极地大气科学与全球变化研究进展

南极和北极是地球上的气候敏感地区, 也是多个国际科学计划研究全球气候变化的关键地区。极地大气科学考察与研究是极地科学研究的重要组成部分。中国气象科学研究院的极地大气科学考察与研究始于20世纪80年代, 25年来有较大进展。中国气象科学研究院参加了我国组织的23次南极考察、2次北冰洋考察和3次北极考察; 承担了南极长城站和中山站、北极黄河站气象业务建设和维持, 以及中-澳合作南极冰盖3个无人自动气象站工作; 进行了常规地面气象、Brewer大气臭氧、近地面物理、冰雪和大气化学等观测, 获得了较为系统的极地大气环境资料。开展了有关极地大气科学与全球变化的研究, 在极地天气气候特征及气候变化时空多样性、极地海冰变化和南极海冰涛动、极地近地面物理特征和海-冰-气相互作用、中山站臭氧变化特征及南极臭氧洞和大气化学、气候代用资料获取和古气候环境以及极地大气环境变化对东亚环流和中国天气气候影响等方面的研究取得了新进展。中国极地大气科学正积极通过多学科交叉、走国际合作道路, 努力提高对极地在全球变化中作用的认识水平, 并积极探索极地变化对我国气候、环境的影响。     

“96·8”华北暴雨数值模拟与稳定性分析

分析1996年8月发生在华北地区的台风暴雨过程的环流形势,发现：副热带高压与台风低压之间的气压梯度很大,宽广的偏南急流源源不断地向北输送水汽和能量,而太行山一带正处于汇合区,构成十分有利的暴雨天气形势。应用MM5数值预报方法对1996年8月4—5日的降雨天气过程进行数值模拟,并依据天气学原理和位涡理论对此过程的稳定性进行分析认为：（1）MM5数值预报模式较好地模拟出了台风暴雨的物理过程。（2）此次降雨的不稳定层结有南高北低现象,同时有对称不稳定和对流不稳定存在;条件性对称不稳定可使环流加速,对降水有一定的增幅作用。     

Experimental observation on the characteristics of the near-surface turbulence over the Antarctic ice sheets during the polar day period

Based on the ultrasonic anemometer/thermometer data in the East Antarctic coastal area ice sheets ob-tained first by Chinese scientists, turbulent intensity, kinetic energy and sensible heat of turbulence, surface roughness height drag coefficient and normalized variation were calculated and analysed using the eddy-correlation method. The results show that the values of roughness height and drag coefficient are 4.3 X 10 m and 1.8x 10 -³, respectively. These turbulent parameters have apparent diurnal variations. Project supported by the National Natural Science Foundation of China (Grant No. 49675252).     

地理信息系统及在地震科学中的应用简介

首先介绍了地理信息系统的定义,然后ａｐＩｎｆｏ４．０解释了地理信息系统中涉及的一些重要概念;对ＭａｐＩｎｆｏ４．０的图形编辑功能和数据库操作进行了扼要的说明。最后简单介绍了地理信息系统在地震科学中的应用,着重分析了ＭａｐＩｎｆｏ４．０在地震活动性分析中的应用前景。     

Detrimental effects of reduced seawater pH on the early development of the Pacific abalone

The hatching process of the Pacific abalone Haliotis discus hannai was prolonged at a pH of 7.6 and pH 7.3, and the embryonic developmental success was reduced. The hatching rate at pH 7.3 was significantly (10.8%) lower than that of the control (pH 8.2). The malformation rates at pH 7.9 and pH 8.2 were less than 20% but were 53.8% and 77.3% at pH 7.6 and pH 7.3, respectively. When newly hatched larvae were incubated for 48 h at pH 7.3, only 2.7% of the larvae settled, while more than 70% of the larvae completed settlement in the other three pH treatments. However, most 24 h old larvae could complete metamorphosis in all four pH treatments. Overall, a 0.3-unit reduction in water pH will produce no negative effect on the early development of the Pacific abalone, but further reduction in pH to the values predicted for seawater by the end of this century will have strong detrimental effects.     

