Observational study of the physical and chemical characteristics of the winter radiation fog in the tropical rainforest in Xishuangbanna, China  

作　　者：Yuan WANG Shengjie NIU Chunsong LU Jingjing LV Jing ZHANG Hongwei ZHANG Sirui ZHANG Naifu SHAO Wei SUN Yuchen JIN Qinghai SONG 

机构地区：[1]Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,and Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration,Nanjing University of Information Science&Technology(NUIST),Nanjing 210044,China [2]College of Safety Science and Engineering,Nanjing Tech University,Nanjing 210009,China [3]Key Laboratory of Tropical Forest Ecology(TFE),Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences(CAS),Menglun 666303,China [4]Henan Meteorological Observation and Data Center,Zhengzhou 450003,China

出　　处：《Science China Earth Sciences》2021年第11期1982-1995,共14页中国科学（地球科学英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Grant Nos.41775134,41822504,41675136,and 41671209);the Innovative Project of Postgraduates in Jiangsu Province(Grant Nos.KYCX20_0920).

摘　　要：We conducted a three-month field experiment focusing on the physical and chemical characteristics of fog in a tropical rainforest in Xishuangbanna,Southwest China,in the winter of 2019.In general,the fog would form at midnight and persist because of the increased long-wave radiative cooling combined with the high relative humidity,gentle breeze,and a relatively low aerosol number concentration in the forest;the fog would dissipate before noon due to the increasing turbulence near the surface.This diurnal cycle is typical for radiation fog.The microphysical fog properties included a relatively low number concentration of the fog droplet,large droplet size,high liquid water content,narrow droplet number-size distribution,and high supersaturation.The chemical properties showed that the fog water was slightly alkaline with low electrical conductivity,whereas the highest proportions of anions and cations therein were Cl^(−)and Ca^(2+),respectively;the chemical components were enriched in small fog droplets.In addition,we indirectly calculated the fog supersaturation according to theκ-Köhler theory.We found that condensation broadens the droplet number-size distribution at relatively low supersaturation,which is positively correlated with the fog-droplet number concentration and negatively correlated with the droplet mean-volume diameter;this affects the key microphysical processes of fog.

关 键 词：Radiation fog Formation and disappearance mechanisms Physical and chemical characteristics SUPERSATURATION Tropical rainforest 

分 类 号：S718.5[农业科学—林学]