Soliciting Contributions to a Special Issue of "Current Research on Atmospheric Aerosols and Trace Gases over the Polar Regions" in Advances in Polar Science

Dear Colleagues, We would like to invite you to submit manuscripts to a special issue entitled ＂Current Research on Atmospheric Aerosols and Trace Gases over the Polar Regions＂ of the Journal Advances in Polar Science （APS）. APS is an international, peer-reviewed journal jointly sponsored by the Polar Research Institute of China （PRIC） and the Chinese Arctic and Antarctic Administration （CAA）. It is a quarterly journal published in March, June, September and December by Science Press of China and circulated internationally （ISSN 1674-9928, CN 31-2050/P）. Articles published in APS are free of charge with generous funding from PRIC. For more details, please visit the APS＇s websites. Thank you in advance for your consideration to submit manuscripts to this special issue, and we encourage you to share this announcement broadly with interested colleagues.

MAX-DOAS and in-situ measurements of aerosols and trace gases over Dongying,China:Insight into ozone formation sensitivity based on secondary HCHO

This study presents a comprehensive overview of the atmospheric pollutants including Sulfur dioxide(SO_(2)),Nitrogen dioxide(NO_(2)),Formaldehyde(HCHO),Particulate Matter PM;PM_(10):diameter≤10μm,and PM_(2.5):diameter≤2.5μm,and Ozone(O_(3)),over Dongying(Shandong Province)from March-April 2018 and September-October 2019 by employing ground-based Multiple Axis Differential Optical Absorption Spectroscopy(MAX-DOAS)observations along with the in-situ measurements attained by the national air quality monitoring platform.The concentrations of SO_(2)and NO_(2)were under the acceptable level,while both PM_(2.5),and PM_(10)were higher than the safe levels as prescribed by national and international air quality standards.The results depict that 21%of the total observation days were found to be complex polluted days(PM_(2.5)>35μg/m^(3) and O_(3)>160μg/m^(3)).The secondary HCHO was used for accurate analysis of O_(3)sensitivity.A difference of 11.40%and 10%during March-April 2018 and September-October 2019 respectively in O_(3)sensitivity was found between HCHO_(total)/NO_(2)and HCHO_(sec)/NO_(2).The results indicate that primary HCHO have significant contribution in HCHO.O_(3)formation predominantly remained to be in VOC-limited and transitional regime during March-April 2018 and September-October 2019 in Dongying.These results imply that concurrent control of both NO_(x) and VOCs would benefit in ozone reductions.Additionally,the criteria pollutants(PM,SO_(2),and NO_(2))depicted strong correlations with each other except for O_(3)for which weak correlation coefficient was obtained with all the species.This study will prove to be baseline for designing of air pollution control strategies.

Synthesis of corrected multi-wavelength spectrometers for atmospheric trace gases

The method for synthesis of corrected three-wavelengths spectrometers for trace gas components of atmo- sphere on the basis of development of mathematical model has been suggested. The classification table for possible structures of corrected spectrometers is considered. The synthesis allows to reveal some new variants for development of three-wavelength spectrometers for trace gas components of atmosphere. For experimental checkup of achieved theoretical results, a laboratory pattern of three-wavelength spectrome- ter is developed and tested.

Study on the Trace Species in the Stratosphere and Their Impact on Climate

The trace gases （O3, HCl, CH4, H2O, NO, NO2） in the stratosphere play an important role, not only in the photochemical processes in which the ozone layer destroyed, but also in the radiative processes. In this paper, we review the works on the distribution and variation of the trace gases in the stratosphere and their impact on climate, which have been carried out at the University of Science and Technology of China in the recent 20 years. The Halogen Occultation Experiment （HALOE） data were used to analyse the distribution and variation of the mixing ratio of these trace gases and the temperature trends in the stratosphere in the most recent decade. And the reanalyzed National Centers of Environmental Prediction （NCEP）/NCAR data were also used to give the temperature trends and compared with the results from HALOE data. Numerical simulations were also carried out to study the impact of ozone depletion on the global climate. In this review, the distributions of the trace gases, especially those over the Qinghai-Xizang Plateau, are discussed, and the variations and trends for the trace gases in various levels in the stratosphere have been given for the most recent decade. The temperature variation and the cooling trend obtained from HALOE data in the middle and lower stratosphere for the last 13 years are significant, which agree well with the results from NCEP/NCAR data. While the temperature trend in the upper stratosphere in this period do not seem to have much cooling. The numerical simulations show that either the Antarctic ozone hole or the ozone valley over Qinghai-Xizang Plateau affect not only the temperature and circulation in the stratosphere, but also the temperature, pressure and wind fields in the troposphere, then lead to the global climate change.

