Dispersion of volcanic aerosol from Mt. Nabro (2011) in the UTLS using CALIPSO observations and trajectory mapping
Abstract
We use cloud-filtered nighttime measurements of scattering ratio from CALIOP, and a Lagrangian trajectory model to study the dispersion of volcanic aerosol from the eruption of Mt. Nabro (Ethiopia/Eritrea) in June 2011. The CALIOP observations show that the volcanic plume reached the low stratosphere within 2 days of the main eruption, with the bulk of material between 380-420K potential temperature. Cloud top brightness temperatures from SEVIRI/Meteosat-9 indicate a direct injection of volcanic material into the low stratosphere from the eruption. AIRS/Aqua measurements show a significant enhancement of SO2 in the plume. Volume depolarization ratios from CALIOP indicate a mixture of ash and newly formed sulfate aerosol. Much of the plume was entrained initially into the Asian summer anticyclone, which extends from the Mediterranean to China. Detrainments from the anticyclone in early July followed two principal transport pathways: (1) westward across the Atlantic, in tropical easterlies, and (ii) eastward across the Northern Pacific in westerly winds, leading to dispersion of the plume throughout Northern mid-latitudes by August. We use our trajectory-mapped analyses of CALIOP data to interpret observations made from ground-based and airborne lidars, and to compute estimates of aerosol optical depth, top-of-atmosphere radiative forcing, and heating profile contributions, associated with the dispersed plume.ALIOP scattering ratio at 532nm, and volume depolarization cross-sections at 2239Z, 15 June 2011, show encounter with the volcanic plume near 42N,53 E in Central Asia, within days of the main eruption. White line shows the 380K isentropic surface. rajectory-mapped, scattering ratio from nighttime CALIPSO observations, valid 0 GMT, 15 July 2011, for the low stratosphere (380-420K). Warm colors illustrate the dispersal of the volcanic plume. Black contours show Montgomery Stream Function at 400K.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.A21K..08F
- Keywords:
-
- 0305 ATMOSPHERIC COMPOSITION AND STRUCTURE / Aerosols and particles;
- 0370 ATMOSPHERIC COMPOSITION AND STRUCTURE / Volcanic effects