scholarly journals The Effects of El Niño-South Oscillation on the Winter Haze Pollution of China

2017 ◽  
Author(s):  
Shuyun Zhao ◽  
Hua Zhang ◽  
Bing Xie
Keyword(s):  
East Asia ◽  
El Niño ◽  
El Nino ◽  
Southern China ◽  
Eastern China ◽  
La Niña ◽  
Anthropogenic Aerosols ◽  
La Nina ◽  
Haze Pollution ◽  
Haze Days

Abstract. It is reported in previous studies that El Niño-South Oscillation (ENSO) influences not only the summer monsoon, but also the winter monsoon over East Asia. This contains some clues that ENSO may affect the winter haze pollution of China, which has become a serious problem in recent decades, through influencing the winter climate of East Asia. In this work, we explore the effects of ENSO on the winter (from December to February) haze pollution of China statistically and numerically. Statistical results reveal that the haze days of southern China tend to be less (more) than normal in El Niño (La Niña) winter; whereas the winter haze days of northern and eastern China have no significant relationship with ENSO. Results from numerical simulations show that under the emission level of aerosols for the year 2010, the winter-average atmospheric contents of anthropogenic aerosols over southern China are generally more (less) than normal in El Niño (La Niña) winter. It is because that the transports of aerosols from South and Southeast Asia to southern China are enhanced (weakened), which mask the better (worse) scavenging conditions for aerosols in El Niño (La Niña) winter. The probability density function (PDF) of the simulated daily surface concentrations of aerosols over southern China indicates that the region tends to have less clean and moderate (heavy) haze days, but more heavy (moderate) haze days in El Niño (La Niña) winter.

scholarly journals The effects of El Niño–Southern Oscillation on the winter haze pollution of China

2018 ◽  
Vol 18 (3) ◽  
pp. 1863-1877 ◽  
Author(s):  
Shuyun Zhao ◽  
Hua Zhang ◽  
Bing Xie
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Southern China ◽  
Eastern China ◽  
La Niña ◽  
Anthropogenic Aerosol ◽  
La Nina ◽  
Haze Pollution ◽  
Haze Days

Abstract. It has been reported in previous studies that El Niño–Southern Oscillation (ENSO) influenced not only the summer monsoon, but also the winter monsoon over East Asia. This contains some clues that ENSO may affect the winter haze pollution of China, which has become a serious problem in recent decades, through influencing the winter climate of East Asia. In this work, we explored the effects of ENSO on the winter (from December to February) haze pollution of China statistically and numerically. Statistical results revealed that the haze days of southern China tended to be fewer (more) than normal in El Niño (La Niña) winter, whereas the relationships between the winter haze days of northern and eastern China and ENSO were not significant. Results from numerical simulations also showed that ENSO influenced the winter atmospheric anthropogenic aerosol content over southern China more obviously than it did over northern and eastern China. Under the emission level of aerosols for the year 2010, winter atmospheric anthropogenic aerosol content over southern China was generally greater (less) than normal in El Niño (La Niña) winter. This was because the transport of aerosols from South and Southeast Asia to southern China was enhanced (weakened), which masked the better (worse) scavenging conditions for aerosols in El Niño (La Niña) winter. The frequency distribution of the simulated daily surface concentrations of aerosols over southern China indicated that the region tended to have fewer clean and moderate (heavy) haze days, but more heavy (moderate) haze days in El Niño (La Niña) winter.

Spatio-temporal variability of lightning and convective activity over South/South-East Asia with an emphasis during El Niño and La Niña

2017 ◽  
Vol 197 ◽  
pp. 150-166 ◽  
Author(s):  
Upal Saha ◽  
Devendraa Siingh ◽  
S.K. Midya ◽  
R.P. Singh ◽  
A.K. Singh ◽  
...  
Keyword(s):  
East Asia ◽  
El Niño ◽  
Temporal Variability ◽  
El Nino ◽  
La Niña ◽  
South East Asia ◽  
Convective Activity ◽  
La Nina ◽  
Spatio Temporal

scholarly journals Different El Niño Types and Tropical Cyclone Landfall in East Asia

