Infrared heater arrays for warming ecosystem field plots

	Infrared heater arrays for warming ecosystem field plots
	Kimball, Bruce A.1; Conley, Matthew M.1; Wang, Shiping 2; Lin, Xingwu 2; Luo, Caiyun 2; Morgan, Jack 3; Smith, David 3
刊名	global change biology
	2008-02-01
卷号	14 期号:2 页码:309-320
关键词	canopy temperature climate change ecosystems GIS global change global warming infrared heater rangeland thermal radiation wind speed
合作状况	其它
中文摘要	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 development of arrays of more powerful and efficient infrared heaters with ceramic heating elements. by tilting the heaters at 45 degrees 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 [eta(h) (%); 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: eta(h) = 10 + 25exp(-0.17 u), where u is wind speed at 2 m height (m s(-1)). graphs are presented to estimate operating costs from degrees of warming, two types of plant canopy, and site windiness. four such arrays were deployed over plots of grass at haibei, qinghai, china and another at cheyenne, wyoming, usa, along with corresponding reference plots with dummy heaters. proportional integral derivative systems with infrared thermometers to sense canopy temperatures of the heated and reference plots were used to control the heater outputs. over month-long periods at both sites, about 75% of canopy temperature observations were within 0.5 degrees c of the set-point temperature differences between heated and reference plots. electrical power consumption per 3-m-diameter plot averaged 58 and 80 kw h day(-1) for haibei and cheyenne, respectively. however, the desired temperature differences were set lower at haibei (1.2 degrees c daytime, 1.7 degrees c night) than cheyenne (1.5 degrees c daytime, 3.0 degrees c night), and cheyenne is a windier site. thus, we conclude that these hexagonal arrays of ceramic infrared heaters can be a successful temperature free-air-controlled enhancement (t-face) system for warming ecosystem field plots.
英文摘要	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 development of arrays of more powerful and efficient infrared heaters with ceramic heating elements. by tilting the heaters at 45 degrees 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 [eta(h) (%); 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: eta(h) = 10 + 25exp(-0.17 u), where u is wind speed at 2 m height (m s(-1)). graphs are presented to estimate operating costs from degrees of warming, two types of plant canopy, and site windiness. four such arrays were deployed over plots of grass at haibei, qinghai, china and another at cheyenne, wyoming, usa, along with corresponding reference plots with dummy heaters. proportional integral derivative systems with infrared thermometers to sense canopy temperatures of the heated and reference plots were used to control the heater outputs. over month-long periods at both sites, about 75% of canopy temperature observations were within 0.5 degrees c of the set-point temperature differences between heated and reference plots. electrical power consumption per 3-m-diameter plot averaged 58 and 80 kw h day(-1) for haibei and cheyenne, respectively. however, the desired temperature differences were set lower at haibei (1.2 degrees c daytime, 1.7 degrees c night) than cheyenne (1.5 degrees c daytime, 3.0 degrees c night), and cheyenne is a windier site. thus, we conclude that these hexagonal arrays of ceramic infrared heaters can be a successful temperature free-air-controlled enhancement (t-face) system for warming ecosystem field plots.
学科主题	生物科学
WOS标题词	science & technology ; life sciences & biomedicine
类目[WOS]	biodiversity conservation ; ecology ; environmental sciences
研究领域[WOS]	biodiversity & conservation ; environmental sciences & ecology
关键词[WOS]	climate-change ; terrestrial ecosystems ; northern peatlands ; elevated co2 ; temperature ; microclimate ; performance ; grassland ; prairie
收录类别	SCI
语种	英语
WOS记录号	WOS:000253313400010
公开日期	2009-12-07
内容类型	期刊论文
源URL	[http://ir.nwipb.ac.cn/handle/363003/1233]
专题	西北高原生物研究所_中国科学院西北高原生物研究所
作者单位	1.USDA ARS, US Arid Land Agr Res Ctr, Maricopa, AZ 85238 USA 2.Chinese Acad Sci, NW Inst Plateau Biol, Key Lab Adaptat & Evolut Plateau Biota, Xining 810008, Peoples R China 3.USDA ARS, Crops Res Lab, Ft Collins, CO USA
推荐引用方式 GB/T 7714	Kimball, Bruce A.,Conley, Matthew M.,Wang, Shiping,et al. Infrared heater arrays for warming ecosystem field plots[J]. global change biology,2008,14(2):309-320.
APA	Kimball, Bruce A..,Conley, Matthew M..,Wang, Shiping.,Lin, Xingwu.,Luo, Caiyun.,...&Smith, David.(2008).Infrared heater arrays for warming ecosystem field plots.global change biology,14(2),309-320.
MLA	Kimball, Bruce A.,et al."Infrared heater arrays for warming ecosystem field plots".global change biology 14.2(2008):309-320.