Seasonal constraint of dynamic water temperature on riverine dissolved inorganic nitrogen transport in land surface modeling

水体温度变化对河流可溶性无机氮(DIN)输送有着强烈控制作用.然而,在全球尺度上河流DIN输送量对水温度变化的响应尚不清楚.因此,本文基于陆面过程模式,耦合河流水温估算和DIN传输方案,设定有,无动态水温情景,对比研究陆面模拟中水温变化对河流DIN通量变化的影响.结果表明:在考虑水温动态变化后,在30°N和30°S之间, DIN通量年振幅减小5%–25%.在中国东部地区,水温动态变化使河流DIN通量在夏季减少1%–3%,在冬季增加1%–5%,对DIN通量具有明显的季节性约束作用,表明动态水温的表达在河流DIN输送模拟中的重要性.

Comparative Study of the Physicochemical Quality of the Waters of the Méné River (Sassandra Watershed, Ivory Coast) in the Dry Season and in the Rainy Season

The study carried out on the waters of the Méné River led to an overall assessment of its water quality during the dry season and the rainy season. The analysis focused on eight (8) water samples taken from the river during a period of dry season (January-February) and a period of rainy season (June and September). The various physicochemical parameters were measured according to Afnor standardized methods. The readings of temperature, turbidity, pH and conductivity made it possible to account for the disturbances occurring in water quality. A temporal variation correlated with the seasons (dry or rainy) is noted. Turbidity depends on the concentration of suspended solids (SS) in the water and drained particles and therefore on the seasons. Just like the temperature, the conductivity changes with the season. The waters of the Méné River are generally acidic. The results obtained show that there is a low level of pollution by chlorides, phosphates, nitrites and nitrates. A slight pollution of the waters of Méné in organic matter (chemical oxygen demand values are less than 25 mg∙L−1 during dry season and 32.33 ± 4.73 mg∙L−1 during rainy season) was observed. The concentrations of metallic trace elements such as iron, manganese and aluminum indicate significant pollution of these waters by these elements. Overall, the waters of the Méné River are of satisfactory quality because all the physicochemical parameters analyzed have values below standards during the dry season as well as during the rainy season with the exception of COD and a few metallic trace elements.

Seasonal Difference of the Spatio-Temporal Variation of Precipitable Water Vapor in China

This study analyzes the spatial and temporal distribution characteristics of seasonal precipitable water vapor (PWV) in China between 1979 and 2008. To achieve this, the observed temperature dew point difference and atmospheric pressure at various altitudes of 102 radiosonde stations were utilized. The analysis involved calculating and examining the PWV variations across the different seasons in the study period. The results are illustrated as follows: 1) The annual mean and seasonal mean PWV over China is characterized by decreasing from southeast to northwest. The PWV has obvious seasonal features. It is the least in winter, which is mainly affected by latitude and altitude, and the most in summer, which is mainly affected by the monsoon. It is the medium in spring and autumn, with more in autumn than in spring. 2) The spatial distribution pattern of four seasonal PWV is approximately opposite to its variation coefficient distribution pattern, that is, the monsoon (non-monsoon) areas with more (less) PWV have a smaller (larger) variation amplitude. 3) The distribution pattern of four seasonal PWV shows a consistent distribution pattern in the whole region and the winter characteristics are the most significant. The abnormal variation of PWV shows consistent interdecadal oscillation, and it exhibits an obvious phase transition around 2002 when the PWV has an increasing shift in winter, spring, and summer, while it is more complicated in autumn.

Principles of Technology for Bottling Medicinal Mineral Waters of Sairme Using the Example of Source №3a

Sairme mineral water, one of the famous mineral waters in Georgia, is renowned for its exceptional healing properties. The distinctiveness and therapeutic benefits of the naturally sourced mineral water, known as “Sairme”, stem from its rich array of microelements, notably including iron and manganese. Since 1948, the bottling of Sairme mineral water has been a prominent activity. Named after the Sairme deposit, this mineral water is packaged in various formats to cater to diverse consumer preferences. The bottling process involves transporting the mineral water from wells to the bottling plant through pipelines. Prior to bottling, the mineral water undergoes meticulous processing stages in adherence to current Georgian and international regulations. This process ensures that the concentration of trace elements in the bottled water is minimized, maintaining its purity and quality. Given the importance of preserving the microelements present in bottled mineral water, our research is dedicated to optimizing the technological process. Our objective is to safeguard the valuable microelements while ensuring the highest standards of quality and safety in the final product.

