Dew amounts and its correlations with meteorological factors in urban landscapes of Guangzhou, China

Youhua, Ye; Zhou, Kai; Song, Liying; Jin, Jianhua; Shaolin, Peng

doi:10.1016/j.atmosres.2007.03.001

Cited by 72 publications

(47 citation statements)

References 34 publications

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“…High correlation of dew with RH (R 2 = 0.89) and path analysis result indicate that RH was an important factor in controlling dew. This result is similar to previous reports [5,32,34,54]. We found that dew was low and approximately constant at RH below 75%, and increased sharply when RH exceeded 75%.…”

Section: Control Of Dewsupporting

confidence: 82%

“…Light wind favors dew formation [57] as it can bring moisture which facilitates dew formation and extend the dew duration. Previous studies have shown that most dew events occur at W s below 2 m¨s´1 [54,58]. Other studies have also shown that a wind speed of 3-3.6 m¨s´1 is favorable for dew formation, while a wind speed greater than 4.7 m¨s´1 adversely affects dew formation [8].…”

Section: Control Of Dewmentioning

confidence: 97%

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Dynamics of Dew in a Cold Desert-Shrub Ecosystem and Its Abiotic Controls

et al. 2016

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Abstract:The temporal dynamics of dew formation in cold desert-shrub ecosystems are still poorly understood. We examined dew and its abiotic controls in a shrubland in northwestern China with continuous eddy-covariance measurements of latent heat fluxes gathered over the growing-season of 2012. The dew amount was larger in mid-summer than in spring and autumn, but the dew duration was shorter in summer (from~10:00 p.m. to~6:30 a.m.) than in spring and autumn (from~8:30 p.m. to~7:30 a.m.). Dew occurred on 85% (166 days) of growing-season days, with monthly means ranging from 0.09 to 0.16 mm day´1. Dew was dominantly and positively controlled by Relative Humidity (RH), which explained 89% of its variation. Soil heat flux (G), air temperature (T a ), wind speed (W s ), Soil Water Content (SWC) and Vapor Pressure Deficit (VPD) also influenced dew formation. The most favorable conditions for dew formation were at T a < 17˝C and RH > 75%. The Penman-Monteith equation predicted actual dew reasonably well. The predicted growing-season dew amount (21.3 mm) was equivalent to 7.2% and 8.9% of corresponding rainfall and evapotranspiration, respectively. It is suggested that dew could be a stable and continuous source of water that helps desert plants survive during warm summers.

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Section: Control Of Dewsupporting

confidence: 82%

Section: Control Of Dewmentioning

confidence: 97%

Dynamics of Dew in a Cold Desert-Shrub Ecosystem and Its Abiotic Controls

et al. 2016

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“…This finding might be attributable to Vancouver's temperate maritime climate, where the relative humidity was higher and the vapours were easier to condense during night-time. The intensity of dew condensation in the present study area was higher than the dew amount of the Guangzhou Forest Park (0.034 mm/d), as well as the commercial areas (0.013 mm/d), residential areas (0.009 mm/d), and industrial areas (0.022 mm)/d) with large human disturbance [25]. This phenomenon was mainly due to the larger diurnal temperature variation and smaller wind speed in the experimental area than Guangzhou, which was prone to heavy dew condensation.…”

Section: Classification Criteria Between Fog-haze and Normal Weathersmentioning

confidence: 92%

Influence of Fog-Haze on Dew Condensation in Urban Areas

Xu¹,

Zhu

Pan

et al. 2018

Teh. vjesn.

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Abstract:In recent years, fog-haze weather has frequently occurred in urban ecosystem, with accompanied dew condensation in the surface layer. Dew formation plays an important role in air purification, which takes fine aerosols in the atmosphere as the condensation nuclei. However, the influence of fog-haze on dew condensation remains unclear. Thus, this study aims to evaluate the influences of fog-haze days on the frequency, intensity, and duration of dew condensation, to reveal the factors relevant to dew condensation during weather pollution, and to improve the air quality in fog-haze days. The monitor-based direct weighing method was employed in this study to observe the vapour condensation in urban greenbelt under fog-haze and normal weather conditions during the frost-free season (April-October 2017) in Changchun, China. The differences in dew condensation intensity and frequency were discriminated under different weather conditions. Then, the influences of fog-haze days on the vapour condensation were analyzed by monitoring the velocity and duration of dew condensation in polluted weather. Finally, a program for improving air quality was proposed based on the analysis of major meteorological factors that affect the dew condensation during the fog-haze days. Results show that the dew condensation velocity decreases significantly (P < 0.01) from 0.0067 mm/h in normal weather to 0.0026 mm/h in a fog-haze day, whereas the condensation duration is prolonged. The dew condensation intensities are 0.064, 0.045, and 0.051 mm/d under fog, haze, and normal weather conditions, respectively, and the fog-haze weather has no significant effect on the frequency or intensity of dew condensation (P > 0.05). The particulate matter concentration, wind speed, air pressure, relative humidity, and solar radiation are the main factors that affect the vapour transport during the fog-haze days. Artificial increase of surface layer vapours can promote the particulates to absorb vapours fully and settle to the ground in the form of dew, thereby reducing the particulate matter concentration within the scope of human activities. The present study supplements the eigenvalues for dew condensation in urban areas during special pollution periods and reveals the influence of fog-haze on the night time vapour condensation in urban areas. Findings of this study provide theoretical basis for further developing the programs for controlling fog-haze weather and improving urban air quality.

