近10年我国天体测量的发展

简述天体测量学研究的内各以及与各相关学科之间的关系；描述近10年来国际天体测量研究的进展和前沿课题；叙述我国天体测量研究的历史背景和研究基础，以及近10年来在国家自然科学基金委员会和其他科学组织支持下取得的成果，并对今后10～20年我国天体测量的发展提出初步看法。     

Shock temperatures in anorthite glass

Summary. Temperatures of CaAl₂Si₂O₈ (anorthite glass) shocked to pressures between 48 and 117 GPa have been measured in the range from 2500 to 5600 K, using optical pyrometry techniques. The pressure dependence of the shock temperatures deviates significantly from predictions based on a single high-pressure phase. Either a variable specific heat, or the existence of three phase transitions, at pressures of about 55, 85 and 100 GPa and with transition energies of about 0.5 MJ kg⁻¹ each (∼ 1.5 MJ kg⁻¹ total) can explain the shock-temperature data. The proposed phase transition at 100 GPa can possibly be identified with the stishovite melting transition. Theoretical models of the time dependence of the thermal radiation from the shocked anorthite based on the geometry of the experiment and the absorptive properties of the shocked material yield good agreement with observations, indicating that it is not necessary to invoke intrinsic time dependences to explain the data in many cases. Observed time dependences were used to calculate absorption coefficients of the shocked material of from about 2 mm⁻¹ to greater than 24 mm⁻¹– an increasing function of shock pressure. The assumption that the shocked material radiates as a black body is supported by the theoretical model, and by the close agreement between measured and calculated black body spectral radiance as a function of wavelength.     

红外相机CASCAM光学设计

介绍紫金山天文台研制的光学-近红外相机CASCAM（Chinese Academy of Science，CAMera)的光学系统设计．CASCAM相机以红外列阵HAWAII-1和光学CCD为探测器，配备国家天文台兴隆观测站2．16米和1．26米望远镜进行0．4—2．5μm波长范围的成像和偏振成像观测．相机的光学系统由F／9→F／6缩焦系统和Offner反射成像系统构成．优化设计结果表明，光学设计方案已满足天文观测的要求．CASCAM相机在设计上实现了光学-近红外很宽波段的消色差变焦，并在楔形分柬片、常温滤光片轮和折射式焦面摆动技术等方面进行了新的尝试．     

用CE-318太阳光度计资料研究银川地区气溶胶光学厚度特性

根据CE-318数据,利用Bouguer定律计算了银川地区的大气气溶胶光学厚度,并分析其变化特征。结果表明,该地区大气气溶胶光学厚度具有明显的日变化和季节变化。日变化有4种类型：1)变化相对稳定;2)整体上呈上升的趋势;3)早晚小,中午大;4)早晨09-11时出现峰值,其他时间变化较小。季节变化则是冬、春季节大,秋季次之,夏季最小;春季大气中的主要成分是沙尘,冬季大气的主要成分是人类活动排放的颗粒物,夏季由于降水多,气溶胶数浓度较低,气溶胶光学厚度较小。     

小洋山岛大气气溶胶光学厚度的特征分析

小洋山岛位于上海东南面距海岸线约30km处,四面环海,研究其上空的大气气溶胶光学特性对了解我国东部沿海地区及其近海海域的环境和气候影响等都具有重要的意义。对于近岸海岛的气溶胶光学厚度(AOD)观测,至今国内尚未见这方面的实测资料与分析。本次实验利用2006～2007年连续观测得到的AOD值,分析了AOD的季节变化及其与地面风向、湿度和能见度等气象要素的关系,并给出了气溶胶消光谱。分析发现:小洋山地区AOD具有春季最大,冬季次之,秋季较小的特点,而且在低能见度情况下,气溶胶以大粒子为主;盛行西风时,AOD值增大且大粒子比重增加;AOD与湿度有较好的正相关关系。     

