scholarly journals Spatial variations of sensible heat flux over an urban area measured using Doppler lidar

2008 ◽  
Vol 15 (3) ◽  
pp. 367-380 ◽  
Author(s):  
J. C. Davis ◽  
C. G. Collier ◽  
F. Davies ◽  
K. E. Bozier
2012 ◽  
Vol 12 (17) ◽  
pp. 7881-7892 ◽  
Author(s):  
H. Z. Liu ◽  
J. W. Feng ◽  
L. Järvi ◽  
T. Vesala

Abstract. Long-term measurements of carbon dioxide flux (Fc) and the latent and sensible heat fluxes were performed using the eddy covariance (EC) method in Beijing, China over a 4-yr period in 2006–2009. The EC setup was installed at a height of 47 m on the Beijing 325-m meteorological tower in the northwest part of the city. Latent heat flux dominated the energy exchange between the urban surface and the atmosphere in summer, while sensible heat flux was the main component in the spring. Winter and autumn were two transition periods of the turbulent fluxes. The source area of Fc was highly heterogeneous, which consisted of buildings, parks, and highways. It was of interest to study of the temporal and spatial variability of Fc in this urban environment of a developing country. Both on diurnal and monthly scale, the urban surface acted as a net source for CO2 and downward fluxes were only occasionally observed. The diurnal pattern of Fc showed dependence on traffic and the typical two peak traffic patterns appeared in the diurnal cycle. Also Fc was higher on weekdays than on weekends due to the higher traffic volumes on weekdays. On seasonal scale, Fc was generally higher in winter than during other seasons likely due to domestic heating during colder months. Total annual average CO2 emissions from the neighborhood of the tower were estimated to be 4.90 kg C m−2 yr−1 over the 4-yr period. Total vehicle population was the most important factor controlling the inter-annual variability of Fc in this urban area.


2009 ◽  
Vol 18 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Jenny Davis ◽  
Christopher G. Clare Collier ◽  
Fay Davies ◽  
Guy N. Pearson ◽  
Ralph Burton ◽  
...  

Author(s):  
Rafael João Sampaio ◽  
Daniel Andres Rodriguez ◽  
Celso Von Randow ◽  
Fabricio Polifke da Silva ◽  
Afonso Augusto Magalhães de Araújo ◽  
...  

Author(s):  
J C Davis ◽  
F Davies ◽  
C G Collier ◽  
G N Pearson

1990 ◽  
Vol 36 (123) ◽  
pp. 217-221 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole B. Olesen

AbstractDaily ice ablation on two outlet glaciers from the Greenland ice sheet, Nordbogletscher (1979–83) and Qamanârssûp sermia (1980–86), is related to air temperature by a linear regression equation. Analysis of this ablation-temperature equation with the help of a simple energy-balance model shows that sensible-heat flux has the greatest temperature response and accounts for about one-half of the temperature response of ablation. Net radiation accounts for about one-quarter of the temperature response of ablation, and latent-heat flux and errors account for the remainder. The temperature response of sensible-heat flux at QQamanârssûp sermia is greater than at Nordbogletscher mainly due to higher average wind speeds. The association of high winds with high temperatures during Föhn events further increases sensible-heat flux. The energy-balance model shows that ablation from a snow surface is only about half that from an ice surface at the same air temperature.


1977 ◽  
Vol 11 (2) ◽  
pp. 147-154 ◽  
Author(s):  
R. L. Desjardins

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