Fighting energy poverty in a typical Peruvian rural house

This study evaluates a typical, informal construction in the Peruvian highlands of Cuzco, a site at an Equatorial latitude (13,5° S), approximately, 3.400 mamsl, with a subtropical highland climate (Köppen Cwb). Its aim is to compare low-cost passive retrofit strategies, applicable in cities and rural areas with similar climate, and validate a best choice. To carry out this study a dynamic energy simulation was performed, using the typical meteorological year (IWEC) provided by ASHRAE. The model was used to understand the effects of simple changes in the envelope configuration and the associated effect on infiltration, and their combination, on the indoor comfort and the energy performance of the building. The outcomes were displayed in a simple Energy-needs/transformation cost chart and a Pareto curve was selected, identifying an optimal subset of solutions. Adequate indoor conditions can be obtained with the implementation of only passive strategies, mainly empowering the thermal insulation of walls, roofs and windows using simple, low cost, local technologies, and the control of the heat transmission toward the soil: the energy poverty of the informal settlements of Cuzco can be fought with very simple initiatives, that require investments with a reasonably short return of investment.

M(3000)F2 and IRI-2012 model at an equatorial latitude in the African sector

We have used ionosonde data from Ouagadougou (Geo. Lat.12.40 N, Long. 358.50, Magnetic declination -5.1320) to study the morphology of M(3000)F2 and to investigate the performance of IRI-12 during 1991 and 1995, years of high and low solar activities respectively. Results show that M(3000)F2 exhibits diurnal and solar cycle characteristics with no distinctive monthly/seasonal features. The two peaks which characterize the diurnal M(3000)F2 during high solar activity (HSA) are reduced to just one (the sunrise peak) during low solar activity (LSA). The study also shows that IRI-12 gives good representations of the observed values of M(3000)F2 with high correlation coefficient, R ranging between 0.9 and 0.95 during LSA and 0.94 and 0.99 during HSA. The model gives its best performance in the months of April irrespective of the solar activity. It either under-estimates or over-estimates the observed values of M(3000)F2 during other months.

Modelling of solar thermal energy for household use in equatorial latitude by using the F-Chart model

The Andean Equatorial Region, due to its geographic location, shows great potential for using solar energy. Solar thermal energy is of interest in the residential sector in Ecuador and other Andean countries as a method to avoid fossilderived fuels consumption. However, previous learnings of the operation of solar water heating systems in other latitudes cannot be used in the conditions of Ecuador. Thus, the performance of the solar thermal energy systems in this geographic region deserves further study that consider typical high levels of cloudiness and fast climate oscillations. The objective of this work was to investigate the effect of the orientation of solar thermal plates on their energy efficiency and model the behaviour of these systems to predict their operation under Equatorial Andean climate conditions. For the F-Chart calibration different slopes angles were used, according to the typical roofs slopes in Cuenca, Ecuador. Results showed a monthly solar fraction, contributed by an evacuated tube collector is 26% higher than the flat plate collectors. The results also depict that, in the conditions of Cuenca, the greater solar water heating occurs when the collector is inclined 14° and facing towards the south. These findings can be used to predict the best operational conditions for using solar thermal energy collectors to produce hot water in the residential sector under equatorial highland altitude conditions.

Comparative Analysis of the Measured and Modeled Equatorial Thermospheric Wind Climatology

