trends （＋0.11℃decade） reported for the entire north-west Himalaya for past century and the regional warming （＋0.7℃/decade） trends of three observatories analyzed between last two decades were used for future projection of snow cover depletion and stream flow. The streamflow was simulated and validated for the year 2007-2008 using snowmelt runoff model （SRM） based on in-situ temperature and precipitation with remotely sensed snow cover area. The simulation was repeated using higher values of temperature and modified snow cover depletion curves according to the assumed future climate. Early snow cover depletion was observed in the basin in response to warmer climate. The results show that with the increase in air temperature, streamfiow pattern of Jhelum will be severely affected. Significant redistribution of streamflow was observed in both the scenarios. Higher discharge was observed during spring-summer months due to early snowmelt contribution with water deficit during monsoon months. Discharge increased by 5%-40% during the months of March to May in 2030 and 2050. The magnitude of impact of air temperature is higher in the scenario-2 based on regional warming. The inferences pertaining to change in future streamflow pattern can facilitate long term decisions and planning concerning hydro-power potential, waterresource management and flood hazard mapping in the region.

Key regions where land surface processes shape the East Asian climate

Land-atmosphere interaction,as one of the key processes affecting the atmosphere and climate over East Asia,has drawn increasing attention during the past few decades.However,the current level of understanding regarding the mechanisms through which land surface processes impact the East Asian climate needs to be improved.Based on existing studies,six key regions where land surface processes affect the East Asian climate are proposed in this study,which can provide a valuable reference for future research into land-atmosphere interaction in East Asia.

Carbon Dioxide Capture Using Gas Hydrate Technology

According to IPCC （Intergovemmental Panel on Climate Change） Fourth Report, carbon dioxide emissions from the combustion of fossil fuels have been identified as the major contributor to global warming and climate change. One of the new approaches for capturing carbon dioxide and subsequently lowering the emissions is based on gas hydrate crystallization. Gas hydrates have a large capacity for the storage of gases which also resemble an attractive method for gas filtration. The basis of the separation is the selective partition of the target component between the hydrate phase and the gaseous phase. It is expected that carbon dioxide is preferentially encaged into the hydrate crystal phase compared to the other components. In the present paper, after a comparison of gas hydrates with existing capture technologies, a novel apparatus for gas hydrate production is illustrated and results of a first set of experimental applications of the reactor for CO2 hydrate formation and separation are presented. In particular, the effects of two different promoters were investigated. Results show that the reactor allows a good level of temperature control, resulting in rapid hydrate formation and mild operating conditions. Results are a basis for setting up a procedure for CO2 separation and capture.

Shrinking and Drying up of Baiyangdian Lake Wetland:A Natural or Human Cause?

The shrinking and drying up of wetlands in arid and semiarid areas of China have been widely observed in the recent years, but there has been no consensus on whether the aggravation is caused by human activities or by global climate warming. For a better understanding of the cause, this study investigates the dynamic changes of Baiyangdian Lake wetland over the last 40 years. It is shown that since the 1980s, Baiyangdian Lake has suffered from an insufficient water input and shrunk considerably. By using SPSS 11.0, this study urines a detailed Analysis on the signifficance of the effects of the possible driving factors for the degradation. It is identified that the North China Plain has been warrnin~ up significantly in recent years, which causes a significant reduction in the precipitation and inflow to the lake. Although human disturbances such as the irrigation and storage of water in reservoirs do not play a decisive role, they accelerate the degradation and their effects should be minimized.

Responses of Hydrological Processes to Climate Change in the Zhujiang River Basin in the 21st Century

In this study, discharge at the outlet of Xijiang River, the biggest sub-basin of the Zhujiang River, was simulated and projected from 1961 to 2099 using the hydrological model HBV-D. The model uses precipitation and temperature data from CISRO/MK3 5, MPI/ECHAM5, and NCAR/CCSM3 under three greenhouse gas emission scenarios (SRES A2, A1B, B1). The results in water resources and flood frequency suggest that annual precipitation and annual runoff would increase after 2050 relative to the reference period of 1961-1990. In addition, increasing trends have been projected in area averaged monthly precipitation and runoff from May to October, while decreasing trends in those from December to February. More often and larger floods would occur in future. Potential increase in runoff during the low-flow season could ease the pressure of water demand until 2030, but the increase in runoff in the high-flow season, with more often and larger floods, more pressure on flood control after 2050 is expected.

Study of the Influence of Critical Radius on the Cloud Drops Formation in the Seeding Operations

In the seeding operations in order to mitigate the climatic changes or to intervene beneficently on the precipitations process, it is very important to know the roll of the critical radius size of the cloud drops formation and its posterior evolution. In the seeding operations programs, the fundament is to determinate the critical radius in order to obtain efficient results. So, it must consider （a） the critical radius size necessary in order to get the better results; （b） the atmospheric conditions that determine it. In order to get a methodology to calculate the critical radius in each atmospheric condition, the present work has been developed. And with them, it can estimate the nuclei size necessary in order to assure good seeding. The authors had obtained approximate values that were good enough to the goals.

Development of a Cooling System for Geothermal Borehole Probes

The high potential of geothermal energy in quantity and availability can be a great option, facing the huge problem of growing energy use linked with the climatic problems. Therefore, it is necessary to reduce costs and risks for the use of geothermal energy sources. Because most of the problems have to do with insufficient knowledge about the conditions in the earth crust, the key to take root of geothermal energy is widespread research. The cooling system allows the use of all needed devices in deep boreholes without strict time or temperature limitations, which promotes the achieving of comprehensive information. To develop the purpose-built components among conducting experiments about the thermodynamic processes, a prototype is provided step by step.

Teaching Sustainability in Design without Greenwashing

Teaching design incorporating a sense of sustainability to architecture students is a challenge today, primarily because of the trend to label every design as sustainable or green even though it is no different from a more traditional one. The result is a ＂green-washed＂ education in architecture. To address this issue, this paper describes a teaching methodology of architectural design with a special focus on sustainability implemented in the Graduate School of Architecture in Clemson. This method includes an analysis of the location, the climate conditions, the materials needed and the construction process. Knowing that sustainable design is generally perceived as being expensive, there is a special focus on simplicity and affordability. Rather than relying on expensive technical solutions, students are encouraged to design for the given environment and apply passive strategies. In the approach discussed in this paper, the design process is a number of logical scientific decisions rather than an intuitive draft. The goal of this pedagogy is to raise awareness about how to handle global resources carefully and to show the importance of the later performance of the project as a key to design. The teaching strategy is described here along with the successful participation by our graduate students in a number of refereed competitions.