Infrared heater arrays for warming ecosystem field plots

There is a need for methodology to warm open-field plots in order to study the likely effects of global warming on ecosystems in the future. Herein, we describe the devel-opment of arrays of more powerful and efficient infrared heaters with ceramic heating elements. By tilting the heaters at 451 from horizontal and combining six of them in a hexagonal array, good uniformity of warming was achieved across 3-m-diameter plots. Moreover, there do not appear to be obstacles (other than financial) to scaling to larger plots. The efficiency [gh (%); thermal radiation out per electrical energy in] of these heaters was higher than that of the heaters used in most previous infrared heater experiments and can be described by: gh5 101 25exp(0.17 u), where u is wind speed at 2m height (m s1). Graphs are presented to estimate operating costs from degrees of warming, two types of plant canopy, and site windiness. Four such arrays were deploye