author: Barron H. Henderson
date: 2021-09-23
This is a processor that generates Volcano SO2 from two types of OMI derived[1] databases:
- First, it can use the GEOS-Chem Volcano inputs to create CMAQ emissions.
- It can read the OMI Volcano eruption file directly.[1]
The GEOS-Chem processor follows the HEMCO extension. The HEMCO extension reads rc files that were originally developed for GEOS-5. These rc files use the latest and greatest Carn database[2] for both eruptive and degassing emissions. Where year-specific data is not available, degassing is provided using the last 5-years as a climatology and eruptions are omitted.
The OMI Volcano eruption file can also be read directly. This is useful because the GEOS-Chem inputs include climatalogical degassing, but can missing eruptions that have occured rescently.
- Download inputs
- MSVOLSO2L4 for eruptions file is available from https://so2.gsfc.nasa.gov/measures.html
- rc files from GEOS-Chem are available from https://ftp.as.harvard.edu/gcgrid/data/ExtData/HEMCO/VOLCANO/
- Edit run.cfg so that it points inputs and MCIP files for you domain.
- From the command line, run
python -m volcano2ioapi
- The emissions are assumed to be constant for each UTC day.
- Degassing and eruptions are emitted in the layer that contains the volcano altitude. This follows Itahashi et al. 2021 and allows for degassing at the volcano "surface" to be in a nonsurface cell. This is particularly useful for volcanos with peaks that are not representative of the grid cell surface level.
- The vertical allocation follows GEOS-5 by emitting in the top 1/3 of the plume cloud top height. I can imagine wanting to split some mass to the lower layers.
- To identify the vertical layers, the layer heights are read in from MCIP meteorology. The meteorology could be day-specific, but I used a monthly ensemble.
Currently, none is done. All emissions are stored as SO2_ERUPT or SO2_DEGAS.
Obviously, there are plenty of uncertainties. For example, the effective plume heights are specified for eruptive volcanoes – but the allocation is a simplistic. Also, at coarse resolutions its fine to put the whole volcano in one grid cell – but what if the volcano is near a 4km grid cell edge… So I expect finer scales to need empirical adjustment.
.
|-- README.md
| # This file.
|-- run.cfg
| # Example run configuration file
|-- volcano2cmaq
| # Definition of classes that read rc or text files
| # and allocate to vertical levels
|-- MakeVolcanoEmis.ipynb
| # Alternative driver for creating CMAQ Volcano emissions
|-- PlotVolcanoEmis.ipynb
| # Plotting Jupyter Notebook
|-- input
| `-- MSVOLSO2L4_20210621.txt
| # Eruptive volcanos
|-- mcip
| |-- 108NHEMI2
| `-- 27HI1
| # Each domain you want to run will need MCIP files that contain
| # a measure of height in meters. That will inclue HT from GRIDCRO2D
| # and ZF or ZH from METCRO3D
`-- output
|-- 108NHEMI2
`-- 27HI1
|-- so2_volcanic_emissions_Carns.%Y%m%d.27HI1.nc
| # Results include SO2_ERUPT and SO2_DEGAS
| # The user should confirm that SO2_ERUPT has non-zero
| # values on eruption days. If not, the values from
| # MSVOLSO2L4_%Y-%m-%d.27HI1.nc can be merged.
`-- MSVOLSO2L4_%Y-%m-%d.27HI1.nc
# Eruptive emissions read directly from the text file
# on OMI's website
[1] https://so2.gsfc.nasa.gov/measures.html [2] Carn, S. A., Yang, K., Prata, A. J., & Krotkov, N. A. (2015). Extending the long-term record of volcanic SO 2 emissions with the Ozone Mapping and Profiler Suite nadir mapper: OMPS volcanic SO2 measurements. Geophysical Research Letters, 42(3), 925–932. https://doi.org/10.1002/2014GL062437 [3] Itahashi, S., Mathur, R., Hogrefe, C., Napelenok, S. L., & Zhang, Y. (2021). Incorporation of volcanic SO<sub>2</sub> emissions in the Hemispheric CMAQ (H-CMAQ) version 5.2 modeling system and assessing their impacts on sulfate aerosol over the Northern Hemisphere. Geoscientific Model Development, 14(9), 5751–5768. https://doi.org/10.5194/gmd-14-5751-2021