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“…In an urban ecosystem, the difference in dew intensity in various functional areas was obvious. Ye et al stated that the highest mean dew intensity in the urban area was observed in the forest landscape (0.034 mm/night), followed by the industrial landscape (0.022 mm/night), the commercial landscape (0.013 mm/night), and the residential landscape (0.009 mm/night) [20]. In Vancouver, BC, the dew frequency in city was close to the suburbs [23].…”

Section: Dew Intensity and Dewfall In Different Ecosystemsmentioning

confidence: 99%

“…The preceding research mainly collected dew water and analyzed the water quality of dew but did not measure the dew amount. Ye used synthetic velvet to measure dew intensity in the different landscapes of Guangzhou City, China [20]. However, the same monitor was used for measuring dew in different landscapes of the city, and the dew water study monitored the daily dew per unit area with no concern of the annual dewfall.…”

Section: Introductionmentioning

confidence: 99%

A novel method for monitoring urban dew condensation and its application

Zhu

Sun

et al. 2017

Teh. vjesn.

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Original scientific paper Dew is crucial moisture input for the water balance of urban ecosystems. Dew, which is an important environmental factor of urban ecosystem, can be easily absorbed by plant leaves and provide nutrients (N, P, and K) to plants. Moreover, dew formation is important in air purification. However, few internationally accepted standard methods or instruments are currently available for measuring dew amount in urban ecosystems because of the small dew amount. In order to accurately measure the night water vapour condensation and evaluate the effects of surface hardening to near-surface water cycle, this study monitored dew condensation and combined dew with leaf area index, and a novel method was proposed for monitoring and calculating dew amount in different underlying surfaces in urban ecosystems. The Changchun City in China was considered as an example and the proposed method was used to observe dew condensation in different functional areas of the city during the frost-free period (April 2016 to October 2016). Finally, the main meteorological factors affecting dew condensation were analyzed by summarizing the rule of vapour condensation; moreover, dew intensity and annual dewfall of different landscapes were obtained. Results indicate that greenbelt landscapes are important sites for dew deposition. The landscapes of dew intensity, in descending order, are greenbelt landscape, bare landscape, and road landscape (P < 0.01). Relative humidity is the main factor affecting water vapour migration. Dewfall amounts in the greenbelt, road, and bare landscapes are 61.43, 0.56, and 1.23 mm, respectively. The annual dewfall is 22.98 mm in Changchun according to the proportion of each landscape. The dew-monitoring method system in urban area is improved and the wet deposition from vapour condensation of different surfaces underlying at night is added. The method provides theoretical reference for further research on revealing the near-surface water cycle. Keywords: dew intensity; dewfall; landscape; urban ecosystem Nova metoda za praćenje kondenzacije rose u gradu i njezina primjenaIzvorni znanstveni članak Rosa predstavlja unos vlage bitan za održavanje razine vode gradskih ekosustava. Rosu, koja je važan ekološki faktor gradskih ekosustava, lišće biljaka lako apsorbira i tako se opskrbljuje hranjivim tvarima (N, P i K). Osim toga, stvaranje rose važno je u pročišćavanju zraka. Ipak, ima malo internacionalno prihvaćenih standardnih metoda ili instrumenata trenutačno raspoloživih za mjerenje količine rose u urbanim ekosustavima, zbog male količine rose. U svrhu točnog mjerenja kondenzacije vodene pare noću i procjene učinaka stvrdnjavanja površine na tokove vode blizu površine, u radu se prati kondenzacija rose i kombinira rosa s indeksom površine lista te se predlaže nova metoda za praćenje i izračunavanje količine rose u različitim površinama urbanih ekoloških sustava. Grad Changchun u Kini uzet je kao primjer i predloženom metodom se promatrala kondenzacija rose u njegovim različitim funkcionalnim ...

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Dew amounts and its correlations with meteorological factors in urban landscapes of Guangzhou, China

Cited by 72 publications

References 34 publications

Dynamics of Dew in a Cold Desert-Shrub Ecosystem and Its Abiotic Controls

Dynamics of Dew in a Cold Desert-Shrub Ecosystem and Its Abiotic Controls

Influence of Fog-Haze on Dew Condensation in Urban Areas

A novel method for monitoring urban dew condensation and its application

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