Using a detailed, fully coupled chemistry climate model （CCM）, the effect of increasing stratospheric H20 on ozone and temperature is investigated. Different CCM time-slice runs have been performed to investigate th...Using a detailed, fully coupled chemistry climate model （CCM）, the effect of increasing stratospheric H20 on ozone and temperature is investigated. Different CCM time-slice runs have been performed to investigate the chemical and radiative impacts of an assumed 2 ppmv increase in H20. The chemical effects of this H20 increase lead to an overall decrease of the total column ozone （TCO） by ～1% in the tropics and by a maximum of 12% at southern high latitudes. At northern high latitudes, the TCO is increased by only up to 5% due to stronger transport in the Arctic. A 2-ppmv H2O increase in the model＇s radiation scheme causes a cooling of the tropical stratosphere of no more than 2 K, but a cooling of more than 4 K at high latitudes. Consequently, the TCO is increased by about 2%-6%. Increasing stratospheric H2O, therefore, cools the stratosphere both directly and indirectly, except in the polar regions where the temperature responds differently due to feedbacks between ozone and H2O changes. The combined chemical and radiative effects of increasing H2O may give rise to more cooling in the tropics and middle latitudes but less cooling in the polar stratosphere. The combined effects of H2O increases on ozone tend to offset each other, except in the Arctic stratosphere where both the radiative and chemical impacts give rise to increased ozone. The chemical and radiative effects of increasing H2O cause dynamical responses in the stratosphere with an evident hemispheric asymmetry. In terms of ozone recovery, increasing the stratospheric H2O is likely to accelerate the recovery in the northern high latitudes and delay it in the southern high latitudes. The modeled ozone recovery is more significant between 2000 ～2050 than between 2050～2100, driven mainly by the larger relative change in chlorine in the earlier period.展开更多
Siberian wildfires are pivotal in determining the carbon cycle and climate dynamics,exerting a profound impact on the ecosystems of the entire Arctic region.Over the past few decades,variations in summer precipitation...Siberian wildfires are pivotal in determining the carbon cycle and climate dynamics,exerting a profound impact on the ecosystems of the entire Arctic region.Over the past few decades,variations in summer precipitation in West Siberia have significantly influenced wildfire activity.This study analyzed precipitation trends in West Siberia from 1982 to 2021 using observations and transient simulations,uncovering a strong correlation between precipitation variability and ozone concentrations in the upper troposphere-lower stratosphere(UTLS).Heightened UTLS ozone levels warm the upper atmosphere over West Siberia during summer.This warming modifies the regional polar jet stream,intensifying its southern branch and weakening the northern one,leading to a southward shift in the jet stream.Consequently,cyclonic circulation anomalies emerge in the upper troposphere,characterized by a barotropic structure with unusual upward movements around 60°N.This upward motion triggers corresponding anomalies in zonal winds in the lower troposphere,fostering a low-pressure system at the surface.This atmospheric shift results in an influx of warm,moist air from the south and cold,dry air from the north into Siberia,enhancing cloud formation and precipitation.Notably,our analysis suggests that the rise in summer precipitation in West Siberia between 1993 and 2010 is linked to increased UTLS ozone concentrations during this period.Conversely,the decline in UTLS ozone since 2010 may increase the risk of wildfires by suppressing precipitation.Our findings underscore the pivotal role of stratospheric chemistry in shaping the regional climate and wildfire behavior.展开更多
The Arctic has experienced several extreme springtime stratospheric ozone depletion events over the past four decades,particularly in 1997,2011 and 2020.However,the impact of this stratospheric ozone depletion on the ...The Arctic has experienced several extreme springtime stratospheric ozone depletion events over the past four decades,particularly in 1997,2011 and 2020.However,the impact of this stratospheric ozone depletion on the climate system remains poorly understood.Here we show that the stratospheric ozone depletion causes significant reductions in the sea ice concentration(SIC)and the sea ice thickness(SIT)over the Kara Sea,Laptev Sea and East Siberian Sea from spring to summer.This is partially caused by enhanced ice transport from Barents-Kara Sea and East Siberian Sea to the Fram Strait,which is induced by a strengthened and longer lived polar vortex associated with stratospheric ozone depletion.Additionally,cloud longwave radiation and surface albedo feedbacks enhance the melting of Arctic sea ice,particularly along the coast of the Eurasian continent.This study highlights the need for realistic representation of stratosphere-troposphere interactions in order to accurately predict Arctic sea ice loss.展开更多
