Atmospheric Precipitable Water Research Articles

Spatial-temporal variation of water vapor scale height and its impact factors in different climate zones of China

Water vapor scale height reflects the vertical distribution of water vapor in the atmosphere, which is a vital parameter in tropospheric zenith wet delay (ZWD) modeling and GNSS meteorology. This study accurately calculated the long-term water vapor scale height using 89 radiosonde stations in China, analyzed the characteristics in temporal and spatial variations and explored the impact factors of the water vapor scale height from the perspective of the climate zones. The numerical results indicate that the water vapor scale height in China exhibits annual and semiannual variations with a rising-then-decreasing trend across the four seasons. A relatively larger value for the water vapor scale height were observed in the subtropical monsoon climate and the temperate continental climate zone, in which the values are greater than 2.35 km, while the values in temperate monsoon climate and the alpine plateau climate zone are relatively small. In addition, the water vapor scale height in different climate zones shows different trends, with a downward trend appeared in the subtropical monsoon climate and the alpine plateau climate zone, while an upward trend was observed in the temperate monsoon climate and the temperate continental climate zone. Furthermore, a positive correlation between water vapor scale height and temperature, pressure, and atmospheric precipitable water was found in China, with a varied degree of correlation in different climate zones.

Higher accuracy estimation of the weighted mean temperature (Tm) using GPT3 model with new grid coefficients over China

The weighted mean temperature (Tm) is an essential parameter in the field of Global Navigation Satellite System (GNSS) meteorology, as it enables the conversion of zenith wet delay to atmospheric precipitable water vapor (PWV). The existing Tm models, such as the GPT3 model, utilize the empirical annual and semi-annual amplitudes of Tm at grid points along with corresponding trigonometric functions to estimate Tm, making it difficult to provide a more detailed description of the daily variation of Tm. Therefore, the measured surface temperature and water vapor pressure were introduced to calculate the new series of grid coefficients using the least-square method, which enables the GPT3 model to estimate Tm with higher accuracy. In this process, the ERA5 reanalysis data derived from ECMWF from 2001 to 2010 was utilized to compute Tm values, and the new grid coefficient obtained by introducing only surface temperature was considered as scheme #1 and that achieved by introducing both surface temperature and surface water vapor pressure was regarded as scheme #2. The Tm data of 2023 calculated both by the radiosonde and ERA5 reanalysis data were utilized to assess the new grid coefficients for Tm estimation, and the results show that the grid coefficients based on these two surface parameters outperformed those only using the temperature. In the compassion using the ERA5 data, the bias/MAE/RMSE with the two types of new grid coefficients are −0.09/1.89/2.41 K and − 0.07/1.82/2.31 K, respectively, and the improvements reach to 50%/32.5%/34.2% and 61.1%/35%/36.9% compared with GPT3 model. In the comparison with radiosonde data, the scheme #1 and #2 performed a 0.55 K(13.8%) and 0.68 K(17.1%) improvement in the mean RMSE of stations compared with the GPT3 model. Note that the proposed two schemes can effectively improve the accuracy of estimating Tm in the comparison of regions, epochs and seasons with the Bevis and GPT3 model. Furthermore, the impact of Tm on PWV can be improved by the proposed two schemes, which was demonstrated using the theoretical RMSE and relative error of PWV.

Synoptic Analysis of Flood-Causing Rainfall and Flood Characteristics in the Source Area of the Yellow River

The source area of the Yellow River (SAYR) in China is an important water yield and water-conservation area in the Yellow River. Understanding the variability in rainfall and flood over the SAYR region and the related mechanism of flood-causing rainfall is of great importance for the utilization of flood water resources through the optimal operation of cascade reservoirs over the upper Yellow River such as Longyangxia and Liujiaxia, and even for the prevention of flood and drought disasters for the entire Yellow River. Based on the flow data of Tangnaihai hydrological station, the rainfall data of the SAYR region and NCEP-NCAR reanalysis data from 1961 to 2020, three meteorological conceptual models of flood-causing rainfall—namely westerly trough type, low vortex shear type, and subtropical high southwest flow type—are established by using the weather-type method. The mechanism of flood-causing rainfall and the corresponding flood characteristics of each weather type were investigated. The results show that during the process of flood-causing rainfall, in the westerly trough type, the mid- and high-latitude circulation is flat and fluctuating. In the low vortex shear type, the high pressures over the Ural Mountains and the Okhotsk Sea are stronger compared to other types in the same period, and a low vortex shear line is formed in the west of the SAYR region at the low level. The rain is formed during the eastward movement of the shear line. In the subtropical high southwest flow type, the low trough of Lake Balkhash and the subtropical high are stronger compared to other types in the same period. Flood-causing rainfall generally occurs in areas with low-level convergence, high-level negative vorticity, low-level positive vorticity, convergence of water vapor flux, a certain amount of atmospheric precipitable water, and low-level cold advection. In terms of flood peak increment and the maximum accumulated flood volume, the westerly trough type has a long duration and small flood volume, and the low vortex shear type and the subtropical high southwest flow type have a short duration and large flood volume.

