Water Vapor Pressure Research Articles

Effect of insolation heating of roof coverings on their performance reliability

Introduction. The article addresses the issues of ensuring the performance reliability of warm roofs in terms of condensation moisture accumulating in their structures, which causes leaks on the upper floors of buildings. Such problems are often revealed when buildings are inspected during repair and reconstruction works. Leaks in the ceilings of buildings with warm roofs were detected in dry, sunny weather with significant heating of the roof covering due to solar radiation.Aim. To examine the effect of the insolation heating of a roof covering on the formation of condensate in the warm roof of a building in summer, taking into account its design solution.Materials and methods. Materials are presented on inspection of buildings in the Moscow region for repair and reconstruction needs; they reveal the problem of leak formation in the warm roofs of buildings on dry, sunny summer days. The process of moisture transfer through the exterior covering was analyzed through analytical calculations using the roof design solution in the considered structure as an example.Results. The calculation of moisture transfer yielded vapor transmission resistance, conventional true and maximum partial pressures of water vapor, as well as temperatures at the layer boundaries in the studied structures. Changes in these parameters across the thickness of structures were revealed via a graphical method, which showed where the dew point indicating possible condensation in the covering is formed. For a comparative analysis, moisture transfer was calculated for a similar design in which mineral wool insulation was replaced by extruded polystyrene.Conclusions. 1. The calculations of moisture transfer in the examined covering designs confirmed the formation of condensate due to the insolation heating of the roof in summer. 2. The choice of a covering design solution in the design of buildings should be based on accurate heat and moisture calculations taking into account climatic conditions in the construction area, including for the summer season.

Evaluating the Polarimetric Radio Occultation Technique Using NEXRAD Weather Radars

Currently, it remains a challenge to effectively monitor areas experiencing intense precipitation and the associated atmospheric conditions on a global scale. This challenge arises due to the limitations on both active and passive remote sensing methods. Apart from the lack of observations in remote areas, the quality of some observations deteriorates when heavy precipitation is present, making it difficult to obtain highly accurate measurements of the thermodynamic parameters driving these weather events. However, there is a promising solution in the form of the Global Navigation Satellite System (GNSS) Polarimetric Radio Occultation (PRO) technique. This approach provides a way to assess the large-scale bulk-hydrometeor characteristics of regions with heavy precipitation and the meteorological conditions associated with them. PRO offers vertical profiles of atmospheric variables, including temperature, pressure, water vapor pressure, and information about hydrometeors, all in a single fine-vertical resolution observation. To continue validating the PRO technique, we make use of polarimetric weather data from Next Generation Weather Radars (NEXRAD), focusing on comparing specific differential phase shift (Kdp) structures to PRO observable differential phase shift (ΔΦ). We have seen that PAZ and NEXRAD exhibit a good agreement on the vertical structure of the observable ΔΦ and that their combination could be useful for enhancing our understanding of the microphysics underlying heavy precipitation events.

The Variation in Atmospheric Turbidity over a Tropical Site in Nigeria and Its Relation to Climate Drivers

