Noon Hours Research Articles

Long-term recurrent exposure to excessive heat in the east Mediterranean and climate resilience development – a case study in Israel

This work studies long-term trends of observed meteorological parameters and of exposure to excessive heat over 74 years in Israel (1950–2023). We report an increasing trend of recurring exposure of the Israeli population to excessive heat during most of the summer noon hours, with the heat index often above the physiologically no-risk threshold. Specifically, since the beginning of the millennium, a significant increase in summertime decadal means of ambient noontime temperature (Ta), absolute humidity (AH), and heat index (HI) is evident relative to the 1950’s (Ta: 0.06 °C/year, AH: 0.06 g/m3year, HI: 0.09 °C/year). The experienced increase summertime thermal discomfort by the Israeli population results from the significant and synergistic increase in co-exposure to ambient temperature and humidity. Indeed, long-term satellite data (Landsat 1984–2021) of the east Mediterranean Sea Surface Temperature (SST) reveal a significant change (SST: 0.05 °C/year), which elucidates the corresponding increase in the absolute humidity. Leishmaniasis is a climate-related vector-borne infectious disease. However, the 1956–2017 leishmaniasis incidence rates in Israel do not correlate with the significant increase in the ambient temperature and heat index, representing development of climate resilience in terms of administrated prevention measures (namely, systematic adaptation) to this climate-related disease.

Coherence of Compressional Pc3‐4 Pulsation Driven by Upstream Waves in Topside Ionosphere Observed by the Swarm Constellation

AbstractIn this study, we presented a detailed analysis of ultralow frequency compressional waves with frequencies ranging from 16 to 100 mHz by using magnetic measurements of Swarm A and B, when the two spacecraft were flying in a counter‐rotating configuration. These waves are assumed to be driven by processes in the fore‐shock region and subsequently termed as upstream waves (UWs). An automatic detection algorithm for identifying UW events has been developed and applied to the Swarm magnetic measurements. Different to previous studies we take advantage of the counter‐rotating Swarm constellation to investigate the large‐scale homogeneous wavefield. Only B‐field oscillations from both Swarm A and B satellites satisfy the following criteria are accepted for UWs analysis: (a) highly correlated with normalized correlation coefficient (Cc) larger than 0.9; (b) shifted by less than 3 s between observations; (c) separated up to 90° in latitude and/or longitude. By this procedure we have identified from the years 2018–2023 in total 577 orbits containing UWs in the magnetic recordings of both spacecraft. In the first step, we checked phase shifts between UW detections at large latitudinal separation. The two counter‐rotating spacecraft allowed to make use of the Doppler effect to check the possible propagation of UWs at ionospheric altitude. Although individual events show signs of north‐south wave propagation, on average no systematic motion could be found. Similarly, possible wave motions toward or away from noon hours have been checked. By analyzing the simultaneous observations at larger longitudinal separation, also hardly any phase differences are identified in the east‐west direction. Further by evaluating the statistical results, a mean tiny local time effect seems to emerge, indicating on average an earlier arrival of the waves in the morning and later in the evening hours.

Toward sustainable energy resource: Integrated concentrated photovoltaic and membrane distillation systems for fresh water and electricity production

This study introduces and evaluates a novel Concentrated Photovoltaic (CPV)-assisted Direct Contact Membrane Distillation (DCMD) system, examining its efficiency and energy output under varying operational conditions. A Computational Fluid Dynamics (CFD) model, validated with experimental data, assesses the system's performance at different concentration ratios ranging from 1x to 10x and 25x to 100x, flow patterns (counterflow and parallel flow) at different Reynolds numbers (30–1200). This study investigates the seasonal performance of the CPV-DCMD system, providing valuable insights into its reliability and sustainability throughout the year. Results show increased mass flux and electric power with higher concentration ratios, especially at lower Reynolds numbers. In the counter-flow arrangement, the mass flux increases notably under specific conditions, while seasonal analysis reveals peak flux during summer and autumn afternoons. Electric power output follows a consistent trend across seasons, with high output observed during noon hours. The study demonstrates the system's energy efficiency, with notable energy gain compared to consumption across diverse operational conditions. Overall, the findings provide insights into optimizing the performance of CPV-assisted DCMD systems for sustainable energy generation and water desalination applications.