Aerosol Spectra and New Particle Formation Observed in Various Seasons in Nanjing

The aerosol number spectrum and gas pollutants were measured and the new particle formation （NPF） events were discussed in Nanjing. The results showed that the size distributions of aerosol number concen- trations exhibited distinct seasonal variations, implying the relations of particle sizes and their sources and sinks. The number concentrations of particles in the nuclei mode （10-30 nm）, Aitken mode （30-100 nm）, accumulation mode （100 -1000 nm） and coarse mode （〉1μm） varied in the order of summer 〉 spring 〉 autumn, summer 〉 autumn 〉 spring, autumn 〉 summer 〉 spring, and spring 〉 autumn 〉summer, re- spectively. The diurnal variation of total aerosol number concentrations showed three peaks in all observed periods, which corresponded to two rush hours and the photochemistry period at noon. In general, the NPF in summer occurred under the conditions of east winds and dominant air masses originating from marine areas with high relative humidity （50%-70%） and strong solar radiations （400 -700 W m-2）. In spring, the NPF were generally accompanied by low relative humidity （14%-30%） and strong solar radiations （400-600 W m-2）. The new particle growth rates （GR） were higher in the summertime in the range of 10- 16 nm h-1. In spring, the GR were 6.8-8.3 nm h-1. Under polluted air conditions, NPF events were seldom captured in autumn in Nanjing. During NPF periods, positive correlations between 10- 30 nm particles and 03 were detected, particularly in spring, indicating that NPF can be attributed to photochemical reactions.

A Comparison of the Physical and Optical Properties of Anthropogenic Air Pollutants and Mineral Dust over Northwest China

Emissions of mineral dust and its mixing with anthropogenic air pollutants affect both regional and global climates. Our fieldwork in late spring 2007（April 25-June 15） measured the physical and optical properties of dust storms mixed with local air pollutants at a rural site about 48 km southeast of central Lanzhou. Levels of air pollutants and aerosol optical properties were observed during the experiment, with concentrations of NOx（6.8 ± 3.3 ppb, average ± standard deviation）, CO（694 ± 486 ppb）, SO2（6.2 ±10 ppb）, O3（50.7 ± 13.1 ppb）, and PM10（172 ± 180 μg m-3）, and aerosol scattering coefficient（164 ±89 Mm-1; 1 Mm = 106m） and absorption coefficient（11.7 ± 6.6 Mm-1）, all much lower than the values observed during air pollution episodes in urban areas. During a major dust storm, the mass concentration of PM10 reached 4072 μg m-3, approximately 21-fold higher than in non-dust storm periods. The mixing ratios of trace gases declined noticeably after a cold front passed through. The observed CO/SO2 and CO/NOx ratios during air pollution episodes were 4.2-18.3 and 13.7-80.5, respectively, compared with the corresponding ratios of 38.1-255.7 and 18.0-245.9 during non-pollution periods. Our investigations suggest that dust storms have a significant influence on air quality in areas far from their source, and this large-scale transport of dust and air pollutants produces major uncertainties in the quantification of the global effects of emissions over Northwest China.