Geochemistry of high temperature initial geothermal fluids in the Dabie orogenic belt

Analyzing the genesis and resource potential of orogenic geothermal systems poses significant challenges due to their complex geological backgrounds and evolutionary histories. This paper presents a novel synthesis of hydrogeochemical and isotope geochemical data, coupled with geological and geophysical results, to comprehensively understand the origins of deep, high-temperature orogenic geothermal systems. This understanding is achieved through the utilization of advanced geochemical modeling techniques to analyze the geochemical attributes of initial geothermal fluids. The hydrochemical and H/O/S isotopic composition of a total of 67 geothermal and non-geothermal water samples from the Dabie orogenic belt (DOB) were analyzed. Integrated multicomponent geothermometry (IMG) was employed to reconstruct the characteristics of the initial geothermal fluids, and PHREEQC inverse simulations creatively determined the most likely pathways of their genesis and evolution. The findings indicate that all geothermal waters from the three major geothermal fields of Luotian, Yingshan, and Yuexi are alkali-sulfate type waters. The initial geothermal fluids are acidic sulfate type with reservoir temperatures of 156–222 °C, 115–179 °C, and 100–189 °C, respectively. The primary processes responsible for the formation of these initial geothermal fluids are the dissolution of anhydrite from sulfide oxidation and, to a lesser extent, direct sulfide oxidation. Generally, the formation of geothermal systems in the investigated geothermal fields is associated with the extensional collapse and lithospheric thinning of the Dabie orogen since the Early Cretaceous Period. The spatial distribution of the three geothermal fields in this study corresponds to the tectonic-magmatic framework of magmatic intrusion-induced domes (Luotian and Yuexi) in the DOB. The reactivation of the Tan-Lu Fault during the Cenozoic Era suggests the presence of a deep heat source comprising magmatic and metamorphic components. This heat source, combined with the infiltration of paleo-atmospheric and modern atmospheric precipitation water along regional fault systems, results in the formation and gradual dilution of initial geothermal fluids. Neutralization occurs through interactions with calcite and fine-grained sodium aluminosilicates, ultimately leading to the formation of the collected geothermal water. The conceptual model established in this study elucidates the distinctive genesis and formation mechanism of the orogenic geothermal system exemplified by the DOB.

SHIFTING PROCESSES IN THE CITY OF DNIPRO AND DNIPROPETROVSK REGION

The analysis of landslide processes in the city of Dnipro and the Dnipropetrovsk region was carried out. It was found that landslides occupy a dominant position among exogenous geological processes due to their significant distribution, especially in the territories of intensive economic use. Their activation has significant negative consequences due to the speed of development and significant deformation and destruction of buildings and structures. The development of landslide processes on the territory of the city of Dnipro and the Dnipropetrovsk region is determined by the peculiarities of the geological and hydrogeological conditions of certain areas. The modern activation of landslides is associated with the manifestation of accompanying processes - erosion and abrasion. Also, the intensification of landslides is influenced by human economic activity, which is caused by additional loads, trimming of slopes during construction works, creation of dynamic loads, etc. The process of landslide formation on the right bank of the Dnieper and its right tributaries became particularly active. The total number of landslides and landslide areas is 382 units, of which 133 landslides are in the city of Dnipro. The largest number of landslides is observed in the cities of Dnipro and Kamianske. In the city of Dnipro, landslide-hazardous zones are located near ravines. Landslides occur in Aptekarska Balka due to the following reasons: increase in the steepness of the slope; washing slopes with water; weakening of rock strength due to waterlogging by atmospheric precipitation and underground water; construction and economic activity. One of the environmental problems of Aptekarska balka is the dumping of garbage into the beam. Along Aptekarska balka are the residential streets of Bohdanova and Tokarna, the buildings of which suffer the most from landslides. As a design proposal, it is proposed to strengthen the sliding slopes in Aptekarska Balka, Dnipro, by means of a retaining wall made of gabions.

