Arc／Info—Grid模块及其水文模型应用

利用地理信息系统可以建立流域的数字高程模型,并与grid模块的水文表面分析工具结合,形成直观的流域环境三维显示,再通过计算、统计与分析,即可获取精确的水文因子数据,为进一步水文定量研究及应用提出了一种高效的方法。     

基于地理信息系统的太阳直接辐射与冰川物质平衡的关系

基于冰川微地形对冰川物质平衡重要影响的认识,在考虑朝向、坡度、地形遮蔽等因素的条件下,以地理信息系统为手段,对乌鲁木齐河源１号冰川冰面太阳可能直接辐射进行了理论计算．在此基础上,建立了计算冰面任意一点物质平衡的Ｂ＝ｆ（Ｔ,Ｒ）（气温－辐射）模型．比较了该模型与Ｂ＝ｆ（Ｔ）（气温）模型、Ｂ＝ｆ（Ｐ,Ｔ）（降水－气温）模型及Ｂ＝ｆ（Ｑ）（能量平衡）模型之间的优缺点,表明该模型具有物理意义明确、计算精度较高、参数易于获得等优点,从而为计算冰川物质平衡提供了新的途径．     

Relationship between global seismicity and solar activities

The relations between sunspot numbers and earthquakes (M≧6), solar 10.7 cm radio flux and earthquakes, solar proton events and earthquakes have been analyzed in this paper. It has been found that: (1) Earthquakes occur frequently around the minimum years of solar activity. Generally, the earthquake activities are relatively less during the peak value years of solar activity, some say, around the period when magnetic polarity in the solar polar regions is reversed. (2) the earthquake frequency in the minimum period of solar activity is closely related to the maximum annual means of sunspot numbers, the maximum annual means of solar 10.7 cm radio flux and solar proton events of a whole solar cycle, and the relation between earthquake and solar proton events is closer than others. (3) As judged by above interrelationship, the period from 1995 to 1997 will be the years while earthquake activities are frequent. In the paper, the simple physical discussion has been carried out. These results supported the exploration and studies of some researchers to a certain extent. This work is supported by Foundation of the Chinese Academy of Sciences (major item).     

Ca, Al-rich inclusions in Yamato 791717 (CO3) carbonaceous chondrite: Formation and alteration

In three polished thin sections of Yamato 791717 (CO3). fifty-five Ca, Al-rich inclusions were found, which include two hibonite-bearing, eight melilite-rich and forty-five spinel-pyroxene inclusions. Based on the petrography and mineral chemistry of the inclusions, it is proposed that the melilite-rich inclusions and spinel-pyroxene inclusions condensed in the solar nebula, and the hibonite-bearing inclusions crystallized from melts. The heavy alteration of the inclusions in Yamato 791717, which probably took place under a very oxidizing condition in the solar nebular, is also confirmed. Project supported by the National Natural Science Foundation of China (Grant No. 49673200). and by the Japanese Society for Promotion of Sciences (JSPS).     

SSBUV and NOAA-11 SBUV/2 Solar Variability Measurements

The Shuttle SBUV (SSBUV) and NOAA-11 SBUV/2 instruments measured solar spectral UV irradiance during the maximum and declining phase of solar cycle 22. The SSBUV data accurately represent the absolute solar UV irradiance between 200–405 nm, and also show the long-term variations during eight flights between October 1989 and January 1996. These data have been used to correct long-term sensitivity changes in the NOAA-11 SBUV/2 data, which provide a near-daily record of solar UV variations over the 170–400 nm region between December 1988 and October 1994. The NOAA-11 data demonstrate the evolution of short-term solar UV activity during solar cycle 22.     

东海陆架全新统高分辨率层序地层学研究

在高分辨率１４Ｃ测年、岩石、生物、化学、同位素、气候及磁性地层学研究成果基础上,通过不同沉积背景典型钻孔的沉积学分析,运用层序地层学理论,对东海陆架全新统进行了高分辨率层序划分及对比;建立了全新世层序地层格架及海平面变化过程;提出了相应的层序成因模式。研究结果表明,东海陆架全新统相当于一个发育中的六级（１～１０ｋａ）层序,可进一步划分为３个七级（０．１～１ｋａ）层序和若干个更次级层序。代表１个六级或３个七级周期相对海平面变化过程中叠加有若干更次级的海平面波动,它们与地球旋回谱系中的太阳带、历法带密切相关。七级层序具有与三级层序相近的内部构型和成因格架。在东海陆架全新世沉积演化过程中,长江三角州至少有３次不同程度地越过东海陆架进入冲绳海槽,并滞留有至少３层海侵改造“残积砂”沉积。在东海陆架全新世海平面变化期间,最大海平面时期为约距今６～５ｋａ,大致高于现今海平面２～４ｍ,最低海平面在距今１０ｋａ左右,大约低于现今海平面１３０ｍ。目前,由于温室效应的影响,海平面仍呈小幅度波浪式上升。事实证明,层序地层学不仅丰富了现代海洋沉积学的内容,而且解决了许多海洋沉积学未能解决的问题。     

Non-linear spherical Alfvén waves

We present a one-dimensional numerical study of Alfvén waves propagating along a radial magnetic field. Neglecting losses, any spherical Alfvén wave, no matter how small its initial amplitude is, becomes non-linear at sufficiently large radii. From previous simulations of Alfvén waves in plane-parallel atmospheres we expected the waves to steepen and produce current sheets in the non-linear regime, which was confirmed by our new calculations. On the other hand we found that even the least non-linear waves were damped out almost completely before 10 R_⊙. A damping of that kind is required by models of Alfvén wave driven winds from old low-mass stars as these winds are mainly accelerated within a few stellar radii.     

Determination of the IMF on the basis of a recently derived SFR history in the solar neighbourhood

The initial mass function (IMF) in the solar neighbourhood is determined on the basis of a recently derived history of the star formation rate (SFR) which shows the presence of a star formation burst about 8 Gyr ago. The observed present-day mass function (PDMF) is considered, and the average past distribution of stars of a given mass is estimated. Two cases are considered, namely (i) constant SFR, and (ii) variable SFR as derived from the new metallicity distribution of G dwarfs. The resulting IMF is compared with previous determinations by Scalo and Kroupa et al., and the variation with stellar mass of the slope of the IMF is compared with reference determinations in the literature.     

Development dynamics of intense solar proton flares

We consider the relationship of electromagnetic radiation in the three most intense flares of solar cycle 23, more specifically, those of October 28, 2003, January 20, 2005, and September 7, 2005, to the acceleration and release of protons into interplanetary space. The impulsive phase of these flares lasted ～ 20 min and consisted of at least three energy release episodes, which differed by their manifestation in the soft (1–8 Å, GOES) and hard (>150 keV, INTEGRAL) X-ray ranges as well as at radio frequencies of 245 MHz and 8.8 GHz. The protons and electrons were accelerated in each episode, but with a different efficiency; the relativistic protons were accelerated only after 5–6min of impulsive-phase development after the onset of a coronal mass ejection. It is at this time that maximum hard X-ray fluxes were observed in the September 7, 2005 event, which exceeded severalfold those for the other two flares considered. We associate the record fluxes of protons with energies > 200MeV observed in the heliosphere in the September 7, 2005 event with the dynamics of the impulsive phase. The extreme intensities of the microwave emission in the October 28, 2003 and January 20, 2005 events were probably attributable to the high-energy electron trapping conditions and did not reflect the acceleration process.