A rain tower and wind tunnel for studying the dispersal of plant pathogens by rain and wind

Abstract

The rain tower/wind tunnel complex at Rothamsted consists of a rain tower (height 11 m, cross-section 1 m2) linked to the upwind end of a wind tunnel (length 12 m, cross-section 1 m2), which may be operated in either an open or a closed configuration. At the top of the rain tower, water drops with diameters of 2.5 to 5 mm are produced by a drop generator, which can be fitted with different nozzles. Simulated rain with a drop diameter of 1 to 3 mm is produced at a rate of 8 to 12 mm h-1 by a rain generator with an area of 52 × 67 cm. The rain tower may be operated in conjunction with the wind tunnel in an open configuration. The windspeed can be decreased from a maximum of 8 m s-1 by decreasing the speed of the fan. The wind tunnel has its own internal lighting. When the wind tunnel is in a closed configuration, temperature and humidity can be controlled in the range 12 oC (62–80% r.h.) to 35 oC (22–50% r.h.). Data presented illustrate the use of this rain tower/wind tunnel complex to study dispersal of plant pathogen spores by rain-splash or wind.