热带气旋形成的多尺度组合理论——流体动力学实验模拟与合成分析的结合

结合流体动力学实验模拟(物理模型)与大量记录的合成分析,本文提出了热带气旋形成的多尺度组合理论。它强调了热带中尺度深厚对流云系的作用,同时它也着重说明了大尺度环境气流与小尺度积云对流的重要作用。 本理论可解释一些有关热带气旋以前所不能解释的观测事实,特别是它解释了热带气旋前期低压环流的形成。     

利用雷达进行风暴的识别,跟踪,分析和临近预报的方法

介绍了以体积扫描的天气雷达资料为基础而建立的一种对雷暴的实时自动识别、跟踪和短时预报的方法，重点介绍该方法的一些基本概念，文中“风暴”被定义为其反射率和大小超过临界值的一邻接区域，用这种方式定义的风暴可以离散的观测时间间隔的资料来识别。按照某些几何逻辑关系去处理风暴的合并与分裂，用一种最优化方案使某一时刻的风暴与以后时刻的风暴相配对，风暴位置和大小的短时预报采用了对风暴路径历史资料进行加权线性拟合     

Comparison of manual and automatic methods for measurement of methane emission from rice paddy fields

The methane emission flux from rice paddies was simultaneously measured with automatic and manual methods in the suburban of Suzhou. Both methods were based on the static chamber/ GC-FID techniques. Detail analysis of the experimental results indicates: a) The data of methane emission measured with the automatic method is reliable. b) About 11 or 19 o’clock of local time is recommended as the optimum sampling time for the manual spot measurement of methane emission from rice paddies. The methane emission fluxes measured by manual sampling at local time other than the optimum time have to be corrected. The correction coefficient may be determined by automatic and continuous measurement. c) In order to get a more accurate result, an empirical correction factor, such as 18%, is recommended to correct the seasonally total amount of measured methane emission by enlarging the au-tomatically measured data or reducing the manually measured ones.     

Wintertime Cyclone Activity and Its Relation to Precipitation over China

The authors examined the variability in wintertime cyclone activity and storm tracks and their relation to precipitation over China for the period 1951–2006 using the observational data.Two apparent modes of variability were assumed for the cyclone activity and storm tracks.The first mode describes the oscillation in the strength of the storm tracks in East Asia,which significantly increased since the mid-1980s,whereas the second mode describes a seesaw oscillation in the storm track strength between the Central-Southeast China and northern East Asia.The storm tracks over the Central-Southeast China have increased since the late 1960s.The possible causes for the variation of the cyclone activity and storm tracks are also explored.It is shown that wintertime precipitation,which has increased since the mid-1980s,concentrates in Central-Southeast China.The enhancement may be caused by the first mode of variability of storm tracks,whereas the interannual variability of precipitation may be linked to the second mode of the storm track variability.     

同步轨道相对论电子通量长期倒空事件的统计研究

地球辐射带中有"杀手"电子之称的相对论电子通量增强和损失过程一直是空间物理学和空间天气学研究的热点.本文通过对2000—2016年间,地球同步轨道相对论电子通量降低至背景通量水平并持续时间长达3天以上这一特殊现象进行了相关统计研究.从事件的时间分布角度,本文研究了约1.5个太阳活动周内共62例事件随太阳活动水平高低的分布情况,结果表明:在太阳活动周下降期有较少的事件发生,而在峰年、谷年这类事件的发生率与太阳活动水平的高低并没有直接联系.随后,我们对这62例事件在开始、持续、结束三个阶段分别做了一些相关参数的统计,探讨相对论电子通量长期倒空事件的客观规律和产生机制.研究结果表明:事件发生前,太阳风动压、密度的显著增加引起磁层顶向内收缩,等离子体层顶一直维持在高L区域,IMF B_z分量南向和磁暴过程使相对论电子通量通过绝热和非绝热等物理损失机制降至背景通量水平.当这些相对论电子达到背景通量水平后,较弱的太阳风条件和地磁活动水平不足以提供充分的可以使相对论电子通量增长的源;虽然有些相对论电子通量长期倒空事件期间存在中、小磁暴过程,但这些强度较弱的磁暴很可能不会显著地影响...     

Argo floats revealing bimodality of large-scale mid-depth circulation in the North Atlantic

Analysis of Argo float trajectories at 1 000 m and temperature at 950 m in the North Atlantic between November 2003 and January 2005 demonstrates the existence of two different circulation modes with fast transition between them. Each mode has a pair of cyclonic - anticyclonic gyres. The difference is the location of the cyclonic gyre. The cyclonic gyre stretches from southeast to northwest in the first mode and from the southwest to the northeast in the second mode. The observed modes strongly affect the heat and salt transport in the North Atlantic. In particular, the second mode slows down the westward transport of the warm and saline water from the Mediterranean Sea.     

Predicting June Mean Rainfall in the Middle/Lower Yangtze River Basin

We demonstrate that there is significant skill in the GloSea5 operational seasonal forecasting system for predicting June mean rainfall in the middle/lower Yangtze River basin up to four months in advance. Much of the rainfall in this region during June is contributed by the mei-yu rain band. We find that similar skill exists for predicting the East Asian summer monsoon index(EASMI) on monthly time scales, and that the latter could be used as a proxy to predict the regional rainfall. However, th...     

The 13th and 14th Workshops on Antarctic Meteorology and Climate

<正>1.Overview In July 2018, the Antarctic community came together to meet at the 13th Workshop on Antarctic Meteorology and Climate (WAMC) in Madison, Wisconsin, USA (Fig. 1); and in the following year in June 2019, the 14th WAMC was held in     

Undiscovered Phanerozoic Porphyry Copper Deposits—A Global Assessment

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