Atmospheric turbidity exhibits substantial spatial–temporal variability due to factors such as aerosol emissions, seasonal changes, meteorology, and air mass transport. Investigating atmospheric turbidity is crucial for climatology, meteorology, and atmospheric pollution. This study investigates the variation in atmospheric turbidity over a tropical location in Nigeria, utilizing the Ångström exponent (α), the turbidity coefficient (β), the Linke turbidity factor (TL), the Ångström turbidity coefficient (βEST), the Unsworth–Monteith turbidity coefficient (KAUM), and the Schüepp turbidity coefficient (SCH). These parameters were estimated from a six-month uninterrupted aerosol optical depth dataset (January–June 2016) and a one-year dataset (January–December 2016) of solar radiation and meteorological data. An inverse correlation (R = −0.77) was obtained between α and β, which indicates different turbidity regimes based on particle size. TL and βEST exhibit pronounced seasonality, with higher turbidity during the dry season (TL = 9.62 and βEST = 0.60) compared to the rainy season (TL = 0.48 and βEST = 0.20) from May to October. Backward trajectories and wind patterns reveal that high-turbidity months align with north-easterly air flows from the Sahara Desert, transporting dust aerosols, while low-turbidity months coincide with humid maritime air masses originating from the Gulf of Guinea. Meteorological drivers like relative humidity and water vapor pressure are linked to turbidity levels, with an inverse exponential relationship observed between normalized turbidity coefficients and normalized water vapor pressure. This analysis provides insights into how air mass origin, wind patterns, and local climate factors impact atmospheric haze, particle characteristics, and solar attenuation variability in a tropical location across seasons. The findings can contribute to environmental studies and assist in modelling interactions between climate, weather, and atmospheric optical properties in the region.

Appropriate Water and Nitrogen Regulation Improves the Production of Wolfberry (Lycium barbarum L.)

Wolfberry (Lycium barbarum L.) production in arid and semi-arid areas is drastically affected by the low utilization rate of soil and water resources and the irrational application of water and nitrogen fertilizers. Thus, this study explored a high-yielding, high-quality, and efficient irrigation and nitrogen regulation model to promote the production efficiency of wolfberry and rational utilization of water and land resources in arid and semi-arid areas. We compared and analyzed the effects of different soil water treatments (the upper and lower limits of soil water were estimated as the percentage of soil water content to field water capacity (θf), with the following irrigation regimen: adequate irrigation (W0, 75–85% θf), mild water deficit (W1, 65–75% θf), moderate water deficit (W2, 55–65% θf), and severe water deficit (W3, 45–55% θf)) and nitrogen levels (no nitrogen (N0, 0 kg·ha−1), low nitrogen (N1, 150 kg·ha−1), moderate nitrogen (N2, 300 kg·ha−1), and high nitrogen (N3, 450 kg·ha−1)) on the growth, physiology, and production of wolfberry. The results showed that water regulation, nitrogen application level, and their interaction significantly affected plant height and stem diameter growth amount (p < 0.05). Additionally, the relative chlorophyll content of wolfberry leaves first increased and then decreased with increasing nitrogen levels and water deficit. The average net photosynthetic rate (Pn), stomatal conductance (gs), intercellular carbon dioxide concentration, and transpiration rate (Tr) reached the highest values in plants exposed to W0N2 (19.86 μmmol·m−2·s−1), W1N1 (182.65 mmol·m−2·s−1), W2N2 (218.86 μmol·mol−1), and W0N2 (6.44 mmol·m−2·s−1) treatments, respectively. Pn, gs, and Tr were highly correlated with photosynthetically active radiation and water vapor pressure difference (goodness-of-fit: 0.366–0.828). Furthermore, water regulation and nitrogen levels exhibited significant effects on the yield and water- (WUE), and nitrogen-use efficiency (NUE) (p < 0.01), and their interactions exhibited significant effects on the yield, WUE, and nitrogen partial productivity of wolfberry plants (p < 0.05). Moreover, the contents of total sugar, polysaccharides, fats, amino acids, and proteins were the highest in W1N2, W1N2, W1N2, W2N3, and W0N2 treatments, respectively, which were increased by 3.32–16.93%, 7.49–54.72%, 6.5–45.89%, 11.12–86.16%, and 7.15–71.67%, respectively. Under different water regulations (except for the W3 condition) and nitrogen level treatments, the net income and input–output ratio of wolfberry were in the order W1 > W0 > W2 > W3 and N2 > N3 > N1 > N0. The TOPSIS method also revealed that the yield, quality, WUE, NUE, and economic benefits of wolfberry improved under the W1N2 treatment, suggesting that WIN2 might be the most suitable irrigation and nitrogen regulation model for wolfberry production in regions with scarce land and water resources such as the Gansu Province and areas with similar climate.

