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This study presents experimental analysis and numerical modeling of hygroscopic moisture buffering by paper and books. First, a literature review of moisture transport properties of paper is presented. Experimental work on two paper types includes SEM analysis of the paper structure, determination of sorption isotherms and water vapor permeability measurements. A hysteretic model for paper is presented, which is based on the measurement of the main adsorption and desorption curves. It is shown that the water vapor permeability in a hysteretic model is dependent on the moisture content and not on the relative humidity. Books consist of several paper sheets with air layers between the sheets. To take the air layers into account, a parallel transport model is proposed to determine the effective moisture transport properties of books taking into account the air layers. The dynamic hygroscopic behavior of small book samples was measured. It is shown that, although the water vapor permeability of different paper types can be quite different, the effusivity of a book highly depends on the presence of the air layers and can therefore remain comparable for different paper types. [ABSTRACT FROM AUTHOR]

Abstract: This study describes the use of cassava starch acetate (CSA) to impregnate Kraft paper and its influence on the water vapor permeability (K w). This barrier property depends on the water vapor diffusion coefficient (D eff) and the material hygroscopicity properties (adsorptivity, β). The influences of D eff and β on the K w value were studied. Kraft paper samples were impregnated at atmospheric pressure and under vacuum. The results showed an important decrease on the K w values, which was associated with two factors: (a) the partial filling of the Kraft paper superficial and internal pores by the impregnated CSA, reducing the K w; (b) as CSA is much less hygroscopic than paper, its adsorptivity is reduced significantly by impregnation. This paper demonstrates that CSA impregnation of Kraft paper is an interesting alternative for the improvement of the hygroscopic properties and water vapor permeability of the Kraft paper. [Copyright &y& Elsevier]

Abstract Measurements have been performed to clarify the connection between fibre–fibre joint properties and dimensional stability using laboratory sheets prepared from never-dried fibres, from heavily hornified fibres having a low molecular contact area between the fibres, and from both hornified and never-dried fibres treated with a polyelectrolyte multilayer (PEM) technique to increase the molecular contact area in the fibre–fibre joint. The influence of the drying mode, i.e. whether the sheets are dried freely or under restraint, was also evaluated. The results showed that neither paper strength nor fibre–fibre joint contact area had any significant influence on the dimensional stability of sheets dried under restraint. On the other hand, when the sheets were dried freely, the PEM-treated sheets expanded to the same extent as, or to an even greater extent than the non-PEM-treated sheets, even though they adsorbed less water for a given change in relative humidity. There was also a correlation between drying shrinkage and dimensional stability, where greater shrinkage was associated with a greater hygroexpansion in the freely dried sheets. [ABSTRACT FROM AUTHOR]

The hygroexpansion of paper was significantly reduced, up to 28% lower amplitude of change when the paper was subjected to a change in relative humidity from 20 to 85% RH, by oxidation of the fibre wall. Never-dried bleached kraft fibres were oxidised with sodium periodate, which specifically oxidises the C2–C3 bond of 1,4-glucans so that the cellulose is partly converted into dialdehyde cellulose. Since both the dry and wet strength of laboratory sheets were significantly improved, the dry tensile strength increased from 24 kNm/kg up to 66 kNm/kg and the relative wet tensile strength increased from 1.5% up to 40%, it is suggested that the aldehydes form hemiacetal linkages within the fibre wall during the consolidation and drying of the sheets. The mechanical, hygroexpansive and moisture sorptive properties of the sheets made from the oxidised fibres were studied. The results showed that the main reason for the reduced hygroexpansion was a decrease in moisture sorptivity, i.e. when the sheets made of fibres with different degrees of cross-linking were subjected to the same change in relative humidity, the more cross-linked fibres showed a smaller change in moisture content. It was also shown that the hygroexpansion coefficient, i.e. the moisture-normalised dimensional change, was not significantly changed by the periodate oxidation, i.e. indicating that there are no improvement in dimensional stability if the paper is subjected to a specific amount of water. [ABSTRACT FROM AUTHOR]

Abstract: Thermal degradation of lignocellulosic materials has been studied widely because of its importance in several applications. While a variety of thermal treatment setups has been proposed, this paper introduces a thermal treatment method where high temperature is combined with presence of water vapor in an atmospheric oven chamber. The performance of the device was evaluated at temperature and volume fraction of water vapor ranges of 175–300 °C and 1–98%, respectively. The impact of the treatment was assessed by observing the changes in paper sheets, specifically brightness, light absorption coefficient, burst strength, ultraviolet resonance Raman spectra and the degree of polymerization of cellulose. The results demonstrated that the adapted thermal treatment device functions within the tested ranges of temperature and volume fraction of water vapor. In this study water vapor was found to accelerate hydrolytic thermal degradation of fully bleached paper sheets in terms of thermal yellowing and strength deterioration. In contrast, the empirical findings with lignin-containing paper provided new information on how the residual lignin increases its resistance towards water vapor introduced thermal degradation. This was demonstrated by the results of ultraviolet resonance Raman spectra and light absorption coefficient, which suggested that the thermal degradation of lignin is substantially enhanced in the presence of oxygen. [Copyright &y& Elsevier]

Abstract: In this paper a simplified network model for mechano-sorptive creep is presented, which is a further development of an earlier paper [Strömbro, J., Gudmundson, P., 2008. Mechano-sorptive creep under compressive loading – a micromechanical model. International Journal of Solids and Structures 45 (9), 2420–2450.]. It is assumed that the anisotropic hygroexpansion of the fibres leads to large stresses at the fibre bonds when the moisture content changes. The resulting stress state will accelerate creep if the fibre material obeys a constitutive law that is non-linear. Fibre kinks are included in order to capture experimental observations of larger mechano-sorptive effects in compression than in tension. Moisture dependent material parameters and anisotropy in the fibre distribution have been introduced. Theoretical predictions based on the model are compared to experimental results for an anisotropic paper both under tensile and compressive loading at varying moisture content and it is found that the important features in the experiments are captured by the model. Different kinds of drying conditions have also been examined. [Copyright &y& Elsevier]

