Humidity Distribution Research Articles

Classification and characteristic analysis of the clouds and dust in a dust-carrying precipitation process based on multi-source remote sensing observations

A dust-carrying precipitation event that took place on May 11, 2020 in North China was observed by remote sensing methods including a micropulse lidar (MPL), millimeter-wavelength cloud radar (MMCR) and microwave radiometer from Yanjiaping (YJP) Station, which is the center of the transmission path of this dust storm, and it is the only super station capable of vertical observation of aerosols, clouds and precipitation in North China. The study researched the macro and microphysical characteristics of clouds and sand dust, as well as the possible impact of sand dust on clouds. It is found that dust has a great influence on the CBH measurement of ceilometer but little on the MMCR. The normalized relative backscatter (NRB) and depolarization ratio (DR) of the MPL were comparatively analyzed in terms of the mass concentration of PM10, revealing that the mass concentration of PM10 is linearly positively correlated to the NRB, with the correlation coefficient up to 0.9273. It was also discovered that the 100 μg/m3 is a critical point for the mass concentration of dust particles, and when the PM10 was greater than 100 μg/m3, the DR would fluctuate within a narrow range of 0.32–0.38. A classification method that could be used to distinguish among clear sky, non-dust aerosols, clouds, dust, and cloud-dust mixing zones was proposed. Based on the classification results, the immersion freezing process that might occur in the cloud-dust mixing area was analyzed using Z-LDR and V-SW by reference to the vertical distribution of temperature and humidity.

Influences of cooking and storage on γ-aminobutyric acid (GABA) content and distribution in mung bean and its noodle products

The γ-aminobutyric acid (GABA) content and distribution of mung bean (MB), heat and relative humidity treated MB (HRH-MB) under different cooking and storage conditions were investigated. The quality characteristics of noodles prepared by MB and HRH-MB were evaluated. Results showed that black MB varieties presented a higher average GABA content under HRH treatment than that of green MB varieties. Soaking significantly increased the GABA content of MB (P < 0.05), but, 58.78% of GABA in HRH-MB were distributed in the soaking solution. After cooking, although the GABA of HRH-MB had a slightly degradation, its content was higher than MB. With the increase of storage time, the GABA content in MB increased initially, followed by a decrease, whereas a slower reduction was observed on HRH-MB. Besides, compared with the mixed MB-wheat flour and noodles, the pasting properties of mixed HRH-MB-wheat flour, the color and texture properties of mixed HRH-MB-wheat noodles were improved and closer to wheat flour and noodles, respectively. Furthermore, the mixed HRH-MB-wheat noodles exhibited the highest GABA content (16.56 mg/100 g DW) after cooking. Therefore, HRH-MB may be an ideal material for enhancing GABA and improving the quality characteristic of MB-based foods.

On-site measurement and numerical investigation of thermal environment with different air distribution systems in ice arenas

It is important to strictly maintain the indoor thermal environment in ice arenas which have very different features to other commercial buildings. Separated air distribution system is widely used to create a dry and cold environment near the ice and a comfortable environment in the view stand. The warm and humid air from the view stand may lead to uneven temperature and humidity distribution in the rink, leading to extra energy consumption, even fog and frost on the ice. Unreasonable air supply in the ice rink zone will also make the spectators feel too cold and uncomfortable. Jet ventilation system is the most extensively used system in the ice rink zone. An innovative ground displacement ventilation system is proposed in the National Aquatics Centre, which will serve as the venue for the curling competition in the 2022 Beijing Winter Olympics. On-site measurement in the arena is carried out and computational fluid dynamics (CFD) simulation method is adopted in the present research. Measured thermal environment above the ice with different ventilation systems are compared and analysed. Result shows that the displacement ventilation system features a more obvious vertical stratification than jet ventilation system in this kind of large space buildings, and thus is more energy-efficient. A CFD model of the ice cube is setup and verified by measured data. The thermal environment in the ice rink with displacement ventilation under extreme condition is studied using the simulation method. The temperature and humidity in the ice field increases by 10.1 °C, 4.5 g/kg without air supply in the view stand, proving that the spectators in the view stand have a great impact on the thermal environment in the ice field.

