Terra temperature, RH, leaf wetness combisensor 8. Skye SWD sensor 10. Global water Electronic - portable or low cost 1. Spectrum Scientific 2. More recently, types based on emerging technologies have been suggested as replacements.
Mechanical sensors measure a change in sensor length, size or weight caused by moisture deposition.
Disadvantages of mechanical sensors are that they are not readily compatible with modern, electronic digital weather station technology. The most common method of measurement of SWD is with an electronic grid. Electronic sensors measure surface water deposition by a change in sensor resistance or capacitance. In contrast, Armstrong et al. Griffioen et al.