Source Of Water Vapor Research Articles

Contributions of Multiple Water Vapor Sources to the Precipitation in Middle and Lower Reaches of Yangtze River Based on Precipitation Recycle Ratio

Global warming weakened the summer monsoon and increased the evaporation, leading to more contribution of local evaporation moisture to the local precipitation for the monsoon areas. However, the descriptions of the contribution of the local moisture to the total precipitation and its characteristics have not been known very well. In this paper, taking the middle and lower Reaches of the Yangtze River (MLRYR) as a case and using the precipitation recycling process model, we analyzed the characteristics of the contribution of the local moisture to the total precipitation and the possible reasons. The results show that: the seasonal difference in precipitation recycling rates is obvious, the precipitation recycling rates in spring and summer are small (18.30% and 19.30%), the maximum in autumn is 30.50%, and the precipitation recycling rates in all seasons except summer show a significant upward trend (about 1.70%/10a). Additionally, the water vapor input into MLRYR from four boundaries significantly reduced except for the eastern boundary, and the water vapor contribution from the South and East borders is in summer, and the water vapor contribution from the North and West borders is in autumn, winter and spring. We suggest that the model of the precipitation recycling rate is important to evaluate the contribution of different water vapor sources, and help to further improve the ability of river water prediction in flood season.

A Joint Impact on Water Vapor Transport over South China during the Pre-Rainy Season by ENSO and PDO

Based on precipitation data from 60 stations in South China (SC) and NCEP reanalysis data, the Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT_4.9) is used to analyze the difference of water vapor transport tracks, water vapor sources, and their precipitation contribution rate to frontal/monsoon precipitation, with four combinations of ENSO and PDO phase for a period of 53 years (1960–2012). The results show that: (1) For the frontal precipitation, in the Pacific Decadal Oscillation positive phase (PDO+), there is a great positive water vapor difference between ENSO+ (the positive ENSO phase) and ENSO− (the negative ENSO phase) over the tropical Indian Ocean (IO), the Bay of Bengal (BOB), the South China Sea (SCS) and the western Pacific (WP), the distribution of the difference is adjusted for PDO− (the negative PDO phase). For monsoon precipitation, when PDO and ENSO are in phase resonance, water vapor gathers over IO-BOB-SCS. (2) For the frontal precipitation, both PDO+ and PDO−, compare with ENSO+, more water vapor from SCS for ENSO−, but the southward water vapor transport anomaly over the western part of BOB-SCS-ocean east of the Philippines, which leads a decline in precipitation contribution rate of SCS water vapor. Both ENSO+ and ENSO−, compare with PDO−, more water vapor comes from IO-BOB for PDO+, but their precipitation contribution rates are lower. (3) For the summer monsoon precipitation, SCS and IO are important rain contributor sources. Regardless of the PDO phase, compared with ENSO+, there is more water vapor from the IO and WP for ENSO−, the easterly anomaly in the south of the stronger subtropical high brings more water vapor from WP to SC, the strong westerly anomalies in the IO-BOB-SCS increases IO water vapor transporting to SC, so water vapor precipitation contribution rates of IO and WP are higher. Both ENSO+ and ENSO−, compare with PDO−, more water vapor comes from SCS and EC for PDO+, but their precipitation contribution rates are lower. (4) The water vapor transport process of precipitation in PFS over SC is jointly affected by ENSO and PDO.

Isotopes-based characterization of precipitation compositions and atmospheric water vapor sources over typical Eurasian steppes in south mongolian Plateau

