Spatial Distribution Of Air Temperature Research Articles

Effect of external shading on the temperature distribution performance of glass greenhouse in Wuhan region

The spatial temperature distribution within greenhouses plays a crucial role in agricultural management, particularly in large glass greenhouses that provide optimal growing conditions for crops. The current study investigated the effects of solar radiation and external shading on the spatial distribution of air temperature inside a large glass greenhouse. Experiments were conducted during summer in Wuhan, China, with cherry tomatoes grown under removable black plastic external shading (50 % transmittance). The use of external shading reduced greenhouse temperatures by 6.80 % on sunny days with air conditioning and 4.62 % on cloudy/rainy days without air conditioning. It also decreased the correlation between solar radiation and indoor temperatures by 60.71 % on sunny days and 7.20 % on rainy days. The greenhouse exhibited uneven temperature distribution in all directions, with much greater vertical temperature gradients (0.67 °C/m on sunny days, 0.33 °C/m on rainy days) compared to east-west and north-south directions. While external shading reduced overall temperature unevenness, on rainy days the north-south temperature difference was only 0.28 %, but the middle position was 2.24 % warmer than boundaries. The findings provide insights into regulating external shading techniques for large greenhouses in humid subtropical climates to optimize temperature management and crop production efficiency.

A novel method for optimizing air temperature estimation and quantifying canopy layer heat island intensity in eastern and central China

Many predictors are considered in estimating the spatial distribution of air temperature. However, a key problem remains the optimal selection of predictors. In this study, genetic algorithm (GA) was used to select optimal regression variables among 17 predictors, and GA-selected predictors were applied to random forest (RF) regression models for mapping air temperature in eastern and central China. By comparison with observed air temperature, results indicate that estimation errors of RF regression models constructed with GA-selected predictors first decrease (up to 5 predictors) and then remain stable. It is found that optimal combination of regression variables has the lowest estimation error (RMSE = 1.21 °C) and the best fitting precision (R2 = 0.9662), including 5 predictors that are latitude, relative humidity, elevation, distance to prefecture city and distance to third-order stream. Next, we compared the quantification of canopy layer heat island intensity (CLHII) based on the analysis of observed and estimated air temperature. We infer that quantification of CLHII using ground monitoring network results in obvious deviation due to the sparse weather stations only providing limited information over wide areas. Finally, we evaluated the robustness in quantifying the CLHII based on estimated air temperature derived from GA-1, -2, -3, -4, -5 and -17 models. Results show that the estimation of air temperature with low estimation error facilitates quantifying accurate CLHII, emphasizing the importance of selecting optimal regression variables. In summary, results reveal the effectiveness of GA in selecting optimal regression variables and provide insight into quantifying CLHII.

Projected changes in air temperature, precipitation and aridity in Serbia in the 21st century

AbstractIn this study, the projected changes of the average monthly and annual air temperatures, precipitation amounts and De Martonne aridity index in Serbia in the 21st century are examined. For that purpose, the spatial distribution of air temperature and precipitation amount is statistically modelled using data of 64 climatologic stations and 421 precipitation stations for the period 1976–2005 using multiple linear regression. The De Martonne aridity index is calculated from the spatially distributed data. In order to obtain regional averages and variability, we divide Serbia into three subdomains: the western zone (the Dinarides), eastern mountainous (Carpathian‐Balkan) zone and the terrains with altitudes lower than 500 m a.s.l. (Lowland). As a second step, the members of the COordinated Regional Downscaling EXperiment (CORDEX) for Europe (EURO‐CORDEX) are evaluated in terms of near‐surface air temperature and precipitation for Serbia. By comparing respective values for the period 1976–2005 with future periods 2021–2050 and 2071–2100, we derive the climate change signal for near‐surface air temperature, precipitation and the De Martonne index for both scenarios RCP4.5 and RCP8.5. Hereby, the ensemble averages are calculated as weighted averages using the inverse standardized Euclidean distance by comparing observation and model results for near‐surface air temperature and precipitation as a weight. We find for the period 2071–2050 that most ensemble members predict a statistically significant increase in monthly and annual near‐surface air temperature in both scenarios in all three subdomains, and a statistically significant decrease in the yearly De Martonne index in the RCP8.5 scenario in the Carpathian‐Balkan and Dinarides. For the last decades of the 21st century, our findings indicate much higher temperatures and increased risks of drought for the RCP 8.5 scenario compared to both the observations from 1976 to 2005 and the RCP 4.5 scenario.

