An Improved Open-Top Chamber with Solar-Heated Double Funnels That Can Adapt to All Wind Directions for Simulating Future Global Warming Conditions in Rice Paddy Fields

Abstract

An Open-Top Chamber with Solar-heated Double Funnels (OTC-SDF2) that uses solar energy as a heating source was developed in this study. Two air entry/exit funnels were connected to the OTC via flat tunnels through which air was warmed by solar radiation. The new apparatus increased the air temperature by approximately 1°C throughout the chamber when more than half the energy of full sunlight was supplied. Although air flow occurs in only two directions, a nearly constant temperature increase was observed for each wind direction. This increase in temperature was stable for 1 m ˉs to 4 m ˉs wind speeds in every direction. This degree of warming may be adequate for screening high-temperature tolerant plants from medium to weak cultivars. The OTC-SDF2 has the potential to provide moderately high-temperature treatments for screening various cultivars/strains and may be used to evaluate easy, low-cost cropping methods associated with high-temperature stresses.