scholarly journals The Strengthening Relationship between Eurasian Snow Cover and December Haze Days in Central North China after the Mid-1990s

2017 ◽  
Author(s):  
Zhicong Yin ◽  
Huijun Wang
Keyword(s):  
Soil Moisture ◽  
Snow Cover ◽  
North China ◽  
Surface Wind ◽  
Surface Radiation ◽  
Radiative Cooling ◽  
Atmospheric Circulations ◽  
Haze Pollution ◽  
The Relationship ◽  
Haze Days

Abstract. The haze pollution in December has become increasingly serious over recent decades and imposes damage on society, ecosystems, and human health. In addition to anthropogenic emissions, climate change and variability were conducive to haze in China. In this study, the relationship between the snow cover over East Europe and West Siberia (SCES) and the number of haze days in December in central North China was analyzed. This relationship significantly strengthened after the mid-1990s, which is attributed to the effective connections between the SCES and the Eurasian atmospheric circulations. During 1998–2016, the SCES significantly influenced the soil moisture and land surface radiation, and then, the combined underlying drivers of enhanced soil moisture and radiative cooling moved the East Asia jet stream northward and induced anomalous, anti-cyclonic circulation over central North China. Modulated by such atmospheric circulations, the local lower boundary layer, the decreased surface wind and the more humid air were conducive to the worsening dispersion conditions and frequent haze occurrences. In contrast, from 1979 to 1997, the linkage between the SCES and soil moisture was negligible. Furthermore, the correlated radiative cooling was distributed narrowly and far from the key area of snow cover. The associated atmospheric circulations with the SCES were not significantly linked with the ventilation conditions over central North China. Consequently, the relationship between the SCES and the number of hazy days in central North China was insignificant before the mid-1990s but has strengthened and has become significant since then.

scholarly journals The strengthening relationship between Eurasian snow cover and December haze days in central North China after the mid-1990s

2018 ◽  
Vol 18 (7) ◽  
pp. 4753-4763 ◽  
Author(s):  
Zhicong Yin ◽  
Huijun Wang
Keyword(s):  
Soil Moisture ◽  
Snow Cover ◽  
North China ◽  
Surface Wind ◽  
Surface Radiation ◽  
Radiative Cooling ◽  
Atmospheric Circulations ◽  
Haze Pollution ◽  
The Relationship ◽  
Haze Days

Abstract. The haze pollution in December has become increasingly serious over recent decades and imposes damage on society, ecosystems, and human health. In addition to anthropogenic emissions, climate change and variability were conducive to haze in China. In this study, the relationship between the snow cover over eastern Europe and western Siberia (SCES) and the number of haze days in December in central North China was analyzed. This relationship significantly strengthened after the mid-1990s, which is attributed to the effective connections between the SCES and the Eurasian atmospheric circulations. During 1998–2016, the SCES significantly influenced the soil moisture and land surface radiation, and then the combined underlying drivers of enhanced soil moisture and radiative cooling moved the the East Asia jet stream northward and induced anomalous, anti-cyclonic circulation over central North China. Modulated by such atmospheric circulations, the local lower boundary layer, the decreased surface wind, and the more humid air were conducive to the worsening dispersion conditions and frequent haze occurrences. In contrast, from 1979 to 1997, the linkage between the SCES and soil moisture was negligible. Furthermore, the correlated radiative cooling was distributed narrowly and far from the key area of snow cover. The associated atmospheric circulations with the SCES were not significantly linked with the ventilation conditions over central North China. Consequently, the relationship between the SCES and the number of hazy days in central North China was insignificant before the mid-1990s but has strengthened and has become significant since then.

scholarly journals Effects of Winter Snow Cover on Spring Soil Moisture Based on Remote Sensing Data Product over Farmland in Northeast China

2020 ◽  
Vol 12 (17) ◽  
pp. 2716
Author(s):  
Shuang Liang ◽  
Xiaofeng Li ◽  
Xingming Zheng ◽  
Tao Jiang ◽  
Xiaojie Li ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Soil Moisture ◽  
Linear Regression ◽  
Snow Cover ◽  
Snow Depth ◽  
Northeast China ◽  
Regression Models ◽  
Linear Regression Models ◽  
Winter Snow ◽  
The Relationship