In this study, a microcapsule that produces color in response to moisture in air was produced for use in an intelligent functional paper which is able to self-color after a fixed time. This microcapsule containing FeSO4 as the coloring material was prepared from gelatin and terephthaloyl chloride by an interfacial polymerization technique and was modified by a 2-propanol solution of glycerin to supplement the moisture sensitivity. A microcapsule membrane was formed by crosslinking between the amino group at the end of the gelatin and the carbonyl group of the terephthaloyl chloride. The time required for the microcapsules to produce the color tended to increase with decreasing amounts of the glycerin 2-propanol solution used for the soaking treatment of the microcapsules or increasing amounts of FeSO4 in the microcapsules. [ABSTRACT FROM AUTHOR]

When making food packages from fiber-based, extrusion-coated materials, water vapor transmission rate (WVTR) of the material is one of the key factors defining the shelf life of the product. The WVTR test is commonly a time-consuming procedure that delays progress in project development. In this study, a calculation method for WVTR-determinations was devised that can reduce the amount of testing and thus enhance the speed of research. Furthermore, the effect of atmospheric conditions on the permeation of water vapor through packaging materials is an important factor in view of the use of food packages all over the world. In this study, it was found that the combined effects of both relative humidity and temperature resulted in an almost linearly increasing WVTR as a function of mixing ratio under the given atmospheric conditions. [ABSTRACT FROM AUTHOR]

Indirect evaporative cooling, by using water evaporation to absorb heat to lower the air temperature without adding moisture, is an extremely low energy and environmentally friendly cooling principle. The properties of the wet channel surface in an indirect evaporating cooler, i.e. its moisture wicking ability, diffusivity and evaporation ability, can greatly affect cooling efficiency and performance. Irregular fibres help to divert moisture and enlarge the wetted area, thus promoting evaporation. A range of fabrics (textiles) weaved from various fibres were experimentally tested and compared to Kraft paper, which has been conventionally used as a wet surface medium in evaporative coolers. It was found that most of the textile fabrics have superior properties in moisture wicking ability, diffusivity and evaporation ability. Compared with Kraft paper, the wicking ability of some fabrics was found to be 171%–182% higher, the diffusion ability 298%–396% higher and evaporation ability 77%–93% higher. A general assessment concerning both the moisture transfer and mechanical properties found that two of the fabrics were most suitable for indirective evaporative cooling applications. [ABSTRACT FROM AUTHOR]

Space exploration presents vast prospects for scientific, industrial, and economic progress. This paper introduces the MeSat mission as a pioneering approach to Mars exploration. The MeSat aims to deepen our understanding of Martian conditions and resources by employing an optimized Earth-to-Mars trajectory, enabling a comprehensive study of the Martian atmosphere and surface. The mission comprises a cargo microsatellite hosting three 6U CubeSats and two 3U CubeSats, deployed into four separate Mars orbits to form a constellation. Each CubeSat carries distinct payloads: a THz radiometer for Martian water vapor atmospheric observation, a high-resolution surface camera, a high-tech spectrometer, and a Fourier transform spectrometer (FTS) for wind speed readings. This paper includes the majority of the key parameters; however, we focus our discussion more on two aspects of this pioneering mission: the first aspect contains the proposal of four distinct payloads for the study of Mars' atmosphere and the second aspect proposes an optimal mission design algorithm that analyzes a fuel-efficient low-thrust trajectory from Earth to Mars. Regarding the payloads, the THz radiometer requires a specific design; hence, we explain this payload in more depth; the rest of the payloads, we suggest utilizing commercially available elements for the cost-effective manufacture of a whole system. For mission trajectory optimization, the study employs a dual-step hybrid optimization algorithm (PSO-homotopy) to analyze fuel-efficient low-thrust trajectories from Earth to Mars, incorporating the ephemeris dynamics model to account for gravitational perturbations in the entire Solar System. In practical mission design, crucial factors like hyperbolic excess velocity, diverse opportunities for Earth launch and Mars rendezvous, varied propulsion systems, and time of flight (TOF) play vital roles in trajectory optimization. In summary, for the MeSat mission, we propose a comprehensive Mars environmental mission design. We consider all aspects of the mission from trajectory design to engineering detail design, since we would like to inspire future Mars missions with a complete report. [ABSTRACT FROM AUTHOR]

This paper studies a new concept of using global navigation satellite system (GNSS) signals coherently reflected over relatively smooth ocean and ice surfaces from very low elevation angles (below ∼8°) and received by low Earth orbit (LEO) satellites to retrieve the tropospheric information. This approach can provide horizontal profiles of tropospheric zenith delay and total column water vapor (TCWV) with centimeter‐level high precision and spatial resolutions of tens of km by ∼1 km, depending on the elevation angle, with a sampling spacing of ∼100 m. This approach can potentially be applied to most sea ice and calm ocean areas and provide tropospheric sensing data, which can complement and augment existing observation systems. A few case studies are conducted in this paper using the Spire grazing‐angle GNSS‐R data. The retrieved TCWV is compared to ERA5 products and the Sentinel‐3 Ocean and Land Color Instrument measurements and shows promising performances. The errors associated with the GNSS‐R tropospheric measurements are also discussed. Plain Language Summary: The atmospheric water vapor is an important component for the weather and climate systems and is difficult to measure, especially over ocean and ice surfaces. This paper studies a new approach to measuring atmospheric water vapor using global navigation satellite system (GNSS) signals reflected off ocean and ice surfaces. If the reflection is from a low elevation angle (below ∼8°) and the reflected signal is coherent (all signal rays are reflected in the same direction), this approach can provide very high precision observation of the horizontal gradients of the tropospheric delay and the vertically integrated atmospheric water vapor with good spatial resolutions. This paper presents the methodology of the proposed approach and a few case studies to demonstrate the feasibility and performance by comparing the GNSS‐R retrieved water vapor measurements with models and the Sentinel‐3 satellite radiometry measurements. The errors associated with the GNSS Reflectometry (GNSS‐R) tropospheric measurements are also discussed. Key Points: A new tropospheric sensing concept is studied that relies on coherent‐reflection global navigation satellite system (GNSS) signals off ocean and ice surfacesAlgorithms are developed and demonstrated using Spire grazing‐angle GNSS‐R data to retrieve tropospheric delay and water vaporThe presented approach provides high‐precision tropospheric delay and total column water vapor horizontal profiles, as validated using the Sentinel‐3 Ocean and Land Color Instrument data [ABSTRACT FROM AUTHOR]