Radiative cooling performance analysis of cooling wood with three delignification processes for building applications

The delignification process is essential in the preparation of radiative cooling wood, and optimizing the delignification process is crucial for achieving a balance in the optical, mechanical, and thermal insulation characteristics of the delignify wood. Using the orthogonal experimental method, the study explored the influence of different delignification processes (such as chlorite, sulfite, and hydrogen peroxide methods), treatment duration, temperature, and other factors on wood weight loss rate, infrared spectroscopy, tensile and flexural strength, thermal conductivity, reflectance, and emissivity in order to obtain the best delignification process parameters for preparing radiative cooling wood with the optimal overall performance. The experimental results showed that delignification treatment followed by hot pressing improved the mechanical properties of the wood. As the delignification temperature and duration increased, the wood weight loss rate also increased, the mechanical properties declined, and the thermal insulating properties improved. The comprehensive comparison revealed that using the hydrogen peroxide method with treatment temperature at 80 °C and lasting 4 h can achieve the best overall performance for radiative cooling wood. Compared with Balsa wood, the tensile strength increased by 4.2 times and the flexural strength by 2.3 times, while the thermal conductivity reached 0.08 W/mK. In outdoor experiments, this radiative cooling wood can attain a good cooling effect throughout the day. During the noon hours, its surface temperature was lower than that of cement and the ambient temperature by 11.4℃ and 4.4℃ respectively, and the net radiative cooling power was up to 46 W/m2. The results show broad prospects for its application in building insulation and energy saving.

Variability of Index of Coalescence Activity (ICA) over a rain-shadow region during monsoon and its role in cloud seeding programs in India

The Index of Coalescence Activity (ICA) is an indicator of the microphysical state of the cloud. ICA is related to cloud base temperature and buoyancy of cloud at 500 hPa level. It is a useful parameter for making a decision on the type of seeding to be carried out. During Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) over the Indian region, aircraft operations for in situ measurements of aerosols and clouds were conducted from the base station Hyderabad to cover parts of north peninsular India falling under the rain-shadow region. Special Radiosonde flights were conducted in the afternoon hours prior to aircraft operations from the locations Hyderabad and Mahabubnagar in addition to regular India Meteorological Department (IMD) Radiosonde flights at 00 UTC from Hyderabad. The parameters like cloud base height and buoyancy at 500 hPa level obtained from Radiosonde flights have been used to estimate ICA values during the period of the experiment (June to October 2009–2011). The variability of ICA has been studied using morning and afternoon sounding profiles over the rain-shadow region. Morning hours showed highly negative ICA values, as compared to noon hours. During noon time, positive ICA values are observed before monsoon onset (in 2009, monsoon onset was 21st June over the study area) and on few occasions during post-monsoon (October). Positive ICA values represent that collision-coalescence (CC) process is not fully developed and hence, hygroscopic seeding is the proper decision. While, negative ICA values indicate active CC process, suggesting glaciogenic seeding. The soundings conducted just before the cloud seeding operations provide information about the actual thermodynamic and microphysical state of the cloud. Hence, ICA information is useful for providing guidelines to the operational cloud seeding programs.

Thermodynamic analysis of a solar-driven vapor compression refrigeration system using R1234ze for cooling applications in Ghardaïa region (Southern Algeria)

This study presents a thermodynamic analysis of a solar-driven vapor compression refrigera-tion (VCR) system designed for use in the region of Ghardaïa (Southern Algeria) which is lo-cated in a desert with a semi-arid climate where the demand for cooling is high, and the solar radiation is abundant. Two working fluids are tested and compared, the HFC high GWP going to phased out, R134a and the low GWP, HFO refrigerant recently introduced R1234ze. The performance of the solar VCR system was evaluated using a numerical model developed in MATLAB software, based on thermodynamic properties of R1234ze and R134a refrigerants. The results showed that coefficient of performance (COP) and thermodynamic efficiency of the solar VCR system increased with decreasing ambient temperature due to the increase in the compressor power consumption. The COP during the 21st day of July month is obtained in the range of 4.37–5.77 for R1234ze refrigerant which are close and more than 90% of the maximum COP value, while it is in the range of 2.56–3.17 for R134a fluid. The lowest COP values are found around noon hours during 12:00 AM and 15:00 PM. In addition, the greatest amount of the PV power production for R134a and R1234ze refrigerants occurs in the middle of the day (12:00 PM) as 2.8 and 1.6 kWh, respectively.

Null mutants of a tomato Rho of plants exhibit enhanced water use efficiency without a penalty to yield.

