检索结果-南通市图书馆

Influence of meteorological factors on open biomass burning at a background site in Northeast China

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第4期138卷 1-9页

作者： Yulong Wang Linlin Liang Wanyun Xu Chang Liu Hongbing Cheng Yusi Liu Gen Zhang Xiaobin Xu Dajiang Yu Peng Wang Qingli Song Jiumeng Liu Yuan Cheng State Key Laboratory of Urban Water Resource and Environment School of EnvironmentHarbin Institute of TechnologyHarbin 150090China State Key Laboratory of Severe weather&Key Laboratory for Atmospheric Chemistry Chinese Academy of Meteorological SciencesBeijing 100081China Longfengshan Regional Background Station China Meteorological AdministrationHeilongjiang 150200China heilongjiang Climate Center Heilongjiang 150030China

Biomass burning(BB)is a very important emission source that significantly adversely impacts regional air *** produces a large number of primary organic aerosol(POA)and black carbon(BC).Besides,BB also provides many precursors for secondary organic aerosol(SOA)*** this work,the ratio of levoglucosan(LG)to organic carbon(OC)and the fire hotspots map was used to identify the open biomass burning(OBB)events,which occurred in two representative episodes,October 13 to November 30,2020,and April1 to April 30,*** ratio of organic aerosol(OA)to reconstructed PM_(2.5)concentration(PM_(2.5)^(*))increased with the increase of LG/*** LG/OC ratio is higher than 0.03,the highest OA/PM_(2.5)^(*)ratio can reach 80%,which means the contribution of OBB to OA is *** to the ratio of LG to K^(+),LG to mannosan(MN)and the regional characteristics of Longfengshan,it can be determined that the crop residuals are the main *** occurrence of OBB coincides with farmers’preferred choices,i.e.,burning biomass in“bright weather”.The“bright weather”refers to the meteorological conditions with high temperature,low humidity,and without *** factors indirectly affect regional biomass combustion pollution by influencing farmers’active choices.

关键词： Air pollution Biomass burning Meteorological factors Organic trace Agricultural fires

Observations of Cloud Condensation Nuclei in North China

在线全文

学校读者我要写书评

暂无评论

Acta meteorologica Sinica 2008年第1期22卷 97-106页

作者：石立新段英 weather modification office of Hebei province

Using a DMT （Droplet Measurement Technologies） continuous flow streamwise thermal gradient cloud condensation nuclei （CCN） counter mounted on a Cheyenne IIIA aircraft, about 20 flights for aircraft mea- surements of CCN over North China were conducted in the autumn of 2005 and spring of 2006. According to the design for aircraft observation, the method of spiral ascent or descent in the troposphere was used for the vertical measurement of CCN, and some certain levels were chosen for horizontal measurement. The vertical distributions of CCN concentrations show that most CCN particles are concentrated in the low level of troposphere and CCN concentration decreased with height increasing. It suggests that the main source of CCN is from the surface. This result is consistent with former studies during 1983-1985 in China with a static thermal gradient CCN counter. The comparison of vertical observations between polluted rural area near Shijiazhuang and non-polluted rural area near Zhangjiakou shows that there is about five times difference in CCN concentration. But over two polluted cities, Shijiazhuang and Handan, there is no notable difference in CCN concentration. The horizontal flight measurements for penetrating the cumulus clouds experiment show the apparent decrease of CCN in clouds. It confirms that cloud has a definite consumptive effect on CCN particles because some CCN particles can form cloud droplets. The surface measurements of CCN in Shijiazhuang City were made during June-August 2005. The statistical CCN data show the great difference in concentration at the same supersaturation （S） in Shijiazhuang summertime. The minimum CCN concentrations were 584, 808, and 2431 cm-3, and the maximum concentrations were 9495, 16332, and 21812 cm-3 at S=0.1%, 0.3%, and 0.5%, respectively. CCN has a diurnal variation cycle. From 0600 BT, the concentration began to increase and reached the maximum at about noon. Then it generally decreased throughout the afternoon. The re

