We present a sensor for gas detection utilising an integrating sphere and interband cascade laser tunable diode absorption spectroscopy (TDLAS). Measurements were made of the methane line at 3313 nm using with effective pathlength 70.1 cm. Gas concentrations estimated from normalised spectra fitting to 7 lines within scan. Testing showed that measurements linear in synthetic air range 0–50 ppm....

Different sunfleck characteristics, length and number of sunflecks per metre and sunfleck fractional area, were measured at different depths inside willow (Salix viminalis) canopy. All these characteristics depend on the pathlength of the direct solar radiation beam into the canopy, τ=L/sin h, where L is the downward cumulative leaf area index and h is the solar elevation. The mean sunfleck len...