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This experimental study investigates the influence of indoor plants on three aspects of air quality in office spaces: relative humidity, indoor air temperature, and carbon dioxide concentration. Employing a Latin square design, we rotated three different treatments across three offices over six time periods. These treatments included a control (no plants), a low-volume treatment (five plants), and a high-volume treatment (eighteen plants) of Nephrolepis exaltata (Boston fern). Air quality parameters were continuously monitored at five-minute intervals using Trace Gas Analyzers. Generalised linear mixed modelling (GLMM) was employed to examine the effect of each treatment on relative humidity, indoor air temperature and CO2 concentration. We observed a significant positive correlation between the number of indoor plants and relative humidity levels. In offices without any plants, the median relative humidity was 29.1%. This increased to 38.9% in offices with 5 plants and further to 49.2% in offices with 18 plants. However, we did not find significant associations between the number of indoor plants and indoor air temperature or corrected CO2 concentration. Our research provides support for the use of indoor plants to increase relative humidity, which can have health benefits in dry climates, but does not provide support for using indoor plants to regulate indoor air temperatures or CO2 concentration in office environments. [ABSTRACT FROM AUTHOR]

The rapid industrialization of nations in Southeast Asia (SEA) has led to a decline in these countries' air quality, including high levels of particulate matter (PM). Monitoring these air pollutants is crucial to understanding the pollution status of the area and developing management plans for improvement. The metrological conditions in the region present challenges as high temperature and high humidity have been known to cause errors in the measurements. This study investigated the performance of five PM monitoring instruments with different working principles. The air temperature was mostly over 25 °C with relative humidity usually remaining above 80%, which is typical of SEA weather. Measurements from all instruments had good correlations with each other as their linear regressions yielded slopes of 1 ± 0.15 and R2 > 0.65. Moreover, this study found that depending on the chosen reference instrument, not all factors affect the devices equally. In particular, using Partisol as a reference, the PM2.5 concentration, air temperature, and relative humidity had less impact upon the relative bias level compared to using Leckel as a reference. In addition, the high cost of monitoring instruments also poses financial constraints on how many monitoring stations can be deployed. To tackle this issue, this study presents ManPMS whose design is based on that of the USEPA Title 40 Part 50 with slight modifications. The cost to manufacture and assemble the instrument was only 2/3 the price of a typical instrument with similar performance. [ABSTRACT FROM AUTHOR]

A class first Pyranometer is used to measure the direct solar irradiation and the results were analyzed. Separate sensors used to measure the relative humidity and the atmospheric temperature (RH/AT sensors). The measurements made for the whole year of 2013. We analyzed the collected solar data during one day, month, and year. The maximum, minimum, average, and accumulative solar irradiation (SR) are calculated and analyzed with the connection to relative humidity and atmospheric temperature. We found that April gave the average maximum solar irradiation (SR= 1112±1W/m2), May gave the maximum SR accumulation (13276552± 1W/m2). The maximum average percentage relative humidity found in July (% RH = 97± 3%), while the minimum average % RH is in December (% RH = 25± 3%). In the month of May, the maximum average atmospheric temperature is 36.0 ± 0.6oC, while the average minimum is in January (AT= 19.1 ± 0.6oC). The total accumulation of solar flux during the year 2013 is 222 ± 1MW/m2.

The main objective of this study is to optimize relative humidity based on the heat transfer terms of thermoelectric atmospheric water generator from moisture in the air. The experimental thermoelectric atmospheric water generator is maintained with a 0.04 × 0.04 m2 thermoelectric cooler that can condense water vapor. The analysis shows that electricity, air mass rate, relative humidity, and incoming air temperature affect the quality and quantity of water produced from the atmosphere. The results show that increasing atmospheric moisture at a constant temperature rises the amount of water produced from the atmosphere. It is concluded that a thermoelectric AWG designed with thermos electric cooling as an electric condenser has excellent potential as a kind of power generation through renewable energy sources from the atmosphere. On the other hand, the conducted tests show that by reducing the temperature of the cooling water, the amount of produced water and the efficiency of the device increase. While the temperature of inlet air is 37 °C, the humidity is 95 %, and the electric current intensity of thermoelectric is 1 A , the amount of generated water reached 96 ml h−1. The amount of water generated for the experimental device equals 82 ml h−1. [ABSTRACT FROM AUTHOR]

This article is to study the criteria of dehydration model, and to establish the Brixter index. Coffee cherries (Coffea arabica L. var. catimor) were selected from two different farms in Pangkhon village, Chiang Rai province, which are in the northern part of Thailand: Farm A, and Farm B. The low air temperatures (18–30 °C) and low relative humidities (65–30%) technique (LTLH) was gradiently applied, to dehydrate the coffee bean, leading to higher sugar concentration. The applicability of the various measurements, such as physicochemical properties, dehydration kinetic, Brix boosting parameters, and their correlations were investigated. The level of soluble solids (°Brix) and acid concentrations in coffee samples were analyzed, to determine the °Brix/acid and oBrix*pH2 ratios. The qualities of coffee cherries changes depending on the decreasing level of moisture content during the dehydration process. The °Brix degree reveals that by the end of the dehydration process, the sugar concentration of coffee cherries has increased by 1.5 times that of its initial. The °Brix/acid, and oBrix*pH2 ratios highly correlated to the amount of soluble solids (r2 = 0.923 and 0.972, respectively) within coffee cherries. The most suitable timing to select dehydrating coffee cherries for the fermentation process is when the coffee cherries have attained °Brix/acid ratio of > 10 to 33, and oBrix*pH2 ratio of > 400 to 850. These ratios can be used as an efficient instrument to determine the optimum Brix boosting stage of coffee cherry in the LTLH system. [ABSTRACT FROM AUTHOR]

This study analyzes the long‐term observed changes of mean (Tmean), maximum (Tmax) and minimum (Tmin) air temperatures, relative humidity (RH) and vapour pressure deficit (VPD) at different elevation ranges across Bolivia from 1950 to 2019. The linear trends in air temperature series present a significant increase, with no substantial seasonal or spatial differences. On an annual basis, RH exhibited a non‐significant decrease (−0.08% decade−1), while VPD showed a significant increase (0.01 hPa decade−1) (p < 0.05). Although prior research has suggested that highland elevations experience faster warming than the global average, we have not identified a distinct correlation between elevation gradients and differential warming rates in Bolivia. Future research could investigate elevation‐dependent climate trends by examining seasonal and monthly patterns of climatic variables in relation to topographical gradients in various highland regions. [ABSTRACT FROM AUTHOR]

