Easy Volcanic Aerosol (EVA) version 1: users guide Structure The EVA package is composed of: 1. The mo_EVA.f90 FORTRAN module: this holds all the subroutines used to calculate volcanic forcing 2. Three input files in netcdf format: a. EVA parameter set, specifying the values to be used for the parameterizations in the mo_EVA routines b.An eruption history file, specifying the date , location, stratospheric sulfur injection (in Tg S) and, optionally, the hemispheric asymmetry factor to be applied to each eruption. c. A lookup table, containing the scaling factors to convert EXT550 and reff to wavelength dependent EXT, SSA and ASY based on Mie Theory. 3. A FORTRAN main file to build a sulfate file specifying the timeseries of sulfate in the equatorial, NH and SH regions based on the box model transport scheme. 4. A FORTRAN main file to build aerosol property (or forcing) files from the sulfate timeseries. 5. A netcdf file containing specifications of the grids to be used in the output of EVA, ie., latitude, and wavelength. Compiling The FORTRAN routines all make use of the NETCDF fortran library, and so need to be linked to the library upon compilation. This can be achieved either by specifying the path to the netCDF intallation upon compilation: >> gcc -c mo_EVA.f90 -I $(NETCDF)/include or by first creating a symbolic link to the netcdf.mod file: >> ln -s $(NETCDF)/include/netcdf.mod . >> gcc c mo_EVA.f90 where, in both cases, $(NETCDF) refers to the directory of the netcdf installation on your system. Creating executables from the main programs requires linking to the mo_EVA.o module, and the netcdf libraries, e.g., >> gcc -o eva_build_sulfate_file eva_build_sulfate_file.f90 mo_EVA.o -L$(NETCDF)/lib lnetcdf with careful attention to the L and l flags required on your system. Running Step 1: build sulfate file The script eva_build_sulfate_file.f90 reads the eruption history file, and based on the parameter settings in EVAv1_parameter_set_v1.0.nc, builds a timeseries of effective sulfate mass*, saved in file eva_sulfate_timeseries.nc. * Effective sulfate mass should not necessarily be interpreted as being an accurate estimate of the real mass of sulfate aerosol for eruptions - please see discussion in the EVA paper. Once compiled, simply run the script: >> ./eva_build_sulfate_file Step 2: build forcing files The script eva_build_forcing_files.f90 builds yearly volcanic aerosol forcing files, with aerosol optical properties as a function of time, latitude, height and wavelength. Once the sulfate file is produced via step 1, and eva_build_forcing_files.f90 is compiled, simply run the script: >> ./eva_build_forcing_files As a default, this script produces forcing files for the years (YYYY) 1991 through 1995, as eva_forcing_echam_T63_sw_YYYY.nc. Modifications New input files Any of the input files can be readily swapped for alternative files, by changing the filenames given in the mo_EVA.f90 module and recompiling the module. This can be done to change the source of eruption histories, change the parameter setting of EVA, or change the Mie lookup tables. Care must be taken that the variable names and dimensions of the new input files are identical to those of the default input files. For different model set ups Modifying the output of EVA to different model specifications is possible by supplying an alternate grid file in the running of the eva_build_forcing_files routine. Care must be taken that the variables in the new grid file have the same names and dimensions as the default grid files (based on the ECHAM model specifications).