Alteration Mechanism of Variscan Granite in a Project Area at the Northern Foot of the Tianshan Mountains, China

Long-term erosion of granite—a type of hard rock—by hydrothermal fluids and tectonic movement can lead to a fragmentation of the internal structure of the original rock, transfer/replacement of mineral elements, and alteration of the rock’s basic properties. Such changes can be problematic for the construction of water conservancy, hydropower, and road projects. This study adopted the altered Variscan granite in a water diversion project area at the northern foot of the Tianshan Mountains (China) as the research object, and explored the alteration mechanism using thin section identification, X-ray diffraction, major element analysis, and electron probe and oxygen isotope tests. Results showed that the lithology of the granite in the study area is mainly biotite granodiorite and biotite monzonitic granite. Reductions in both the K+ content in plagioclase and the K+ and Ti4+ contents in chlorite indicate that the alteration types within the study area are mainly clayization of feldspar minerals and chloritization of biotite. Biotite granodiorite and biotite monzonitic granite both have low δ18O values. The δ18O value of biotite granodiorite decreases with increase in the Loss on Ignition. The low-δ18O-value granodiorite due to an alteration by hydrothermal fluids transformed from glacier meltwater, groundwater, atmospheric precipitation, and magmatic water; whereas the monzonitic granite might be formed by the reinvasion of low-δ18O-value granodiorite formed in the early stage, which is remelted, assimilated, and rebalanced. The research findings provide a reference for similar research on altered granite at the northern foot of the Tianshan Mountains, and also lay a foundation for subsequent research on its physical/mechanical properties and engineering characteristics.

Characteristics of an underground stope channel supplied by atmospheric precipitation and its water disaster prevention in the karst mining areas of Guizhou

Atmospheric precipitation floods mining areas, which seriously affects the safe production of coal mines. However, research on the mechanism underlying precipitation supplying coal mines, particularly in karst landform areas, remains far from sufficient. Based on the collection of a large amount of geological and hydrogeological mining data and some data related to mine atmospheric precipitation and mine water inflow, the channels of atmospheric precipitation supplying mines in the main coal-producing areas of Guizhou, China, are systematically analysed and studied. They are divided into weathering zone fractures, mining fractures, water diversion faults, water diversion collapse columns and karst channels. Recharge channels have the characteristics of surface infiltration, pipeline flow and layered recharge, as well as self-healing after being filled by surface loess and other materials. The supply of atmospheric precipitation to the coal mine stope is seasonal. The mine water inflow in the rainy season is 1.2 ~ 12 times that in the dry season, with an average of 1.9 times. The supply has hysteresis. The lag time of surface infiltration, pipeline flow and layered flow is 2 ~ 4 days, within 24 h and more than 2 days, respectively. The recharge is affected by the burial depth of the coal seam and the characteristics of the combined upper roof slate. Among the mines affected by atmospheric precipitation and water disasters, some mines have carried out research on the comprehensive treatment of water disasters, implemented supplementary exploration projects such as surface hydrogeological drilling and geophysical exploration, or carried out hydrochemical research. Some mines have adopted water prevention and control projects, such as blocking ground water diversion cracks, constructing water diversion projects, adjusting the mining time of the working face, transforming the drainage system and improving the drainage capacity, to ensure the safe production of mines. This research achievement may provide a theoretical basis and practical experience for the prevention and control of atmospheric precipitation infiltration in coal mines in karst areas.

