This page last reviewed August 10, 2009

Description of SCOS97 3-D Ozone Images

The images display measured ozone concentrations at the surface and aloft. The scenes were generated for the SCOS97 modeling domain on an hourly basis starting at midnight on the first date in each sequence, and ending at midnight on the last date in each sequence. A typical scene includes 60-80 data points (when only ground stations are reporting) to 500-600 data points (multiple ozonesondes and aircraft). Color coding of the ozone measurements is non-linear (as shown on the scale in the upper right corner of each image): blue for ozone below 40 ppb, linearly transitioning through green to yellow at 90 ppb, linearly transitioning to red at 120 ppb and greater.

Topography color coding is black below mean sea level, blue for the ocean, green up to 1.5 km elevation, brown up to 3 km elevation, and white above this. This is arbitrary. The red lines are county boundaries, and are offset 0.5 km to the northeast (this offset will be eliminated in future updates). The images do not include air basin or district boundaries, as this appears rather busy for these scenes.

The camera was located approximately 300 km. south of the California/Mexico border. The camera had a 60° field of view, and "looked" at the center of the SCOS 97 domain. All of these parameters are controllable. Displayed altitude ranges from 0.2 km below sea level to 7 km above sea level, since some of the ozonesondes occasionally went as high as 6.5 km.

Diffuse lighting was set at 20%, and directional lighting intensity was varied with time of day from 100% at noon to 20% at midnight (to allow viewing night scenes). Directional lighting followed sun position during the day, and an assumed lunar position at night, so shadows appear on the topography to cue the viewer to the time of day. Without this diurnal lighting variation, scenes appear in constant illumination, and you can only tell time of day from the header caption. Times are PDT.

For the ozonesondes and aircraft, vertical red lines were run from each data point, down to the zero elevation plane, to aid in estimating the elevation and location of each data point. Without this aid, it is difficult to estimate elevation or location along an aircraft trajectory, for example.

Future Work

Future work will initially focus on incorporating remaining ozone measurements, specifically San Diego and US Navy aircraft data, LIDAR data (if feasible), and Northern Mexico ground station data. Additionally, alternate viewpoints for the images will be investigated, to better view data obscured by terrain or other data. We also plan to investigate displaying meteorological measurements.


The 3-D images were generated by Art Collins using IBM Data Explorer. Web access and design is by Don Johnson. Thanks go to both.


Comments and suggestions are welcome. Please e-mail them to the following:

John DaMassa, Manager
Control Strategy Modeling Section

Observed Ozone Images