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The various notions of urbanization, indicators of the urban climate, and air quality are described in this article. Urban air quality management and haphazard planning have an impact on climate change at the regional and global levels. The influence of urbanization, its trends, changes in land use patterns, and indicators of climate change are revised in sections of the literature review. Urban dynamics have an impact on microclimate, hence micro-meteorology and air quality are connected. The impact of changing land use patterns, thermal characteristics of surface materials, urban heat island (UHI) intensity, and emission sources that affect microclimate have all been discussed. Prediction models and their drawbacks, such as the effects of urban climate change, weather, and the dispersion of air pollution. A scenario on urban land use patterns, its effects on the climate, weather, and air quality, as well as a description of the relevant models, are presented in an in-depth review. [Display omitted] • Comprehensive Exploration of Urbanization and Climate. • Urban planning and development with urbanization, microclimate, and air quality. • Unpacking the Urban Heat Island Effect. • Models and their limits for urban climate change. [ABSTRACT FROM AUTHOR]

With increasing interest in urban meteorology and related services, the need to appropriately represent the urban environment in climate/weather models is rising. These regional weather/climate models typically use a km‐scale horizontal grid, which is insufficient to resolve the flow around buildings. Effects of the urban environment on the atmosphere above are represented through a bulk approach using the Urban Canopy Parametrization (UCP) schemes. Existing UCPs usually use the repeating canyon–roof representation that assumes homogeneous distribution of buildings within the grid box. It is commonly accepted that the assumption of homogeneity holds at km‐scale grid resolution but whether it also holds at sub‐km scale, where the regional models are increasingly approaching, is questionable. For this reason, among others, the resolution ranges from a few hundred metres to tens of metres (i.e. building‐resolving scales) is termed the building grey zone in the existing literature. This work shows that the assumption of homogeneity indeed does not hold at the building grey zone for the city‐state Singapore. To understand the possible influences of the use of UCPs at scales from the building grey zone to the conventional mesoscale, we use an urban‐grid method that allows us to estimate the parametrized fluxes from a typical UCP at varying resolutions over the urban landcover while keeping the same atmospheric model grid. Numerical results show that different urban‐grid resolutions yield variations in the near‐surface temperature and wind to a maximum of 0.5 K and 1 m·s−1. Their impact on the boundary‐layer parameters is found to be limited. Although these near‐surface variations are small, they are comparable to the near‐surface scaling variables and are thus physically significant. [ABSTRACT FROM AUTHOR]

Here we present, for the first time, a glossary of biometeorological terms. The glossary aims to address the need for a reliable source of biometeorological definitions, thereby facilitating communication and mutual understanding in this rapidly expanding field. A total of 171 terms are defined, with reference to 234 citations. It is anticipated that the glossary will be revisited in coming years, updating terms and adding new terms, as appropriate. The glossary is intended to provide a useful resource to the biometeorology community, and to this end, readers are encouraged to contact the lead author to suggest additional terms for inclusion in later versions of the glossary as a result of new and emerging developments in the field.

The role of advection of heat and momentum on the evolution of near-surface temperature and wind is evaluated in urban-aware simulations over Houston, Texas, under dry conditions on a light-wind day. Two sets of experiments, each consisting of four simulations using different planetary boundary layer (PBL) schemes, were conducted over 48 h using the default urban scheme (BULK) and the single-layer urban canopy model (SLUCM) available within the Weather Research and Forecasting Model. We focus on understanding and quantifying the role played by temperature and momentum advection, particularly on the windward and leeward sides of the city. Previous studies have largely ignored any quantitative analysis of impacts from the advection of momentum over an urban area. The horizontal advection of temperature was found to be more important in the BULK because of the larger surface temperature gradient caused by warmer surface temperatures over urban areas than in the SLUCM. An analysis of the momentum budget shows that horizontal advection of zonal and meridional momentum plays a prominent role during the period of peak near-surface winds and that this effect is more pronounced in the windward side of the city. The local tendency in peak winds in the leeward side lags that in the windward side by about 1–2 h, similar to the lag found in horizontal momentum advection. The sensitivity of the results to different urban and PBL schemes was explored. The results imply that representation and influence of land-use patterns via sophisticated urban parameterizations generate locally driven winds that best resemble observations. [ABSTRACT FROM AUTHOR]

