Comparative Study of Factors Contributing to Land Surface Temperature in High-Density Built Environments in Megacities Using Satellite Imagery

In this study, the root sources contributing to the urban heat island (UHI) effect between megacities, such as Hong Kong and Shenzhen, were integrated and compared using satellite remote sensing data. Classification and multilayer perceptron regression tree (CARTMLP) algorithms were used to classify land use. The radiative transfer equation method was applied to retrieve the land surface temperatures (LSTs) in the study area. Multiple linear regression analysis was applied to determine the relationship between land-use types and UHIs. The experimental results show a large area of relatively high temperature dispersed within Shenzhen, and comparatively small areas highly centralized in Hong Kong, with the retrieved LST in Hong Kong lower than that in Shenzhen. In addition, the surface temperature of large complex buildings decorated with high-albedo materials in Hong Kong was higher than in Shenzhen (e.g., Hong Kong International Airport, 25.12 °C; Shenzhen Bao’an International Airport, 23.38 °C), with artificial heat being an important contributor to these differences. These results also imply that high-albedo materials are sufficient to alleviate high temperatures. These findings are integrated to propose an organic combination strategy for reducing UHI effects in urban areas in megacities worldwide, such as Hong Kong and Shenzhen in China.

Artificial heat waves induce species-specific plastic responses on reproduction of two spider mite predators

Climate change models predict that the frequency, intensity and duration of heat waves will increase in the next decades. Heat waves can have profound impact on the reproduction of biocontrol agents ranging from postponing oviposition to manipulating offspring quantity via egg number and quality via egg size. Such species-specific responses of biocontrol agents to heat stress may also affect their success in controlling the target pest. Here, we evaluated the predation and reproductive performance of the two spider mite predators Phytoseiulus persimilis and Neoseiulus womersleyi exposed to simulated mild, moderate and extreme heat wave conditions over three days. Irrespective of heat wave conditions, all N. womersleyi females survived, whereas 12% of the P. persimilis females died. Both species responded to heat stress via plastic modifications resulting in increased predation rates and smaller egg sizes. Significantly more P. persimilis females postponed oviposition during the experimental phase than N. womersleyi. The deposited egg number of Phytoseiulus persimilis was not affected by heat wave conditions. On the contrary, the reproductive output of N. womersleyi was a function of temperature, i.e., the higher the temperature, the higher the number of deposited eggs. These findings indicate that P. persimilis is more heat sensitive in relation to reproduction than N. womersleyi. However, further investigations of heat wave effects on other fitness-related traits and their consequences at population level are needed to find out whether N. womersleyi is an alternative or supplement to P. persimilis as spider mite control agent under heat waves.

Radiative Flux of a Spectral Distribution at the Surface of a TPV Thermal Emitter Resulting from the Combustion of Biomass: Case of Palms Nut Shells

Thermo PhotoVoltaic (TPV) system convert into electrical energy the radiation emitted from an artificial heat source (i.e., solar or combustion) by the use of photovoltaic cells. In the last decade, TPV system has gained an increasing attention as cogeneration system for the distributed generation sector. Nevertheless, these systems are not fully developed and studied: several aspects need to be further investigated and completely understood. In this study, we modeled and investigated by performing numerical simulation on the feasibility of the TPV system exploiting waste heat energy during biomass combustion. To achieve this goal, we considered a TPV system in which we evaluated and analyzed the waste heat flux resulting from the combustion of the palm nuts shells as well as the corresponding temperature received at the surface of the TPV Thermal-emitter. Furthermore, we evaluated the heat intensity. Results obtained shows that the average temperature at the TPV absorber-emitter is around 1600k. Different variation of the net heat flux at the TPV absorber-emitter are observed for different position. The maximum heat intensity is around 15*1010 W.m-2.µm-1 for a wave length of 2000 nm. These results indicate that the model presented herein is therefore suitable for the design of the TPV system.

Numerical Investigation on the Urban Heat Island Effect by Using a Porous Media Model

The urban heat island (UHI) effect resulted from urbanization as well as industrialization has become a major environmental problem. UHI effect aggravates global warming and endangers human health. Thus, mitigating the UHI effect has become a primary task to address these challenges. This paper verifies the feasibility of a three-dimensional turbulent porous media model. Using this model, the authors simulate the urban canopy wind-heat environment. The temperature and flow field over a city with a concentric circular structure are presented. The impact of three factors (i.e., anthropogenic heat, ambient crosswind speed, and porosity in the central area) on turbulent flow and heat transfer in the central business district of a simplified city model with a concentric circular structure were analyzed. It is found that the three-dimensional turbulent porous media model is suitable for estimating the UHI effect. The UHI effect could be mitigated by reducing the artificial heat and improving the porosity of the central city area.

