现代日晕光度计多波段测光系统初步测试结果分析

现代日晕光度计是用于精确测定监测址点的多种大气参量的精密仪器,它已列为我国西部太阳设备选址工作中的重要设备。利用同一架日晕光度计首先对昭通大山包进行了多波段数据采集。在仔细分析初步测光结果的基础上,进一步完善日晕光度计的光学系统。使用改进后的设备对昆明凤凰山址点进行了多次数据采集,都获得了理想数据。这表明日晕光度计的多波段测光系统已能够用于西部太阳选址工作中。     

红外太阳塔抚仙湖老鹰地选址

介绍红外太阳塔抚仙湖老鹰地选址点的初步观测结果以及白日视宁度监测仪－“太阳差分像运行监测仪和闪仪的原理结构及用这两套仪的抚仙湖老鹰地红外太阳塔选址点进行的对比观测实验。     

西行漫谈——太阳西部选址的故事

太阳西部选址队!这是一个响亮的名称,这是一个特别的天文部落,这儿拥有一群不辞辛劳、跋涉奔波在祖国西部最艰苦地区的热血队员,这儿聚集着我国最好的天文选址专家。两年来,我国西部地区蕴藏的丰厚天文资源正逐渐向世人揭开神秘的面纱,寻找到未来一流天文址点的信心在他们的心中日益增强。     

丽江高美古2号点的大气视宁度观测

介绍了2007年11月至2008年1月15日在丽江高美古2号选址点的大气视宁度及其它天文气象参数观测结果.数据分析显示:观测时间段内高美古2号点平均r 0为8.74cm(FWHM 1.27″), 观测到的r0的极大值为20.47cm(FWHM 0.54″).     

国内首架日冕仪落户云南丽江

日冕仪的重要功能是通过人造日食的巧妙方式来直接观测太阳最外层大气——日冕层。借助日冕仪,人们在常规太阳观测条件下就可以欣赏美丽的日冕以及壮丽的日冕爆发过程。我们的前辈自上世纪50年代末就开始了针对日冕观测址点的不断考察,但遗憾的是一直未能寻找到理想的候选点。随着近几年我国西部太阳选址工作的不断深入,我们选址科考队得到了一批颇有价值的潜在理想址点,大香格里拉地区便是其中得到证认的区域之一。滇西北的丽江高美古天文基地就位于大香格里拉地区南部,海拔较高,空气十分洁净,每年旱季日照充沛。高美古目前拥有东亚最大的地面天文望远镜集群,为我们日冕仪观测站的建立提供了极其便利的基本条件。     

白日视宁度监测仪和在抚仙湖的初步观测结果

报导了用南方基地云南天文台太阳差分像运动视宁度监测仪和美国国立太阳天文台的太阳闪烁仪 ,在云南省澄江县抚仙湖老鹰地红外太阳塔选址点进行的对比观测 ,简要地介绍了这两种视宁度测量方法的原理 ,对观测的初步结果进行了分析。     

云南红外太阳塔选址及其结果

介绍了云南太阳光学选址的历程。主要叙述了自1996年开始的红外太阳选址的过程:初选踏勘,比对筛选、定点观测。最佳选点为澄江县抚仙湖畔的半岛老鹰地。     

白日视宁度监测仪和在抚仙湖的初步观测结果

报导了用南方基地云南天文台太阳差分像运动视宁度监测仪和美国国立太阳天文台的太阳闪烁仪,在云南省澄江县抚仙湖老鹰地红外太阳塔选址点进行的对比观测,简要地介绍了这两种视宁度测量方法的原理,对观测的初步结果进行了分析。     

CCD离焦对现代日晕光度计测量结果影响分析

现代日晕光度计（Sky Brightness Monitor,SBM）是一种测定天文址点白昼大气参量的精密仪器,它已成为国际上太阳选址工作的重要设备之一。与国外同类设备不同的是,云南天文台研制的现代日晕光度计上的CCD相机系统可以被简单拆卸并保存,有利于选址踏勘阶段的携带和运输。为获取组装现代日晕光度计设备时可能存在的CCD离焦所导致的测量误差,于2011年6月在新疆奇台县和宁夏石嘴山市利用当地稳定的日照条件做了多次CCD大离焦量快变试验。统计结果表明,现代日晕光度计的CCD显著离焦可造成的相对测量误差约在6％之内。在正常情况下,即观测者基本按照物镜旋筒刻线标志在望远镜上安装CCD设备时,日晕测量的相对误差一般远小于6％。因此认为这种系统误差对优良址点的测量影响基本可以忽略。     