A spatially explicit approach to simulate urban heat mitigation with InVEST (v3.8.0)

Abstract. Mitigating urban heat islands has become an important objective for many cities experiencing heat waves. Despite notable progress, the spatial relationship between land use and/or land cover patterns and the distribution of air temperature remains poorly understood. This article presents a reusable computational workflow to simulate the spatial distribution of air temperature in urban areas from their land use and/or land cover data. The approach employs the InVEST urban cooling model, which estimates the cooling capacity of the urban fabric based on three biophysical mechanisms: tree shade, evapotranspiration and albedo. An automated procedure is proposed to calibrate the parameters of the model to best fit air temperature observations from monitoring stations. In a case study in Lausanne, Switzerland, spatial estimates of air temperature obtained with the calibrated model show that the urban cooling model outperforms spatial regressions based on satellite data. This represents two major advances in urban heat island modeling. First, unlike in black-box approaches, the calibrated parameters of the urban cooling model can be interpreted in terms of the physical mechanisms that they represent; therefore, they can help promote an understanding of how urban heat islands emerge in a particular context. Second, the urban cooling model requires only land use and/or land cover and reference temperature data and can, therefore, be used to evaluate synthetic scenarios such as master plans, urbanization prospects and climate scenarios. The proposed approach provides valuable insights into the emergence of urban heat islands which can serve to inform urban planning and assist the design of heat mitigation policies.

Trends in the spatial distribution of agrometeorological indicators on the territory of the Chelyabinsk region in the second half of the XX - early XXI century

The article examines the trends in the spatial distribution of air temperature and precipitation indicators on the territory of the Chelyabinsk region for the period from 1936 to 2019. The average annual temperatures and precipitation were analyzed for 24 meteorological stations of the Chelyabinsk region. The results obtained made it possible to differentiate the study area according to the conditions of the thermal regime and the regime of humidification. The amplitudes of temperature growth were determined with a tendency to an increase in the number of differentiated zones, while a shift of the warming boundary to the north was noted. In mountainous areas, low temperature zones are shrinking and shifting to the northwest. The precipitation regime is orographic in nature, but there is a tendency towards a decrease in the continuity of the identified zones, as well as greater moisture content in the territory of steppe (arid) landscapes, which play an important role in agricultural production in the Chelyabinsk region.

Research on the relationship between urban morphology and air temperature based on mobile measurement: A case study in Wuhan, China

Urban morphology has an important impact on the outdoor thermal environment; studying the temporal and spatial distribution characteristics of air temperature and its relationship with urban morphology is the prerequisite for improving the outdoor thermal environment in the urban sectors. In July 2016, the study selected five sectors (C1 is a commercial sector, I1 is an industry sector, and R1-R3 are three residential sectors respectively) in the urban area of Wuhan to carry out the mobile measurement, and used ArcGIS tools to visualize the temporal and spatial distribution of air temperature, and then analyzed the correlation between air temperature and four indicators of urban morphology of the five sectors: building density(BD), vegetation coverage(VC), floor area ratio(FAR) and sky view fraction(SVF). The results suggested that: (1) In general, building density and floor area ratio are positively correlated with air temperature, while vegetation coverage and sky view fraction are negatively correlated with air temperature. (2) In the morning and evening hours, the maximum values of the average air temperature appear in the C1 (31.8 °C in the morning) and R1 (36.8 °C in the evening), which have the largest building density (56.4%) and the highest floor area ratio (4.87), respectively. While the lowest average temperature (27 °C in the morning, 31.5 °C in the evening) occurs in the R3 (a water-front residential sector) with a large lake surface and the lowest building density. In the afternoon, the highest air temperature (41.5 °C) and the maximum temperature difference (4.2 °C) both appear in the R3 sector which has a complex urban morphology, with large area lakes, high-density built-up areas and elevated road. (3) The water body has a significant cooling effect on the air temperature. In the R3 sector, the air temperature near the side of the water body is about 4.8 °C higher than the air temperature far from the side of the water body. (4) The relationship between floor area ratio, building density, sky view fraction and air temperature may not be a simple linear correlation, but there is a certain threshold. When they are greater than this threshold, the relationship between those indicators and air temperature will show an opposite trend. Since this phenomenon only occurs in some sectors, more data is needed to verify it.