Pacific circulation response to eastern Arctic sea ice reduction in seasonal forecast simulations

Recent studies point to the sensitivity of mid-latitude winter climate to Arctic sea ice variability. However, there remain contradictory results in terms of character and timing of Northern Hemisphere large-scale circulation features to Arctic sea ice changes. This study assesses the impact of realistic late autumn eastern Arctic sea ice anomalies on atmospheric wintertime circulation at mid-latitudes, pointing to a hidden potential for seasonal predictability. ​Using a dynamical seasonal prediction system, an ensemble of seasonal forecast simulations of 23 historical winter seasons is run with reduced November sea ice cover in the Barents-Kara Seas, and is compared to the respective control seasonal hindcast simulations set. ​A non energy-conserving approach is adopted for achieving the desired sea ice loss, with artificial heat being added conditionally to the ocean surface heat fluxes so as to inhibit the formation of sea ice during November. Our results point to a robust atmospheric circulation response in the North Pacific sector, similar to previous findings on the multidecadal timescale. Specifically, an anticyclonic anomaly at upper and lower levels is identified over the eastern midlatitude North Pacific, leading to dry conditions over the North American southwest coast. The responses are related to a re-organization (weakening) of west-Pacific tropical convection and interactions with the tropical Hadley circulation. ​A possible interaction of the poleward-shifted Pacific eddy-driven jet stream and the Hadley cell is discussed​. ​The winter circulation response in the Euro-Atlantic sector is ephemeral in character and statistically significant in January only, corroborating previous findings of an intermittent and non-stationary Arctic sea ice-NAO link during boreal winter. These results ​aid our understanding of the seasonal impacts of reduced eastern Arctic sea ice on the midlatitude atmospheric circulation with implications for seasonal predictability in wintertime.

Requirements for the arrangement of poultry houses for keeping guinea fowl

This article discloses the requirements for the installation of poultry houses and indoor equipment for keeping guinea fowl. In the construction of poultry houses it is necessary to take into account the behavioral and physiological characteristics of guinea fowl on which their growth and development, productivity, feed consumption and disease resistance. For construction of a poultry house choose the elevated site or with a small slope that thaws and rain waters did not collect and did not stagnate. The size of the poultry house depends on the number of livestock in it, so it is recommended to place up to 5 heads per 1 m2 of floor area. The roof of the poultry house is made sloping. Litter is used in the premises for keeping guinea fowl: peat, straw, sawdust, litter thickness –10-15 cm. During the whole winter period the litter is not removed, only fresh is added regularly. If the litter is heavily soiled, the contaminated part is removed and a clean one is added. For winter keeping of guinea fowl the room is well warmed, without allowing in it humidity and formation of a mold. When keeping guinea fowl in the summer, it is recommended to equip them with a walking yard, fenced with wire mesh, around which bushes and trees are planted or canopies are made to protect the bird from direct sunlight. In winter, an artificial heat source is installed in the poultry house, for example, electric brooders, electric lamps with a metal shade-reflector located at a height of 15-20 cm from the floor. Seats for guinea fowl are made of chipped bars with rounded upper edges, which are installed on the opposite side of the windows in a horizontal form. Nests are set in the henhouse long before the laying hens begin to lay eggs, so that the guinea fowl have time to get used to them and lay eggs in the nests. Feeders are made like troughs, which prevents contamination and scattering of food. A turntable is mounted on the brackets on top of the feeder, it rotates around its axis and also prevents the feed from scattering. At the height of the feeder is made so that the edges of the sides were at the level of the back of the bird. It is better to use vacuum or nipple drinkers to water the guinea fowl, which provide them with fresh running water.

Life in the suburbs: artificial heat source selection for nocturnal thermoregulation in a diurnally active tropical lizard

The rapid expansion of urban environments invariably presents a novel series of pressures on wildlife due to changes in external environmental factors. In reptiles, any such changes in temperature are critical since thermoregulation is the key driver in the function of many physiological processes. How reptiles adapt to such changes may vary from those species that are impacted negatively to others that have the behavioural flexibility to exploit new conditions. In this paper we describe retreat site selection, movements and aspects of the thermal ecology of the African lizard Agama agama in urban environments of West Africa. In early evening lizards began movement from late-afternoon core activity areas and ascended the walls of houses for overnight retreats. A high proportion retreated to locations in groups under or on top of warm electrical panels. The thermal potential these panels offered was the attainment of body temperatures equal to or higher than the minimum preferred body temperature (PBT ≈ 36 ∘C in A. agama) and hence increased physiological performance. The lizards that took advantage of the heat sources travelled further each day to and from diurnal activity areas than individuals that spent the night high on walls but not next to heat panels. There were both potential costs (enhanced predation pressures) and benefits (impacts on thermal ecology, retreat site selection) of this behaviour for lizards living in urban environments.