Under the background of global warming,the summer temperature of the North and Northeast China(NNEC)has significantly increased since 2017,which was accompanied by the aggravated ozone(O_(3))pollution.In 2018,the NNEC...Under the background of global warming,the summer temperature of the North and Northeast China(NNEC)has significantly increased since 2017,which was accompanied by the aggravated ozone(O_(3))pollution.In 2018,the NNEC experienced a record-breaking summer of the past 40 years.Influenced by the abnormal high temperatures,a regional ozone event occurred on 2-3 August,over 63%of 79 selected cities in the NNEC were exposed to O_(3)pollution,and the maximum value of MDA8 O_(3)reached 268μg/m 3.Observations indicated that ozone concentrations agree well with the maximum temperature at 2 meters(MT2M)over NNEC with a correlation coefficient of 0.69.During the pollution episode,strong downdraft in the local high(35°N-42.5°N,112.5°E-132.5°E;LH)over the NNEC created the favourable meteorological conditions for O_(3)formation.By analyzing the horizontal wind and wave activity fluxes(WAFs)at 200 h Pa,we found that the LH formation was resulted from the Rossby wave propagation from upstream along the mid-latitude Asian jet.The split polar vortex intrusion further strengthened the amplitude of the Rossby wave and reinforced the LH.Moreover,a secondary circulation between Typhoon Jongdari and the LH contributed to the enhanced LH with strong subsidence.On the other hand,the stratospheric intrusions under the deep subsidence also contributed to the enhanced surface O_(3).In this study,the deep-seated meteorological dynamical mechanisms contributing to the abnormal high temperatures were investigated,which can lead to a better understanding of the regional O_(3)pollution over NNEC under the global-warming background.展开更多
Objective Previous studies indicate that the North China Craton（NCC）had undergone the loss of thickened lithosphere and fundamental change of physical and chemical property of lithospheric mantle（the destruction of...Objective Previous studies indicate that the North China Craton（NCC）had undergone the loss of thickened lithosphere and fundamental change of physical and chemical property of lithospheric mantle（the destruction of NCC）during the Mesozoic.The peak period of the destruction of NCC is estimated to be 130 Ma,accompanied by widespread metamorphic core complex,rift basins,A-type granites and mafic dykes. However, it remains greatly controversial on the tectonic setting of NCC in the pre- 130Ma.展开更多
基金partially supported by the grant of the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA19020303)the National Key R and D Plan(Quantitative Relationship and Regulation Principle between Regional Oxidation Capacity of Atmospheric and Air Quality(No.2017YFC0210003)+1 种基金the National Natural Science Foundation of China(No.41505133)the Beijing Major Science and Technology Project 510(No.Z181100005418014)。
文摘Under the background of global warming,the summer temperature of the North and Northeast China(NNEC)has significantly increased since 2017,which was accompanied by the aggravated ozone(O_(3))pollution.In 2018,the NNEC experienced a record-breaking summer of the past 40 years.Influenced by the abnormal high temperatures,a regional ozone event occurred on 2-3 August,over 63%of 79 selected cities in the NNEC were exposed to O_(3)pollution,and the maximum value of MDA8 O_(3)reached 268μg/m 3.Observations indicated that ozone concentrations agree well with the maximum temperature at 2 meters(MT2M)over NNEC with a correlation coefficient of 0.69.During the pollution episode,strong downdraft in the local high(35°N-42.5°N,112.5°E-132.5°E;LH)over the NNEC created the favourable meteorological conditions for O_(3)formation.By analyzing the horizontal wind and wave activity fluxes(WAFs)at 200 h Pa,we found that the LH formation was resulted from the Rossby wave propagation from upstream along the mid-latitude Asian jet.The split polar vortex intrusion further strengthened the amplitude of the Rossby wave and reinforced the LH.Moreover,a secondary circulation between Typhoon Jongdari and the LH contributed to the enhanced LH with strong subsidence.On the other hand,the stratospheric intrusions under the deep subsidence also contributed to the enhanced surface O_(3).In this study,the deep-seated meteorological dynamical mechanisms contributing to the abnormal high temperatures were investigated,which can lead to a better understanding of the regional O_(3)pollution over NNEC under the global-warming background.
基金financially supported by the Nature Science Foundation of China (grants No.41372109,90914003 and 41672111)China Geological Survey (grants No.12120115068901,1212011120142 and 12120114064301)the National Science and Technology Works Special Project (grant No.2015FY310100)
文摘Objective Previous studies indicate that the North China Craton（NCC）had undergone the loss of thickened lithosphere and fundamental change of physical and chemical property of lithospheric mantle（the destruction of NCC）during the Mesozoic.The peak period of the destruction of NCC is estimated to be 130 Ma,accompanied by widespread metamorphic core complex,rift basins,A-type granites and mafic dykes. However, it remains greatly controversial on the tectonic setting of NCC in the pre- 130Ma.