A proposed neural network model for obtaining precipitable water vapor

Abstract The atmospheric Precipitable water vapor (PWV) is a variable key for weather forecasting and climate change. It is a considerable component of the atmosphere, influencing numerous atmospheric processes, and having physical characteristics. It can be measured directly using radiosonde stations (RS), which are not always accessible and difficult to measure with acceptable spatial and time precision. This study uses the artificial neural network (ANN) application to propose a simple model based on RS data to estimate PWV from surface metrological data. Ten RS stations were used to develop the new model for eight and a half years. In addition, two and a half years of data were used to validate the developed model. The study period is based on the data accessible between 2010 and 2020. The new model needs to collect (vapor pressure, temperature, latitude, longitude, height, day of year, and relative humidity) as input parameters in ANN to predict the PWV. The ANN model validations were based on the root mean square (RMS), correlation coefficient (CC), and T-test. According to the results, the proposed ANN can accurately predict the PWV over Egypt. The results of the new ANN model and eight other empirical models (Saastamoinen, Askne and Nordius, Okulov et al., Maghrabi et al., Phokate., Falaiye et al. (A&B), Qian et al. and ERA 5) are compared in addition, the new PWV model can achieve the best performance with RMS of 0.21 mm. The new model can serve as a will be of practical utility with a high degree of precision in PWV estimation.

Precipitable water vapor retrievals using a ground-based infrared sky camera in subtropical South America

Abstract. Atmospheric precipitable water vapor (PWV) is a critical quantity in fast-changing weather processes. Current retrieval techniques lack the spatial and/or temporal resolution necessary for a full PWV characterization. Here we investigate a retrieval method using an all-sky ground-based camera comprising a 14-bit 644 × 512-pixel microbolometer sensor array. The radiometrically calibrated infrared downwelling spectral radiance, Lλ, was acquired at rates of up to 3 min−1. For the studied site (23.56∘ S, 46.74∘W; 786 m a.s.l.) and spectral interval, Lλ is sensitive to the PWV; the vertical distribution of humidity; and their temporal, spatial, or seasonal variations. By comparing measured and simulated Lλ, we show that the PWV can be retrieved from prior knowledge of the local humidity profile. This information can originate from radiosonde data or statistical analysis of past vertical humidity distributions. Comparison with sun photometer PWV retrievals, for stable atmospheric conditions, showed an agreement of the average PWV within 2.8 % and a precision of subsequent retrievals of 1.9 %. The PWV was also retrieved as a bi-dimensional array, allowing for the investigation of spatial inhomogeneities of humidity distribution. The method can be used for daytime or nighttime retrievals, under partly cloudy sky conditions. Potential applications include studies on convection initiation processes.

Study on Atmospheric Water Resource Variation Characteristics in China and Influencing Factors of Precipitation Efficiency of Hydrometeors

Understanding the spatial and temporal variation characteristics of atmospheric water resources in each region of China is essential for their exploitation. In this study, we focus on the variation in atmospheric precipitable water (PW), cloud parameters, cloud water resources (CWR), and precipitation efficiency of hydrometeors (PEh) as well as their possible influencing factors in each region of China in summer using ERA5 and MODIS data. The results showed that: (1) In the past 42 years, PW increased significantly in the northwest and Tibetan Plateau regions, and both cloud cover and total column cloud water content decreased significantly in northern China, except for medium-cloud cover which significantly increased in the Tibetan Plateau. (2) In the past 20 years, annual PEh was significantly higher, with clear interdecadal variation in most regions, whereas CWR decreased in northern China, the southwest, central region, and southeast, and increased in northeast and Tibetan Plateau. (3) PEh in each region was greatly influenced by precipitation (correlation coefficient 0.55 < R < 0.82 *, * = p < 0.05), having a significant positive correlation in the northeast with cloud water path, cloud optical thickness, and aerosol optical depth (0.44 * < R < 0.54 *), and a significant negative correlation in the central region with the cloud effective radius (R = −0.54 *).

Analysis and Evaluation of the Layered Precipitable Water Vapor Data from the FENGYUN-4A/AGRI over the Southeastern Tibetan Plateau