Improving water use efficiency in crops is a significant challenge as it involves balancing water transpiration and CO2 uptake through stomatal pores. This study investigates the role of SlROP9, a tomato Rho of Plants protein, in guard cells and its impact on plant transpiration. The results reveal that SlROP9 null mutants exhibit reduced stomatal conductance while photosynthetic CO2 assimilation remains largely unaffected. Notably, there is a notable decrease in whole-plant transpiration in the rop9 mutants compared to the wild type, especially during noon hours when the water pressure deficit is high. The elevated stomatal closure observed in rop9 mutants is linked to an increase in reactive oxygen species formation. This is very likely dependent on the respiratory burst oxidase homolog (RBOH) NADPH oxidase and is not influenced by abscisic acid (ABA). Consistently, activated ROP9 can interact with RBOHB in both yeast and plants. In diverse tomato accessions, drought stress represses ROP9 expression, and in Arabidopsis stomatal guard cells, ABA suppresses ROP signaling. Therefore, the phenotype of the rop9 mutants may arise from a disruption in ROP9-regulated RBOH activity. Remarkably, large-scale field experiments demonstrate that the rop9 mutants display improved water use efficiency without compromising fruit yield. These findings provide insights into the role of ROPs in guard cells and their potential as targets for enhancing water use efficiency in crops.

Simultaneous observations of atmospheric vertical potential gradient from coastal Antarctic stations Bharati and Maitri

Simultaneous observations of the atmospheric electric potential gradient (PG) at Bharati and Maitri stations were studied from 2014 to 2016. A new regional diurnal pattern of fair-weather PG for the coastal Antarctic region, perhaps the ubiquitous characteristics of the PG for the coastal Antarctic region, has been identified. This pattern has a significant broad minimum around noon hours. It is around this time the wind speed is also maximum. The PG data of past years of Syowa, Vostok, and Carnegie Cruise were also used in this study. The surface wind distorts the fair-weather diurnal pattern of PG over Bharati more intensely than at Maitri. The katabatic wind effect on the PG at Bharati appears to be more intense than at Maitri. The topography and katabatic winds associated with the Lambert glacier could be the reason. The observation of Bipolar Air Ion Concentration (BAIC) suggests that the wind speed significantly affects the concentration by accumulation and dispersion. The concentration is maximum when the wind speed is minimum. As the air ion concentration controls the conductivity, the PG is expected to be minimum during these hours to produce an anomalous diurnal pattern in the PG at Bharati. Data quality is improved by measuring the PG with a field monitor at the surface level instead of at an elevated position. This study provides new hope in pursuing globally representative data of the PG for further investigations on the global thunderstorm activity and the solar-terrestrial weather relationship.

Sub-ambient daytime cooling effects and cooling energy efficiency of a passive sub-ambient daytime radiative cooling coating applied to telecommunication base stations— Part 1: Distributed base stations and long-lasting self-cleaning properties

To overcome the issue of overheating and conserve cooling energy consumption, a superamphiphobic passive sub-ambient daytime radiative cooling (PSDRC) coating was extensively applied to distributed telecommunication base stations. The top surfaces of the battery and equipment cabinets coated with the PSDRC coating indicated prominent sub-ambient cooling effects regardless of the climate; this resulted in substantially lower surface temperatures compared with their counterparts. The applications of the PSDRC coating reduced the chamber interior temperature of an equipment cabinet by 10.4 °C during noon hours and by 6.0 °C before sunrise. The PSDRC-coated base stations could properly operate without air conditioners by replacing the closed door with a modified one containing an external exhaust system. The drastic decrease in the chamber interior temperature of the PSDRC base stations allowed them to conserve a considerable amount of cooling energy; this, resulted in cooling energy efficiencies between 31.7% and 64.9%. After more than one year, the surfaces of the PSDRC base station near busy city transit roads were still spotless and super non-wettable; this demonstrated the significance of the superamphiphobic self-cleaning topcoat and provided the top surfaces of the base stations in various regions with identical sub-ambient cooling effects on the initial state.

