scholarly journals Foreign influences on tropospheric ozone over East Asia through global atmospheric transport

2019 ◽  
Author(s):  
Han Han ◽  
Jane Liu ◽  
Huiling Yuan ◽  
Tijian Wang ◽  
Bingliang Zhuang ◽  
...  
Keyword(s):  
East Asia ◽  
South Asian ◽  
North American ◽  
Tropospheric Ozone ◽  
Surface Ozone ◽  
East Asian ◽  
South Asian High ◽  
Interannual Variations ◽  
Upper Troposphere ◽  
Strong Seasonality

Abstract. Tropospheric ozone in East Asia is influenced by the transport of ozone from foreign regions around the world. However, the magnitudes and variations of such influences remain unclear. This study was performed to investigate this influence and its variations with space and time using a global chemical transport model, GEOS-Chem, for emission zero-out and tagged ozone simulations. The results show that foreign ozone varies significantly with latitude, altitude, and season in the East Asian troposphere. The transport of foreign ozone to East Asia occurs primarily through the middle and upper troposphere, where the concentration of foreign ozone (32–65 ppbv) in East Asia is 0.5–6 times higher than that of native ozone (11–18 ppbv) and has strong seasonality, being largest in spring and lowest in winter. Foreign ozone in East Asia increases rapidly with altitude. At the surface, the annual average foreign ozone concentration is ~ 22.2 ppbv, which is comparable to its native counterpart of ~ 20.4 ppbv. The annual mean concentration of anthropogenic ozone from foreign regions is ~ 4.7 ppbv at the East Asian surface, and half of it comes from North America (1.3 ppbv) and Europe (1.0 ppbv). The presence of foreign ozone at the East Asian surface is highest in winter (27.1 ppbv) and lowest in summer (16.5 ppbv). This strong seasonality is largely modulated by the East Asian monsoon (EAM) via its influence on vertical motion. The large-scale subsidence prevailing during the East Asian winter monsoon (EAWM) favours the downdraft of foreign ozone to the surface, while widespread convection in the East Asian summer monsoon (EASM) blocks such transport. In summer, the South Asian High facilitates the build-up of South Asian ozone in the East Asian upper troposphere and constrains North American, European, and African ozone to the regions north of 35° N. The interannual variations of foreign ozone at the East Asian surface have been found to be closely related to the EAM. When the EAWM is strong, North American and European ozone are enhanced at the East Asian surface, as the subsidence behind the East Asian trough becomes stronger. In strong EASM years, South and Southeast Asian ozone is reduced at the East Asian surface due to weakened south-westerly monsoon wind. This study suggests substantial foreign influences on tropospheric ozone in East Asia and underscores the importance of the EAM in the seasonal and interannual variations of foreign influences on surface ozone in East Asia.

scholarly journals Foreign influences on tropospheric ozone over East Asia through global atmospheric transport

2019 ◽  
Vol 19 (19) ◽  
pp. 12495-12514 ◽  
Author(s):  
Han Han ◽  
Jane Liu ◽  
Huiling Yuan ◽  
Tijian Wang ◽  
Bingliang Zhuang ◽  
...  
Keyword(s):  
North America ◽  
East Asia ◽  
Tropospheric Ozone ◽  
Large Scale ◽  
Transport Model ◽  
Surface Ozone ◽  
East Asian ◽  
South Asian High ◽  
Upper Troposphere ◽  
Ozone Concentrations

