The Hindcast of Winter and Spring Arctic and Antarctic Oscillation with the Coupled Climate Models

This study evaluates the ability of the global coupled climate models in hindcasting the Arctic Oscillation (AO) and Antarctic Oscillation (AAO). The results show that the models can well simulate the spatial distribution of AO with better results in winter than in spring. In the troposphere in spring, the simulation of AO on the whole is still relatively good with a comparatively high correlation with the NCEP/NCAR reanalysis. The models can also well reproduce the spatial distribution of AAO throughout the year at all levels of the troposphere, and the spatial simulation is better at 850 hPa than at the surface. Although the simulation is better in winter than in other seasons, the seasonal variation is not so significant and the differences among different models are relatively small. In addition, the capability of the models for “predicting” the AO and the AAO index time series is limited, because only a few models can capture their observed interannual variability at the 95% significance level.     

The hindcast of winter and spring Arctic and Antarctic Oscillation with the coupied climate models

研究评估了耦合气候模式对冬、春季北极涛动(AO)和南极涛动(AAO)的预测效能.结果表明,模式对于北极涛动和南极涛动的模拟能力都是比较强的,其中,对冬季的模拟能力要强于春季.冬季,几乎所有的模式都能很好地模拟出对流层内北极涛动的空间分布形态特点,空间相关系数很高.春季,大部分模式的模拟结果仍然是比较好,与再分析资料结果的空间相关性比较高.对于南极涛动,模式在全年对流层各个层次上都能比较好地刻画其空间分布,且模式在850 hPa等压面上的空间模拟效能要稍强于海平面.相对来说,冬季的模拟效果也稍强于其他季节,但是,差异不显著,模式与模式的差别也比较小.另外,模式对于北极涛动和南极涛动的时间序列模拟能力有限,时间序列相关系数只有少数几个模式达到显著性水平.     

2008年云南省秋季连阴雨天气的环流及水汽特征分析

对云南省2008年10月24～11月6日严重连阴雨天气的环流和水汽特征进行分析.结果表明:本次连阴雨过程是在副热带高压强度较强、位置偏西、槽前西南气流和副高外围西南气流都有利于水汽向云南输送的环流背景下,中低层受槽前西南气流、低空急流和切变线的影响下产生的.在整个连阴雨期间对流层低层都有充足的水汽,连阴雨前期水汽来源于孟加拉湾和南海2个通道的汇合,而连阴雨后期水汽主要来源于南海.整个连阴雨期间云南全省或大部均处于水汽辐合区内,区域性强降雨出现在水汽通量散度<-32×10-7g·(hPa·s)-1·cm-2的区域.     

基于力反馈手柄的移动载人月球车操作控制系统

移动载人月球车相关技术的研究是我国未来载人登月探测的重要任务.根据载人月球车的需求,本文从航天员操作舒适度和操作工作空间出发,设计了一种面向载人月球车操作的力反馈手柄,在具体的场景设计下可以带给航天员力触觉感受,辅助航天员进行安全、有效的驾驶行为.基于力反馈手柄的移动载人月球车操作控制系统包含力反馈手柄、硬件系统、软件系统.力反馈手柄主要由二自由度旋转机构、手杆、带光编码器的直流电机组成;硬件系统为STM32单片机及相关接口电路,STM32作为下位机接收来自上位机的指令信号和力反馈信息,并且向上位机反馈手柄位置信息;为完成移动载人月球车操作控制系统的仿真测试,软件系统是基于unity3D所开发的月球车驾驶场景,搭载使用虚拟传感器,做出驾驶行为决策解算出相应的力反馈信息.实验结果表明,力反馈手柄能较好地辅助航天员操纵载人月球车,有效提升了载人月球车的驾驶效率和安全性.     

5·12汶川地震青川县木鱼镇滑坡坝稳定性分析

滑坡坝及其形成的堰塞湖是山区常见的一种地质灾害,在强地震发生时,滑坡坝形成的堰塞湖的数量多,规模大.汶川5·12地震发生时,就形成了多个堰塞湖,这些滑坡坝一旦发生溃坝,将会对下游灾民和抢险人员生命安全构成很大的威胁.文中对汶川大地震发生期间木鱼镇滑坡坝进行研究.通过地质分析和计算表明,这个滑坡坝在发生和强降雨和地震期间是稳定的,不会对下游构成威胁,因此,可以不对此滑坡坝采取防治措施.此研究结果已在实践中证明是正确的,其研究方法可以为类似工作提供参考.     

Estimation of sampling error uncertainties in observed surface air temperature change in China

This study examines the sampling error uncertainties in the monthly surface air temperature (SAT) change in China over recent decades, focusing on the uncertainties of gridded data, national averages, and linear trends. Results indicate that large sampling error variances appear at the station-sparse area of northern and western China with the maximum value exceeding 2.0 K² while small sampling error variances are found at the station-dense area of southern and eastern China with most grid values being less than 0.05 K². In general, the negative temperature existed in each month prior to the 1980s, and a warming in temperature began thereafter, which accelerated in the early and mid-1990s. The increasing trend in the SAT series was observed for each month of the year with the largest temperature increase and highest uncertainty of 0.51 ± 0.29 K (10 year)⁻¹ occurring in February and the weakest trend and smallest uncertainty of 0.13 ± 0.07 K (10 year)⁻¹ in August. The sampling error uncertainties in the national average annual mean SAT series are not sufficiently large to alter the conclusion of the persistent warming in China. In addition, the sampling error uncertainties in the SAT series show a clear variation compared with other uncertainty estimation methods, which is a plausible reason for the inconsistent variations between our estimate and other studies during this period.

     

Preface to the Special Issue on the “Forecast and Evaluation of Meteorological Disasters”(FEMD)

<正>Meteorological disasters usually exert huge impacts on the development of both human society and the economy.According to statistics from the United Nations International Strategy for Disaster Reduction,the annual mean economic loss caused by meteorological disasters accounts for 3%–6% of the total amount of global GDP.China is a country that has been     

PROPAGATION OF INTERNAL INERTIO-GRAVITY WAVE SPECTRA IN VERTICAL WIND SHEAR ENVIRONMENTS*

The variation of the spectral structure of the internal inertio-gravity waves (ⅡGWs) propagating in the atmospheric wind shear environments is discussed in this paper.From the hydrodynamic equation set in Boussinesq approximation,a spectral propagation equation ⅡGWs satisfy is derived,then the spectral correspondence in the upper atmosphere is numerically calculated,after a forced spectrum is given as a Van-Zandt one at the lower boundary.The results show that if ⅡGWs do not encounter the critical-layer absorption,then their spectral structure may be not changed significantly; otherwise it may be changed greatly,and a few of spectral components are filtered.Also the isotropy of the assumed VanZandt spectrum is distorted in upward-propagating process.That is the directional filtering effect of the atmospheric wind on the gravity wave spectrum.