Low particulate nitrate in the residual layer in autumn over the North China Plain

2021 ◽  
pp. 146845
Author(s):  
Guiqian Tang ◽  
Yinghong Wang ◽  
Yusi Liu ◽  
Shuang Wu ◽  
Xiaojuan Huang ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Residual Layer ◽  
The North ◽  
The North China Plain

An evaluation of the interaction of morning residual layer ozone and mixing layer ozone in rural areas of the North China Plain

2020 ◽  
Vol 236 ◽  
pp. 104788 ◽  
Author(s):  
Xiaowan Zhu ◽  
Zhiqiang Ma ◽  
Yulu Qiu ◽  
Hui Liu ◽  
Quan Liu ◽  
...  
Keyword(s):  
Rural Areas ◽  
North China Plain ◽  
North China ◽  
Mixing Layer ◽  
Residual Layer ◽  
The North ◽  
The North China Plain

scholarly journals Fast heterogeneous N<sub>2</sub>O<sub>5</sub> uptake and ClNO<sub>2</sub> production in power plant and industrial plumes observed in the nocturnal residual layer over the North China Plain

2017 ◽  
Vol 17 (20) ◽  
pp. 12361-12378 ◽  
Author(s):  
Zhe Wang ◽  
Weihao Wang ◽  
Yee Jun Tham ◽  
Qinyi Li ◽  
Hao Wang ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Northern China ◽  
Residual Layer ◽  
Tropospheric Chemistry ◽  
Aerosol Formation ◽  
The North ◽  
The North China Plain ◽  
Haze Pollution ◽  
Key Species

Abstract. Dinitrogen pentoxide (N2O5) and nitryl chloride (ClNO2) are key species in nocturnal tropospheric chemistry and have significant effects on particulate nitrate formation and the following day's photochemistry through chlorine radical production and NOx recycling upon photolysis of ClNO2. To better understand the roles of N2O5 and ClNO2 in the high-aerosol-loading environment of northern China, an intensive field study was carried out at a high-altitude site (Mt. Tai, 1465 m a.s.l.) in the North China Plain (NCP) during the summer of 2014. Elevated ClNO2 plumes were frequently observed in the nocturnal residual layer with a maximum mixing ratio of 2.1 ppbv (1 min), whilst N2O5 was typically present at very low levels (< 30 pptv), indicating fast heterogeneous N2O5 hydrolysis. Combined analyses of chemical characteristics and backward trajectories indicated that the ClNO2-laden air was caused by the transport of NOx-rich plumes from the coal-fired industry and power plants in the NCP. The heterogeneous N2O5 uptake coefficient (γ) and ClNO2 yield (ϕ) were estimated from steady-state analysis and observed growth rate of ClNO2. The derived γ and ϕ exhibited high variability, with means of 0.061 ± 0.025 and 0.28 ± 0.24, respectively. These values are higher than those derived from previous laboratory and field studies in other regions and cannot be well characterized by model parameterizations. Fast heterogeneous N2O5 reactions dominated the nocturnal NOx loss in the residual layer over this region and contributed to substantial nitrate formation of up to 17 µg m−3. The estimated nocturnal nitrate formation rates ranged from 0.2 to 4.8 µg m−3 h−1 in various plumes, with a mean of 2.2  ± 1.4 µg m−3 h−1. The results demonstrate the significance of heterogeneous N2O5 reactivity and chlorine activation in the NCP, and their unique and universal roles in fine aerosol formation and NOx transformation, and thus their potential impacts on regional haze pollution in northern China.

scholarly journals Lower tropospheric distributions of O<sub>3</sub> and aerosol over Raoyang, a rural site in the North China Plain

2016 ◽  
Author(s):  
Rui Wang ◽  
Xiaobin Xu ◽  
Shihui Jia ◽  
Ruisheng Ma ◽  
Liang Ran ◽  
...  
Keyword(s):  
Mixed Layer ◽  
North China Plain ◽  
North China ◽  
Number Concentration ◽  
Residual Layer ◽  
Rural Site ◽  
Vertical Profiles ◽  
The North ◽  
The North China Plain ◽  
Aerosol Number Concentration

Abstract. The North China Plain (NCP) has become one of the most polluted regions in China, with the rapid increasing economic growth in the past decades. High concentrations of ambient O3 and aerosol have been observed at urban as well as rural sites in the NCP. Most of the in situ observations of air pollutants have been conducted near the ground so that current knowledge about the vertical distributions of tropospheric O3 and aerosol over the NCP region is still quite limited. In this study, vertical profiles of O3 and size-resolved aerosol concentrations below 2.5 km were measured in summer 2014 over a rural site in the NCP using an unmanned aerial vehicle (UAV) equipped with miniature analyzers. In addition, vertical profiles of aerosol scattering property in the lower troposphere and vertical profiles of O3 below 1 km were also observed at the site using a LIDAR and tethered balloon, respectively. The depths of the mixed layer and residual layer were determined using two methods. Average O3 and size-resolved aerosol number concentration in both the mixed and residual layer were obtained from the data observed in seven UAV flights. The results show that during most of the flights the O3 levels above the top of mixed layer were higher than those below. Such positive gradient in vertical distribution of O3 makes the residual layer an important source of O3 in the mixed layer, particularly during morning when the top of mixed layer is rapidly elevated. In contrast to O3, aerosol number concentration was normally higher in the mixed layer than in the residual layer, particularly in early morning. Aerosol particles were overwhelmingly distributed in the size range

scholarly journals Fast heterogeneous N<sub>2</sub>O<sub>5</sub> uptake and ClNO<sub>2</sub> production in power plant plumes observed in the nocturnal residual layer over the North China Plain