Abstract. Tropospheric ozone in East Asia is influenced by the transport of ozone from foreign regions around the world. However, the magnitudes and variations in such influences remain unclear. This study was performed to investigate the influences using a global chemical transport model, GEOS-Chem, through the tagged ozone and emission perturbation simulations. The results show that foreign ozone is transported to East Asia (20–60∘ N, 95–150∘ E) mainly through the middle and upper troposphere. In East Asia, the influence of foreign ozone increases rapidly with altitude. In the middle and upper troposphere, the regional mean concentrations of foreign ozone range from 32 to 65 ppbv, being 0.8–4.8 times higher than its native counterpart (11–18 ppbv). Annually, ∼60 % of foreign ozone in the East Asian middle and upper troposphere comes from North America (5–13 ppbv) and Europe (5–7 ppbv), as well as from foreign oceanic regions (9–21 ppbv). Over the East Asian tropospheric columns, foreign ozone appears most in spring when ozone concentrations in the foreign regions are high and the westerlies are strong and least in summer when the South Asian High blocks eastward foreign ozone from reaching East Asia south of 35∘ N. At the East Asian surface, the annual mean of foreign ozone concentrations is ∼22.2 ppbv, which is comparable to its native counterpart of ∼20.4 ppbv. In the meantime, the annual mean of anthropogenic ozone concentrations from foreign regions is ∼4.7 ppbv, half of which comes from North America (1.3 ppbv) and Europe (1.0 ppbv). Seasonally, foreign ozone concentrations at the East Asian surface are highest in winter (27.1 ppbv) and lowest in summer (16.5 ppbv). This strong seasonality is largely modulated by the East Asian monsoon (EAM) via its influence on vertical motion. The large-scale subsidence prevailing during the East Asian winter monsoon (EAWM) favours the downdraft of foreign ozone to the surface, while widespread convection in the East Asian summer monsoon (EASM) blocks such transport. Interannually, the variation in foreign ozone at the East Asian surface is found to be closely related to the intensity of the EAM. Specifically, the stronger the EAWM is in a winter, the more ozone from North America and Europe reaches the East Asian surface because of the stronger subsidence behind the East Asian trough. In summer, ozone from South and South-east Asia is reduced in strong EASM years due to weakened south-westerly monsoon winds. This study suggests substantial foreign influences on ozone at the East Asian surface and in its tropospheric columns. It also underscores the importance of the EAM in the seasonal and interannual variations in foreign influences on surface ozone in East Asia.

Impact of East Asian Summer Monsoon Heating on the Interannual Variation of the South Asian High

2015 ◽  
Vol 29 (1) ◽  
pp. 159-173 ◽  
Author(s):  
Pengfei Zhang ◽  
Yimin Liu ◽  
Bian He
Keyword(s):  
Middle East ◽  
South Asian ◽  
East Asian Summer Monsoon ◽  
Geopotential Height ◽  
Interannual Variation ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
South Asian High ◽  
Upper Troposphere ◽  
Asian Summer

Abstract Occupying the upper troposphere over subtropical Eurasia during boreal summer, the South Asian high (SAH) is thought to be a regulator of the East Asian summer monsoon (EASM), which is particularly important for regional climate over Asia. However, there is feedback of the condensational heating associated with EASM precipitation to SAH variability. In this study, interannual variation of SAH intensity and the mechanisms are investigated. For strong SAH cases, the high pressure system intensifies and expands. Significant positive anomalies of the geopotential height and upper-tropospheric temperature were found over the Middle East and to the east of the Tibetan Plateau (TP), namely, the western and the eastern flanks of the SAH. The dynamical diagnosis and the numerical experiments consistently show that the interannual variation of SAH intensity is strongly affected by EASM precipitation over the eastern TP–Yangtze River valley. The feedback of the condensational heating anomaly to the SAH is summarized as follows: Excessive EASM heating excites a local anticyclone in the upper troposphere and warms the upper troposphere, leading to the eastward extension of the SAH’s eastern edge and reinforcing geopotential height anomalies over East Asia. Furthermore, the monsoonal heating excites a westward-propagating Rossby wave that increases the upper-tropospheric geopotential height and warms the upper troposphere over the Middle East. In conclusion, this study suggests a mechanistic paradigm in which the EASM may also be a modulator of SAH variation rather than just a passive result of the latter as traditionally thought. The results suggest that the EASM and the SAH are a tightly interactive system.

Is there interdecadal variation in the South Asian High?

