scholarly journals Effects of Large Volcanic Eruptions on Global Summer Climate and East Asian Monsoon Changes during the Last Millennium: Analysis of MPI-ESM Simulations

2014 ◽  
Vol 27 (19) ◽  
pp. 7394-7409 ◽  
Author(s):  
Wenmin Man ◽  
Tianjun Zhou ◽  
Johann H. Jungclaus
Keyword(s):  
East Asia ◽  
East Asian Monsoon ◽  
East Asian ◽  
Eastern China ◽  
Lower Troposphere ◽  
Volcanic Eruptions ◽  
Shortwave Radiation ◽  
Radiative Energy ◽  
Tropical Ocean ◽  
Large Volcanic Eruptions

Abstract Responses of summer [June–August (JJA)] temperature and precipitation to large volcanic eruptions are analyzed using the millennial simulations of the earth system model developed at the Max Planck Institute for Meteorology. The model was driven by up-to-date reconstructions of external forcing, including natural forcing (solar and volcanic) and anthropogenic forcing (land-cover change and greenhouse gases). Cooling anomalies after large volcanic eruptions are seen on a nearly global scale. The cooling in the Northern Hemisphere (NH) is stronger than in the Southern Hemisphere (SH), and cooling is stronger over the continents than over the oceans. The precipitation decreases in the tropical and subtropical regions in the first summer after large volcanic eruptions. The cooling, with amplitudes of up to −0.6°C, is also seen over eastern China. East Asia is dominated by northerly wind anomalies, and the corresponding summer rainfall exhibits a coherent reduction over the entirety of eastern China. The tropospheric mean temperature anomalies indicate that there is coherent cooling over East Asia and the tropical ocean after large volcanic eruptions. The cooling over the middle-to-high latitudes of East Asia is stronger than over the tropical ocean. This temperature anomaly pattern suggests a reduced land–sea thermal contrast and favors a weaker East Asian summer monsoon (EASM) circulation. Analysis of the radiative fluxes at the top of the atmosphere (TOA) suggests that the reduction in shortwave radiation after large volcanic eruptions is nearly twice as large as the reduction in emitted longwave radiation, a net loss of radiative energy that cools the surface and lower troposphere.

A reconstruction of the East Asian summer monsoon index over the half past millennium

2020 ◽  
Author(s):  
Feng Shi ◽  
Hugues Goosse ◽  
Jianping Li ◽  
Fredrik Charpentier Ljungqvist ◽  
Sen Zhao ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Yangtze River ◽  
East Asian Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Eastern China ◽  
Lower Troposphere ◽  
The Yangtze River ◽  
Asian Summer

<p>The EASM largely determines variations in summer precipitation in the East Asian monsoon region where approximately one-quarter of the world’s population live. A reliable East Asian summer monsoon (EASM) index covering several centuries is important in order to understand EASM dynamics. The wind-field is frequently used to calculate the EASM index during the instrumental period. However, available climate proxy data rather respond to direct precipitation changes. A gridded extended summer (May–September, MJJAS) precipitation reconstruction for China covering AD 1470–2000 is used to indirectly reconstruct two types of EASM indices (defined by the strength of the 850hPa southwesterly winds and a north-south gradient of the zonal winds), using the negative correlation between the EASM index and summer (June–August, JJA) rainfall in the middle and lower reaches of the Yangtze River of China. The two EASM indices are validated by independent historical documentary data for eastern China. The physical processes ruling the EASM variability are explored, highlighting a baroclinic structure over the middle and lower reaches of the Yangtze River. It includes an anticyclonic circulation accompanied by high pressure anomalies in the lower troposphere and a cyclonic circulation with low pressure anomaly in the upper troposphere. This is associated with a decrease in atmospheric water vapor content (due to divergence), which will decrease summer rainfall in the region, and contribute to the strengthen of the EASM variability. The dominated and inter-annual component of the EASM variation is possibly linked to the ‘ENSO-like’ sea surface temperature according to a data assimilation experiment performed with the Community Earth System Model-Last Millennium Ensemble (CESM-LME) simulation.</p>