Inertial gravity wave parameters for the lower stratosphere from radiosonde data over China

Characterization of gravity wave(GW)parameters for the stratosphere is critical for global atmospheric circulation models.These parameters are mainly determined from measurements.Here,we investigate variation in inertial GW activity with season and latitude in the lower stratosphere(18-25 km)over China,using radiosonde data with a high vertical resolution over a 2-year period.Eight radiosonde stations were selected across China,with a latitudinal range of 22°-49°N.Analyses show that the GW energy in the lower stratosphere over China has obvious seasonal variation and a meridional distribution,similar to other regions of the globe.The GW energy is highest in winter,and lowest in summer;it decreases with increasing latitude.Velocity perturbations with longitude and latitude are almost the same,indicating that GW energy is horizontally isotropic.Typically,85%of the vertical wavelength distribution is concentrated between elevations of 1 and 3 km,with a mean value of 2 km;it is almost constant with latitude.Over 80%of all the horizontal wavelengths occur in the range 100-800 km,with a mean value of 450km;they show a weak decrease with increasing latitude,yielding a difference of about 40 km over the 22°-49°N range.The ratio of horizontal wavelength over vertical wavelength is about 200:1,which implies that inertial GWs in the lower stratosphere propagate along nearly horizontal planes.Ratios of their intrinsic frequency to the Coriolis parameter decrease with increasing latitude;most values are between 1 and 2,with a mean value of 1.5.Study of the propagation directions of GW energy shows that upward fractions account for over 60%at all stations.In contrast,the horizontal propagation direction is significantly anisotropic,and is mainly along prevailing wind directions;this anisotropy weakens with increasing latitude.     

Snowdrift effect on snow deposition: Insights from a comparison of a snow pit profile and meteorological observations in east Antarctica

A high-frequency and precise ultrasonic sounder was used to monitor precipitated/deposited and drift snow events over a 3-year period(17 January 2005 to 4 January 2008) at the Eagle automatic weather station site,inland Antarctica.Ion species and oxygen isotope ratios were also generated from a snow pit below the sensor.These accumulation and snowdrift events were used to examine the synchronism with seasonal variations of δ~(18)O and ion species,providing an opportunity to assess the snowdrift effect in typical Antarctic inland conditions.There were up to 1-year differences for this 3-year-long snow pit between the traditional dating method and ultrasonic records.This difference implies that in areas with low accumulation or high wind,the snowdrift effect can induce abnormal disturbances on snow deposition.The snowdrift effect should be seriously taken into account for high-resolution dating of ice cores and estimation of surface mass balance,especially when the morphology of most Antarctic inland areas is similar to that of the Eagle site.     

淮河流域焦岗湖水质参数时空变化及影响因素

焦岗湖是淮河左岸一个天然湖泊,集防洪、灌溉、养殖、旅游等多种功能于一体.利用焦岗湖4个季节水质监测数据,运用Kriging方法,分析焦岗湖水质参数的时空变化及影响因素.结果表明:由于受水文季节变化过程及人类活动等综合影响,焦岗湖水质参数在时间及空间上均存在一定差异.从时间变化来看,夏季透明度较低、秋季较高;溶解氧浓度在春、冬季显著高于夏、秋季;总氮、总磷浓度与高锰酸盐指数均表现为夏季最高、秋季最低.从空间变化来看,4个季节的透明度空间差异较为显著;溶解氧浓度在春、冬季空间分布较为均匀,夏季呈现中心高周围低的变化趋势,秋季则表现为西高东低;总磷浓度春季分布较为均匀,夏、秋及冬季则呈西高东低之势;高锰酸盐指数在春、秋季节呈现东高西低之势,夏季高浓度主要集中在湖区北部,冬季浓度变化不大.     

Influencing domain of peripheral sources in the urban heavy pollution process of Beijing

Multiple cities in a diveloped economic area may consist of a city cluster,and the difusion and mixing of its pollutants result in the effect of pollutants plume between cities and the large-scale regional pollution diffusion phenomenon.The distant transfer and diffusion of pollutants occurs when massive aerosols are affected by the dynamic porcess of large-scale circulations.Research suggesten that the life span of aerosol particles whose diameters are about 1 um is the longest.The longevity …