Cities are transforming the surfaces that are initially natural into coated surfaces, resulting in climate change, destruction of green areas, air pollution, and floods, etc.,. This study was carried out in order to minimize the impact of urbanization on the natural environment and the impact of climate change on the urban environment of Eskişehir, which has experienced in Turkey in the early years (1930). In the study, meteorological station data of the city center (Eskişehir Regional Meteorology Station) and its vicinity (Anadolu University Meteorology Station and Airport Meteorology Station) and the map of Metropolitan Municipality were used. Field studies were also carried out on the field. Bioclimatic comfort values were calculated by Rayman software and evaluated according to Pet index. Arcgıs 10.1 version was used in the analysis and maps of the field. The climate, thermal comfort and air quality analyzes were made and mapped in the study. According to the results, urban heat islands, excessive air pollution and areas where the wind speed is very slow have been determined. It was observed that these problems were caused by anthropogenic factors such as dense and high-rise areas, excessive asphalt and concretization, traffic density, and destruction of green areas. Design proposals for sustainable ecological urbanization were developed and urban planning was made. It is not only thought that the designs and decisions made will be a solution to the problems of today, but it will also cause the results to slow down or even stop the change in climate elements. [ABSTRACT FROM AUTHOR]

Mesoscale meteorology models, such as the Weather Research and Forecasting (WRF) model, typically use land use categorization data to specify surface characteristics by grid cells. In commonly used land use schemes, such as the 24‐class U.S. Geological Survey land use classification system or the Moderate Resolution Imaging Spectroradiometer landcover product, cities are placed in single urban categories that are characterized by a high roughness length. Monin‐Obunkov similarity theory is commonly used to simulate boundary layer dynamics based on surface energy and momentum fluxes which resulted in an overprediction of wind speed in weather forecasts for urban areas. It is thus crucial to include the momentum drag effects of the buildings, including walls and roofs, in the prediction models. The WRF model contains several momentum flux parameterizations, including the single‐layer urban canopy model, building effect parameterization, and building energy model. The building energy model and building effect parameterization schemes are limited to the Mellor‐Yamada‐Janjic or BouLac planetary boundary layer models and are computationally costly. In this study, a realistic multilayer urban approach is introduced into the Asymmetric Convective Model version 2 planetary boundary layer component of the WRF model. Sensitivity tests are applied to a range of urban morphological parameters in idealized simulations, and the impact of building morphology on atmospheric conditions is examined. The modified Asymmetric Convective Model version 2 is implemented in two real cases in the forecast mode, resulting in significant improvements in wind speed prediction. Key Points: The momentum drag effect is introduced into the ACM2 model to account for the momentum deficit caused by urban morphologyUrban canopy theory is strengthened, and its effects on urban areas are analyzed in idealized simulationsImprovements in wind speed prediction, which is essential for air quality assessment over urban areas, are demonstrated in a real case study [ABSTRACT FROM AUTHOR]

Meteorology and air quality are key aspects for city life and urban metabolism. Both aspects build upon urban and natural processes, involve stocks and flows of heat and pollution, with in the end consequences for stocks and flows concerning other urban entities and processes such as human outdoor activities, leisure, transport modes, as well as for urban design and planning. During hot summer days cities experience an urban heat island effect mainly at the start of the evening and at night. As a result inhabitants might be subject to a reduced human thermal comfort. Hot summer days often also coincide with relatively poor air quality conditions. Both short-term effects are known to increase the mortality rates, and it is challenging to distinguish their impacts on health effects. Moreover, climate change scenarios indicate an enhancement of future heat wave frequency and intensity and a further deterioration of human thermal comfort. These issues raise the need and the urgency for city adaptation, but an integrated method for the assessment is still missing. Effective city adaptation is hampered by the complexity of the urban climate (induced by both meteorology and urban morphological characteristics) and its potential health risks, combined with the complex spatial interaction of stakeholders and economical functions. To warn the general public, and to effectively perform urban planning interventions, straightforward environmental indicators are required. Indicators have been developed for the individual aspects before, but indices that combine both air quality and urban heat are rather scarce ( Rainham and Smoyer-Tomic, 2003 ). This study develops a novel metric that combines the impact of thermal comfort and air quality by accounting for the relative health risk for both aspects. A straightforward quantification method for this metric has been developed to provide an objective, rational assessment. The application of this new Urban Climate assessment tool is then applied to a case study for a heat wave in the Northwestern Europe, and applied for a sample intervention in the city center of Ghent (Belgium). [ABSTRACT FROM AUTHOR]