Expanded glass sphere/lauryl alcohol composite in gypsum: Physico-mechanical properties, energy storage performance and environmental impact assessment

In recent years, thermal energy storage systems, which are a promising solution to improve the thermal comfort of buildings and reduce energy demand, are a critical issue. This study aims to develop a new shape-stable gypsum composite using expanded glass sphere (EGS) and lauryl alcohol (LA) and analyses its thermal performances. For this purpose, EGS was impregnated with LA in different mass fractions (25 and 50%) by direct impregnation technique. DSC results exposed that melting temperature and melting enthalpy of shape-stable EGS/LA composite were 20.97 °C and 83.1 J/g, respectively. FTIR investigations confirmed the existence of well chemical compatibility between EGS and LA. TGA analysis revealed that the operating temperature of EGS/LA was considerably lower than its thermal degradation temperature. While incorporation of EGS and EGS/LA composite increases water absorption and porosity; caused a decrease in compressive strength, dry unit weight and ultrasound pulse velocity properties. EGS/Gypsum composite with LA (50%) provided a warmer room temperature for more than 12 h between midnight and solar noon hours. It achieved about 2 ℃ warmer room during these hours. After solar noon hours, proposed composite attained about 3.6 ℃ cooler room center temperatures. It provided cooler indoor temperatures for more than 5 h. A warmer indoor temperature was observed for EGS/Gypsum composite with LA (50%) after 18:00 until midnight to be 2 ℃. It can provide a carbon emission saving of around 3–23.2 kg-CO2/kWh, depending on fuel type for a wall cover made of EGS/Gypsum with LA.

Morphobiological and Qualitative Features of Chickpeas in Rainfed Farming Conditions of Mountainous Shirvan

The article presents 63 chickpea varieties introduced from 5 nurseries of ICARDA, where the yield, structural elements of production, grain quality and surface temperature in rainfed farming conditions were evaluated and compared with the Sultan variety taken as a standard. The research was carried out at the Gobustan Regional Experimental Station of the Research Institute of Agriculture under rainfed farming conditions of Mountainous Shirvan in 2017-2018. The difference between the surface temperature and the air temperature varied in different varieties and depended on the biological features of the variety. Surface temperature in chickpea varieties from nurseries varied in the range of 20.1-23.1°C in the noon hours, and in the noon — in the range of 21.7-23.7°C. The difference between the temperature of the vegetation cover and the air temperature in the daytime decreased and varied in the range of 8.1-10.7°C. This difference in comparison with the morning hours was 0.5-0.9°C. The temperature regime in the daytime of the studied varieties F.97.706, ILC 487, F.07-100, F.07-292, and F.09-210 was better regulated under drought conditions. In chickpea varieties selected for economically important traits, taken from various international nurseries, yield indicators were 265-385 g/m2. The average yield values of these variety accessions were above the standard and this difference was 50 g/m. Here, the maximum yields were obtained in accessions F.09-304 (380 g/m2) and F.09-294 (385 g/m2). The yield of protein per hectare varied in the range of 7.38-10.4 cwt/ha, the highest rates were obtained in varieties with a total growing season of 207 days — F.09-304 (9.88 cwt/ha) from the CIEN nursery — W, F.07-292 (9.01 cwt/ha) from the CIEN-DT nursery and F.09-294 (10.4 cwt/ha) from the CIABN nursery.

Satellite-based electron density background definition at mid-latitudes and comparison with IRI-2016 model under different solar conditions

A new method to define a background for the ionospheric electron density (Ne) is proposed, making use of mid-latitude measurements under different solar conditions from the Langmuir Probes onboard CHAMP and three identical Swarm satellites. In particular, CHAMP measurements during the years 2004 and 2009, and Swarm observations during 2016 and 2017 have been considered in the 15°-wide latitudinal belt from 35°N to 50°N, and from 0° to 360° in longitude. CHAMP/Swarm in-situ Ne measurements have been then used to check and compare this new defined background with the one computed directly from IRI-2016 Ne output at satellite altitude. The distributions of the relative deviations between the two backgrounds, and of positive and negative anomalies (i.e., Ne variations from each background greater than 30%) with respect to the geomagnetic activity levels have been evaluated under each investigated condition, namely year/satellite, season, night-time or noon hours. Results of this comparison highlight a general overestimation of Ne from IRI during noon hours, while a better agreement between the two backgrounds is found during night-time. However, an underestimation of IRI with respect to Swarm-derived background is found for 2017 data. Finally, the analysis of 2004 plasma data suggests that the IRI-2016 model can be used as a background during periods characterized by high levels of geomagnetic activity. Due to the difficulties to construct a background for satellite data, the proposed method can be considered an useful tool for analyses of electron density variations at the heights of the satellites in Low Earth Orbits (LEO).

