An Analysis of Air-Soil Temperature Differences at Five Locations: Application to Passive Standoff Chemical Detection


  1. Turcotte, C.S.
  2. Thériault, J-M.
Corporate Authors
Defence R&D Canada - Valcartier, Valcartier QUE (CAN)
For a passive spectral sensor such as CATSI (Compact ATmospheric Sounding Interferometer), the temperature difference ΔT) that exists between a chemical cloud and the background scene is of prime importance because it is linked to the radiative contrast of the target. The larger ∆T, the better the radiative contrast and the more accurate is the detection and identification, of the cloud. The purpose of this memorandum is to establish statistics on realistic air-soil temperature differences to be used to estimate the detection performance of CATSItype sensors in a variety of scenarios and environments. To this end, an analysis of the air-soil temperature differences is presented for five locations around the world; namely, 1- Sanborn Field, Boone County, Missouri, USA, 2- Novelty, Knox County, Missouri, USA, 3- Macquarie University, Sydney, Australia, 4- Murdoch University, Perth, Australia, and 5- Bylot Island, Nunavut, Canada. The results of the analysis indicate that the statistics of the air-soil temperature differences are similar from one location to another. The average statistics over the five locations show a mean air-soil temperature difference of 3.5 °C and a median of 2.8 °C. An air-soil temperature difference of less than one degree Celsius occurs less than 14% of the time on the average. This suggests that, on average, air-soil temperature contrasts should yield good detection probabilities 86% of the time.

Il y a un résumé en français ici.

Passive Standoff Detection;Air temperature;Soil temperature;Air-soil temperature difference;Radiative contrast;Passive Standoff Chemical Detection;CATSI (Compact ATmospheric Sounding Interferometer)
Report Number
DRDC-VALCARTIER-TM-2004-127 — Technical Memorandum
Date of publication
01 Sep 2004
Number of Pages

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