<p>The thermospheric winds play an important role in the vertical and horizontal couplings of the upper atmosphere by modulating neutral and plasma dynamics. A large variety of observation techniques and numerical as well as empirical models have been developed to understand the behavior of thermospheric winds. The Fabry-Perot interferometer (FPI) is a widely used ground- and satellite-based optical instrument for the thermospheric winds observations in the upper atmosphere. Due to solar contamination of the fainter airglow emission during the daytime, most of the ground-based interferometric wind measurements are limited to the nighttime period only. Despite these constraints, the Second‐generation, Optimized, Fabry‐Perot Doppler Imager (SOFDI) is designed for both daytime and nighttime measurements of thermospheric winds from OI 630‐nm emission and is currently operating at the Huancayo, Peru, near the geomagnetic equator. In this study, we present a comparative analysis of the observed SOFDI wind climatological data and several other modeled results including, but not limited to, Horizontal Wind Model 2014 (HWM-14), Coupled Thermosphere Ionosphere Plasmasphere Electrodynamics (CTIPe) model with and without implementing Prompt Penetration Electric Field (PPEF), Whole Atmosphere Model (WAM), SAMI3 model, and Magnetic mEridional NeuTrAl Thermospheric (MENTAT) model. We examine the relative performances of these models in the context of the direct-measured thermospheric winds. The day and nighttime modeled winds show an excellent agreement with the SOFDI wind data at the equatorial latitude, except for the daytime zonal winds. Further, this analysis gives a comprehensive picture of how well the measured winds provided by the SOFDI instrument and various models represent the features of the equatorial thermosphere. We also investigate and give an overview of the sources, drivers, effects, and possible mechanisms of the wind variability in the low-latitude thermosphere.</p>

Ionospheric Narrowband and Wideband HF Soundings for Communications Purposes: A Review

High Frequency (HF) communications through ionospheric reflection is a widely used technique specifically for maritime, aeronautical, and emergency services communication with remote areas due to economic and management reasons, and also as backup system. Although long distance radio links can be established beyond line-of-sight, the availability, the usable frequencies and the capacity of the channel depends on the state of the ionosphere. The main factors that affect the ionosphere are day-night, season, sunspot number, polar aurora and earth magnetic field. These effects impair the transmitted wave, which suffers attenuation, time and frequency dispersion. In order to increase the knowledge of this channel, the ionosphere has been sounded by means of narrowband and wideband waveforms by the research community all over the world in several research initiatives. This work intends to be a review of remarkable projects for vertical sounding with a world wide network and for oblique sounding for high latitude, mid latitude, and trans-equatorial latitude.

Western Pacific marginal basin plate tectonics: overview, questions, and insights from mantle structure

<p>The western Pacific marginal basins are a collage of plates and marginal seas that primarily formed in the Cenozoic and occupy the complex tectonic area between the converging major Eurasian, Indo-Australian and Pacific plates.  Strongly contrasting plate tectonic reconstructions continue to be proposed for this region.  Here we review current plate models, key questions, and highlight recent insights from mantle structure studies. </p><p>The Philippine Sea plate (PSP) is one of the largest marginal seas in the region.  The plate is currently moving WNW, in a similar orientation to the Pacific and Caroline plates.  Multiple studies show that PSP plate tectonics are key to unravelling the history of the region, for several reasons: (1) the PSP is far-travelled; paleomagnetism indicates relatively rapid (5.5 cm/yr) PSP northward motions since the Eocene from a near-equatorial latitude; (2) PSP tectonic histories imply interactions with many surrounding plates and regions, including the South China Sea (SCS), Taiwan, Japan, the western Pacific, and other smaller plates or fragments (i.e. Luzon or Celebes Sea); (3) the pre-subduction size of the PSP is not well-established because most of the plate is surrounded by subduction zones.  We review recent studies that attempt to ‘unsubduct’ the PSP from tomography and discuss their regional implications.</p><p>Another key but highly controversial topic is South China Sea (PSCS) formation and associated proto-South China Sea (PSCS) disappearance, if such a plate had existed.  The most popular proto-South China Sea plate model invokes southward subduction of the proto-South China Sea beneath NW Borneo during the Cenozoic.  Although southward PSCS subduction is most consistent with our current geological understanding, the regional mantle structure does not easily fit with this model; other scenarios may be possible.  In particular, it has not been straightforward for the southward PSCS model to explain the origin of sub-horizontal slabs under the present SCS at relatively shallow (500 to 800 km) depths.  We show an alternative ‘double-sided’ PSCS subduction model that produces testable hypotheses for future NW Borneo studies. </p><p>Finally, the Caroline Sea plate has an enigmatic history but is important for understanding the southern Marianas, Yap and Palau trenches.  We first review previous evidence for a ‘Caroline hotspot track’ and overlapping LIPs that traverse the northern Caroline plate.  We link these features to an imaged lower mantle plume and show their implications for Caroline-Pacific plate motions since the latest Eocene. </p>