中国东北地区冬季气温趋势及反相模态分析

利用1951—2010年我国东北地区共97个台站的逐月气温资料,应用trend-EOF和EOF分析方法研究了我国东北地区冬季气温的趋势模态和反相模态及其影响因子。trend-EOF的结果表明,东北地区均为一致型的趋势变化,trend-PC1有明显的年代际周期变化和更长期的上升趋势变化特征。去除全球变暖信号后的EOF分析结果表明:第一模态仍为全区一致型的空间分布,而第二模态的空间分布呈现南北反相型的分布特征,是东北冬季气温变化模态中极为重要的一部分,对应的时间序列有明显的年际周期变化,前两个模态可以解释总方差80%以上的变化。东北地区全区一致的上升趋势是在全球变暖大背景下发生的,既是对全球变暖的局地响应,同时全球变暖也使大气环流发生了变化,西伯利亚高压减弱,纬向环流增强,导致了东北地区冬季气温全区的上升趋势。赤道东太平洋的异常海温对第二模态的出现具有一定的预示意义,当太平洋出现典型的厄尔尼诺年海温距平场分布特征时,东北南部较常年偏暖,北部地区却较常年偏冷。     

中国冬季最低气温观测与再分析资料的比较

运用EOF分解、线性趋势分析、方差分析、小波分析、相关分析等方法,从均值、长期变化、年际和年代际变化特征等方面对NCEP/NCAR(N1T)、NCEP/DOE(N2T)、ERA-Interim(ET)、JRA-25(JT)4种再分析资料集和194站观测资料集中1979—2012年我国冬季最低气温(WTMIN)进行比较。结果表明:(1)ET在再现观测冬季最低气温多年平均时最优;(2)除新疆北部和西南部以及东北北部有降低趋势外,我国大部分地区WTMIN有升高的趋势,N1T对观测温度长期变化趋势再现能力优于其他3种资料;(3)观测WTMIN在中国北方和高原地区年际和年代际变化大于南方地区,四种再分析WTMIN对我国冬季最低气温的年际和年代际变化的再现在不同区域各有所长,总体上以ET为优。(4)再分析资料在再现观测WTMIN年代际时间尺度上的能力相当,以ET最优,尤其是在我国中东部地区和新疆北部地区。N1T和N2T对东北地区观测冬季最低气温年际变化的再现能力较好,ET再现观测WTMIN在1990s之前,2005年之后的3~4 a变化周期特征时能力略优于其他3种资料。     

锡林郭勒盟冬季降水分布特征及成因分析

利用气候相似性原理,按照天气系统影响划分气候区,分析锡林郭勒盟冬季降水分布特征及其成因。冬季降水分布特点与其他季节有所不同,西南部和东部各有一大值区,其原因主要是受河套气旋(倒槽)和蒙古冷涡影响造成,山地小气候也起到重要作用。西部地区70年代降水最多,其他地区降水最多的时期是在90年代,2000年以来降水有所减少,异常偏多或偏少的年份多集中于某个时期,具有一定的周期性。     

Climatological Characteristics of the East Asian Winter Monsoon Simulated by CWRF Regional Climate Model

Based on the ERA-Interim atmospheric reanalysis data from the European Medium-Term Weather Forecast Center from 1979 to 2016 and the ERSSTv4 sea surface temperature data from the US National Oceanic and Atmospheric Administration, the regional climate model CWRF was used to simulate the climate characteristics in East Asia. The results show that the CWRF model can well reproduce the average characteristics of the East Asian winter monsoon circulation, including the location and intensity of the low-level continental cold high pressure and variation characteristics of wind field in high and low levels. The occurrence area and frequency of the north wind in the simulation and the reanalysis data were further calculated and compared. It is shown that they are basically consistent. The distribution of air temperature and precipitation over China are well represented by the model. The water vapor transport is also in good agreement with the reanalysis data. The water vapor from the Bay of Bengal plays a vital role in the precipitation over South China. The simulation results of apparent heat source and apparent moisture sink show that the model can well simulate the thermal difference between the East Asian continent and the adjacent sea area. The analysis results indicate that CWRF model has the ability to simulate the main characteristics of the East Asian winter monsoon.     