云南红外太阳塔选址及其结果

介绍了云南太阳光学选址的历程，主要叙述了自1996年开始的红外太阳选址的过程：初选踏勘，比对筛选、定点观测。最佳选点为澄江县抚仙湖畔的半岛老鹰地。     

Mineral aerosol properties observed in the northwest region of China

The aerosol optical depth and Ångström exponent for 2002–2003 were derived from CE_318 sun/sky photometer observations carried out at Tazhong, Hetian, Minqin and Dunhuang, located in the source regions of mineral aerosols in China. The observed aerosol properties, including their diurnal and monthly variations, are given for each of the observation sites. The effects of meteorological parameters, such as wind and relative humidity, on aerosol optical depth are analyzed.     

Gulmarg,Kashmir, India: Potential Site for Optical Astronomical Observations

The site characteristics of Gulmarg, Kashmir at an altitude of about 2743.2 m above sea level is based on analysis of meteorological conditions, cloud cover, temperature, wind speed, wind direction, relative humidity and atmospheric pressure, etc. Analysis and characterization of meteorological conditions suggest that Gulmarg, Kashmir is a potential site for carrying out photometric as well as spectroscopic observations of celestial objects.     

Study of cosmic ray intensity in relation to the interplanetary magnetic field and geomagnetic storms for solar cycle 24

In the present study, we investigate the association of cosmic ray intensity (CRI) with various solar wind parameters (i.e. solar wind speed V, plasma proton temperature, plasma proton density), interplanetary magnetic field (IMF B), geomagnetic storms (GSs), averaged planetary A-index (Ap index) and sun spot number (SSN) for the period 2009–2016 (solar cycle 24) by using their daily mean average. To find the association of CRI with various solar wind parameters, GSs, IMF B, Ap index and SSN, we incorporate the analysis technique by superposed-epoch method. We have observed that CRI decreases with the increase in IMF B. Moreover the time-lag analysis has been performed by the method of correlation coefficient and observed a time lag of 0 to 2 day between the decrease in CRI and increase in IMF B. In addition, we show that the CRI is found to decrease in a similar pattern to disturbance storm time (Dst index) for most of the period of solar cycle 24. The high and positive correlation is found between CRI and Dst index. The CRI and Ap index are better anti-correlated to each other than CRI and IMF. CRI and SSN are positively correlated with each other. Solar wind parameters such as solar wind speed V is a CR-effective parameter while plasma proton temperature and plasma proton density are not CR-effective parameters. The indicated parameters such as Dst index, Ap index, IMF B and solar wind parameters such as solar wind speed V, plasma proton temperature, plasma proton density shows a kind of irregular variations for solar cycle 23 and 24 while CRI and SSN shows distinct behaviour for the two cycle.     

Solar magnetic cycle dependence in corotating modulation of galactic cosmic rays

We study the temporal evolution of cosmic ray intensity during ～27-day Carrington rotation periods applying the method of superposed epoch analysis. We discuss about the average oscillations in the galactic cosmic ray intensity, as observed by ground based neutron monitors, during the course of Carrington rotation in low solar activity conditions and in different polarity states of the heliosphere (A<0 and A>0). During minimum and decreasing phases in low solar activity conditions, we compare the oscillation in one polarity state with that observed in other polarity state in similar phases of solar activity. We find difference in the evolution and amplitude of ～27-day variation during A<0 and A>0 epoch. We also compare the average variations in cosmic ray intensity with the simultaneous variations of solar wind parameters such as solar wind speed and interplanetary magnetic field strength. From the correlation analysis between the cosmic ray intensity and the solar wind speed during the course of Carrington rotation, we find that the correlation is stronger for A>0 than A<0.     