Summertime surface ozone variation over East Asia in CCMI

2020 ◽  
Author(s):  
Jieun Wie ◽  
Hyo-Jin Park ◽  
Hyomee Lee ◽  
Byung-Kwon Moon
Keyword(s):  
East Asia ◽  
Climate Model ◽  
Southern Oscillation ◽  
Surface Ozone ◽  
Eastern China ◽  
Empirical Orthogonal Functions ◽  
Ozone Production ◽  
Shortwave Radiation ◽  
Horizontal Wind ◽  
Second Mode

<p>The concentration of surface ozone in East Asia is high due to strong solar radiation, but decreases in areas affected by summer monsoons. This study analyzes the summer surface ozone variations in East Asia using meteorological and atmospheric chemistry variables in 12 models participating in Chemistry-Climate Model Initiative (CCMI) for the period of 1979 to 2010. The concentration of 850 hPa ozone was identified two modes by Empirical Orthogonal Functions (EOF) analysis. The first mode is an increase in all regions over East Asia, mainly in eastern China. This mode was associated with downward wind, weak horizontal wind speed, increase in temperatures, decrease in precipitation. The second mode showed high ozone concentrations in eastern China and low in northern Japan. In eastern China, temperatures and precipitation are decreased, and shortwave radiation reaches the surface is increased. In addition, the concentration of nitrogen oxides and carbon monoxide and the net ozone production are increased. The second mode was highly correlated with El Nino-Southern Oscillation (ENSO) and western North Pacific subtropical high (WNPSH) indices and was found to be closely associated with East Asian summer monsoons.</p><p> </p><p>Acknowledgements: This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2019R1A2C1008549). We acknowledge the modeling groups for making their simulations available for this analysis, the joint WCRP SPARC/IGAC Chemistry–Climate Model Initiative (CCMI) for organizing and coordinating the model simulations and data analysis activity, and the British Atmospheric Data Centre (BADC) for collecting and archiving the CCMI model output.</p>

The teleconnection between the Siberian snow-albedo feedback and the spring East Asian dust cycle : based on Last Millennium Ensemble

2020 ◽  
Author(s):  
Heng Liu
Keyword(s):  
East Asian ◽  
Lower Troposphere ◽  
Reanalysis Data ◽  
Asian Dust ◽  
Shortwave Radiation ◽  
Last Millennium ◽  
Albedo Feedback ◽  
Snow Albedo ◽  
The Past ◽  
Westerly Winds

<p>According to the reanalysis data of recent years, the Siberian snow-albedo feedback is found to play a crucial role on the spring East Asian dust cycle by influence local energy budget and circulation. By analyzing the CESM Last Millennium Ensemble conducted by National Center for Atmospheric Research (NCAR), we found that the spring East Asian dust burden is significantly correlated with the snow-albedo over Siberia during the past millennium. The correlation coefficient between the snow depth over Siberia and the East Asian dust burden reaches to 0.56. The cloud fraction over Siberia is also correlated with the dust burden with a coefficient of 0.40. The Siberian snow cover reflects shortwave radiation and cools down the lower and middle troposphere, which leads to more clouds and snows occurring over Siberia. The increased cloud cover therefore reflects more shortwave to cool down the surface as a positive feedback. The cooling of lower troposphere over Siberia induces cyclonic wind anomalies around the region, enhances the westerly winds over the East Asian deserts which locate on the south side of Siberia and finally promotes the East Asian dust cycle.</p>

Coupling of South and East Asian Monsoon Precipitation in July–August*

2015 ◽  
Vol 28 (11) ◽  
pp. 4330-4356 ◽  
Author(s):  
Jesse A. Day ◽  
Inez Fung ◽  
Camille Risi
Keyword(s):  
East Asia ◽  
South Asia ◽  
Bay Of Bengal ◽  
Moisture Transport ◽  
Asian Monsoon ◽  
East Asian Monsoon ◽  
Southern China ◽  
East Asian ◽  
Monsoon Circulation ◽  
Yunnan Plateau

