利用气象与化学模块在线耦合的模式WRF-Chem V3.5(Weather Research and Forecasting Model coupled to Chemistry Version 3.5)对1323号台风Fitow进行了模拟,设计无人为排放源、含人为排放源和人为排放源增加的三组模拟试验,对比分析...利用气象与化学模块在线耦合的模式WRF-Chem V3.5(Weather Research and Forecasting Model coupled to Chemistry Version 3.5)对1323号台风Fitow进行了模拟,设计无人为排放源、含人为排放源和人为排放源增加的三组模拟试验,对比分析了人为气溶胶对台风的影响。结果表明:人为气溶胶对台风移动路径影响较小。人为气溶胶增加,台风强度减弱,台风主体总累积降水量减少,靠近陆地阶段台风主体降水率减少。气溶胶的增多可提供更多的凝结核,台风外围云水增加,更多的云水可上升至冻结层以上形成过冷水,促进冰相粒子的形成,释放的潜热增加,使外围对流增强,降水增加。台风外围对流的发展,使低层入流的暖湿空气更多的在外围上升,向台风中心的入流减弱,眼墙的发展减弱,降水减少,台风强度减弱。台风外围的对流发展弱于眼墙的对流,降水仍以眼墙区为主,使累积降水量和降水率整体上表现为减少。展开更多
Atmospheric chemistry models usually perform badly in forecasting wintertime air pollution because of their uncertainties. Generally, such uncertainties can be decreased effectively by techniques such as data assimila...Atmospheric chemistry models usually perform badly in forecasting wintertime air pollution because of their uncertainties. Generally, such uncertainties can be decreased effectively by techniques such as data assimilation（DA） and model output statistics（MOS）. However, the relative importance and combined effects of the two techniques have not been clarified. Here,a one-month air quality forecast with the Weather Research and Forecasting-Chemistry（WRF-Chem） model was carried out in a virtually operational setup focusing on Hebei Province, China. Meanwhile, three-dimensional variational（3 DVar） DA and MOS based on one-dimensional Kalman filtering were implemented separately and simultaneously to investigate their performance in improving the model forecast. Comparison with observations shows that the chemistry forecast with MOS outperforms that with 3 DVar DA, which could be seen in all the species tested over the whole 72 forecast hours. Combined use of both techniques does not guarantee a better forecast than MOS only, with the improvements and degradations being small and appearing rather randomly. Results indicate that the implementation of MOS is more suitable than 3 DVar DA in improving the operational forecasting ability of WRF-Chem.展开更多
Lima is the capital of the Republic of Peru. It is the most important city in the country and as other Latin America metropolises have multiple problems, including air pollution due to particulate material above air q...Lima is the capital of the Republic of Peru. It is the most important city in the country and as other Latin America metropolises have multiple problems, including air pollution due to particulate material above air quality standards, emitted by 1.6 million vehicles. The “on-line” coupled model of meteorology and chemistry of transport and meteorological/chemistry, WRF/Chem (Weather and Research Forecasting with Chemistry) has been used in the Lima Metropolitan Area, and validated against data observed at ground level with ten air quality stations of the National Service of Meteorology and Hydrology for the year 2016. The goal of this study was to estimate the concentration of PM2.5 particulate matter in the months of February and July of 2016. In both months, the model satisfactorily predicts temperature and relative humidity. The average observed PM2.5 concentrations in the month of July are higher than in February, probably because the relative humidity in July is greater than the relative humidity in February. In the months of February and July the standard observed deviations of the model have a factor of 2.4 and 3.7 respectively, indicating a greater dispersion in the data of the model. In the month of July, the model captures the characteristics of transport, shows characteristic peaks during peak hours, therefore, the model estimates transport behavior better in July than in February. The quality of the air is strongly influenced by the vehicular transport. The PM2.5 particulate material in February had an average bias that varied from [?13.2 to 4.4 μg/m3] and in July [?9.63 to 11.65 μg/m3] and a normalized average bias in February that varied from [?0.68 to 0.43] and in July of [?0.46 to 0.48].展开更多
To realistically simulate the impacts of marine isoprene and primary organic aerosols (POA) on atmospheric chemistry, a unified model framework with online emissions, comprehensive treatment of gas-phase chemistry, an...To realistically simulate the impacts of marine isoprene and primary organic aerosols (POA) on atmospheric chemistry, a unified model framework with online emissions, comprehensive treatment of gas-phase chemistry, and advanced aerosol microphysics is required. In this work, the global-through-urban WRF/Chem model (GU-WRF/Chem) implemented with the online emissions of marine isoprene and size-resolved marine POA is applied to examine such impacts. The net effect of these emissions was increased surface concentrations of isoprene and organic aerosols and decreased surfaced concentrations of hydroxyl radical and ozone over most marine regions. With the inclusion of these emissions, GU-WRF/Chem better predicted the surface concentrations of isoprene and organic aerosols and the aerosol number size distribution when compared to measurements in clean marine conditions.展开更多