An inland river grassland basin is a fragile ecosystem, and precipitation is of great significance to its resilience. However, the knowledge of where precipitation-forming water vapor originated is not well understood, limiting the predictability of future precipitation provided climate change. The objective of this study was to characterize the hydrogen (δD) and oxygen (δ18O) isotopes and hydro-chemical compositions of precipitation as well as decipher atmospheric water vapor sources in a typical Eurasian steppe river basin. In this regard, this study collected 59 water samples from 44 storm events in 2019 and 2020. The samples were analyzed in our laboratory for ions, δD, and δ18O, which in turn were used to examine the stable isotopic features, hydro-chemical characteristics, and water vapor transport at different temporal scales by a backward trajectory model and correlation and redundancy analyses. The results showed negative δD and δ18O during the wet season with a trend of positive deuterium excess, indicating that precipitation effect was significant. In comparison with a linear model of global meteoric water levels, the local meteoric water lines had smaller slopes and intercepts, with a maximum slope in August and a minimum slope in July. In addition, HCO3− and Ca2+ were the primary hydro-chemical ions in precipitation. Ca2+ and Mg2+ were significantly correlated with HCO3− and Na+, indicating that they shared terrestrial and marine sources. NH4+ originated mainly from human activities and chemical reactions, whereas K+ originated primarily from continental and marine processes. Further, the atmospheric water vapor was mainly transported from the northeast, northwest, and southeast directions into the study basin, as affected by the westerly wind circulation, the East Asian summer monsoon, northeast anticyclone circulation, and local evapotranspiration. Moreover, the water vapor was from both onsite and offsite sources: over 40% from Eurasia, 10 to 25% from the Arctic Ocean, and 35 to 45% from the Pacific Ocean.

Characteristics of water vapor sources and precipitation contributions to drought and wet events on the Chinese Loess Plateau

In this paper, the standardized precipitation evapotranspiration index (SPEI) at the monthly scale was derived based on the ground observations to obtain different drought and wet events at the surface of the Loess Plateau in summer from 2000 to 2017. Using the National Centers for Environmental Prediction (NECP) Final Analysis (FNL) data for the same period, backward simulations with the FLEXPART model were performed to obtain the water vapor transport characteristics and potential evaporative sources corresponding to different dry and wet events. Finally, the contribution of water vapor sources to precipitation on the Loess Plateau was obtained. The results show that the primary sources of water vapor on the Loess Plateau during dry and wet summer events are concentrated in the Loess Plateau and the Yunnan-Kweichow Plateau regions and sporadically distributed in the Altay region of Xinjiang, as well as at the junction of China, Kazakhstan and Mongolia. The evaporation extent and intensity in northern Xinjiang and Mongolia increase when the surface experiences wet-normal-dry events. The local internal circulation on the Loess Plateau contributes to 31.3% and 36.8% of the water vapor in drought and wet events, respectively. Influenced by the westerly wind belt and southwest monsoon, the precipitation contributions of the Yunnan-Kweichow Plateau are 11.2% and 13.1%, respectively, and those of Mongolia are 14.6% and 11.9%, respectively. The water vapor contributions from the Arabian Sea and Bay of Bengal in the south are insignificant. The results aid in understanding the mechanisms of drought and wet events on the Loess Plateau.

Perturbations in stratospheric aerosol evolution due to the water-rich plume of the 2022 Hunga-Tonga eruption

The January 2022 Hunga Tonga-Hunga Ha’apai volcanic eruption injected a relatively small amount of sulfur dioxide, but significantly more water into the stratosphere than previously seen in the modern satellite record. Here we show that the large amount of water resulted in large perturbations to stratospheric aerosol evolution. Our climate model simulation reproduces the observed enhanced water vapor at pressure levels ~30 hPa for three months. Compared with a simulation without a water injection, this additional source of water vapor increases hydroxide, which halves the sulfur dioxide lifetime. Subsequent coagulation creates larger sulfate particles that double the stratospheric aerosol optical depth. A seasonal forecast of volcanic plume transport in the southern hemisphere indicates this eruption will greatly enhance the aerosol surface area and water vapor near the polar vortex until at least October 2022, suggesting that there will continue to be an impact of this eruption on the climate system.