中国冰雪旅游研究：内涵辨析、脉络梳理与体系构建

推动冰雪旅游高质量发展践行了“冰天雪地也是金山银山”发展理念,助推着体育强国、健康中国建设,满足了人民日益增长的美好生活需要。中国冰雪旅游历经三十多年的发展,已形成规模化、整体化发展格局;北京冬奥会的筹办更是给冰雪旅游带来重大发展契机,利好政策陆续出台,消费热情不断高涨。与此同时,冰雪旅游相关研究也持续涌现,取得了丰厚研究成果。文章以“内涵辨析-脉络梳理-体系构建”为逻辑主线,从冰雪旅游基础概念、发展脉络演进、研究内容、研究方法及区域等方面对中国冰雪旅游展开分析和评述。研究表明：冰雪旅游内涵丰富,学者们从资源、动机以及季候等视角展开了概念界定;冰雪旅游研究历经4个阶段,研究与实践联系日益紧密,产业发展受资源、政策、市场等因素驱动;研究内容已形成一定体系,与国家、产业发展战略的结合有待加强;以定性研究为主,缺乏定量、纵深研究;研究区域高度集中在东北、华北地区,且视角较为宏观。最后提出从理论构建及研究视角、研究内容、研究方法、区域等方面进行未来研究的创新。以期推动中国冰雪旅游研究的理论化和体系构建,引领和指导未来冰雪旅游领域研究,推进中国后冬奥时代冰雪旅游高质量发展。     

中国东部地区冬季气温与北极涛动的关系

利用NCEP/NCAR再分析资料、北极涛动（AO）指数序列及中国160个台站月温度资料,分析1951-2007年中国冬季气温与AO指数的变化特征及其相互关系。结果表明：1951-2007年AO与中国东部地区冬季气温基本呈正相关关系。中国东部地区冬季气温指数（IWT）与北极涛动指数（IAO）均逐渐增强,并有显著的年际和年代际变化,均存在准18 a的周期变化特征。从偏相关系数来看,在年际尺度上,西伯利亚高压对中国东部地区冬季气温的年际变化影响较大,而AO与冬季气温无显著相关关系;在年代际尺度上,AO对中国东部地区冬季气温的影响较显著,比西伯利亚高压影响大。东亚大槽偏弱时,中国冬季气温偏高,AO指数也偏高,反之则相反。在年际尺度上,东亚大槽对中国东部地区冬季气温的年际变化影响较大,而AO与冬季气温无显著相关关系;在年代际尺度上,AO和东亚大槽对中国冬季气温的变化影响均较显著。     

更新世以来南海表层水温变化及其古气候意义

南海南部2Ma以来古温度记录显示该海域更新世以来海水表层温度的不断降低,并且以冰期降低为特征,间冰期温度变化不大。南海南北经向表层海水温差的大小,反映了东亚冬季风的强弱变化,2 Ma以来的温差变化说明东亚冬季风在中更新世之前的持续强化,中更新世之后不断减弱,而在晚第四纪时又再次转为增强,同时叠加在长期变化趋势之上的是轨道时间尺度上冰期增强间冰期减弱的循环波动。青藏高原构造作用可能对中更新世时期东亚冬季风强化产生重要影响,而更新世以来东亚冬季风变化的整体趋势及轨道尺度变化主要受全球冰量变化和低纬ENSO影响。     