有机化学是药学专业非常重要又较难学习的一门专业基础课,认识有机化合物的结构是学好这门课程的基础,单纯平面教学无法深入地将分子的实际空间结构加以充分展示。通过在有机化学实验课中开设球棍模型搭建及Chem Bio Office软件应用这...有机化学是药学专业非常重要又较难学习的一门专业基础课,认识有机化合物的结构是学好这门课程的基础,单纯平面教学无法深入地将分子的实际空间结构加以充分展示。通过在有机化学实验课中开设球棍模型搭建及Chem Bio Office软件应用这一内容,利用立体、形象的原子间的相对位置,可以促进学生迅速地理解、掌握化合物的立体结构,把握有机分子构成的基本方式,为后续的教学内容打下良好的基础。展开更多
Tropopause folds are one of the key mechanisms of stratosphere-troposphere exchange （STE） in extratropical regions, transporting ozone-rich stratospheric air into the middle and lower troposphere. Although there hav...Tropopause folds are one of the key mechanisms of stratosphere-troposphere exchange （STE） in extratropical regions, transporting ozone-rich stratospheric air into the middle and lower troposphere. Although there have been many studies of tropopause folds that have occurred over Europe and North America, a very limited amount of work has been carried out over northeastern Asia. Ozonesondes produced by the Institute of Atmospheric Physics were launched in Changchun （43.9°N, 125.2° E）, Northeast China, in June 2013, and observed an ozone-enriched layer with thickness of 3 km and an ozone peak of 180 ppbv at 6 km in the troposphere. The circulation field from the European Centre for Medium-Range Weather Forecasts Interim Reanalysis （ERA-Interim） dataset shows that this ozone peak was caused by a tropopause fold associated with a jet stream at the eastern flank of the East Asian trough. By analyzing the ozone data from the ozone monitoring instrument and Weather Research and Forecasting model with Chemistry （WRF-Chem） simulations, it was found that a high ozone concentration tongue originating from the lower stratosphere at high latitude （near central Siberia） intruded into the middle troposphere over Changchun between 5 and 8 km on 12 June 2013. The high-resolution WRF-Chem simulation was capable of describing events such as the tropopause fold that occurred on the cyclonic shear side of the jet stream. In addition, the TRAJ3D trajectory model was used to trace the origin of measured secondary ozone peaks in the middle troposphere back, for example, to stratospheric intrusion through the tropopause fold.展开更多
大气中CO2含量的增加速率已经超过了自然界所能吸收的速度,并逐步影响到全球气候变暖。利用模型模拟分析已经成为一个重要的工具用以深入对碳循环的理解。本文使用2008~2010年的生物模型SiB3(Simple Biosphere version 3)与优化后的CT20...大气中CO2含量的增加速率已经超过了自然界所能吸收的速度,并逐步影响到全球气候变暖。利用模型模拟分析已经成为一个重要的工具用以深入对碳循环的理解。本文使用2008~2010年的生物模型SiB3(Simple Biosphere version 3)与优化后的CT2016(Carbon Tracker 2016)陆地生态系统碳通量驱动GEOS-Chem大气化学传输模型模拟全球CO2浓度。通过分析模拟CO2浓度的空间分布与季节变化,加深对全球碳源汇分布特点的理解,探究陆地生态系统碳通量不确定性对模拟结果的影响,进而认识陆地生态系统碳通量反演精度提升的重要性。SiB3与优化后的CT2016陆地生态系统碳通量都具有明显的季节变化,但在欧洲地区碳源汇的表现相反,其全球总量与空间分布也存在极大的不确定性。模拟CO2浓度结果表明:在人为活动较少地区,陆地生态系统碳通量对近地面CO2浓度空间分布起主导作用,尤其在南半球和欧洲地区模拟浓度有明显差异,且两种模拟结果的季节差异依赖于陆地生态系统碳通量的季节变化。将模拟结果与9个观测站点资料进行对比,以期选用合适的陆地生态系统碳通量来提升GEOS-Chem模拟CO2浓度的精度。实验结果表明:两种模拟结果均能较好的模拟CO2浓度的季节变化及其峰谷值,但CT2016模拟的CO2浓度在多数站点处更接近观测资料,模拟准确性更高。展开更多
Many developed researches have confirmed the increasing of dust event and its dangerous impacts on the environment, health, economy, etc. in west and southwest ofIranduring the recent decade. This investigation aims t...Many developed researches have confirmed the increasing of dust event and its dangerous impacts on the environment, health, economy, etc. in west and southwest ofIranduring the recent decade. This investigation aims to have a comparison between the derived outputs from the dust simulation models and satellite images analysis over 22-26 June 2010, as this spell is considered a typical case of the dust event over the western/southwestern parts of Iran. We found that the obtained results from the HYSPLIT and WRF/CHEM models respectively on dust dispersion trajectories and aerosol concentration rate were reliable to be used in dust prediction systems over the region.展开更多
