Impact of Tropical Volcanic Eruptions on Hadley Circulation Using a High-Resolution AGCM

Handle URI:
http://hdl.handle.net/10754/627516
Title:
Impact of Tropical Volcanic Eruptions on Hadley Circulation Using a High-Resolution AGCM
Authors:
Dogar, Muhammad Mubashar
Abstract:
The direct radiative effects of volcanic eruptions resulting in solar dimming, stratospheric warming, global surface cooling and reduction in rainfall are well documented. However, eruptions also cause indirect climatic impacts that are not well understood. For example, solar dimming induced by volcanic aerosols could cause changes in tropical Hadley circulation that in turn largely affect evaporation and precipitation patterns. Therefore, understanding the sensitivity of HC to volcanism is essential, as this circulation is directly related to precipitation changes in the tropics and with other large-scale circulations. Hence, to better understand the post-eruption sensitivity of HC and associated changes in the hydrologic cycle, simulations for the El Chichón and Pinatubo tropical eruptions were conducted using a high-resolution atmospheric model (HIRAM), effectively at 25 and 50 km grid spacing. The model simulated results are then compared with observational and reanalysis products. Both the model and observational analysis show posteruption weakening, shrinking and equatorward displacement of the updraft branch of HC caused by the equatorward shift of midlatitude jets and hemispheric land-sea thermal gradient. The Intertropical Convergence Zone (ITCZ) is tightly coupled to the rising branch of HC, hence, post-eruption weakening and equatorward displacement of HC cause weakening of ITCZ that adversely affects rainfall distribution in the monsoon-fed regions, especially the South Asian and African tropical rain-belt regions. The modelproduced post-eruption distribution of cloud contents suggests a southward shift of ITCZ. The HIRAM results are largely in agreement with the reanalysis, observations and previous studies indicating that this model performs reasonably well in reproducing the global and regional-scale dynamic changes caused by volcanic radiative forcing.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Earth Science and Engineering Program
Citation:
Dogar MM (2018) Impact of Tropical Volcanic Eruptions on Hadley Circulation Using a High-Resolution AGCM. Current Science 114: 1284. Available: http://dx.doi.org/10.18520/cs/v114/i06/1284-1294.
Publisher:
Current Science Association
Journal:
Current Science
Issue Date:
31-Mar-2018
DOI:
10.18520/cs/v114/i06/1284-1294
Type:
Article
ISSN:
0011-3891
Sponsors:
I thank Earth Science and Engineering Department, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia for providing computational facilities that were used to conduct model simulations. The observational and simulation results are available from the author upon request
Additional Links:
http://www.currentscience.ac.in/Volumes/114/06/1284.pdf
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Earth Science and Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.authorDogar, Muhammad Mubasharen
dc.date.accessioned2018-04-16T11:27:43Z-
dc.date.available2018-04-16T11:27:43Z-
dc.date.issued2018-03-31en
dc.identifier.citationDogar MM (2018) Impact of Tropical Volcanic Eruptions on Hadley Circulation Using a High-Resolution AGCM. Current Science 114: 1284. Available: http://dx.doi.org/10.18520/cs/v114/i06/1284-1294.en
dc.identifier.issn0011-3891en
dc.identifier.doi10.18520/cs/v114/i06/1284-1294en
dc.identifier.urihttp://hdl.handle.net/10754/627516-
dc.description.abstractThe direct radiative effects of volcanic eruptions resulting in solar dimming, stratospheric warming, global surface cooling and reduction in rainfall are well documented. However, eruptions also cause indirect climatic impacts that are not well understood. For example, solar dimming induced by volcanic aerosols could cause changes in tropical Hadley circulation that in turn largely affect evaporation and precipitation patterns. Therefore, understanding the sensitivity of HC to volcanism is essential, as this circulation is directly related to precipitation changes in the tropics and with other large-scale circulations. Hence, to better understand the post-eruption sensitivity of HC and associated changes in the hydrologic cycle, simulations for the El Chichón and Pinatubo tropical eruptions were conducted using a high-resolution atmospheric model (HIRAM), effectively at 25 and 50 km grid spacing. The model simulated results are then compared with observational and reanalysis products. Both the model and observational analysis show posteruption weakening, shrinking and equatorward displacement of the updraft branch of HC caused by the equatorward shift of midlatitude jets and hemispheric land-sea thermal gradient. The Intertropical Convergence Zone (ITCZ) is tightly coupled to the rising branch of HC, hence, post-eruption weakening and equatorward displacement of HC cause weakening of ITCZ that adversely affects rainfall distribution in the monsoon-fed regions, especially the South Asian and African tropical rain-belt regions. The modelproduced post-eruption distribution of cloud contents suggests a southward shift of ITCZ. The HIRAM results are largely in agreement with the reanalysis, observations and previous studies indicating that this model performs reasonably well in reproducing the global and regional-scale dynamic changes caused by volcanic radiative forcing.en
dc.description.sponsorshipI thank Earth Science and Engineering Department, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia for providing computational facilities that were used to conduct model simulations. The observational and simulation results are available from the author upon requesten
dc.publisherCurrent Science Associationen
dc.relation.urlhttp://www.currentscience.ac.in/Volumes/114/06/1284.pdfen
dc.rightsArchived with thanks to Current Scienceen
dc.subjectAtmospheric modelsen
dc.subjectJet streamsen
dc.subjectMonsoon circulation and ITCZen
dc.subjectTropical volcanic eruptionsen
dc.titleImpact of Tropical Volcanic Eruptions on Hadley Circulation Using a High-Resolution AGCMen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentEarth Science and Engineering Programen
dc.identifier.journalCurrent Scienceen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionGlobal Change Impact Studies Centre (GCISC), Ministry of Climate Change, Islamabad, , Pakistanen
kaust.authorDogar, Muhammad Mubasharen
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