关键词： North China cloud condensation nuclei (CCN) observation

Microphysical Properties of Convective Clouds in Summer over the Tibetan Plateau from SNPP/VIIRS Satellite Data

在线全文

学校读者我要写书评

暂无评论

Journal of Meteorological Research 2019年第3期33卷 433-445页

作者： Zhiguo YUE Xing YU Guihua LIU Jin DAI Yannian ZHU Xiaohong XU Ying HUI Chuang CHEN Meteorological Institute of Shaanxi province Xi'an 710014 office of weather modification of Shaanxi province Xi'an 710014

The Tibetan Plateau (TP) plays an important role in formation and development of the East Asian atmospheric circulation, climate variability, and disastrous weathers in China. Among the many topics on TP meteorology, it is critical to understand the microphysical characteristics of clouds over the TP;however, observations of the cloud microphysics in this area are insufficient mainly due to sparse stations and limited cloud physical data. The Visible Infrared Imaging Radiometer Suite (VⅡRS), onboard the Suomi National Polar-orbiting Partnership (SNPP) satellite, has an improved imaging spectroradiometer with 17 channels of 750-m moderate resolution and 5 channels of 375-m image resolution. The high-resolution instrument has an advantage for observing the small or initial convective clouds. Based on the methodologies that we proposed before for retrieving cloud microphysical properties from SNPP, an automated mapping software package named Automatic Mapping of Convective Clouds (AMCC) has been developed at the scale of satellite swath. The properties of convective clouds are retrieved by AMCC and their values are averaged over 0.33°×0.33° grids based on the SNPP/VⅡRS satellite data over the TP during the summers of 2013-17. The results show that:(1) the temperature of lifting condensation level (TLCL) at Naqu meteorological station and the cloud base temperature (Tb) retrieved from VⅡRS are linearly correlated, with a correlation coefficient of 0.87 and standard deviation (STD) of 3.0℃;(2) convective clouds over the TP have the following macro-and microphysical properties. First, the cloud base temperature (Tb) is about -5℃, the cloud base height above the ground (Hb) ranges between 1800 and 2200 m, and the cloud water content is low. Second, the cloud condensation nuclei concentration (NCCN) is between 200 and 400 mg-1 with 0.7% in maximum supersaturation (Smax);consequently, the condensation growth of water cloud droplet with less NCCN and higher Smax is fast. Thir

关键词： Tibetan Plateau Visible Infrared Imaging Radiometer Suite (VⅡRS) retrieval of cloud microphysical properties convective cloud cloud base temperature cloud condensation nuclei

ESTIMATION OF ARTIFICIAL PRECIPITATION ENHANCEMENT RESOURCE CONDITION AND CLOUD SEEDING POTENTIAL BY GROUND-BASED REMOTE SENSING DATA

在线全文

学校读者我要写书评

暂无评论

Acta meteorologica Sinica 1999年第1期13卷 103-114页

作者：段英 weather modification office of Hebei province Shijiazhuang 050021

In this paper,the data of continuous atmospheric vertical integral vapour and liquid water content during April-June of 1992-1994 obtained by a ground-based dual-channel microwave radiometer are used to analyse the statistical characteristics of atmospheric vapour and liquid water content,and the relative distribution characteristics of vapour and liquid water content in cloudy atmosphere,the correlative relation of integral liquid water content L and ground precipitation intensity *** precipitation transform rate of precipitation ***,the weather modification condition of precipitus stratiform clouds and seeding potential is analyzed and discussed.