During the period from 9 to 11 November 2013,an explosive cyclone(EC)occurred over the Japan Sea-Okhotsk Sea.This EC initially formed around 18 UTC 9 November over the Japan Sea and developed over the Okhotsk Sea when...During the period from 9 to 11 November 2013,an explosive cyclone(EC)occurred over the Japan Sea-Okhotsk Sea.This EC initially formed around 18 UTC 9 November over the Japan Sea and developed over the Okhotsk Sea when moving northeastward.It had a minimum sea level pressure of 959.0 hPa,a significant deepening rate of central pressure of 2.9 Bergeron,and a maximum instantaneous wind speed of 42.7 m s−1.This paper aims to investigate the conditions that contributed to the rapid development of this low-pressure system through analyses of both observations and the Weather Research Forecasting(WRF)modeling results.The evolutionary processes of this EC were examined by using Final Analyses(FNL)data,Multi-Functional Transport Satellites-1R(MTSAT-1R)data,upper observation data and surface observation data.WRF-3.5 modeling results were also used to examine the development mechanism of this EC.It is shown that the interaction between upper-level and low-level potential vorticity seemed to be very essential to the rapid development of this EC.展开更多
文摘利用气象与化学模块在线耦合的模式WRF-Chem V3.5(Weather Research and Forecasting Model coupled to Chemistry Version 3.5)对1323号台风Fitow进行了模拟,设计无人为排放源、含人为排放源和人为排放源增加的三组模拟试验,对比分析了人为气溶胶对台风的影响。结果表明:人为气溶胶对台风移动路径影响较小。人为气溶胶增加,台风强度减弱,台风主体总累积降水量减少,靠近陆地阶段台风主体降水率减少。气溶胶的增多可提供更多的凝结核,台风外围云水增加,更多的云水可上升至冻结层以上形成过冷水,促进冰相粒子的形成,释放的潜热增加,使外围对流增强,降水增加。台风外围对流的发展,使低层入流的暖湿空气更多的在外围上升,向台风中心的入流减弱,眼墙的发展减弱,降水减少,台风强度减弱。台风外围的对流发展弱于眼墙的对流,降水仍以眼墙区为主,使累积降水量和降水率整体上表现为减少。
基金supported by the State Key Research and Development Program (Grant Nos. 2017YFC0209803, 2016YFC0208504, 2016YFC0203303 and 2017YFC0210106)the National Natural Science Foundation of China (Grant Nos. 91544230, 41575145, 41621005 and 41275128)
文摘Atmospheric chemistry models usually perform badly in forecasting wintertime air pollution because of their uncertainties. Generally, such uncertainties can be decreased effectively by techniques such as data assimilation（DA） and model output statistics（MOS）. However, the relative importance and combined effects of the two techniques have not been clarified. Here,a one-month air quality forecast with the Weather Research and Forecasting-Chemistry（WRF-Chem） model was carried out in a virtually operational setup focusing on Hebei Province, China. Meanwhile, three-dimensional variational（3 DVar） DA and MOS based on one-dimensional Kalman filtering were implemented separately and simultaneously to investigate their performance in improving the model forecast. Comparison with observations shows that the chemistry forecast with MOS outperforms that with 3 DVar DA, which could be seen in all the species tested over the whole 72 forecast hours. Combined use of both techniques does not guarantee a better forecast than MOS only, with the improvements and degradations being small and appearing rather randomly. Results indicate that the implementation of MOS is more suitable than 3 DVar DA in improving the operational forecasting ability of WRF-Chem.
文摘Lima is the capital of the Republic of Peru. It is the most important city in the country and as other Latin America metropolises have multiple problems, including air pollution due to particulate material above air quality standards, emitted by 1.6 million vehicles. The “on-line” coupled model of meteorology and chemistry of transport and meteorological/chemistry, WRF/Chem (Weather and Research Forecasting with Chemistry) has been used in the Lima Metropolitan Area, and validated against data observed at ground level with ten air quality stations of the National Service of Meteorology and Hydrology for the year 2016. The goal of this study was to estimate the concentration of PM2.5 particulate matter in the months of February and July of 2016. In both months, the model satisfactorily predicts temperature and relative humidity. The average observed PM2.5 concentrations in the month of July are higher than in February, probably because the relative humidity in July is greater than the relative humidity in February. In the months of February and July the standard observed deviations of the model have a factor of 2.4 and 3.7 respectively, indicating a greater dispersion in the data of the model. In the month of July, the model captures the characteristics of transport, shows characteristic peaks during peak hours, therefore, the model estimates transport behavior better in July than in February. The quality of the air is strongly influenced by the vehicular transport. The PM2.5 particulate material in February had an average bias that varied from [?13.2 to 4.4 μg/m3] and in July [?9.63 to 11.65 μg/m3] and a normalized average bias in February that varied from [?0.68 to 0.43] and in July of [?0.46 to 0.48].
