Lifetimes and timescales of tropospheric ozone: Ozone emission experiments

The lifetime of tropospheric O3 is difficult to quantify because we model O3 as a secondary pollutant, without direct emissions.  For other reactive greenhouse gases like CH4 and N2O, we readily model lifetimes and timescales that include chemical feedbacks based on direct emissions.  Here, we devise a set of artificial experiments with a chemistry-transport model where O3 is directly emitted into the atmosphere at a quantified rate.  We create three primary emission patterns for O3, mimicking secondary production by surface industrial pollution, that by aviation, and primary injection through stratosphere-troposphere exchange (STE).  The perturbation lifetimes for these O3 sources includes chemical feedbacks and varies from 6 to 27 days depending on source location and season.  Previous studies derived lifetimes around 24 days estimated from the mean odd-oxygen loss frequency.  The timescales for decay of excess O3 varies from 10–20 days in NH summer to 30–40 days in NH winter.  For ea..., Here we present the results from the UC Irvine chemistry-transport model (UCI CTM) used in the study of direct, primary ozone emissions.  There are 16 *.nc data files that provide a 3-D (every modeled grid cell, 320x160x57) snapshot of O3 or other key variables (air mass, e90(tropopause tracer), T and, surface pressure (2D only, 320x160).  The netcdf variables are 4-D, being sampled every 5 days for 5 years (320x160x57x365), for 4 years (320x160x57x292), or for 6 months (320x160x57x36). The 17th *.nc file gives the relative differences (RD) for the trace chemical species between the control run (CTRL) and the aviation direct-O3 emissions (EO3A) on July 1. 
The direct O3 emission case shorthand is:

EO3A = uses aviation NOx pattern for O3 emissions
EO3B = not direct O3 emissions, but a doubling of aviation NOx
EO3S = surface pollution pattern (NH Asia)
EO3T = stratosphere-troposphere exchange pattern
EO3U = revised stratosphere-troposphere exchange pattern

The Matlab scripts that read, ..., , # Lifetimes and timescales of tropospheric ozone: Ozone emission experiments

README for Elementa paper
17 netcdf files with UCI CTM output,

Each has one primary variable as noted,except that EO3_EO3A_1Jul2003.nc has Relative Differences for all species as explained below.

EO3_CTRL_prs.nc          43,391,995

EO3_CTRL_tem.nc       2,311,030,348

EO3_CTRL_ozo.nc       2,955,392,239

EO3_CTRL_e90.nc       3,051,450,892

EO3_CTRL_air.nc       1,519,051,040

EO3_EO3A_ozo.nc       2,364,511,906

EO3_EO3B_ozo.nc       2,364,326,446

EO3_EO3S_ozo.nc       2,364,489,251

EO3_EO3T_ozo.nc       2,364,599,147

EO3_EO3U_ozo.nc       2,364,330,292

EO3_EO3Td2_ozo.nc       291,719,936

EO3_EO3Td1_ozo.nc       291,582,443

EO3_EO3Sd2_ozo.nc       291,704,163

EO3_EO3Sd1_ozo.nc       291,576,627

EO3_EO3Ad2_ozo.nc       291,712,609

EO3_EO3Ad1_ozo.nc       291,582,195

EO3_EO3A_1Jul2003.nc      5,072,744

 

Source: G:\\...\\**EO3_CTRL_ozo.nc**

Format:  netcdf4

Dimensions:

           Lngs = 320

...