In this study, a new technique is proposed to retrieve temperature and relative humidity profiles under clear sky conditions in the Arctic region based on the artificial neural network (ANN) algorithm using Fengyun-3D (FY-3D) vertical atmospheric sounder suit (VASS: HIRAS, MWTS-II, and MWHS-II) observations. This technology combines infrared (IR) and microwave (MW) observations to improve retrieval accuracy in the middle and low troposphere by reducing the sensitivity of the neural networks (NNs) to cloud coverage. The approach was compared against other methods available in the literature on retrieving profiles only from FY-3D/HIRAS data. Furthermore, its retrieval performance was tested by comparing the NNs' prediction accuracy versus the corresponding FY-3D/VASS and Aqua/AIRS L2 products. The results showed that: (1) NNs retrieval accuracy is higher during the warm season and over the ocean; (2) the retrieval accuracy of NNs has been significantly improved compared with satellite L2 products; (3) referring to radiosonde observations, the retrieval accuracy of NNs below 600 hPa is effectively improved by adding the information of the MW channel, especially on land where cloud clearing is more difficult. The root mean square error (RMSE) of temperature and relative humidity in the cold season were reduced by 0.3 K and 2%, respectively. The advanced NNs proposed herein offer a more stable retrieval performance compared with NNs built only by FY-3D/HIRAS data. The study results indicated the potential value in time and space domain of the NN algorithm in retrieving temperature and relative humidity profiles of the Arctic region from FY-3D/VASS observations under clear-sky conditions. All in all, this work enhances our knowledge towards improving operational use of FY-3D satellite data in the Arctic region. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the possibility of using meteorological data obtained from a public meteorology station in determining the effect of air temperature and relative humidity on milk yield in Holstein dairy cattle raised in Diyarbakir province of Türkiye. Records on daily milk yield obtained from a commercial farm were used in the study. Meteorological records including daily maximum and minimum temperatures and daily maximum and minimum humidity data were obtained from the nearest public weather station. A total of 185 healthy Holstein dairy cattle, with five different lactation parities, as well as details on some environmental conditions such as, year, month, lactation period, weather temperature, and the humidity that the animals are exposed to are included in the dataset relating to milk production. Five different temperaturehumidity index variants, including THIa (maximum temperature and humidity), THIb (minimum temperature and humidity), THIc (average temperature and humidity), THId (maximum temperature and minimum humidity), and THIe (minimum temperature and maximum humidity), were considered to evaluate the effect of heat stress on milk production. The critical values at which the milk yield began to decrease due to heat stress in this study slightly deviated from the critical value of 72, which is accepted as the threshold value for the start of heat stress and determined as 77, 54, 64, 69, and 54 for THIa, THIb, THIc, THId, and THIe, respectively. Based on these values, the loss of milk production of one cow per year was calculated as 98.25, 157.68, 207.36, 164.30, and 190.08 kg when using THIa, THIb, THIc, THId, and THIe, respectively. This study confirmed that weather stations located away from farms provide useful information for research on heat stress in dairy cows. It can be concluded that THId, which shows the least deviation from the critical value of 72 (only 3 unit), better reflects the stress condition that animals are exposed to due to temperature and humidity. For this reason, the highest daily air temperature and lowest daily humidity appear to be the most important factors in this investigation to assess heat stress and both variables can be combined into a THI. [ABSTRACT FROM AUTHOR]

The skill of the atmospheric reanalysis ERA5 from the European Centre for Medium-Range Weather Forecasts (ECMWF) at simulating upper atmospheric temperature and relative humidity is assessed by using five years of In-service Aircraft for a Global Observing System (IAGOS) observations. IAGOS flight trajectories are used to extract co-located meteorological conditions – temperature, relative humidity, and wind speed – and are compared with the IAGOS measurements. This assess ment is particularly relevant to the study of contrail formation, so focuses on the highly frequented air space that spans the Eastern United States over the North Atlantic and to central Europe. The comparison is performed in terms of mean, median, probability density functions, and a confusion matrix. For temperature a good agreement is identified with a maximum bias of − 0.4 K at the 200 hPa level. Larger biases are found for relative humidity with up to − 5.5 % at the 250 hPa level. To remove the systematic biases, which mostly tend towards too dry and cold, a bias correction method, based on a multivariate quan tile technique, is proposed and applied. After the correction the bias in temperature is reduced to below 0.1 K and in relative humidity to below − 1.5 %. To estimate the representation of contrail occurrence in ERA5, data points from IAGOS as well as corrected and uncorrected data points from ERA5 of temperature and relative humidity are flagged for contrail formation using the Schmidt-Appleman–criterion. In the IAGOS data set 39.2 and 16.9 % of the samples represent conditions for non-persistent contrails and persistent contrails, respectively. The corresponding numbers for original ERA5 analyses are 40.8 and 17.5 %, respectively, indicating good agreement overall. Applying a proposed quantile mapping correction method and removing the biases in temperature and relative humidity has only a small effect on the distributions but leads to an overestima tion of non-persistent contrail occurrence (44.0 %) and underestimation of persistent contrails (16.8 %). Differences in contrail occurrence that remain after the bias correction are traced back to the underling biases in temperature and relative humidity, indicating that ERA5 is either too dry and warm or cold and moist with largest differences at 250 hPa and decreasing with increasing altitude. [ABSTRACT FROM AUTHOR]

It has generally been regarded that, in the warming climate, atmospheric water vapor may increase due to the enhancement in surface evaporation, which is expected from the Clausius–Clapeyron (C–C) equation, along with the assumption that relative humidity experiences small changes. If the variation in relative humidity is small, the response of water vapor to temperature will be closely in line with the C–C equation. However, whether relative humidity experiences large or small changes needs be assessed, and the change of relative humidity should be compared with the change in surface–air temperature. In this study, we link surface vapor pressure, which characterizes atmospheric water vapor, to surface-air temperature, and treat both the temperature and relative humidity as influencing factors. A method based on linear regression is applied to compare the interannual variabilities of relative humidity and temperature in the interannual variation in surface vapor pressure. Whether the year-to-year perturbation of relative humidity is important, compared with the perturbation in surface-air temperature, is explored Results show that, at high latitudes of both hemispheres, the variation in vapor pressure is dominated by air temperature, and relative humidity has small positive contributions. Thus, the variation in relative humidity over these regions is comparably small, and the response of water vapor to temperature can well follow the C–C equation. Differently, at mid-low latitudes, especially on land, air temperature plays a negative role in the variation in vapor pressure. Relative humidity offsets the negative contribution and dominates the variation in vapor pressure, suggesting that the variation in the relative humidity over these regions is comparably large. Hence, the response of water vapor to temperature deviate from the C–C equation. Analysis indicates that the different results of the dominance from the two influencing factors are affected by the dual effects of precipitation or wet-air transport over land. Both precipitation and the transport of cold wet air could break the C–C relation between water vapor pressure and temperature. [ABSTRACT FROM AUTHOR]

In order to explore the indoor air quality during different cooking procedures, a very common kitchen in China is selected for experimental research. An indoor air quality meter is used to measure the temperature, relative humidity, and CO and CO2 concentrations of the indoor air above the stove when people cook four different dishes under different ventilation patterns in the kitchen. The results indicate that the heat and gas consumed during cooking are closely related to the temperature and concentrations of CO and CO2. Some cooking procedures such as boiling water are related to the indoor air temperature and relative humidity in the kitchen. In addition, in kitchens without mechanical ventilation, natural ventilation shows a more significant positive effect on controlling temperature, relative humidity, and concentrations of CO and CO2 during cooking procedures. [ABSTRACT FROM AUTHOR]