Numerical simulation of the condensation process in high voltage switchgear based on the temperature and humidity distribution

The condensation on solid materials surface inside switchgear is an important reason threatening its safety and reliability. The formation of condensation is closely related to the temperature and humidity distribution inside the switchgear. A 3-D simplified finite element calculation model for the switchgear is established, including the bus bar, the wall bushing, the circuit breaker, the cables and other key components. Based on the electromagnetic-temperature-humidity multi-physical field coupling method, the temperature distribution inside the switchgear are calculated when the operating current flows through the bus-bar. Furthermore, the humidity diffusion process is also calculated when the relative humidity of external environment was 0.8, and the relative humidity inside the switchgear is obtained. The calculation results show that the surface humidity of the contact box of the circuit breaker is the highest whereas the temperature is the lowest, which is the location where the condensation is easy to occur.

Investigating the Causes and Impacts of Convective Aggregation in a High Resolution Atmospheric GCM

AbstractA ∼50 km resolution atmospheric general circulation model (GCM) is used to investigate the impact of radiative interactions on spatial organization of convection, the model's mean state, and extreme precipitation events in the presence of realistic boundary conditions. Mechanism‐denial experiments are performed in which synoptic‐scale feedbacks between radiation and dynamics are suppressed by overwriting the model‐generated atmospheric radiative cooling rates with its monthly varying climatological values. When synoptic‐scale radiative interactions are disabled, the annual mean circulation and precipitation remain almost unchanged, however tropical convection becomes less aggregated, with an increase in cloud fraction and relative humidity in the free troposphere but a decrease in both variables in the boundary layer. Changes in cloud fraction and relative humidity in the boundary layer exhibit more sensitivity to the presence of radiative interactions than variations in the degree of aggregation. The less aggregated state is associated with a decrease in the frequency of extreme precipitation events, coincident with a decrease in the dynamical contribution to the magnitude of extreme precipitation. At regional scales, the spatial contrast in radiative cooling between dry and moist regions diminishes when radiative interactions are suppressed, reducing the upgradient transport of energy, degree of aggregation, and frequency of extreme precipitation events. However, the mean width of the tropical rain belt remains almost unaffected when radiative interactions are disabled. These results offer insights into how radiation‐circulation coupling affects the spatial organization of convection, distributions of clouds and humidity, and weather extremes.