文摘To realistically simulate the impacts of marine isoprene and primary organic aerosols (POA) on atmospheric chemistry, a unified model framework with online emissions, comprehensive treatment of gas-phase chemistry, and advanced aerosol microphysics is required. In this work, the global-through-urban WRF/Chem model (GU-WRF/Chem) implemented with the online emissions of marine isoprene and size-resolved marine POA is applied to examine such impacts. The net effect of these emissions was increased surface concentrations of isoprene and organic aerosols and decreased surfaced concentrations of hydroxyl radical and ozone over most marine regions. With the inclusion of these emissions, GU-WRF/Chem better predicted the surface concentrations of isoprene and organic aerosols and the aerosol number size distribution when compared to measurements in clean marine conditions.
文摘有机化学是药学专业非常重要又较难学习的一门专业基础课,认识有机化合物的结构是学好这门课程的基础,单纯平面教学无法深入地将分子的实际空间结构加以充分展示。通过在有机化学实验课中开设球棍模型搭建及Chem Bio Office软件应用这一内容,利用立体、形象的原子间的相对位置,可以促进学生迅速地理解、掌握化合物的立体结构,把握有机分子构成的基本方式,为后续的教学内容打下良好的基础。
基金supported by the National Basic Research Program of China under Grant No.2010CB428602the National Natural Science Foundation of China (Grant No. 41175040)
文摘Tropopause folds are one of the key mechanisms of stratosphere-troposphere exchange （STE） in extratropical regions, transporting ozone-rich stratospheric air into the middle and lower troposphere. Although there have been many studies of tropopause folds that have occurred over Europe and North America, a very limited amount of work has been carried out over northeastern Asia. Ozonesondes produced by the Institute of Atmospheric Physics were launched in Changchun （43.9°N, 125.2° E）, Northeast China, in June 2013, and observed an ozone-enriched layer with thickness of 3 km and an ozone peak of 180 ppbv at 6 km in the troposphere. The circulation field from the European Centre for Medium-Range Weather Forecasts Interim Reanalysis （ERA-Interim） dataset shows that this ozone peak was caused by a tropopause fold associated with a jet stream at the eastern flank of the East Asian trough. By analyzing the ozone data from the ozone monitoring instrument and Weather Research and Forecasting model with Chemistry （WRF-Chem） simulations, it was found that a high ozone concentration tongue originating from the lower stratosphere at high latitude （near central Siberia） intruded into the middle troposphere over Changchun between 5 and 8 km on 12 June 2013. The high-resolution WRF-Chem simulation was capable of describing events such as the tropopause fold that occurred on the cyclonic shear side of the jet stream. In addition, the TRAJ3D trajectory model was used to trace the origin of measured secondary ozone peaks in the middle troposphere back, for example, to stratospheric intrusion through the tropopause fold.
文摘Many developed researches have confirmed the increasing of dust event and its dangerous impacts on the environment, health, economy, etc. in west and southwest ofIranduring the recent decade. This investigation aims to have a comparison between the derived outputs from the dust simulation models and satellite images analysis over 22-26 June 2010, as this spell is considered a typical case of the dust event over the western/southwestern parts of Iran. We found that the obtained results from the HYSPLIT and WRF/CHEM models respectively on dust dispersion trajectories and aerosol concentration rate were reliable to be used in dust prediction systems over the region.
基金the National Natural Science Foundation of China(NSFC)for financial support(Nos.41775042 and 41275049)。
文摘During the period from 9 to 11 November 2013,an explosive cyclone(EC)occurred over the Japan Sea-Okhotsk Sea.This EC initially formed around 18 UTC 9 November over the Japan Sea and developed over the Okhotsk Sea when moving northeastward.It had a minimum sea level pressure of 959.0 hPa,a significant deepening rate of central pressure of 2.9 Bergeron,and a maximum instantaneous wind speed of 42.7 m s−1.This paper aims to investigate the conditions that contributed to the rapid development of this low-pressure system through analyses of both observations and the Weather Research Forecasting(WRF)modeling results.The evolutionary processes of this EC were examined by using Final Analyses(FNL)data,Multi-Functional Transport Satellites-1R(MTSAT-1R)data,upper observation data and surface observation data.WRF-3.5 modeling results were also used to examine the development mechanism of this EC.It is shown that the interaction between upper-level and low-level potential vorticity seemed to be very essential to the rapid development of this EC.