2017 ◽  
Author(s):  
Zhe Wang ◽  
Weihao Wang ◽  
Yee Jun Tham ◽  
Qinyi Li ◽  
Hao Wang ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Northern China ◽  
Residual Layer ◽  
Tropospheric Chemistry ◽  
Aerosol Formation ◽  
The North ◽  
The North China Plain ◽  
Haze Pollution ◽  
Key Species

Abstract. Dinitrogen pentoxide (N2O5) and nitryl chloride (ClNO2) are key species in nocturnal tropospheric chemistry, and have significant effects on particulate nitrate formation and the following day’s photochemistry. To better understand the roles of N2O5 and ClNO2 in the high aerosol loading environment of northern China, an intensive field study was carried out at a high-altitude site (Mt. Tai, 1465 m a.s.l.) in the North China Plain (NCP) during the summer of 2014. Elevated ClNO2 plumes were frequently observed in the nocturnal residual layer with a maximum mixing ratio of 2.1 ppbv (1-min), whilst N2O5 was typically present at very low levels (<30 pptv), indicating fast heterogeneous N2O5 hydrolysis. Combined analyses of chemical characteristics and backward trajectories indicated that the ClNO2-laden air was caused by the transport of NOx-rich plumes from the coal-fired power plants in the NCP. The heterogeneous N2O5 uptake coefficient (γ) and ClNO2 yield (ϕ) during the campaign exhibited high variability, with means of 0.061 ± 0.025 and 0.27 ± 0.24, respectively. These derived values are higher than those derived from previous laboratory and field studies in other regions, and cannot be well characterized by model parameterizations. Fast heterogeneous N2O5 reactions dominated the nocturnal NOx loss in the residual layer over this region, and contributed to substantial nitrate formation of up to 17 μg m−3. The determined nocturnal nitrate formation rates ranged from 0.2 to 4.8 μg m−3 hr−1 in various plumes, with a mean of 2.2 ± 1.4 μg m−3 h−1. The results demonstrate the significance of heterogeneous N2O5 reactivity and chlorine activation in the NCP, and their unique and universal roles in fine aerosol formation and NOx transformation, and thus potential impacts on regional haze pollution in northern China.

ROx Budgets and O3 Formation during Summertime at Xianghe Suburban Site in the North China Plain

2021 ◽  
Author(s):  
Min Xue ◽  
Jianzhong Ma ◽  
Guiqian Tang ◽  
Shengrui Tong ◽  
Bo Hu ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
The North ◽  
The North China Plain ◽  
Suburban Site

scholarly journals Improving the Resolution and Accuracy of Groundwater Level Anomalies Using the Machine Learning-Based Fusion Model in the North China Plain

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 46
Author(s):  
Gangqiang Zhang ◽  
Wei Zheng ◽  
Wenjie Yin ◽  
Weiwei Lei
Keyword(s):  
Machine Learning ◽  
Data Fusion ◽  
Groundwater Level ◽  
North China Plain ◽  
North China ◽  
Gradient Boosting ◽  
Fusion Model ◽  
The North ◽  
The North China Plain ◽  
Prediction Module

The launch of GRACE satellites has provided a new avenue for studying the terrestrial water storage anomalies (TWSA) with unprecedented accuracy. However, the coarse spatial resolution greatly limits its application in hydrology researches on local scales. To overcome this limitation, this study develops a machine learning-based fusion model to obtain high-resolution (0.25°) groundwater level anomalies (GWLA) by integrating GRACE observations in the North China Plain. Specifically, the fusion model consists of three modules, namely the downscaling module, the data fusion module, and the prediction module, respectively. In terms of the downscaling module, the GRACE-Noah model outperforms traditional data-driven models (multiple linear regression and gradient boosting decision tree (GBDT)) with the correlation coefficient (CC) values from 0.24 to 0.78. With respect to the data fusion module, the groundwater level from 12 monitoring wells is incorporated with climate variables (precipitation, runoff, and evapotranspiration) using the GBDT algorithm, achieving satisfactory performance (mean values: CC: 0.97, RMSE: 1.10 m, and MAE: 0.87 m). By merging the downscaled TWSA and fused groundwater level based on the GBDT algorithm, the prediction module can predict the water level in specified pixels. The predicted groundwater level is validated against 6 in-situ groundwater level data sets in the study area. Compare to the downscaling module, there is a significant improvement in terms of CC metrics, on average, from 0.43 to 0.71. This study provides a feasible and accurate fusion model for downscaling GRACE observations and predicting groundwater level with improved accuracy.

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