Performance of PEFC Under Different Gas-Mixing Conditions

Introduction For PEFCs’ grand-scale commercialization, their performance should be further improved. The performance of PEFC is the results of the distribution of the local current density and materials concentration, especially oxygen and water. In addition, the in-plane transport of gas in the gas diffusion layer (GDL), which is difficult to measure, affects the distribution of oxygen partial pressure and relative humidity (RH) by mixing the gas with different residence time. In this study, the distribution of local current density as well as oxygen partial pressure and RH was estimated by varying active area and gas velocity. Furthermore, two kinds of different gas channels, parallel and serpentine, were utilized to estimate the effect of gas mixing in the GDL. The concept of space time was used to discuss the effects of gas mixing in the perspective of chemical engineering. The results may provide a theory basis for cell design procedure. Theory The ORR kinetics can be expressed as Eq.1.-r SO = k gc p O (1)where -r SO is the oxygen consumption rate per active area [mol/(m2s)], p O is the local oxygen partial pressure [Pa] which was experimentally proved to be 1st-order to the reaction rate[1]. k gc represents the partial-pressure-based kinetics constant [mol/(Pa.m2s)] which is the function of cathode electromotive force and RH at a fixed temperature[2].PEFC has the gas-mixing behavior between plug flow reactor (PFR) and perfectly mixed flow reactor (CSTR), whose design equations can be written as Eqs.2 and 3.-r SO d(A/v 0) = C O0 Al dx O (2)-r SO (A/v 0) = C O0 Al x O (3)where A is the active area from the gas inlet [m2], v 0 is the inlet gas velocity [m/s], C O0 is the oxygen concentration in the inlet gas [mol/m3], Al is the cross-section area of a single gas channel [m2], and x O is the oxygen conversion. Experimental The membrane electrode assembly (MEA) with 10 mm thick catalyst layer and Nafion® ionomer and membrane (DuPont NR-212) was set up in a JARI-type cell. The polarization curves were measured with parallel and serpentine channels under different gas flow rates. The different areas of gaskets opening and GDLs were utilized to obtain different active areas, as shown in Fig. 1. The reactant gas was humidified in bubblers. The cell was operated at 80 °C and the pressure at the cell outlet was 1 atm. Results and Discussion Fig. 2 shows the experimental results of polarization curve. The integrated current per active area is higher in 4 cm2 active area comparing to 2 cm2 at high cell voltage in case of parallel channels, and vice versa at low cell voltage. Since the ORR-produced water humidifies the cell, which increases the activity of the catalyst, the current density near the outlet is higher than that near the inlet. When the current density is high enough, liquid water floods the cell, which causes the performance decrease. On the other hand, the polarization characteristics with different active areas are nearly the same in case of serpentine channels. Higher velocity in the gas channel promote the liquid water removal so that the flooding is not remarkable.Fig. 3 shows the relationship between oxygen conversion and area/velocity, which is proportional to the space time. The convex downward curve in case of the parallel channels indicates that the ORR in the cell behaves like an autocatalytic reaction in PFR. Whereas, the curve of the cell with serpentine channels is slightly convex upward, which infers the gas mixing in the cell is more remarkable, approaching to CSTR.As the oxygen conversion increasing, the water vapor partial pressure increases and the oxygen partial pressure decreases, so that a maximal reaction rate exists, as shown in Fig. 4. Therefore, a turning point of oxygen conversion exists, below which a gas channel working like CSTR e.g. serpentine channels should be chosen, and above which a gas channel working like PFR e.g. parallels channel should be chosen, as shown in Fig. 5. Conclusions The distribution of local current density and gas composition as well as gas mixing can be estimated by varying active area and gas velocity. The ORR in the cell with parallel channels can be regarded as an autocatalytic reaction in PFR. The gas mixing in the cell with serpentine channels is more remarkable than parallel channels. When the active area and gas flow rate are certain, an optimal gas channel which the gas-mixing character of is known can be selected in cell design. Acknowledgment This work was supported by the New Energy and Industrial Technology Development Organization (NEDO), Japan. Figure 1

In-situ measurement of humidity distribution and its effect on the performance of a proton exchange membrane fuel cell

Understanding the internal water distribution in proton exchange membrane fuel cell (PEMFC) is critical to the development of high-performance PEMFCs. In this study, the cathode flow field is divided into 9 areas, and the relative humidity under different conditions is measured in-situ by using microsensors embedded in the cathode flow field plate. Polarization curves are measured and electrochemical impedance spectroscopy is carried out under different conditions. The results show that the relative humidity has a significant effect on the internal resistance of PEMFCs. When the inlet gas is not humidified, too high of a temperature will lead to low relative humidity and membrane dehydration. Increasing pressure and cathode humidification can alleviate this problem. However, the relative humidity of the outlet area is close to 100% when the cathode back pressure is 100 kPa, and a too high relative humidity will result in flooding in the cathode channel. Moreover, the degree of corrosion of the carbon support in the catalyst is closely related to the water concentration in the cathode, and the water management downstream of the flow field is particularly important.

Climatology of Cloud‐Top Radiative Cooling in Marine Shallow Clouds

AbstractA one‐year’s worth of near‐global marine shallow single‐layer cloud top radiative cooling (CTRC) is derived from a radiative transfer model with inputs from the satellite cloud retrievals and reanalysis sounding. The mean cloud top radiative flux divergence is 61 Wm−2, decomposed into the longwave and shortwave components of 73 and −11 W m−2, respectively. Equatorward of 30°N/S, the CTRC is largely a reflection of free‐atmospheric specific humidity distribution: a dry atmosphere enhances CTRC by reducing downward thermal radiation. Consequently, the cooling minimizes in the “wet” tropics and maximizes in the “dry” eastern subtropics. Poleward of 30°N/S, the CTRC decreases slightly due to the colder clouds that emit less effectively. The CTRC exhibits distinctive seasonal cycles with stronger cooling in the winter and has amplitudes of order 10–20 Wm−2 in stratocumulus‐rich regions. The datasets were used to train a machine‐learning model that substantially speeds up the retrieval.