A bibliometric analysis based on the Science Citation Index-Expanded (SCI-Expanded) database from the Web of Science was performed to review urban heat island (UHI) research from 1991 to 2015 and statistically assess its developments, trends, and directions. In total, 1822 papers published in 352 journals over the past 25 years were analyzed for scientific output; citations; subject categories; major journals; outstanding keywords; and leading countries, institutions, authors, and research collaborations. The number of UHI-related publications has continuously increased since 1991. Meteorology atmospheric sciences, environmental sciences, and construction building technology were the three most frequent subject categories. Building and Environment, International Journal of Climatology, and Theoretical and Applied Climatology were the three most popular publishing journals. The USA and China were the two leading countries in UHI research, contributing 49.56% of the total articles. Chinese Academy of Science, Arizona State University, and China Meteorological Administration published the most UHI articles. Weng QH and Santamouris M were the two most prolific authors. Author keywords were classified into four major groups: (1) research methods and indicators, e.g., remote sensing, field measurement, and models; (2) generation factors, e.g., impervious urban surfaces, urban geometry, waste heat, vegetation, and pollutants; (3) environmental effects, e.g., urban climate, heat wave, ecology, and pollution; and (4) mitigation and adaption strategies, e.g., roof technology cooling, reflective cooling, vegetation cooling, and urban geometry cooling. A comparative analysis of popular issues revealed that UHI determination (intensity, heat source, supporting techniques) remains the central topic, whereas UHI impacts and mitigation strategies are becoming the popular issues that will receive increasing scientific attention in the future. Modeling will continue to be the leading research method, and remote sensing will be used more widely. Additionally, a combination of remote sensing and field measurements with models is expected. [ABSTRACT FROM AUTHOR]

Background: There is strong association between childhood rotavirus, diarrhoea, climate factors and malnutrition. Conversely, a significant nutritional transition (reduced under-nutrition) with a concurrent increasing trend of rotavirus infection in last decade was also observed among under 5 children, especially in developing countries including Bangladesh. Considering the pathophysiology of rotavirus, there might be an interaction of this nutrition transition which plays a pivotal role in increasing rotavirus infection in addition to climate and other man-made factors in urban areas such as Dhaka, Bangladesh. Methods: Relevant monthly data from 1993–2012 were extracted from the archive of the Diarrhoeal Disease Surveillance System of icddr, b and linked with data collected from the Dhaka station of the Bangladesh Meteorological Department (mean temperature, rainfall, sea level pressure and humidity). Seasonal autoregressive integrated moving average time series models were deployed to determine the association between the monthly proportion of rotavirus infection and underweight, stunting and wasting adjusting for climate, socio-demographic and sanitation factors. Finding: The proportion of rotavirus cases among all causes diarrhoea increased from 20% in 1993 to 43% in 2012 (Chi squared for trend p = 0.010). In contrast, underweight, stunting and wasting decreased from 59%-29% (p<0.001); 53%-21% (p<0.001) and 32%-22% (p<0.001) respectively over the same period. Mean ambient temperature increased from 25.76°C-26.62°C (p = 0.07); mean rainfall, sea level pressure and mean humidity decreased from 234.92–111.75 mm (p = 0.5), 1008.30–1006.61 mm of hg (p = 0.02) and 76.63%-70.26% (p<0.001), respectively. In the adjusted model, a decrease in monthly proportion of underweight [coef.: -0.189 (95% CI:-0.376, -0.003)] and wasting [-0.265 (-0.455, -0.075)] were significantly and inversely associated with rotavirus infection. However, an inverse but insignificant association was observed for stunting [-0.070 (-0.249, 0.109)]. Interpretation: The reduction of acute childhood malnutrition is significantly associated with increasing rotavirus diarrhoea among under-5 children. Thus mass vaccination in addition to interventions directed at man-made modifiable predictors for prevention and control is warranted. [ABSTRACT FROM AUTHOR]

Cities are home to the majority of humanity. Therefore, understanding the mechanisms that control urban climates has substantial societal importance to a variety of sectors, including public health and energy management. In this study, data from an urban sensor network (25 stations) and moderate-resolution remote sensing were used to explore how spatial variation in near-surface air temperature Ta, vapor pressure deficit (VPD), and land surface temperature (LST) depend on local variations in urban land use, both diurnally and seasonally, in the Boston, Massachusetts, metropolitan area. Positive correlations were observed between the amount of local impervious surface area (ISA) and both Ta and VPD. Heat-island effects peaked during the growing-season nighttime, when mean Ta and VPD increased by up to 0.02%@176;C and 0.008 kPa, respectively, per unit ISA. Air temperature and VPD were strongly coupled, but their relationship exhibited significant diurnal hysteresis during the growing season, with changes in VPD generally preceding changes in Ta. Over 79% of the urban-rural difference in VPD was explained by differences in near-surface atmospheric water content, which the authors attribute to reduced evapotranspiration from lower canopy cover in Boston's urban core. Changes in daytime heat-island intensity were mediated by seasonal feedbacks between vegetation transpiration and VPD forcing. Differences between LST and Ta showed weaker coupling in highly urbanized areas than in rural areas, with summertime surface-urban-heat-island intensity (based on LST) being up to 14°C higher than corresponding urban-rural differences in Ta. [ABSTRACT FROM AUTHOR]