Abstract The concept of the “Asian monsoon” masks the existence of two separate summer rainfall régimes: convective storms over India, Bangladesh, and Nepal (the South Asian monsoon) and frontal rainfall over China, Japan, and the Korean Peninsula (the East Asian monsoon). In addition, the Himalayas and other orography, including the Arakan Mountains, Ghats, and Yunnan Plateau, create smaller precipitation domains with abrupt boundaries. A mode of continental precipitation variability is identified that spans both South and East Asia during July and August. Point-to-point correlations and EOF analysis with Asian Precipitation–Highly-Resolved Observational Data Integration Toward Evaluation of the Water Resources (APHRODITE), a 57-yr rain gauge record, show that a dipole between the Himalayan foothills (+) and the “monsoon zone” (central India, −) dominates July–August interannual variability in South Asia, and is also associated in East Asia with a tripole between the Yangtze corridor (+) and northern and southern China (−). July–August storm tracks, as shown by lag–lead correlation of rainfall, remain mostly constant between years and do not explain this mode. Instead, it is proposed that interannual change in the strength of moisture transport from the Bay of Bengal to the Yangtze corridor across the northern Yunnan Plateau induces widespread precipitation anomalies. Abundant moisture transport along this route requires both cyclonic monsoon circulation over India and a sufficiently warm Bay of Bengal, which coincide only in July and August. Preliminary results from the LMDZ version 5 (LMDZ5) model, run with a zoomed grid over Asia and circulation nudged toward the ECMWF reanalysis, support this hypothesis. Improved understanding of this coupling may help to project twenty-first-century precipitation changes in East and South Asia, home to over three billion people.

scholarly journals Large volcanic eruptions cause drought in eastern China

Eos ◽  
2014 ◽  
Vol 95 (37) ◽  
pp. 340-340
Author(s):  
Colin Schultz
Keyword(s):  
Eastern China ◽  
Volcanic Eruptions ◽  
Large Volcanic Eruptions

scholarly journals Inter-annual variation of aerosol pollution in East Asia and its relation with strong/weak East Asian winter monsoon

2017 ◽  
Author(s):  
Min Xie ◽  
Lei Shu ◽  
Tijian Wang ◽  
Da Gao ◽  
Shu Li ◽  
...  
Keyword(s):  
East Asia ◽  
Annual Variation ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Lower Troposphere ◽  
Northerly Wind ◽  
Asian Winter Monsoon ◽  
The North ◽  
Change Pattern ◽  
Aerosol Pollution

Abstract. Aerosol has become one of the major air pollutants in East Asia, and its spatial distribution can be affected by the East Asian monsoon circulation. By means of the observational analysis and the numerical simulation, the inter-annual variation of wintertime aerosol pollution in East Asia and its association with strong/weak East Asian winter monsoon (EAWM) are investigated in this study. Firstly, the Moderate Resolution Imaging Spectroradiometer/Aerosol Optical Depth (MODIS/AOD) records during 2000–2013 are analyzed to reveal the inter-annual variation characteristics of aerosols. It is found that there is an increasing trend of AOD in East Asia over the last decade, implying the increasing aerosol loading in this region. The areas with obvious increasing AOD cover the Sichuan Basin (SCB), the North China Plain, and most of the Middle-Lower Yangtze River Plain in China. Secondly, the EAWM index (EAWMI) based on the characteristic of circulation are calculated to investigate the inter-annual variations of EAWM. The National Centers for Environmental Prediction (NCEP) reanalysis data are used in EAWMI calculation and meteorological analysis. Nine strong and thirteen weak EAWM years are identified from 1979 to 2014. In these strong EAWM years, the sea-land pressure contrast increases, the East Asian trough strengthens, and the northerly wind gets anomalous over East Asia. More cold air masses are forced to move southward by strengthened wind field and make cool. In the weak EAWM years, however, the situation is totally on the opposite. Finally, the effects of strong/weak EAWM on the distribution of aerosols in East Asia are discussed. It is found that the northerly wind strengthens (weakens) and transports more (less) aerosols southward in strong (weak) EAWM years, resulting in higher (lower) AOD in the north and lower (higher) AOD in the south. The long-term weakening trend of EAWM may potentially increase the aerosol loading. Apart from the changes in aerosol emissions, the weakening of EAWM should be another cause that results in the increase of AOD over the Yangtze River Delta (YRD) region, the Beijing-Tianjin-Hebei (BTH) region and SCB but the decrease of AOD over the Pearl River Delta (PRD) region. Using the Regional Climate-Chemistry coupled Model System (RegCCMS), we further prove that the intensity of EAWM has great impacts on the spatial distribution of aerosols. In strong (weak) EAWM years, there is a negative (positive) anomaly in the air column content of aerosol, with a reduction (increment) of −80 (25) mg m−2. The change pattern of aerosol concentrations in lower troposphere is different from that at 500 hPa, which is related with the different change pattern of meteorological fields in EAWM circulation at different altitude. More obvious changes occur in lower atmosphere, the change pattern of aerosol column content in different EAWM years is mainly decided by the change of aerosols in lower troposphere.

