老硐素描方法介绍

我们在普查工作中,为了提高老硐素描的效率,经研究采用了一种新的老硐素描方法,使作图效率达到每日每组(2人)150公尺以上,最高曾达200余公尺(包括坑道测量及地质情况素描,用一般方法每日每组只能作50-80公尺),而且保证了?素描图所要求的精度,提供了矿体产状资料.     

用依巴谷星表归算光电等高仪I型在伊尔库茨克的观测

陕西天台（ＣＳＡＯ）和俄罗斯东西伯利亚物理技术和无线电工程测量研究所（ＶＳＮＩＦＴＲＩ）之间进行的高等仪合作观测研究已进行了三年多,到１９９９年上半年完成了两部纳要的观测,获得了两部无赤续盲区的等高仪星表,主要介绍两部纲要的观测精度（相对依巴谷星表系统）,星入正精度和某些系统误差的分析。从各个方面来看,都达到了预期的合作目标。     

Three-Year Observations of Ozone Columns over Polar Vortex Edge Area above West Antarctica

Ozone vertical column densities (VCDs) were retrieved by Zenith Scattered Light-Differential Optical Absorption Spectroscopy (ZSL-DOAS) from January 2017 to February 2020 over Fildes Peninsula, West Antarctica (62.22°S, 58.96°W). Each year, ozone VCDs started to decline around July with a comparable gradient around 1.4 Dobson Units (DU) per day, then dropped to their lowest levels in September and October, when ozone holes appeared (less than 220 DU). Daily mean values of retrieved ozone VCDs were compared with Ozone Monitoring Instrument (OMI) and Global Ozone Monitoring Experiment 2 (GOME-2) satellite observations and the Modern-Era Retrospective analysis for Research and Applications Version 2 (MERRA-2) reanalysis dataset, with correlation coefficients (R2) of 0.86, 0.94, and 0.90, respectively. To better understand the causes of ozone depletion, the retrieved ozone VCDs, temperature, and potential vorticity (PV) at certain altitudes were analyzed. The profiles of ozone and PV were positively correlated during their fluctuations, which indicates that the polar vortex has a strong influence on stratospheric ozone depletion during Antarctic spring. Located at the edge of polar vortex, the observed data will provide a basis for further analysis and prediction of the inter-annual variations of stratospheric ozone in the future.     

Interdecadal Variability of the East Asian Winter Monsoon and Its Possible Links to Global Climate Change

This paper presents a concise summary of the studies on interdecadal variability of the East Asian winter monsoon (EAWM) from three main perspectives. (1) The EAWM has been significantly affected by global climate change. Winter temperature in China has experienced three stages of variations from the beginning of the 1950s: a cold period (from the beginning of the 1950s to the early or mid 1980s), a warm period (from the early or mid 1980s to the early 2000s), and a hiatus period in recent 10 years (starting from 1998). The strength of the EAWM has also varied in three stages: a stronger winter monsoon period (1950 to 1986/87), a weaker period (1986/87 to 2004/05), and a strengthening period (from 2005). (2) Corresponding to the interdecadal variations of the EAWM, the East Asian atmospheric circulation, winter temperature of China, and the occurrence of cold waves over China have all exhibited coherent interdecadal variability. The upper-level zonal circulation was stronger, the mid-tropospheric trough over East Asia was deeper with stronger downdrafts behind the trough, and the Siberian high was stronger during the cold period than during the warm period. (3) The interdecadal variations of the EAWM seem closely related to major modes of variability in the atmospheric circulation and the Pacific sea surface temperature. When the Northern Hemisphere annular mode/Arctic Oscillation and the Pacific decadal oscillation were in negative (positive) phase, the EAWM was stronger (weaker), leading to colder (warmer) temperatures in China. In addition, the negative (positive) phase of the Atlantic multi decadal oscillation coincided with relatively cold (warm) temperatures and stronger (weaker) EAWMs. It is thus inferred that the interdecadal variations in the ocean may be one of the most important natural factors influencing long-term variability in the EAWM, although global warming may have also played a significant role in weakening the EAWM.     

The First Discovery of a Large Sandstone-type Uranium Deposit in Aeolian Depositional Environment

正The exploration depth of sandstone-type uranium deposits worldwide is mostly less than 700 m, and most of them occur in strata of fluvial facies(Adams et al., 1981; Jin et al., 2016; Hou et al., 2017). Only a few small uranium deposits have been reported in aeolian depositional environments(Isachsen et al., 1955; Li et al.,     

The dynamics and ethnic composition of the population of Russia in the era of imperialism (from the end of the 19th century to 1917)

"The authors critically survey tsarist censuses before the October Revolution and Soviet works on historical demography, and they re-estimate population numbers, natural and mechanical increase, and internal and external migration between 1897 and 1917, as well as changes in ethnic composition."