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| Titel |
Dispersion of the Nabro volcanic plume and its relation to the Asian summer monsoon |
| VerfasserIn |
T. D. Fairlie, J.-P. Vernier, M. Natarajan, K. M. Bedka |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 13 ; Nr. 14, no. 13 (2014-07-10), S.7045-7057 |
| Datensatznummer |
250118879
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| Publikation (Nr.) |
 copernicus.org/acp-14-7045-2014.pdf |
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| Zusammenfassung |
| We use nighttime measurements from the Cloud Aerosol Lidar and Infrared
Pathfinder Satellite Observation (CALIPSO) satellite, together with a
Lagrangian trajectory model, to study the initial dispersion of volcanic
aerosol from the eruption of Mt. Nabro (Ethiopia/Eritrea) in June 2011. The
Nabro eruption reached the upper troposphere and lower stratosphere (UTLS)
directly, and the plume was initially entrained by the flow surrounding the
Asian anticyclone, which prevails in the UTLS from the Mediterranean Sea to
East Asia during boreal summer. CALIPSO detected aerosol layers, with
optical properties consistent with sulfate, in the lower stratosphere above
the monsoon convective region in South and Southeast Asia within 10 days of
the eruption. We show that quasi-isentropic differential advection in the
vertically sheared flow surrounding the Asian anticyclone explains many of
these stratospheric aerosol layers. We use Meteosat-7 data to examine the
possible role of deep convection in the Asian monsoon in transporting
volcanic material to the lower stratosphere during this time, but find no
evidence that convection played a direct role, in contrast with claims made
in earlier studies. On longer timescales, we use CALIPSO data to illustrate
diabatic ascent of the Nabro aerosol in the lower stratosphere at rates of
~ 10 K per month for the first two months after the eruption,
falling to ~ 3 K per month after the Asian anticyclone
dissipates. Maps of stratospheric aerosol optical depth (AOD) show local
peaks of ~ 0.04–0.06 in July in the region of the Asian
anticyclone; we find associated estimates of radiative forcing small,
~ 5–10% of those reported for the eruption of Mt. Pinatubo in
1991. Additionally, we find no clear response in outgoing shortwave (SW)
flux due to the presence of Nabro aerosol viewed in the context of SW flux
variability as measured by CERES (Clouds and Earth Radiant Energy
System). |
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