Comprehensive air quality model with extensions(CAMx)-decoupled direct method(DDM)was used to simulate ozone-NO_(x)-VOCs sensitivity of for May-November in 2016-2018 in China.Based on the relationship between the simu...Comprehensive air quality model with extensions(CAMx)-decoupled direct method(DDM)was used to simulate ozone-NO_(x)-VOCs sensitivity of for May-November in 2016-2018 in China.Based on the relationship between the simulated ozone(O_(3))sensitivity values and the ratio of formaldehyde(HCHO)to NO_(2)(FNR)and the ratio of production rate of hydrogen peroxide(H_(2)O_(2))to production rate of nitric acid(HNO_(3))(P_(H_(2)O_(2))/P_(HNO_(3))),the localized range of FNR and P_(H_(2)O_(2))/P_(HNO_(3))thresholds in different regions in China were obtained.The overall simulated FNR values are about 1.640-2.520,and P_(H_(2)O_(2))/P_(HNO_(3))values are about 0.540-0.830 for the transition regime.Model simulated O_(3)sensitivities or region specific FNR or P_(H_(2)O_(2))/P_(HNO_(3))thresholds should be applied to ensure the accurate local O3 sensitivity regimes.Using the tropospheric column FNR values from ozone monitoring instrument(OMI)satellite data as an indicator with the simulated threshold values,the spatial distributions of O_(3)formation regimes in China are determined.The O_(3)sensitivity regimes from eastern to central China are gradually from VOC-limited,transition to NO_(x)-limited spatially,and moving toward to transition or NO_(x)-limited regime from 2005 to 2019 temporally.展开更多
Soil biogenic NO emission is one of the most important sources of atmospheric nitrogen oxides(NOx) worldwide. However, the estimation of soil source, especially in arid areas presents large uncertainties because of th...Soil biogenic NO emission is one of the most important sources of atmospheric nitrogen oxides(NOx) worldwide. However, the estimation of soil source, especially in arid areas presents large uncertainties because of the substantial lack of measurements. In this study, we selected the Ruoqiang oases on the southeastern edge of the Taklimakan Desert, China as the study area and applied Ozone Monitoring Instrument(OMI) NO2 retrievals(DOMINO v2.0, 2005–2011) to investigate the spatial distribution and seasonal variations in tropospheric NO2 vertical column density(VCD). High NO2 VCDs were observed over the oases(farmlands and natural vegetation), with the highest value obtained during summer, and lowest during winter. Pulses were observed during spring. We conducted in-situ measurements in June 2011 in Milan oasis and employed ground-based multi-axis differential optical absorption spectroscopy(MAX-DOAS) instruments to validate satellite NO2 retrievals. The findings are as follows: 1) in the study area soil biogenic NO emission is the dominant source of tropospheric NO2; 2) oases(farmlands) are hotspots of tropospheric NO2, and a higher increase in tropospheric NO2 is found in oases from winter to summer; and 3) enhancement of soil biogenic NO emission due to soil managements is predictable. Given the rapid agricultural development in the southern Uygur Autonomous Region of Xinjiang, researches on soil biogenic NO emission and increase in tropospheric NOx should be given more importance.展开更多
文摘利用2005年1月至2017年12月搭载在美国环境监测Aura卫星上的臭氧监测仪(Ozone Monitoring Instrument,OMI)数据和NCEP气象资料,在夏季风环流指数定义方法的基础上,重新定义了南亚区域冬季风环流指数,并分别计算了南亚夏季风和冬季风环流指数.结合冬夏两季环流的强弱变化采用相关分析、合成分析和奇异值分解(Singular Value Decomposition,SVD)等方法,探讨了环流异常形势下臭氧的时空变化特征.结果表明:(1)南亚夏季纬向环流与经向环流的强度变化存在一致性,冬季经向环流与纬向环流的强度变化差异较大.(2)南亚臭氧柱总量的季节变化明显,且近13年来臭氧柱总量整体呈上升趋势.(3)夏季(冬季)风环流指数与对流层中低(中高)层和平流层中低层臭氧的相关性显著,但夏季平流层和对流层的相关趋势相反.(4)夏季风环流增强对应青藏高原-伊朗高原上空及南侧区域的上升运动增强,对臭氧的输送作用是造成对流层臭氧分布呈现差异的原因.(5)冬季风环流强弱期的垂直上升和下沉运动中心的移动,以及南北向、东西向气流交汇区的差异是造成臭氧分布不同的原因.
基金supported by National Key Research and Development Project(Nos.2018YFC0213504,2017YFC0213003,2016YFC0208905)
文摘Comprehensive air quality model with extensions(CAMx)-decoupled direct method(DDM)was used to simulate ozone-NO_(x)-VOCs sensitivity of for May-November in 2016-2018 in China.Based on the relationship between the simulated ozone(O_(3))sensitivity values and the ratio of formaldehyde(HCHO)to NO_(2)(FNR)and the ratio of production rate of hydrogen peroxide(H_(2)O_(2))to production rate of nitric acid(HNO_(3))(P_(H_(2)O_(2))/P_(HNO_(3))),the localized range of FNR and P_(H_(2)O_(2))/P_(HNO_(3))thresholds in different regions in China were obtained.The overall simulated FNR values are about 1.640-2.520,and P_(H_(2)O_(2))/P_(HNO_(3))values are about 0.540-0.830 for the transition regime.Model simulated O_(3)sensitivities or region specific FNR or P_(H_(2)O_(2))/P_(HNO_(3))thresholds should be applied to ensure the accurate local O3 sensitivity regimes.Using the tropospheric column FNR values from ozone monitoring instrument(OMI)satellite data as an indicator with the simulated threshold values,the spatial distributions of O_(3)formation regimes in China are determined.The O_(3)sensitivity regimes from eastern to central China are gradually from VOC-limited,transition to NO_(x)-limited spatially,and moving toward to transition or NO_(x)-limited regime from 2005 to 2019 temporally.
基金Under the auspices of German Research Foundation and Max Planck Society(No.MA 4798/1-1)National Natural Science Foundation of China(No.31070384)
文摘Soil biogenic NO emission is one of the most important sources of atmospheric nitrogen oxides(NOx) worldwide. However, the estimation of soil source, especially in arid areas presents large uncertainties because of the substantial lack of measurements. In this study, we selected the Ruoqiang oases on the southeastern edge of the Taklimakan Desert, China as the study area and applied Ozone Monitoring Instrument(OMI) NO2 retrievals(DOMINO v2.0, 2005–2011) to investigate the spatial distribution and seasonal variations in tropospheric NO2 vertical column density(VCD). High NO2 VCDs were observed over the oases(farmlands and natural vegetation), with the highest value obtained during summer, and lowest during winter. Pulses were observed during spring. We conducted in-situ measurements in June 2011 in Milan oasis and employed ground-based multi-axis differential optical absorption spectroscopy(MAX-DOAS) instruments to validate satellite NO2 retrievals. The findings are as follows: 1) in the study area soil biogenic NO emission is the dominant source of tropospheric NO2; 2) oases(farmlands) are hotspots of tropospheric NO2, and a higher increase in tropospheric NO2 is found in oases from winter to summer; and 3) enhancement of soil biogenic NO emission due to soil managements is predictable. Given the rapid agricultural development in the southern Uygur Autonomous Region of Xinjiang, researches on soil biogenic NO emission and increase in tropospheric NOx should be given more importance.