Atmospheric recycling of agricultural evapotranspiration in the Tarim Basin

Precipitation recycling, defined as that precipitation in a region is partially contributed by evapotranspiration from the same region, is the interaction between terrestrial hydrology and atmospheric processes, and plays a crucial role in forming water resources. For agricultural lands, the evapotranspiration of irrigation water alters local climate by reprecipitation in surrounding regions, which can also be analyzed from the viewpoint of precipitation recycling. As the largest endorheic basin in China, the Tarim Basin has strong precipitation recycling contributed by the surrounding mountains, as well as large irrigation areas producing high-quality cotton, which makes it an appropriate study case for the recycling of irrigation water. In this paper, we calculate the water vapor sources of precipitation (WSoP) and the reprecipitation of evapotranspiration (RPoET) in the Tarim Basin by using the Water Accounting Model—Two Layers, analyze their spatial distributions, and find the moisture recycling ratio of the basin as 15.4%. We set up comparative scenarios of evapotranspiration increase by irrigation areas in different locations of the Tarim Basin, and study their difference in reprecipitation and moisture recycling. Results show that the evapotranspiration increase in different locations has a marginal reprecipitation ratio ranging from 8% to 24%, and further boosts the whole basin’s moisture recycling ratio by 0.11%–0.29%. Significant difference among the scenarios proves that the location of irrigation areas affects the reprecipitation of its evapotranspiration, and the optimized moisture recycling can benefit water resource and ecosystem conditions inside the basin. In summary, this work would be useful to provide a practical basis for irrigation planning by considering the land-atmosphere interaction.

An Evaluation of Precipitation in Dongting Lake Basin on CMIP5 Models

The rainfall in the Dongting Lake Basin influences tens of millions of people, and its long-term change remains uncertain. In this paper, 15 CMIP5 models with precipitation data for the time period of 2006–2019 for which reliable observations are available under the RCP4.5 scenario were evaluated for their applicability, and the models with better simulation results were selected for predicting the precipitation in the Dongting Lake Basin during the flood season (April–September) in the mid-21st century (2020–2049). The results of the study show that (i) most models behaved reasonably consistent with the observation in the Dongting Lake Basin, and predicted an upward trend for the future precipitation while the multi-model ensemble (MME) showed a relatively slow increasing trend of 0.8 mm/year; (ii) the future precipitation in Dongting Lake Basin presented a variation form of “peak–valley–peak–valley”, suggesting strong interannual and interdecadal variations; (iii) the interannual variability showed great agreement with large-scale circulation, implying that the rainfall is controlled by the circulation. The analysis of the wind fields at 200 hPa and 850 hPa in the peak and valley years showed that the characteristics of low-level convergence and high-level divergence were significantly stronger in the peak precipitation years than in the weak years; moreover, the teleconnection pattern of “+ − +” from Europe, the Ural Mountains, and East Asia was clearly manifested in the 500 hPa height field of the Dongting Lake Basin, which can influence the intensity of the trough ridge over East Asia and change the low-level water vapor convergence and divergence, thus affecting the source of water vapor in the Dongting Lake Basin.

Studies of meteorological elements in the River Basin Uruçuí Preto - PI, Brazil

The goal is to show the variability of meteorological elements in the catchment area of the river Uruçuí Preto - PI (BHRUP), aimed at contributing to sustainable development in the productive areas of agriculture, grain, fruit growing, fishing, laser and hydrology. Weather elements studied are temperature (maximum, minimum and average) air, and their maximum and minimum fluctuations, temperature range, relative humidity, wind (direction and intensity), total insolation, cloud cover, evaporation, evapotranspiration, rainfall. The data discussed are the series of 1960-1990, acquired by the Northeast Development Superintendency and the Company for Technical Assistance and Rural Extension of Piauí State. The maximum annual air temperature is 32.1 °C, annual minimum is 20 °C and the average annual temperature of 26.1 °C. We used climate classification according Köppen systems, which are distinguished two climatic types in the River basin Uruçuí Preto - PI, Aw, tropical hot and humid, with rains in summer and dry in winter; Bsh, hot semi-arid, with summer rains and dry winter. The variation of the temperature range is from 11.9 to 14.9 °C. The average relative humidity of the air is 47-79%, the average annual rainfall is 937.7 mm, it was observed that the annual march of relative humidity accompanies the annual distribution of rainfall because precipitation is the process of supply of natural sources of water vapor and moisture. The total area of Sunstroke BHRUP ranges between 2520 to 2750 hours. The annual evaporation ranges 100-226 mm and the annual evapotranspiration fluctuates between 1160-1600 mm, the intensity of the annual wind with the following highlights in the area of ​​small wind intensity in the far south and in the central and northern part of the southern region found if higher intensities, moderate winds in the northern sector of the central region and in every area of the northern region. The annual cloud cover ranges from 0.4 to 0.6 tenths.