2012 ◽  
Vol 25 (19) ◽  
pp. 6510-6523 ◽  
Author(s):  
Wei Zhang ◽  
H.-F. Graf ◽  
Yee Leung ◽  
Michael Herzog
Keyword(s):  
Tropical Cyclone ◽  
East Asia ◽  
El Niño ◽  
El Nino ◽  
The Philippines ◽  
La Niña ◽  
Malay Peninsula ◽  
Cp El Niño ◽  
La Nina ◽  
Ep El Niño

Abstract This study examines whether there exist significant differences in tropical cyclone (TC) landfall between central Pacific (CP) El Niño, eastern Pacific (EP) El Niño, and La Niña during the peak TC season (June–October) and how and to what extent CP El Niño influences TC landfall over East Asia for the period 1961–2009. The peak TC season is subdivided into summer [June–August (JJA)] and autumn [September–October (SO)]. The results are summarized as follows: (i) during the summer of CP El Niño years, TCs are more likely to make landfall over East Asia because of a strong easterly steering flow anomaly induced by the westward shift of the subtropical high and northward-shifted TC genesis. In particular, TCs have a greater probability of making landfall over Japan and Korea during the summer of CP El Niño years. (ii) In the autumn of CP El Niño years, TC landfall in most areas of East Asia, especially Indochina, the Malay Peninsula, and the Philippines, is likely to be suppressed because the large-scale circulation resembles that of EP El Niño years. (iii) During the whole peak TC season [June–October (JJASO)] of CP El Niño years, TCs are more likely to make landfall over Japan and Korea. TC landfall in East Asia as a whole has an insignificant association with CP El Niño during the peak TC season. In addition, more (less) TCs are likely to make landfall in China, Indochina, the Malay Peninsula, and the Philippines during the peak TC season of La Niña (EP El Niño) years.

scholarly journals ENSO Effect on Interannual Variability of Spring Aerosols over East Asia

2020 ◽  
Author(s):  
Anbao Zhu ◽  
Haiming Xu ◽  
Jiechun Deng ◽  
Jing Ma ◽  
Shuhui Li
Keyword(s):  
East Asia ◽  
Interannual Variability ◽  
El Niño ◽  
El Nino ◽  
Transport Processes ◽  
La Niña ◽  
Carbonaceous Aerosol ◽  
Indochina Peninsula ◽  
Central Pacific ◽  
La Nina

Abstract. Effects of the El Niño/Southern Oscillation (ENSO) on the interannual variability of spring aerosols over East Asia are investigated using the Modern Era Retrospective analysis for Research and Applications Version 2 (MERRA-2) reanalysis aerosol data. Results show that the ENSO has a crucial effect on the spring aerosols over the Indochina Peninsula, southern China and the ocean south of Japan. The above-normal (below-normal) aerosols are found over these regions during the El Niño (La Niña) ensuing spring. In contrast to the local aerosol diffusion in winter, the ENSO affects East Asian aerosols in the following spring mainly via modulating upstream aerosol generation and transport processes. The underlying physical mechanism is that during the El Niño (La Niña) ensuing spring, the dry (wet) air and less (more) precipitation are beneficial for the increase (reduction) of biomass burning activities over the northern Indochina Peninsula, resulting in more (less) carbonaceous aerosol emissions. On the other hand, the anomalous anticyclone (cyclone) over the western North Pacific (WNP) associated with El Niño (La Niña) enhances (weakens) the low-level southwesterly wind from the northern Indochina Peninsula to southern Japan, which transports more (less) carbonaceous aerosol downstream. Anomalous precipitation plays a role in reducing aerosols over the source region, but its washout effect over the downstream region is limited. The ENSO’s impact on the ensuing spring aerosols is mainly attributed to the eastern Pacific ENSO rather than the central Pacific ENSO.

scholarly journals Impacts of ENSO On The Seasonal Transition From Summer to Winter in East Asia

2021 ◽  
Author(s):  
Sunyong Kim ◽  
Jong-Seong Kug
Keyword(s):  
East Asia ◽  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Southern Oscillation ◽  
Temperature Drop ◽  
La Niña ◽  
Boreal Summer ◽  
Seasonal Transition ◽  
La Nina