Performance of PEFC Under Different Gas-Mixing Conditions

For PEFCs’ grand-scale commercialization, their performance should be further improved. The performance of PEFC is the results of the distribution of local current density and materials concentration, especially oxygen and water. In addition, the in-plane transport of reactant gas in the gas diffusion layer (GDL), which is difficult to measure, affects the distribution of oxygen partial pressure and relative humidity (RH) by mixing the gas with different residence time. In this study, the distribution of local current density as well as oxygen partial pressure and RH was estimated by varying active area and gas flow rate. Furthermore, two kinds of different gas channels, parallel and serpentine, were utilized to estimate the effect of gas mixing in the GDL. The concept of space time was used to discuss the effects of gas mixing in the perspective of chemical engineering. The results may provide a theory basis for a cell design procedure.

Study on pollution characteristics and influencing factors of gaseous pollutants: Case study of a naturally ventilated commercial underground garage in Xi'an

The underground garage is generally in a closed or semi-closed space, where air pollutants discharged by motor vehicles are hard to diffuse, resulting in poor air quality and potential health risks. To get insight into the air quality in underground garages, field measurements were conducted to investigate the temperature, humidity, traffic volume, and temporal and spatial distributions of the concentrations of carbonic oxide (CO) and volatile organic compounds (VOCs) in a naturally ventilated commercial underground garage in Xi'an, China in this study. The influences of vehicle emissions and outdoor air quality on indoor air quality were also evaluated quantitatively. Results indicated that the concentrations of CO and VOCs showed obvious temporal and spatial distributions. The average concentrations of CO and VOCs (6.92 ± 2.3 mg/m3 and 5.87 ± 2.84 mg/m3) in autumn were higher than those (2.5 ± 1.21 mg/m3 and 3.34 ± 2.06 mg/m3) in winter. Their average concentrations near the entrance (3.52 ± 2.45 mg/m3 and 3.47 ± 2.17 mg/m3) were relatively lower than inside the garage (4.64 ± 3.02 mg/m3 and 4.79 ± 3.08 mg/m3). Besides, the concentration of CO exhibited a strong correlation with that of VOCs (p < 0.01). CO and VOCs concentrations were positively correlated with the humidity and negatively correlated with temperature in the garage (p < 0.01). Another important finding is that VOCs concentrations have exceeded the prescribed limit value (0.6 mg/m3), regulated by the “Indoor air quality standard of China”, suggesting that taking ventilation measures is necessary to reduce the concentrations of gaseous pollutants in the garage. This study can provide the scientific basis for the design and optimization of ventilation systems.

Optimization of 3D printer enclosure environment

Additive manufacturing has become a widely utilized process in industrial, academic, and household applications. Previous studies have demonstrated that non-optimum humidity conditions can adversely impact the print quality of parts printed from plastic filaments by changing their mechanical properties, such as elastic modulus and ultimate strength. This study utilized a computational fluid dynamics (CFD) approach and experimental testing to design a system that yields a more uniform humidity distribution in a 3-dimensional (3D) printer printing region. The study resulted in an optimized enclosure with significantly higher relative humidity (RH) uniformity in the print volume. The simulations predicted that the optimized enclosure would improve the uniformity by about 65%, while experimental testing pointed to even more significant improvement at about 75%. As a case study, tensile testing of 3D printed specimens made from NinjaFlex© filamenets under the optimum environmental conditions showed 11% higher ultimate strength and more elastic behavior than specimens printed using the baseline model.

