Analysis of Aerosol type and Fine- and Coarse-mode Aerosol Direct Radiative Forcing over Regions in East and Southeast Asia Based on AERONET Version 3 Data

AbstractAerosol chemical components such as black carbon (BC) and brown carbon (BrC) regulate aerosol optical properties, which in turn drive the atmospheric radiative forcing estimations due to aerosols. In this study, we used the long-term measurements from AERONET (Aerosol Robotic Network) to better understand the aerosol types and composition with respect to their seasonal and spatial variabilities in peninsular Southeast Asia (PSEA, here defined as Vietnam, Cambodia, Thailand, Laos, and Myanmar). Two methods (i.e., aerosol type cluster and aerosol component retrieval) were applied to determine the aerosol type and chemical composition during the biomass-burning (BB) season. AERONET sites in northern PSEA showed a higher AOD (aerosol optical depth) compared to that of southern PSEA. Differences in land use pattern, geographic location, and weather regime caused much of the aerosol variability over PSEA. Lower single-scattering albedo (SSA) and higher fine-mode fraction (FMF) values were observed in February and March, suggesting the predominance of BB type aerosols with finer and stronger absorbing particles during the dry season. However, we also found that the peak BB month (i.e., March) in northern PSEA may not coincide with the lowest SSA once dust particles have mixed with the other aerosols. Furthermore, we investigated two severe BB events in March of 2014 and 2015, revealing a significant BrC fraction during BB event days. On high AOD days, although the BC fraction was high, the BrC fraction remained low due to lack of aerosol aging. This study highlights the dominance of carbonaceous aerosols in the PSEA atmosphere during the BB season, while also revealing that transported dust particles and BrC aerosol aging may introduce uncertainties into the aerosol radiative forcing calculation.

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Book Reviews

Research in Language ◽

10.2478/v10015-007-0013-3 ◽

2007 ◽

Vol 5 ◽

pp. 251-292

Author(s):

Tor A. Åfarli ◽

Jarosław Jakielaszek ◽

Iwona Witczak-Plisiecka ◽

Wiktor Pskit ◽

Jolanta Szpyra-Kozłowska ◽

...

Keyword(s):

New York ◽

Southeast Asia ◽

English Language ◽

Oxford University ◽

East And Southeast Asia ◽

Adverbial Modification ◽

Secondary Predication ◽

Oxford University Press

Nikolaus P. Himmelmann, Eva F. Schultze-Berndt (eds), Secondary Predication and Adverbial Modification: The Typology of Depictives, Oxford: Oxford University Press, 2005. xxv + 448 pages Edward L. Keenan, Edward P. Stabler, Bare Grammar: Lectures on Linguistic Invariants. Stanford: CSLI Publications, 2003. 192 pp. Siobhan Chapman, Thinking about Language. Theories of English. Houndsmills and New York: Palgrave Macmillan, 2006. X + 174 pages. pb (Series: Perspectives on the English Language) Judith Rodby, W. Ross Winterowd, The Uses of Grammar, Oxford: Oxford & New York: Oxford University Press, 2005. xiv + 274 pp. Laura J. Downing, Alan T. Hall and Renate Raffelsiefen (eds), Paradigms in Phonological Theory. Oxford: Oxford University Press, 2005. 349 pages. Max W. Wheeler, The Phonology of Catalan. (The Phonology of the World’s Languages). Oxford: Oxford University Press, 2005. XI + 387 pp. Jan-Olof Svantesson, Anna Tsendina, Anastasia Karlson, and Vivan Franzén, The Phonology of Mongolian. Oxford: Oxford University Press, 2005. Pp. xix + 314. Cliff Goddard, The Languages of East and Southeast Asia. An Introduction. Oxford: Oxford University Press, 2005. pp. xvi + 315.

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Climate Change Mitigation Policy in East and Southeast Asia and Business Opportunities of Japanese Stakeholder in the Region

JAPAN TAPPI JOURNAL ◽

10.2524/jtappij.67.1396 ◽

2013 ◽

Vol 67 (12) ◽

pp. 1396-1401

Author(s):

Yasuhiro Kasuya

Keyword(s):

Climate Change ◽

Southeast Asia ◽

Climate Change Mitigation ◽

Mitigation Policy ◽

Business Opportunities ◽

Climate Change Mitigation Policy ◽

East And Southeast Asia ◽

Change Mitigation

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Shifting the Focus to East and Southeast Asia: A Critical Review of Regional Game Research

Fudan Journal of the Humanities and Social Sciences ◽

10.1007/s40647-021-00317-7 ◽

2021 ◽

Vol 14 (2) ◽

pp. 173-196

Author(s):

Phan Quang Anh

Keyword(s):

Southeast Asia ◽

Critical Review ◽

East And Southeast Asia

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Constitutions, Crisis, and Regime Change: Perspectives on East and Southeast Asia

Constitutions in Times of Financial Crisis ◽

10.1017/9781108679404.015 ◽

2019 ◽

pp. 305-326

Author(s):

Björn Dressel

Keyword(s):

