Effects Of Anthropogenic Heat Research Articles

Critical evaluation of the spatiotemporal behavior of UHI, through correlation analyses based on multi-city heterogeneous dataset

This study utilizes year-round temperature data observed in 15 cities around the United States (U.S.) to investigate the relationships between UHI and urban design attributes, and answer the following questions: (1) Whether and to what extent these relationships vary with the diurnal cycle and across seasons?, (2) What is the spatial extent within which UHI is affected by different urban variables?, and (3) Which climatic factors determine the correlations between UHI and urban variables? Our analysis revealed that while surface reflectance, vegetation and building height are more influential on winter UHI, the effect of anthropogenic heat and building density is independent of the season. Also, tree canopy cover, impervious area and built-up area were more dominant on nighttime UHI, and albedo, surface reflectance, vegetation and building height had stronger influence on daytime UHI. With regards to the spatial extent, while the effect of 3D urban variables and imperviousness was prominent in the immediate vicinity (250 m–1 km), the effect of vegetation, surface reflectance and anthropogenic factors extend to a larger surrounding area (4 km–8 km). Lastly, the relationships between UHI and urban variables were noted to be strongly driven by humidity in each location.

The Arrhenius Approach and the Effects of Anthropogenic Heat on the Temperature of the Earth´s Surface

The Arrhenius Approach and the Effects of Anthropogenic Heat on the Temperature of the Earth´s Surface

The Effect of Anthropogenic Heat and Moisture on Local Weather at Industrial Heat Islands: A Numerical Experiment

The current study addresses the role of heat and moisture emitted from anthropogenic sources on the local weather with the aid of numerical weather prediction (NWP). The heat and moisture emitted by industries to the atmosphere are considered main sources in this study. In order to understand the effect of heat and moisture on local weather, the study is conducted to capture the impact of heat with no moisture change. The results are compared against a control run case without perturbation and also against the case where both heat and moisture are perturbed with temperature as a single parameter. The Angul district in Odisha that houses over 4000 industries is considered our study region. The numerical simulations are performed using the mesoscale Weather Research and Forecasting (WRF) model for two rain events, namely a light rain case and a heavy rain case, with different physics options available in the WRF model. The WRF simulated maximum rainfall rate using various microphysics schemes are compared with the Tropical rainfall measuring mission (TRMM) observations for validation purposes. Our study shows that the WDM6 double moment microphysics scheme is better in capturing rain events. The TRMM-validated WRF simulation is considered a reference state of the atmosphere against which comparisons for the perturbed case are made. The surface temperature is perturbed by increasing it by 10 K near the industrial site and exponentially decreasing it with height up to the atmospheric boundary layer. A numerical experiment represents heating without addition of moisture by recalculating the relative humidity (RH) corresponding to the perturbed temperature. The perturbed temperature affects sensible heat (SH) and latent heat (LH) parameters in the numerical experiment. From the results of the numerical investigation, it is found that the near-surface rainfall rate increases locally in a reasonable manner with the addition of sensible heat to the atmosphere. A comparison against the case where moisture is added shows that enhanced rainfall is more sensitive to sensible and latent heat than sensible heat alone.

Spatio-temporal variations of surface temperatures of Ahmedabad city and its relationship with vegetation and urbanization parameters as indicators of surface temperatures

Land Surface Temperature (LST) has major importance in urban climatology, global climate change, and earth-atmosphere energy transfer. Relationship of vegetation and built-up parameters as indicators of LST has been investigated in the present study. The present study has been carried out to analyze the variations in rising in LST in the urban area than the neighboring rural area for three different seasons’ winter, summer and monsoon of the years from 2009 to 2013 using Moderate Resolution Imaging Spectroradiometer (MODIS) sensor data. Analysis of 8-day night-time LST data shows that significant surface urban heat island (SUHI) exists over the Ahmedabad study area. Mean annual SUHI intensity from 2009 to 2013 varies from 6.01 K to 6.56 K, and overall mean SUHI intensity has been found out to be 6.17 K. SUHIindex has been used to compare the SUHI intensity of different periods and different seasons. The relationship of LST with normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), road density (RD), normalized difference built-up index (NDBI) and percent impervious surface area (%ISA) has also been investigated in the present work. An inverse relationship has been observed between LST and vegetation indices (VIs) and it is season dependent. EVI has been used as a better vegetation parameter for SUHI studies than NDVI. %ISA has been reported to be a significant parameter for the analysis of SUHI effect and its relationship with LST has been found to be season independent. The relationship between %ISA and LST is similar for all three seasons with a consistent rising trend. A positive relationship has been observed between LST and NDBI especially for monsoon months. The trend of LST-NDBI relationship during different season is different, which indicates that the relationship between LST and NDBI is linear and is season dependent. It has been observed that soil and drier vegetation in rural areas show higher NDBI values. Hence NDBI cannot be used as a good indicator for SUHI studies. %ISA has been found to be a better parameter for SUHI studies compared to NDBI. Another parameter, RD, has been introduced in the present study to represent the extent of urbanization. A consistent positive relationship between RD and LST has been found for all the three study seasons of the entire study period, thus indicating seasonal independence of RD and LST relationship. Use of RD also considers the effect of anthropogenic heat, which is one of the main contributors to the SUHI effect, in addition to the effect of the impervious surfaces. Hence, RD is proposed as a suitable indicator for SUHI studies.