The goal of this study is to analyze the impacts of urban heat-island control, via increased surface albedo, on regional and urban meteorology, emissions, and ozone air quality over a range of summer conditions in California. The ozone air-quality impacts of heat-island control are then converted into precursor-emission equivalents. Linked atmospheric models used in this effort show that significant cooling of the urban canopy and boundary layers can be achieved, particularly during the daytime, but that warming can also occur. The air-quality improvements are significant where surface albedo is increased. Downwind of modified areas, the air-quality impacts can be positive or negative depending on meteorological conditions affecting the formation, transport, removal, and mixing of ozone and its precursors. Overall, and accounting for both positive and negative impacts of increased urban albedo, the models show beneficial net effects for California. The results do not account for additional benefits such as reduced cooling energy use and associated reductions in emissions from point sources, or the potential negative impacts on heating energy use in winter. These have been addressed elsewhere. This paper is a summary of results from a study and detailed report (Taha, 2013a) that can be accessed at http://www.energy.ca.gov/2013publications/CEC-500-2013-061/CEC-500-2013-061.pdf . [ABSTRACT FROM AUTHOR]

The cities of Ljubljana, Trieste and Zagreb are proximate in terms of distance but differ in terms of geographical and climatic conditions. Continuous meteorological measurements in these cities began in the mid-19th century. The 100-year trends of changes in mean annual and seasonal air temperatures for these cities are presented here, evaluating the differences between them which result from their different geographical and climatic positions. Differences in trends between Ljubljana and Zagreb that result from different measurement histories and the impact of urban climate are also presented: the impact of city growth on air temperatures in Ljubljana after 1950 was not completely eliminated in the process of data homogenization. The lowest air warming trends occur in the maritime climate of Trieste (mean annual air temperature: + 0.8 °C × 100 yr−1), where measurements were continuously performed in the densely built-up section of the city. The strongest trends occur in Ljubljana, mainly due to city growth (mean annual air temperature: + 1.1 °C × 100 yr−1). Comparing the linear trends in Zagreb-Grič and in Ljubljana, the impact of Ljubljana's urban heat island on the 100-year warming trend was assessed at about 0.2 °C, at 0.3-0.4 °C for the trend after 1950, and if non-homogenized data are used, at about 0.5 °C. [ABSTRACT FROM AUTHOR]

Climatic regionalization of Serbia was performed in the paper on the basis of data on air temperature from 23 meteorological stations and using cluster analysis. Applying Mann-Kendall test and Sen's slope estimates, temperature linear trends were investigated within each of the clusters, but also at each station individually. It has been shown that a positive linear trend is present in practically entire territory of Serbia and that it is very strong in Belgrade. Differences in air temperature between Belgrade and the cluster in which it is located were examined on an annual basis. [ABSTRACT FROM AUTHOR]

Cities represent thermal load areas compared with their surrounding environments. Due to climate change, summer heat events will increase. Therefore, mitigation and adaptation are needed. In this study, meteorological measurements in various local climate zones were performed to demonstrate the influence of evaporation surfaces and other factors on thermal comfort, as determined by the physiologically equivalent temperature (PET). Furthermore, a quantification of the thermal effects of several adaptation measures and varying meteorological parameters was made using model simulations (ENVI-met) in an inner-city neighborhood (Oberhausen, Germany). The results show that the most effective adaptation measure was increased wind speed (maximal 15 K PET reduction). Moreover, vegetation areas show greater PET reductions by the combination of shading and evapotranspiration than water surfaces. The creation of park areas with sufficient water supply and tall, isolated, shade-providing trees that allow for adequate ventilation can be recommended for planning. [ABSTRACT FROM AUTHOR]

This paper reviews the long tradition of city-scale climatological and meteorological applications prior to the emergence in the 1990s of early work on the urban/global climate change interface. It shows how ‘valuing and seeing the urban’ came to be achieved within modern scientific meteorology and how in a limited but significant set of cases that science has contributed to urban practice. The paper traces the evolution of urban climatology since 1950 as a distinct research field within physical geography and meteorology, and its transition from observational monographs to process modelling; reviews the precedents, successful or otherwise, of knowledge transfer from science into public action through climatically aware regulation or design of urban environment; and notes the neglect of these precedents in contemporary climate change discourse—a serious omission. [ABSTRACT FROM PUBLISHER]

