Urban Surface Energy Balance Models: Model Characteristics and Methodology for a Comparison Study - Meteorological and Air Quality Models for Urban Areas - page 100

Table 11.10 Methods used to calculate anthropogenic heat flux (Q F )

Model Anthropogenic heat flux methods

BEP02, BEP05,
SUNBEEM

Partially accounted for by imposing a fixed temp at the building
interior

CAT Prescribed, adjusted for diurnal variations

CLMU Prescribed traffic fluxes, parameterized waste heat fluxes from

heating/ air conditioning

ENVImet From heat transfer equations through walls

HIRLAM-U Calculated (offline) as a temporal & spatial function of available

parameters by 4 methods (emission, night light, land-use,
population) (Baklanov et al., 2005)

GCTTC Prescribed per vehicle (for vehicles only)

MM5u, NSLUCM Calculated (offline) as a temporal & spatial function of the

anthropogenic emissions

MOSES2T, MOSES1T,
MOUSES, SUEB

Not modelled itself but possible to be included for calculation of
turbulent fluxes

MUCM Modelled by Kikegawa et al. Offline

MUKLIMO Heat fluxes through the walls and roofs computed with fixed temp

at the buildings interior

TEB, TEB07 TUF2D,
TUF3D

Domestic heating computed

UCLM Not directly included. Heat can be added to building interior.

VUCM, SM2U Prescribed bulk value

some models. This flux is most significant in the wintertime when the additional
energy from human sources is most important relative to the net all wave radia-
tion. That said, in many urban areas energy use is becoming increasingly significant
in the summer due to air conditioning usage (Watson et al., 1997). Anthropogenic
heat flux may only be significant in areas with very high flux densities (e.g. Tokyo,
Ichinose et al., 1999). At key times of the day and night, and specifically at transi-
tions between them, this flux could become more significant.
The turbulent sensible heat fluxes are typically modelled using some form of
resistance scheme (Table 11.11). Differences depend on the degree of detail of the
surface to be modelled; i.e. a bulk surface resistance or a resistance network account-
ing for differences between surfaces. Varying approaches are taken for these resis-
tances, ranging, for example, from those based on the Penman-Monteith equation
(e.g. LUMPS) to resistance networks that take into account changes in stability
and the orientation of the surface that is shedding the heat (e.g. TUF3D). Corre-
spondingly, a number of different resistance schemes are used (e.g. Rowley, 1930;
Clarke, 1985; Zilitinkevich, 1995; Guilloteau, 1998; Harman et al., 2004b). The
methods used to determine the stability functions are important because they feed-
back and impact on the outgoing longwave radiation. Many of the methods assume
that Monin-Obukhov similarity holds, but this may not be applicable within the
urban canyon (Roth, 2000). However, given the lack of well-tested alternatives, this
may be the most appropriate set of assumptions.