Bremerhaven, July 2nd 2009. A new measurement system for the detection of whales is used for the first time on board of the research vessel Polarstern. Whales are usually difficult to spot. On the one hand, they spend the greater part of their life under water. On the other hand, only a small part of their body can be seen when they surface, and this can even hardly be distinguished from the surrounding water. Visual sightings by marine mammal observers are therefore usually based on observations of the spout, the condensing and quite warm breathing cloud. It rises, depending on the whale species and wind conditions, between one metre and ten metres over the water surface and remains visible for only a few seconds. A thermal imaging camera specifically optimized for this purpose now uses the heat of this spout. It is employed for the first time during the current expedition of RV Polarstern.
The underlying measurement method, infrared thermography, registers both at day and night the heat radiation originating from each body. It depicts it on a computer screen as a black and white picture, thus making it visible for humans: the brighter a spot, the warmer it is. The warm spout of a whale clearly stands out against the background of the cold North Atlantic or Antarctic waters.
Infrared thermography is already in use with great success, for example to examine the heat insulation of buildings. However, the ship-based detection of whales on sea presents new challenges: the camera must have "all-round visibility", it is subject to the constant movement of the ship and the spout is only briefly visible, possibly at a great distance. This poses high demands on the camera's optics: similar to animal photography, highest resolution telephoto lenses are necessary. When mounted to the ship, however, the camera would, due to the ship's motion, only point into the sky for much of the time.
A new thermal imager developed by Rheinmetall Defence Electronics,
|Contact: Dr. Olaf Boebel|
Helmholtz Association of German Research Centres