Climate change causes extreme heat and high humidity in some regions. The wet-bulb temperature (Tw) is a heat stress index, and the threshold is 35 °C. It is difficult to measure the value of Tw using a psychrometer, but the Tw value can be calculated using the air temperature and humidity. To provide accuracy for the Tw calculation, an empirical equation is established using regression analysis. This study defines the empirical equation as Tw = − 4.391976 + 0.0198197 RH + 0.526359 Td + 0.00730271 RH · Td + 2.4315 × 10 − 4 RH 2 − 2.58101 × 10 − 5 Td · RH 2 , where Td is the air temperature in °C and RH is the relative humidity in %. This equation applies to a temperature of 20~45 °C and RH of 40~99%. The fit is better than that for the Stull equation in this range. The prediction accuracy is 0.022 °C and there is no fixed pattern for the error distribution for the range of Td and RH. The measurement uncertainty for Tw values for thermometer and humidity sensors that are not calibrated is 1.4~2.2%. If these sensors are calibrated, the measurement uncertainty for Tw values is 0.16~0.28 °C. Therefore, well-calibrated sensors are necessary to enhance the accuracy of the Tw predictive equation. [ABSTRACT FROM AUTHOR]

In the years 2018-2021, experiments on the effect of air temperature and relative humidity (RH) on the storage of Welsh onion (Allium fistulosum L.) seeds were carried out. Three different cultivars and one breeding line received from commercial plant breeding and seed production companies were used. All their seeds at the beginning of storage had high germination over 90%, and moisture content 7-8%. Then, they were stored for 30 months in the controlled conditions at 3 different temparatures: 7-8 °C, 10 °C and 25 °C, each with 2 different air relative humidty (RH): 25% or 45%. During the experiment, their quality was evaluated by germination test according to the International Seed Testing Association (ISTA) protocol. Additionally, after 1 and 2 years of storage at 7-8 °C and 25% air RH, the seeds of the line were evaluated for their incidence of fungi. It was found out that seeds of the tested genotypes kept good germination at 7-8 °C and at 10 °C, i.e. after storing them, the same effect was achieved. Thus, the latter can effectively lower the costs of the seed storage in commercial seed trade of the crop. The electric current consumption for the seeds stored at 7-8 °C in comparison with 10 °C was higher by 11.2%. In seeds of 3 genotypes, after storing them for 30 months, their germination was better at the air RH 45% than at 25%. Generally, low temperature (7-8 °C) favoured growth of Penicillium spp. and Phoma spp. on Welsh onion seeds during 2 years of storage, while storing at higher temperature (25 °C) resulted in the increase in seed infestation with Cladosporium spp. and Fusarium spp. The results obtained from this research can be used as a guideline for the storage in climatic and RH controlled chambers of all genotypes belonging to Allium fistulosum species, with the aim to maintain its seed germination quality related to the duration of the storage and taking into consideration the operating energy costs. [ABSTRACT FROM AUTHOR]

Because hurricanes, droughts, floods, and heat waves are all important factors in measuring environmental changes, they can all result from changes in atmospheric air temperature and relative humidity (RH). Besides, climate, weather, industry, human health, and plant growth are all affected by RH. Accurately and consistently forecasting RH is a challenge due to its non-linear nature. The present study tried to predict one day ahead of RH in determined provinces from different climatic regions of Turkey (Ankara, Erzurum, Samsun, Diyarbakır, Antalya, and Bilecik) using long short-term memory (LSTM) and adaptive neuro-fuzzy inference system (ANFIS) with fuzzy c-means (FCM)–based machine learning models. As evaluation criteria, root mean square error (RMSE), mean absolute error (MAE), and correlation coefficient (R) were employed. The outcomes from the forecasting models were also validated using observed data. During the testing stage, the smallest MAE and RMSE values were discovered to be 5.76% and 7.51%, respectively, in Erzurum province, with an R value of 0.892 when using the LSTM method. Moreover, the smallest MAE and RMSE values were obtained to be 5.95% and 7.67%, respectively, in Erzurum province with an R value of 0.887 using the ANFIS model according to the daily RH prediction. The results indicate that both the LSTM and ANFIS approaches performed satisfactory performance in daily RH prediction, with the LSTM and ANFIS approaches producing nearly identical results. [ABSTRACT FROM AUTHOR]

The aim of the study is to characterise the changes in the proportion of impervious surfaces (ISs) in Poland and their impact on changes in temperature, air humidity, and cloud cover. The results of satellite image classification from 1990, 2000, 2010 and 2020, as well as meteorological data from the period 1981–2020 for the warm half of the year, were used. An analysis was performed making it possible to compare the changes in the proportion of ISs in 3 decades, i.e. 1991–2000, 2001–2010 and 2011–2020. In Poland, in the years 1991–2020, the total area of ISs increased by approximately 30%. At the same time, statistically significant positive trends in maximum temperature are visible throughout Poland, ranging from 0.48°C per 10 years to >0.90°C per 10 years. Trends in the magnitude of low-level cloud cover are negative throughout Poland and range from −2.7% to −2.3% per 10 years. The frequency of stratiform clouds is decreasing, while that of mid-level Cirrus and Cumulus clouds is increasing. The results show a relationship between the increase in ISs in Polish cities and changes in meteorological elements in their area and in the immediate vicinity, which were most pronounced in the first decade of the 21st century. [ABSTRACT FROM AUTHOR]

NIWA has recently digitised daily wet- and dry-bulb temperature records for both Kelburn, Wellington and Masterton, Wairarapa sites back to 1929 and undertaken an analysis of these records and comparison with reanalysis products. This article presents key results of the analysis in the context of climate change and also the steps taken to account for site moves, complications around a plethora of daylight savings changes, and observing methods. Overall, there was a 0.7°C increase in dewpoint temperature (Td) averaged over all seasons with the strongest trend being an increase in winter, amounting to +1.7°C over 90 years at Kelburn, and +1.8°C at Masterton for the same period. Autumn also saw increasing trends at both locations whereas summer and spring saw smaller increases. Other points of interest were that January 2018 had the highest average Td values of any month in both the Kelburn and Wairarapa records while February 1998 was ranked third in the Kelburn record. Both 1998 and 2018 are tied for third-warmest years on record for Aotearoa New Zealand (dry-bulb air temperature). Despite the long-term upward trend, average Td values for February 1938 and February 1935 were ranked second- and tenth-highest respectively in the Kelburn record. February 1935 is also ranked eighth-highest in the Wairarapa record. Extreme high summer and autumn values of Td occurred in the 1930s where there was considerable yearto-year variability. Of the ten months with lowest average Td values, seven occurred in the 1930s and 1940s for Wellington. At Masterton, six were in the 1930s and all ten had occurred by 1972. [ABSTRACT FROM AUTHOR]

