A Closure Study of Aerosol Hygroscopic Growth Factor during the 2006 Pearl River Delta Campaign

Measurements of aerosol physical, chemical and optical parameters were carried out in Guangzhou, China from 1 July to 31 July 2006 during the Pearl River Delta Campaign. The dry aerosol scattering coefficient was measured using an integrating nephelometer and the aerosol scattering coefficient for wet conditions was determined by subtracting the sum of the aerosol absorption coefficient, gas scattering coefficient and gas absorption coefficient from the atmospheric extinction coefficient. Following this, the aerosol hygroscopic growth factor, f(RH), was calculated as the ratio of wet and dry aerosol scattering coefficients. Measurements of size-resolved chemical composition, relative humidity (RH), and published functional relationships between particle chemical composition and water uptake were likewise used to find the aerosol scattering coefficients in wet and dry conditions using Mie theory for internally- or externally-mixed particle species [(NH₄)₂SO₄, NH₄NO₃, NaCl, POM, EC and residue]. Closure was obtained by comparing the measured f(RH) values from the nephelometer and other in situ optical instruments with those computed from chemical composition and thermodynamics. Results show that the model can represent the observed f(RH) and is appropriate for use as a component in other higher-order models.     

Experiment on Coordinated Observation of Offshore Typhoon in China

The lack of sufficient direct observation data of typhoon fine structure is the main bottleneck that restricts the further development of typhoon discipline and forecasting. This paper briefly introduced the basic information of the National Key R&D Program of China, entitled “Experiment on Coordinated Observation of Offshore Typhoon in China”, which started in early 2019. Firstly, the importance and necessity of the program around the national needs on typhoon-related disaster reduction and prevention were explained. Then, the coordinated observation difficulties and frontiers in the current typhoon discipline situation from the development and improvement of the physical mechanism and key forecasting technologies were shown. The overview of the direct observation instrument and platform, the field campaign and the parameterization techniques related to physical process in typhoon numerical modeling was provided. Finally, the key scientific and technical issues and main research contents of the program were given.     

Effects of Dropsonde Data in Field Campaigns on Forecasts of Tropical Cyclones over the Western North Pacific in 2020 and the Role of CNOP Sensitivity

Valuable dropsonde data were obtained from multiple field campaigns targeting tropical cyclones, namely Higos,Nangka, Saudel, and Atsani, over the western North Pacific by the Hong Kong Observatory and Taiwan Central Weather Bureau in 2020. The conditional nonlinear optimal perturbation(CNOP) method has been utilized in real-time to identify the sensitive regions for targeting observations adhering to the procedure of real-time field campaigns for the first time. The observing system experiments...     

联合战役地形分析

首次提出联合战役地形分析的概念,并分析了联合战役地形分析应用的主要时机和要求。论述确定地形分析基本任务的逻辑关系,并分别研究了联合战役地形分析各基本内容的概念与分析方法。     

’92中国GPS会战（A级网）数据处理分析

讨论了应用武汉测绘科技大学改进到微机上的ＧＡＭＩＴ软件处理’９２中国ＧＰＳ会战的国内数据以及用ＧＰＳＡＤＪ软件的多站网处理模块进行全网平差的技术方案，着重论述了数据处理所遇到的问题及解决方法，最后分析了成果精度。     

Detection of the wave-like structures in the F-region electron density: Two station measurements

Comparative studies of short-term ionospheric variability in the F region ionosphere during rapid sequence sounding campaign “HIRAC/SolarMax” (23–29 April 2001) are presented. The ionospheric short-term fluctuations have been studied in detail using measurements from vertical sounding at Ebro (40.8 °N, 0.5 ° E) and Průhonice (49.9 °N, 14.5 °E) in the period range from 15 minutes to 2 hours. The electron density measurements contain variations that indicate the possible presence of propagating gravity waves. Regular wave-like bursts were found during quiet days at both stations in electron concentration in F region, with an increase of the oscillation activity after sunrise and then during late afternoon, and at sunset and after sunset. Solar Terminator is assumed to be one of the sources of the regular wave bursts detected in the ionosphere during campaign HIRAC. As expected, substantial intensification in longer period gravity waves was found to occur during the disturbed period on April 28. Particular enhancement of the wave-like activity during disturbed day is discussed, being significant evidences of a change of the wave-like activity pattern at a height around 200 km.     

POPCORN: A Field Study of Photochemistry in North-Eastern Germany

The intensive field study POPCORN (Photo-Oxidant Formation by Plant Emitted Compounds and OH Radicals in North-Eastern Germany) was carried out in a rural area of North-Eastern Germany during August 1994. An overview of the objectives, measurements and major results of this campaign is presented. Measurements of a set of relevant atmospheric trace compounds, including the hydroxyl radical, along with meteorological data were performed to increase the understanding of OH radical chemistry and photo-oxidant formation. Additionally, plant emissions and the exchange of trace gases between a maize field and the atmosphere were investigated. Budgets of selected trace gases were calculated to assess the relative importance of local sources, chemistry or transport. Intercomparisons between measurement techniques were a central issue of POPCORN and included measurements of OH, hydrocarbons, formaldehyde, photolysis frequencies and vertical fluxes. OH radical concentrations were measured simultaneously by LIF (Laser Induced Fluorescence) and DOAS (Differential Optical Absorption Spectroscopy). Both methods showed good agreement. Maximum OH concentrations were around 107 cm–3 and the diurnal cycles closely followed the rate of primary production via ozone photolysis. Generally, the trace gas composition during POPCORN was characterized by relatively low concentrations of most compounds, e.g. CO: 85–200 ppb, ethane: 0.6–2 ppb, and moderate NOx levels: 0.5–5 ppb (at noontime). Concentrations of individual biogenic volatile organic compounds (VOC) were mostly well below 100 ppt. However, formaldehyde and acetaldehyde which partly originate from biological sources were observed at mixing ratios of some ppb.     

Determination of mechanical properties of traditional masonry walls in dwellings of Faial Island,Azores

The determination of mechanical properties of masonry walls is a fundamental pre‐requisite for the characterization of the seismic response of traditional buildings, which helps on the definition of adequate rehabilitation and strengthening procedures. This paper presents a testing campaign carried out in the Cedros region of Faial Island, Azores, hit by the July 98 earthquake, aiming at the determination of physical and mechanical properties of stone masonry walls, namely the mass density and Young's modulus. The paper describes the developed testing techniques as a contribution to the study and the preservation of traditional masonry buildings. Copyright © 2002 John Wiley & Sons, Ltd.     

利用数字地球技术打赢未来海上数字化战争

在分析了数字地球的基本概念和有关建立数字地球的关键技术基础上,就我国海军如何利用这一新技术打赢未来海上数字化战争进行了基础性的探讨和研究。