scholarly journals Large-Scale Features Associated with the Frontal Zone over East Asia from Late Summer to Autumn

1988 ◽  
Vol 66 (4) ◽  
pp. 565-579 ◽  
Author(s):  
Jun Matsumoto
Keyword(s):  
East Asia ◽  
Large Scale ◽  
Frontal Zone ◽  
Late Summer

scholarly journals Impact of orbitally-driven seasonal insolation changes on Afro-Asian summer monsoons through the Holocene

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Chi-Hua Wu ◽  
Pei-Chia Tsai
Keyword(s):  
East Asia ◽  
Large Scale ◽  
Late Summer ◽  
Early Summer ◽  
Valuable Insight ◽  
The Holocene ◽  
Upper Troposphere ◽  
Asian Summer ◽  
Seasonal Diversity ◽  
Insight Into

AbstractUnderstanding what drives a shift of the Afro–Asian summer monsoons from the continents to oceanic regions provides valuable insight into climate dynamics, changes, and modeling. Here we use data–model synthesis to focus on the differential seasonal responses of solar insolation and monsoons to orbital changes in the Holocene. We observe coordinated and stepwise seasonal evolution of summer monsoons across the mid-Holocene, suggesting the strengthening of the midlatitude jet stream as a bridge in the upper troposphere. Prior to the mid-Holocene, insolation had decreased considerably in early summer; the continental monsoons migrated southeastward, which corresponded to a more pronounced rainy season in coastal East Asia. In late summer, insolation did not decrease until the mid-Holocene. The continued weakening of the continental monsoons, combined with weakened insolation, rapidly enhanced the intrinsic dynamics over East Asia–Western North Pacific and accelerated a large-scale migration of the monsoon, suggesting orbital control of seasonal diversity.

scholarly journals Systematic Variation in Wintertime Precipitation in East Asia by MJO-Induced Extratropical Vertical Motion

2008 ◽  
Vol 21 (4) ◽  
pp. 788-801 ◽  
Author(s):  
Jee-Hoon Jeong ◽  
Baek-Min Kim ◽  
Chang-Hoi Ho ◽  
Yeon-Hee Noh
Keyword(s):  
East Asia ◽  
Large Scale ◽  
Diabatic Heating ◽  
Daily Precipitation ◽  
Lower Troposphere ◽  
Vertical Motion ◽  
Mean Value ◽  
Asian Countries ◽  
The Indian Ocean ◽  
Omega Equation

Abstract The variations in the wintertime precipitation over East Asia and the related large-scale circulation associated with the Madden–Julian oscillation (MJO) are examined. By analyzing the observed daily precipitation for the period 1974–2000, it is found that the MJO significantly modulates the distribution of precipitation over four East Asian countries; the precipitation rate difference between wet and dry periods over East Asia, when the centers of MJO convective activities are located over the Indian Ocean and western Pacific, respectively, reaches 3–4 mm day−1, which corresponds to the climatological winter-mean value. Composite analysis with respect to the MJO suggests that the MJO–precipitation relation is mostly explained by the strong vertical motion anomalies near an entrance region of the East Asia upper-tropospheric jet and moisture supply in the lower troposphere. To elucidate different dynamic origins of the vertical motion generated by the MJO, diagnostic analysis of a generalized omega equation is adopted. It is revealed that about half of the vertical motion anomalies in East Asia are induced by the quasigeostrophic forcings by the MJO, while diabatic heating forcings explain a very small fraction, less than 10% of total anomalies.

Parts of South-east Asia may adopt nuclear post-2030

2021 ◽  
Keyword(s):  
East Asia ◽  
Nuclear Power ◽  
Large Scale ◽  
East Asian ◽  
Energy Development ◽  
South East Asia ◽  
Asian Countries ◽  
Content Type ◽  
Electricity Grid ◽  
Renewable Energy Development

Significance It is the only country in South-east Asia with a large-scale nuclear plant, although this was never loaded with fuel. Other countries in the region have tentative plans to develop nuclear power programmes. Impacts The current absence of nuclear power programmes will help avert the diversion of capital from renewable energy development in the region. South-east Asian countries with small, non-power reactors, built for research, will try to maintain these facilities. Across the region, the need for electricity grid investment will increase as more decentralised generation sources are deployed.