Model-Integration of Anthropogenic Heat for Improving Air Quality Forecasts over the Beijing Megacity

In air quality forecasting systems, failure to consider the considerably large anthropogenic heat emissions generated daily in the Beijing megacity by intensive human activities is one of the major causes of model failure. In this paper, we employ the nested air quality prediction model system coupled with the weather research and forecasting model and an urban canopy model to integrate anthropogenic heat emissions over Beijing into the modeling system and exhaustively evaluate their potential effects on air quality forecast by analyzing the wind field, boundary layer structure (height and atmospheric circulation), and surface and vertical distribution of pollutants. Consequently, the effects of anthropogenic heat on the boundary layer structure, greatly pronounced in urban areas, exhibited substantial variability at different levels depending on the time. The effects were evident during both daytime and night, but played a more prominent singular role in the night in the absence of solar short-wave radiation. Basically, anthropogenic heat acts not only by directly inducing the ascent of a warm air mass from the low parts of the atmosphere over urban areas to the top of the boundary layer, but also by indirectly driving wind convergence and inducing the descent of a cooled air mass from a high altitude to the boundary layer through a complex atmospheric circulation process. Incorporating anthropogenic heat emissions into the modeling system was effective in improving predictions by reducing the normalized mean bias by 20%–30% (for wind speed) and root mean square error by 361–558 m (for boundary layer height) and by 10–23 µg m–3 (for surface PM10), with a significant reduction in the underestimation of ozone concentration by approximately 20 ppb at urban sites. This paper is expected to provide new insights into the improvement of model accuracy for air quality forecasts over megacities.

Effects of anthropogenic heat on ozone air quality in a megacity

Anthropogenic heat released into the atmosphere in urban areas affects the characteristics/structures of boundary layer and local circulation and thus can affect local air quality. In this study, the effects of anthropogenic heat on ozone (O3) air quality in the Seoul metropolitan area, Republic of Korea, are examined using the Community Multiscale Air Quality (CMAQ) model coupled with the Weather Research and Forecasting (WRF) model. The release of anthropogenic heat is found to increase O3 concentration by 3.8 ppb in the urban area, and this effect is larger in the nighttime (5.3 ppb) than in the daytime (2.4 ppb). As stronger anthropogenic heat is released, the urban boundary layer becomes deeper and NOx concentration becomes lower due to the dilution. The decrease in NOx concentration causes the chemical loss of O3 by the reaction with NO to be reduced. In addition to the enhanced net chemical production of O3 in the deepened urban boundary layer, the strengthened urban-breeze circulation by anthropogenic heat contributes to an increase in O3 concentration in the urban area. The O3-rich air in the surroundings of Seoul, where biogenic volatile organic compound (BVOC) emissions are high and NOx emissions are low, is brought into the urban area by the urban breeze. Moreover, in the daytime, the advection of oxidant products of BVOCs by the urban breeze contributes to an enhanced chemical production of O3 in the urban area. Anthropogenic heat also modifies the sea/land-breeze circulations, which, in turn, is found to influence O3 concentration in the urban area.

A Study on the Effect of Anthropogenic Heat on the Temperature Distribution in the Urban Canopies

A Study on the Effect of Anthropogenic Heat on the Temperature Distribution in the Urban Canopies

The Effect of Anthropogenic Heat on Local Heat Island Intensity and the Performance of Air Conditioning Systems

Anthropogenic heat released from air conditioning systems is one of the most important factors contributing to the heat island in summer. A model to predicted heat island intensity is built. Using this model, a typical office building cluster is simulated, and the effect of heat released by air condition on outdoor thermal environment and heat island intensity is discussed. Furthermore, the reaction of heat island intensity rising on the performance of air conditioning systems is also investigated.

東京２３区を対象とした建物間気温への人工排熱影響に関する数値実験

東京２３区を対象とした建物間気温への人工排熱影響に関する数値実験