The focus of this study was to identify the effects of increasing ambient temperature (T) at different relative humidity (RH) and air velocity (AV) levels on heat loss from the skin surface and through respiration of dairy cows. Twenty Holstein dairy cows with an average parity of 2.0 ± 0.7 and body weight of 687 ± 46 kg participated in the study. Two climate-controlled respiration chambers were used. The experimental indoor climate was programmed to follow a diurnal pattern with ambient T at night being 9°C lower than during the day. Night ambient T was gradually increased from 7 to 21°C and day ambient T was increased from 16 to 30°C within an 8-d period, both with an incremental change of 2°C per day. A diurnal pattern for RH was created as well, with low values during the day and high values during the night (low: RH_l = 30–50%; medium: RH_m = 45–70%; and high: RH_h = 60–90%). The effects of AV were studied during daytime at 3 levels (no fan: AV_l = 0.1 m/s; fan at medium speed: AV_m = 1.0 m/s; and fan at high speed: AV_h = 1.5 m/s). The AV_m and AV_h were combined only with RH_m. In total, there were 5 treatments with 4 replicates (cows) for each. Effects of short and long exposure time to warm condition were evaluated by collecting data 2 times a day, in the morning (short: 1-h exposure time) and afternoon (long: 8-h exposure time). The cows were allowed to adapt to the experimental conditions during 3 d before the main 8-d experimental period. The cows had free access to feed and water. Sensible heat loss (SHL) and latent heat loss (LHL) from the skin surface were measured using a ventilated skin box placed on the belly of the cow. These heat losses from respiration were measured with a face mask covering the cow's nose and mouth. The results showed that skin SHL decreased with increasing ambient T and the decreasing rate was not affected by RH or AV. The average skin SHL, however, was higher under medium and high AV levels, whereas it was similar under different RH levels. The skin LHL increased with increasing ambient T. There was no effect of RH on the increasing rate of LHL with ambient T. A larger increasing rate of skin LHL with ambient T was observed at high AV level compared with the other levels. Both RH and AV had no significant effects on respiration SHL or LHL. The cows lost more skin sensible heat and total respiration heat under long exposure than short exposure. When ambient T was below 20°C the total LHL (skin + respiration) represented approx. 50% of total heat loss, whereas above 28°C the LHL accounted for more than 70% of the total heat loss. Respiration heat loss increased by 34 and 24% under short and long exposures when ambient T rose from 16 to 32°C. [ABSTRACT FROM AUTHOR]

With a modified version of the Wells-Riley model, we simulated the size distribution and dynamics of five airborne viruses (measles, influenza, SARS-CoV-2, human rhinovirus, and adenovirus) emitted from a speaking person in a typical residential setting over a relative humidity (RH) range of 20–80% and air temperature of 20–25 °C. Besides the size transformation of virus-containing droplets due to evaporation, respiratory absorption, and then removal by gravitational settling, the modified model also considered the removal mechanism by ventilation. The trend and magnitude of RH impact depended on the respiratory virus. For rhinovirus and adenovirus humidifying the indoor air from 20/30 to 50% will be increasing the relative infection risk, however, this relative infection risk increase will be negligible for rhinovirus and weak for adenovirus. Humidification will have a potential benefit in decreasing the infection risk only for influenza when there is a large infection risk decrease for humidifying from 20 to 50%. Regardless of the dry solution composition, humidification will overall increase the infection risk via long-range airborne transmission of SARS-CoV-2. Compared to humidification at a constant ventilation rate, increasing the ventilation rate to moderate levels 0.5 → 2.0 h−1 will have a more beneficial infection risk decrease for all viruses except for influenza. Increasing the ventilation rate from low values of 0.5 h−1 to higher levels of 6 h−1 will have a dominating effect on reducing the infection risk regardless of virus type. [ABSTRACT FROM AUTHOR]

Relative humidity could be a predominant parameter for thermal comfort. The existing ventilation performance index regarding thermal comfort, i.e. , the Effective Draft Temperature (EDT), does not account for the effect of relative humidity on thermal comfort. This study proposes a novel ventilation performance index, i.e. , the Effective Moisture Temperature (EMT), to account for the effects of air temperature and relative humidity on thermal comfort. The proposed EMT is defined as an analogy of the EDT and is quantified by the theoretical analysis of the thermal neutrality, boundaries of thermal comfort zone, and equivalent transfer between the relative humidity and air temperature. The proposed EMT is tabulated for practical convenience under cooling and heating scenarios with different thermal comfort requirements. The results based on Monte Carlo simulations and ASHRAE Global Thermal Comfort Database II show that for the low air movement conditions, the accuracy of the original EDT is 23.8%–88.0%, while the accuracy of the proposed EMT is 98.6%–99.5%. This study further develops the Effective Draft and Moisture Temperature (EDMT) for elevated air movement by integrating the EMT and the cooling effect of air movement. For the elevated air movement conditions, the accuracy of the extended EDT is 84.1%–95.5%, while the accuracy of the proposed EDMT is 96.7%–99.2%. The proposed EMT and EDMT contribute to developing thermally comfortable built environments. • EMT considers effects of air temperature and relative humidity on thermal comfort. • EMT is tabulated for cooling/heating with different thermal comfort requirements. • EDMT is developed from EMT for elevated air movement. • EMT largely improves thermal comfort evaluation with accuracy of 98.6%–99.5%. • EDMT largely improves thermal comfort evaluation with accuracy of 96.7%–99.2%. [ABSTRACT FROM AUTHOR]

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Computational fluid dynamics models have been developed to predict airborne exposure to the SARS‐CoV‐2 virus from a coughing person in a mechanically ventilated room. The models were run with three typical indoor air temperatures and relative humidities (RH). Quantile regression was used to indicate whether these have a statistically significant effect on the airborne exposure. Results suggest that evaporation is an important effect. Evaporation leads to respiratory particles, particularly those with initial diameters between 20 and 100 μm, remaining airborne for longer, traveling extended distances and carrying more viruses than expected from their final diameter. In a mechanically ventilated room, with all of the associated complex air movement and turbulence, increasing the RH may result in reduced airborne exposure. However, this effect may be so small that other factors, such as a small change in proximity to the infected person, could rapidly counter the effect. The effect of temperature on the exposure was more complex, with both positive and negative correlations. Therefore, within the range of conditions studied here, there is no clear guidance on how the temperature should be controlled to reduce exposure. The results highlight the importance of ventilation, face coverings and maintaining social distancing for reducing exposure. [ABSTRACT FROM AUTHOR]

In this study, we used hourly observations to investigate the cooling effect of summer rainfall on surface air temperature (Ta) in a subtropical area, Guangdong province, South China. Data were categorized step-by-step by rainfall system (convection, monsoon, and typhoon), daily rainfall amount, and relative humidity (RH) level. Moreover, the average hourly Ta variation due to solar radiation was removed from all observations before statistical analysis. The results showed that the linear relationship between hourly Ta variation and rainfall intensity did not exist. However, the cooling effect of rainfall on Ta variation was dominant. In addition, convective rainfall does cause a greater temperature drop than the other two rainfall systems. After further partitioning all samples by RH level preceding the rainfall, the relationship between hourly Ta variation and rainfall intensity became distinctive. When RH was below 70%, rainfall-induced cooling became more substantial and scaled linearly with event intensity, but when RH exceeded 70%, the rainfall cooling effect was generally restrained by the RH increase. A strong correlation between hourly Ta variation and RH level preceding the rainfall suggests the importance of RH on the rainfall cooling effect. [ABSTRACT FROM AUTHOR]