This paper addresses the methodological concerns in quantifying urban heat island (UHI) intensity in Hong Kong SAR, China. Although the urban heat island in Hong Kong has been widely investigated, there is no consensus on the most appropriate fixed point meteorological sites to be used to calculate heat island intensity. This study utilized the Local Climate Zones landscape classification system to classify 17 weather stations from the Hong Kong Observatory's extensive fixed point meteorological observation network. According to the classification results, the meteorological site located at the Hong Kong Observatory Headquarters is the representative urban weather station in Hong Kong, whereas sites located at Tsak Yue Wu and Ta Kwu Ling are appropriate rural or nonurbanized counterparts. These choices were validated and supported quantitatively through comparison of long-term annual and diurnal UHI intensities with rural stations used in previous studies. Results indicate that the rural stations used in previous studies are not representative, and thus, the past UHI intensities calculated for Hong Kong may have been underestimated. [ABSTRACT FROM AUTHOR]

The utility of aggregating data from near-surface meteorological networks for initiating dispersion models is examined by using data from the 'WeatherBug' network that is operated by Earth Networks, Inc. WeatherBug instruments are typically mounted 2-3 m above the eaves of buildings and thus are more representative of the immediate surroundings than of conditions over the broader area. This study focuses on subnetworks of WeatherBug sites that are within circles of varying radius about selected stations of the DCNet program. DCNet is a Washington, D.C., research program of the NOAA Air Resources Laboratory. The aggregation of data within varying-sized circles of 3-10-km radius yields average velocities and velocity-component standard deviations that are largely independent of the number of stations reporting-provided that number exceeds about 10. Given this finding, variances of wind components are aggregated from arrays of WeatherBug stations within a 5-km radius of selected central DCNet locations, with on average 11 WeatherBug stations per array. The total variance of wind components from the surface (WeatherBug) subnetworks is taken to be the sum of two parts: the temporal variance is the average of the conventional wind-component variances at each site and the spatial variance is based on the velocity-component averages of the individual sites. These two variances (and the standard deviations derived from them) are found to be similar. Moreover, the total wind-component variance is comparable to that observed at the DCNet reference stations. The near-surface rooftop wind velocities are about 35%% of the magnitudes of the DCNet measurements. Limited additional data indicate that these results can be extended to New York City. [ABSTRACT FROM AUTHOR]

Abstract: A high resolution urban thermal sharpener (HUTS) was developed that increases the resolution of thermal infrared (TIR) data to that of visible and near infrared (VNIR) data by fitting the relationship between radiometric surface temperature, normalized difference vegetation index (NDVI) and surface albedo (α). HUTS was applied to TIR data aggregated to 90m to represent a satellite acquired dataset and validated against the measured 10m data from an aircraft over San Juan, Puerto Rico. HUTS sharpening reduced the root mean square error of surface temperature at the high resolution by 17% compared to no sharpening and outperformed other sharpening methods. HUTS is proposed as a useful tool to study urban meteorology and climatology at the microscale using ASTER satellite data. [Copyright &y& Elsevier]

A single-layered square prism urban canopy (SPUC) scheme for the Japan Meteorological Agency nonhydrostatic model (NHM) was developed. This scheme considers the urban canopy layer with square prism--shaped buildings. The basic concept of this scheme is similar to those of the conventional energy balance models for an urban canyon structure. The scheme presented here differs slightly from them in its representation of the bulk resistance circuit and some treatments of radiation processes, however, as well as by considering the water reservoir on building surfaces. A comparison between the SPUC scheme and the existing slab scheme of the NHM was made on summer days in the Tokyo metropolitan area. The SPUC run more accurately reproduced the expected behavior of the urban canopy effect than did the slab run. The effective albedo was smaller in the SPUC run than in the slab run (the upward shortwave radiation of the SPUC run was smaller than that of the slab run). The forecast heat fluxes in the SPUC run, however, showed worse performances. Adequate parameter settings (especially concerning latent heat fluxes) are needed in the SPUC run. The mean bias errors of the surface air temperature during nighttime were less negative and slightly improved in the SPUC run than in the slab run. [ABSTRACT FROM AUTHOR]

Urban canopy parameterizations (UCPs) are necessary in mesoscale modelling to take into account the effects of buildings on wind and turbulent structures. This study is focused on the dynamical part of UCPs. The main objective is twofold: first, computing important UCP input parameters (turbulent length scales and the sectional drag coefficient) by means of Reynolds-averaged Navier-Stokes (RANS) simulations of turbulent flow; and second, comparing UCP variables with spatially-averaged properties obtained from RANS simulations for the same configurations. The results show the importance of using a suitable parameterization of the drag force for different packing densities. An urban canopy parameterization that is a compromise between simplicity and accuracy is proposed. This scheme accounts for the variation of drag coefficients with packing densities, and has a parameterization of turbulent length scales. The technique adopted ensures that, at least for the simple configurations studied, the urban canopy parameterization gives values of spatially-averaged variables similar to those computed from a more complex simulation, such as RANS that resolves explicitly the flow around buildings. [ABSTRACT FROM AUTHOR]

