Geochemistry of the Jinman Vein—Type Copper Deposit,Western Yunnan Province,China——I.Element Geochemical Characteristics

The Jinman copper deposit,which is situated on the northern margin of the Lanping-Simao back-arc basin,western Yunnan Province,is a silver-bearing,high-grade vein-type copper deposit.Comprehensive element geochemical studies of the host rocks and hydrothermal minerals revealed the regularities in the distribution,mobilization and transport of elements from the host rocks to hydrothermal minerals.In conjunction with the fluid inclusion and isotope data,it is suggested that the ore-forming fluid was derived mainly from a deep source characterized by CO2 enrichment and reduction in nature.It is also suggested that the oreforming materials come largely from a deep source.although the contribution of the country rocks should not be ruled out.It is also found that some hydrothermal minerals are possessed of MREE-enrichment patterns.It is deduced that the REEs in the deep-source ore fluid were transported in the form of CO3^2- complexes and were deposited in a continental basin(or a hot-spring basin).     

不同时间尺度上的热带海气耦合扰动

本文从热带地球流体运动的物理特征出发,建立了适合热带地区特点的海气耦合模式方程组并对之进行了系统的尺度分析,指出时间尺度不同的运动其受控的物理过程各异。基于这种时间尺度的差异,我们有可能将不同时间尺度的运动分开来研究。计算结果表明,去掉海洋中的波动过程,仅仅考虑与海洋表面温度场的变化相联系的扰动形式会对耦合系统及耦合扰动的性质造成很大影响。由此看来,Ｎｅｅｌｉｎ所谓的“快波极限”不是一种好的近似。     

Reductions of PM<Subscript>2.5</Subscript> in Beijing-Tianjin-Hebei urban agglomerations during the 2008 Olympic Games

The Atmospheric Environmental Monitoring Network successfully undertook the task of monitoring the atmospheric quality of Beijing and its surrounding area during the 2008 Olympics.The results of this monitoring show that high concentrations of PM2.5 pollution exhibited a regional pattern during the monitoring period(1 June-30 October 2008).The PM2.5 mass concentrations were 53 μg m 3,66 μg m 3,and 82 μg m 3 at the background site,in Beijing,and in the Beijing-Tianjin-Hebei urban agglomerations,respectively.The PM2.5 levels were lowest during the 2008 Olympic Games(8-24 August):35 μg m 3 at the background site,42 μg m 3 in Beijing and 57 μg m 3 in the region.These levels represent decreases of 49%,48%,and 56%,respectively,compared to the prophase mean concentration before the Olympic Games.Emission control measures contributed 62%-82% of the declines observed in Beijing,and meteorological conditions represented 18%-38%.The concentration of fine particles met the goals set for a "Green Olympics."     

东亚冬季风异常与广东前汛期旱涝关系的初步分析

利用500hPa北半球格点资料,参照历史平均东亚大槽位置,定义了东亚冬季风强度指数(I₅₀₀)。分析发现,近50年东亚冬季风强度有减弱趋势,特别是1987年以来冬季风明显减弱。根据广东48个站1954～2004年前汛期(4～6月)降水资料,用区域旱涝指数W对广东前汛期旱涝等级进行划分。51年内广东有9年前汛期出现大涝(或特涝),11年出现大旱(或特旱),旱涝发生频繁。冬季风异常对广东前汛期降水的影响比较大,强冬季风年后广东前汛期出现大旱的可能性较大,而出现大涝的可能性很小。     

The 2020/21 Extremely Cold Winter in China Influenced by the Synergistic Effect of La Niña and Warm Arctic

In the first half of winter 2020/21,China has experienced an extremely cold period across both northern and southern regions,with record-breaking low temperatures set in many stations of China.Meanwhile,a moderate La Ni?a event which exceeded both oceanic and atmospheric thresholds began in August 2020 and in a few months developed into its mature phase,just prior to the 2020/21 winter.In this report,the mid?high-latitude large-scale atmospheric circulation anomalies in the Northern Hemisphere,which were forced by the negative phase of Arctic Oscillation,a strengthened Siberian High,an intensified Ural High and a deepened East Asian Trough,are considered to be the direct reason for the frequent cold surges in winter 2020/21.At the same time,the synergistic effect of the warm Arctic and the cold tropical Pacific(La Ni?a)provided an indispensable background,at a hemispheric scale,to intensify the atmospheric circulation anomalies in middle-to-high latitudes.In the end,a most recent La Ni?a prediction is provided and the on-coming evolution of climate is discussed for the remaining part of the 2020/21 winter for the purpose of future decision-making and early warning.     