Water Promotes Melting of a Metal-Organic Framework.

Water is one of the most reactive and abundant molecules on Earth, and it is thus crucial to understand its reactivity with various material families. One of the big unknown questions is how water in liquid and vapor forms impact the fast-emerging class of metal-organic frameworks (MOFs). Here, we discover that high-pressure water vapor drastically modifies the structure and hence the dynamic, thermodynamic, and mechanical properties of MOF glasses. In detail, we find that an archetypical MOF (ZIF-62) is extremely sensitive to heat treatments performed at 460 °C and water vapor pressures up to ∼110 bar. Both the melting and glass transition temperatures decrease remarkably (by >100 °C), and simultaneously, hardness and Young's modulus increase by up to 100% under very mild treatment conditions (<20 bar of hydrothermal pressure). Structural analyses suggest water to partially coordinate to Zn in the form of a hydroxide ion by replacing a bridging imidazolate-based linker. The work provides insight into the role of hot-compressed water in influencing the structure and properties of MOF glasses and opens a new route for systematically changing the thermodynamics and kinetics of MOF liquids and thus altering the thermal and mechanical properties of the resulting MOF glasses.

OPTIMIZATION OF THE CONDENSATE PUMPING SYSTEM AT THE GASOLINE SELECTIVE HYDROTREATING PLANT

The article discusses issues related to energy saving of the coolant – high, medium and low pressure water vapor in the condensate pumping system at the gasoline selective hydrotreating plant. The analysis of the current condensate pumping system is carried out and its main disadvantages are indicated. Retrofitting of the pumping system is proposed. A return line has been added and a pair of centrifugal pumps has been included in the technological scheme, a calculation has been made. The replacement of the equipment will optimize the steam consumption inside the gasoline selective hydrotreating plant and will reduce the cost of repair and maintenance of the unit, as well as electricity consumed for technological needs.

Changes in air Water Vapour Pressure, Relative Humidity and Carbon Dioxide Concentration in Summer on the City Outskirts

Changes in air Water Vapour Pressure, Relative Humidity and Carbon Dioxide Concentration in Summer on the City Outskirts

Demystifying Fogging in Lyophilized Products: Impact of Pharmaceutical Processing

A commonly encountered challenge with freeze-dried drug products is glass vial fogging. Fogging is characterized by a thin layer of product deposited upon the inner surface of the vial above the lyophilized cake. While considered to be a routine cosmetic defect in many instances, fogging around the shoulder and neck of the vial may potentially impact container closure integrity and reject rates during inspection. In this work, the influence of processing conditions i.e. vial pre-treatment, lyophilization cycle modifications and filling conditions on fogging was evaluated. A battery of analytical techniques was employed to investigate factors affecting glass vial fogging. A fogging score was used to quantify its severity in freeze-dried products. Additionally, a dye-based method was used to study solution upcreep (Marangoni flow) following product filling. Our lab-scale results indicate measurable improvement in fogging following the addition of an annealing step in the lyophilization cycle. Pre-freeze isothermal holding of the vials (at 5°C on the lyophilizer shelf) for an extended duration indicated a reduction in fogging whereas an increase in the freezing time exhibited no effect on fogging. Vial pre-treatment conditions were critical determinants of fogging for Type 1 vials whereas they had no impact on fogging in TopLyo® vials. The headspace relative humidity (RH) investigation also indicated sufficient increase in the water vapor pressure inside the vial to be conducive to the formulation of a hydration film - the precursor to Marangoni flow.