Changes in Tibetan Plateau latitude as an important factor for understanding East Asian climate since the Eocene: A modeling study 

2021 ◽  
Author(s):  
Ran Zhang ◽  
Dabang Jiang ◽  
Gilles Ramstein ◽  
Zhongshi Zhang ◽  
Peter C Lippert ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
East Asia ◽  
Climate Modeling ◽  
East Asian Monsoon ◽  
East Asian ◽  
Surface Uplift ◽  
Latitudinal Position ◽  
East Asian Climate ◽  
The Tropics ◽  
The Himalaya

<p><span>Previous climate modeling studies suggest that the surface uplift of the Himalaya–Tibetan plateau (TP) is a crucial parameter for the onset and intensification of the East Asian monsoon during the Cenozoic. Most of these studies have only considered the Himalaya–TP in its present location between ∼26°N and ∼40°N despite numerous recent geophysical studies that reconstruct the Himalaya–TP 10° or more of latitude to the south during the early Paleogene. We have designed a series of climate simulations to explore the sensitivity of East Asian climate to the latitude of the Himalaya–TP. Our simulations suggest that the East Asian climate strongly depends on the latitude of the Himalaya–TP. Surface uplift of a proto-Himalaya–TP in the subtropics intensifies aridity throughout inland Asia north of ∼40°N and enhances precipitation over East Asia. In contrast, the rise of a proto-Himalaya–TP in the tropics only slightly intensifies aridity in inland Asia north of ∼40°N, and slightly increases precipitation in East Asia. Importantly, this climate<br>sensitivity to the latitudinal position of the Himalaya–TP is non-linear, particularly for precipitation across East Asia.</span></p>

Impact of atmospheric quasi-biweekly oscillation on the persistent heavy PM2.5 pollution over Beijing-Tianjin-Hebei region, China during winter

2020 ◽  
Author(s):  
Libo Gao ◽  
Tijian Wang ◽  
Xuejuan Ren ◽  
Bingliang Zhuang ◽  
Shu Li ◽  
...  
Keyword(s):  
Time Scale ◽  
Wave Train ◽  
Fine Particulate Matter ◽  
East Asian ◽  
Eastern China ◽  
Lower Troposphere ◽  
Stable Stratification ◽  
East Asian Trough ◽  
Asian Winter Monsoon ◽  
Bth Region

<p>In recent years, persistent heavy air pollution (PHP) events occurred frequently over the Beijing-Tianjin-Hebei (BTH) region in China, which posed a great threat to human health. The pollution was characterized by fine particulate matter smaller than 2.5 μm in diameter (PM<sub>2.5</sub>). This study investigates the evolution of PHP over the BTH region and its relation to the atmospheric quasi-biweekly oscillation in winters of 2013–2017. A PHP event is defined as three or more consecutive days with daily mean PM<sub>2.5</sub> concentration exceeding 150 μg m<sup>-3</sup>. We observed a significant periodicity of 10–16 days of the PM<sub>2.5</sub> concentration, which notably contributes to the occurrence of PHP. According to the quasi-biweekly variation of PM<sub>2.5</sub>, the life cycle of PHP events are divided into eight phases. The phase composites of circulation anomalies show that the atmospheric quasi-biweekly oscillation provides favorable conditions for the persistence of wintertime PM<sub>2.5</sub> pollution. During the PHP events, the quasi-biweekly southerly anomalies prevail persistently over eastern China. The East Asian winter monsoon is weakened and more moisture is transported to the BTH region continuously. The anomalous warming in the lower troposphere indicates a stable stratification on the quasi-biweekly time scale. In the mid-troposphere, the oscillation of East Asian trough’s intensity is significantly correlated with the PHP events. Further lead-lag correlation analysis suggested that the quasi-biweekly oscillation of East Asian trough can be traced back to a precursor signal over northwestern Eurasia about 11 days earlier, through a southeastward wave train propagation. Therefore, the meteorological conditions conducive to PHP over the BTH region can be predicted on the quasi-biweekly time scale.</p>

Sign in / Sign up

Export Citation Format

Share Document