Spatial distribution of air temperature and air flow analysis in radiant cooling system using CFD technique

This paper describes the air flow analysis and distribution of a radiant cooling system installed in a commercial building. Computational Fluid Dynamics (CFD) simulations using ANSYS were carried out to identify the thermal performance of the radiant cooling system. The calibration of simulated model was done using the actual data and a hypothetical case of conventional cooling system has been evaluated with the help of TRNSYS for comparative analysis. The CFD simulations were carried out to find the effect of the spatial distribution of air for the radiant system and the conventional system. It was recorded that a radiant cooling system maintains uniform air distribution and better average air temperature as compared to a conventional cooling system. Impact of thermal mass on the fluctuations of the temperature was also studied and it was identified that the higher thermal mass prevents high fluctuations in operative temperatures.

Use of Orbital Images and Interpolation Techniques: Climate Monitoring in Permanent Preservation Area (Humid Subtropical Climate)

The present work sought to demonstrate the importance using geoprocessing techniques and methodologies in the identification and analysis of the temporal and spatial distribution of air temperature. Therefore, an environment with difficulties for systematic monitoring of climatic elements was selected in the Serra da Esperançaárea, southern region of the State of Paraná. Two methodologies established in geoprocessing were used: the first deals with the interpretation of orbital images and the second makes reference to the interpolation of surface data. These methodologies, used in an integrated way, made it possible to know the relationship between the spatial and temporal distribution of air temperature with vegetation and the terrain altimetry. The air temperature data were monitored at 4 (four) points, following the contours of the federal highway that passes through the study area. Satellite images were obtained of July 26th, 2015 and January 18th, 2016, representing winter and summer southern conditions. The results indicated that this relationship exists and that in the absence of absolute data monitored at conventional collection points, geostatistics techniques allow good estimation. Moreover, this methodology can be used to control land use change in permanent preservation areas.

Spatial distribution of air temperature and relative humidity in the greenhouse as affected by external shading in arid climates

The effect of external roof shading on the spatial distribution of air temperature and relative humidity in a greenhouse (Tin and RHin) was evaluated under the arid climatic conditions of Riyadh City, Saudi Arabia. Two identical, evaporatively-cooled, single-span greenhouses were used in the experiment. One greenhouse was externally shaded (Gs) using a movable black plastic net (30% transmissivity), and the other greenhouse was kept without shading (Gc). Strawberry plants were cultivated in both greenhouses. The results showed that the spatial distribution of the Tin and RHin was significantly affected by the outside solar radiation and evaporative cooling operation. The regression analysis showed that when the outside solar radiation intensity increased from 200 to 800 W m–2, the Tin increased by 4.5°C in the Gc and 2°C in the Gs, while the RHin decreased by 15% in the Gc and 5% in the Gs, respectively. Compared with those in the Gc, more uniformity in the spatial distribution of the Tin and RHin was observed in the Gs. The difference between the maximum and minimum Tin of 6.4°C and the RHin of 10% was lower in the Gs than those in the Gc during the early morning. Around 2°C difference in the Tin was shown between the area closed to the exhausted fans and the area closed to the cooling pad with the external shading. In an evaporatively-cooled greenhouse in arid regions, the variation of the Tin and RHin in the vertical direction and along the sidewalls was much higher than that in the horizontal direction. The average variation of the Tin and RHin in the vertical direction was 5.2°C and 10% in the Gc and 5.5°C and 13% in the Gs, respectively. The external shading improved the spatial distribution of the Tin and RHin and improved the cooling efficiency of the evaporative cooling system by 12%, since the transmitted solar radiation and accumulated thermal energy in the greenhouse were significantly reduced.

