Gao Jixi

Typical Ecotones in China

Abstract: An ecotone is a transition area between two biomes or two different ecosystems and are often fragile, sensitive and variable. Since the 1970s, the study of the ecotone has increasingly gained notoriety as an important facet of ecological research. China, with a vast complex geology, climate and vegetation, is home to a variety of ecotones. This variety is witnessed in breeds, scales and sizes. This vast array has not only laid a solid foundation for scientific research but also enhanced Chinas economic development, social development and cultural diversity conservation. According to the geographical distribution and ecological features of Chinas large scale ecotone, “The trinity index system” has been established including land use types, natural climate characteristics and agricultural economic development to classify and define the spatial distribution of typical ecotones in China. Based on this classification, the natural environmental characteristics, environmental fragility and the existing problems of five kinds of typical ecotones have been studied. This study will lead to a comprehensive understanding of the evolutionary patterns of ecotones.

石家庄市冬季PM 2.5 污染特征、成因及潜在源区分析

对石家庄市2016年1月18-22日出现的PM2.5污染过程进行研究，选择3个不同地区采用中流量采样器分别采集PM2.5和PM10样品，测定PM2.5质量浓度及其化学组分（含碳组分、水溶性离子和无机元素），分析PM2.5污染天气的污染特征和引起污染的气象因素，结合后向轨迹模型（HYSPLIT）分析污染的主要潜在源区。结果显示，在采样期间3个点的PM2.5平均质量浓度分别为113、131和119 μg·m-3，PM2.5浓度高值出现在早晨和午夜，冬季京津冀地区农村散煤燃烧也是大气污染的主要原因。有机碳（OC）最大质量浓度值为218.37 μg·m-3，无机碳（EC）最大质量浓度值为21.22 μg·m-3。污染过程中3个点的地壳元素（Na、Ca、Mg、Al、K和Fe）质量浓度变化范围为27.19~60.03 μg·m-3，占总无机元素的96.5%，表明交通源、道路扬尘和煤炭燃烧是此次石家庄市PM2.5污染的主要贡献源类。较高的相对湿度和弱风速也会加速二次粒子的生成和颗粒物吸湿增长。潜在源分析表明，石家庄市PM2.5污染主要受来源于北京和天津的气团影响，同时潜在源贡献（PSCF）分析表明河北省是影响石家庄市环境空气质量的最主要潜在源区。