This study proposes a method for estimating the canopy-layer net urban heat island (UHI) in regions with complex terrain that lack preurban observations. The approach is based on a linear relationship between the urban-rural temperature difference (Δ T u− r), measured via screen-level air temperature, and the population of the city, which was found to have the highest correlation with observations. The linear relation is extrapolated to zero population to yield the desired preurban value. The difference between the zero population Δ T u− r and the current one is proposed to represent the net UHI. Given the uncertainties of the population method, the relatively short time period of the temperature record, and possible inhomogeneity in the data, the results should be regarded as a first-order approximation of the net UHI contribution. The UHI was evaluated for an arid city, Beer Sheba, Israel, for the minimum and maximum air temperatures for the summer and the winter. The study region resembles the combined effect of complex terrain (i.e., the concave topography of the city in contrast with the plateau landscape surrounding it), the UHI, and the regional warming trend. The study assumes that the regional warming does not affect the Δ T u− r. The concave topography of the city dominates over the UHI contribution during nighttime, resulting in an average lower minimum temperature in the city relative to the rural area. This difference has decreased considerably during the study period and has even reversed for the summer nights toward the end of the period. The estimated net UHI contribution in Beer Sheba varies between +0.8° and +3.1°C, with the highest values during the night hours. The high positive UHI during the night is in line with previous studies. The positive UHI in the summer implies further aggravation of heat stress beyond that occurring, and that predicted to increase, over the region. [ABSTRACT FROM AUTHOR]

The article focuses on studies of urban climates and climatologists who study them. Topics include characterizations of the urban climate by urban climatologists, the opinions of urban climatologists on bad weather, and their assessment of the phenomenon of "global change" in the climate in the specific context of the city.

This study attempted to assess a bioclimate index and the occurrence of an urban heat island in the city of Campina Grande, northeastern Brazil, using data taken from mobile measurements and Automatic Weather Stations (AWS). The climate data were obtained during two representative months, one for the dry season (November 2005) and one for the rainy season (June 2006) at seven points in an urban area. Ten-minute air temperatures recorded by an AWS installed in urban areas were compared to those from a similar station located in a suburban area to assess the urban heat island (UHI). The data were collected using a 23X data logger (Campbell Scientific, Inc.) programmed for collecting data every second. The thermal discomfort level was analyzed by Thom’s discomfort index (DI), and an analysis of variance was applied for assessing if there was any statistically significant difference at the 1% and 5% significance level of thermal comfort among points. Mann–Kendall statistical test was used for identifying possibly significant trends in a time series for air temperature, relative humidity, and class A pan evaporation for the city of Campina Grande. The present study found UHI intensities of 1.48°C and − 0.7°C for the months taken as representative of the dry and rainy seasons, respectively. Summer in the city has partially comfortable conditions while the winter is fully comfortable. There are significant changes in DI hourly values between seasons. Only during the rainy season did all points of the city have a comfortable condition until 8:19 h, at which time they become partially comfortable for the rest of the day. Results indicated that there was a 1.5°C increase in air temperature and a 7.2% reduction in relative humidity throughout the analyzed time series. The DI also showed a statistically significant increasing trend (Mann–Kendall test, p < 0.01) for the dry and rainy seasons and annual period of approximately 1°C in the last 41 years in the city of Campina Grande. [ABSTRACT FROM AUTHOR]

Abstract: A modelling study with the on-line coupled Eulerian chemical-weather model WRF/Chem for the Southern Italian region around Cosenza (Calabria) was conducted to identify the influences of synoptic scale meteorology, local scale wind systems and local emissions on ozone concentrations in this orographically complex region. Four periods of 5–7 days were chosen, one from each season, which had wind pattern characteristics representative of typical local climatological conditions, in order to study the local versus non-local impacts on ozone transport and formation. To account for the complex terrain, the horizontal resolution of the smallest modelling domain was 3 km. Model results were compared with measurements to demonstrate the capability of the model to reproduce ozone concentrations in the region. The comparison was favourable with a mean bias of −1.1 ppb. The importance of local emissions on ozone formation and destruction was identified with the use of three different emission scenarios. Generally the influence of regional emissions on the average ozone concentration was small. However during periods when mountain-sea wind systems were well developed and synoptic scale winds were weak, the influence of local emissions from the urban area was at its greatest. The maximum influence of local emissions on ozone concentrations was 18 ppb. [Copyright &y& Elsevier]

