scholarly journals RESEARCH ON THERMAL ENVIRONMENT IN URBAN AREA : Part 7 Observations of sensible heat fluxes in a rural city

1991 ◽  
Vol 427 (0) ◽  
pp. 21-27
Author(s):  
Tatsuo OKA ◽  
Tetsuo FUWA
Keyword(s):  
Urban Area ◽  
Thermal Environment ◽  
Heat Fluxes ◽  
Sensible Heat

scholarly journals Four-year (2006–2009) eddy covariance measurements of CO<sub>2</sub> flux over an urban area in Beijing

2012 ◽  
Vol 12 (17) ◽  
pp. 7881-7892 ◽  
Author(s):  
H. Z. Liu ◽  
J. W. Feng ◽  
L. Järvi ◽  
T. Vesala
Keyword(s):  
Heat Flux ◽  
Urban Area ◽  
Eddy Covariance ◽  
Sensible Heat Flux ◽  
Source Area ◽  
Carbon Dioxide Flux ◽  
Heat Fluxes ◽  
Urban Surface ◽  
Sensible Heat ◽  
Main Component

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.

A Study on the Effects of the Anthropogenic Heat Fluxes on the Temperature Distribution in an Urban Area

2020 ◽  
Author(s):  
Da-Som Mun ◽  
Jae-Jin Kim
Keyword(s):  
Urban Area ◽  
Thermal Environment ◽  
Heat Fluxes ◽  
Anthropogenic Heat ◽  
Target Area ◽  
Cfd Model ◽  
Residential Areas ◽  
Energy Usage ◽  
Night Time ◽  
Cfd Simulations

&lt;p&gt;In this study, we investigated the effects of the anthropogenic heat caused by the energy usage on the air temperature distributions in an urban area using a CFD model. We calculated the anthropogenic heat fluxes using a top-down method with monthly and hourly allocation coefficients and the total amount of the yearly electrical energy usage of buildings. To construct the buildings and to estimate the anthropogenic heat fluxes in the CFD model for the target area, we used the land use and GIS data. We conducted the CFD simulations for the heatwave period (2018.08.02 ~ 2018.08.08) in a building-congested district around the Seoul ASOS (ASOS 108) to see how the anthropogenic heat fluxes affected the thermal environment in the target area. The target area is mostly composed of commercial and residential areas. The temperature increased near the roads and buildings. At the night time, the temperature increase near the buildings with high anthropogenic heat fluxes was more significant than the daytime. The comparison with the ASOS-observed temperatures showed that the inclusion of the anthropogenic heat fluxes improved the CFD simulations of temperatures.&lt;/p&gt;

OBSERVATION ON HEAT FLUXES ABOVE THE TERRESTRIAL SURFACES IN THE CENTER OF URBAN AREA AND THE BAY IN TOKYO

1994 ◽  
Vol 59 (463) ◽  
pp. 65-73 ◽  
Author(s):  
Hidetaka KOMIYA ◽  
Tatsuo OKA ◽  
Taizou SHIMOKAWA ◽  
Hiroyuki AKAGAWA ◽  
Junn SUGIYAMA
Keyword(s):  
Urban Area ◽  
Heat Fluxes

scholarly journals Midwinter melts in the Canadian prairies: energy balance and hydrological effects

2019 ◽  
Vol 23 (4) ◽  
pp. 1867-1883 ◽  
Author(s):  
Igor Pavlovskii ◽  
Masaki Hayashi ◽  
Daniel Itenfisu
Keyword(s):  
Surface Runoff ◽  
Hydrological Cycle ◽  
Remote Sensing Data ◽  
Heat Fluxes ◽  
Sensible Heat ◽  
Net Radiation ◽  
Present Climate ◽  
Canadian Prairies ◽  
Energy Inputs ◽  
Hydrological Effects

Abstract. Snowpack accumulation and depletion are important elements of the hydrological cycle in the Canadian prairies. The surface runoff generated during snowmelt is transformed into streamflow or fills numerous depressions driving the focussed recharge of groundwater in this dry setting. The snowpack in the prairies can undergo several cycles of accumulation and depletion in a winter. The timing of the melt affects the mechanisms of snowpack depletion and their hydrological implications. The effects of midwinter melts were investigated at four instrumented sites in the Canadian prairies. Unlike net radiation-driven snowmelt during spring melt, turbulent sensible heat fluxes were the dominant source of energy inputs for midwinter melt occurring in the period with low solar radiation inputs. Midwinter melt events affect several aspects of hydrological cycle with lower runoff ratios than subsequent spring melt events, due to their role in the timing of the focussed recharge. Remote sensing data have shown that midwinter melt events regularly occur under the present climate throughout the Canadian prairies, indicating applicability of the study findings throughout the region.

A Positive Feedback Process Related to the Rapid Development of an Extratropical Cyclone over the Kuroshio/Kuroshio Extension

2018 ◽  
Vol 146 (2) ◽  
pp. 417-433 ◽  
Author(s):  
Hidetaka Hirata ◽  
Ryuichi Kawamura ◽  
Masaya Kato ◽  
Taro Shinoda
Keyword(s):  
Water Vapor ◽  
Positive Feedback ◽  
Heat Supply ◽  
Rapid Development ◽  
Kuroshio Extension ◽  
Heat Fluxes ◽  
Latent Heating ◽  
Sensible Heat ◽  
Feedback Process ◽  
The Kuroshio

Abstract The active roles of sensible heat supply from the Kuroshio/Kuroshio Extension in the rapid development of an extratropical cyclone, which occurred in the middle of January 2013, were examined by using a regional cloud-resolving model. In this study, a control experiment and three sensitivity experiments without sensible and latent heat fluxes from the warm currents were conducted. When the cyclone intensified, sensible heat fluxes from these currents become prominent around the cold conveyor belt (CCB) in the control run. Comparisons among the four runs revealed that the sensible heat supply facilitates deepening of the cyclone’s central pressure, CCB development, and enhanced latent heating over the bent-back front. The sensible heat supply enhances convectively unstable conditions within the atmospheric boundary layer along the CCB. The increased convective instability is released by the forced ascent associated with frontogenesis around the bent-back front, eventually promoting updraft and resultant latent heating. Additionally, the sensible heating leads to an increase in the water vapor content of the saturated air related to the CCB through an increase in the saturation mixing ratio. This increased water vapor content reinforces the moisture flux convergence at the bent-back front, contributing to the activation of latent heating. Previous research has proposed a positive feedback process between the CCB and latent heating over the bent-back front in terms of moisture supply from warm currents. Considering the above two effects of the sensible heat supply, this study revises the positive feedback process.

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