A supersonic pan-evaporimeter was developed for performing dynamic analysis of evaporative demand in a greenhouse. The pan-evaporimeter comprises two parts: a small-sized cylindrical container (a diameter of 27 cm, a height of 15 cm) filled with water and a supersonic water-level detector. The pan evaporation rate (Epan) can be evaluated for an arbitrary time interval on the basis of the decrease in the water level due to evaporation from the pan-evaporimeter. The performance and validity of the pan-evaporimeter were examined by analyzing the characteristics of Epanon an hourly basis and its relation with the solar radiation, air temperature and humidity, wind speed, in addition, the transpiration rate of a tomato plant (Tr) in a greenhouse. A positive linear relationship was clearly obtained between the hourly Epanand the environmental elements, and then sensitivity of Epanto the environmental elements was revealed. Furthermore, a good correlation was found between the Epanand the Tr on hourly basis for one day. These results suggest that the developed pan-evaporimeter is a useful tool for analyzing the dynamics of evaporative demand and for estimating the transpiration rate in a greenhouse.
All Science Journal Classification (ASJC) codes
- Agronomy and Crop Science
- Atmospheric Science