This study determined the effects of increasing ambient temperature (T) at different relative humidity (RH) and air velocity (AV) levels on the physiological and productive responses of dairy cows. Twenty Holstein dairy cows were housed inside climate-controlled respiration chambers, in which the climate was programmed to follow a daily pattern of lower night and higher day T with a 9°C difference, excluding effects from sun radiation. Within our 8-d data collection period, T was gradually increased from 7 to 21°C during the night (12 h) and 16 to 30°C during the day (12 h), with an incremental change of 2°C per day for both nighttime and daytime T. During each research period, RH and AV were kept constant at 1 of 5 treatment levels. A diurnal pattern for RH was created, with lower levels during the day and higher levels during the night: low (RH_l: 30–50%), medium (RH_m: 45–70%), and high (RH_h: 60–90%). The effects of AV were studied during the day at 3 levels: no fan (AV_l: 0.1 m/s), fan at medium speed (AV_m: 1.0 m/s), and fan at high speed (AV_h: 1.5 m/s). Effects of short and long exposure time to increasing T were evaluated by collecting data 2 times a day: in the morning [short: 1 h (or less) − exposure time] and afternoon (long: 8 h − exposure time). The animals had free access to feed and water and both were ad libitum. Respiration rate (RR), rectal temperature (RT), skin temperature (ST), dry matter intake, water intake, milk yield, and composition were measured. The inflection point temperatures (IPt) at which a certain variable started to change were determined for the different RH and AV levels and different exposure times. Results showed that IPt under long exposure time for RR (first indicator) varied between 18.9 and 25.5°C but was between 20.1 and 25.9°C for RT (a delayed indicator). The IPt for both RR and RT decreased with higher RH levels, whereas IPt increased with higher AV for RR but gave a minor change for RT. The ST was positively correlated with ambient T and ST was not affected by RH but significantly affected by AV. For RR, all IPt was lower under long exposure time than under short exposure time. The combination of higher RH levels and low AV level negatively affected dry matter intake. Water intake increased under all treatments except RH_l-AV_l. Treatment RH_h-AV_l negatively affected milk protein and fat yield, whereas treatments RH_m-AV_m and RH_m-AV_h reduced milk fat yield. We concluded that RH and AV significantly affected the responses of RR, RT, ST, and productive performance of high-producing Holstein cows. These responses already occurred at moderate ambient T of 19 to 26°C. [ABSTRACT FROM AUTHOR]

Forests are one of the most important sources of negative oxygen ions (NAIs). NAIs have been recognized as beneficial for both physical and mental well–being, and higher concentrations of NAIs have been associated with improved health. However, the environmental factors that predominantly influence NAI concentration and their relationship with NAIs remain uncertain. This study aims to investigate the dominant factors and their impact on NAI concentration by observing NAIs and various environmental factors in two different environments (natural forest and urban forest) in the Beijing region over a one–year period. Through our investigation, we aimed to identify the key factor as well as other influential variables affecting NAI concentration. Our analysis encompassed the examination of dynamic concentration changes over multiple time scales, revealing uniform trends in both forest types. Notably, natural forests consistently demonstrated higher NAI concentration across these time scales, attributable to greater vegetation density and the stability of the forest microenvironment. By utilizing regression, correlation analysis, and structural equation analysis, we determined that relative humidity (RH) has the most significant effect on NAI concentration. Notably, both NAI concentration and RH displayed similar patterns across multiple time scales. When considering hourly average daily variation, the lowest values for both NAI concentration and RH were observed at noon, followed by an increase that persisted throughout the night. Seasonal average variation showed that both NAI concentration and RH peaked in the summer, followed by autumn. In terms of daily average annual variation, summer exhibited more days with high NAI concentration and high RH, which can be attributed to the increased rainfall during that season. Rainy weather was found to contribute to higher NAI concentration and RH levels. Furthermore, our findings revealed that on a daily scale, high RH and high NAI concentration occurred more frequently under conditions of high air temperature and low wind speed. However, the air quality index demonstrated only a minor effect in urban forest, while net radiation exhibited no significant influence on NAI concentration and RH. The fitted equations and trends of the aforementioned environmental factors with NAI concentration and RH were found to be comparable. The path analysis further corroborates these conclusions. The findings of this study indicate that RH is the primary factor driving the fluctuations in NAI concentration across various time scales, including hourly, daily, and seasonal variations. The study revealed that wind speed indirectly impacts NAI concentration by modulating RH. In contrast, air temperature influences NAI concentration both indirectly through RH and directly. The environmental factors affecting NAI concentration in the two types of forests are similar, but the degrees vary; in urban forests, wind speed, air quality index, and RH are slightly higher, while in natural forests, air temperature is slightly higher. This discovery further enhances our understanding of the underlying mechanisms and dynamic changes in NAI concentration within urban forests and natural forests. Moreover, it confirms the reliability and effectiveness of using RH as an indicator to monitor changes in NAI concentration over time. [ABSTRACT FROM AUTHOR]

The design and materials used for large-caliber ammunition containers significantly effect on its shelf-life, safety and functional reliability during the handling and storage process. All ammunition containers should protect the ammunition in the required operating environment during extreme weather conditions, in terms of water resistance and protection from corrosion and fungi, and ammunition inside of the container needs to withstand all shocks caused during handling and transport. There are significant differences in the design, construction and materials used for the containers of NATO concept and ammunition containers of Eastern concept. The basic differences between these two concepts are reflected in the degree of protection of ammunition during extreme changes in temperature and relative humidity in ammunition storage and inside of containers. The NATO concept of ammunition container is consisted of outer and inner lining, where outer lining is usually made of wood or steel sheet. The inner lining protects the contents from the influence of environmental parameters (temperature, relative humidity). The Eastern concept of a large-caliber ammunition containers usually does not have an inner lining. The aim of the experimental research carried out in four different containers, was to identify and analyze the degree of variations in temperature and relative humidity in ammunition containers of NATO and Eastern concept during the storage, depending on the change of seasons. Using a Tiny tag Plus TGIS-1580 data logger, the changes in temperature and relative humidity were measured, inside and outside of ammunition magazine, inside the ammo box and inside of fiber container. Experimental research showed large influence of the design of outer and inner lining of ammunition containers on the variation of environmental parameters. Since the ammunition is expensive and tends to have a longer shelf life, it is necessary to implement NATO concept of ammunition containers on ammunition packaging of the Eastern concept. [ABSTRACT FROM AUTHOR]

