1961-2008年中国西南地区极端气候变化幅度的海拔效应(英文)

A total of 12 indices of temperature extremes and 11 indices of precipitation ex-tremes at 111 stations in southwestern China at altitudes of 285-4700 m were examined for the period 1961-2008. Significant correlations of temperature extremes and elevation in-cluded the trends of diurnal temperature range, frost days, ice days, cold night frequency and cold day frequency. Regional trends of growing season length, warm night frequency, coldest night and warmest night displayed a statistically significant positive correlation with altitude. These characteristics indicated the obvious warming with altitude. For precipitation extreme indices, only the trends of consecutive dry days, consecutive wet days, wet day precipitation and the number of heavy precipitation days had significant correlations with increasing alti-tude owing to the complex influence of atmospheric circulation. It also indicated the increased precipitation mainly at higher altitude areas, whereas the increase of extreme precipitation events mainly at lowers altitude. In addition, the clearly local influences are also crucial on climate extremes. The analysis revealed an enhanced sensitivity of climate extremes to ele-vation in southwestern China in the context of recent warming.     

新冠疫情期间武汉樱花的情感效应

运用大数据文本挖掘和分析工具,对比新冠疫情期间武汉和非武汉地区居民所发布的微文,探究了武汉樱花在不同居民群体间情感效应的作用机制,研究发现：1）本地居民樱花微文的关注点多而分散,非本地居民的关注点少而集中;2）武汉樱花对不同地区居民情感的影响与疫情发展状况紧密相关;3）武汉樱花在疫情期间对武汉居民具有情感支持效应,对非武汉地区居民具有情感凝聚效应;4）疫情改变人的情感和景观解读背景,并赋予景观新的意义,新的景观意义反作用于居民,构成情感闭合回路。最后提出建议,抗疫恢复工作应多关注居民心理层面的缺失,从居民与城市、景观的情感关系入手,向武汉居民传达城市美好生活理念。     

Physicochemistry and Mineralogy of Storm Dust and Dust Sediment in Northern China

Dust sediments collected from 1995 to 1998 in Beijing, Dunhuang, Inner Mongolia, Kashi, the Kunlun Mountains, Lanzhou, Ningxia, the Taklimakan Desert, and Xi‘an, China, were characterized in terms of their physical, chemical, and mineralogical properties. Most aerosols and dust analysed ranged in texture from silty clay to clay loam. Their median particle diameters (Mds) generally ranged between 5 to 63μm,coinciding with those of loess from central China and the finest sand from northwestern China. The dust sediments were characterized by a predominance of SiO2 and Al2O3, followed by K2O. Their SiO2/Al2O3and K2O/SiO2 molar ratios ranged from 5.17 to 8.43 and from 0.009 to 0.0368, respectively. The mass concentration spectrum during a dust storm showed a single peak, rather than the triple peak generally observed under clear sky conditions. The dominant minerals were chlorite, illite, calcite, and dolomite.These physical, chemical, and mineralogical properties were consistent with those of aeolian soils and loess in western and central China. The results suggest that aerosols and fine-gained fractions of dust sediments collected in northern China are mainly composed of soil material transported from the arid and semiarid regions of China and Mongolia by prevailing winds. The rate of deposition and properties of dust falling on eastern China were strongly influenced by meteorological conditions, season, latitude, longitude, and altitude of the sampling sites.     

近800 ka以来南大洋区域经向海表温度差异及气候变化响应

南大洋地理位置关键,其海水热量变化往往会对区域或全球气候产生影响。通过对比南大西洋和南太平洋等南大洋关键海域近800 ka以来的海水表层温度（Sea Surface Temperature,简称SST）变化,同时结合南极冰芯记录的大气CO2浓度、大气温度及大洋底栖氧同位素等气候演变替代指标,对南大洋区域经向海表热量差异及气候响应进行分析,结果显示：1）南大洋不同海域近800 ka以来SST的演化具有明显的区域性。如相较于其他冰期,南大西洋ODP1090站SST值在MIS 12~10期的最低值出现约3.8℃的上升,南塔斯曼海ODP1170站SST冰期最低值则出现约1.3℃的下降;而西南印度洋的MD962077站SST冰期最低值在MIS 10期之后出现约2.2℃的上升。此外,滤波分析结果显示3个站位对"中更新世气候转型"（Mid-Pleistocene Transition,简称MPT）等全球性事件均响应明显;2）"中布容事件"（Mid-Brunhes Event,简称MBE）的发生对南大洋经向温度差异（ΔSST1090-1170）影响明显：MBE之前,ODP1090站位SST在冰期-间冰期旋回中的平均值或极值均比ODP1170站SST的平均值或极值低,但MBE发生期间及之后的MIS 5、MIS 2、MIS 1期,ODP1090站SST的平均值或极值均比ODP1170站SST的平均值或极值高。同时,南大洋经向SST差异（ΔSST1090-1170）在间冰期对气候变化的响应明显比冰期显著。显然,气候变化条件下的海洋锋面迁移及Agulhas流阶段性增强导致外部向南大西洋输入热量有所增加,最终使ΔSST1090-1170值偏正。因此,冰期-间冰期旋回中气候环境改变导致的海洋锋面移动幅度差异等是影响环南极海域经向温度差异变化的关键因素之一。     