Modeling of multilayer water adsorption and condensation in slits of cement minerals by molecule simulation and adsorption isotherm

The interactions between water and multiscale pores affect significantly most of the physical and chemical properties of cementitious materials such as cement mortar, paste, and concrete. In this paper, molecular mechanism of multilayer water adsorption and condensation in micropores of typical cementitious minerals, the dicalcium silicate (C2S) and calcium silicate hydrate (C-S-H), were investigated by molecular simulations. Classical adsorption isotherm models were examined for their applicability to describe the adsorption law in molecular scales. Besides, the Kelvin equation was modified to satisfy the description of condensation at the microscale. Calculation results show that the most commonly used Brunauer-Emmett-Teller (BET) model can only describe the isotherms within a limited range of low water vapor pressures. In comparison, the modified Brunauer-Emmett-Teller-Pickett (BETP) model can describe the adsorption of water molecular on the surface of C2S and C-S-H more precisely, due to considering the adsorption layers as finite at saturation pressure and the reduced escape probability of the outermost layer of adsorbed water molecules. As for the condensation of water molecules in C2S and C-S-H slits, the traditional Kelvin equation is not applicable. Therefore, a refined Kelvin equation was proposed to describe the relationship between pore size and the pressure required for condensation accurately by considering the critical pore size, adsorption thickness, and decay rate of adsorption potential energy. Further analysis suggests that C2S releases more first-layer adsorption heat and thus shows stronger adsorption of water molecules compared to C-S-H.

Variation in canopy conductance of Cunninghamia lanceolata forest and its response to environmental factors after an extreme rainfall event

AbstractCanopy conductance (gc) is a crucial parameter in simulating evapotranspiration and modulating water exchange, but its variation mechanism has regional uncertainties and complex environmental co‐controls. In addition, the effect of extreme rainfall on gc cannot be ignored under the changing climate. Here, we investigated the variation and environmental controls on gc and the effect of extreme rainfall events in a Cunninghamia lanceolata forest across the subtropical area of Southern China. In July 2020, an extreme rainstorm hit the source area of the Xin'an River, with the cumulative rainfall on July 7 and 8 reaching 216.6 mm. The thermal diffusion probe method was used to measure the density of sap flow, and the environmental factors such as air temperature (Ta), net solar radiation (Rn) and soil water content (SWC) were monitored during the growing seasons of 2020 and 2021. Ultimately, gc obtained by the Penman‐Monteith equation was adopted since the result from the Köstner equation was overestimated. gc showed a unimodal curve on the diurnal scale, and this characteristic was more obvious after the extreme rainfall. Daily gc appeared a fluctuating pattern with a maximum in summer. gc was simultaneously affected by Ta, Rn, water vapour pressure difference (VPD), SWC, among which Ta was the most significant driving factor at both the diurnal and daily timescales. The regulation of Ta, VPD and SWC on gc had obvious thresholds, and the most definite response mode was VPD (2020: 1.25 kPa; 2021: 0.95 kPa). SWC and Ta were the dominant factors after the rainfall period, and the promotion effect of VPD on post‐rainy days turned to inhibition effect on typical sunny days. These findings will further reveal the water exchange mechanism between atmosphere and vegetation and impacts of environmental factors in subtropical coniferous forests, especially after the extreme rainfall events.

PROPERTIES OF SORBENTS FROM PINE BARK ACTIVATED BY MECHANOCHEMICAL METHODS

The influence of pine bark pre-activation conditions: 1) in a planetary mill AGO-2, 2) with water vapor under the conditions of explosive autohydrolysis (EAH), on the sorption activity of resulting sorbents with respect to methylene blue and gelatin was studied. It is shown that explosive autohydrolysis is a more efficient method to activate pine bark, and under certain conditions it leads to an increase in the sorption of methylene blue and gelatin at least by a factor of 1.8 and 3.8, respectively, compared with the sorbent from non-activated bark. The activating treatment of pine bark in a planetary mill makes it possible to increase the sorption of methylene blue and gelatin not more than by a factor of 1.3 and 1.2, respectively. A mathematical model is obtained that describes the effect of explosive autohydrolysis conditions (water vapour pressure and duration of pine bark treatment) on the sorption properties of the resulting sorbents. Optimal conditions providing the maximal sorption of methylene blue by the obtained sorbent are determined: temperature 155 °C; water vapour pressure 2.62 MPa; processing time 58.6 s. The sorption properties of the sorbent predicted by the mathematical model have been confirmed experimentally. Sorbents from pine bark, activated by explosive autohydrolysis, surpass the industrial enterosorbent Polifepan from hydrolytic lignin in their ability to absorb methylene blue and gelatin, which indicates the prospects for their use as enterosorbents in medicine and veterinary medicine. The results of the conducted research allow us to consider pine bark as an alternative raw material that can replace hydrolytic lignin in the production of effective enterosorbents.