Optymalizacja procesu projektowego stałych urządzeń gaśniczych gazowych za pomocą metod numerycznych CFD

Computational fluid dynamics (CFD) is a modern tool used in engineering practice that can be used to optimize the design of fixed gaseous extinguishing systems (FGE-systems). The paper presents selected possibilities of practical application of numerical methods for evaluation of individual FGE-systems design parameters. The main feature of CFD modeling is the ability to obtain gas concentration distributions, flow directions of fire extinguishing mixture in a protected room and spatial distribution of air temperature, which is an important cognitive value of this method. The results show the potential for practical use of CFD methods in the modeling of extinguishing gas protection of real properties.

Spatial Distribution of Air Temperature during an Extreme Heat Period in Daegu Metropolitan Area in 2016

Spatial Distribution of Air Temperature during an Extreme Heat Period in Daegu Metropolitan Area in 2016

Study of mobile measurements for detailed temperature distribution in a high-density urban area in Tokyo

Due to the low spatial resolution of measurements from meteorological observation stations, it is difficult to observe urban environmental parameters at a scale relevant to people's daily lives. Mobile measurements can be an effective method of investigating the distribution of environmental conditions in urban areas. However, the effectiveness of mobile measurements is unclear as it is difficult to obtain accurate positioning data for each sample due to Global Positioning System (GPS) errors that may be >20m in urban areas. We conducted a mobile measurement study during August 25th to 28th, 2015, in Shinjuku, Tokyo, one of the most crowded areas in Japan, to investigate the spatial distribution of air temperature and the range of GPS errors. We equipped bicycles with thermometers and high temporal resolution GPS loggers to measure air temperature and spatial position. The results demonstrated that the range of air temperature variation was almost 2°C on cloudy days, and that the spatial distribution of air temperature differed for different measurement routes. A spatial resolution in the order of 101m was required to detect locations where the air temperature was locally high, such as near street intersections.

贵州省平均气温和光照时空变化特征分析

采用1951年至2010年贵州省19个台站平均气温和日照时数逐日数据，统计了其年平均值，运用Mann-Kendall突变检验法、小波分析法、滑动平均法和线性趋势比较法等，并统计其气候倾向率，来分析贵州省平均气温和日照时数随时间和空间的变化特征。结果表明：贵州省年平均气温呈上升趋势，气温的分布在全省呈东南向西北降温态势；全省的日照时数呈现先上升后持续减少，近10年来又回升的趋势，在全省的分布为自西南向东北减少的态势。 Based on the time series of daily average air temperature and sunshine duration of Guizhou Province from 1951 to 2010, the average air temperature and annual sunshine duration was calculated by using the methods of Mann-Kendall abrupt change test, wavelet analysis and moving average method to analyze the climatic trend rate and saptial-temporal characteristics of temperature and sunshine duration of Guizhou Province. The result showed that, the average air temperature of Guizhou has witnessed a continuing rise and the air temperature of the south-east part is higher than the north-west part. The sunshine duration of Guizhou climbed in the 1960s and started to decline since 1970s. However, the sunshine duration showed an increasing trend in the past 10 years. Different with the spatial distribution of air temperature, the sunshine duration of southwest area is more than the north-west area.

CONTRIBUTION OF MODIS SATELLITE IMAGE TO ESTIMATE THE DAILY AIR TEMPERATURE IN THE CASABLANCA CITY, MOROCCO

Abstract. Air temperature is considered to be an essential variable for the study and analysis of meteorological regimes and chronics. However, the implementation of a daily monitoring of this variable is very difficult to achieve. It requires sufficient of measurements stations density, meteorological parks and favourable logistics. The present work aims to establish relationship between day and night land surface temperatures from MODIS data and the daily measurements of air temperature acquired between [2011-20112] and provided by the Department of National Meteorology [DMN] of Casablanca, Morocco. The results of the statistical analysis show significant interdependence during night observations with correlation coefficient of R2=0.921 and Root Mean Square Error RMSE=1.503 for Tmin while the physical magnitude estimated from daytime MODIS observation shows a relatively coarse error with R2=0.775 and RMSE=2.037 for Tmax. A method based on Gaussian process regression was applied to compute the spatial distribution of air temperature from MODIS throughout the city of Casablanca.