Spatiotemporal Evolution of Urban Rain Islands in China under the Conditions of Urbanization and Climate Change

Precipitation is a critical factor affecting regional water cycles, water ecology, and socioeconomic development. Monthly precipitation, water vapor pressure, and temperature datasets from 613 meteorological stations across China were used to analyze the spatiotemporal evolution of urban rain island effects at the national scale during periods of slow (1960–1969) and accelerated (2010–2019) urbanization. The combined effects of artificial water dissipation and heat islands on urban precipitation were a key focus of this study. The results showed that rain island effects (0–31.6 mm/month) were primarily distributed along the southeast coast (dominated by the heat island effect) and northwest inland region (dominated by artificial water dissipation). During winter, the relative contribution of artificial water dissipation was higher in urban areas, and the rain island effect was more apparent than in the summer. Comparisons of precipitation prior to and following large-scale urbanization showed that precipitation and rain island intensity along the southeast coast and northwest inland region increased by 0–28 and 0–28.6 mm/month, respectively. These findings indicate that artificial water dissipation is an important water vapor source for urban precipitation, particularly during winter months.

Effects of Low-Frequency Oscillation at Different Latitudes on Summer Precipitation in Flood and Drought Years in Southern China

Based on the daily precipitation data from 753 meteorological stations provided by the National Meteorological Information Center (China) and the daily reanalysis data from NCEP/NCAR and ERA5 during the period from 1980 to 2020, the low-frequency (LF) precipitation characteristics of the typical summer flood and drought years in southern China and their relation to the LF atmospheric circulation at different latitudes are compared and analyzed, and extended-range forecasting signals are given. The results show that: (a) In both flood and drought years, summer precipitation in southern China is controlled by 10–20 day oscillation (quasi-biweekly oscillation, QBWO); (b) LF convection is active in southern China in both flood and drought years, but the convective center is southward in flood years, and the vertical meridional circulation is stronger. The key circulation systems of 500 hPa LF height field in flood and drought years include LF “two ridges and one trough” and LF “+”, “−”, “+” East Asia Pacific (EAP) teleconnection wave train in mid-high latitudes of Eurasia. However, the “two ridges and one trough” in flood years are more westward and meridional than in drought years, and the LF Subtropical High is stronger and more extensive, with more significant westward extension; (c) In flood (drought) years, there is northerly and then westerly (central westerly) dry-cold, northeasterly wet-cold, southwesterly (none), and southeasterly (including southerly across the equator) wet-warm water vapor channels. The sources of dry and wet cold air in flood (drought) years are located near Novaya Zemlya (the eastern West Siberian Plain), the Yellow Sea, and the Bohai Sea (Sea of Japan). Additionally, the sources of wet-warm water vapor include the Arabian Sea, the Bay of Bengal, the western Pacific Ocean, and the sea area of northeastern Australia (the western Pacific Ocean and the northern sea area of Australia); and (d) The LF predictive signals of outgoing longwave radiation (OLR) appear on −11 days, while the signals of the 500 hPa height field are on −9 days. There are both westward and eastward propagation predictive signals in flood years, and only westward spread signals in drought years.