A new microwave satellite water vapour retrieval for use in polar winter conditions is presented. The retrieval employs a priori information and an iterative approach. It is tested using simulated and actual measurements from the Microwave Humidity Sounder (MHS) satellite instruments. Ground truth is provided by the G-band vapor radiometer (GVR) at Barrow, Alaska. For water vapour columns less than 6kgm-2, comparison with the GVR gives a standard deviation of 0.39kgm-2 and a systematic bias of 0.08kgm-2. The errors are shown to be significantly less than for other satellite measurement systems. The errors are comparable to those from atmospheric reanalyses; however, the MHS data come at much higher horizontal resolution (< 40km) and are shown to reveal more structure. The retrieval can be used to obtain pan-Arctic maps of water vapour columns of unprecedented quality. The retrieval may also be applied to the Special Sensor Microwave Imager/Sounder (SSMIS) and the Advanced Technology Microwave Sounder (ATMS). [ABSTRACT FROM AUTHOR]

Two independently derived SCIAMACHY total water vapour column (WVC) products are compared with integrated water vapour data calculated from radiosonde measurements, and with each other. The two SCIAMACHY WVC products are retrieved with two different retrieval algorithms applied in the visible and short wave infrared wavelength regions respectively. The first SCIAMACHY WVC product used in the comparison is ESA's level 2 version 5.01 WVC product derived with the Air Mass Corrected Differential Absorption Spectroscopy (AMC-DOAS) retrieval algorithm (SCIAMACHYESA). The second SCIAMACHY WVC product is derived using the Iterative Maximum Likelihood Method (IMLM) developed by Netherlands Institute for Space Research (SCIAMACHY-IMLM). Both SCIAMACHY WVC products are compared with collocated water vapour amounts determined from daily relative humidity radiosonde measurements obtained from the European Centre for Medium-Range Weather Forecasts (ECMWF) radiosonde network, over an 18 month and 2 yr period respectively. Results indicate a good agreement between theWVC amounts of SCIAMACHY-ESA and the radiosonde, and a mean difference of 0.03 g cm-2 is found for cloud free conditions. Overall the SCIAMACHY-ESA WVC amounts are smaller than the radiosonde WVC amounts, especially over oceans. For cloudy conditions the WVC bias has a clear dependence on the cloud top height and increases with increasing cloud top heights larger than approximately 2 km. A likely cause for this could be the different vertical profile shapes of water vapour and O2 leading to different relative changes in their optical thickness, which makes the AMF correction method used in the algorithm less suitable for high clouds. The SCIAMACHY-IMLM WVC amounts compare well to the radiosonde WVC amounts during cloud free conditions over land. A mean difference of 0.08 g cm-2 is found which is consistent with previous results when comparing daily averaged SCIAMACHY-IMLM WVC amounts with ECMWF model data globally. Furthermore, we show that the measurements for cloudy conditions (cloud fraction ≥0.5) with low clouds (cloud pressure ≥930 hPa) above the ocean and land compare quite well with radiosonde data. [ABSTRACT FROM AUTHOR]

Retrieving time series of atmospheric constituents from ground-based spectrometers often requires different temporal averaging depending on the altitude region in focus. This can lead to several datasets existing for one instrument which complicates validation and comparisons between instruments. This paper puts forth a possible solution by incorporating the temporal domain into the maximum a posteriori (MAP) retrieval algorithm. The state vector is increased to include measurements spanning a time period, and the temporal correlations between the true atmospheric states are explicitly specified in the a priori uncertainty matrix. This allows the MAP method to effectively select the best temporal smoothing for each altitude, removing the need for several datasets to cover different altitudes. The method is compared to traditional averaging of spectra using a simulated retrieval of water vapour in the mesosphere. The simulations show that the method offers a significant advantage compared to the traditional method, extending the sensitivity an additional 10 km upwards without reducing the temporal resolution at lower altitudes. The method is also tested on the OSO water vapour microwave radiometer confirming the advantages found in the simulation. Additionally, it is shown how the method can interpolate data in time and provide diagnostic values to evaluate the interpolated data. [ABSTRACT FROM AUTHOR]

Middle atmospheric water vapour can be used as a tracer for dynamical processes. It is mainly measured by satellite instruments and ground-based microwave radiometers. Ground-based instruments capable of measuring middle atmospheric water vapour are sparse but valuable as they complement satellite measurements, are relatively easy to maintain and have a long lifetime. MIAWARA-C is a ground-based microwave radiometer for middle atmospheric water vapour designed for use on measurement campaigns for both atmospheric case studies and instrument intercomparisons. MIAWARA-C's retrieval version 1.1 (v1.1) is set up in a way to provide a consistent data set even if the instrument is operated from different locations on a campaign basis. The sensitive altitude range for v1.1 extends from 4 hPa (37 km) to 0.017 hPa (75 km). MIAWARA-C measures two polarisations of the incident radiation in separate receiver channels and can therefore provide two independent measurements of the same air mass. The standard deviation of the difference between the profiles obtained from the two polarisations is in excellent agreement with the estimated random error of v1.1. In this paper, the quality of v1.1 data is assessed during two measurement campaigns: (1) five months of measurements in the Arctic (Sodankylä, 67.37° N/26.63° E) and (2) nine months of measurements at mid-latitudes (Zimmerwald, 46.88° N/7.46° E). For both campaigns MIAWARA-C's profiles are compared to measurements from the satellite experiments Aura MLS and MIPAS. In addition, comparisons to ACE-FTS and SOFIE are presented for the Arctic and to the ground-based radiometer MIAWARA for the mid-latitudinal campaign. In general all intercomparisons show high correlation coefficients, above 0.5 at altitudes above 45 km, confirming the ability of MIAWARA-C to monitor temporal variations on the order of days. The biases are generally below 10% and within the estimated systematic uncertainty of MIAWARA-C. No consistent wet or dry bias is identified for MIAWARA-C. In addition, comparisons to the reference instruments indicate the estimated random error of v1.1 to be a realistic measure of the random variation on the retrieved profile. [ABSTRACT FROM AUTHOR]

