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Simulating the relationship between influencing factors

To predict whether detection potential is above or below detection benchmarks for different equipment (including dogs and rats), we must understand the relationship between:

  • flux rate
  • target scent at surface level
  • the effects of weather and soil properties on movement of vapour through soil.

Defining the limits of detection will assist in understanding the optimal deployment of animal detector systems, and productivity and safety should also be improved.

In order to fully evaluate field performance results, simulation modelling should be performed, in order to estimate landmine chemical vapour and surface soil residue depending on the various daily and seasonal time periods. The simulation model will require appropriate input data, including:

  • mine source emission rates
  • soil-water-air partitioning
  • weather data.

Model improvements may depend on geographical location of the mine dog performance tests (eg inclusion of plants), on whether surface rainfall run-off is important, and whether vapour plume definition is desired (surface soil-atmosphere interface).

Since 1997, work supported by the United States Defence Advanced Research Projects Agency, the "Electronic Dog's Nose Project", investigated many aspects of environmental processes, including laboratory and field results of the transport of chemicals from buried landmines in soils. As part of this effort, the computer code T2TNT (Webb et al., 1999) was developed to simulate the chemical movement from landmines including the impact of environmental conditions such as wind, rain, and temperature.

The GICHD funded the application of T2TNT to landmine scenarios in Afghanistan and Bosnia where the effect of weather cycles on the chemical signatures has been documented, and expanded the project to involve additional T2TNT simulations. There are two separate tasks: the first is analysis of environmental factors for three different locations and the second is further evaluation of the predictive capability of T2NT. In addition, Sandia National Laboratories (Sweden) used the mine flux data for three different mine types.

The T2TNT model is being developed for use in support of humanitarian demining worldwide and users will require special training to understand data input requirements and how to interpret the results. Although not currently available for widespread use, it is intended for a broader users group. This would provide a double benefit, by increasing the analysis capability worldwide for chemical sensing of buried landmines, and providing feedback for any improvements needed.

Contact 

Guy Rhodes