Late-summer carbon fluxes from Canadian forests and peatlands along an east–west continental transect

2006 ◽  
Vol 36 (3) ◽  
pp. 783-800 ◽  
Author(s):  
Carole Coursolle ◽  
Hank A Margolis ◽  
Alan G Barr ◽  
T Andrew Black ◽  
Brian D Amiro ◽  
...  
Keyword(s):  
Large Scale ◽  
Ecosystem Respiration ◽  
Late Summer ◽  
Ecosystem Productivity ◽  
Diurnal Courses ◽  
Continental Scale ◽  
Young Forest ◽  
C Cycle ◽  
Use Efficiency ◽  
East West

Net ecosystem productivity (NEP) during August 2003 was measured by using eddy covariance above 17 forest and 3 peatland sites along an east–west continental-scale transect in Canada. Measured sites included recently disturbed stands, young forest stands, intermediate-aged conifer stands, mature deciduous stands, mature conifer stands, fens, and an open shrub bog. Diurnal courses of NEP showed strong coherence within the different ecosystem categories. Recently disturbed sites showed the weakest diurnal cycle; and intermediate-aged conifers, the strongest. The western treed fen had a more pronounced diurnal pattern than the eastern shrub bog or the Saskatchewan patterned fen. All but three sites were clearly afternoon C sinks. Ecosystem respiration was highest for the young fire sites. The intermediate-aged conifer sites had the highest maximum NEP (NEPmax) and gross ecosystem productivity (GEPmax), attaining rates that would be consistent with the presence of a strong terrestrial C sink in regions where these types of forest are common. These results support the idea that large-scale C cycle modeling activities would benefit from information on the age-class distribution and disturbance types within larger grid cells. Light use efficiency followed a pattern similar to that of NEPmax and GEPmax. Four of the five recently disturbed sites and all three of the peatland sites had low water use efficiencies.

The First Industrial Revolution

2020 ◽  
pp. 27-43
Author(s):  
Jonathan Scott
Keyword(s):  
East Asia ◽  
Technological Innovation ◽  
Large Scale ◽  
Industrial Revolution ◽  
Modern World ◽  
Factory Production

This chapter concerns the Industrial Revolution. The Industrial Revolution involved the transformation of organic economies by means of a complex of changes which gave birth to the modern world. In Europe, East Asia, and elsewhere those economies were agricultural. Thus the chapter discusses the replacement of an economy 80 per cent of the output of which might have been agricultural by another in which manufacturing became the dominant sector. This involved a transition in the scale of manufacturing from artisanal to large-scale workshop and then factory production. In Britain, that entailed technological innovation, but it would not have been possible in the first place without prior sustained changes in the rest of the economy and society.

scholarly journals Lengthening of summer season over the Northern Hemisphere under 1.5°C and 2.0°C global warming

2021 ◽  
Author(s):  
Bo-Joung Park ◽  
Seung-Ki Min ◽  
Evan Weller
Keyword(s):  
Global Warming ◽  
East Asia ◽  
Northern Hemisphere ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Late Summer ◽  
Industrial Condition ◽  
Summer Season ◽  
Hot Days

