A new Building Energy Model coupled with an Urban Canopy Parameterization for urban climate simulations—part II. Validation with one dimension off-line simulations

Recent studies show that the fluxes exchanged between buildings and the atmosphere play an important role in the urban climate. These fluxes are taken into account in mesoscale models considering new and more complex Urban Canopy Parameterizations (UCP). A standard methodology to test an UCP is to use one-dimensional (1D) off-line simulations. In this contribution, an UCP with and without a Building Energy Model (BEM) is run 1D off-line and the results are compared against the experimental data obtained in the BUBBLE measuring campaign over Basel (Switzerland) in 2002. The advantage of BEM is that it computes the evolution of the indoor building temperature as a function of energy production and consumption in the building, the radiation coming through the windows, and the fluxes of heat exchanged through the walls and roofs as well as the impact of the air conditioning system. This evaluation exercise is particularly significant since, for the period simulated, indoor temperatures were recorded. Different statistical parameters have been calculated over the entire simulated episode in order to compare the two versions of the UCP against measurements. In conclusion, with this work, we want to study the effect of BEM on the different turbulent fluxes and exploit the new possibilities that the UCP–BEM offers us, like the impact of the air conditioning systems and the evaluation of their energy consumption.     

Global and hemispheric temperatures revisited

To characterize observed global and hemispheric temperatures, previous studies have proposed two types of data-generating processes, namely, random walk and trend-stationary, offering contrasting views regarding how the climate system works. Here we present an analysis of the time series properties of global and hemispheric temperatures using modern econometric techniques. Results show that: The temperature series can be better described as trend-stationary processes with a one-time permanent shock which cannot be interpreted as part of the natural variability; climate change has affected the mean of the processes but not their variability; it has manifested in two stages in global and Northern Hemisphere temperatures during the last century, while a second stage is yet possible in the Southern Hemisphere; in terms of Article 2 of the Framework Convention on Climate Change it can be argued that significant (dangerous) anthropogenic interference with the climate system has already occurred.     

Source and evolution of ore-forming hydrothermal fluids in the northern Iberian Pyrite Belt massive sulphide deposits (SW Spain): evidence from fluid inclusions and stable isotopes

A fluid inclusion and stable isotopic study has been undertaken on some massive sulphide deposits (Aguas Teñidas Este, Concepción, San Miguel, San Telmo and Cueva de la Mora) located in the northern Iberian Pyrite Belt. The isotopic analyses were mainly performed on quartz, chlorite, carbonate and whole rock samples from the stockworks and altered footwall zones of the deposits, and also on some fluid inclusion waters. Homogenization temperatures of fluid inclusions in quartz mostly range from 120 to 280 °C. Salinity of most fluid inclusions ranges from 2 to 14 wt% NaCl equiv. A few cases with T _h=80–110 °C and salinity of 16–24 wt% NaCl equiv., have been also recognized. In addition, fluid inclusions from the Soloviejo Mn–Fe-jaspers (160–190 °C and ˜6 wt% NaCl equiv.) and some Late to Post-Hercynian quartz veins (130–270 °C and ˜4 wt% NaCl equiv.) were also studied. Isotopic results indicate that fluids in equilibrium with measured quartz (d ¹⁸O _fluid ˜–2 to 4‰), chlorites (d ¹⁸O _fluid ˜8–14‰, dD _fluid ˜–45 to –27‰), whole rocks (d ¹⁸O _fluid ˜4–7‰, dD _fluid ˜–15 to –10‰), and carbonates (d ¹⁸O _ankerite ˜14.5–16‰, d ¹³C _fluid =–11 to –5‰) evolved isotopically during the lifetime of the hydrothermal systems, following a waxing/waning cycle at different temperatures and water/rock ratios. The results (fluid inclusions, d ¹⁸O, dD and d ¹³C values) point to a highly evolved seawater, along with a variable (but significant) contribution of other fluid reservoirs such as magmatic and/or deep metamorphic waters, as the most probable sources for the ore-forming fluids. These fluids interacted with the underlying volcanic and sedimentary rocks during convective circulation through the upper crust.     

Regional amplification of ground motion in central Mexico. Results from coda-length magnitude data and preliminary modeling

Seismic ground motion in central Mexico is amplified relative to ground motion observed at the same epicentral distance along the Pacific Coast in a frequency band that includes destructive ground motion at Mexico City. Although several hypothesis have been advanced, at present there is no generally accepted explanation of such amplification. We have analyzed coda-length magnitude data reported by Servicio Sismológico Nacional (SSN) for events recorded during 1993 to increase our understanding of the spatial distribution of this phenomenon. Our results indicate that regional amplification: (a) is detected by magnitude residual computed at each station, relative to the average of SSN network;and (b) is likely related to the crustal structure under the central portion of the Transmexican Volcanic Belt (TMVB). Finally, preliminary wave propagation modelling (using SH wave, finite difference method) suggests that crustal heterogeneity is a possible cause of regional amplification. However, if this is so, it is required that both geometry and velocity distribution vary between the coast and Mexico City.     

Reply to comment by J. L. Mateos, O. Novaro, T. H. Seligman and J. Flores on 'Can horizontal P waves be trapped and resonate in a shallow sedimentary basin?'

Using a complete mathematical formulation, we show that the trapping of horizontal P waves in a very soft shallow alluvial layer is a minor effect. These waves do not have a stable way of propagation since in order to exist they require an incident wave and are therefore incapable of resonating in the lateral direction when confined in a basin of limited extent.     

Demersal fishes in a tropical bay in southeastern Brazil: Partitioning the spatial, temporal and environmental components of ecological variation

This study analyzed the factors structuring demersal fish community in a tropical bay in southeastern Brazil. The results were used to quantify the partitioning of ecological variation among the environmental, spatial and temporal components molding the fish community. Three bay zones (inner, middle and outer) were defined according to depth and salinity gradient. Monthly samplings were conducted by bottom trawl tows during daylight hours, between October 1998 and September 1999. In each zone, three replicate samples were taken. Ninety-three fish species from 73 genera and 37 families were recorded in the 108 samples. Two demersal fish assemblages were evidenced, one in the inner and the other in the outer zone. These assemblages were characterized by changes in species composition and relative abundance. Depth, followed by transparency and salinity, influenced spatial pattern of fish assemblages. The largest part of the explained variation occurred as a result of the spatial structure of environmental variables, which means that both species and environmental variables presented similar spatial structure. The spatial effect, not the seasonal, explained the highest part of species variations. The amount of unexplained variation was relatively high (76%), even assuming that part of it is due to nondeterministic fluctuation, which could be due to local effects of unmeasured (biotic and abiotic) controlling variables. Knowing the relative importance of these factors can be of decisive importance when applying casual hypotheses in the framework of some precise ecological theory and should facilitate management, planning, and usage of bay resources.     

Port privatization in Panama

In previous papers we have looked at open registries, the Panama maritime sector and Panama Canal operations and management. No maritime study of Panama is complete, however, without a detailed look at the Panama Canal's main port system, which has enjoyed remarkable growth since the privatization of the terminal ports of Cristóbal and Balboa in 1995. This paper looks at the evolution and development of the Canal's port system; its stewardship, initially by the American authorities governing the Canal and, post-transition, by the Panamanians, and includes a study of the driving forces that led to privatization. We will conclude by looking at the results of the successful reform of the system, currently considered a primary model for other Latin American countries.