Temporal and spatial patterns of air temperature in a coastal city with a slope base setting

AbstractIn coastal cities with a slope base setting, effects of sea breeze and cold air drainage superpose on top of the urban heat island (UHI) effect. It is difficult to articulate the urbanization effect which, however, is important in developing summer heat mitigation solutions. The aim of this study is to address this challenge by investigating the temporal and spatial distribution of air temperature in the Adelaide metropolitan area of South Australia based on data from a monitoring network in 2011–2013. The results indicate that the dominant influence on the spatial variability of air temperature in winter is the urban heat island effect, followed by the prevailing nighttime northeasterly wind and cold air drainage. In summer, the dominant influence comes from daytime sea breezes, followed by the urban heat island effect, and the prevailing southeasterly nighttime wind. The urban heat island intensity is estimated based on various references where the influence of other factors is minimal. A clear nighttime urban heat island is observed over the Adelaide metropolitan area, with a mean intensity of 2.5°C for both summer and winter. The daytime urban heat island is not clear. On hot days, the city center develops a dominant nighttime urban heat island about 4°C warmer than the coast, stronger than an average summer night. Given multiple influences on the thermal climate in the Adelaide metropolitan area, it is suggested that the unique 500 m wide Adelaide parkland belt surrounding the city center be used as a reference to evaluate the Adelaide city center urban heat island in summer. A rural station, Edinburgh, can be used to evaluate the nighttime urban heat island intensity in the study area.

VARIABILIDADE ESPACIAL DA TEMPERATURA DO AR COM USO DE TRANSECTOS MÓVEIS EM ERECHIM/RS, SOB DOMÍNIO POLAR EM PROCESSO DE TROPICALIZAÇÃO

This research concerns in to analyze the spatial distribution of air temperature in the urban area of ​​Erechim/RS, under polar domain tropicalization process. In carrying out this climate research in loco needed to conduct field work with implementing the mobile transects methodology. Was measured air temperature 15 PM. It was made spatial variation map of air temperature recorded in the urban environment and used the synoptic maps, satellite imagery and data of the official network of weather INMET stations for identification of active weather systems and comparisons with the data and its magnitude. After climate and cartographic analysis, it was observed that the thermal variations on this primary research, occurred significantly, registering differences of up to 46,4°F between the districts of the city, and amortization that green areas can play in this environment, reducing up to 50% of the highest temperatures recorded in Erechim. Still, for this city, slope aspect and the presence of water bodies, were very important to the spatial differentiation of temperature compared to the industrial areas, low-income peripheral and central/commercial.

Application of Open Source Electronics for Studying High Frequency Urban Heat Island

A new measurement system based on open source electronics (Arduino) was designed to obtain high frequency data to study Urban Heat Island (UHI). The instrument registers geo-referenced information of air temperature, relative humidity, barometric pressure and altitude above sea level in a moving vehicle. The device was designed to analyze the UHI in Bahia Blanca city, Argentina. Measurements were made with the method of urban transects during different days of summer and winter. The spatial distribution of air temperature was associated with wind direction and speed. Relative humidity was low in the downtown area and high in the periphery and the estuarine coast. In conclusion, the device allowed to study the Urban Heat Island in the city. Its use will be useful for urban planning because the measurements are very fast and accurate.