Multiple Moist Climate Equilibrium States on Arid Rocky M-dwarf Planets: A Last-saturation Tracer Analysis

Abstract Terrestrial-type exoplanets orbiting nearby red dwarf stars (M dwarfs) are the first potentially habitable exoplanets suitable for atmospheric characterization in the near future. Understanding the stability of water in cold-trap regions on such planets is critical because it directly impacts transmission spectroscopy observations, the global energy budget, and long-term surface water evolution. Here we diagnose the humidity distribution in idealized general circulation model simulations of terrestrial-type exoplanets. We use the “tracer of last saturation” technique to study the saturation statistics of air parcels. We find that on synchronously rotating planets the water vapor abundance in the nightside upper troposphere depends weakly on planetary rotation, while more water vapor builds up in the nightside lower troposphere on fast-rotating planets. We then discuss how last-saturation statistics can elucidate the multiple moist climate equilibrium states on synchronously and asynchronously rotating arid planets. We show that the multiple moist climate states arise from the cold-trapping competition between the substellar upper atmosphere and cold surface regions. We find that fast synchronously rotating planets tend to trap surface water on the nightside as a result of their weak atmospheric and strong surface cold traps compared to the slow-rotating case. These results elucidate the nature of the water cycle on arid rocky exoplanets and will aid interpretation of atmospheric observations in the future.

Evaporation rate far beyond the input solar energy limit enabled by introducing convective flow

Solar-driven interfacial evaporation for desalination is regarded as one of the most promising technologies to relieve global freshwater scarcity due to its high efficiency, sustainability and low cost. However, the evaporation rate, as one of the decisive factors of the throughput of evaporative water, has been severely restricted due to heat loss and insufficient vapor diffusion in the conventional evaporators. Herein, we demonstrate that a carbon nanotubes (CNTs) and airlaid paper-based 3D wavy evaporator not only facilitates the double-surface evaporation, but also can effectively diffuse the suspended vapor assisted by the convective flow, so as to reverse the heat loss and continuously harvest additional energy for efficient evaporation. An evaporation rate as high as 5.55 kg m−2h−1 is achieved under one sun illumination coupled with convective flow of 5 m s−1, well beyond 278% of the input solar energy limit, presuming 100% solar-to-vapor energy conversion. More importantly, the 3D wavy evaporator can consistently evaporate for 24 h in the natural environment, with the outdoor evaporation up to 53.72 kg m−2 and no salt deposition. Furthermore, theoretical simulations of convective flow velocity and distribution, as well as relative humidity distribution, are remarkably compatible with experimental results. The realization of such a high evaporation rate provides a new inspiration for designing the around-the-clock and high-throughput evaporation system that can be practically applied.

Combined Effects of Ventilation and Irrigation on Temperature, Humidity, Tomato Yield, and Quality in the Greenhouse