The aim of this paper is to determine how an atmosphere with enhanced mean-state baroclinity can support weaker baroclinic wave activity than an atmosphere with weak mean-state baroclinity. As a case study, a Last Glacial Maximum (LGM) model simulation previously documented to have reduced baroclinic storm activity, relative to the modern-day climate (simulated by the same model), despite having an enhanced midlatitude temperature gradient, is considered. Several candidate mechanisms are evaluated to explain this apparent paradox. A linear stability analysis is first performed on the jet in the modern-day and the LGM simulation; the latter has relatively strong barotropic velocity shear. It was found that the LGM mean state is more unstable to baroclinic disturbances than the modern-day mean state, although the three-dimensional jet structure does stabilize the LGM jet relative to the Eady growth rate. Next, feature tracking was used to assess the storm track seeding and temporal growth of disturbances. It was found that the reduction in LGM eddy activity, relative to the modern-day eddy activity, is due to the smaller magnitude of the upper-level storms entering the North Atlantic domain in the LGM. Although the LGM storms do grow more rapidly in the North Atlantic than their modern-day counterparts, the storminess in the LGM is reduced because storms seeding the region of enhanced baroclinity are weaker. [ABSTRACT FROM AUTHOR]

Abstract: Thermal infrared (TIR) remote sensing techniques have been applied in urban climate and environmental studies, mainly for analyzing land surface temperature (LST) patterns and its relationship with surface characteristics, assessing urban heat island (UHI), and relating LSTs with surface energy fluxes to characterize landscape properties, patterns, and processes. This paper examines current practices, problems, and prospects in this particular field of study. The emphasis is placed in the summarization of methods, techniques, and applications of remotely sensed TIR data used in urban studies. In addition, some future research directions are outlined. This literature review suggests that the majority of previous research have focused on LST patterns and their relationships with urban surface biophysical characteristics, especially with vegetation indices and land use/cover types. Less attention has been paid to the derivation of UHI parameters from LST data and to the use of remote sensing techniques to estimate surface energy fluxes. Major recent advances include application of sub-pixel quantitative surface descriptors in examining LST patterns and dynamics, derivation of key UHI parameters based on parametric and non-parametric models, and integration of remotely sensed variables with in situ meteorological data for urban surface energy modeling. More research is needed in order to define better “urban surface” from the remote sensing viewpoint, to examine measurement and modeling scales, and to differentiate modeled and measured fluxes. [Copyright &y& Elsevier]

This study evaluates data from Aksaray, a medium sized urban city, and Cihanbeyli, a small town in Turkey, in order to show the effects of urbanization on water vapour pressure. Data taken at 07:00, 14:00 and 21:00 h and daily means were analyzed to identify the daily changes in water vapour pressure and temperatures. In Aksaray, positive urban heat island values were observed in all months except during afternoon hours. At all observation times during winter, weak water vapour pressure differences were recorded. During summer, on the other hand, positive water vapour differences were seen during afternoon and evening hours. A more humid city at afternoon hours is not typical of other mid-latitude countries. This is thought to be mainly related to the semi-arid climatic conditions in the area. Water vapour differences were seen to have a decreasing trend except during afternoon hours. As for temperature differences, an increase was seen during morning and evening hours, while a decrease was seen during afternoon hours and in daily means. A new trend was observed to start after the 1980s in both sets of data, which coincides with rapid population growth in Aksaray. Negative correlations were seen between water vapour pressure and temperature differences. No increase in water vapour pressure due to urbanization was observed in Aksaray. The decreasing evapotranspiration and the urban geometry appear to be the most influential factors in determining the water vapour pressure in Aksaray. [ABSTRACT FROM AUTHOR]

The use of high resolution 3D urban raster and vector databases in urban climatology is presented. It applies two different methods to the calculation of continuous sky view factors (SVF), compares their values and considers their usefulness and limitations in urban climate studies. It shows and evaluates the relationship between urban geometry, quantified by SVF, and intra-urban nocturnal temperature variations using areal means in the whole urban area of Szeged, a city located in southeast Hungary. Results from the vector and raster models shows similar SVF values ( r 2 = 0.9827). The usefulness of using areal means in SVF-temperature relations is confirmed. The vector and the raster approaches to the derivation of areal means of SVF are both shown to be powerful tools to obtain a general picture of the geometrical conditions of an urban environment. [ABSTRACT FROM AUTHOR]

A mesoscale meteorological model containing a detailed land surface model is used to assess the contribution of urban heating to the temperature record of the national recording station of Belgium in Uccle, near Brussels. The Advanced Regional Prediction System (ARPS) was applied over a domain of 60 km × 60 km with a horizontal resolution of 1 km. Four meteorological episodes were selected, and, for each of these, the model was integrated using two different land cover situations. The first consisted of a detailed reconstruction of the early nineteenth-century setting of Brussels and its wide surroundings, while the second corresponded to the present-day land cover. Since the nineteenth century, when the recording station of Uccle was established, a major land cover change from an agricultural area to a built surface has taken place. The temperature difference between the simulations at the site of Uccle was assumed to represent the urban effect on the site since the beginning of recording. The urban heat island (UHI) of Brussels was found to have a significant impact on the temperature record in Uccle. The urban–rural temperature difference was found to build up during the evening, gradually decreasing during the night and becoming zero during the day. By analyzing the surface energy balance it was revealed that the UHI is mainly caused by a greater storage of energy in the urban fabric during the day and a release of this heat in the evening. The UHI had a significant average impact on the Uccle temperature record during two of the four selected weather situations. The effect amounted to 0.77°C in a cloudy weather situation with westerly winds and to 1.13°C in a clear and calm weather situation. [ABSTRACT FROM AUTHOR]