Abstract Summer season has lengthened substantially across Northern Hemisphere (NH) land over the past decades, which has been attributed to anthropogenic greenhouse gas increases. This study examines additional future changes in summer season onset and withdrawal under 1.5℃ and 2.0℃ global warming conditions using multiple atmospheric global climate model (AGCM) large-ensemble simulations from the Half a degree Additional warming, Prognosis and Projected Impacts (HAPPI) project. Five AGCMs provide more than 100 runs of 10-year length for three experiments: All-Hist (current decade: 2006-2015), Plus15, and Plus20 (1.5℃ and 2.0℃ above pre-industrial condition, respectively). Results show that with 1.5℃ and 2.0℃ warmer conditions summer season will become longer by a few days to weeks over entire NH lands, with slightly larger contributions by delay in withdrawal due to stronger warming in late summer. Stronger changes are observed more in middle latitudes than high latitudes and largest expansion (up to three weeks) is found over East Asia and the Mediterranean. Associated changes in summer-like day frequency is further analyzed focusing on the extended summer edges. The hot days occur more frequently in lower latitudes including East Asia, USA and Mediterranean, in accord with largest summer season lengthening. Further, difference between Plus15 and Plus20 indicates that summer season lengthening and associated increases in hot days can be reduced significantly if warming is limited to 1.5℃. Overall, similar results are obtained from CMIP5 coupled GCM simulations (based on RCP8.5 scenario experiments), suggesting a weak influence of air-sea coupling on summer season timing changes.

Circulation Features Associated with the Record-Breaking Rainfall over South China in June 2017

2018 ◽  
Vol 31 (18) ◽  
pp. 7209-7224 ◽  
Author(s):  
Jianqi Sun ◽  
Jing Ming ◽  
Mengqi Zhang ◽  
Shui Yu
Keyword(s):  
East Asia ◽  
South China ◽  
North Atlantic ◽  
Large Scale ◽  
Wave Train ◽  
Western Pacific Subtropical High ◽  
Early Summer ◽  
Intense Rainfall ◽  
Maritime Continent ◽  
Anomalous Anticyclone

In June 2017, south China suffered from intense rainfall that broke the record spanning the previous 70 years. In this study, the large-scale circulations associated with the south China June rainfall are analyzed. The results show that the anomalous Pacific–Japan (PJ) pattern is a direct influence on south China June rainfall or East Asian early summer rainfall. In addition, the Australian high was the strongest in June 2017 during the past 70 years, which can increase the equatorward flow to northern Australia and activate convection over the Maritime Continent. Enhanced convection over the Maritime Continent can further enhance local meridional circulation along East Asia, engendering downward motion over the tropical western North Pacific and enhancing the western Pacific subtropical high (WPSH) and upward motion over south China, which increases the rainfall therein. In addition, a strong wave train pattern associated with North Atlantic air–sea interaction was observed in June 2017 at Northern Hemispheric mid- to high latitudes; it originated from the North Atlantic and propagated eastward to East Asia, resulting in an anomalous anticyclone over the Mongolian–Baikal Lake region. This anomalous anticyclone produced strong northerly winds over East Asia that encountered the southerly associated with the WPSH over south China, thereby favoring intense rainfall over the region. Case studies of June 2017 and climate research based on data during 1979–2017 and 1948–2017 indicate that the extremities of the atmospheric circulation over south Europe and Australian high and their coupling with the PJ pattern could be responsible for the record-breaking south China rainfall in June 2017.

scholarly journals Quantifying pollution inflow and outflow over East Asia in spring with regional and global models

2010 ◽  
Vol 10 (9) ◽  
pp. 4221-4239 ◽  
Author(s):  
M. Lin ◽  
T. Holloway ◽  
G. R. Carmichael ◽  
A. M. Fiore
Keyword(s):  
Boundary Layer ◽  
Air Pollution ◽  
High Resolution ◽  
Boundary Conditions ◽  
East Asia ◽  
Large Scale ◽  
Regional Model ◽  
Global Model ◽  
Global Models ◽  
High Resolution Models