Heavy precipitation events in northwestern China induced by northeastward plateau vortex: Two cases comparison

The plateau vortex is one of the dominant weather systems that modulate summer rainfall in northwestern China, a typical arid/semi-arid area worldwide. Two heavy rainfall cases in the summer of 2012 and 2013, accompanying the northeastward movement of plateau vortexes, are selected here. The role of plateau vortexes in these two cases is explored by diagnosing their moist potential vorticity, helicity, and convective clouds characteristics, using numerous data (ERA-Interim reanalysis, multi-sourced precipitation data, FY-2E satellite images). The plateau vortexes enhanced convective instability in the rainfall area by entraining upper-level dry and cold air, manifested as salient vertical gradients of moist potential vorticity and steep pseudo-equivalent potential temperature isolines. The rainfall occurred eastward relative to the vortex movement track and intensified on the left of cloud black body temperature (TBB) with larger gradients at the middle to late stages of the vortex life span. The generation of moisture helicity is dictated by the water vapor transportation, with the negative value concentrated in the water vapor-rich areas. Notably, the two cases differ in tracks, life spans, water vapor sources, and precipitation amounts, which may be attributed to large-scale circulation background, vertical vortex structure, and moisture condition.

Possible link between decadal variability in precipitation in the South China Sea and the North Atlantic Oscillation during the 20th century: A perspective from coral geochemical records

The South China Sea (SCS) is the major source of water vapor to China and East Asia. Modern observations, numerical simulations, and paleoclimate records suggest that on seasonal and annual timescales, variability in SCS precipitation is controlled mainly by the East Asian Monsoon and El Niño–Southern Oscillation (ENSO), respectively. Nevertheless, due to the lack of long-term observational records, our understanding of its decadal variability is limited. Because the understanding of decadal variability in SCS precipitation is fundamental in accurately predicting precipitation patterns in China and East Asia using climate models, it is necessary to obtain preinstrumental records of precipitation using climatic proxies in high resolution archives. We demonstrate the potential of coral Δδ18O, derived from Sr/Ca and δ18O measurements in the coral skeleton, as a proxy for precipitation in the SCS on different timescales. We then use this proxy to reconstruct decadal variability throughout the 20th century. The results suggest that the monsoon, Pacific Decadal Oscillation, ENSO, and Atlantic Multidecadal Oscillation are not significant forcings of decadal variability in precipitation over the SCS. In constrast, the North Atlantic Oscillation (NAO) might have modulated the number of tropical cyclones passing through the SCS and induced more (fewer) tropical cyclones and more (less) precipitation during its negative (positive) phases on decadal timescales during the past century. However, future numerical modeling studies are still required to improve our understanding of the underlying mechanism behind the relationship between the NAO and decadal variability in SCS precipitation.

Continental Water Vapor Dominantly Impacts Precipitation during the Snow Season on the Northeastern Tibetan Plateau

AbstractAtmospheric water vapor plays a key role in the water cycle, especially on the Tibetan Plateau, where precipitation is an invaluable contributor to water resources. To better understand which water vapor source areas influence precipitation on the northeastern Tibetan Plateau (NETP), we applied the flexible particle dispersion method (FLEXPART) to simulate water vapor trajectories and water vapor source contribution related to precipitation events during the snow season from 1979 to 2017 on the NETP. The results show that continental water vapor source areas contributed 92.33% of the water vapor to precipitation events on the NETP, which was obviously greater than the water vapor contribution from oceanic areas. One key continental water vapor source area, the Tibetan Plateau without the study area, contributed 66.13% of the water vapor to the precipitation, and central Asia supplied 8.69%, ranking second. Comparing the distributions of the water vapor contributions to extensive and regional precipitation events revealed that the only difference between extensive and regional precipitation events is in the magnitudes of the water vapor contributions, and the spatial distributions of the water vapor contributions are extremely similar. Central and southern China obviously supplied more water vapor to extensive precipitation events than to regional precipitation events. These results help us better understand the recent drastic precipitation changes on the NETP.Significance StatementWe sought to understand how water vapor influences precipitation over the northeastern Tibetan Plateau and which water vapor source areas play a key role in the water vapor supply. Therefore, we applied a numerical model to investigate the relationship between water vapor and precipitation from 1979 to 2017 during the snow season. Continental water vapor source areas contributed considerably more water vapor than oceanic water vapor source areas. The most important continental water vapor contributor was the Tibetan Plateau without the northeastern Tibetan Plateau area, and the second highest contributor was central Asia. Future work should focus on how water vapor impacts the precipitation changes in this wetter and warming area.