2021 ◽  
pp. 1-46
Author(s):  
Dapeng Zhang ◽  
Yanyan Huang ◽  
BoTao Zhou ◽  
Huijun Wang
Keyword(s):  
South Asian ◽  
Geopotential Height ◽  
Yangtze River ◽  
North China ◽  
East Asian ◽  
Northwest Pacific ◽  
South Asian High ◽  
The Yangtze River ◽  
The South ◽  
Upper Troposphere

AbstractThe decadal intensification of the South Asian High (SAH) after the late 1970s, which is determined based on the geopotential height (H), is suspicious due to the lifting effect upon H caused by global warming. The updated reanalysis datasets of ERA5 and JRA55 indicate that the anticyclone in the upper troposphere over the Tibetan Plateau is relatively weak during 1980–2018 compared to that during 1950–1979. This decadal weakening of the SAH after 1979 can also be observed in the radiosonde observation data. Correspondingly, the SAH defined by eddy geopotential height (H’) reflects a consistent decadal weakening variation. The decadal weakening of SAH detected from H’ after the late 1970s matches with a decadal southward shift of the East Asian Westerly Jet, causing ascending motions over the Yangtze River Valley and descending motions over North China. Moreover, the decadal weakening and westward shift of the SAH is accompanied with the positive relative vorticity anomalies over the Northwest Pacific in the upper troposphere, which implies a declining and eastward shift of the western Pacific subtropical high (WPSH) and a weakened East Asian Summer Monsoon (EASM). Hence, the decadal weakening of the SAH after the late 1970s may contribute to the Yangtze-River-flooding-and-North-China-drought pattern through its connection with other circulation systems of EASM.

Economic Implications of Asian Integration

2008 ◽  
Vol 8 (3) ◽  
pp. 1850139 ◽  
Author(s):  
Joseph F. Francois ◽  
Ganeshan Wignaraja
Keyword(s):  
East Asia ◽  
South Asian ◽  
Regional Integration ◽  
East Asian ◽  
The South ◽  
Economic Implications ◽  
Spider Web ◽  
Integration Schemes ◽  
Asian Economies ◽  
Northeast Asian

The Asian countries are once again focused on options for large, comprehensive regional integration schemes. In this paper we explore the implications of such broad-based regional trade initiatives in Asia, highlighting the bridging of the East and South Asian economies. We place emphasis on the alternative prospects for insider and outsider countries. We work with a global general equilibrium model of the world economy, benchmarked to a projected 2017 sets of trade and production patterns. We also work with gravity-model based estimates of trade costs linked to infrastructure, and of barriers to trade in services. Taking these estimates, along with tariffs, into our CGE model, we examine regionally narrow and broad agreements, all centered on extending the reach of ASEAN to include free trade agreements with combinations of the northeast Asian economies (PRC, Japan, Korea) and also the South Asian economies. We focus on a stylized FTA that includes goods, services, and some aspects of trade cost reduction through trade facilitation and related infrastructure improvements. What matters most for East Asia is that China, Japan, and Korea be brought into any scheme for deeper regional integration. This matter alone drives most of the income and trade effects in the East Asia region across all of our scenarios. The inclusion of the South Asian economies in a broader regional agreement sees gains for the East Asian and South Asian economies. Most of the East Asian gains follow directly from Indian participation. The other South Asian players thus stand to benefit if India looks East and they are a part of the program, and to lose if they are not. Interestingly, we find that with the widest of agreements, the insiders benefit substantively in terms of trade and income while the aggregate impact on outside countries is negligible. Broadly speaking, a pan-Asian regional agreement would appear to cover enough countries, with a great enough diversity in production and incomes, to actually allow for regional gains without substantive third-country losses. However, realizing such potential requires overcoming a proven regional tendency to circumscribe trade concessions with rules of origin, NTBs, and exclusion lists. The more likely outcome, a spider web of bilateral agreements, carries with it the prospect of significant outsider costs (i.e. losses) both within and outside the region.

scholarly journals Upper tropospheric CO and O<sub>3</sub> budget during the Asian Summer Monsoon

2016 ◽  
Author(s):  
B. Barret ◽  
B. Sauvage ◽  
Y. Bennouna ◽  
E. Le Flochmoen
Keyword(s):  
South Asian ◽  
Summer Monsoon ◽  
Satellite Data ◽  
Large Scale ◽  
Transport Model ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Gangetic Plain ◽  
Upper Troposphere ◽  
Asian Summer