The Layered Precipitable Water Vapor (LPW) product derived from the Advanced Geosynchronous Radiation Imager (AGRI) onboard the first of the Chinese new generation geostationary satellite Fengyun-4A (FY-4A) has great significance for weather forecasting and climate monitoring of the Tibetan Plateau. To analysis and evaluation the reliability of the FY-4A/AGRI LPW, with respect to the complex terrain on the Southeastern Tibetan Plateau, the atmospheric precipitable water vapor values were calculated based on the radiosonde observations (RAOB TPW) of 11 radiosonde stations in the research area from 2019 to 2020, and a comparative analysis was performed with the FY-4A/AGRI LPW. The results indicated that: (1) FY-4A/AGRI LPW and RAOB TPW demonstrate excellent consistency in all of the vertical height layers, but the atmospheric precipitable water vapor was underestimated by FY-4A/AGRI LPW; (2) The mean values of FY-4A/AGRI LPW in various months were all lower than those of RAOB TPW. The low layer FY-4A/AGRI LPW was the most stable in precision from the dimension of months; and (3) The precision of FY-4A/AGRI LPW, and the deviation between FY-4A/AGRI LPW and RAOB TPW were related with RDLS. The evaluation results of the study demonstrated that FY-4A/AGRI LPW underestimated the total water vapor in the research area, but the Bias and RMSE values were relatively low. FY-4A/AGRI LPW had a relatively high precision, and the data from it had superior quality and stability in terms of time changes and spatial distribution. Therefore, the product can perfectly reflect the spatial and temporal variation of the atmospheric water vapor on the Southeastern Tibetan Plateau.

Performance of ERA5 data in retrieving precipitable water vapor over Hong Kong

When accurately retrieving atmospheric precipitable water vapor (PWV) using Global Positioning System (GPS) data, errors mainly originate from the effects of atmospheric weighted mean temperature (Tm) and ground meteorological data (e.g. surface pressure and temperature). This article assessed the accuracy of interpolated pressure and temperature from the European Centre for Medium-Range Weather Forecasts (ECMWF) fifth generation reanalysis dataset (ERA5), using actual meteorological data in the Hong Kong region from 2016 to 2020 as a reference.Radiosonde data were used to establish a linear equation (HKTm) between Tm and surface temperature (Ts), and a fitted equation between Tm, Ts, and water vapor pressure (HKTm-e). Then, these equations were evaluated using the Tm estimated by radiosonde with higher accuracy as a reference. On this basis, the PWV obtained from the measured meteorological data and BTm (GPS MET PWV) was compared with the PWV obtained from interpolated ERA5 meteorological data and HKTm-e (GPS ERA5 PWV), and the overall mean Bias and RMSE were −0.08 mm and 0.28 mm, respectively. In addition, PWV obtained from radiosonde data (RS PWV) was used to evaluate the accuracy of PWV obtained from ERA5 data (ERA5 PWV) and GPS ERA5 PWV. Then, the GPS ERA5 PWV was used to analyze the seasonal PWV variation and the effect of elevation on PWV in Hong Kong. The accuracy of ERA5 meteorological data is affected by the level of tropical cyclones in Hong Kong. Most of the differences are negative and the reason for the increased accuracy in temperature is explained based on the measured temperature and interpolated ERA5 temperature variations during all high-level tropical cyclones from 2016 to 2020. This article assessed the feasibility of using ERA5 data to replace the missing measured meteorological data during tropical cyclones. Based on the spatial variation of PWV as the tropical cyclone approaches Hong Kong, it is found that the spatial variation of PWV is related to the direction and location of the tropical cyclone.

The Effect of Natural and Anthropogenic Factors on the Seasonal Ecohydrological Dynamics of the Eastern Basin of the Hypersaline Sakskoe Lake, the Republic of Crimea

Crimean salt lakes have a high resource potential used in various types of human activity, i.e., balneology, chemical industry, and therapy; now, they are attractive tourist sites. A combination of biotic and abiotic factors creates specific conditions for the development and functioning of biota and the formation of unique ionic composition of brine and bottom sediments, which are used in balneology and the production of spa-products. Sakskoe Lake is among the largest coastal salt lakes of Crimea, located on the southwestern coast of the Black Sea. The effect of climate conditions and biota caused the formation of a specific ecosystem in the lake, which has a peculiar ionic composition of brine, changing within the year, and a brine shrimp population. The concentrations of cations and anions in the brine increased in summer because of active evaporation and decreased in winter and spring because of dilution of atmospheric precipitation and snowmelt water. The dynamics of the brine population also showed characteristic seasonal features: the life cycle begins in April, the maximal number of various life stages is recorded in May–June, and the end, in November–December. The artificial regulation of the water–salt regime of the water body through addition of seawater in summer contributed to maintaining optimal conditions, thus ensuring a high vital activity of the biota. The obtained data can reflect the seasonal dynamics of processes in the salt lake, governed by climatic, seasonal, and anthropogenic factors.