Spring soil moisture (SM) is of great importance for monitoring agricultural drought and waterlogging in farmland areas. While winter snow cover has an important impact on spring SM, relatively little research has examined the correlation between winter snow cover and spring SM in great detail. To understand the effects of snow cover on SM over farmland, the relationship between winter snow cover parameters (maximum snow depth (MSD) and average snow depth (ASD)) and spring SM in Northeast China was examined based on 30 year passive microwave snow depth (SD) and SM remote-sensing products. Linear regression models based on winter snow cover were established to predict spring SM. Moreover, 4 year SD and SM data were applied to validate the performance of the linear regression models. Additionally, the effects of meteorological factors on spring SM also were analyzed using multiparameter linear regression models. Finally, as a specific application, the best-performing model was used to predict the probability of spring drought and waterlogging in farmland in Northeast China. Our results illustrated the positive effects of winter snow cover on spring SM. The average correlation coefficient (R) of winter snow cover and spring SM was above 0.5 (significant at a 95% confidence level) over farmland. The performance of the relationship between snow cover and SM in April was better than that in May. Compared to the multiparameter linear regression models in terms of fitting coefficient, MSD can be used as an important snow parameter to predict spring drought and waterlogging probability in April. Specifically, if the relative SM threshold is 50% when spring drought occurs in April, the prediction probability of the linear regression model concerning snow cover and spring SM can reach 74%. This study improved our understanding of the effects of winter snow cover on spring SM and will be beneficial for further studies on the prediction of spring drought.

scholarly journals Understanding the Recent Trend of Haze Pollution in Eastern China: Roles of Climate Change

2016 ◽  
Author(s):  
H. J. Wang ◽  
H. P. Chen
Keyword(s):  
Energy Consumption ◽  
North China ◽  
Eastern China ◽  
Arctic Sea Ice ◽  
Total Energy Consumption ◽  
Sea Ice Extent ◽  
Haze Pollution ◽  
Arctic Sea ◽  
Haze Days ◽  
Arctic Sea Ice Extent

Abstract. In this paper, the variation and trend of haze pollution in eastern China for winter of 1960–2012 were analyzed. With the overall increasing number of winter haze days in the period, the five decades were divided into three sub-periods based on the changes of winter haze days (WHD) in central North China (30° N–40° N) and eastern South China (south of 30° N) for east of 109° E mainland China. Results show that WHD kept gradual increasing during 1960–1979, overall stable during 1980–1999, and fast increasing during 2000–2012. The author identified the major climate forcing factors besides total energy consumption. Among all the possible climate factors, variability of the autumn Arctic sea ice extent, local precipitation and surface wind during winter is most influential to the haze pollution change. The joint effect of fast increase of total energy consumption, rapid decline of Arctic sea ice extent and reduced precipitation and surface winds intensified the haze pollution in central North China after 2000. There is similar conclusion for haze pollution in eastern South China after 2000, with the precipitation effect being smaller and spatially inconsistent.

scholarly journals Role of Atmospheric Circulations on Haze Pollution in December 2016

2017 ◽  
Author(s):  
Zhicong Yin ◽  
Huijun Wang
Keyword(s):  
Surface Wind ◽  
Weather Conditions ◽  
Gulf Of Alaska ◽  
Surface Wind Speed ◽  
Control Measures ◽  
Anthropogenic Emissions ◽  
Small Surface ◽  
Atmospheric Circulations ◽  
Haze Pollution

Abstract. In the east of China, recent haze pollution has been severe and damaging. In addition to anthropogenic emissions, atmospheric circulations and local meteorological conditions were conductive factors. The number of December haze days over North China and the Huanghuai area has increased sharply since 2010 and was greatest in 2016. During 2016, the most aggressive control measures for anthropogenic emissions were executed from 16–21 December, but the most severe haze pollution still occurred, covering approximately 25 % of the land area of China and lasting for 6 days. The atmospheric circulations must play critical roles. The associated atmospheric circulations that were verified by climatic correlation analysis were a weaker East Asia jet stream in the upper troposphere, a positive phase of the East Atlantic/West Russia pattern in the middle troposphere and conductive local weather conditions (lower PBL, small surface wind speed, and abundant moisture) near the surface. The influence of sea surface temperature near the Gulf of Alaska and the subtropical eastern Pacific, snow cover in western Siberia and associated physical processes on haze pollution are also discussed.

scholarly journals Melting of Perennial Sea Ice in the Beaufort Sea Enhanced Its Impacts on Early-Winter Haze Pollution in North China after the Mid-1990s

2020 ◽  
Vol 33 (12) ◽  
pp. 5061-5080 ◽  
Author(s):  
Yuyan Li ◽  
Zhicong Yin
Keyword(s):  
Sea Ice ◽  
North China ◽  
Beaufort Sea ◽  
Gulf Of Alaska ◽  
Ice Cover ◽  
Sea Surface ◽  
Haze Pollution ◽  
Sea Surface Temperature Anomalies ◽  
Haze Days ◽  
Perennial Ice