Abstract. During the Asian Summer Monsoon, the circulation in the Upper Troposphere-Lower Stratosphere (UTLS) is dominated by the Asian Monsoon Anticyclone (AMA). Pollutants convectively uplifted to the upper troposphere are trapped within this anticyclonic circulation that extends from the Pacific Ocean to the eastern Mediterranean basin. Among the uplifted pollutants are ozone (O3) and its precursors, such as carbon monoxide (CO) and nitrogen oxides (NOx). Many studies based on global modelisation and satellite data have documented the source regions and transport pathways of primary pollutants (CO, HCN) into the AMA. Here, we aim to quantify the O3 budget by taking into consideration anthropogenic and natural sources. We first use CO and O3 data from the Metop-A/IASI sensor to document their tropospheric distributions over Asia, taking advantage of the useful information they provide on the vertical dimension. These satellite data are used together with MOZAIC/IAGOS tropospheric profiles recorded in India to validate the distributions simulated by the global GEOS-Chem chemistry transport model. Over the Asian region, UTLS monthly CO and O3 distributions from IASI and GEOS-Chem display the same large-scale features. UTLS CO columns from GEOS-Chem are in agreement with IASI, with a low bias of 11 ± 9% and a correlation coefficient of 0.70. For O3, the model underestimates IASI UTLS columns over Asia by 14 ± 26% but the correlation between both is high (0.94). GEOS-Chem is further used to quantify the CO and O3 budget through sensitivity simulations. For CO, these simulations confirm that South-Asian anthropogenic emissions have a more important impact on enhanced concentrations within the AMA (∼25 ppbv) than East-Asian emissions (∼10 ppbv). The correlation between enhanced emissions over the Indo–gangetic–Plain and monsoon deep convection is responsible for this larger impact. Consistently, South-Asian anthropogenic NOx emissions also play a larger role in producing O3 within the AMA (∼8 ppbv) than East-Asian emissions (∼5 ppbv) but Asian lightning produced NOx are responsible for the largest O3 production (10–14 ppbv). Stratosphere to Troposphere Exchanges (STE) are also important in transporting O3 in the upper part of the AMA.

The Interannual Variability of Summer Upper-Tropospheric Temperature over East Asia

2012 ◽  
Vol 25 (19) ◽  
pp. 6539-6553 ◽  
Author(s):  
Lixia Zhang ◽  
Tianjun Zhou
Keyword(s):  
East Asia ◽  
Interannual Variability ◽  
El Nino ◽  
East Asian ◽  
Vertical Motion ◽  
Teleconnection Pattern ◽  
Asian Continent ◽  
Upper Troposphere ◽  
Sst Anomaly ◽  
Anomalous Cyclone

Abstract By using 55-yr NCEP–NCAR reanalysis data, two dominant interannual variability modes of summer upper-tropospheric (500–200 hPa) temperature over East Asia are identified. The first empirical orthogonal function (EOF1) mode in its positive sign features a monopole cooling anomaly, while the second mode (EOF2) features a meridional dipole mode, with the positive (negative) center located south (north) of 35°N. The EOF1 (EOF2) mode is associated with ENSO developing (decaying) summers. They are the result of dynamical teleconnections remotely induced by ENSO and local moist processes. During the El Niño developing summer, the Indian summer monsoon precipitation decreases and forces the Silk Road teleconnection pattern at 200 hPa, featuring an anomalous cyclone over the East Asian continent. Coupled with the anomalous northerly wind in eastern China at 850 hPa, rainfall over north (south) China is suppressed (enhanced). The anomalous cyclone in the upper troposphere, associated vertical motion, and precipitation contribute to the heat and vorticity balance and maintain the monopole cooling. In the El Niño decaying summer, driven by the combined effects of a local SST anomaly and remote warm SST anomaly forcing from the Indian Ocean, precipitation is reduced over the western Pacific Ocean. Less latent heat is released and forces the Pacific–Japan teleconnection pattern along the East Asian continent, inducing a tripolar rainfall anomaly over East Asia. The tripolar precipitation and vertical motion anomalies and the zonal extended cyclonic anomaly in the upper troposphere provide the heating and momentum flux balance and maintain the temperature anomaly pattern during the ENSO decaying summer.

scholarly journals Success story of controlling COVID-19 in East Asia: lessons for South Asia

