Trans-Boundary Volcanic SO2 Detected over Pakistan from Satellite Observations during the Time Period 2004-2012

Palwasha Khattak,Muhammad Fahim Khokhar,Saud Ahmed Khan

doi:10.4209/aaqr.2013.12.0361

Abstract

This study emphasizes on the amount of trans-boundary Sulfur dioxide (SO_2) present in the atmosphere of Pakistan as a consequence of various global volcanic eruptions, by using satellite data. The data products of SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY), Ozone Monitoring Instrument (OMI) and Global Ozone Monitoring Experiment-2 (GOME-2) were used for the time period of 2004-2012. SO_2 columns retrieved with Differential Optical Absorption Spectroscopy (DOAS) technique were used to perform both spatial and temporal analyses. The Nabro volcano eruption during 2011 had caused high SO_2 columns over East Africa, Middle East and South Asian regions. Daily satellite observations were used to study SO_2 plume pathway during this event. Other significant volcanic eruptions and their effects on atmospheric composition of Pakistan are also discussed. Back trajectory analysis is also performed to track the origin of air masses enriched with SO_2 column densities detected over Pakistan. Maximum SO_2 column densities of 9.4 Dobson Units (DU) were measured over Pakistan caused by Dalafilla volcanic eruption during November 2008.

Highlights

Atmospheric sulfur dioxide (SO2) results from both natural and anthropogenic sources (Kettle and Andreae, 2000; Halmer et al, 2002; Vijay et al, 2004; Dentener et al, 2006; Lee et al, 2008)
This study has first time emphasized on the amount of trans-boundary SO2 pollution present in the atmosphere of Pakistan as a consequence of global and regional volcanic eruption by using satellite remote sensing data
Tor Zawar volcano located in Pakistan, erupted during January 2010 but no SO2 emissions were reported and detected via satellite observations

Summary

Introduction

Atmospheric sulfur dioxide (SO2) results from both natural and anthropogenic sources (Kettle and Andreae, 2000; Halmer et al, 2002; Vijay et al, 2004; Dentener et al, 2006; Lee et al, 2008). Volcanic eruptions are sporadic and major contributor, emitting 7.5– 13 Tg SO2 per year (Andres and Kasgnoc, 1998; Halmer et al, 2002). SO2 life time varies from few days to several weeks in the troposphere due to its reaction with hydroxyl (OH) and other oxidizing agents (Finlayson-Pitts and Pitts, 2000; Platt and Stutz, 2004) by several homogeneous and heterogeneous processes. In the lower stratosphere lifetime of SO2 exceeds from several weeks to 2 years (Eisinger and Burrows, 1998; Platt and Stutz, 2004). Tropospheric lifetime of SO2 allows it to travel larger distances before it is washed-out or transformed into sulfuric

Methods

Findings

Discussion

Conclusion