Abstract The El Niño-Southern Oscillation (ENSO) has seasonally distinct impacts on the East Asian climate so that its seasonal transition depends on the phases of El Niño and La Niña. Here, we investigate the seasonal transition of surface temperature in East Asia from boreal summer to winter based on the warm/cold ENSO developing phases. During La Niña years, from summer to winter the continuous temperature drop in East Asia tends to be faster than that during El Niño, indicating a latter start and earlier termination of fall. This different seasonal transition in East Asia according to phases of ENSO is mostly explained by atmospheric responses to the seasonally-dependent tropical/subtropical precipitation forcings in ENSO developing phases. The anomalous positive precipitation in the subtropical North Pacific exists only in September and leads to the subtropical cyclonic flow during El Niño years. The resultant northerly anomalies on the left side of subtropical cyclone are favorable for transporting cold advection towards East Asia. However, the positive subtropical precipitation disappears and teleconnection to East Asia is strongly controlled by the negative precipitation anomalies in the western North Pacific, modulating the anticyclonic anomalies in East Asia during the early winter (November). Therefore, these seasonally sharp precipitation changes associated with ENSO evolution induce distinctive teleconnection changes from northerly (summer) to southerly (winter) anomalies, which eventually affect seasonal transition in East Asia. Also, the Coupled Model Intercomparison Project Phase 5 models reasonably simulate the relatively rapid temperature transition in East Asia during La Niña years, supporting the observational argument.

scholarly journals The 10–20 d Low-Frequency Oscillation Characteristics of Summer Precipitation in Eastern China in the Decaying Year of CP ENSO

Atmosphere ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 616
Author(s):  
Cong Cai ◽  
Lijuan Wang ◽  
Junyu Wang ◽  
Zhiqiang Wang
Keyword(s):  
El Niño ◽  
El Nino ◽  
Eastern China ◽  
Low Frequency ◽  
Summer Precipitation ◽  
La Niña ◽  
Low Frequency Oscillation ◽  
Cp El Niño ◽  
La Nina ◽  
Oscillation Characteristics

Using National Centers for Atmospheric Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data and observational data, the low-frequency oscillation characteristics of precipitation in eastern China during the decaying summer of central Pacific El Niño–Southern Oscillation (CP ENSO) and the corresponding low-frequency atmospheric oscillation characteristic were investigated. The results showed that summer precipitation in eastern China during the decaying year of CP El Niño (La Niña) was more (less) than the climatological mean and that 10–20 d was its dominant period. Low-frequency oscillations at different tropospheric levels had different effects on low-frequency precipitation. In the upper troposphere, Eastern China was dominated by low-frequency divergence and positive (negative) anomaly of low-frequency height during the decaying year of CP El Niño (La Niña), and there was strong (weak) northwest–southeast wave-active flux transport. In the middle troposphere, the range and intensity of the subtropical western Pacific High (SWPH) of CP El Niño was larger and stronger than that of CP La Niña, which may be related to the low-frequency height fields. Meanwhile, the correspnding low-frequency wind field, water vapor circulation systems and moisture transport channels in the lower troposphere, along with the low-frequency vertical movement were significantly different, causing the low-frequency precipitation of CP El Niño to be stronger than CP La Niña.

scholarly journals Contrasting impacts of two types of El Niño events on winter haze days in China's Jing-Jin-Ji region

2020 ◽  
Author(s):  
Xiaochao Yu ◽  
Zhili Wang ◽  
Hua Zhang ◽  
Jianjun He ◽  
Ying Li
Keyword(s):  
El Niño ◽  
El Nino ◽  
Eastern China ◽  
Cp El Niño ◽  
El Niño Event ◽  
Haze Pollution ◽  
El Niño Events ◽  
Ep El Niño ◽  
Haze Days ◽  
El Nino Events