拜登政府气候行政指令解析及应对策略探讨

2021年1月20日,民主党人拜登宣誓就任美国第46届总统,上任第一天就签署行政指令重新加入《巴黎协定》.根据《巴黎协定》要求,美国于递交国家批准函30天后,也就是2021年2月19日正式重新加入《巴黎协定》,实现美国气候政治转向.拜登政府的气候政策尚未完全清晰,但其发布的"国内国际应对气候危机行政指令"[1]可以为分...     

全球升温1.5℃和2.0℃背景下北京市暴雨洪涝淹没风险研究

基于第五次耦合模式比较计划(CMIP5)的5个气候模式模拟结果,结合FloodArea模型,对RCP8.5情景下全球升温1.5℃和2.0℃时,北京市极端降水和淹没风险进行分析。结果表明：北京市极端降水量呈从西南向东北逐渐减少的分布趋势。在升温2.0℃时,极端降水和淹没风险增加较升温1.5℃时明显,郊区极端降水增加最明显的地区是房山和门头沟,城区极端降水量增加最明显的地区是海淀、石景山和丰台区。海淀区出现一级和二级淹没风险的面积最大,其次是丰台和石景山区。郊区的延庆和怀柔是发生一级淹没风险面积最大的地区。     

切变线降水系统微物理特征及隆水机制个例分析

利用机载云粒子探测系统(PMS).对2004年7月1日影响吉林省的一次切变线降水过程进行了探测飞行,利用所获取的宏微观资料对此次降水过程的微物理结构、降水机制进行综合分析.结果表明:此次切变线降水云系主要由高层云、雨层云、碎云构成,高层云和雨层云中间夹有1100m左右的无云区;3类云中平均云滴浓度、平均云滴直径各不相同;云水含量随高度分布不均匀,云的不同部位云水含量起伏较大;冰晶浓度平均为17.3个/L;此次探测的降水云系符合Bergeron提出的催化云一供水云相互作用导致降水的概念.根据云图及其他探测资料综合分析,冰晶主要产生于高层云上部或卷层云的冰晶播撒,供水云为高层云中下部和雨层云.     

X 波段双极化雷达对云中水凝物粒子的相态识别

人工影响天气研究需对云中降水粒子的相态和分布结构进行准确识别,以便提高人工影响天气作业效率.中国科学院大气物理研究所的车载X波段双极化雷达可提供与云中降水粒子大小、形状、相态等特征密切相关的4个极化参数:反射率因子、差分反射率、差分相移率、水平和垂直极化相关系数.利用这4个极化参数加上环境温度作为5个输入参量,建立了降水粒子相态模糊逻辑识别算法,识别的降水粒子有10种:毛毛雨、雨、湿霰、干霰、小雹、大雹、雨加雹、湿雪、干雪、冰晶.利用此雷达的实际观测资料,并与地面和飞机空中实测资料对照,对我国南、北方地区观测的降水天气过程进行分析,结果表明:建立的模糊逻辑算法对云内水凝物粒子的相态识别分类合理.     

INFLUENCE OF THE SURFACE AIR TEMPERATURE OVER ASIAN-PACIFIC REGION ON THE SUMMERTIME NORTHEASTERN ASIAN BLOCKING HIGH*

Synthesis analysis and singular value decomposition (SVD) methods were used to study the impact of surface air temperature (SAT) over Asian-Pacific region on the summertime northeastern Asian blocking high (NABH) with NCEP/NCAR Reanalysis Data.The results showed that 500 hPa geopotential height and SAT fields over Asian-Pacific region shared the similar pattern of East Asian Pacific (EAP) wave train;there was steady remote response relationship between the EAP wave train in summer and the "+-+" pattern of tropical SAT in zonal direction from former winter to summer;there were two relative negative(positive) Walker circulations over the tropical Indian Ocean and Pacific when being more(less) summertime NABH. The influence of sea surface temperature anomaly (SSTA) on the summertime NABH was possibly as follows.The special distribution of SSTA in tropical zonal direction continuously forced the tropical convection and zonal circulation from former winter to summer,and led them to act anomaly.Finally the abnormal conditions were transported to middle-high latitudes through EAP wave train and yielded the advantageous or disadvantageous atmospheric circulation background for the summertime NABH.