Do urban tree hydraulics limit their transpirational cooling? A comparison between temperate and hot arid climates

Evaporative cooling due to transpiration of urban trees in two contrasting climates is the subject of this study. Transpiration was studied experimentally on local tree species at ‘tree lab’ sites in Munich, Germany (temperate climate) and in Beer Sheva, Israel (hot arid climate), within various settings (park, street, square) with natural and sealed surface conditions. The comparison was based on linear relationship of midday canopy resistance to atmospheric vapor pressure deficit (VPD), where the slope is proportional to tree hydraulic conductance and midday stem water potential. Sap flux densities in all trees were similar but crown projected area (CPA) was larger in Beer Sheva, resulting in higher hydraulic resistance that limits transpirational cooling (regression slopes of 0.25–0.44 in Beer Sheva vs. 0.10–0.18 in Munich). The contribution of the transpirational cooling, studied as the proportion of latent heat to total available energy was about 40% less significant at noon hours in summer in Beer Sheva than in Munich. Results suggested that shading should be the main consideration in planting local trees in hot dry climates. The linear relationship of midday canopy resistance to VPD is proposed as an operative tool for comparing evaporative cooling between local trees in different climatic regions.

ASSESSMENT OF BRAIN BIOELECTRICAL ACTIVITY IN CLINICALLY HEALTHY FLIGHT PERSONNEL AND FLIGHT TRAINING CANDIDATES FOLLOWING COVID-19 INFECTION

Introduction: Electroneurophysiological tests, together with tests to evaluate structures of the central nervous system (CNS), are in neurological diagnostics among the basic additional specialized examinations for diagnostic, therapeutic and certification purposes. The electroencephalographic (EEG) test is one of the methods of elelectroneurophysiological evaluation of the CNS. EEG is a non-invasive objective test of the bioelectrical activity of the brain. Objective: To investigate whether the course of COVID-19 with clinical mild/moderate respiratory tract involvement, in non-hospitalized patients, may affect brain bioelectrical activity. Methods: Eighty-five subjects were selected for evaluation of EEG recordings from clinically initially healthy flight personnel and flight training candidates. Of all the male and female subjects, between 04 January 2021 to 31 January 2022, as part of periodic and qualifying certification examinations at the Military Institute of Aviation Medicine, for the purposes of the Regional Military Aviation and Medical Commission. The selected group consisted of individuals aged 14-60 (average age: 27 years and 6 months), which included 14 women (average age: 24 years and 2 months) and 71 men (average age 29 years and 3.5 months). The subjects were ill with COVID-19 (non-hospitalized) for approximately 3-4 weeks, during the period; June 2020 – December 2021. Routinely made recordings of bioelectrical brain activity with the Grass Technologies EEG TWin 4.5.3 system were visually evaluated. EEG examinations were performed in the supine position, in the before noon hours, in a darkened and acoustically isolated laboratory. Before the study, each person declared min. 6-8 hours of sleep and eating a meal (breakfast). Except for the flight training candidates and one person from flight personnel, all other subjects declared having received one and 29 subjects two SARS-CoV-2 vaccinations, prior to contracting COVID-19. Some subjects had one further revaccination after recovery from the disease. EEG examinations were performed between one and fourteen months after recovery from COVID-19. The mean time between recovery and EEG examination was 6.5 (6.47) months. Results: EEG recordings within normal limits (normal) were found in 79 subjects, while six subjects (7.05%) had abnormal brain bioelectrical activity recordings. Discussion and Conclusion: Infection with SARS-CoV-2 with clinical mild/moderate respiratory tract involvement by initially healthy individuals may adversely affect spontaneous brain bioelectrical activity in some individuals.