2021 ◽  
Vol 12 (8) ◽  
pp. 2316-2342
Author(s):  
Shapan Chandra Majumder ◽  
Mohammad Razaul Karim ◽  
Md. Mamun Miah
Keyword(s):  
East Asia ◽  
South Asia ◽  
South Asian ◽  
Good Governance ◽  
East Asian ◽  
Constant Term ◽  
Asian Countries ◽  
Success Story ◽  
Significance Level ◽  
Adf Test

The novel coronavirus is an issue of life and death. The main purpose of the study is to know the East Asian success story of controlling Covid-19 and identify which strategies could be a lesson for South Asia and to examine the influence of good governance on controlling COVID-19. Total daily cases of COVID-19 are collected from March 10 to June 15 for East Asian and March 4 to June 15 for South Asian countries. ARIMA forecasting, ADF test, stability test, and diagnostic tests are applied. The minimum value of AIC and BIC shows the appropriate model is ARIMA (0, 1, 1) for both regions. In the East and South Asian model, the coefficients of the constant term are -0.759451 and 198.0155, and coefficients of MA (1) are -0.715686 and -0.339701 respectively for both regions. It's significant at a 1% significance level and support our hypotheses that the total daily cases of COVID-19 decreasing into East Asia but increasing into South Asia and prove that the South Asia region has faced a lot of difficulties to tackle COVID-19 as most of the countries have not enough government capacity, weak institutions, limited resources, narrow government reaches to the vulnerable people and corruption compare to East Asian region and no actual strategies are yet noticeable from the governments of South Asia as a result transmission increases day by day. That is why; we think that South Asian countries could take lessons from East Asian countries as these countries are more successful to control COVID-19.

scholarly journals The Genus Pachyma (Syn. Wolfiporia) Reinstated and Species Clarification of the Cultivated Medicinal Mushroom “Fuling” in China

2020 ◽  
Vol 11 ◽  
Author(s):  
Fang Wu ◽  
Shou-Jian Li ◽  
Cai-Hong Dong ◽  
Yu-Cheng Dai ◽  
Viktor Papp
Keyword(s):  
North America ◽  
East Asia ◽  
North American ◽  
Biological Activities ◽  
Phylogenetic Analyses ◽  
East Asian ◽  
New Combination ◽  
Medicinal Mushroom ◽  
Morphological Examination ◽  
Wide Range

The fungus “Fuling” has been used in Chinese traditional medicine for more than 2000 years, and its sclerotia have a wide range of biological activities including antitumour, immunomodulation, anti-inflammation, antioxidation, anti-aging etc. This prized medicinal mushroom also known as “Hoelen” is resurrected from a piece of pre-Linnean scientific literature. Fries treated it as Pachyma hoelen Fr. and mentioned that it was cultivated on pine trees in China. However, this name had been almost forgotten, and Poria cocos (syn. Wolfiporia cocos), originally described from North America, and known as “Tuckahoe” has been applied to “Fuling” in most publications. Although Merrill mentioned a 100 years ago that Asian Pachyma hoelen and North American P. cocos are similar but different, no comprehensive taxonomical studies have been carried out on the East Asian Pachyma hoelen and its related species. Based on phylogenetic analyses and morphological examination on both the sclerotia and the basidiocarps which are very seldomly developed, the East Asian samples of Pachyma hoelen including sclerotia, commercial strains for cultivation and fruiting bodies, nested in a strongly supported, homogeneous lineage which clearly separated from the lineages of North American Wolfiporia cocos and other species. So we confirm that the widely cultivated “Fuling” Pachyma hoelen in East Asia is not conspecific with the North American Wolfiporia cocos. Based on the changes in Art. 59 of the International Code of Nomenclature for algae, fungi, and plants, the generic name Pachyma, which was sanctioned by Fries, has nomenclatural priority (ICN, Art. F.3.1), and this name well represents the economically important stage of the generic type. So we propose to use Pachyma rather than Wolfiporia, and subsequently Pachyma hoelen and Pachyma cocos are the valid names for “Fuling” in East Asia and “Tuckahoe” in North America, respectively. In addition, a new combination, Pachyma pseudococos, is proposed. Furthermore, it seems that Pachyma cocos is a species complex, and that three species exist in North America.