Abstract. El Niño is a complex system with diverse distribution features and intensities. The regional climate anomalies caused by different types of El Niño event likely lead to various impacts on winter haze pollution in China. Based on long-term site observations of haze days in China from 1961 to 2013, this study explores the effects of Eastern Pacific (EP) and Central Pacific (CP) types of El Niño event on winter haze days (WHD) in China's Jing-Jin-Ji (JJJ) region and the physical mechanisms underlying WHD changes. The results show statistically significant positive and negative correlations, respectively, between WHD in the JJJ region and EP and CP El Niño events. At most sites in the JJJ region, the average WHD are increased in all EP El Niño years, with the maximum change exceeding 2.0 days. Meanwhile the average WHD are decreased at almost all stations over this region in all CP El Niño years, with the largest change being more than −2.0 days. The changes in large-scale circulations indicate obviously positive surface air temperature (SAT) anomalies and negative sea level pressure (SLP) anomalies over North China, and southerly wind anomalies at the mid-low troposphere over eastern China in the winters of EP El Niño years. These anomalies are conducive to increases in WHD in the JJJ region. However, there are significant northerly and northwesterly wind anomalies at the mid-low troposphere over eastern China, and stronger and wider precipitation anomalies in the winters of CP El Niño years, which contribute to decreased WHD over the JJJ region. Changes in local synoptic conditions indicate negative SLP anomalies, positive SAT anomalies, and weakened northerly winds over the JJJ region in the winters of EP El Niño years. The occurrence frequency of circulation types conducive to the accumulation (diffusion) of aerosol pollutants is increased (decreased) by 0.4 % (0.37 %) in those winters. However, the corresponding frequency is decreased (increased) by 0.54 % (0.56 %) in the winters of CP El Niño years. Our study highlights the importance of distinguishing the impacts of two types of El Niño events on winter haze pollution in China's JJJ region.

scholarly journals Contrasting impacts of two types of El Niño events on winter haze days in China's Jing-Jin-Ji region

2020 ◽  
Vol 20 (17) ◽  
pp. 10279-10293
Author(s):  
Xiaochao Yu ◽  
Zhili Wang ◽  
Hua Zhang ◽  
Jianjun He ◽  
Ying Li
Keyword(s):  
El Niño ◽  
El Nino ◽  
Eastern China ◽  
Cp El Niño ◽  
Haze Pollution ◽  
Synoptic Conditions ◽  
El Niño Events ◽  
Ep El Niño ◽  
Haze Days ◽  
El Nino Events

Abstract. El Niño events differ widely in their patterns and intensities. The regional climate anomalies caused by different types of El Niño events likely lead to various impacts on winter haze pollution in China. Based on long-term site observations of haze days in China from 1961 to 2013, this study explores the effects of eastern Pacific (EP) and central Pacific (CP) types of El Niño events on the number of winter haze days (WHDs) in China's Jing-Jin-Ji (JJJ) region and the physical mechanisms underlying WHD changes. The results show statistically significant positive and negative correlations, respectively, between WHDs in the JJJ region and EP and CP El Niño events. At most sites in the JJJ region, the average WHD increased in all EP El Niño years, with the maximum change exceeding 2.0 d. Meanwhile, the average WHD decreased at almost all stations over this region in all CP El Niño years, with the largest change being more than −2.0 d. The changes in large-scale circulations indicate obvious positive surface air temperature (SAT) anomalies and negative sea level pressure (SLP) anomalies over North China, as well as southerly wind anomalies at the middle to low troposphere over eastern China in the winters of EP El Niño years. These anomalies are conducive to increases in WHDs in the JJJ region. However, there are significant northerly and northwesterly wind anomalies at the middle to low troposphere over eastern China, as well as stronger and wider precipitation anomalies in the winters of CP El Niño years, which contribute to decreased WHDs over the JJJ region. Changes in local synoptic conditions indicate negative SLP anomalies, positive SAT anomalies, and weakened northerly winds over the JJJ region in the winters of EP El Niño years. The total occurrence frequency of circulation types conducive to the accumulation (diffusion) of aerosol pollutants is increased (decreased) by 0.4 % (0.2 %) in those winters. However, the corresponding frequency is decreased (increased) by 0.5 % (0.6 %) in the winters of CP El Niño years. Our study highlights the importance of distinguishing the impacts of these two types of El Niño events on winter haze pollution in China's JJJ region.

Sign in / Sign up

Export Citation Format

Share Document