基金supported by National Natural Science Foundation of China (Grant Nos. 40575019, 40730949)the U.K. Natural Environ-ment Research Council (NERC)
文摘Using a detailed, fully coupled chemistry climate model （CCM）, the effect of increasing stratospheric H20 on ozone and temperature is investigated. Different CCM time-slice runs have been performed to investigate the chemical and radiative impacts of an assumed 2 ppmv increase in H20. The chemical effects of this H20 increase lead to an overall decrease of the total column ozone （TCO） by ～1% in the tropics and by a maximum of 12% at southern high latitudes. At northern high latitudes, the TCO is increased by only up to 5% due to stronger transport in the Arctic. A 2-ppmv H2O increase in the model＇s radiation scheme causes a cooling of the tropical stratosphere of no more than 2 K, but a cooling of more than 4 K at high latitudes. Consequently, the TCO is increased by about 2%-6%. Increasing stratospheric H2O, therefore, cools the stratosphere both directly and indirectly, except in the polar regions where the temperature responds differently due to feedbacks between ozone and H2O changes. The combined chemical and radiative effects of increasing H2O may give rise to more cooling in the tropics and middle latitudes but less cooling in the polar stratosphere. The combined effects of H2O increases on ozone tend to offset each other, except in the Arctic stratosphere where both the radiative and chemical impacts give rise to increased ozone. The chemical and radiative effects of increasing H2O cause dynamical responses in the stratosphere with an evident hemispheric asymmetry. In terms of ozone recovery, increasing the stratospheric H2O is likely to accelerate the recovery in the northern high latitudes and delay it in the southern high latitudes. The modeled ozone recovery is more significant between 2000 ～2050 than between 2050～2100, driven mainly by the larger relative change in chlorine in the earlier period.
基金supported by the National Natural Science Foundation of China(42122037,42130601,42375070,42105016,and42275084)。
文摘Siberian wildfires are pivotal in determining the carbon cycle and climate dynamics,exerting a profound impact on the ecosystems of the entire Arctic region.Over the past few decades,variations in summer precipitation in West Siberia have significantly influenced wildfire activity.This study analyzed precipitation trends in West Siberia from 1982 to 2021 using observations and transient simulations,uncovering a strong correlation between precipitation variability and ozone concentrations in the upper troposphere-lower stratosphere(UTLS).Heightened UTLS ozone levels warm the upper atmosphere over West Siberia during summer.This warming modifies the regional polar jet stream,intensifying its southern branch and weakening the northern one,leading to a southward shift in the jet stream.Consequently,cyclonic circulation anomalies emerge in the upper troposphere,characterized by a barotropic structure with unusual upward movements around 60°N.This upward motion triggers corresponding anomalies in zonal winds in the lower troposphere,fostering a low-pressure system at the surface.This atmospheric shift results in an influx of warm,moist air from the south and cold,dry air from the north into Siberia,enhancing cloud formation and precipitation.Notably,our analysis suggests that the rise in summer precipitation in West Siberia between 1993 and 2010 is linked to increased UTLS ozone concentrations during this period.Conversely,the decline in UTLS ozone since 2010 may increase the risk of wildfires by suppressing precipitation.Our findings underscore the pivotal role of stratospheric chemistry in shaping the regional climate and wildfire behavior.
基金supported by Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(SML2021SP312)the National Natural Science Foundation of China(4207506242130601,and 41922044)+3 种基金the National Key Research&Development Program of China(2018YFC1506003)the Fundamental Research Funds for the Central Universities,China(lzujbky-2021ey04)Young Doctoral Funds for Gansu Provincial Education Department(2021QB-009)supported by Supercomputing Center of Lanzhou University。
文摘The Arctic has experienced several extreme springtime stratospheric ozone depletion events over the past four decades,particularly in 1997,2011 and 2020.However,the impact of this stratospheric ozone depletion on the climate system remains poorly understood.Here we show that the stratospheric ozone depletion causes significant reductions in the sea ice concentration(SIC)and the sea ice thickness(SIT)over the Kara Sea,Laptev Sea and East Siberian Sea from spring to summer.This is partially caused by enhanced ice transport from Barents-Kara Sea and East Siberian Sea to the Fram Strait,which is induced by a strengthened and longer lived polar vortex associated with stratospheric ozone depletion.Additionally,cloud longwave radiation and surface albedo feedbacks enhance the melting of Arctic sea ice,particularly along the coast of the Eurasian continent.This study highlights the need for realistic representation of stratosphere-troposphere interactions in order to accurately predict Arctic sea ice loss.