基于时间序列法的北京市需水量预报(英文)

It is essential to establish the water resources exploitation and utilization planning,which is mainly based on recognizing and forecasting the water consumed structure rationally and scientifically.During the past 30 years(1980-2009),mean annual precipitation and total water resource of Beijing have decreased by 6.89% and 31.37% compared with those perennial values,respectively,while total water consumption during the same period reached pinnacle historically.Accordingly,it is of great significance for the harmony between socio-economic development and environmental development.Based on analyzing total water consumption,agricultural,industrial,domestic and environmental water consumption,and evolution of water consumed structure,further driving forces of evolution of total water consumption and water consumed structure are revealed systematically.Prediction and discussion are achieved for evolution of total water consumption,water consumed structure,and supply-demand situation of water resource in the near future of Beijing using Time Series Forecasting Method.The purpose of the endeavor of this paper is to provide scientific basis for the harmonious development between socio-economy and water resources,for the establishment of rational strategic planning of water resources,and for the social sustainable development of Beijing with scientific bases.     

哈罗铁路沿线沉积物粒度特征

哈罗铁路开通对沿线资源的开发具有重要意义,然而自开通以来饱受风沙危害.对铁路沿线及防沙体系内沉积物粒度特征参数进行了对比分析,以期为该线风沙危害的科学防治提供有益参考.结果表明:(1)铁路沿线沉积物组成以中细沙为主,灌丛沙地分选性中等至很差,偏度以近对称为主,峰度中等至很窄;戈壁区沉积物整体分选性较差,偏度以极正偏为主...     

树轮稳定同位素记录:进展、问题及展望

树轮稳定同位素比率(δ13 C、δ18O 和δD)变化与树木生长季的气候和环境条件密切相关。控制实验表明, 树轮稳定同位素比率变化可较好地记录树木叶片气孔活动、水分来源、水分利用效率等相关信息, 已成为古气候和全球变化生态学研究的重要代用指标和手段之一。树轮稳定同位素记录能够较好地保留低频气候环境变化信息, 与年轮宽度相结合, 可有效地进行区域古气候重建和全球变化生态学方面的研究。文章综述了树轮稳定同位素的分馏机理及其发展, 系统阐述和评价了利用树轮稳定同位素指标进行古气候和古环境的相关研究成果, 并指出树轮稳定同位素研究在中国未来亟须着重发展的方向。     

Automatic mapping of lunar landforms using DEM-derived geomorphometric parameters

Developing approaches to automate the analysis of the massive amounts of data sent back from the Moon will generate significant benefits for the field of lunar geomorphology. In this paper, we outline an automated method for mapping lunar landforms that is based on digital terrain analysis. An iterative self-organizing (ISO) cluster unsupervised classification enables the automatic mapping of landforms via a series of input raster bands that utilize six geomorphometric parameters. These parameters divide landforms into a number of spatially extended, topographically homogeneous segments that exhibit similar terrain attributes and neighborhood properties. To illustrate the applicability of our approach, we apply it to three representative test sites on the Moon, automatically presenting our results as a thematic landform map. We also quantitatively evaluated this approach using a series of confusion matrices, achieving overall accuracies as high as 83.34% and Kappa coefficients (K) as high as 0.77. An immediate version of our algorithm can also be applied for automatically mapping large-scale lunar landforms and for the quantitative comparison of lunar surface morphologies.     

滇东北山原县域土地分级与土地分类──以会泽县为例

将滇东北山原内会泽县土地按复合土地系统、土地系统、土地单元三级,划分为6个复合土地系统、20个土地系统和128个土地单元,分析了复合土地系统的自然特征.     

南极半岛周边海域表层沉积物粒度分布特征及其环境指示意义

基于南极半岛周边海域表层沉积物调查以及收集的资料,并通过分析表层沉积物粒度数据研究沉积物类型和分布特征,探讨沉积物的变化规律。南极半岛周边海域的沉积物类型比较丰富,主要分为四大类:砾质、砂质、粉砂质以及泥质沉积物;根据不同的水深和地貌单元可分为陆架(或岛架)碎屑沉积物、陆坡(或岛坡)沉积物和深海沉积物。研究区沉积物属于冰海沉积物,并可划分为残副冰碛物和混合副冰碛物。沉积物的搬运介质以冰川、冰筏为主,海流对沉积物的影响较为明显,沉积物类型随地形变化而呈有规律的分布。