The spatial and temporal distribution and characteristics of inorganic ion concentrations of TSP in the Tarim Basin

Based on Total Suspended Particulates （TSP） observations of Tazhong, Tikanli, Kashi and Minfeng in 2009, combined wa- ter-soluble inorganic ion analyses, this paper studied the spatial and temporal distribution of TSP in the Tarim Basin and analyzed concentration characteristics. The results are as follows： （1） monthly average TSP concentrations shows a similar trend in Tazhong, Tikanli, Kashi and Minfeng with peak values in April-May and low values in November-December. As for the quarter average mass concentration trends, spring has the highest value, followed by summer and autumn, and winter is the lowest; （2） total annual concentration trend of water-soluble inorganic ions in TSP is as follows： Tazhong 〉 Tikanli 〉 Minfeng 〉 Kashi. SO4^2- concentra- tions are 58%, 50%, 54% and 51% of total ion concentration; Ca^2＋ concentrations are 13%, 16%, 16% and 11%; Na^＋ concentra- tions are 12%, 13%, 10% and 12% and Cl^- concentrations are 12%, 16%, 11% and 22%, respectively. Therefore, sulfate, calcium, sodium and chloride ions are the main inorganic components of TSP in the Tarim Basin; （3） the correlation coefficients of anions and cations in Tikanli, Minfeng, Kashi and Tazhong are 0.99, 0.99, 0.25 and 0.91, respectively; the average anion concentrations are 2.57, 2.12, 2.15 and 3.02 times the average cation concentrations, indicating that ions were unbalanced; （4） SO4^2-/NO3^- ratio is much larger than the ratio of coal-fired emissions SO4^2-/NO3^-, thus the impact of fixed emission sources in the four regions on the atmosphere is far greater than that of mobile emission sources.

Analysis of Spatial and Temporal Distribution Characteristics of Air Pollutants in Tibet

This paper takes seven cities in the Tibet Autonomous Region as the study area,and collects data from more than 20 monitoring stations covering the Tibet Autonomous Region in the ambient air quality online monitoring platform to analyze the spatial and temporal variation characteristics of PM_(10),PM_(2.5),SO_(2),NO_(2),CO and O_(3)MAD 8(ozone daily maximum 8-h average).The results show that(1)the multi-year average PM_(2.5)concentration in Tibet Autonomous Region is 12.03μg/m^(3);the multi-year average PM_(10)concentration is 28.27μg/m^(3);the multi-year average CO concentration is 0.59 mg/m^(3);the multi-year average NO_(2)concentration is 12.34μg/m^(3);the multi-year average SO_(2)concentration is 7.00μg/m^(3);the multi-year average value of O_(3)is 89.54μg/m^(3).The concentrations of atmospheric pollutants all meet the primary concentration limits of the Ambient Air Quality Standards(GB 3095-2012).(2)The air environment in the Tibet Autonomous Region in spring is relatively poor,with about 20%of excellent days and 80%of good days.The air environment is relatively good in summer,autumn and winter,with about 65%-87%of excellent days and 35%-13%of good days.The air environment quality of Tibet Autonomous Region is excellent:winter>autumn>summer>spring,and good:spring>summer>autumn>winter.(3)Except for NO_(2)which is more influenced by automobile exhaust and SO_(2)which is more influenced by man-made source in winter,the ambient air quality in Tibet Autonomous Region is less influenced by industry.The variability characteristics of the six atmospheric pollutants studied in this paper are strongly correlated with the unique natural environment of Tibet(air pressure,altitude,wind speed,temperature,precipitation,solar radiation,etc).

