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Evidence of wintertime CO_2 emission from snow-covered grounds in high latitudes

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Science China Earth Sciences 1999年第4期42卷 378-382页

作者：方精云唐艳鸿KOIZUMI Hiroshi(Division of Plant Ecology National Institute of Agro-Environmental Sciences Tsukuba 305 Japan)BEKKU Yukiko(National Polar Institute Tokyo 192 Japan)

In order to measure C02 flux in wintertime arctic ecosystems, C02 gas was sampled from various snow-covered grounds by using a closed chamber method during the First China Arctic Scientific Expedition from March to May in 1995. The C02 gas samples were measured by using an infra-red analyzer (IRGA) . The results showed that (i) C02 emission was detected from all kinds of the snow-covered grounds, which provides direct evidence that the arctic tundra is functioning as a source of atmospheric C02; (ii) C02 release was also detected from the permanent ice profile and icecap, and (iii) C02 evolution from terrestrial ecosystems in higher latitudes increased with an increase of surface temperature in accordance with the exponential function. This indicates a close coincidence with that under normal temperature conditions, and provides a useful method for predicting change in C02 flux in the arctic ecosystems with the global climate change.

关键词： arctic CO2 emission high latitudes icecap.

POSSIBLE IMPACTS OF MADDEN–JULIAN OSCILLATION ON THE SEVERE RAIN-SNOW WEATHER IN CHINA DURING NOVEMBER 2009

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Journal of Tropical Meteorology 2013年第3期19卷 233-241页

作者：贾小龙梁潇云 National Climate Center

Possible relationships between MJO and the severe rain-snow weather in Eastern China during November of 2009 are analyzed and results show that a strong MJO process is one of the strong impact *** is very active over the Indian Ocean in November ***,it maintains 9 days in MJO phase 3,just corresponding to the two strongest rain-snow *** of MJO events show that when the MJO convective center is located over the Indian Ocean,the probability of rainfall is significantly increased and the temperature is lower than normal in eastern China,which is consistent with the situation in November of *** circulation anomalies of mid-and higher-latitudes can be influenced by the tropical MJO convection forcing and this influence could be realized by *** the MJO is over the Indian Ocean,it is favorable for the maintenance of a circulation pattern of two ridges versus one trough at mid-and ***,the western Pacific subtropical high is stronger and more westward than normal,and a significant convective belt appears over eastern East *** these circulation anomalies shown in the composite result also appeared in the observations in November 2009,which indicates the general features of relationships between the MJO and the circulation anomalies over the *** the zonal circulation anomalies,the MJO convection can also lead to meridional circulation *** the MJO convection is located over the Indian Ocean,the western Pacific is dominated by anomalous descending motion,and the eastern East Asia is controlled by strong convergence and ascending ***,an anomalous meridional circulation is formed between the tropics and middle latitudes,enhancing the northward transportation of low-level *** is potentially helpful to understanding and even forecasting such kind of rain-snow weather anomalies as that in November 2009 using MJO.

关键词： MJO rain-snow weather Indian Ocean tropics middle-high latitudes

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中低纬度变化磁场的分析(英文)

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天文研究与技术 1989年第S1期 283-296页

作者：徐文耀张满莲林云芳曾小苹中国科学院地球物理研究所国家地震局地球物理研究所

地球变化磁场呈现复杂时空特点,这是由引起该磁场的磁层一电离层电流以及地球内部感应电流的特性决定的。为了研究变化磁场的物理成因及其在日地物理事件中的特性。首先必须将组成变化磁场的各种成分分离开来,然后逐一加以研究。我们... 详细信息

地球变化磁场呈现复杂时空特点,这是由引起该磁场的磁层一电离层电流以及地球内部感应电流的特性决定的。为了研究变化磁场的物理成因及其在日地物理事件中的特性。首先必须将组成变化磁场的各种成分分离开来,然后逐一加以研究。我们采用自然正交分量法对我国八个地磁台站的时均值序列进行了分析,这些台站展布在27°12′48″到49°36′的中低纬度带内,正是Sq电流体系焦点所在的纬度带。分析结果表明,由发电机过程产生的Sq电流体系是这一纬度带主要的电流体系,与磁暴环电流有关的扰动电流体系也是十分重要的电流体系,在冬季月份,它往往超过Sq程度。此外与UT有关的磁扰变化也被明显地分离出来,它的成因可能与地球磁场的偏心结构有关。这些成份的相对大小随季节变化,而且有确定的纬度分布。我们提出了一套单台分析和多台分析的方法。考虑到自然正交分量法收效快,稳定性好,所需资料列序列短的特点,这种方法可以推广到台站使用。自然正交分量法可以从成因上分离不同成因,使它在理论研究中具有优于一般付氏分析、时序迭加等方法,可为中低纬电流系成因研究提供有用的结果。

关键词： Variable Magnetic Fields Middle and Low latitudes MNOC