Vertical profiles of water vapor (H2O) and its isotope ratio D=H expressed as δD(H2O) were measured in situ by the ISOWAT II diode-laser spectrometer during the MUltiplatform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA) airborne campaign. We present recent modifications of the instrument design. The instrument calibration on the ground as well as in flight is described. Based on the calibration measurements, the humidity-dependent uncertainty of our airborne data is determined. For the majority of the airborne data we achieved an accuracy (uncertainty of the mean) of ▵(δD) ≈10 %°. Vertical profiles between 150 and ∼ 7000m were obtained during 7 days in July and August 2013 over the subtropical North Atlantic Ocean near Tenerife. The flights were coordinated with ground-based (Network for the Detection of Atmospheric Composition Change, NDACC) and space-based (Infrared Atmospheric Sounding Interferometer, IASI) FTIR remote-sensing measurements of δD(H2O) as a means to validate the remote sensing humidity and δD(H2O) data products. The results of the validation are presented in detail in a separate paper (Schneider et al., 2014). The profiles were obtained with a high vertical resolution of around 3 m. By analyzing humidity and δD(H2O) correlations we were able to identify different layers of airmasses with specific isotopic signatures. The results are discussed. [ABSTRACT FROM AUTHOR]

We present a new algorithm for satellite retrievals of the atmospheric water vapor column in the blue spectral range. The water vapor absorption cross section in the blue spectral range is much weaker than in the red spectral range. Thus the detection limit and the uncertainty of individual observations is systematically larger than for retrievals at longer wavelengths. Nevertheless, water vapor retrievals in the blue spectral range have also several advantages: since the surface albedo in the blue spectral range is similar over land and ocean, water vapor retrievals are more consistent than for longer wavelengths. Compared to retrievals at longer wavelengths, over ocean the sensitivity for atmospheric layers close to the surface is higher due to the (typically 2 to 3 times) higher ocean albedo in the blue. Water vapor retrievals in the blue spectral range are also possible for satellite sensors, which do not measure at longer wavelengths of the visible spectral range like the Ozone Monitoring instrument (OMI). We investigated details of the water vapor retrieval in the blue spectral range based on radiative transfer simulations and observations from the Global Ozone Monitoring Experiment 2 (GOME-2) and OMI. It is demonstrated that it is possible to retrieve the atmospheric water vapor column density in the blue spectral range over most parts of the globe. The findings of our study are of importance also for future satellite missions like e.g. Sentinel 4 and 5 [ABSTRACT FROM AUTHOR]

The article focuses on a study which aims at analyzing the effect of atmospheric water vapor in detecting turbulence based on the Thorpe method. It describes the Thorpe method in which potential temperature and density are sorted in ascending order. It concludes increase in turbulent faction of the troposphere during saturation of atmospheric water vapor.

The article focuses on a study on water vapour spectroscopy and its impact on the ratio of heavy water (HDO) and water (H2O) in Scanning Imaging Absorption spectrometer for Atmospheric Cartography (SCIAMACHY). In the study,the impact of updated water spectroscopy is tested on total column retrievals of high-resolution Fourier-Transform Spectrometers (FTS). It shows negative shift in the HDO/H2O ratio for both the SCHIAMACHY and FTS measurements.

The article presents a study which investigates the quantification of water vapour retrieval uncertainties based on the near infrared measurements of the upcoming instruments. The study used optimal estimation theory to estimate the error in retrieval of hypothetical total water vapour column for 27 various atmospheric cases. Study reveals the range of errors from very dry to humid cases with very high surface albedo and the increase in uncertainties with higher optical thickness of aerosol.

The article discusses the use of off-axis integrated cavity output spectroscopy to evaluate continuous water vapor isotope measurements. It examines the accuracy and precision of the laser based water vapor isotope instrument through a comparison of measurements with those found using the conventional cold trap method. The application of a commercially available water vapor isotope analyzer (WVIA) is also discussed.

The article focuses on a study which aims to investigate if the absorption features of methane, carbon monoxide, and water vapour are adequately known using Sentinel-5 Precursor (S5P) satellite platform's TROPOspheric Monitoring Instrument (TROPOMI). TROPOMI will observe methane and carbon monoxide concentrations in the Earth's atmosphere by assessing spectra of back-scattered sunlight in the short-wave infrared. The application of two ground-based Fourier transform spectrometers is discussed.

We evaluate the isotopic composition of water vapor and precipitation simulated by the LMDZ GCM over Siberia using several datasets: TES and GOSAT satellite observations of tropospheric water vapor, GNIP and SNIP precipitation networks, and daily, in-situ measurements of water vapor and precipitation at the Kourovka site in Western Siberia. We use dD vs. humidity diagrams to explore the complementarity of these two variables to interpret model biases in terms of the representation of processes. LMDZ captures the spatial, seasonal and daily variations reasonably well. It systematically overestimates dD in the vapor and precipitation, a bias that is most likely associated with a misrepresentation of air mass origin. The performance of LMDZ is put in the context of other isotopic models from the SWING2 models. There is significant spread among models in the simulation of dD, and of the dD vs. humidity relationship. This confirms that dD brings additional information compared to humidity only. We specifically investigate the added value of water isotopic measurements to interpret the warm and dry bias feature by most GCMs over mid and high latitude continents in summer. LMDZ simulates the strongest dry bias on days when it simulates the strongest enriched bias in dD. The analysis of the slopes in dD vs. humidity diagrams and of processes controlling dD and humidity variations suggests that the cause of the moist bias could be either a problem in the large-scale advection transporting too much dry and warm air from the south, or insufficient surface evaporation. [ABSTRACT FROM AUTHOR]