In Egypt, Lake Manzala is the largest and the most productive lake of northern coastal lakes. In this study, the continuous measurements data of the Real Time Water Quality Monitoring stations in Lake Manzala were statistically analyzed to measure the regional and seasonal variations of the selected water quality parameters in relation to the change of air temperature and relative humidity. Simple formulas are elaborated using the DataFit software to predict the selected water quality parameters of the Lake including pH, Dissolved Oxygen (DO), Electrical Conductivity (EC), Total Dissolved Solids (TDS), Turbidity, and Chlorophyll as a function of air temperature, relative humidity and quantities and qualities of the drainage water that discharge into the lake. An empirical positive relation was found between air temperature and the relative humidity and pH, EC and TDS and negative relation with DO. There is no significant effect on the other two parameters of turbidity and chlorophyll. [ABSTRACT FROM AUTHOR]

In underground confined spaces with a crowded population, the thermal environment will be hot-humid and occurred with high CO 2 concentration. Investigating the combined effect of increased temperature, relative humidity and CO 2 concentration on human responses is important for confined spaces. In this paper, 32 subjects were exposed to different combinations of air temperature ( T a ), relative humidity ( RH ) and CO 2 concentrations in an underground climate chamber, with thermal response, physiological response and acute health symptoms being investigated. Results show that: at a T a of 28 °C, RH of 65% and CO 2 level of 12,000 ppm, thermal sensation votes (TSV) and thermal acceptability (TA) did not significantly changed, while a significant change was recorded with a RH of 85%. When CO 2 concentration increased to 8000 ppm, the subjects' perceived air quality acceptability significantly decreased at T a of 33 °C, however it did not significantly change at T a of 28 °C and RH of 65%. Maximum mean skin temperature and wetness difference did not exceed 0.3 °C and 0.15 units between the different exposure conditions, respectively. Significant changes of headaches were observed when CO 2 concentrations increased to 12,000 ppm at a RH of 85%, but the difference was not statistically significant at a RH of 65%. This indicated that the combined effects of high T a , RH and CO 2 concentration lead to different human responses. [ABSTRACT FROM AUTHOR]

The northernmost Limpopo Province is located in one of the warmest regions of South Africa, where the agricultural sector is prone to heat stress. The aim of this study was to explore air temperature and relative humidity trends for the region, which have implications for agricultural adaptation and management (amongst other sectors). In particular, we investigated seasonal, annual and decadal scale air temperature and relative humidity changes for the period 1950-2016. Positive temperature trends were recorded for this period, averaging +0.02 °C/year, with the strongest changes observed in mean maximum summer temperatures (+0.03 °C/year). Interannual temperature variability also increased over time, especially for the period 2010-2016, which presents probability densities of <50% for minimum temperatures. Positive relative humidity trends (+0.06%/year) were also recorded for the period 1980-2016, but proved to be the least predictable weather parameter, with probability densities of <0.5% across seasons for the study period. Considering the substantial interannual variability in temperature and relative humidity, there is clear increased risk for the agricultural sector, particularly for small-scale farmers who generally have limited capacity to adapt. Climate science focusing on the southern African region should continue to establish the impact of climate change and variability on specific small-scale farming systems and enterprises, with recommendations for strategic adaptation based on up-to-date evidence. [ABSTRACT FROM AUTHOR]

Relative humidity (RH) is one of the key variables for understanding the water, energy, and carbon exchange between the Earth and the atmosphere. Traditional methods for deriving RH from remotely sensed data usually require ground meteorological observations or are limited to clear-sky conditions, thereby making it a significant challenge to obtain spatially complete RH under all-sky conditions, especially over the regions with sparse meteorological instruments for observation. To this end, a new approach for deriving all-sky RH entirely based on Moderate Resolution Imaging Spectroradiometer (MODIS) data was proposed in the present study. Two key assumptions in the approach under cloudy conditions are that the actual water vapor is linearly related to the total precipitable water vapor (PWV) and that air temperature is linearly related to land surface temperature (LST). Results from a total of 30 AmeriFlux stations proved the aforementioned assumptions based on MODIS data collected over a study period of three years from 2009 to 2011. For different aridity conditions, RH retrieval revealed reasonable accuracy with a root-mean-square error (RMSE) of approximately 15.3% over an arid and semiarid region, whereas a comparable RMSE of 17.0% was obtained over a humid area. Further results also indicated that the aforementioned linear relationships were generally temporally stable, thereby indicating that the proposed method can be used to obtain all-sky RH at a regional or global scale entirely based on MOD06_L2-derived LST and MOD05_L2-derived PWV data given that the assumed linear relationships can be easily determined by historical MOD07_L2-derived atmospheric profiles. [ABSTRACT FROM AUTHOR]

It is common that extraterrestrial solar radiation Ra value lessen due to the interaction with atmosphere components to result a net solar radiation Rn value about one third of Ra for most measurements on earth. Net solar radiation had major impact on air temperature (To) value statement. So, its estimation is crucial for analyzing the interaction of (atmosphere-vegetation-soil). Many methodologies available for this aim directly (with radiometer) or indirectly (with air temperature-based formula or soil plus air temperatures-based formula). The peak influences of global warming phenomenon were in eighties decade of the last century, yielding Iraq Rn rates to get climax after that Rn rates behaved in geographical based style, so those rates raised in middle and south regions of Iraq, and descending in its northern parts. The reason (as demonstrated in this research) was the spatial correlation in a reverse manner with RH rates all over Iraq. [ABSTRACT FROM AUTHOR]

Every autumn, low levels of wheel–rail contact adhesion caused by leaves on the railhead surface are reported by train drivers. These incidents cause problems for the safety and regularity of rail traffic and occur predominantly at the beginning and end of the day when high humidity levels are achieved. At those moments the air temperature reaches the dew point temperature creating moisture on the railhead and oxides which react chemically with dead leaves found on the railhead surface. This article presents the results of a test campaign performed on a ring-on-disc tribometer with the aim of reproducing and studying the development of a loss of adhesion at an imposed slip rate. This type of tribometer enables a realistic approximation of the tribological circuit of a rail–wheel contact. Several samples of pollution responsible for adhesion losses were collected on the French railway network during fall and reproduced in a laboratory on a tribometer under imposed relative humidity and slip conditions. The results indicate the presence of reproducible phenomena modulated by variations in hygrometry and imposed slip rates. The decrease in hygrometry of the external third bodies introduced into the contact is at the origin of the generation of debris from the first bodies in contact. This presence of wear debris is reflected by an increase of the power dissipated by friction. Conversely, increasing the hygrometry decreases the ability of the third body to raise adhesion levels on contact and reduces the generation of debris from the first bodies. The results obtained from the analysis of the force and power quantities related to the contact reproduced in the laboratory allow the authors to confirm that the presence of water has a significant effect on the mechanical and physico-chemical evolution of the adhesion of a rail–wheel contact polluted by a third external (leaf-like) body. [ABSTRACT FROM AUTHOR]

