Data of Volcanic Aerosol Forcing

 

Strong volcanic eruptions have a climate impact. Volcanologists measure the power of an eruption by the volcanic explosivity index VEI in order to scale and to compare the eruptions of different volcanoes. Aside the volume of erupted material also the plume height and frequency of eruption are considered. The scale is open-ended and starts from 0, for non-explosive eruptions. From a climatological point of view only the stratospheric mass loading is of interest since it resides long enough to alter the atmospheres radiation budget for months. Grieser and Schönwiese (1999) therefore introduced a climatologically corrected VEIc which is proportional to the logarithm of the estimated stratospheric mass loading.

 

Within the period from 1951 to 2000 5 volcanoes erupted with a climatologically corrected Volcanic Explosivity Index VEIc>5. These are summarized in Table 1.

 

Table 1: The 5 volcano eruptions with a climatologically corrected Volcanic Explosivity Index VEIc>5 within the period 1951 to 2000.

Name

Date

Country

VEIc

Agung

3/1963

Lesser Sunday Islands

5.9

Fernandina

6/1968

Galapagos

5.4

Fuego

10/1974

Guatemala

5.3

El Chichon

4/1982

Mexico

5.8

Pinatubo

6/1991

Philippines

6.1

 

 

Furthermore Grieser and Schönwiese (1999) applied a simple stratospheric transport model which takes into account the tropical pipe and a non-local transport scheme with seasonal dependency. This allows to calculate aerosol optical thickness for both hemispheres and tropical and outertropical regions.[volcanic aerosol optical thickness data]

 

A simple radiation transfer model is used in order to estimate the volcanic climate forcing. It is calibrated with respect to the Pinatubo eruption in 1991. Forcing anomalies are calculated. [volcanic forcing data]

 

Finally, a simple energy balance model (EBM) is driven with the volcanic forcing, leading to modelled hemispheric surface air temperature reactions. [sea surface temperature response data]

 

Reference:

 

Grieser, J. and C.-D. Schönwiese, 1999: Parameterization of spatio-temporal patterns of volcanic aerosol induced stratospheric optical depth and its climate radiative forcing. Atmósfera 12, 111-133.