The Fourier-transform spectrometer on board the Japanese GOSAT satellite offers an excellent opportunity to study the impact of instrument resolution on retrieval accuracy of CO2 and CH4. This is relevant to further improve retrieval accuracy and to optimize the cost-benefit ratio of future satellite missions for the remote sensing of greenhouse gases. To address this question, we degrade GOSAT measurements with a spectral resolution of ≈ 0.24 cm-1 step-by-step to a resolution of 1.5cm-1. We examine the results by comparing relative differences at various resolutions, by referring the results to reference values from the Total Carbon Column Observing Network (TCCON), and by calculating and inverting synthetic spectra for which the true CO2 and CH4 columns are known. The main impacts of degrading the spectral resolution turn out to be consistent for the first two approaches; pure forward model errors identified with simulated measurements are much smaller. For GOSAT spectra, the most notable effect on CO2 retrieval accuracy is the increase of the standard deviation of retrieval errors from 0.7% to 1.0% when the spectral resolution is reduced by a factor of six. The retrieval biases against atmospheric water abundance and airmass become stronger with decreasing resolution. The error scatter increase for CH4 columns is less pronounced. The selective degradation of single spectral windows demonstrates that the retrieval accuracy of CO2 and CH4 is dom inated by the spectral range where the absorption lines of the target molecule are located. For both GOSAT and synthetic measurements, retrieval accuracy decreases with lower spectral resolution, suggesting increasing interference errors. [ABSTRACT FROM AUTHOR]

The Global Precipitation Measurement (GPM) Mission Core Observatory satellite launched in 2014 as a joint mission between National Aeronautics and Space Administration (NASA) and JAXA. Global Precipitation Measurement (GPM) has, since that time, provided continuous, valuable dual‐frequency radar and passive microwave radiometer observations. Here, we introduce a gridded data set of collocated GPM Core Observatory observational products merged with a reanalysis‐derived Atmospheric river (AR) data set in the North Atlantic and North Pacific sectors. The three data sets that are merged and gridded are: (a) the NASA Goddard Profiling (GPROF) precipitation product, which uses GPM passive microwave radiometer observations to derive surface precipitation rates, (b) a water vapor data product derived from the GPM Core Observatory radiometer, provided by Remote Sensing Systems (RSS), and (c) the Mattingly et al. (2018, https://doi.org/10.1029/2018jd028714) AR data set that is specifically tuned to the high‐latitude regions. This novel merged data set spans from May 2014 to December 2022 with plans to update annually through 2026 at minimum. This gridded product combines RSS passive water vapor and precipitation estimates with coincident AR detection. This data product benefits the scientific community by providing (a) user‐friendly gridded satellite data compared to standard satellite data sets, while maintaining high temporal resolution, and (b) coincident satellite observations to assess the link between ARs and precipitation. Plain Language Summary: This paper summarizes the creation of a new, gridded data set containing precipitation, atmospheric water vapor content, and atmospheric river (AR) information from May 2014 to December 2022. The precipitation and water vapor data are both remotely‐sensed data products using the Global Precipitation Measurement Core Observatory Microwave Imager (GMI). The AR algorithm detection is more sensitive to moisture transport than global algorithms and is thus better suited to colder and drier environments. We temporally match and interpolate all data to a common grid and provide examples of the merged data to illustrate the seasonality and impacts of AR presence on precipitation. Lastly, we demonstrate the utility of this data set by investigating the assumptions used to estimate precipitation from GMI measurements. The data set confirms that ARs are associated with warmer temperatures, higher water vapor content, and more intense precipitation rates. Key Points: A new data set is presented that collocates satellite‐derived precipitation rates and water vapor with reanalysis‐derived Atmospheric rivers (ARs)Higher precipitation rates and water vapor content are coincident with AR events in the high‐latitude regionsAn example application illustrates warmer, more moist conditions during precipitating AR events that are present in the GPROF database [ABSTRACT FROM AUTHOR]

This study examines how different microphysical parameterization schemes influence orographically-induced precipitation and the distributions of hydrometeors and water vapour for mid-latitude summer conditions in the Weather Research and Forecasting (WRF) model. A high-resolution two-dimensional idealized simulation is used to assess the differences between the schemes in which a moist air flow is interacting with a bell-shaped 2 km high mountain. Periodic lateral boundary conditions are chosen to recirculate atmospheric water in the domain. It is found that the 13 selected microphysical schemes conserve the water in the model domain. The gain or loss of water is less than 0.81% over a simulation time interval of 61 days. The differences of the microphysical schemes in terms of the distributions of water vapour, hydrometeors and accumulated precipitation are presented and discussed. The Kessler scheme, the only scheme without ice-phase processes, shows final values of cloud liquid water 14 times greater than the other schemes. The differences among the other schemes are not as extreme, but still they differ up to 79% in water vapour, up to 10 times in hydrometeors and up to 64% in accumulated precipitation at the end of the simulation. The microphysical schemes also differ in the surface evaporation rate. The WRF singlemoment 3-class scheme has the highest surface evaporation rate compensated by the highest precipitation rate. The different distributions of hydrometeors and water vapour of the microphysical schemes induce differences up to 49Wm-2 in the downwelling shortwave radiation and up to 33Wm-2 in the downwelling longwave radiation. [ABSTRACT FROM AUTHOR]

A new fast clear-sky model called McClear was developed to estimate the downwelling shortwave direct and global irradiances received at ground level under clear skies. McClear implements a fully physical modelling replacing empirical relations or simpler models used before. It exploits the recent results on aerosol properties, and total column content in water vapor and ozone produced by the MACC project (Monitoring Atmosphere Composition and Climate). It accurately reproduces the irradiance computed by the libRadtran reference radiative transfer model with a computational speed approximately 105 times greater by adopting the abaci, or look-up tables, approach combined with interpolation functions. It is therefore suited for geostationary satellite retrievals or numerical weather prediction schemes with many pixels or grid points, respectively. McClear irradiances were compared to 1min measurements made in clear-sky conditions in several stations within the Baseline Surface Radiation Network in various climates. For global, respectively direct, irradiance, the correlation coefficient ranges between 0.95 and 0.99, resp. 0.86 and 0.99. The bias is comprised between -14 and 25Wm-2, resp. -49 and +33Wm-2. The RMSE ranges between 20Wm-2 (3% of the mean observed irradiance) and 36Wm-2 (5 %), resp. 33Wm-2 (5%) and 64W m-2 (10 %). These results are much better than those from state-of-the-art models. This work demonstrates the quality of the McClear model combined with MACC products, and indirectly the quality of the aerosol properties modeled by the MACC reanalysis [ABSTRACT FROM AUTHOR]