Monitoring and predicting the climatic phenomenon are the major global concern because of its devasting effects on people's lives and their environments. As a result of this, there is a need to understand the natural processes that control the dynamic evolution of the climatic phenomenon. Air temperature and relative humidity data collected from Nsukka station by the Centre for Atmospheric Research (CAR), measured in 5 minutes time steps from 1st January till 31st December, 2012 have been analysed. Dew point temperature was calculated from the actual readings of air temperature and relative humidity using appropriate empirical relation. In this paper, Average Mutual Information (AMI), False Nearest Neighbour (FNN) and Lyapunov Exponent methods were used to study changes and transitions in the dynamics of these meteorological parameters or temporal deviations from their overall dynamical regimes. The results show that the dynamic model needed to describe the data has 4-5 dimensions for air temperature, 4-6 for relative humidity and 4-5 for dew point temperature. Positive and negative Lyapunov exponents were observed in the air temperature, relative humidity and dew point temperature time series. This indicates that there exists periodicity inherent in the chaotic behaviour of these meteorological time series, causing a transition from chaoticity (positive Lyapunov exponent) to periodicity (negative Lyapunov exponent) and thereafter to chaoticity (positive Lyapunov exponent). The results, therefore, provide additional information about the climate transitions, maximum predictability and also, for formulating a weather prediction model. [ABSTRACT FROM AUTHOR]

In this paper two numerical stochastic models of the joint non-stationary time-series of air temperature, relative humidity and atmospheric pressure are proposed. The first model is based on an assumption that real weather processes are periodically correlated random processes with a period equal to 1 day. This assumption takes into account the diurnal variation of real meteorological processes, determined by the day/night alternation. Within the framework of the second model, real weather processes are considered as non-stationary random processes. The input parameters of both models (one-dimensional distributions and correlation structure of the joint time-series) are determined from the data of long-term real observations at weather stations. The results of the models verification are presented. [ABSTRACT FROM AUTHOR]

The Mars 2020 mission rover "Perseverance", launched on 30 July 2020 by NASA, landed successfully 18 February 2021 at Jezero Crater, Mars (Lon. E 77.4509° Lat. N 18.4446°). The landing took place at Mars solar longitude Ls = 5.2°, close to start of the northern spring. Perseverance's payload includes the relative humidity sensor MEDA HS (Mars Environmental Dynamics Analyzer Humidity Sensor), which operations, performance, and the first observations from sol 80 to sol 410 (Ls 44°–210°) of Perseverance's operations we describe. The relative humidity measured by MEDA‐HS is reliable from late night hours to few tens of minutes after sunrise when the measured humidity is greater than 2% (referenced to sensor temperature). Data delivered to the Planetary Data System include relative humidity, sensor temperature, uncertainty of relative humidity, and volume mixing ratio (VMR). VMR is calculated using the MEDA‐PS pressure sensor values. According to observations, nighttime absolute humidity follows a seasonal curve in which release of water vapor from the northern cap with advancing northern spring and summer is visible. At ground level, frost conditions may have been reached a few times during this season (Ls 44°–210°). Volume mixing ratio values show a declining diurnal trend from the midnight toward the morning suggesting adsorption of humidity into the ground. Observations are compared with an adsorptive single‐column model, which complies with observations and confirms adsorption. The model allows estimating daytime VMR levels. Short‐term subhour timescales show large temporal fluctuations in humidity, which suggest vertical and spatial advection. Plain Language Summary: The Mars 2020 mission rover "Perseverance" landed successfully on 18 February 2021 at Jezero Crater, Mars. The rover's payload includes a versatile instrument suite which includes a relative humidity sensor, whose observations for the first 410 Martian days are described here. The observations show how the lowest level of atmosphere is generally dry but still exceeding saturation is feasible because of cold nights. Sensor operations and accuracy estimates are presented. Relative humidity together with MEDA pressure and air temperature observations allow calculating absolute water vapor content of air at the sensor level at nighttime. Humidity observations are also compared with models describing water vapor adsorption and desorption into and out from soil. The results show how atmospheric humidity at the rover's site experiences large subhour variability. Humidity observations help to understand interchange of humidity between the soil and the atmosphere. Water is mandatory for life, such as on earth, thus understanding these water cycle processes better are important for evaluating possibilities of past and current habitability of Mars. Perseverance is also collecting samples which maybe returned to Earth one day. Knowledge of the conditions at the times when samples were collected maybe useful. Key Points: Humidity observations in Mars by M2020 Perseverance rover during the first 410 sols of operation are shown and discussedHumidity sensor MEDA‐HS operations and sensor accuracy are explainedAdsorptive single column model is tested and compared with humidity observations [ABSTRACT FROM AUTHOR]

This study quantifies how far snow can fall into the melting layer (ML) before all snow has melted by examining a combination of in situ observations from aircraft measurements in Lagrangian spiral descents from above through the ML and descents and ascents into the ML, as well as an extensive database of NOAA surface observer reports during the past 50 years. The airborne data contain information on the particle phase (solid, mixed, or liquid), population size distributions and shapes, along with temperature, relative humidity, and vertical velocity. A wide range of temperatures and ambient relative humidities are used for both the airborne and ground-based data. It is shown that an ice-bulb temperature of 0°C, together with the air temperature and pressure (altitude), are good first-order predictors of the highest temperature snowflakes can survive in the melting layer before completely melting. Particle size is also important, as is whether the particles are graupel or hail. If the relative humidity is too low, the particles will sublimate completely as they fall into the melting layer. Snow as warm as +7°C is observed from aircraft measurements and surface observations. Snow pellets survive to even warmer temperatures. Relationships are developed to represent the primary findings. [ABSTRACT FROM AUTHOR]

The automatic tool changer (ATC) in computerized numerical control (CNC) milling machine often uses pneumatic dynamic sources. Friction in the pneumatic cylinder affects the ATC's stopping position; this friction depends on many factors, including the air environment's relative humidity and temperature. This paper presents the results of research on the effects of relative humidity (RH) and air temperature (T) on the stopping position of an ATC using a pneumatic cylinder. Studies were conducted at temperatures of 1 5 ∘ C, 3 2 ∘ C and 4 9 ∘ C and relative humidity values of 51%, 75% and 99% for different speeds of the pneumatic cylinder (30, 50 and 100 mm/s). The results show that when the humidity increases from 51% to 99% and the temperature increases from 1 5 ∘ C to 4 9 ∘ C, the friction force decreases. The friction force is related to the relative humidity and temperature of the air. Thus, the deviation of the ATC's stopping position depends on the relative humidity and temperature of the area under investigation. [ABSTRACT FROM AUTHOR]