NOMINATION OF ATMOSPHERIC PRECIPITATION, PROCESSES AND CONCEPTS RELATED TO WATER FREEZING

Names of atmospheric precipitation resulting from water freezing were studied on the examples of eastern steppe dialects of the villages: Husarka, Bilmanka of the Zaporizhzhia region and the village of Temryuk of the Donetsk region.
 The article describes names for the first fall of snow in autumn, a snow-covered road, shovelful snow, snowy winter, names of deep, loose snow, blizzard, snowfall without wind, tent, snow slide, snowflakes, icicles, a layer of snow on tree bark large icicles, icicles, ice, frozen water, frost, small hail, the phenomenon of sliding (skating) on ice, freezing of snow, etc. The comments of residents contribute to a circle of representatives associated with water in the solid state. The study clarifies the specifics of some names and varieties of certain phenomena, etc.
 Commonly used lexemes or their phonetic, word-forming, morphological variants were found in the thematic vocabulary group: bu'rulka, za'met, kuchu'hura, ozhey'ledytsa, plys'ty, cha'lapaty, etc.; borrowings from contact languages: supolka (phonetical variant – su'pelka), so'sulka (phonetical variant – soa'sulka), suh'rob, mi'tel, constructions za'morzli 'vokna, narisu'vala zi'ma, etc. Certified nominations are mostly one- and two-component, less often descriptive constructions.
 Concerning the names that have counterparts in other dialects, parallels with the identical (metil ‘khurtovyna’, valyty ‘snizhyty’, peremót ‘peremet’, lod ‘lid’, etc.) and distinctive (suróvyi ‘raw, uncooked’, ‘stern, demanding of oneself and others’, peremét ‘a fishing tackle with many hooks, which was set across the stream’, draw ‘make folds in a skirt, dress; corrugation’, ‘invent, suggest something to oneself’, etc.) values have been found.

Quantitative Identification of Water Sources of Coalbed Methane Wells, Based on the Hydrogen and Oxygen Isotopes of Produced Water—A Case of the Zhijin Block, South China

The quantitative identification of water sources is an important prerequisite for objectively evaluating the degree of aquifer interference and predicting the production potential of coalbed methane (CBM) wells. However, this issue has not been solved yet, and water sources are far from being completely understood. Stable water isotopes are important carriers of water source information, which can be used to identify the water sources for CBM wells. Taking the Zhijin block in the Western Guizhou Province as an example, the produced water samples were collected from CBM wells. The relationships between the stable isotopic compositions of the produced water samples and the production data were quantitatively analyzed. The following main conclusions were obtained. (1) The δD and δ18O values of the produced water samples were between −73.37‰ and −27.56‰ (average −56.30‰) and between −11.04‰ and −5.93‰ (average −9.23‰), respectively. The water samples have D-drift characteristics, showing the dual properties of atmospheric precipitation genesis and water–rock interaction modification of the produced water. An index d was constructed to enable the quantitative characterization of the degree of D-drift of the produced water. (2) The stable isotopic compositions of produced water showed the control of the water sources on the CBM productivity. The probability of being susceptible to aquifer interference increased with the increasing span of the producing seam combination, reflected in the lowering δD and δ18O values and the decreasing gas productivity. (3) Three types of water, namely, static water, dynamic water, and mixed water, were identified. The characteristic values of the isotopic compositions of the static and dynamic water were determined. Accordingly, a quantitative identification method for the produced water sources was constructed, based on their stable isotopic compositions. The identification results have a clear correlation with the gas production, and the output of the static water contributes to the efficient CBM production. The method for the quantitative identification of the water sources proposed in this study, can help to improve the CBM development efficiency and optimize the drainage technology.