Assessing intra-annual growth dynamics in climatically contrasting years, sites, and tree species using dendrometers and wood anatomical data

Detecting the intra-annual dynamics and courses of secondary tree growth enables the accurate identification of crucial steps in the forming of a new tree ring. Furthermore, comparing the high-resolution recordings of tree growth with environmental conditions allows assessment of the influence of weather on wood formation processes. This study investigates the intra-annual growth performance of conifer species and European beech at two high- and two low-elevation sites in Bavaria, southeast Germany. We measured stem circumference changes with electronic band dendrometers and cambial dynamics by collecting microcores at biweekly intervals. We analyzed growth variations between the consecutive years 2020 and 2021, which showed distinct climatic differences during the growing seasons. While warm and dry conditions prevailed in spring and summer in 2020, spring in 2021 was comparatively cold, and summer precipitation was high. Different tree growth patterns were observed in the contrasting years 2020 and 2021. Distinct growth reductions occurred in the drier year 2020 for most of the studied tree species, while trees showed wider tree rings in 2021 despite of low growth rates at the beginning of the growing season. Climate-growth correlations exposed the intraseasonal influence of climatic conditions, particularly available soil water, water vapor pressure deficit, and soil temperature, on short-term tree responses. Wood anatomical analysis and daily stem diameter variations proved to be valid monitoring methods to assess individual wood formation processes and to identify species-specific tree responses to the influence of climatic conditions. However, combining both methods represents the most reliable approach due to the mutual ability to compensate for each other’s deficiencies. While dendrometers provided a very accurate and high-resolution record of intra-annual tree growth, wood anatomical analyses were more reliable in determining the exact onset and cessation of wood formation. For this reason, combining both is recommended for assessing prospective tree growth performance in the context of climate change.

Complete Prevention of Bubbles in a PDMS-Based Digital PCR Chip with a Multifunction Cavity.

In a chamber-based digital PCR (dPCR) chip fabricated with polydimethylsiloxane (PDMS), bubble generation in the chambers at high temperatures is a critical issue. Here, we found that the main reason for bubble formation in PDMS chips is the too-high saturated vapor pressure of water at an elevated temperature. The bubbles should be completely prevented by reducing the initial pressure of the system to under 13.6 kPa to eliminate the effects of increased-pressure water vapor. Then, a cavity was designed and fabricated above the PCR reaction layer, and Parylene C was used as a shell covering the chip. The cavity was used for the negative generator in sample loading, PDMS degassing, PCR solution degassing in the digitization process and water storage in the thermal reaction process. The analysis was confirmed and finally achieved a desirable bubble-free, fast-digitization, valve-free and no-tubing connection dPCR.

Distinct Site Motifs Activate O2 and H2 on Supported Au Nanoparticles in Liquid Water.