Atmospheric moisture sources of drought and wet events during 1979–2019 in the Three-River Source Region, Qinghai-Tibetan Plateau

The soil moisture observation data from the Qinghai-Tibetan Plateau permafrost and alpine wetland (PAW) monitoring network and from the National Center for Environmental Prediction (NCEP) Final Analysis (FNL) from 1989 to 2019 were adopted to drive the Lagrangian backward trajectory model to simulate the water vapour transportation paths and source regions to the three-river source region during dry and wet episodes. The results showed that the water vapour transport paths mainly came from the land and ocean in the west during the extreme drought episodes based on the standardized precipitation index (SPI), including the northern African continent, the eastern European plains, and the mid-latitudes of the Atlantic Ocean. The water vapour source regions were mainly concentrated in the Kashmir region, northeast India and southern Motuo on the Qinghai-Tibet Plateau. When the SPI indicated an extremely wet state, the transport mainly occurred to the east and south, including the Pacific Ocean and the South China Sea, where water vapour entered the mainland from East/South China, passed through the Yangtze River Basin, and finally reached the three-river source region from east or south of the Qinghai-Tibet Plateau, while the water vapour from the Indian Ocean and Arabian Sea passed through the Indian Peninsula and the Bay of Bengal and entered the three-river source region from the western and southern sides of the Qinghai-Tibet Plateau.

Revisiting the Effect of the Air-Water Interface of Ultrasonically Atomized Water Microdroplets on H2O2 Formation.

Studying chemical processes at the air-water interface is always challenging. A recent report claimed that H2O2 was formed spontaneously on the surface of condensed water microdroplets. However, a newer report concluded that the detected H2O2 in the previous report could originate in part from the water vapor source that involved ultrasonic atomization of liquid water. Here, this phenomenon is reinvestigated regarding the influence of ultrasonic cavitation, surface modification of droplets, and solutes in the bulk liquid on H2O2 production. When the droplet surfaces were modified by surfactants, H2O2 production did not change, whereas adding gases or inorganic compounds to the bulk solution caused significant changes in H2O2 production. These results confirm that H2O2 formation originates from cavitation in bulk solutions. It is concluded that the air-water interface of water microdroplets itself does not generate H2O2.

Asian Summer Monsoon Changes Inferred From a Stalagmite δ18O Record in Central China During the Last Glacial Period

The reconstruction of Asian summer monsoon (ASM) changes during the last glacial period is of great significance for better understanding monsoon dynamics. The phase relationship between the Indian summer monsoon (ISM) and East Asian summer monsoon (EASM) subsystems on different timescales is still unclear. The comparative analysis of speleothem records in the ISM region, EASM region, and central China helps to clarify the relationship between the ISM and EASM. Based on the well-dated isotope records of stalagmite DDH-B15 from the Didonghe (DDH) Cave in Hanzhong, Shaanxi, we reconstructed ASM changes during the past 34–13 thousand years before the present (kyr BP). The small average error (61 years) of 18 uranium-series ages enables a precise comparison of the stalagmite δ18O record with other well-dated records from the orbital to the millennial timescales. The δ18O signal of the DDH-B15 stalagmite is controlled by changes of the low latitude northern hemisphere summer insolation (NHSI) on the orbital timescale. It records cold Heinrich Stadial (HS) and Dansgaard–Oeschger (DO) cycles which are originated from the northern high latitude on the millennial time scale. The δ18O changes of stalagmites from the three regions are similar on the millennial and centennial timescales. But on the orbital-suborbital timescale, stalagmite δ18O changes during the last glacial cycle have different characteristics. The stalagmite δ18O values in eastern China became gradually negative, and the stalagmite δ18O values in the Indian monsoon domain showed a increasing trend, but the stalagmite δ18O values in Central China adopted an intermediate state between the EASM and ISM. Then we argued that the δ18O value of stalagmites in Central China is a mixed signal of the ISM and EASM, which indicates a change of the water vapor source as an important influence on the Chinese stalagmite δ18O record.

