气候变化领域集成服务门户(CCPortal): Dew frequency across the US from a network of in situ radiometers

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DOI	10.5194/hess-23-1179-2019
	Dew frequency across the US from a network of in situ radiometers
	Ritter F.; Berkelhammer M.; Beysens D.
发表日期	2019
ISSN	1027-5606
起始页码	1179
结束页码	1197
卷号	23 期号:2
英文摘要	Dew formation is a ubiquitous process, but its importance to energy budgets or ecosystem health is difficult to constrain. This uncertainty arises largely because of a lack of continuous quantitative measurements on dew across ecosystems with varying climate states and surface characteristics. This study analyzes dew frequency from the National Ecological Observatory Network (NEON), which includes 11 grasslands and 19 forest sites from 2015 to 2017. Dew formation is determined at 30 min intervals using in situ radiometric surface temperatures from multiple heights within the canopy along with meteorological measurements. Dew frequency in the grasslands ranges from 15 % to 95 % of the nights with a strong linear dependency on the nighttime relative humidity (RH), while dew frequency in the forests is less frequent and more homogeneous (25±14 %, 1 standard deviation - SD). Dew mostly forms at the top of the canopy for the grasslands due to more effective radiative cooling and within the canopy for the forests because of higher within the canopy RH. The high temporal resolution of our data showed that dew duration reaches maximum values (ĝ1/46-15 h) for RHĝ1/496 % and for a wind speed of $ĝ1/4 0.5 m s^{- 1}$ , independent of the ecosystem type. While dew duration can be inferred from the observations, dew yield needs to be estimated based on the Monin-Obukhov similarity theory. We find yields of $0.14 \pm 0.12 mm {night}^{- 1}$ (1 SD from nine grasslands) similar to previous studies, and dew yield and duration are related by a quadratic relationship. The latent heat flux released by dew formation is estimated to be non-negligible ( $ĝ1/4 10 W m^{- 2}$ ), associated with a Bowen ratio of ĝ1/43. The radiometers used here provide canopy-averaged surface temperatures, which may underestimate dew frequency because of localized cold points in the canopy that fall below the dew point. A statistical model is used to test this effect and shows that dew frequency can increase by an additional ĝ1/45 % for both ecosystems by considering a reasonable distribution around the mean canopy temperature. The mean dew duration is almost unaffected by this sensitivity analysis. In situ radiometric surface temperatures provide a continuous, non-invasive and robust tool for studying dew frequency and duration on a fine temporal scale. © Author(s) 2019.
语种	英语
scopus关键词	Atmospheric temperature; Budget control; Estimation; Forestry; Heat flux; Radiative Cooling; Radiometers; Radiometry; Sensitivity analysis; Surface properties; Uncertainty analysis; Wind; High temporal resolution; Meteorological measurements; Monin-Obukhov similarity theory; Quantitative measurement; Radiometric surface temperatures; Statistical modeling; Surface characteristics; Surface temperatures; Ecosystems; Bowen ratio; cooling; dew; ecosystem dynamics; ecosystem health; forest ecosystem; frequency analysis; grassland; in situ measurement; meteorology; network analysis; quantitative analysis; radiometer; relative humidity; surface temperature; uncertainty analysis; United States
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159742
作者单位	Ritter, F., Department of Earth and Environmental Sciences, University of Illinois at Chicago, Illinois, United States; Berkelhammer, M., Department of Earth and Environmental Sciences, University of Illinois at Chicago, Illinois, United States; Beysens, D., Physique et Mécanique des Milieux Hétérogènes, CNRS, ESPCI, PSL Research University, Sorbonne Université, Sorbonne Paris Cité, Paris, France, OPUR, Paris, France
推荐引用方式 GB/T 7714	Ritter F.,Berkelhammer M.,Beysens D.. Dew frequency across the US from a network of in situ radiometers[J],2019,23(2).
APA	Ritter F.,Berkelhammer M.,&Beysens D..(2019).Dew frequency across the US from a network of in situ radiometers.Hydrology and Earth System Sciences,23(2).
MLA	Ritter F.,et al."Dew frequency across the US from a network of in situ radiometers".Hydrology and Earth System Sciences 23.2(2019).