Au nanoparticles catalyze the activation and conversion of small molecules with rates and kinetic barriers that depend on the dimensions of the nanoparticle, composition of the support, and presence of catalytically culpable water molecules that solvate these interfaces. Here, molecular interpretations of steady-state rate measurements, kinetic isotope effects, and structural characterizations reveal how the interface of Au nanoparticles, liquid water, and metal oxide supports mediate the kinetically relevant activation of H2 and sequential reduction of O2-derived intermediates during the formation of H2O2 and H2O. Rates of H2 consumption are 10-100 fold greater on Au nanoparticles supported on metal oxides (e.g., titania) compared to more inert and hydrophobic materials (carbon, boron nitride). Similarly, Au nanoparticles on reducible and Lewis acidic supports (e.g., lanthana) bind dioxygen intermediates more strongly and present lower barriers (<22 kJ mol-1) for O-O bond dissociation than inert interfaces formed with silica (>70 kJ mol-1). Selectivities for H2O2 formation increase significantly as the diameters of the Au nanoparticles increase because differences in nanoparticle size change the relative fractions of exposed sites that exist at Au-support interfaces. In contrast, site-normalized rates and barriers for H2 activation depend weakly on the size of Au nanoparticles and the associated differences in active site motifs. These findings suggest that H2O aids the activation of H2 at sites present across all surface Au atoms when nanoparticles are solvated by water. However, molecular O2 preferentially binds and dissociates at Au-support interfaces, leading to greater structure sensitivity for barriers of O-O dissociation across different support identities and sizes of Au nanoparticles. These insights differ from prior knowledge from studies of gas-phase reactions of H2 and O2 upon Au nanoparticle catalysts within dilute vapor pressures of water (10-4 to 0.1 kPa H2O), in which catalysis occurs at the perimeter of the Au-support interface. In contrast, contacting Au catalysts with liquid water (55.5 M H2O) expands catalysis to all surface Au atoms and enables appreciable H2O2 formation.

Ecosystem CO2 Exchange and Its Environmental Regulation of a Restored Wetland in the Liaohe River Estuary

Coastal wetlands are important carbon sinks， and they contribute to reducing the effects of global warming. This study used the eddy covariance method to detect the CO2 flux in the restoration wetland of the Liaohe River estuary in 2021 and investigate the characteristics of ecosystem CO2 exchange and its environmental control factors. The aim was to assess the carbon source/sink capacity of salt marshes in the restored area and to provide data support and theoretical basis for evaluating the effectiveness of ecological restoration projects. The study revealed "U" curves in spring and autumn， "V" curves in summer， and horizontal lines in winter for the average daily variation curve of net ecosystem CO2 exchange （NEE） in the restored area. Its carbon sink efficiencies were -40.06， -63.62， 2.33， and 34.43 g·m-2 in the spring， summer， autumn， and winter， respectively. In the restored area， the daily cumulative variation in NEE was "V" shaped， and the monthly cumulative changes in NEE， ecosystem respiration （Reco）， and gross primary productivity （GPP） were obviously different. Photosynthetically active radiation （PAR） was an important regulation factor of daytime NEE in the restored area in 2021， and they displayed a rectangular hyperbolic relationship. PAR could explain 53% of the variation in the daytime NEE. Air temperature （Ta） was the main control factor of Reco，night， and there was an exponential relationship between them. When Ta &lt; 5.5 ℃， the temperature sensitivity of ecosystem respiration （Q10） was 2.19， and Ta could explain 42% of the variation in the Reco，night； when Ta ≥ 5.5 ℃， the Q10 was 1.81， and Ta could explain 51% of the variation in the Reco，night. Additionally， there were significant linear negative correlations between NEE and both soil water content （SWC） and vapor pressure deficit （VPD）， whereas NEE was not significantly correlated with soil temperature （Ts） or relative humidity （RH）. In 2021， the restored wetland in the Liaohe River estuary acted as a CO2 sink， and the total net carbon sequestration was -66.89 g·m-2. The restored salt plays a role as an important carbon sink and has long-term carbon sequestration potential.

Stomatal conductance reduction tradeoffs in maize leaves: A theoretical study.

