Impact of anthropogenic heat on urban climate in Tokyo

184

102

Abstract:The anthropogenic heat release, Q F , has been estimated for the old European agglomeration of Toulouse (France) from February 2004 to March 2005 in the frame of the CAPITOUL experiment. Surface energy balance (SEB) measurements have been conducted at a downtown site, over a dense urban area. A method is proposed to estimate Q F at the local scale around this site from observations, as the daily residual term of the SEB equation. The values obtained from this method are in agreement with what can be expected: Q F estimates are around 70 W m −2 during winter and 15 W m −2 during summer. On a larger scale (that of the agglomeration), an energy consumption inventory was conducted for the period of the field campaign with a 1-day temporal resolution and a 100-m spatial resolution. The estimates of Q F obtained with this second method were analysed at the local scale around the measurements site, and compared with estimates computed from the energy budget observations. For the winter period, both estimates are in good agreement. For the summer period, the method based on SEB measurements seems to underestimate Q F which is estimated around 30 W m −2 from the inventory. The simultaneous estimate of Q F , with these two independent methods is a strength of this study.At the scale of the agglomeration, the basal state of energy consumption (observed during the summer period) varies between 25 W m −2 for the densest areas to less than 5 W m −2 for the residential suburban areas. In the regions crossed by the major roads, the traffic is the major source during summer. Then during the winter period, Q F can reach 100 W m −2 in the densest areas of Toulouse whereas it ranges between 5 and 25 W m −2 in the suburban areas.

Section: Estimates Of Q F From the Inventory Of Energy Consumptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Anthropogenic heat release in an old European agglomeration (Toulouse, France)

Pigeon

Legain

Durand

et al. 2007

184

102

“…In cities, or parts thereof with intensive industrial or commercial activity, or where there is significant winter heating or summer air conditioning, this term may also be a significant component of the energy balance (Oke, 1987;Klysik, 1996;Ichinose et al, 1999). Q F may be estimated from energy consumption estimates and empirical traffic flow data (Oke, 1987;Grimmond, 1992;Sailor and Lu, 2004).…”

Section: Introductionmentioning

confidence: 99%

Heat storage and anthropogenic heat flux in relation to the energy balance of a central European city centre

Offerle

Grimmond

Fortuniak

2005

191

151

The role of net heat storage Q S and anthropogenic heat Q F are considered in the surface energy balance for a downtown area in Łódź, Poland, for a 2 year period. Eddy covariance measurements provide estimates of the turbulent heat fluxes and radiometric measurements of the net all-wave radiation. A method to determine Q S based on representative surface temperature sampling is employed and compared with results from two other models. Results show that Q S is an important flux on the scale of hours to days and that it can be more than 10 W m −2 , on average, for periods of a week or more. By incorporating Q S estimates over hourly intervals, Q F was then determined as the residual of the energy balance. Using the approach, Q F averaged 32 W m −2 from October to March (60% of available energy), and −3 W m −2 from June to August. The physically unrealistic negative values for the summer period may suggest underestimation of turbulent fluxes, but no causal factor was identified. Although energy balance closure was close to 100% throughout the year, there was weaker agreement in the winter. This is attributed to errors in estimates of Q S and variation in Q F . Results highlight the need for future investigations of the urban surface energy balance to incorporate more complete measurements and estimates of Q S .

“…This indicates that urbanization, as evidenced by a decrease in greenery and an increase in anthropogenic heat, has advanced the progress of this urban heat island. Ichinose et al (1999) evaluated the impact of anthropogenic heat and greenery coverage ratio on the urban climate across the Tokyo metropolitan area using CSUMM. The air temperature without anthropogenic heat would be about 1.5°C lower at 22:00 h in Otemachi than it is at present.…”

Section: Classification Of Assessment Toolsmentioning

confidence: 99%

Recent development of assessment tools for urban climate and heat‐island investigation especially based on experiences in Japan

Ooka

2007

Abstract:In recent years, problems concerning the urban climate-including the urban heat-island effect and urban air pollution -have attracted much attention in terms of the widespread urbanization in many parts of the world, including Japan. Assessment tools for urban climate are very important to understand effective countermeasures for heat-island mitigation. In this paper, various assessment tools are introduced and classified according to corresponding modelling scales. Special attention is given to the recent progress in Japan. It is shown that these assessment tools are very powerful at estimating the effectiveness of countermeasures. Furthermore, these assessment tools should become design tools for practical applications in the future.