Monsoon Fringe Area Moisture Transportation Revealed by Water Stable Isotopes: A Lanzhou River Valley Case Study

Because of global warming, the water cycle has intensified and precipitation has changed, with monsoons evolving to become more complex, particularly in monsoon fringe areas. Therefore, it is important to use stable isotopes to trace moisture sources in monsoon fringe areas, such as semiarid areas. In this study, in situ measurements of water vapor isotopes were obtained in the monsoon fringe areas of Lanzhou (36.1° N, 103.7° E), between May and November 2019 with the aim of analyzing the stable isotope composition and atmospheric water vapor variation to improve our understanding of moisture transport. The following results were obtained: stable isotopic variation of atmospheric water vapor shows an alternation between west and southwest moisture with wind directions and sources of water vapor, with δ18O and δ2H varying from high to low. In the Lanzhou valley, water vapor isotopes show a distinct daily cycle of δ17O, δ18O, and δ2H and are consistent with temperature changes. Water vapor isotopes, particularly d-excess, are correlated with temperature and absolute humidity. With regard to the local atmospheric water vapor line (LAVL), we show that the slope and intercept of the LAVL are affected by sub-cloud secondary evaporation and topography.

Identifying water vapor sources of precipitation in forest and grassland in the north slope of the Tianshan Mountains, Central Asia

Identifying water vapor sources of precipitation in forest and grassland in the north slope of the Tianshan Mountains, Central Asia

Hydrochemistry and stable isotope indication of natural mineral water in Changbai Mountain, China

Study regionChangbai Mountain area, China. Study focusThe characteristics and process of water-rock interactions of natural mineral water are revealed using hydrochemical and isotopic data. New hydrological insightsThe results confirm rock weathering plays a leading role in the mechanism of chemical composition of mineral water, which is controlled by lithology and tectonic environment within the region. Mineral water chemistry is mainly controlled by dissolution/precipitation of feldspar, pyroxene and olivine. The hydrolysis of primary silicate minerals may provide solutes for CO2 and metasilicate. Deep underground circulation and shallow soil leaching promotes the formation compound mineral water. Affected by temperature and water vapor sources, slope of Local Meteoric Water Line is less than Global Meteoric Water Line. Compared with mineral water, surface water is more affected by evaporation and stable isotopes of it is more enrich. There is a certain delay in precipitation recharge according to isotope characteristics. The average recharge ratio of mineral water to surface water is 60%, which has a great impact on the amount of surface water resources. These results can provide a reference for the establishment of genetic model and sustainable utilization of natural mineral water with high ecological value.

Impact of Interaction between Metropolitan Area and Shallow Lake on Daily Extreme Precipitation over Eastern China

Both cities and lakes have significant impacts on regional precipitation. With global warming, extreme precipitation events in Eastern China have increased significantly, and the single/joint influences of metropolises and lakes on extreme precipitation still need to be quantitatively evaluated. To reveal the impact of the single/joint influences of metropolises and lakes on the shear line torrential rain process, the Suzhou-Wuxi-Changzhou Metropolitan Area (SXCMA) and Lake Taihu in Eastern China were selected as the study area. Utilizing a WRF model, comparative studies of sensitivity simulations were conducted for the two typical extreme precipitation events caused by the low-level shear line (LLSL) on 27 June 2015 (EP627) and 25 September 2017 (EP925). Both results show that the existence of Lake Taihu and SXCMA will increase precipitation in the study area. SXCMA has a more obvious effect on enhancing precipitation, which is about twice the effect of Lake Taihu. SXCMA mainly strengthens the intensity and movement of the surface convergence line (SCL) in the study area and indirectly affects the shift of the LLSL, which finally affects the intensity and location of precipitation. Lake Taihu affects the intensity and movement of SCL, triggering ground vertical convections due to lower surface roughness, and acts as a land-lake breeze and water vapor source, which will affect the distribution and intensity of precipitation.