The Special Issue includes seven papers belonging to different areas of time series homogenization and data quality improvement. Climate research requires a large amount of fairly accurate observed climatic data. Recent method comparison tests of the Spanish MULTITEST project showed that ACMANT (Applied Caussinus-Mestre Algorithm for the homogenization of Networks of Time series) is likely the most accurate homogenization method for a quite wide range of homogenization tasks. [Extracted from the article]

The article presents a study which investigates the deuterated water/water (HDO/H2O) ratio retrievals from Greenhouse Gases Observing SATellite (GOSAT) launched by the Japanese Space Agency in 2009. The study used thermal and near infrared sensor for carbon observations-fourier transform spectrometer (TANSO-FTS), cloud and aerosol imager (TANSO-CAI), and thermal infrared (TIR). Results show that the retrieval of HDO/H2O ratio was sensitive to parameters such as aerosols.

The article presents a study which shows the ability of ground-based water vapor Raman lidar measurements up to the upper troposphere and lower stratosphere. The study described the data analysis, profile retrieval and calibration procedures in the Measurements of Humidity in the Atmosphere and Validation Experiments (MOHAVE) 2009. Results show the capability of lidar in measuring vapor with a precision of 10% and accuracy of 5 % from 1 kilometer above the ground to the lower stratosphere.

A global time series of total columnar water vapour from combined data of the Medium Resolution Imaging Spectrometer (MERIS) onboard ESA's Environmental Satellite (ENVISAT) and the Special Sensor Microwave/Imager (SSM/I) onboard the satellite series of the US Defense Meteorological Satellite Program (DMSP) is presented. The unique dataset, generated in the framework of the ESA Data User Element (DUE) GlobVapour project, combines atmospheric water vapour observations over land and ocean, derived from measurements in the near infrared and the microwave range, respectively. Daily composites and monthly means of total columnar water vapour are available as global maps on rectangular latitude-longitude grids with a spatial resolution of 0.05° ×0.05° over land and 0.5° ×0.5° over ocean for the years 2003 to 2008. The data is stored in NetCDF files and is fully compliant with the NetCDF Climate Forecast convention. Through the combination of high quality microwave observations and near infrared observations over ocean and land surfaces, respectively, the dataset provides global coverage. The combination of both products is carried out such that the individual properties of the microwave and near-infrared products, in particular their uncertainties, are not changed and therefore well defined. Due to the global coverage and the provided uncertainty estimates this data set is potentially of high value for climate research. The SSM/I-MERIS TCWV data set is freely available via the GlobVapour project web page with associated doi (doi:10.5676/DFE/WV_COMB/FP). In this paper, the details of the dataset generation, i.e. the satellite data used, the retrieval techniques and merging approaches are presented. The derived level 3 products are compared to global radiosonde data from the GCOS upper air network (GUAN), showing a high agreement with a root mean square deviation of roughly 4.4 kgm-2 and a small wet bias well below 1 kgm-2. Furthermore, the data set is shown to be free of seasonal biases. The consistency of the MERIS and SSM/I retrievals is demonstrated by applying the MERIS retrieval to sun glint areas over ocean. [ABSTRACT FROM AUTHOR]

In network real‐time kinematic positioning of multi‐reference station, the spatial and temporal distribution of tropospheric delay is affected by both horizontal and elevation. The traditional modeling strategy of regional troposphere takes more consideration of the horizontal factor, and the incomplete consideration of the elevation factor will lead to the problem of reduced modeling accuracy, especially in the face of the scene with large regional height deviation. Based on the traditional linear interpolation method (LIM), a simple and effective height‐deviation compensation‐based linear interpolation method (HCLIM) for regional tropospheric is proposed. The modeling accuracy of troposphere and the positioning accuracy of user RTK in large height deviation region are significantly improved. The method was verified based on six experimental subnets with large height deviations from a provincial continuously operating GNSS reference stations network in central China. The results showed that: For GPS satellite modeling, compared with the traditional LIM method, the average modeling accuracy improvement rate of HCLIM method is (84.5%, 75.5%, 59.3%, 26.7%) in the elevation angle range of (10–30°/30–40°/40–50°/50–90°). For BDS satellite, the average modeling accuracy improvement rate of HCLIM method in the above four elevation angles is (83.3%, 70%, 50%, 23.5%). For the positioning performance of user RTK, The horizontal positioning accuracy and RTK fixing rate were similar under the two methods, while HCLIM method showed only slight improvement. However, in the U direction, LIM method showed obvious systematic bias, while HCLIM method showed consistent positioning accuracy, which was improved to 82.8% compared with LIM method. Plain Language Summary: In GNSS relative positioning, the positioning performance of user largely depends on the extent to which atmospheric deviations (ionospheric delay or tropospheric delay) are eliminated or weakened. Compared with the ionosphere, the temporal and spatial characteristics of troposphere are significantly different. It is part of the lower atmosphere, extends from the Earth's surface to an altitude of about 20 km, and contains most of the atmospheric water vapor. The delay of satellite signals through the troposphere is affected by both horizontal and elevation. The traditional tropospheric regional modeling strategy only uses plane coordinates for interpolation, ignoring the influence of elevation factors or the consideration of height‐deviation is not perfect. When the height difference between the reference station and the rover station is large, the modeling accuracy will obviously be reduced. The large modeling residual may bring systematic deviation to the user coordinates, especially the elevation direction component. In this paper, we propose a regional tropospheric linear interpolation method (HCLIM) considering height deviation compensation. This method is simple and effective, The modeling accuracy of troposphere and the positioning accuracy of user RTK in large height difference region are significantly improved. Key Points: A simple and effective height‐deviation compensation‐based linear interpolation method (HCLIM) for regional tropospheric is proposedThe HCLIM method greatly improves the tropospheric modeling accuracy of each elevation angle range in the large height difference site areaThe HCLIM method significantly improves the systematic bias in elevation direction of user RTK positioning due to modeling residuals [ABSTRACT FROM AUTHOR]