Long-term cooling effects and cooling energy conservation of a subambient daytime radiative cooling coating relative to a cool-white coating over distributed telecommunication base stations

A superamphiphobic self-cleaning passive subambient daytime radiative cooling (SSC-PSDRC) coating with ultrahigh solar reflectance and emissivity was applied to distributed telecommunication base stations (d-TBSs) in various climatic regions. The SSC-PSDRC surface showed remarkable PSDRC effect both in the absence and presence of heat-producing electronic equipment. After exposure to severe outdoor conditions for more than one year, the top surface of the spotless d-TBS still exhibited a strong subambient cooling effect under peak sunlight conditions, owing to the presence of the SSC topcoat. Regardless of the identical appearance, the top-surface temperature difference during the noon hours between the cool-white- and SSC-PSDRC-coated d-TBSs was as high as 24.2 °C, resulting in a chamber interior temperature decrease of the SSC-SDRC-coated d-TBSs. Consequently, the measured cooling energy consumptions of the SSC-PSDRC-coated d-TBS in Kashgar for one year and that in Panzhihua for 290 d were 1044.9 and 2083.3 kWh, respectively, both of which were underestimated. In the long term, the annual cooling energy conservations estimated using different methods correlated well with the measured value in Kashgar. After five cycles of dirt- and 2200 h of artificial accelerated weathering-resistance tests, the solar reflectance of the SSC-PSDRC coating decreased by only 0.015 and 0.023, respectively. These excellent performances were attributed to the unique molecular structure of the superamphiphobic topcoat which contained networks of –Si–O–.

Diurnal and seasonal rhythm of the melon ladybird - Epilachna chreysomelina (Coleoptera, Coccinellidae) activity in the conditions of the Kashkadarya region of Uzbekistan

The paper describes that the first signs of beetle movement after night rest in the month of May occur at 8 am at an air temperature of about 200C. Increasing the temperature to 22-290C tends to increase their mobility. By 11 a.m., when the air temperature reached 340C, almost all the beetles went into the shade, into the lower part of the plants, where they remained immobile until almost 4 p.m. After 17 h. the air temperature dropped to 330С, by 20:00 to 200С. By this time, only a small part of the beetles remained active. In summer, the motor activity of beetles intensifies at 8-10 am, when the air temperature rises to 340C. From 11 a.m. to 6 p.m. at a temperature of 34-420C, humidity 34-40%, the beetles were placed in the shade and were inactive. In autumn, after night cooling, the air temperature increased later and the movement of beetles began at 11 am At noon hours (between 12-4 pm) at an air temperature of 20-250C. and humidity 55-60%, beetle activity was maximum. In summer, beetles actively feed in the morning (from 8-9 a.m.) and evening (from 19 to 22 p.m.) hours, when the air temperature was 26-330C. In the middle of the day (13-16 hours) and at night (3-5 hours), their feeding activity is somewhat reduced. The intensity of beetle feeding in the autumn months increases from 9 a.m. and reaches a maximum by 11-13 a.m., and after 5 p.m. it begins to decrease and almost stops at 9 p.m. in the evening.

Magnetic local time (MLT) dependence of auroral peak emission height and morphology

Abstract. We investigate the bulk behaviour of auroral structures and peak emission height as a function of magnetic local time (MLT). These data are collected from the Fennoscandian Lapland and Svalbard latitudes from seven identical auroral all-sky cameras (ASC) over about one solar cycle. The analysis focusses on green auroral emission, which is where the morphology is most clearly visible and the number of images is the highest. The typical peak emission height of the green and blue aurora varies from 110 km on the nightside to about 118 km in the morning MLT over the Lapland region. It stays systematically higher (at 118–120 km) at high latitudes (Svalbard) during the nighttime and reaches 140 km at around magnetic noon. During high solar wind speed (above 500 km s−1), nightside emission heights appear about 5 km lower than during slow solar wind speed (below 400 km s−1). The sign of the interplanetary magnetic field (IMF) has nearly no effect on the emission heights in the night sector, but the northward IMF causes lower emission heights at dawn over Lapland and during the noon hours over Svalbard. While the former is interpreted as a change in the particle population within the field-of-view (FoV), the latter is rather due to the movement of the cusp location due to the IMF orientation. The morning sector heights also show a pronounced difference when previously detected pulsating aurora (PsA) events have been excluded/included in the dataset, suggesting that this type of aurora is a dominant phenomenon in the morning and an important dissipation mechanism. An increase of complex auroral structures in the midnight hours agrees with the average substorm occurrence. This increase is amplified during stronger solar wind driving and during higher geomagnetic activity (as measured by auroral electrojet index, AL). During high solar wind speed, the high latitude auroral evolution shows particularly complex morphology, which is not limited to the nightside but rather only excludes the magnetic noon hours. An increase in the geomagnetic activity further enhances the structural complexity of the aurora in the morning sector.