关键词： ground-based remote-sensing artificial precipitation enhancement resource condition seeding potential

Shape Classification of Cloud Particles Recorded by the 2D-S Imaging Probe Using a Convolutional Neural Network

在线全文

学校读者我要写书评

暂无评论

Journal of Meteorological Research 2023年第4期37卷 521-535页

作者： Rong ZHANG Haixia XIAO Yang GAO Haizhou SU Dongnan LI Lei WEI Junxia LI Hongyu LI Cloud–Precipitation Physics and weather modification Key Laboratory(CPML) China Meteorological AdministrationBeijing 100081 CMA weather modification Centre China Meteorological Administration(CMA)Beijing 100081 Key Laboratory of Transportation Meteorology of China Meteorological Administration Nanjing Joint Institute for Atmospheric SciencesNanjing 210041 heilongjiang weather modification office Harbin 150030

The airborne two-dimensional stereo(2D-S) optical array probe has been operating for more than 10 yr, accumulating a large amount of cloud particle image data. However, due to the lack of reliable and unbiased classification tools,our ability to extract meaningful morphological information related to cloud microphysical processes is limited. To solve this issue, we propose a novel classification algorithm for 2D-S cloud particle images based on a convolutional neural network(CNN), named CNN-2DS. A 2D-S cloud particle shape dataset was established by using the 2D-S cloud particle images observed from 13 aircraft detection flights in 6 regions of China(Northeast, Northwest, North,East, Central, and South China). This dataset contains 33,300 cloud particle images with 8 types of cloud particle shape(linear, sphere, dendrite, aggregate, graupel, plate, donut, and irregular). The CNN-2DS model was trained and tested based on the established 2D-S dataset. Experimental results show that the CNN-2DS model can accurately identify cloud particles with an average classification accuracy of 97%. Compared with other common classification models [e.g., Vision Transformer(ViT) and Residual Neural Network(ResNet)], the CNN-2DS model is lightweight(few parameters) and fast in calculations, and has the highest classification accuracy. In a word, the proposed CNN-2DS model is effective and reliable for the classification of cloud particles detected by the 2D-S probe.

关键词： cloud particles particle shape 2D-S probe shape classification convolutional neural network

Macro-and Micro-physical Characteristics of Different Parts of Mixed Convective-stratiform Clouds and Differences in Their Responses to Seeding

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2022年第12期39卷 2040-2055页

作者： Dejun LI Chuanfeng ZHAO Peiren LI Cao Liu Dianli GONG Siyao LIU Zhengteng YUAN Yingying CHEN Hubei Meteorological Service Center Wuhan 430205China College of Global Change and Earth System Science Beijing Normal UniversityBeijing 100875China weather modification office of Shanxi province Taiyuan 030032China Wuhan Central Meteorological Observatory Wuhan 430074China weather modification office of Shandong province Jinan 250031China

This study investigates the cloud macro-and micro-physical characteristics in the convective and stratiform regions and their different responses to the seeding for mixed convective-stratiform clouds that occurred in Shandong province on 21 May 2018,based on the observations from the aircraft,the Suomi National Polar-Orbiting Partnership(NPP)satellite,and the high-resolution Himawari-8(H8)*** aircraft observations show that convection was deeper and radar echoes were significantly enhanced with higher tops in response to seeding in the convective *** is linked with the conversion of supercooled liquid droplets to ice crystals with released latent heat,resulting in strengthened updrafts,enhanced radar echoes,higher cloud tops,and more and larger precipitation *** contrast,in the stratiform cloud region,after the Silver Iodide(AgI)seeding,the radar echoes become significantly weaker at heights close to the seeding layer,with the echo tops lowered by 1.4–1.7 *** addition,a hollow structure appears at the height of 6.2–7.8 km with a depth of about 1.6 km and a diameter of about 5.5 km,and features such as icing seeding tracks *** suggest that the transformation between droplets and ice particles was accelerated by the seeding in the stratiform *** NPP and H8 satellites also show that convective activity was stronger in the convective region after seeding;while in the stratiform region,a cloud seeding track with a width of 1–3 km appears 10 km downstream of the seeding layer 15 minutes after the AgI seeding,which moves along the wind direction as width increases.