Site-testing at Muztagh-ata site Ⅰ:ground meteorology and sky brightness

Site-testing is crucial for achieving the goal of scientific research and analysis of meteorological and optical observing conditions,one of the associated basic tasks.As one of three potential sites to host the 12-meter Large Optical/infrared Telescope(LOT),the Muztagh-ata site,which is located on the Pamir Plateau in Xinjiang,in west China,began its site-testing task in the spring of 2017.In this paper,we firstly start with an introduction to the site and then present a statistical analysis of the ground-level meteorological properties such as air temperature,barometric pressure,relative humidity,and wind speed and direction,recorded by an automatic weather station with standard meteorological sensors for a two-year duration.We also show the monitoring results of sky brightness during this period.     

On the relationship between ground temperature histories and meteorological records: a report on the Pomquet station

An experimental air–ground climate station is operating in Pomquet, Nova Scotia, monitoring meteorological (surface air temperatures at three heights, wind velocity and direction, incoming solar radiation, precipitation, snow depth and relative humidity) and ground thermal variables (soil temperatures at depths of 0, 5, 10, 20, 50 and 100 cm). Readings are taken every 30 s and 5 min averages are stored, in order to characterize the energy exchanges at the air ground interface. Here, I report on the first year of operation. For spring, summer and fall, we find that soil temperatures track surface air temperatures with amplitude attenuation and phase lag with depth confirming that heat conduction adequately describe the soil thermal field at the Pomquet site. For winter conditions, we find that heat transfer is dominated by latent heat released during soil freezing and to a lesser extent by the insulating affect of snow cover. A numerical model of heat conduction was used in order to estimate the magnitude of the heat released by freezing during the winter months. I also show that there is an inverse correlation for the difference between soil (100 cm) and air temperatures and the incoming solar radiation at the site.     

Meteorological conditions at the Caucasus Observatory of the SAI MSU from the results of the 2007–2015 campaign

Based on the measurements performed from 2007 to 2015 at the summit of Mount Shatdzhatmaz adjacent to the 2.5-m telescope at the Caucasus Observatory of the SAI MSU, we have determined the statistical characteristics of basic meteorological parameters: the ambient air temperature, the ground wind speed, and the relative humidity. The stability of these parameters over the entire period of our measurements and their variations within an annual cycle have been studied. The median temperature on clear nights is +3.2°C, although there are nights with a temperature below ?15°C. The typical ground wind speed is 3 m s^?1; the probability of a wind stronger than 10 m s^?1 does not exceed 2%. The losses of observing time due to high humidity are maximal in the summer period but, on the whole, are small over a year, less than 10%. We have estimated the absolute water vapor content in the atmosphere, which is especially important for infrared observations. Minimum precipitablewater vapor is observed in December–February; the median value over these months is 5 mm. We additionally provide the wind speeds at various altitudes above the ground (from 1 to 16 km) that we obtained when measuring the optical turbulence. We present the results and technique of our measurements of the annual amount of clear night astronomical time, which is, on average, 1320 h, i.e., 45% of the possible one at the latitude of the observatory. The period from mid-September to mid-March accounts for about 70% of the clear time. A maximum of clear skies is observed in November, when its fraction reaches 60% of the possible astronomical night time.     

丽江高美古的气象观测

本文报道了１９９４年７月－１９９５年１２月期间丽江高美古的云量、风向、风速、温度、湿度和温度日较差等气象要素的观测结果。     

Comparison of single-site interplanetary scintillation solar wind speed structure with coronal features

Interplanetary Scintillation (IPS) Observations were made during the period 1984–1990 using a single radio telescope at 103 MHz situated at Thaltej (Ahmedabad), India. Solar wind speeds were estimated using a recently developed method based on matching the observed IPS spectra with model solar wind spectra for Kolmogorov turbulence. The best-fit speeds derived are traced back to a source surface, and average velocity maps are made for each year, averaging over a number of Carrington rotations. It is found that the resulting single-site, large-scale IPS speed structure agrees well with that derived from 3-site observations from earlier workers. The IPS speed structure during this period was compared with other coronal features. Nearly 85% of the observed high-speed regions were associated with coronal holes. At solar minimum, in 1986, a quasi-sinusoidal, narrow belt of slow solar wind was observed which matched well with the neutral line structure of the solar magnetic field and the belt of active centers. Near solar maximum, in 1990, the speed structure was chaotic, similar to that of the neutral line, with low speed regions appearing all over the source surface.