As the leading global grain crop, maize significantly impacts agricultural water usage. Presently, photosynthesis ( ) in leaves of modern maize crops is saturated with , implying that reducing stomatal conductance ( ) would not affect but reduce transpiration ( ), thereby increasing water use efficiency (WUE). While reduction benefits upper canopy leaves under optimal conditions, the tradeoffs in low light and nitrogen-deficient leaves under nonoptimal microenvironments remain unexplored. Moreover, reduction increases leaf temperature ( ) and water vapor pressure deficit, partially counteracting transpiratory water savings. Therefore, the overall impact of reduction on water savings remains unclear. Here, we use a process-based leaf model to investigate the benefits of reduced in maize leaves under different microenvironments. Our findings show that increases in due to reduction can diminish WUE gains by up to 20%. However, reduction still results in beneficial WUE tradeoffs, where a 29% decrease in in upper canopy leaves results in a 28% WUE gain without loss in . Lower canopy leaves exhibit superior tradeoffs in reduction with 178% gains in WUE without loss in . Our simulations show that these WUE benefits are resilient to climate change.

Observational relationships between ammonia, carbon dioxide and water vapor under a wide range of meteorological and turbulent conditions: RITA-2021 campaign

Abstract. We present a comprehensive observational approach that aims to establish relationships between the surface–atmosphere exchange of ammonia (NH3) and CO2 uptake and transpiration by vegetation. In doing so, we study relationships useful for the improvement and development of NH3 flux representations in models. The NH3 concentration and flux are measured using a novel open-path miniDOAS (differential optical absorption spectroscopy) measurement setup, taken during the 5-week Ruisdael Land–Atmosphere Interactions Intensive Trace-gas and Aerosol measurement (RITA-2021) campaign (25 August until 12 October 2021) at the Ruisdael Observatory in Cabauw, the Netherlands. After filtering for unobstructed flow, sufficient turbulent mixing and CO2 uptake, we find the diurnal variability in the NH3 flux to be characterized by daytime emissions (0.05 µgm-2s-1 on average) and deposition at sunrise and sunset (−0.05 µgm-2s-1 on average). We first compare the NH3 flux to the observed gross primary production (GPP), representing CO2 uptake, and latent heat flux (LvE), representing net evaporation. Next, we study the observations following the main drivers of the dynamic vegetation response, which are photosynthetically active radiation (PAR), temperature (T) and the water vapor pressure deficit (VPD). Our findings indicate the dominance of the stomatal emission of NH3, with a high correlation between the observed emissions and both LvE (0.70) and PAR (0.72), as well as close similarities in the diurnal variability in the NH3 flux and GPP. However, efforts to establish relationships are hampered by the high diversity in the NH3 sources of the active agricultural region and the low data availability after filtering. Our findings show the need to collocate meteorological, carbon and nitrogen studies to advance our understanding of NH3 surface exchange and its representation.

Patterns in acute aortic dissection and a connection to meteorological conditions in Germany.

Acute type A aortic dissection (ATAAD) is a dramatic emergency exhibiting a mortality of 50% within the first 48 hours if not operated. This study found an absolute value of cosine-like seasonal variation pattern for Germany with significantly fewer ATAAD events (Wilcoxon test) for the warm months of June, July, and August from 2005 to 2015. Many studies suspect a connection between ATAAD events and weather conditions. Using ERA5 reanalysis data and an objective weather type classification in a contingency table approach showed that for Germany, significantly more ATAAD events occurred during lower temperatures (by about 4.8 K), lower water vapor pressure (by about 2.6 hPa), and prevailing wind patterns from the northeast. In addition, we used data from a classification scheme for human-biometeorological weather conditions which was not used before in ATAAD studies. For the German region of Berlin and Brandenburg, for 2006 to 2019, the proportion of days with ATAAD events during weather conditions favoring hypertension (cold air advection, in the center of a cyclone, conditions with cold stress or thermal comfort) was significantly increased by 13% (Chi-squared test for difference of proportions). In contrast, the proportion was decreased by 19% for conditions associated with a higher risk for patients with hypotension and therefore a lower risk for patients with hypertension (warm air advection ahead of warm fronts, conditions with no thermal stress or heat stress, in the center of a cyclone with thermal stress). As many studies have shown that hypertension is a risk factor for ATAAD, our findings support the hypothesized relation between ATAAD and hypertension-favoring weather conditions.