关键词： airborne Ka-band Precipitation Radar(KPR) mixed convective-stratiform clouds convective region stratiform region cloud seeding cloud microphysical properties

A possible way to extract a stationary relationship between ENSO and the East Asian winter monsoon

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2020年第4期13卷 294-300页

作者： FAN Genchang LV Feng ZHANG Jinglong FU Jiao weather modification office Hebei Province Meteorological BureauShijiazhuangChina Climate Center Hebei Province Meteorological BureauShijiazhuangChina

Previous studies have revealed that the relationship between the El Niño-Southern Oscillation(ENSO)and the East Asian winter monsoon(EAWM)is not statistically significant when the Pacific Decadal Oscillation(PDO)is in its positive *** study explores a possible way to obtain a robust ENSO-EAWM relationship from a dynamical point of ***,the authors show that the East Asian winter temperature is significantly and continuously correlated with ENSO when the linear impact of the PDO has been linearly removed from *** a conclusion is confirmed by different reanalysis *** dynamical process intensifying the ENSO-EAWM is further investigated from the perspective of whether or not the atmospheric teleconnection between the Pacific and East Asia has *** to the situation associated with the original ENSO in the positive phase of the PDO,the Walker circulation associated with the processed ENSO,from which the effect of North Pacific climate systems has been removed,tends to exert a more pronounced influence on the atmospheric circulation over the western North ***,an anomalous anticyclone emerges in the Kuroshio *** this sense,the Pacific-East Asian teleconnection is also well established during the positive phase of the PDO,which favors the impact of ENSO on East Asian winter temperature.

关键词： ENSO Pacific Decadal Oscillation East Asia winter monsoon temperature

Observations and Modeling of Ice Water Content in a Mixed-Phase Cloud System

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2013年第4期6卷 210-215页

作者： HOU Tuan-Jie LEI Heng-Chi HU Zhao-Xia FENG Qiu-Juan Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric PhysicsChinese Academy of Sciences weather modification office of Shanxi province

The ice water content(IWC) distribution in a mixed-phase cloud system was investigated using Cloud-Sat data,aircraft measurements,and the weather Research and Forecasting(WRF) *** precipitation and IWC were in general agreement with rain gauge,sat-ellite,and aircraft *** cloud case was char-acterized by a predominant cold layer and high IWC throughout the cloud-development and precipitation *** CloudSat-retrieved products suggested that the IWC was distributed from 4.0 to 8.0 km,with the maximum values(up to 0.5 g m-3) at 5.0-6.0 km at the earlymature stage of cloud *** IWC(up to 0.8 g m-3) was also detected by airborne probes at 4.2 and 3.6 km at the late-mature *** WRF model simulation re-vealed that the predominant riming facilitated rapid ac-cumulation of high IWC at 3.0-6.0 km.

关键词： aircraft observation ice water content WRF

Plasma characteristics in the discharge region of a 20A emission current hollow cathode

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2018年第2期20卷 148-155页

作者：孙明明张天平温晓东郭伟龙宋嘉尧 Science and Technology on Vacuum Technology and Physics Laboratory Lanzhou Institute of Physics Lanzhou 730000 People's Republic of China weather modification office of Shaanxi province Xi'an 710014 People's Republic of China

Numerical calculation and fluid simulation methods were used to obtain the plasma characteristics in the discharge region of the LIPS-300 ion thruster’s 20 A emission current hollow cathode and to verify the structural design of the *** results of the two methods indicated that the highest plasma density and electron temperature,which improved significantly in the orifice region,were located in the discharge region of the hollow *** magnitude of plasma density was about 10^21m^-3in the emitter and orifice regions,as obtained by numerical calculations,but decreased exponentially in the plume region with the distance from the orifice ***,compared to the emitter region,the electron temperature and current improved by about 36%in the orifice *** hollow cathode performance test results were in good agreement with the numerical calculation results,which proved that that the structural design of the emitter and the orifice met the requirements of a 20 A emission *** numerical calculation method can be used to estimate plasma characteristics in the preliminary design stage of hollow cathodes.

关键词： ion thruster hollow cathode plasma characteristics