Development of an improved urban emissivity model based on sky view factor for retrieving effective emissivity and surface temperature over urban areas

2016-2017 > Academic research: refereed > Publication in refereed journal201804_a bcmaAccepted ManuscriptRGCOthersHong Kong Polytechnic UniversityPublishe

Integrated Assessment of Urban Overheating Impacts on Human Life

10.1029/2022EF002682EARTHS FUTURE10

Simulation of Fall and Winter Surface Energy Balance over a Dense Urban Area Using the TEB Scheme

The Town Energy Balance (TEB) scheme computes the surface energy balance for urban areas. It is intended to be coupled with atmospheric models for numerical weather prediction, air quality forecasts or research applications. Up to now, it has been evaluated for dry and hot seasons over light industrial (Vancouver) or dense urban (Mexico City, Marseille) areas. In this study, the evaluation of TEB is extended to two other seasons, fall and winter, using measurements conducted over a dense urban area of Toulouse (France) instrumented from February 2004 to March 2005. Most of the model outputs were measured (individual components of the net radiation, sensible heat flux) as well as state variables of the model (surface temperatures of roofs, roads, walls). Great care has been taken in the design of the surface temperature measurement strategy in order to provide comparable observations to modelled estimates. Focusing on the fall and winter season, this study also proposes an evaluation of the parameterization of anthropogenic heat sources against an inventory of energy consumption

Analysis of the seasonal cycle within the first international urban land-surface model comparison

A number of urban land-surface models have been developed in recent years to satisfy the growing requirements for urban weather and climate interactions and prediction. These models vary considerably in their complexity and the processes that they represent. Although the models have been evaluated, the observational datasets have typically been of short duration and so are not suitable to assess the performance over the seasonal cycle. The First International Urban Land-Surface Model comparison used an observational dataset that spanned a period greater than a year, which enables an analysis over the seasonal cycle, whilst the variety of models that took part in the comparison allows the analysis to include a full range of model complexity. The results show that, in general, urban models do capture the seasonal cycle for each of the surface fluxes, but have larger errors in the summer months than in the winter. The net all-wave radiation has the smallest errors at all times of the year but with a negative bias. The latent heat flux and the net storage heat flux are also underestimated, whereas the sensible heat flux generally has a positive bias throughout the seasonal cycle. A representation of vegetation is a necessary, but not sufficient, condition for modelling the latent heat flux and associated sensible heat flux at all times of the year. Models that include a temporal variation in anthropogenic heat flux show some increased skill in the sensible heat flux at night during the winter, although their daytime values are consistently overestimated at all times of the year. Models that use the net all-wave radiation to determine the net storage heat flux have the best agreement with observed values of this flux during the daytime in summer, but perform worse during the winter months. The latter could result from a bias of summer periods in the observational datasets used to derive the relations with net all-wave radiation. Apart from these models, all of the other model categories considered in the analysis result in a mean net storage heat flux that is close to zero throughout the seasonal cycle, which is not seen in the observations. Models with a simple treatment of the physical processes generally perform at least as well as models with greater complexity