scholarly journals The relative importance of various source regions on East Asian surface ozone

2010 ◽  
Vol 10 (4) ◽  
pp. 9077-9120 ◽  
Author(s):  
T. Nagashima ◽  
T. Ohara ◽  
K. Sudo ◽  
H. Akimoto
Keyword(s):  
East Asia ◽  
Korean Peninsula ◽  
Transport Model ◽  
Surface Ozone ◽  
East Asian ◽  
Large Contribution ◽  
Chemical Transport Model ◽  
Substantial Impact ◽  
Source Regions ◽  
Surface O3

Abstract. The Source-Receptor (S-R) relationship for surface O3 in East Asia is estimated for recent years in this study utilizing the tagged tracer method with a global chemical transport model. The estimation shows the importance of intra-continental transport of O3 inside East Asia as well as the transport of O3 from distant source regions. The model well simulated the absolute concentration and seasonal variation of surface O3 in the East Asian region, and demonstrated significant seasonal difference in the origin of surface O3. More than half of surface O3 is attributable to the O3 transported from distant sources outside of East Asia in the cold season (October to March). In the warm season (April to September), most of the surface O3 is attributed to O3 created within East Asia in most areas of East Asia. The contribution of domestically-created O3 accounts for 20% of surface O3 in Japan and the Korean Peninsula, 40% in North China Plain and around 50% in the southern part of China in spring, which increase greatly in summer. The contribution of China and the Korean Peninsula to Japan are estimated at about 10% and 5%, respectively. A large contribution (20%) of China to the Korean Peninsula is also demonstrated. In the northern and southern part of China, large contribution of over 10% from East Siberia and the Indochina Peninsula are identified, respectively. The contribution of intercontinental transport increases with latitude; it is 21% in Northeast China and 13% in Japan and the Korean Peninsula in spring. As for one-hourly mean surface O3, domestically-created O3 is the main contributor in most areas of East Asia, except for the low O3 class (<30 ppbv), and accounts for more than 50% in very high O3 class (>90 ppbv). The mean relative contribution of China to central Japan was about 10% in every class, but that from the Korean Peninsula is important in all expect the low O3 class. Substantial impact of foreign sources on the exceedance of Japan's AAQS is identified in the high O3 class (60–90 ppbv) in spring.

scholarly journals Potential Influence of Arctic Sea Ice to the Interannual Variations of East Asian Spring Precipitation*

2016 ◽  
Vol 29 (8) ◽  
pp. 2797-2813 ◽  
Author(s):  
Zhiwei Wu ◽  
Xinxin Li ◽  
Yanjie Li ◽  
Yun Li
Keyword(s):  
Sea Ice ◽  
East Asia ◽  
Wave Train ◽  
East Asian ◽  
Arctic Sea Ice ◽  
Interannual Variations ◽  
Spring Precipitation ◽  
Westerly Jet ◽  
Arctic Sea ◽  
Subtropical Westerly Jet

Abstract Arctic sea ice (ASI) and its potential climatic impacts have received increasing attention during the past decades, yet the relevant mechanisms are far from being understood, particularly how anomalous ASI affects climate in midlatitudes. The spring precipitation takes up as much as 30% of the annual total and significantly influences agriculture in East Asia. Here, observed evidence and numerical experiment results show that the ASI variability in the Norwegian Sea and the Barents Sea in the preceding winter is intimately connected with interannual variations of the East Asian spring precipitation (EAP). The former can explain about 14% of the total variance of the latter. The ASI anomalies persist from winter through the ensuing spring and excite downstream teleconnections of a distinct Rossby wave train prevailing over the Eurasian continent. For the reduced ASI, such a wave train pattern is usually associated with an anomalous low pressure center over the Mongolian plateau, which accelerates the East Asian subtropical westerly jet. The intensified subtropical westerly jet, concurrent with lower-level convergence and upper-level divergence, enhances the local convection and consequently favors rich spring precipitation over East Asia. For the excessive ASI, the situation tends to be opposite. Given that seasonal prediction of the EAP remains a challenging issue, the winter ASI variability may provide another potential predictability source besides El Niño–Southern Oscillation.

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