T h e r m a l i m a g i n g : Thermal images were obtained
using an uncooled focal plane array infrared camera
(NEC TH7102 MX). The instrument operates in the waveband
between 8-14 μm. The detector array has a geometric
resolution of 1.58 m rad (320 x 240 pixels focal plane array
and a 29o x 22o field of view lens with a minimum focus
distance of 0.3 m). The thermal resolution is 0.06 oC and
accuracy of absolute temperature measurement less than
± 2 oC. Images were analysed using the Pic-Win-IRIS software
(ebs-GmbH, München).