Hi Dr. Napelenok et al.,
I enjoyed the 10/8/2019 CMAQv5.3 webinar, Dr. Napelenok mentioned “sum of target species concentrations in ISAM should be very close to the concentration of this species from basic CMAQ output”. I then tested CMAQv5.3 ISAM with benchmark
TAG CLASSES |SULFATE, OZONE !!! The following are source definition text blocks in the format: !!! TAG NAME |Three character text string !!! REGION(S) |Keyword EVERYWHERE or variable names from the region file (multiple regions need to be comma delimited) !!! FILENAME(S) |Emissions labels (multiple labels need to be comma delimited) TAG NAME |GR1 REGION(S) |EVERYWHERE EMIS STREAM(S) |GRIDDED_EMIS ENDLIST eof
I then summed up O3_OTHER O3_ICON O3_BCON O3_GR1 and compared the data with O3 from original CMAQv5.3 output. scatter plot and domain average (total_O3_ISAM - O3_orig) look fine
However, I saw some large differences in certain grid-cells
absolute difference (up to 16 ppb in some grids)
Are these large differences normal for CMAQv5.3 ISAM? BTW, I’ve checked my benchmark run with reference data without ISAM, and even in the two-weeks simulation the difference < 0.5%.