Selenographic and Local Time Dependence of Lunar Exospheric Sodium as Observed by LADEE

Even though sodium (Na) has been known to be a constituent of the lunar exosphere for the past thirty years, limitations introduced by Earth-based observations make it difficult to determine how its distribution varies with local time. We used observations from the Ultraviolet and Visible Spectrometer instrument on board the NASA Lunar Atmosphere and Dust Environment Explorer mission to search for evidence of near-instantaneous dayside variation of exospheric Na across one lunation (2014 February–March). Through comparison with model simulations, the data appear to be consistent with persistent southern enhancements of Na, while no evidence of systematic depletion of the Na exosphere reservoir within two hours of local noon was obtained. The results indicate an enhancement of the gas density over Mare regions and the lunar nearside; though this finding could mean that the weak Na emission is lost in the scattering continuum over brighter soils. Day-to-day variability is observed and may reflect a changing solar wind and meteoroid environment combined with inhomogeneities in the gas–surface interaction parameters and Na distribution on the lunar surface. We found that, due to the limited viewing geometry and sensitivity of the instrument to scattering from the bright lunar surface, it is difficult to uniquely separate the latitudinal and local time variations of Na.

The Situation of Hazardous Materials Accidents during Road Transportation in China from 2013 to 2019.

The safety situation of hazardous materials (hazmat) accidents during road transportation in China is severe and very serious accidents occurred frequently. Such accidents not only have a huge impact on the environment but also have serious consequences for people and the economy, such as fires and explosions. Therefore, it is necessary to understand the characteristics and laws of road transport accidents of hazmat systematically. This paper investigated 2777 hazmat transportation accidents in China from 2013 to 2019 to identify the characteristics, consequences, and causes of the accident. The results show that August (10.05%) and December (9.76%) are the peak periods of hazmat transportation accidents, while most hazmat transportation accidents occurred in the early morning (6:00–9:00 a.m.) and at noon (9:00 a.m.–12:00 p.m.) hours. For the geographical location, the accidents mainly occurred in the east China (34.35%) and the northwest China areas (14.87%). The main types of hazmat transportation accidents were rollover (35.36%), rear-end (22.58%), and collision (14.87%), where the probability of a major leak was high. The most common hazmat transportation accidents involve gas (17.79%), flammable liquid (56.07%), and corrosive substance (12.28%). The most common consequences of the hazmat transportation accidents were leakage (80.34%), followed by fire release (8.32%) and explosion release (2.34%). Human factor (26.74%) is the main cause of hazmat transportation accidents. These findings could help hazmat transportation managers and planners develop appropriate measures for improving hazmat transportation safety.

Combining NDVI, PRI and the quantum yield of solar-induced fluorescence improves estimations of carbon fluxes in deciduous and evergreen forests

We used automated spectroradiometers to continuously monitor changes in the optical parameters of phenological and photosynthetic traits in beech and spruce forests. We examined seasonal variations in the normalized difference vegetation index (NDVI), photochemical reflectance index (PRI), and solar-induced fluorescence in the oxygen A band (SIFA) that was estimated using a 3-FLD discrimination method from radiance data. The optical parameters tracked the activation and cessation of photosynthesis in spring and autumn. Data at photon fluxes >1200 μmol m−2 s−1 during extended noon hours were used to link the seasonal PRI and SIFA variations to the dynamics of photosynthesis. Seasonal PRI was significantly correlated with photosynthetic light-use efficiency (LUE) with R2 values of 0.66 and 0.48 for the measurements in beech and spruce forests, respectively. SIFA emissions were significantly correlated with the gross primary production (GPP) of the evergreen spruce forest (R2 = 0.47), but R2 was only 0.13 when measured in the beech forest. The correlations between the optical parameters and GPP or LUE, however, tended to be lower when using a dataset with constant NDVI. Introducing an equation combining NDVI, PRI, and the quantum yield of SIFA emission increased R2 for LUE estimation to 0.77 in the spruce forest and 0.63 in the beech forest. GPP was estimated from the parametric equation with improved accuracy reaching R2 = 0.53 and RMSE = 5.95 μmol CO2 m−2 s−1 in spruce forest and R2 = 0.58 and RMSE = 5.23 μmol CO2 m−2 s−1 in beech forest. Parametric equations were more efficient in estimating photosynthesis in datasets that consisted of an entire season's data. By combining NDVI, PRI and the quantum yield of SIFA, we could thus substantially improve estimations of carbon fluxes in diverse deciduous and evergreen canopies.