利用AMSU-B和GOES-9卫星资料对热带气旋“蒲公英”的分析

利用NOAA-16/AMSU-B三水汽通道微波亮温差和GOES-9红外亮温阈值对热带气旋深厚对流云进行检测,同时利用GOES-9可见光、红外、水汽多光谱通道特征对热带气旋云系进行识别,通过一次台风“蒲公英”个例,对热带气旋在微波和光学遥感图像上的深厚对流云进行分析。结果表明,微波和光学遥感资料均能对热带气旋深厚对流云进行有效识别,检测结果基本一致,但识别出的对流云,微波范围较小,光学遥感范围较大,这可能是由于光学遥感仅能获得云顶信息,将对流云顶部覆盖的卷云错判造成的;即使采用较低亮温阈值,光学遥感也很难将这部分卷云完全分离,而微波对云更具穿透性,在深厚对流云的识别方面具有独特优势;三水汽通道间微波亮温差反映了深厚对流云的发展强度,可间接揭示热带气旋的发展情况。     

Influences of Two Convective Schemes on the Radiative Energy Budget in GAMIL1.0

The Grid-point Atmospheric Model of IAP LASG version 1.0 (GAMIL1.0) is used to investigate the impacts of different convective schemes on the radiative energy budget.The two convective schemes are Zhang and McFarlance (1995)/Hack (1994) (ZM) and Tiedtke (1989)/Nordeng (1994) (TN).Two simulations are performed:one with the ZM scheme (EX_ZM) and the other with the TN scheme (EX_TN).The results indicate that during the convective process,more water vapor consumption and temperature increment are found in the EX_ZM,especially in the lower model layer,its environment is therefore very dry.In contrast,there is a moister atmosphere in the EX_TN,which favors low cloud formation and large-scale condensation,and hence more low cloud fraction,higher cloud water mixing ratio,and deeper cloud extinction optical depth are simulated,reflecting more solar radiative flux in the EX_TN.This explains why the TN scheme underestimates the net shortwave radiative flux at the top of the atmosphere and at surface.In addition,convection influences longwave radiation,surface sensible and latent heat fluxes through changes in cloud emissivity and precipitation.     

Aerosol optical depths at Mohal-Kullu in the northwestern Indian Himalayan high altitude station during ICARB

First time observations of spectral aerosol optical depths (AODs) at Mohal (31.9°N, 77.11°E; altitude 1154 m amsl) in the Kullu valley, located in the northwestern Indian Himalayan region, have been carried out during Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB), as a part of the Indian Space Research Organisation-Geosphere Biosphere Program (ISRO-GBP). AODs at six wavelengths are obtained using Microtops-II Sunphotometer and Ozonometer. The monthly mean values of AOD at 500 nm are found to be 0.27 ± 0.04 and 0.24 ± 0.02 during March and April, 2006 respectively. However, their monthly mean values are 0.33 ± 0.04 at 380 nm and 0.20 ± 0.03 nm at 870 nm during March 2006 and 0.31 ± 0.3 at 380 nm and 0.17 ± 0.2 at 870 nm during April 2006, showing a gradual decrease in AOD with wavelength. The Ångstrom wavelength exponent ‘α’ had a mean value of 0.72 ± 0.05, implying reduced dominance of fine particles. Further, the afternoon AOD values are higher as compared to forenoon values by ～ 33.0% during March and by ～ 9.0% during April 2006 and are attributed to the pollutant lifted up from the valley by the evolving boundary layer. Besides the long-range transportation of aerosol particles by airmass from the Great Sahara and the Thar Desert regions to the observing site, the high values of AODs have also been influenced by biomass burning and frequent incidents of forest fire at local levels.     

Correlated Radio-Optical Variations on Intraday Timescales

Correlated radio-optical variations on intraday timescales have been observed (e.g. In BLO 0716 714) and such radio intraday variability is suggested to have an intrinsic ori- gin. Recently, multi-wavelength observations, simultaneous at radio, mm-submm, optical and hard X-rays, of 0716 714, show that during a period of intraday/interday variations at ra- dio and mm wavelengths, the apparent brightness temperature of the source exceeded the Compton-limit (～1012 K) by 2--4 orders of magnitude, but no Compton catastrophe (or no high luminosity of inverse-Compton radiation) was detected. It is also found that the intra- day/interday variations at mm-submm wavelengths are consistent with the evolutionary be- havior of a standard synchrotron source and for the intraday/interday variations at centimeter wavelengths opacity effects can play a significant role, which is consistent with the interpreta- tion suggested previously by Qian et al. Thus the apparent high brightness temperatures may probably be explained in terms of Doppler boosting effects due to bulk relativistic motion of the source. We will argue a scenario to simulate the correlations between the radio and optical variations on intraday timescales observed in BLO 0716 714 in terms of a relativistic shock propagating through a jet with a dual structure.