Ventilation and soil moisture influence greenhouse cultivation. Experiments were conducted at Xinxiang Irrigation Research Base of the Chinese Academy of Agricultural Sciences, Henan Province, China, to identify how ventilation and irrigation affected the greenhouse microenvironment. To develop ventilation and irrigation protocols that increase crop yield and improve the quality of drip-irrigated tomatoes grown in the greenhouse, three ventilation modes (T1, T2, and T3) were developed by opening vents in different locations in a completely randomized pattern. T1 had open vents on the north wall and roof of the greenhouse. T2 had open vents on the north and south walls and the roof. T3 had open vents on the north and south walls. Three irrigation treatments (W1, W2, and W3) were designed based on the accumulated water surface evaporation (Ep) of a standard 20-cm evaporation pan. The irrigation quantities were 0.9×Ep (W1), 0.7×Ep (W2), and 0.5×Ep (W3). The spatial and temporal distributions of temperature and humidity were analyzed for different combinations of ventilation and irrigation to identify their effects on tomato yield and fruit quality. Major results were as follows: 1) In addition to solar radiation, ventilation had an important influence on Ep and, on a daily scale, ventilation had a significant effect on Ep (P &lt; 0.05). 2) Ventilation had a significant effect on indoor wind speed, but the effect varied during different growth stages. During the flowering and fruit setting stage, wind speed for T2 significantly differed from those of T1 and T3 (P &lt; 0.01). During the harvest stage, the three ventilation treatments had significantly different effects (P &lt; 0.01). A correlation analysis showed high correlation between T2 wind speed and T3 wind speed (R = 0.831), but low correlation between T2 wind speed and T1 wind speed (R = 0.467). 3) The effect of ventilation on greenhouse humidity and temperature was greater than the effect of irrigation. The differences in air temperature among various combined treatments of ventilation and irrigation were significant for the flowering and fruiting stages (P &lt; 0.05), but they were not significant for the late harvest stage (P &gt; 0.05). There were significant differences in humidity on sunny days (P &lt; 0.01), but no significant differences on cloudy or rainy days (P &gt; 0.05). Air temperature at 2 m was greater than canopy temperature, but humidity at 2 m was less than that at canopy level. 4) Irrigation water quantity was positively correlated with tomato yield and negatively correlated with the fruit quality indicators total soluble solids, vitamin C content, organic acid content, and soluble sugars content. Ventilation had an effect primarily during the harvest period; it had no significant effect on yield (P &gt; 0.05). However, it had a significant effect on vitamin C content and the sugar:acid ratio (P &lt; 0.01). The combination treatment of T2W2 is recommended as the optimal treatment for greenhouse tomatoes using drip irrigation to produce an optimal combination of crop yield and fruit quality. This study provides theoretical and technical support for the improvement of greenhouse climate control by optimizing greenhouse ventilation and irrigation techniques to promote tomato yield and improve fruit quality.

CFD Modeling of An Even-Span Greenhouse Dryer Under Natural and Forced Convection Modes

In this study an even-span greenhouse dryer was designed and simulated under two different drying modes, natural and forced convection modes. The CFD simulation was carried out taking into consideration the weather conditions at the mean day of January (winter season) in Marrakech, Morocco. CFD was employed to predict the air velocity, temperature and relative humidity distribution inside the greenhouse dryer. Under forced convection mode the air temperature and relative humidity were uniformly distributed inside the dryer. The highest air temperature and lowest air relative humidity was recorded at the mean hour of the simulation day, under forced convection mode. They were 37 °C and 12%, respectively. These results reveal that under forced convection mode the greenhouse exhibited significant thermal performances.

Temperature–Humidity Coupled Analysis in Battery Pack Based on Airflow Characteristics of Waterproof Breathable Valve

Abstract Waterproof breathable valves (WBV) are applied to the battery packs in electric vehicles due to their advantages of high efficiency waterproof and air pressure balance. With the continuity of mass transfer of WBV and uncertain thermal conditions, the dynamic thermal characteristic of the moisture inside the battery pack is difficult to obtain by experiments, especially the phase change of the moisture. To analyze WBV mass transfers to the temperature–humidity characteristic in the battery pack, this study presents a temperature–humidity coupling model of the battery pack based on the mass transfer characteristic of WBV. A mass transfer model of WBV is developed with the airflow mass transfer characteristic in air pressure difference. The proposed models verified the feasibility of dynamic thermal characteristic analysis with experiments. Finally, a practical case study on a battery pack is used to analyze dynamic characteristics of the temperature–humidity during idle and working. Using the coupling model and the WBV model, temperature–humidity distribution and the location and time attributes of moisture condensation in the battery pack are effectively obtained. The inner walls of the pack casing and the battery surface near WBV are condensation areas during environmental conditions changing.

A numerical study of the effects of ambient temperature and humidity on the particle growth and deposition in the human airway

A numerical study was conducted on the effects of ambient temperature and humidity on the transportation of sodium chloride particles (100 nm-1 μm) in a human airway model ranging from the nasal cavity to bronchi. A mucus-tissue structure was adopted to model the mass and heat transfer on the airway surface boundary. The temperature and humidity distributions of the respiratory flow were calculated and then the interaction between the particle and water vapor was further analyzed. It was predicted that the particle size grew to the ratio of 5–6 under subsaturation conditions because of hygroscopicity, which shifted the deposition efficiency in opposite directions on dependence of the initial particle size. However, the particles could be drastically raised to 40 times of the initial 100 nm diameter if the supersaturation-induced condensation was established, that was prone to occur under the cold-dry condition, and consequently promoted the deposition significantly. Such behavior might effectively contribute to the revitalized coronavirus disease 2019 (COVID-19) pandemic in addition to the more active virus itself in winter.

