Eyjafjallajokull eruption

Model simulation

Model set-up

The version of the Unified EMEP model correspond to rv3_5_21 on FORECAST mode. The simulation was set up as chain of 6 day forecasts, driven by ECMWF meteorology (IFS, operational 00 UTC forecast). The simulation domain covers only [25W--35E]x[36N--75N] with a 0.2×0.2 resolution. The full extended model domain extends down to 31N, but the simulation goes only down to 36N.

Meteorology

The fields retrieved for the full extended forecast domain [25W--35E]x[31N--75N], from MARS include:

Levels (η=hibrid)	Resolution	Variables
srf.	0.2×0.2	sshf slhf msl 2t ewss nsss lsp cp ci sd swvl1
η91---η88	0.2×0.2	u v w t q cc
η87---η38	0.8×0.8	u v w t q cc

Emission set-up

Maximum plume height comes from London VAAC reports.

Emission rates of PM10 and PM2.5 interpreted from PDF and discussion with Ármann Höskuldsson (University of Iceland). Emission rates for the 14-16 are towards the higher end of the observed mean total ash emissions from the 14-16 and the 17-19 are from the low end of the observed mean total ash emissions from the 14-16 because emissions were reported to have decreased after the first three days. For the 20 it is lower because of reports that there is now less ash in the plume.

Emission rates of SO2 for the 15 are based on OMI SO2. The SO2 then decreases through the 18th consistent with reports of weaker plumes and OMI not observing new puffs clearly and then increases on the 19th. The SO2 values except for on the 15th are not based on total OMI observed SO2, rather they are intended to represent trends in the SO2 emissions.

Eruption emission parameters

PM10 [kg/s]	PM2.5 [kg/s]	SO2 [kg/s]	height [km]
2010-04-14	3E4	8.4E3	15	8
2010-04-15	3E4	8.4E3	46	7
2010-04-16	3E4	8.4E3	15	7
2010-04-17	6E3	1.7E3	10	7
2010-04-18	6E3	1.7E3	10	5
2010-04-19	6E3	1.7E3	20	5
2010-04-20---25	2E3	5.6E2	20	4

Implementation details

Emissions

Volcanic eruption emission are hard-coded into the model.

The eruption started on 2010-04-14 at 00 UTC and continues trough the simulation.

Emissions are treated as a vertical line source.

Emission rates for each day are assumed constant trough the column height.

Ash emissions are treated in the model as primary PM emissions.

In order to model only the volcanic plume only ash emissions are taken into account as primary PM emissions, i.e. all other primary PM emissions are neglected.

Primary fine PM (PPM25) emission rates are set accordingly to PM2.5 eruption parameters.

Primary coearse PM (PPMCO) emission rates are derived from PM10-PM2.5 eruption parameters.

Volcanic SO2 emissions are added to the standard model emissions.

Standard model emissions are set accordingly to the TNO-MACC-1 emission dataset.

Simulation

The simulations are run on titan (UiO) on 8×2 processors.

The driving bash and perl scripts at:

titan:~alvarov/Unify/run/cwf_ext-2010.sh

titan:~alvarov/Unify/run/modrun.rv3.CWF-EXT.pl

Source and meteorology files are located at:

titan:~alvarov/Unify/Unimod.rv3_5_21.CWF-EXT/

titan:/data3/metno/emep/Data/FORECAST/metdata/

2010/meteo-ext201004??_??.nc (EMEP Format)

2010_ECMWF/cwf-ext_*_f201004??.nc (retrieved from MARS)

The raw output and images is located at:

titan:~alvarov/CWF/output.rv3.CWF-EXT.2010

titan:~alvarov/CWF/output.rv3.CWF-EXT.2010/www/images

Results

The latest images (*.png) and animations (*.mpg) for each forecast day can be found here.

The YYYYMMDD.zip files contain all images for the forecast starting on YYYY-MM-DD, e.g. 20100414.zip contains all images for April 14th forecast.

Hourly images are named according to the following convention: name.png=var_lev_fsdate_date.png, where:

var is the variable name (e.g. ppm25 for fine volcanic particles);

lev is the level (e.g. tcol for total column);

fsdate is the forecast start date (in YYYYMMDD format);

date is the forecasted date and hour (in YYYYMMDDHH format);

fine, coarse and fine+coarse volcanic particles (var=ppm25,ppmco,ppm10 respectively) are shown in μg/m3 at c.a. 1 and 5 km of heigh (lev=1km,5km respectively);

SO2 (var=so2) tropospheric column (lev=so2) is shown in Dobson units (including non-volcanic emissions).

tropospheric column fine, coarse and fine+coarse volcanic particles (var_lev=ppm25_tcol,ppmco_tcol,ppm10_tcol respectively) are shown in μg/m2.

Animations for the hole period are named name.mpg=var_lev_fsdate.mpg

As emissions estimates improve past forecast will be re-run and the previous files updated. Re-run files include only one forecast day.

Additional resources

Satellite observations

GOME-2, SCIAMACHY & OMI SO2 column

MODIS AOD

Date	SO2 column	MODIS AOD
%F	%j	GOME-2	SCIAMACHY	OMI	Terra	Aqua
2010-04-14	104	zip	ftp	ftp	ftp
2010-04-15	105	zip	ftp	ftp	ftp
2010-04-16	106	zip	ftp	ftp	ftp
2010-04-17	107	zip	ftp	ftp	ftp
2010-04-18	108	zip	ftp	ftp	ftp
2010-04-19	109	zip	ftp	ftp	ftp
2010-04-20	110	zip	ftp
2010-04-21	111	zip	ftp

Other model simulations

SNAP Dispersion

MACC SO2 column

EURAD PM10