Improving the estimation of atmospheric water vapor pressure using interpretable long short-term memory networks

Atmospheric water vapor pressure is an essential meteorological control on land surface and hydrologic processes. As it is not as frequently observed as other meteorologic conditions, it is often inferred through the August–Roche–Magnus formula by simply assuming dew point and daily minimum temperatures are equivalent or by empirically correlating the two temperatures using an aridity correction. The performance of both methods varies considerably across different regions and during different time periods; obtaining consistently accurate estimates across space and time remains a great challenge. Here, an interpretable Long Short-Term Memory (iLSTM) network conditioned on static, location specific attributes is proposed to estimate the daily vapor pressure. This approach allows for training a single transferable model using ensemble data from multiple sites and exploring the quantitative dependency of vapor pressure prediction on multiple environmental variables and their histories. To evaluate this approach, three iLSTM model configurations were developed, each considering different site attributes as static variables. For each configuration, multiple model realizations were trained using 83 FLUXNET sites in the United States and Canada, where each realization corresponds to different withheld groups of sites used for model evaluation. Results show that the iLSTM networks noticeably improve the estimation accuracy in comparison with the two assumption-based methods for most sites, reducing the failure rate from 32 % to 10.9 % for the best iLSTM model configuration. Additionally, this network provides reasonable insights into both the relative importance of the time-series input variables and their temporal importance. This method is found to be effective for imputing vapor pressure across space and time.

A Hybrid Deep Learning Algorithm for Tropospheric Zenith Wet Delay Modeling with the Spatiotemporal Variation Considered

The tropospheric Zenith Wet Delay (ZWD) is one of the primary sources of error in Global Navigation Satellite Systems (GNSS). Precise ZWD modeling is essential for GNSS positioning and Precipitable Water Vapor (PWV) retrieval. However, the ZWD modeling is challenged due to the high spatiotemporal variability of water vapor, especially in low latitudes and specific climatic regions. Traditional ZWD models make it difficult to accurately fit the nonlinear variations in ZWD in these areas. A hybrid deep learning algorithm is developed for high-precision ZWD modeling, which considers the spatiotemporal characteristics and influencing factors of ZWD. The Convolutional Neural Network (CNN) and Long Short-Term Memory (LSTM) are combined in the proposed algorithm to make a novel architecture, namely, the hybrid CNN-LSTM (CL) algorithm, combining CNN for local spatial feature extracting and LSTM for complex sequence dependency training. Data from 46 radiosonde sites in South America spanning from 2015 to 2021 are used to develop models of ZWD under three strategies, i.e., model CL-A without surface parameters, model CL-B with surface temperature, and model CL-C introducing surface temperature and water vapor pressure. The modeling accuracy of the proposed models is validated using the data from 46 radiosonde sites in 2022. The results indicate that CL-A demonstrates slightly better accuracy compared to the Global Pressure and Temperature 3 (GPT3) model; CL-B shows a precision increase of 14% compared to the Saastamoinen model, and CL-C exhibits accuracy improvements of 30% and 12% compared to the Saastamoinen and Askne and Nordius (AN) model, respectively. Evaluating the models’ generalization capabilities at non-modeled sites in South America, data from six sites in 2022 were used. CL-A shows overall better performance compared to the GPT3 model; CL-B’s accuracy is 19% better than the Saastamoinen model, and CL-C’s accuracy is enhanced by 33% and 10% compared to the Saastamoinen and AN model, respectively. Additionally, the proposed hybrid algorithm demonstrates a certain degree of improvement in both modeling accuracy and generalization accuracy for the South American region compared to individual CNN and LSTM algorithm.