晚第四纪中国北方沙地风沙沉积的Zr/Rb比值特征及意义

Zr/Rb比值因不受后期成壤作用影响,在黄土高原黄土堆积中可作为较好的冬季风气候替代性指标。与黄土沉积相比,中国北方沙地的气候变化研究相对较弱,能够敏感反映沙地气候变化的替代性指标仍处于探索阶段。本文选取东亚季风控制区的毛乌素沙地、浑善达克沙地和科尔沁沙地11个典型的风成沉积序列,对Zr/Rb比值及其意义进行了研究。通过全岩样品Zr、Rb元素含量、Zr/Rb比值与平均粒径和>63 μm的粗颗粒百分含量对比分析,发现在毛乌素沙地,Zr/Rb比值与粗颗粒百分含量和平均粒径成正相关关系,与黄土高原的变化趋势相似,可作为冬季风强度的替代性指标。而在浑善达克沙地和科尔沁沙地,虽然Rb含量在砂质古土壤层中随着细颗粒物质的增加而增大,与毛乌素沙地的变化相同;但是,Zr含量也表现出增加趋势,导致Zr/Rb比值变化趋势与毛乌素沙地相反。其主要原因可能是沙地所处的构造地貌单元不同,物源区存在差异。因此,Zr/Rb比值作为冬季风的替代性指标在不同沙地应用需要慎重分析。     

Elements’ Geochemical Characteristics of PM10 and PM2.5 in Beijing During Winter and Spring

From 2012 to 2013, heavy haze frequently hit Beijing in spring and winter. The fine atmospheric particulates can be inhaled by people, and remain in the respiratory tract and lung for quite a long time. The heavy metal elements in the particles are harmful, and even carcinogenic to human bodies. Therefore, it is necessary to master the geochemical characteristics and the temporal and spatial distribution of the heavy metal elements in atmospheric particles. The atmospheric particulates (TSP/PM₁₀/PM_2.5) were collected by using TH1500C intelligent medium volume (80~120 L/min) air samplers in the five functional areas and suburbs of Beijing, respectively in January 2013 (heating period) and April 2013 (non-heating period). The five functional areas were: building materials factory area, residential area, education area, business area and recreation area, each functional area having three sampling sites, and five in suburbs. The sampling height was 1.5 m above the ground and the distance of the sampling sites to roads exceeded 50 m so as to avoid excessive impact of vehicle exhaust emissions. These samples were analyzed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), Inductively Coupled Plasma Optical Emission Spectrometer(ICP-OES)and Atomic Fluorescence Spectrometer (AFS), by which 21 elements including Al, Fe, Mn, As, Hg, Cd, Cr were tested. Based on the comparisons of the concentration and element content variation of atmospheric particulates of these functional areas in and after the heating period, the spatial distribution of atmospheric particulates and the influence of coal combustion on the concentration and composition of atmospheric particulates were revealed. The elements sources of atmospheric particulates were also discussed by computing the enrichment factor of the elements, providing a scientific basis for the air contaminant treatment in Beijing. The results showed that the total concentration of the 21 elements of PM₁₀ and PM_2.5 in the functional areas of Beijing in winter was higher than that in spring, the most marked among them being the business area. In winter, the concentration of pollution elements in the building materials factory area and the business area in Beijing was extremely high, and the residential area, education area, recreation area and suburbs where people live were much better, among which the education area was the best. The concentration change of particulates in suburbs was quite smaller in winter and spring than that of the urban area. It also showed that the concentrations of Cd, Cr, As and Hg in PM₁₀ increased by 233%,306%,298%,141%,respectively and the increase in PM_2.5 was 442%、309%、310%、256%, respectively. These abovementioned elements show a tendency to accumulate mainly in PM_2.5 whose concentrations in winter were significantly higher than those in spring. It indicates that coal heating during winter makes great contributions to the polluting elements in atmosphere and the main polluting particulates are Cd, As and Hg.     

中国园林叠山的传承与发展——北京奥林匹克森林公园叠山之探讨

我国造园叠石世家“山石韩”已传承百余年,其第四代传承人韩建中创办了北京南山石韩园林绿化工程有限公司并完成了北京奥林匹克森林公园“林泉高致”和“天境”两大主要假山景观工程的设计与施工。本文介绍了这两处假山景观的设计立意和营造技巧,从实例出发体现出我国园林叠山的传承与发展。