Tritium waste deposition in air-unsaturated groundwater zones poses great challenges to optimal water allocation. This paper reviews the research progress of air-unsaturated-groundwater interaction. Traditional interaction studies typically model the fate and migration of pollutants in different regions. This can lead to biased results and simulation errors. The development of air-unsaturated-ground integrated modeling will be a breakthrough and a hotspot in tritium management. In this paper, the fate and migration of tritium leakage is further studied using the existing extended Environment Multimedia Modeling System (EEMMS). Moreover, to better understand its distribution in three zones, using tritium as a typical pollutant, it is necessary to consider its characteristics in different zones, especially its migration from unsaturated zones to groundwater and air zones. The result shows that the tritiated water vapor transfer in unsaturated groundwater areas decreases and part of the tritiated water vapor transfers to atmospheric areas as tritiated gas vapor. Compared with the analytical test accuracy (5 pCi mL−1), the accuracy of the tritium modeling using the finite element method can reach the minimum concentration limit of 0 pCi mL−1. The study of its distribution in air-unsaturated-groundwater zones can provide reference for other similar tritium management or NAPLs distribution across multimedia area. [ABSTRACT FROM AUTHOR]

This paper presents a theoretical description of diffusion growth of a gas bubble after its nucleation in supersaturated liquid solution. We study systems where gas molecules completely dissociate in the solvent into two parts, thus making Sievert’s solubility law valid. We show that the difference between Henry’s and Sievert’s laws for chemical equilibrium conditions causes the difference in bubble growth dynamics. Assuming that diffusion flux is steady we obtain a differential equation on bubble radius. Bubble dynamics equation is solved analytically for the case of homogeneous nucleation of a bubble, which takes place at a significant pressure drop. We also obtain conditions of diffusion flux steadiness. The fulfillment of these conditions is studied for the case of nucleation of water vapor bubbles in magmatic melts. [ABSTRACT FROM AUTHOR]

The oceans are a key source of a number of atmospherically important volatile gases. The accurate and robust determination of trace gases in seawater is a significant analytical challenge, requiring reproducible and ideally automated sample handling, a high efficiency of seawater--air transfer, removal of water vapour from the sample stream, and high sensitivity and selectivity of the analysis. Here we describe a system that was developed for the fully automated analysis of dissolved very short-lived halogenated species (VSLS) sampled from an under-way seawater supply. The system can also be used for semi-automated batch sampling from Niskin bottles filled during CTD (Conductivity, Temperature, Depth) profiles. The essential components comprise of a bespoke, automated purge and trap (AutoP & T) unit coupled to a commercial thermal desorption and gas chromatograph--mass spectrometer (TD-GC-MS). The AutoP & T system has completed five research cruises, from the tropics to the poles, and collected over 2500 oceanic samples to date. It is able to quantify > 25 species over a boiling point range of 34-180 °C with Henry's Law coefficients of 0.018 and greater (CH2I2, k∞H dimensionless gas/aqueous) and has been used to measure organic sulfurs, hydrocarbons, halocarbons and terpenes. In the east tropical Pacific, the high sensitivity and sampling frequency provided new information regarding the distribution of VSLS, including novel measurements of a photolytically driven diurnal cycle of CH2I2 within the surface ocean water. [ABSTRACT FROM AUTHOR]

We present a simple method to generate a perturbed parameter ensemble (PPE) of a fully-coupled atmosphere-ocean general circulation model (AOGCM), HadCM3, without requiring flux-adjustment. The aim was to produce an ensemble that samples parametric uncertainty in some key variables and displays a similar range of behavior as seen in multi-model ensembles (MMEs). Six atmospheric parameters, a sea-ice parameter and an ocean parameter were jointly perturbed within a reasonable range to generate an initial group of 200 members. To screen out implausible ensemble members, 20 yr pre-industrial control simulations were run and members whose tempera10 ture response to the parameter perturbations was projected to be outside the range of 13.6±2 °C, i.e. near to the observed pre-industrial global mean, were discarded. 21 members, including the standard unperturbed model, were accepted, covering almost the entire span of the eight parameters, challenging the argument that without fluxadjustment parameter ranges would be unduly restricted. This ensemble was used in 3 experiments; a 800 yr pre-industrial, a 150 yr quadrupled CO2, and a 150 yr 1% CO2 rise per annum simulation. The behavior of the PPE for the pre-industrial control compared well to the CMIP3 ensemble for a number of surface and atmospheric column variables with the exception of a few members in the Tropics. However, we find that members of the PPE with low values of the entrainment rate coefficient show very large increases in upper tropospheric and stratospheric water vapor concentrations in response to elevated CO2 and some show implausibly high climate sensitivities, and as such some of these members will be excluded from future experiments with this ensemble. The outcome of this study is a PPE of a fully-coupled AOGCM which samples parametric uncertainty with a range of behavior similar to the CMIP3 ensemble and a simple methodology which would be applicable to other GCMs. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the development of an algorithm to retrieve atmospheric water vapour column from observations in Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS). The study has applied the algorithm to observations at the Mainz, Germany-based Max Planck Institute for Chemistry from March to August 2011. Study reveals that the retrieval of vertical column density (VCDs) of water in cloudy conditions serves as the algorithm's important advantage.

The article discusses a study which examines a low-cost solid state gas sensor (TGS 2600 from Figaro) for its suitability in measuring ambient concentrations of methane in the air on the low arctic at Toolik Lake in Alaska. It compares two sensors against a high-quality, off axis integrated cavity output spectrometer. The removal of relative humidity and temperature sensitivities is presented.