In a companion paper, the authors presented a formulation and evaluation of an urban parameterization designed to represent the urban energy balance in the Community Land Model. Here the robustness of the model is tested through sensitivity studies and the model’s ability to simulate urban heat islands in different environments is evaluated. Findings show that heat storage and sensible heat flux are most sensitive to uncertainties in the input parameters within the atmospheric and surface conditions considered here. The sensitivity studies suggest that attention should be paid not only to characterizing accurately the structure of the urban area (e.g., height-to-width ratio) but also to ensuring that the input data reflect the thermal admittance properties of each of the city surfaces. Simulations of the urban heat island show that the urban model is able to capture typical observed characteristics of urban climates qualitatively. In particular, the model produces a significant heat island that increases with height-to-width ratio. In urban areas, daily minimum temperatures increase more than daily maximum temperatures, resulting in a reduced diurnal temperature range relative to equivalent rural environments. The magnitude and timing of the heat island vary tremendously depending on the prevailing meteorological conditions and the characteristics of surrounding rural environments. The model also correctly increases the Bowen ratio and canopy air temperatures of urban systems as impervious fraction increases. In general, these findings are in agreement with those observed for real urban ecosystems. Thus, the model appears to be a useful tool for examining the nature of the urban climate within the framework of global climate models. [ABSTRACT FROM AUTHOR]

This article examines the perception of climate change, in relation to 21 other socioeconomic and environmental problems, on the part of 132 respondents to a survey conducted in the city of Nairobi, Kenya. Factor analysis, used to condense these interrelated problems into a few dimensions, identified two overriding threats: the first being to socioeconomic security, and the second to the physical environment. Threats to socioeconomic security explained 76.6% of the variance in the rating of environmental and socioeconomic problems facing Nairobi, with very high factor loadings from corruption, unemployment, crime, street children, garbage, transport, poverty, pollution of Nairobi River, HIV/AIDS and immorality/promiscuity. Threats to the physical and living environment explained 22.2% of the variance in the rating of environmental and socioeconomic problems facing Nairobi. We were led to conclude that the respondents did not perceive climate change as being a significant problem in Nairobi. The global concern about climate change appeared like a mere drop in the oceanic context pervaded by problems of poverty, unemployment, crime and corruption, etc. which Nairobi faces, as does Kenya as a whole. Our conclusion is partially reflected in the priorities of the Kenyan government, which focus on poverty alleviation, the fight against crime and graft, improved access to education, and on addressing health problems; it also poses a challenge to the climate change community to find ways to making interventions relevant to local socioeconomic reality facing a developing country city like Nairobi. There may be a need to reconsider 'whose reality counts' (borrowing from Robert Chambers, Whose reality counts? Putting the first last, Intermediate Technology Publications, London, p 122, 1997) in addressing climate change: should protracted Kyoto protocol negotiations be given priority or should a long lasting solution be sought to socioeconomic problems facing developing world cities such as Nairobi? We recommend that the ongoing efforts at integrating climate risk management, as components of climate-sensitive sustainable development, be studied in many settings, with a focus on the developing world which is the most vulnerable, in order to inform decision-making and development of intervention measures. [ABSTRACT FROM AUTHOR]

The article offers information about a study which evaluates the simple urban energy balance model for mesoscale simulation (SUMM) using such data that are free from many real world uncertainties, in respect to spatial variability in material, geometry and land use. It also analyzes the sensitivity of land surface parameters (LSP), which are used in the model. In details, the model was evaluated by using the data obtained from comprehensive outdoor scale-model (COSMO) experiments during a period, covering half of year with winter and spring-early summer, including various wind conditions. Detailed information regarding the study is discussed.

The article offers information about research and future challenges in urban mesoscale. It is stated that the increase in environmental problems that are linked to urbanization and the increase in computational power are proposed as the main mechanisms behind the positive feedbacks between experimental investigation and numerical modeling in mesoscale urban studies. In the study, the modeling is the focus, with a description of state-of-the-art techniques used to parameterize urban-induced dynamical and thermal effects in mesoscale models. Detailed information regarding the study is discussed.