Southeast Asia ◽

Regime Change ◽

East And Southeast Asia

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Estimates of direct radiative forcing due to aerosols from the MERRA-2 reanalysis over the Amazon region

10.5194/acp-2018-355 ◽

2018 ◽

Cited By ~ 1

Author(s):

Brunna Penna ◽

Dirceu Herdies ◽

Simone Costa

Keyword(s):

Radiative Forcing ◽

Reanalysis Data ◽

Amazon Region ◽

Reference State ◽

Aerosol Radiative Forcing ◽

Aerosol Loading ◽

Direct Radiative Forcing ◽

Direct Forcing ◽

The Difference ◽

Natural Aerosols

Abstract. Sixteen years of analysis of clear-sky direct aerosol radiative forcing is presented for the Amazon region, with calculations of AERONET network, MODIS sensor and MERRA-2 reanalysis data. The results showed that MERRA-2 reanalysis is an excellent tool for calculating and providing the spatial distribution of aerosol direct radiative forcing. In addition, the difference between considering the reference state of the atmosphere without aerosol loading and with natural aerosol to obtain the aerosol direct radiative forcing is discussed. During the dry season, the monthly average direct forcing at the top of atmosphere varied from −9.60 to −4.20 Wm−2, and at the surface, it varied from −29.81 to −9.24 Wm−2, according to MERRA-2 reanalysis data and the reference state of atmosphere without aerosol loading. Already with the state of reference being the natural aerosols, the average direct forcing at the top of atmosphere varied from −5.15 to −1.18 Wm−2, and at the surface, it varied from −21.28 to −5.25 Wm−2; this difference was associated with the absorption of aerosols.

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Contribution of anthropogenic aerosols in direct radiative forcing and atmospheric heating rate over Delhi in the Indo-Gangetic Basin

Environmental Science and Pollution Research ◽

10.1007/s11356-011-0633-y ◽

2011 ◽

Vol 19 (4) ◽

pp. 1144-1158 ◽

Cited By ~ 59

Author(s):

Atul K. Srivastava ◽

Sachchidanand Singh ◽

S. Tiwari ◽

D. S. Bisht

Keyword(s):

Heating Rate ◽

Radiative Forcing ◽

Anthropogenic Aerosols ◽

Atmospheric Heating ◽

Direct Radiative Forcing

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Impact of Desert Dust Radiative Forcing on Sahel Precipitation: Relative Importance of Dust Compared to Sea Surface Temperature Variations, Vegetation Changes, and Greenhouse Gas Warming

Journal of Climate ◽

10.1175/jcli4056.1 ◽

2007 ◽

Vol 20 (8) ◽

pp. 1445-1467 ◽

Cited By ~ 234

Author(s):

Masaru Yoshioka ◽

Natalie M. Mahowald ◽

Andrew J. Conley ◽

William D. Collins ◽

David W. Fillmore ◽

...

Keyword(s):

Surface Temperature ◽

Sea Surface Temperature ◽

North Africa ◽

Radiative Forcing ◽

Sea Surface ◽

Desert Dust ◽

Direct Radiative Forcing ◽

Sahel Region ◽

Precipitation Reduction ◽

Sahel Precipitation

Abstract The role of direct radiative forcing of desert dust aerosol in the change from wet to dry climate observed in the African Sahel region in the last half of the twentieth century is investigated using simulations with an atmospheric general circulation model. The model simulations are conducted either forced by the observed sea surface temperature (SST) or coupled with the interactive SST using the Slab Ocean Model (SOM). The simulation model uses dust that is less absorbing in the solar wavelengths and has larger particle sizes than other simulation studies. As a result, simulations show less shortwave absorption within the atmosphere and larger longwave radiative forcing by dust. Simulations using SOM show reduced precipitation over the intertropical convergence zone (ITCZ) including the Sahel region and increased precipitation south of the ITCZ when dust radiative forcing is included. In SST-forced simulations, on the other hand, significant precipitation changes are restricted to over North Africa. These changes are considered to be due to the cooling of global tropical oceans as well as the cooling of the troposphere over North Africa in response to dust radiative forcing. The model simulation of dust cannot capture the magnitude of the observed increase of desert dust when allowing dust to respond to changes in simulated climate, even including changes in vegetation, similar to previous studies. If the model is forced to capture observed changes in desert dust, the direct radiative forcing by the increase of North African dust can explain up to 30% of the observed precipitation reduction in the Sahel between wet and dry periods. A large part of this effect comes through atmospheric forcing of dust, and dust forcing on the Atlantic Ocean SST appears to have a smaller impact. The changes in the North and South Atlantic SSTs may account for up to 50% of the Sahel precipitation reduction. Vegetation loss in the Sahel region may explain about 10% of the observed drying, but this effect is statistically insignificant because of the small number of years in the simulation. Greenhouse gas warming seems to have an impact to increase Sahel precipitation that is opposite to the observed change. Although the estimated values of impacts are likely to be model dependent, analyses suggest the importance of direct radiative forcing of dust and feedbacks in modulating Sahel precipitation.

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