Abstract. Understanding the exchange processes between the atmospheric boundary layer and the free troposphere is crucial for estimating hemispheric transport of air pollution. Most studies of hemispheric air pollution transport have taken a large-scale perspective using global chemical transport models with fairly coarse spatial and temporal resolutions. In support of United Nations Task Force on Hemispheric Transport of Air Pollution (TF HTAP; www.htap.org), this study employs two high-resolution atmospheric chemistry models (WRF-Chem and CMAQ; 36×36 km) driven with chemical boundary conditions from a global model (MOZART; 1.9×1.9°) to examine the role of fine-scale transport and chemistry processes in controlling pollution export and import over the Asian continent in spring (March 2001). Our analysis indicates the importance of rapid venting through deep convection that develops along the leading edge of frontal system convergence bands, which are not adequately resolved in either of two global models compared with TRACE-P aircraft observations during a frontal event. Both regional model simulations and observations show that frontal outflows of CO, O3 and PAN can extend to the upper troposphere (6–9 km). Pollution plumes in the global MOZART model are typically diluted and insufficiently lofted to higher altitudes where they can undergo more efficient transport in stronger winds. We use sensitivity simulations that perturb chemical boundary conditions in the CMAQ regional model to estimate that the O3 production over East Asia (EA) driven by PAN decomposition contributes 20% of the spatial averaged total O3 response to European (EU) emission perturbations in March, and occasionally contributes approximately 50% of the total O3 response in subsiding plumes at mountain observatories (at approximately 2 km altitude). The response to decomposing PAN of EU origin is strongly affected by the O3 formation chemical regimes, which vary with the model chemical mechanism and NOx/VOC emissions. Our high-resolution models demonstrate a large spatial variability (by up to a factor of 6) in the response of local O3 to 20% reductions in EU anthropogenic O3 precursor emissions. The response in the highly populated Asian megacities is 40–50% lower in our high-resolution models than the global model, suggesting that the source-receptor relationships inferred from the global coarse-resolution models likely overestimate health impacts associated with intercontinental O3 transport. Our results highlight the important roles of rapid convective transport, orographic forcing, urban photochemistry and heterogeneous boundary layer processes in controlling intercontinental transport; these processes may not be well resolved in the large-scale models.

scholarly journals A Case Study of Subtropical Frontogenesis during a Blocking Event

2007 ◽  
Vol 135 (7) ◽  
pp. 2588-2609 ◽  
Author(s):  
George Tai-Jen Chen ◽  
Chung-Chieh Wang ◽  
An-Hsiang Wang
Keyword(s):  
Large Scale ◽  
Frontal Zone ◽  
Southern China ◽  
Sensible Heat Flux ◽  
Northern China ◽  
Sensible Heat ◽  
Surface Data ◽  
Sea Area ◽  
Blocking Event

Abstract During 8–14 June 2000, a 500-hPa blocking event occurred over Mongolia and northern China (near 45°N, 108°E), which was the only case over this region in June since 1981. As the block developed, the initially weak low-level mei-yu front over southern China evolved into a system with strong baroclinity and subsequently moved south. The frontal passage over Taiwan caused temperatures to drop by 10°C, the largest in June over two decades. Using gridded analyses, manually analyzed weather maps, and satellite and surface data, the present study investigates the evolution of this mei-yu front under the influence of the block. The 925-hPa frontogenetical function is computed and effects of different processes are discussed. As the blocking event developed, concurrent ridge–trough amplification in the lower–midtroposphere produced a reversed thermal pattern. The lower-tropospheric high moved southward, and large-scale confluence and deformation were enhanced between the northerly flow and the prefrontal southwesterly flow. The location of the block, to the west-southwest of the Okhotsk Sea area, allowed it to affect the front over southern China and caused it to penetrate inside 20°N, unusual for the month of June. The distribution of the frontogenetical function indicated that the mei-yu frontogenesis and the maintenance of the front were attributed to both deformation and convergence. These two processes together counteracted the strong frontolysis along the frontal zone from diabatic effects, caused by evaporative cooling of frontal precipitation on the warm side and stronger sensible heat transfer (and daytime heating over less cloudy areas) on the cold side of the front. When deformation, convergence, and diabatic effects were all combined, the net total frontogenesis peaked slightly ahead of the frontal zone, thus contributing to the southward propagation of the front in addition to the advection by postfrontal cold air in the present case. When the front moved into the South China Sea, the cross-frontal thermal gradient diminished rapidly, mainly due to the frontolytic effect from sensible heat flux over warm waters.

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