Simulating air temperature in an urban street canyon in all weather conditions using measured data at a reference meteorological station

The definitive version may be found at www.wiley.com Copyright © 2006 Royal Meteorological SocietyA model is proposed that adapts data from a standard meteorological station to provide realistic site-specific air temperature in a city street exposed to the same meso-scale environment. In addition to a rudimentary description of the two sites, the canyon air temperature (CAT) model requires only inputs measured at standard weather stations; yet it is capable of accurately predicting the evolution of air temperature in all weather conditions for extended periods. It simulates the effect of urban geometry on radiant exchange; the effect of moisture availability on latent heat flux; energy stored in the ground and in building surfaces; air flow in the street based on wind above roof height; and the sensible heat flux from individual surfaces and from the street canyon as a whole. The CAT model has been tested on field data measured in a monitoring program carried out in Adelaide, Australia, in 2000-2001. After calibrating the model, predicted air temperature correlated well with measured data in all weather conditions over extended periods. The experimental validation provides additional evidence in support of a number of parameterisation schemes incorporated in the model to account for sensible heat and storage flux. Copyright © 2006 Royal Meteorological Society

Climate Information for Improved Planning and Management of Mega Cities (Needs Perspective)

The majority of the population of the planet (6.6 billion) now live in urban areas, which have distinct impacts upon climate at scales from the local to the global. This urban effect is due to the physical form of the city (its three-dimensional geometry and material composition) and its functions (the day-to-day activity patterns that generate emissions of waste heat and materials into the overlying air). While a substantial body of knowledge on the science of urban climates has been developed over the past fifty years, there is little evidence that this knowledge is incorporated into urban planning and design practice. This paper focuses on this gap by examining the nature of urban climate expertise and the needs of those that make decisions about urban areas. In conclusion it makes recommendations to maintain and enhance urban observations and data; to improve understanding of local, regional and global climate linkages; to develop tools for practical planning; and to disseminate urban climate knowledge and its relevance to urban planning to both practicing meteorologists and urban decision makers

Cross sections for the excitation of isovector charge-exchange resonances in 208Tl

The Glauber approximation for the treatment of heavy-ion scattering, has already been shown to give reliable predictions for the reaction cross section in the particular case of intermediate energy charge-exchange processes. In the present work, we couple a Glauber-type model to microscopic Random Phase Approximation calculations of the charge-exchange excitations of $^{208}$Pb. The aim is to solve the longstanding question whether the very elusive charge-exchange isovector monopole has been really identified in the past experiments, or other multipoles were prevalent in the observed spectra.Comment: text + 4 figures; accepted for publication in Phys. Rev.

Splitting of the Dipole and Spin-Dipole Resonances

Cross sections for the 90,92,94Zr(p,n) reactions were measured at energies of 79.2 and 119.4 MeV. A phenomenological model was developed to describe the variation with bombarding energy of the position of the L=1 peak observed in these and other (p,n) reactions. The model yields the splitting between the giant dipole and giant spin dipole resonances. Values of these splittings are obtained for isotopes of Zr and Sn and for 208Pb.Comment: 14 pages, 4 figure

Complete Set of Polarization Transfer Observables for the 12C(p,n)^{12}{\rm C}(p,n) Reaction at 296 MeV and 0∘^{\circ}

A complete set of polarization transfer observables has been measured for the $^{12}{\rm C}(p,n)$ reaction at $T_p=296 {\rm MeV}$ and $\theta_{\rm lab}=0^{\circ}$. The total spin transfer $\Sigma(0^{\circ})$ and the observable $f_1$ deduced from the measured polarization transfer observables indicate that the spin--dipole resonance at $E_x \simeq 7 {\rm MeV}$ has greater $2^-$ strength than $1^-$ strength, which is consistent with recent experimental and theoretical studies. The results also indicate a predominance of the spin-flip and unnatural-parity transition strength in the continuum. The exchange tensor interaction at a large momentum transfer of $Q \simeq 3.6 {\rm fm}^{-1}$ is discussed.Comment: 4 pages, 4 figure

geo climatic applicability of direct evaporative cooling in italy

This chapter focuses on the climatic applicability of passive direct (downdraught) evaporative cooling (PDEC) techniques in the provincial capital cities of Italy. First, a PDEC potentiality map was produced using a previously developed method based on three variables: wet bulb depression, summer comfort air temperature threshold (25 °C) and cooling degree hours (CDHs). Second, an applicability map was produced by comparing the PDEC potentiality map to the local cooling energy demand. Third, a new method is presented including a calculation of the residual local cooling energy demand, i.e. residual CDH, related to air treatment by direct evaporative cooling. These residual CDH values were calculated considering different step-wise increasing outlet temperatures (WBT; WBT + 1 °C; …; WBT + 5 °C) as a function of the covered amount of wet bulb depression. Finally, three cities chosen as being representative of their respective Italian climatic macro-zones were selected in order to assess in greater detail the yearly variation of CDH aimed at supporting specific design strategies for ventilative passive cooling solutions

Bioclimatic Architecture and Urban Morphology. Studies on Intermediate Urban Open Spaces

This paper deals with the interactions between biophysical and microclimatic factors on the one hand with, on the other, the urban morphology of intermediate urban open spaces, the relationship between environmental and bioclimatic thermal comfort, and the implementation of innovative materials and the use of greenery, aimed at the users’ well-being. In particular, the thermal comfort of the open spaces of the consolidated fabrics of the city of Rome is studied, by carrying out simulations of cooling strategies relating to two scenarios applied to Piazza Bainsizza. The first scenario involves the use of cool materials for roofs, cladding surfaces, and pavement, while the second scenario, in addition to the cool materials employed in the first scenario, also includes the use of greenery and permeable green surfaces. The research was performed using summer and winter microclimatic simulations of the CFD (ENVI-met v. 3.1) type, in order to determine the dierent influences of the materials with cold colors, trees, and vegetated surfaces on the thermal comfort of the urban morphology itself. Meanwhile, the comfort assessment was determined through the physiological equivalent temperature (PET) calculated with the RayMan program. The first scenario, with the use of cool materials, improves summer conditions and reduces the urban heat island eect but does not eliminate thermal discomfort due to the lack of shaded surfaces and vegetation. The second scenario, where material renovations is matched with vegetation improvements, has a slightly bad eect on winter conditions but drastically ameliorates the summer situation, both for direct users and, thanks to the strong reduction of the urban heat island eect, to urban inhabitants as a whole

Influence of ground surface characteristics on the mean radiant temperature in urban areas

The effect of variations in land cover on mean radiant surface temperature (Tmrt) is explored through a simple scheme developed within the radiation model SOLWEIG. Outgoing longwave radiation is parameterised using surface temperature observations on a grass and an asphalt surface, whereas outgoing shortwave radiation is modelled through variations in albedo for the different surfaces. The influence of surface materials on Tmrt is small compared to the effects of shadowing. Nevertheless, altering ground surface materials could contribute to a reduction on Tmrt to reduce the radiant load during heat-wave episodes in locations where shadowing is not an option. Evaluation of the new scheme suggests that despite its simplicity it can simulate the outgoing fluxes well, especially during sunny conditions. However, it underestimates at night and in shadowed locations. One grass surface used to develop the parameterisation, with very different characteristics compared to an evaluation grass site, caused Tmrt to be underestimated. The implications of using high resolution (e.g. 15 minutes) temporal forcing data under partly cloudy conditions are demonstrated even for fairly proximal sites