Analytical solutions of moisture‐chloride ion coupled transport in unsaturated concrete

AbstractStudies of chloride‐induced corrosion in reinforced concrete structures are performed based on the reliable predictions of chloride and moisture distributions in concrete. This paper adopted the Laplace Transformation and the inverse Laplace Transformation to obtain the analytical solutions of the moisture‐chloride two‐way coupled transport processes. Additionally, the model has involved with realistic material parameters to predict the internal distributions of relative humidity and free chloride ions in concrete samples. To illustrate the accuracy of the present model, the calculations were compared with the available experimental results, and good agreements were obtained. It indicates that the present analytical model can successfully characterize the two‐way coupling effects between chloride transport and moisture diffusion in concrete; and the model can provide the distribution profiles of both chloride and relative humidity in concrete, which are useful for predicting the service life of reinforced concrete structures.

Proposal for improving of paddy rice drying process in dryers inclined pools

The operation of inclined type dryers for paddy rice is studied to improve their operation and efficiency, considering the variables of drying time, humidity distribution in the rice layer after drying and air velocities within the plenum. Simulating the distribution and velocities of the air flow before crossing the rice layer, the outlet ducts to the plenum are relocated and dampers are placed to distribute the flow evenly. On the other hand, it is proposed to replace the flat-type mesh with a zigzag-type mesh. To verify the proposed modifications, a scale model was built to determine the humidity and drying time variation inside the rice layer, obtaining more uniform moisture percentages within the rice layer and a decrease in drying time.&#x0D;

Estimation of ground-level particulate matter concentrations based on synergistic use of MODIS, MERRA-2 and AERONET AODs over a coastal site in the Eastern Mediterranean

Satellite-derived aerosol optical depth (AOD) products are widely used to estimate the spatial and temporal characteristics of ground-level particulate matters (PM). Satellite-based approaches in the operational use of PM estimation models have limitations such as missing values in satellite-based variables due to the impact of cloud cover, relative humidity, and aerosol vertical distribution. Therefore, the spatial-temporal resolution of the estimation models is forced to be improved by using AOD products having different temporal resolutions from different platforms. In this study, ground-based PM10 concentrations were aimed to be estimated using different gap-filled AOD datasets between 2008 and 2016 over a coastal site in the Eastern Mediterranean. For the estimation of PM10 concentrations, daily AOD data were mainly used from MODIS. Then, two different gap-filled MODIS AOD datasets with both AERONET and MERRA-2 AODs were also examined separately on both multi-annual and multi-seasonal basis since the number of MODIS AOD data was temporally limited in the region. A pattern recognition neural network (PRNN) model was used for the estimation of PM10 concentrations. AOD with several meteorological parameters from an on-site meteorological station and aerosol diagnostic products from MERRA-2 were used as inputs to the estimation model. The most significant variables for the model were identified in 23 independent variables using the multiple linear regression (MLR). The results indicated that the best estimation (R = 0.74) was obtained with the gap-filled AODMODIS+MERRA dataset for the period covering all years whereas the AODMODIS dataset alone showed the poorest performance (R = 0.62). However, the performance of the gap-filled datasets varied with the seasons. For example, the AODMODIS dataset alone showed the best estimation performance (R = 0.67) in the summer whereas the gap-filled AODMODIS+AERONET dataset had the best performance (R = 0.59) in the winter. Overall results suggest that for estimating ground-level PM concentrations, an approach of gap-filled AOD dataset usage for estimation models is useful especially in rainy seasons such as the winter and autumn where MODIS AOD retrievals are limited.