CATS Technological Hazards

CATS Chemical Weapon Scenario

Example Scenario Discussion

Example of a Chemical Weapon effects simulation performed with CATS' Hazards Prediction and Assessment Capability (HPAC) utility

HPAC supports a general hazard assessment utility for NBC materials released from NBC weapons or NBC materials released from production or storage facilities.
HPAC provides a capability for modeling winds over complex terrain and for forecasting weather, which is required for accurate hazard assessments in some locations and situations.
HPAC includes the SCIPUFF (Second-order Closure Integrated Puff) model for turublent transport, providing an efficient and accurate prediction for many types of hazard scenarios.
HPAC results are imported into CATS, overlaid upon detailed maps, and used for determining population at risk, infrastructure, casualties, and critical facilities affected.
HPAC is easily launched from within CATS:

Inputs

Definition of hazardous incident or source is created from within HPAC. The type of chemical agent, its delivery system, location and incident time are chosen by the user within the HPAC architecture. In this case, the example is of a Chemical Weapon Airspray attack near San Diego.
The user selects the weather data and inputs it to the model. Weather data includes quantities such as precipitation, wind speed and wind direction (in this case, provided in a wind grid format covering a user-defined area, i.e., Southern California), cloud cover, etc. The example shown is for a clear, temperate day, with wind data from October 29, 1998.
HPAC also selects as input the Digital Terrain Elevation Data (DTED) appropriate to the region of interest, especially important for mountainous Southern California terrain, in this example.
The user selects all these data by using simple GUIs similar to that shown below:

Outputs

Outputs include various types of color-coded "footprints" that are overlaid upon georeferenced maps.
Footprints such as agent dosage, agent concentration, probabilities of mortality, incapacitation, visual impairment, and symptom threshold, may be displayed.

The example below shows a footprint for lethal, incapacitating, and symptom threshold onset concentrations of the chemical agent. Displayed are probabilities (shown as color-coded contour areas) of:

LCT50 (meaning that persons in this area have a 50% chance of dying due to the chemical concentration present),
ICT50 (50% chance of being incapacitated),
ICT5 (5% chance of being incapacitated), and
Symptom-onset threshold.

Consequences Assessment

For CATS Technological Hazards scenarios, consequences assessment refers to determination of population at risk, infrastructure, casualties, and critical facilities lying within the extent of the hazard plume.

Population at risk refers to the total population lying within each of the plume contours. (The population data is provided with CATS and is 1990 Census Data.) This utility provides a quick and easy way to determine the total number of persons who might be in harm's way. For the example shown above, the user may determine the population at risk in each of the plume contours LCT50, ICT50, ICT5, and Symptom Threshold. The output is provided in a text report and is grouped by county (here, the only county affected is San Diego County):

Affected infrastructure is also provided in a text report, detailing numbers of infrastructure (whose types are selected by the user) lying within footprint areas. This example displays numbers of airports, helicopter pads, TV/Radio networks, water supply stations, and wholesale groceries, lying within LCT50, ICT50, ICT5, and Symptom Threshold plume areas. Many more types of infrastructures (approximately 60 total) are available for examination.

Casualties are also provided in a text report, displaying numbers of persons (1990 Census Data) projected to suffer mortality, incapacitation, visual impairment, and experience symptom threshold. The casualty determination utility is one of the most powerful consequences assessment utilities in CATS, and uses state-of-the-art computer codes for determining deaths and injuries from a variety of NBC agents. Casualties are modeled to occur to healthy persons in young adulthood.

The first step in performing a casualty calculation is to display and select one of these four themes in order to perform the calculation. (Casualties can only be determined with one of these four themes, in contrast to population at risk, which can be determined with any theme.) The example shown below is of a symptom threshold footprint display.

Next, CATS determines casualties for the San Diego Chemical Weapon Attack example. The casualty determination utility provides projected casualties for all four types of maladies, not just symptom threshold, even though symptom threshold was specifically chosen for the calculation. The output is provided in the form of a text report.

[The user can immediately compare the threshold numbers in the report with the threshold contours shown above and note that 168,386 persons within the entire area encompassed by these contours are projected to experience such symptoms. However, the numbers for mortality, for example, come from the mortality contours which are not shown in the picture above, but which the user can easily display by simply turning on the mortality theme.]

Critical facilities (such as hospitals, for example) are shown as map data, and their availability (and possible need to evacuate) in the aftermath of an attack is determined by their proximity to the hazard plume. The figure below displays the hazard plume and nearby San Diego area hospitals. In this case, only one hospital is in the path of the hazard. The user can click on this hospital's icon to produce its vital data: Phone Number, Hospital Name, Address, Zip Code, etc.

CATS Example Scenarios