AbstractIn recent years, haze pollution has become the most concerning environmental issue in China due to its tremendous negative effects. In this study, we focus on the enhanced responses of December–January haze days in North China to September–October sea ice in the Beaufort Sea during 1998–2015. Via both observation and numerical approaches, compared with an earlier period (1980–97), the sea ice concentration in the Beaufort Sea presented large variability during 1998–2015. During 1980–97, the Beaufort Sea was mainly covered by perennial ice, and the ablation and freezing of sea ice mainly occurred at the south edge of the Beaufort Sea. Thus, heavy sea ice in autumn induced negative sea surface temperature anomalies across the Gulf of Alaska in November. However, the colder sea surface in the Gulf of Alaska only induced a weak influence on the haze-associated atmospheric circulations. In contrast, during 1998–2015, a drastic change in sea ice existed near the center of the Arctic Ocean, due to the massive melting of multiyear sea ice in the western Beaufort Sea. The perennial ice cover in the western Beaufort Sea was replaced by seasonal ice. The broader sea ice cover resulted in positive sea surface temperature anomalies in the following November. Then, suitable atmospheric backgrounds were induced for haze pollution in December and January. Simultaneously, the response of the number of haze days over North China to sea ice cover increased. These findings were verified by the CESM-LE simulations and aided in deepening the understanding of the cause of haze pollution.

scholarly journals Seasonal prediction of winter haze days in the north central North China Plain

2016 ◽  
Vol 16 (23) ◽  
pp. 14843-14852 ◽  
Author(s):  
Zhicong Yin ◽  
Huijun Wang
Keyword(s):  
Prediction Model ◽  
North China Plain ◽  
North China ◽  
Additive Model ◽  
Continuous Increase ◽  
North Central ◽  
The North ◽  
Predictive Skill ◽  
Haze Pollution ◽  
Haze Days

Abstract. Recently, the winter (December–February) haze pollution over the north central North China Plain (NCP) has become severe. By treating the year-to-year increment as the predictand, two new statistical schemes were established using the multiple linear regression (MLR) and the generalized additive model (GAM). By analyzing the associated increment of atmospheric circulation, seven leading predictors were selected to predict the upcoming winter haze days over the NCP (WHDNCP). After cross validation, the root mean square error and explained variance of the MLR (GAM) prediction model was 3.39 (3.38) and 53 % (54 %), respectively. For the final predicted WHDNCP, both of these models could capture the interannual and interdecadal trends and the extremums successfully. Independent prediction tests for 2014 and 2015 also confirmed the good predictive skill of the new schemes. The predicted bias of the MLR (GAM) prediction model in 2014 and 2015 was 0.09 (−0.07) and −3.33 (−1.01), respectively. Compared to the MLR model, the GAM model had a higher predictive skill in reproducing the rapid and continuous increase of WHDNCP after 2010.

scholarly journals Haze pollution in winter and summer in Zibo, a heavily industrialized city neighboring the Jin-Jin-Ji area of China: source, formation, and implications

2018 ◽  
Author(s):  
Hui Li ◽  
Fengkui Duan ◽  
Yongliang Ma ◽  
Kebin He ◽  
Lidan Zhu ◽  
...  
Keyword(s):  
North China ◽  
Control Policy ◽  
Photochemical Activity ◽  
Heterogeneous Reactions ◽  
Air Pollution Control ◽  
The North ◽  
Haze Pollution ◽  
High Concentrations ◽  
Pollution Control Policy ◽  
Haze Days

Abstract. Continuous field observations of haze pollution were conducted in winter and summer during 2015 in Zibo, a highly industrialized city in the North China Plain that is adjacent to the Jing-Jin-Ji area. PM2.5 concentration averaged 146.7 ± 85.8 and 82.2 ± 44.3 μg m−3 in winter and summer, respectively. The chemical component contributions to PM2.5 showed obvious seasonal variation. Organics were high in winter, but secondary inorganic aerosols (SIA) were high in summer. From non-haze to haze days, the concentration of SIA increased, implying an important role of secondary processes in the evolution process of the pollution. The diurnal behavior of several pollutants during haze days appeared to fluctuate more, but during non-haze days, it was much more stable, suggesting that complex mechanisms are involved. Specifically, gaseous precursors, mixed layer height (MLH), photochemical activity, and relative humidity (RH) also played important roles in the diurnal variation of the pollutants. Normally, larger gaseous precursor concentrations, photochemical activity, and RH, and lower MLH favored high concentrations. In winter, the formation of sulfate was mainly influenced by RH, indicating the importance of heterogeneous reactions in its formation. In contrast, in summer, photochemistry and SO2 concentration had the largest impact on the sulfate level. We found that Zibo was an ammonia-rich city, especially in winter, meaning that the formation of nitrate was through homogeneous reactions between HNO3 and NH3 in the gas phase, followed by partitioning into the particle phase. The RH, NO2, and Excess NH4+ were the main influencing factors for nitrate in winter, whereas Excess NH4+, RH, and temperature were the key factors in summer. The secondary organic carbon (SOC) level depended on the MLH and photochemistry. In winter, the effect of the MLH was stronger than that of photochemistry, but a reversed situation occurred in summer because of the intensive photochemistry. Our work suggested that the inter-transport between Zibo, one of the most polluted cities in north China, and its adjacent areas should be taken into account when formulating air pollution control policy.

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