An Empirical Grid Model for Precipitable Water Vapor

Atmospheric precipitable water vapor (PWV) is a key variable for weather forecast and climate research. Various techniques (e.g., radiosondes, global navigation satellite system, satellite remote sensing and reanalysis products by data assimilation) can be used to measure (or retrieve) PWV. However, gathering PWV data with high spatial and temporal resolutions remains a challenge. In this study, we propose a new empirical PWV grid model (called ASV-PWV) using the zenith wet delay from the Askne model and improved by the spherical harmonic function and vertical correction. Our method is convenient and enables the user to gain PWV data with only four input parameters (e.g., the longitude and latitude, time, and atmospheric pressure of the desired position). Profiles of 20 radiosonde stations in Qinghai Tibet Plateau, China, along with the latest publicly available C-PWVC2 model are used to validate the local performance. The PWV data from ASV-PWV and C-PWVC2 is generally consistent with radiosonde (the average annual bias is −0.44 mm for ASV-PWV and −1.36 mm for C-PWVC2, the root mean square error (RMSE) is 3.44 mm for ASV-PWV and 2.51 mm for C-PWVC2, respectively). Our ASV-PWV performs better than C-PWVC2 in terms of seasonal characteristics. In general, a sound consistency exists between PWV values of ASV-PWV and the fifth generation of European Centre for Medium-Range Weather Forecasts Atmospheric Reanalysis (ERA5) (total 7381 grid points in 2020). The average annual bias and RMSE are −0.73 mm and 4.28 mm, respectively. ASV-PWV has a similar performance as ERA5 reanalysis products, indicating that ASV-PWV is a potentially alternative option for rapidly gaining PWV.

Pollution-Induced Changes in the Composition of Atmospheric Deposition and Soil Waters in Coniferous Forests at the Northern Tree Line

This study examines the dynamics of the composition of atmospheric precipitation and soil water in coniferous forests under the influence of atmospheric emissions from the Severonickel Copper–Nickel Smelter in Russia’s Murmansk region. We studied dwarf shrub-green moss spruce forests and lichen-shrub pine forests, the most common in the boreal zone. Our results showed a significant intra- (below and between the crowns) and inter-biogeocenotic (spruce and pine forests) variation in the composition of atmospheric precipitation and soil water in forests exposed to air pollution. The concentrations of main pollutants in atmospheric fallout and soil water are tens (sulfates) and hundreds (heavy metals) times higher than in the background areas and typically higher below the crowns. The long-term dynamics (between 1999 and 2020) of the composition of atmospheric fallout and soil water in coniferous forests in the background areas and defoliating forests demonstrates a significant increase in nickel concentrations in recent years. This may be due to an increase in nickel concentrations in aerosols propagating over considerable distances. In pollution-induced sparse forests, a trend was found toward a decrease in the concentration of pollutants, which may indicate a decrease in the fallout of pollutants in the composition of larger particles close to the smelter.

Analysis of Microtopography Atmospheric Precipitable Water Vapour over the Northeastern Margin of the Qinghai–Tibet Plateau

The Liupan Mountain (LPM) area is located on the northeast margin of the Qinghai–Tibet Plateau, which is the western part of the second ladder of China’s terrain. It is also an intersection area of two air currents, which are caused by the combined action of the Qinghai–Tibet Plateau, the middle and lower levels of the westerly belt and the edge of the monsoon area. LPM is one of the main air water vapour transport pathways in Northwest China as well as a main water conservation area for nearly ten million people. Research on atmospheric precipitable water vapour (PWV) variation characteristics in LPM is beneficial for understanding the mechanisms of orographic precipitation and improving the effects of weather modification. Based on the data from 10 Global Navigation Satellite System Meteorology (GNSS/MET) stations for 6 years and the data of automatic weather stations in the LPM, the temporal and spatial variation characteristics of PWV in the LPM were analysed, and the differences in PWV in the 24 h before and after precipitation were compared in this study. The results showed that the hourly, monthly and seasonal variations in PWV displayed obvious patterns. PWV increased rapidly 10 h ahead of precipitation, while it decreased rapidly within 10 h after precipitation, which was slower than that before precipitation. In terms of spatial distribution, PWV was larger in the south than in the north and larger in the east than in the west. Although the precipitation on the LPM peak was the highest in the whole LPM area, its PWV was always the lowest, indicating that the PWV was obviously affected by the air temperature. This showed that under the same water vapour condition, precipitation was more likely to form in the area with low temperature, and the precipitation was larger, which also provided a train of thought for improving the method of artificial precipitation enhancement by using the condensation catalyst.