To investigate the effect of relative humidity percentage on heat transfer and distribution of droplets in the condensation phenomenon, a test device with the ability to provide and control different environmental conditions was made, and therefore, the hydrophilic (copper) and hydrophobic (Teflon coating on copper) surfaces were measured under controlled environmental conditions. In all the tests, the inlet air flow rate, inlet air temperature, air temperature reaching the test surface, water temperature, water surface height, and test surface temperature were kept constant at specific values using PID control. Each test's relative humidity values of 80, 88, and 96% have been determined and controlled. The results of the transient investigation of heat transfer show that it takes time for the condensation phenomenon to occur, and the higher the surface hydrophilicity and relative humidity, the shorter this time will be. Also, the average heat transfer for 60 minutes was calculated. It showed that the average heat transfer coefficient increases with increasing humidity. Under the same environmental conditions, the heat transfer coefficient on hydrophilic surfaces is higher than on hydrophobic ones. In the graphical analysis of the droplet size, it has been observed that the most oversized droplets on hydrophilic surfaces at relative humidities of 88 and 96% are in the hydraulic diameter range of 0.35 to 0.4, and on hydrophobic surfaces are at relative humidities of 80 and 88% in the hydraulic diameter range of 0.2 to 0.25 mm. [ABSTRACT FROM AUTHOR]

As soil water deficit limits crop growth and yield, yet the combined effects of soil drying and elevated vapour pressure deficit (VPD) of the air on crop performance have not been fully understood. The objective of this study was to investigate the interactive effects of soil drying and elevated VPD on growth and physiology of barley seedlings grown under controlled climates. The plants were grown in four separate climate chambers with two air temperature (T, 20 and 30°C) and relative humidity (RH: 60 and 75%) levels, respectively, resulting in four VPD levels, viz. VPD1 (0.59 kPa, 20°C + 75% RH), VPD2 (0.94 kPa, 20°C + 60% RH), VPD3 (1.06 kPa, 30°C + 75% RH) and VPD4 (1.70 kPa, 30°C + 60% RH). Since the 4th leaf stage, the plants were subjected to two irrigation treatments, namely well‐watered and drought‐stressed. The results showed that soil water deficits significantly limited leaf gas exchange rates and reduced shoot dry biomass (DMshoot) and water consumption (WU), whereas increased leaf ABA concentration ([ABA]leaf) and plant water‐use efficiency (WUE) at each VPD level. Plants grown under VPD1 and VPD2 had greater net photosynthetic rate (An) and stomatal conductance (gs) while lower transpiration rate (Tr) than those grown under VPD3 and VPD4 at both irrigation treatments. Besides, elevated VPD resulted in an increased daily transpiration per leaf area (DT) and greater soil water threshold at which DT starts to decrease. Interactions between VPD and drought were significant where the effects of drought on An, relative water content (RWC), DMshoot and WUE were more severe at VPD3 and VPD4 than that at VPD1 and VPD2. When disentangling the effects of T and RH, the results showed that it was T rather than RH influenced the An, stomatal density and RWC, whereas the combined effect of T and RH, that is VPD, was significant in affecting gs, Tr, [ABA]leaf, leaf area, DMshoot, WU and WUE, where WUE was negatively correlated with VPD. Therefore, it is essential to dissect the effects of T and RH when analysing their combined effects with soil water deficits on crop performance in a future warmer and drier climate. [ABSTRACT FROM AUTHOR]

The cooling and humidifying effects of urban parks are an essential component of city ecosystems in terms of regulating microclimates or mitigating urban heat islands (UHIs). Air temperature and relative humidity are two main factors of thermal environmental comfort and have a critical impact on the urban environmental quality of human settlements. We measured the 2-m height air temperature and relative humidity at the Beijing Olympic Park and a nearby building roof for more than 1 year to elucidate seasonal variations in air temperature and relative humidity, as well as to investigate the outdoor thermal comfort. The results showed that the lawn of the park could, on average, reduce the air temperature by (0.80±0.19)°C, and increase the relative humidity by (5.24±2.91)% relative to the values measured at the building roof during daytime. During the nighttime, the lawn of the park reduced the air temperature by (2.64±0.64)°C and increased the relative humidity by (10.77±5.20)%. The park was cooler and more humid than surrounding building area, especially in night period (more pronounced cooling with 1.84 °C). Additionally, the lawn of the park could improve outdoor thermal comfort through its cooling and humidifying effects. The level of thermal comfort in the park was higher than that around the building roof for a total of 11 days annually in which it was above one or more thermal comfort levels (average reduced human comfort index of 0.92) except during the winter. [ABSTRACT FROM AUTHOR]

In this work we present results from an intercomparison study between two CS500 temperature-relative humidity sensors and a brand new sonic anemometer/gas analyzer (Campbell Scientific Instruments - CSI IRGASON). The objective of the intercomparison was an upcoming micrometeorological experiment. For the intercomparison, all sensors were positioned at the same height over the water surface, at the Rio Verde reservoir, in the vicinity of Curitiba, PR, Brazil. The compared variables were air temperature and relative humidity. The CS500 air temperatures were compared to those from a CSI 107 temperature sensor operates with the IRGASON; for the relative humidity comparisons, water vapor concentration measured by the IRGASON was converted to an equivalent relative humidity. Standard linear correlations were calculated. [ABSTRACT FROM AUTHOR]

The atmosphere is an undeniable source of error for any geodetic instruments. Surveyors require to have an accurate approximation of distance measurements in order to accurately determine the 3D coordinate of points. Electronic Distance Measurements (EDMs) are employed to measure accurate range to the target. They are typically functioning by laser in the domain of light or near infrared of electromagnetic spectrum (EM). Snell's law has proved propagating wave through passing the different layers of atmosphere is deviated. This phenomenon is called the refractivity of wave. This deviation is introduced by different intersection between the beam and the object surface at different epochs of atmospheric change. By possessing the knowledge of group refractive index, it is possible to estimate the value of correction in ppm for measured distances caused by the variations in atmospheric elements. The changes in three components of air, temperature, pressure and humidity, in this study will be considered. [ABSTRACT FROM AUTHOR]

Drought stress often occurs concurrently with heat stress, yet the interacting effect of high vapor pressure deficit (VPD) and soil drying on the physiology of potato plants remains poorly understood. This study aimed to investigate the physiological and growth responses of potatoes to progressive soil drying under varied VPDs. Potato plants were grown either in four separate climate-controlled greenhouse cells with different VPD levels (viz., 0.70, 1.06, 1.40, and 2.12 kPa, respectively) or under a rainout shelter in the field. The VPD of each greenhouse cell was caused by two air temperature levels (23 and 30 °C) combined with two relative humidity levels (50 and 70%), and the VPD of the field was natural conditions. Irrigation treatments were commenced three or four weeks after planting in greenhouse cells or fields, respectively. The results indicated that soil water deficits limited leaf gas exchange and shoot dry matter (DMshoot) of plants while increasing the concentration of abscisic acid (ABA) in the leaf and xylem, as well as water use efficiency (WUE) across all VPD levels. High VPD decreased stomatal conductance (gs) but increased transpiration rate (Tr). High VPD increased the threshold of soil water for Tr began to decrease, while the soil water threshold for gs depended on temperature due to the varied ABA response to temperature. High VPD decreased leaf water potential, leaf area, and DMshoot, which exacerbated the inhibition of soil drying to plant growth. Across the well-watered plants in both experiments, negative linear relationships of gs and WUE to VPD and positive linear relations between Tr and VPD were found. The results provide some novel information for developing mechanistic models simulating crop WUE and improving irrigation scheduling in future arid climates. [ABSTRACT FROM AUTHOR]