DEVELOPMENT OF THE 2-D COUPLED STRATOSPHERIC-TROPOSPHERIC DYNAMICAL-RADIATIVE-CHEMICAL MODEL—PART Ⅰ:THE DESCRIPTION OF THE MODEL AND ITS PRELIMINARY RESULTS

In this paper,a two-dimensional(2-D)coupled stratospheric-tropospheric dynamical-radiative- chemical model has been developed,and some preliminary results have been given.From these results we can see that the latitude-height distribution characteristics and the seasonal variation of the dynamical fields such as atmospheric temperature,wind field,etc.can be effectively simulated by using this model;and the modelled latitude-height distribution of trace gases gives their distribution characteristics and seasonal variation rather well.All of these are testimony to the strong ability of the model.

Large inter annual variation in air quality during the annual festival ‘Diwali' in an Indian megacity

A network of air quality and weather monitoring stations was established under the System of Air Quality Forecasting and Research（SAFAR） project in Delhi. We report observations of ozone（O_3）, nitrogen oxides（NO_x）, carbon monoxide（CO） and particulate matter（PM_2.5and PM_（10）） before, during and after the Diwali in two consecutive years, i.e., November 2010 and October 2011. The Diwali days are characterised by large firework displays throughout India. The observations show that the background concentrations of particulate matter are between 5 and 10 times the permissible limits in Europe and the United States. During the Diwali-2010, the highest observed PM_（10） and PM_2.5mass concentration is as high as2070 μg/m^3 and 1620 μg/m3, respectively（24 hr mean）, which was about 20 and 27 times to National Ambient Air Quality Standards（NAAQS）. For Diwali-2011, the increase in PM_（10） and PM_2.5mass concentrations was much less with their peaks of 600 and of 390 μg/m^3 respectively, as compared to the background concentrations. Contrary to previous reports,firework display was not found to strongly influence the NO_x, and O_3 mixing ratios, with the increase within the observed variability in the background. CO mixing ratios showed an increase. We show that the large difference in 2010 and 2011 pollutant concentrations is controlled by weather parameters.

REMOTE SENSING OF ATMOSPHERIC CONSTITUENTS AND THE MULTI-FUNCTION SPECTROPHOTOMETER

A multi-functional solar and skylight spectrophotometer has been developed for the study of atmospheric constituents and aerosols. The instrument and its performance are described. Due to telescope structure and lock-in amplification technique adopted,the sensitivity of the instrument is high enough to conduct direct sun moon and twilight measurement for several atmospheric species and the degree of polarization and intensity observation for sky light. From measured results, the total column abundance of atmospheric species and the optical characteristics of aerosol can be retrieved. In this paper, the daily averaged column abundance of O_3 measured in Beijing by direct sun was compared with Dobson spectrophotometer nearby. The two did not show significant difference.

DETERMINATION OF GASEOUS COMPOSITION IN THE MIDDLE ATMOSPHERE BY USING HIGH SPECTRAL RESOLUTION METHODS

One of the crucial problems in study on the middle atmosphere is to determine the concentration and distribution of some trace gases.In this aspect,sounding methods with high spectral resolution have been developed by many scientists.Some major trace gases and their spectral characteristics,space-borne limb method for determination of trace gases in the middle atmosphere are introduced,requirements for used methods and instruments,development and challenge encountered by sounding of trace gases with high spectral resolution are discussed in this paper.

Satellite record of the transition of air quality over China

The rapid development of atmospheric satellite instruments since 1990s provides unprecedented large amount of observational datasets concerning global atmospheric pollutants.The continu-ous and long-term large-scale satellite products such as aerosol optical depth,tropospheric NO 2 and SO 2 enable effective and objective evaluation of air quality.Satellite columnar aerosol opti-cal parameters can be used to indicate particle pollution near surface after correction.By contrast,satellite results of trace gas pollutants such as NO 2 and SO 2 from fossil fuel combustion with short lifetime around half one day are used to estimate anthro-pogenic emissions.It is shown that the overall anthropogenic emissions in China have largely declined since strict emission reduction policy implemented since 2013.However,coarse pixel resolution of the trace gases,limited information and retrieval bias of aerosol properties tend to hinder further application of satellite in air quality research.Recently launched satellite missions with advanced detection abilities will greatly enhance global atmo-spheric observations with much more datasets available.