Atmospheric temperature changes by volcanic eruptions: GPS radio occultation observations in the 2010 Icelandic and 2011 Chilean cases

摘要

Volcanic plumes modify atmospheric temperatures. Wang et al. (2009) reported localized temperature changes associated with the Mt Chaiten eruption in May 2008 using the deviation of GPS radio occultation temperature data from the NCEP global forecast system model. On 14 April 2010, a large scale eruption started under the glacier Eyjafjallajökull in Southern Iceland, and Puyehue-Cordón Caulle (Puyehue), in Chile, started eruption on 4 June, 2011. Here we study instantaneous and localized temperature changes with these two eruptions following the method of Wang et al. (2009). Post-eruption negative temperature anomalies at the 250 hPa plane were clearly observed in the Eyjafjallajökull eruption. In the Puyehue eruption, however, such anomalies were not so clear due possibly to insufficient accuracy of the forecast model. By comparing the temperature profiles in the downwind areas of the two eruptions, we found that significant temperature decreases occurred at ~ 10.5 and ~ 11.5 km altitude in the Eyjafjallajökull and the Puyehue cases, respectively. These results generally agree with Wang et al. (2009), but post-eruption temperature changes seem to be influenced by additional factors, e.g. volcanic explosivity and local climatology.