摘要
利用2000年12月—2023年12月卫星遥感反演的气溶胶光学厚度逐日资料,结合2023年每日中午地面观测蓝天资料,基于气溶胶光学厚度得到的蓝天等级监测指标,分析2000-2023年京津冀地区蓝天日数的时空变化特征及其变化趋势.结果表明:2001-2023年京津冀蓝天日数年平均值分别为144.2 d·a-1、96.3 d·a-1和119.6 d·a-1,北京蓝天日数最多,河北次之,天津最少.空间分布上,河北北部年平均蓝天日数最多,河北南部蓝天日数最少.京津冀蓝天日数具有明显季节变化,冬季和秋季蓝天日数最多,春季次之,夏季最少.2001-2023年京津冀蓝天日数年平均值均呈显著增加趋势,每10年分别增加18.1 d、22.3 d和16.3 d,其中2001-2013年无显著趋势变化,2013-2023年呈增加趋势,每10年分别增加26.9 d、46.5 d和36.4 d.
Abstract
Blue sky often represents better air quality and lower air pollution.Using satellite aerosol optical depth(AOD)data of Beijing,Tianjin and Hebei Province from 2000 to 2023,combined with the blue-sky data observed at noon time in 2023,a blue-sky grade index is established based on satellite AOD,in which the monitoring index of blue-sky grade is the AOD at 550 nm less than 0.36,and that of deep blue-sky grade is the AOD at 550 nm less than 0.2.Spatial and temporal characteristics of blue-sky grade days in Beijing-Tianjin-Hebei Region from 2000 to 2023 are investigated.Results show that the multi-year average blue-sky days in Beijing,Tianjin,and Hebei are 144.2 d·a-1,96.3 d·a-1,and 119.6 d·a-1,respectively,with the highest number of blue-sky days for Beijing,followed by Hebei and the lowest number is recorded in Tianjin.In terms of spatial distribution,the northern part of Hebei has the highest annual average of blue-sky days,while the south-ern part of Hebei has the lowest number of blue-sky days.The number of blue-sky days in Beijing-Tianjin-Hebei exhibits noticeable seasonal changes,with the highest number of blue-sky days in winter and au-tumn,followed by spring,and the lowest in summer.From 2001 to 2023,the average annual number of clear-sky days in Beijing,Tianjin,and Hebei takes on an increasing trend,with an increase of 18.1 d,22.3 d and 16.3 d per decade,respectively.There is no significant trend change from 2001 to 2013.However,the annual average blue-sky days in Beijing-Tianjin-Hebei from 2013 to 2023 all show increasing trends,with increments of 26.9 d,46.5 d,and 36.4 d per decade,respectively.The annual average blue-sky days and deep blue-sky days in Beijing-Tianjin-Hebei from 2013 to 2023 are higher than those in 2001-2013,with the annual average blue-sky days in Beijing,Tianjin,and Hebei of 153.5 d,107.5 d,and 128.5 d,respectively,which are 17.5 d,21.8 d,and 16.9 d higher than those in 2001-2013.It may be largely due to the implementation of regional air pollution pre-vention and control measures,which have led to a reduction in atmospheric particulate matter concentra-tion since 2013.
维普
万方数据