Spatial distribution of air temperature in Toruń (Central Poland) and its causes

In this article, the results of an investigation into the air temperature pattern and development (including the urban heat island (UHI)) in Torun (central Poland) are presented. For the analysis, daily mean temperature (Ti) as well as daily maximum (Tmax) and minimum (Tmin) temperatures for 2012 gathered for 20 sites, evenly distributed in the area of city, have been taken as source data. Additionally, in order to provide more extensive characteristics of the diversity of the air temperature in the study area, the diurnal temperature range (DTR) and the number of the so-called characteristic days were calculated as well. The impact of weather conditions (cloudiness and wind speed), atmospheric circulation, urban morphological parameters and land cover on the UHI in the study area was investigated. In Torun, according to the present study, the average UHI intensity in 2012 was equal to 1.0 °C. The rise of cloudiness and wind speed led to a decrease of the magnitude of the UHI. Generally, in most cases, anticyclonic situations favour increased thermal contrast between rural and city areas, particularly in summer. Warm western circulation types significantly reduced temperature differences in the western side of the city and enlarged them in the eastern side of the city. Eastern cold types also have a similar influence on air temperature differences. Positive and statistically significant correlations have been found between the percentage of built-up areas (sealing factor) and air temperature. Conversely, sky view factor (SVF) reveals negative correlations which are statistically significant only for Tmin.

Influence of vegetation and building geometry on the spatial variations of air temperature and cooling rates in a high‐latitude city

ABSTRACTThe aim of this study was to provide a better understanding of how vegetation and building geometry influence the spatial distribution of air temperature and nocturnal cooling rates (CR) in a high‐latitude city. Intra‐urban thermal variations were analysed in two seasons (May–September and November–March) and in different weather conditions (clear, calm and cloudy, windy) in Gothenburg, Sweden. Simultaneous air temperature measurements were conducted for 2 years (2012–2013) at ten fixed park and street sites characterized by varying type and amount of vegetation, building geometry, openness and surface cover. Several spatial characteristics, including sky view factor (SVF) as well as the cover and volume of buildings and trees, were calculated within circular areas of radii ranging from 10 to 150 m. Spatial characteristics were found to explain air temperature distribution in the studied area to a large extent throughout the day and year, in both clear, calm as well as cloudy, windy conditions. The highest correlations were found for weighted calculation areas accounting for the influence of both nearest (10 m) and wider (25–150 m) surroundings. Park sites remained cooler than built‐up areas, with the most pronounced cooling effect (0.8 °C) on clear, calm days of the warm season. The most important factor governing CR around sunset was SVF. However, on clear, calm nights of the warm season, they were also enhanced by vegetation, indicating the influence of evapotranspiration. Minimum night‐time air temperature was governed mostly by the presence of buildings. Within the street canyon, a daytime cooling and night‐time warming effect of a street tree was observed, particularly in the warm season. The study shows the importance of various spatial characteristics describing openness, amount of vegetation and building geometry in analysing intra‐urban variations in daytime and night‐time air temperature.

Spatial distribution of air temperature on Svalbard during 1 year with campaign measurements

ABSTRACTIn this article, the results of an investigation into the air temperature conditions on Svalbard in the period 1 September 2010 to 31 August 2011 are presented. For this period, parallel temperature measurements have been made as many as in 30 sites. On the basis of this unique set of data it was possible to study, in detail, the spatial distribution of different thermal characteristics [mean temperature, diurnal temperature range (DTR), day‐to‐day variability, degree of climate continentality, etc.] in Svalbard. Such knowledge of the whole of Svalbard was not previously available with sufficient accuracy for all areas. High resolution maps showing the spatial distribution of all studied thermal characteristics were also produced and analysed.Analysis of surface temperature data shows that the markedly coldest area throughout the whole year was northern Svalbard, and in particular its eastern side (Nordaustlandet). On the other hand, the highest temperatures were recorded in western part of Spitsbergen. The greatest spatial decreasing rate of temperature in Svalbard throughout the whole year was observed in a southwest (SW)–northeast (NE) direction. The distribution of mean seasonal and annual temperature reduced to sea level on Svalbard differs from the distribution based on surface temperatures. Spring, and in particular winter, saw the greatest DTRs (4–7 and 6–9 °C, respectively), while the lowest were observed in summer (3.0–3.5 °C). In all seasons, the highest DTR were mainly noted in the NE part of Svalbard, while the lowest were in its SW part. The lowest continentality of climate (30%) is clearly seen in the south‐western part of Svalbard, while the highest values (above 43%) stretch from the western part of Nordaustlandet to the area of Sveagruva in the central‐eastern part of Spitsbergen. The NORA10 hindcast temperature data differ significantly from measured data for some seasons and areas and need bias corrections when used in climatology.