Probing the Atmospheric Precipitable Water Vapor with SOFIA, Part III. Atlas of Seasonal Median PWV Maps from ERA5, Implications for FIFI-LS and in situ Comparison Between the ERA5 and MERRA-2 Atmospheric Re-analyses

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is an airborne observatory for far-infrared astronomy stationed at the Armstrong Flight Research Center (AFRC) in Palmdale, CA, USA. Although SOFIA flies at altitudes of ∼41,000 ft, any far-infrared observations from within the Earth’s atmosphere are nevertheless hampered by water vapor absorbing the astronomical signal. The primary atmospheric parameter governing absorption in the far-infrared is the total upward precipitable water vapor, PWV. In this paper we present global PWV maps derived from re-analyses from the European Centre for Medium-Range Weather Forecasts, ECMWF, with a geographical resolution of 0.°5, for flight altitudes ranging from 37,000 ft to 45,000 ft and each meteorological season. These maps were validated with FIFI-LS PWV measurements on board SOFIA and allow an investigation of the global morphology and seasonal dependence of the total upward PWV in the stratosphere. We additionally investigate the observing conditions, in terms of PWV, at various locations, especially around SOFIA’s home base, Palmdale, but also around sites in the southern hemisphere like Tahiti, Santiago de Chile (Chile), Buenos Aires (Argentina), and Christchurch (New Zealand). From the southern sites investigated Christchurch provides the best conditions in terms of PWV (and efficiency), Tahiti the worst. Using total power sky measurements with FIFI-LS we also derive a mean emissivity of the telescope (primary, secondary and tertiary mirror) of ϵ Tel = 20.5 ± 1.6% around the astronomically significant [C ii] emission line. We finally compare atmospheric re-analyses from GEOS (MERRA-2) and ECMWF (ERA5) to our FIFI-LS PWV measurements. Both re-analyses correlate linearly with our FIFI-LS PWV measurements from all flight altitudes but with different scaling factors. However, MERRA-2 correlates significantly less well than ERA5 especially for flight altitudes below 41,000 ft.

Лесопригодность экотопов Волго-Ахтубинской поймы для культур сосны

In the south of European Russia, the largest sand massifs are found in the zone of dry steppes and semi-deserts. Effective utilization of such lands requires creation of protective forest planting of drought-resistant coniferous species like Scots pine and Crimean pine. The productivity and longevity of such stands vary widely over the territory and depends on the presence of additional to atmospheric precipitation water supply and the root layer mineral supply. In this regard, sand massifs of steppificated river valleys composed of multiphase or single-phase polymineral rocks are of particular interest for afforestation. One of the most important objects of afforestation is the Northern (within the Volgograd region) highest and most drained part of the Volga-Akhtuba floodplain. Volga River damming by the Volga Hydroelectric Station (Volga GES) led to a restructuring of surface and ground water regimes, formation of new conditions of water and mineral nutrition and changes in other important factors of forest ecosystems in the area. The research aims at developing a classification of the Volga-Akhtuba floodplain ecotopes by water-mineral nutrition conditions, cultivation, expected productivity and longevity of pine plantings. We studied relationships of growth parameters of Pinus silvestris L. stands with soil-ground and hydrological conditions in different ecotopes of the large hilly and transitional floodplains after the Volga River damming by the Volga GES. Dynamics patterns of this relationship were revealed. It was found that in the northern part of the Volga-Akhtuba valley (approximately up to the Kapustin Yar – Kamenny Yar line) with increasing stratification, heavier granulometric composition of the root layer to sandy loam layer, lowering the surface level at a small distance from the drainage channel moisture supply and growth of Scots pine plantations improve, forest suitability of ecotopes increases. There is a risk of early decay and death of high-density pine forests in periods of low water and dry years on soils underlain by thick loams. Three groups of ecotope forest suitability were identified according to these indicators, as well as the conditions for the creation of forest plantations, productivity and longevity of plantings. The least favorable ecotopes are in the highlands of the hilly and transitional floodplains with minor soils of different composition on single-phase open-textured sands with deep (more than 4–5 m) groundwater table during low-water season. The most favorable are welldrained areas of the transitional floodplain with light soils on thick stratified predominantly sandy loam sediments, as well as on sands with close to the surface groundwater occurrence. Average ecotopes in terms of conditions are poorly drained areas of the transitional floodplain with minor sandy loam and loamy soils on deep loams.