Study on Air Quality and Spatial and Temporal Distribution Characteristics of Air Pollutants in Sichuan Province from 2017 to 2021

Atmosphere is the basic environmental element on which human beings depend for survival and development,and its environmental quality is directly related to sustainable socio-economic development.China is currently in a period of accelerated urbanization,accompanied by industrialization and urbanization bringing environmental pollution problems more and more prominent.Therefore,it is particularly important to strengthen the management of atmospheric quality and improve the level of atmospheric environment.To this end,the spatial and temporal distribution characteristics of AQI and six types of air pollutants in eight prefecture-level cities were analysed and studied using the month-by-month air quality monitoring data of Sichuan Province from 2017 to 2021.The results show that:(1)according to the Ambient Air Quality Standards,Chengdu,Mianyang,Zigong,Luzhou and Deyang do not meet the concentration limits of PM_(2.5),Zigong and Suining do not meet the concentration limits of PM_(10),Chengdu does not meet the concentration limits of NO_(2),and all eight cities meet the concentration limits of NO_(2)and SO_(2).(2)The seasonal concentration changes of PM_(2.5),PM_(10)and NO_(2)have the same characteristics,showing that they are winter>spring>autumn>summer.The seasonal concentration changes of CO are winter>autumn>spring>summer;the seasonal concentration changes of SO_(2)are winter>spring>summer>autumn;the seasonal concentration changes of O_(3)are summer>spring>autumn>winter.

Study of the characteristics of concentration sensing based on FBG Fabry-Perot cavity

Fiber Bragg grating Fabry-Perot (FBG F-P) cavity is used as the sensing model to measure the refractive index of the liquid solution. The cladding of the fiber, which is used as the F-P cavity, is etched by HF solution to enhance the sensitivity to the external refractive index. The experimental results show that with the concentration change of the external solution, the effective refractive index of etched fiber will change, thus the spectra of FBG F-P cavity will appear a spilt point. The relationship between the wavelength at spilt point and the effective refractive index of etched fiber is approximately linear, and also periodical. The sensing model is theoretically analyzed based on transfer matrix method, and the corresponding mathematic model is established.

Monitoring atmospheric nitrous oxide background concentrations at Zhongshan Station,east Antarctica

At present,continuous observation data for atmospheric nitrous oxide（N_2O） concentrations are still lacking,especially in east Antarctica.In this paper,nitrous oxide background concentrations were measured at Zhongshan Station（69°22′25″S,76°22′14″E）,east Antarctica during the period of 2008–2012,and their interannual and seasonal characteristics were analyzed and discussed.The mean N_2O concentration was 321.9 n L/L with the range of 320.5–324.8 n L/L during the five years,and it has been increasing at a rate of 0.29% year-1.Atmospheric N_2O concentrations showed a strong seasonal fluctuation during these five years.The concentrations appeared to follow a downtrend from spring to autumn,and then increased in winter.Generally the highest concentrations occurred in spring.This trend was very similar to that observed at other global observation sites.The overall N_2O concentration at the selected global sites showed an increasing annual trend,and the mean N_2O concentration in the Northern Hemisphere was slightly higher than that in the Southern Hemisphere.Our result could be representative of atmospheric N_2O background levels at the global scale.This study provided valuable data for atmospheric N_2O concentrations in east Antarctica,which is important to study on the relationships between N2 O emissions and climate change.

Numerical investigation of the concentric annulus flow around a cylindrical body with contrasted effecting factors

This paper studies the wall-bounded flow around a cylindrical at a high Reynolds numbers body in a determined computational domain, with simulations of the 3-D, turbulent concentric annulus flow in a straight pipe. Numerical results show that a reversing zone, appearing as a tongue zone with nested velocities higher than the surrounding area, exists behind the cylindrical body. The annulus space is a region of high velocity and low pressure. The zero velocity, of combined the X- velocity and the Y- velocity, exists in the cross sections and no vortex shedding is formed behind the attaching cylinders. Among all investigated effecting factors, the diameters of the attaching and the main cylinders affect the wake feature behind the cylindrical body while the main cylinder length does not affect the distribution tendency of the flow field. The diameters of the main cylinder and the pipe affect the pressure values and the distribution tendencies on the main cylinder surface. Obviously, the increase of the pipe diameter reduces the drag coefficient of the cylindrical body and the increase of the diameter of the main cylinder increases the drag coefficient greatly. The numerical investigation of the concentric annulus flow provides foundations for further improvements of the intricate flow studies.