A novel method for monitoring urban dew condensation and its application

Abstract

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 ...

Influence of Fog-Haze on Dew Condensation in Urban Areas

“…Moreover, Xu et al [19] revealed that the annual dew amount in their study area could reach 22.98 mm. Clearly, the dew in the urban ecosystem was not only large in amount but was also beneficial to the removal of PM 10 , PM 2.5 , and other harmful particulates within the scope of human activities (0 ÷ 3 m scale).…”

“…At half an hour before sunrise, the wooden sticks were removed, placed in the clean plastic cases correspondingly, weighed separately with a balance (0.001 g precision), and recorded. Distinguishing between night-time dew condensation and rainfall during dew days was difficult, thus, the dew amount of the day would be 0 if precipitation days occurred after sunset and before sunrise [19]. Through this method, the frequency and intensity of dew condensation in the urban ecosystem could be monitored daily.…”