The article presents a study which measured thermal infrared (IR) radiances near 8 microns containing information on the vertical distribution of water vapor. The vertical distribution of water vapor, its minor isotopologues (HDO) and methane are key gases that can be used in investigating the water and carbon cycles. It show improvements in vertical resolution and reduction in uncertainties in estimating the trace gases from aura tropospheric emission spectrometer (TES).

The article focuses on the retrieval of tropospheric water vapour profiles from pressure broadened emission spectra by microwave radiometer. The tropospheric retrieval delivers tropospheric water vapour profiles up to seven kilometers (km) with sensitivity between three and seven km. The profiles that result from the experiment correspond well with balloon soundings up to seven km. The large differences between retrieval and in-situ is caused by large vertical gradients in the true profile.

The article presents a study which examines the efficacy of ground-based spectroradiometric measurements for atmospheric aerosols and water vapor in Zanjan, Iran. Based on Cimel CE318-2 sun-photometer analysis, it found that the average values of aerosol optical depth is reached up to 440 nanometers through direct-beam irradiance measurements of sunlight. Using the least-squares method, the log-log plot of aerosol optical depth and its wavelength.

Thermodynamic and liquid water profiles can be retrieved by a ground-based microwave radiometer (MWR) in nearly all weather conditions, which is useful for detecting mesoscale phenomena. This paper reviews the advances in remote sensing of atmospheric profiles and cloud properties by MWR in central China. Comparative studies indicate that MWR retrieval accuracy is different under various skies, especially those that decay under precipitation. The off-zenith method is proven to be capable of reducing the impact of precipitation and snow on MWR retrieval accuracy. Application studies demonstrate that MWR retrievals are helpful for early warning of rainstorms, hailstorms, and thunderstorms. Moreover, MWR retrievals provide a way to study cloud properties. The temporal variations of cloud occurrence frequency (COF) and liquid water path (LWP) are different for low, middle, and high clouds, and the vertical distribution of COF is also different in autumn and other seasons. Note that MWR can infer valid retrievals over the eastern Tibetan Plateau due to the weak precipitation over there. Also, cloud properties over the eastern Tibetan Plateau present differences from those over central China, and this is related to the different characteristics of atmospheric water vapor between these two regions. To bring more benefits for mechanism study and early warning of severe weather and numerical weather prediction, the decayed accuracy of MWR zenith retrievals under precipitation should be resolved. And combining MWR with other instruments is necessary for MWR application in detecting multi-layer clouds and ice clouds. [ABSTRACT FROM AUTHOR]

Using multiple observational and reanalysis data, this paper investigates the impact of the interdecadal shift in summer Arctic Oscillation (AO) on precipitation in East Asia, by removing ENSO influences. The results indicate that the lower-layer activity center of summer AO in Atlantic shifted eastward after the mid-1980s. This regime shift of summer AO has a significant impact on precipitation in East Asia. Before the mid-1980s, the key regions in which precipitation was affected by AO in East Asia were northern East Asia and Northeastern China and adjacent regions. After the mid-1980s, the key regions in which precipitation was affected by AO in East Asia were central Inner Mongolia and Southern China. The mechanism of precipitation changes can be attributed to changes in atmospheric circulation and water vapor transport related to AO changes. After the mid-1980s, the influence of AO on geopotential height over northern East Asia weakened; meanwhile, the impact of AO on geopotential height over China increased. Consistent with the changes in atmospheric circulation, water vapor transport in East Asia also underwent interdecadal changes before and after the mid-1980s. The differences in atmospheric circulation and water vapor transport in East Asia can be traced back to the North Atlantic. Before the mid-1980s, wave activity flux related to summer AO tended to propagate in high latitudes and subtropics; after the mid-1980s, the wave activity flux changed in its subtropical path and propagated eastward from the North Atlantic through the Middle East to China, significantly affecting the summer precipitation in China. [ABSTRACT FROM AUTHOR]

Since higher band of 5G handles the frequencies from 24 to 47 GHz near the basement of the millimeter-wave band and also Ka-band which uses the frequency from 27 to 40 GHz for satellite communication, in this work an antenna array is designed at the operating frequency of 31 GHz which is used for both of the applications. But, as this frequency falls in the millimeter-wave range, absorption of the millimeter-wave energy by water vapor to overcome the atmospheric attenuation is high in long-range communication systems and also it severely suffers from path loss during propagation because of the high frequency. To overcome these problems, a high gain antenna is essentially required. In this paper, a high gain 1 × 4 linear antenna array is designed using High Frequency SS simulation software at 31 GHz with the microstrip patch elements with Roggers/RT duroid 5880 as the substrate using the corporate feed technique. This proposed antenna is fabricated and gives a gain of 14.76 dB which is large as compared to other structures of antenna arrays with the same and more number of elements and obtains a return loss of − 43.12 dB at the 31 GHz operating frequency. A single patch antenna and 1 × 2 array antennas are also designed and fabricated. Simulated results of the three are verified with the measured results. [ABSTRACT FROM AUTHOR]

The article presents a study on the application of the Weather Research and Forecasting model with Chemistry (WRF-Chem) in simulations over South Asia along with meteorological configuration and evaluation. It mentions the assessment of temperature, water vapor and precipitation against radiosonde and satellite-borne observations from the atmospheric infrared sounder (AIS) and Tropical Rainfall Measuring Mission (TRMM). It also notes their increasing tendency with altitude.

The article presents a statistical study on the distribution of water vapor and cirrus cloud distributions using Raman lidar at La Reunion. It investigates the diurnal cycle of water vapor to analyze the data set having several long acquisition measurements. It also presents an analysis regarding the cirrus clouds and performs a classification showing three distinct classes.

The article presents a study which aims to measure turbulent water vapor fluxes with the use of a lightweight unmanned aerial vehicle (UAV) system. The study assessed turbulent properties and vertical latent heat fluxes using UAV and conducted co-spectral analysis. Results show the consistency of UAV in measuring heat fluxes and good agreement between measurements of heat fluxes made in the lower troposphere and the meteorological situation of a convective boundary layer.