Seasonal variation of water transport through the Karimata Strait

Four trawl-resistant bottom mounts, with acoustic Doppler current profilers(ADCPs) embedded, were deployed in the Karimata Strait from November 2008 to June 2015 as part of the South China Sea-Indonesian Seas Transport/Exchange and Impact on Seasonal Fish Migration(SITE) Program, to estimate the volume and property transport between the South China Sea and Indonesian seas via the strait. The observed current data reveal that the volume transport through the Karimata Strait exhibits significant seasonal variation. The winteraveraged(from December to February) transport is –1.99 Sv(1 Sv=1×10~6 m^3/s), while in the boreal summer(from June to August), the average transport is 0.69 Sv. Moreover, the average transport from January 2009 to December2014 is –0.74 Sv(the positive/negative value indicates northward/southward transport). May and September are the transition period. In May, the currents in the Karimata Strait turn northward, consistent with the local monsoon. In September, the southeasterly trade wind is still present over the strait, driving surface water northward, whereas the bottom flow reverses direction, possibly because of the pressure gradient across the strait from north to south.

The study on seasonal characteristics of water masses in the western East China Sea shelf area

On the basis of the CTD data and the modeling results in the winter and summer of 2009, the seasonal characteristics of the water masses in the western East China Sea shelf area were analyzed using a cluster analysis method. The results show that the distributions and temperature-salinity characteristics of the water masses in the study area are of distinct seasonal difference. In the western East China Sea shelf area, there are three water masses during winter, i.e., continental coastal water（CCW）, Taiwan Warm Current surface water（TWCSW） and Yellow Sea mixing water（YSMW）, but four ones during summer, i.e., the CCW, the TWCSW, Taiwan Warm Current deep water（TWCDW） and the YSMW. Of all, the CCW, the TWCSW and the TWCDW are all dominant water masses. The CCW, primarily characterized by a low salinity, has lower temperature, higher salinity and smaller spatial extent in winter than in summer. The TWCSW is warmer, fresher and smaller in summer than in winter, and it originates mostly from the Kuroshio surface water（KSW） northeast of Taiwan, China and less from the Taiwan Strait water during winter, but it consists of the strait water and the KSW during summer. The TWCDW is characterized by a low temperature and a high salinity, and originates completely in the Kuroshio subsurface water northeast of Taiwan.

The numerical investigation of seasonal variation of the cold water mass in the Beibu Gulf and its mechanisms

A wave-tide-circulation coupled model based on the Princeton Ocean Model is established to explore the seasonal variation of the cold water mass in the Beibu Gulf and its mechanisms. The results show that the cold water mass starts forming in March, reaches the maximum strength during June and July, and fades away since October. Strong mixing in winter transports the cold water from sea surface to bottom. The cold water mass remains in the bottom layer as the thermocline strengthens during spring, except for the shallow water where the themocline is broken by strong tidal mixing, which gradually separate the cold water mass from its surrounding warm water. Further analysis on the ocean current and stream function confirms that the cold water mass in the Beibu Gulf is locally developed, with an anticlockwise circulation caused by a strong temperature gradient. Sensitivity experiments reveal that the cold water mass is controlled by the sea surface heat flux, while the terrain and tidal mixing also play important roles.

Water Security-based Hydrological Regime Assessment Method for Lakes with Extreme Seasonal Water Level Fluctuations：A Case Study of Poyang Lake,China

Extreme seasonal water level fluctuations characterize natural floodplain lakes in monsoon regions, which are crucial for ensuring lake water security, including flood prevention water supply and health of aquatic ecosystem. In order to achieve this goal, we established a hydrological regime assessment method based on a set of hydrological indicators for lakes with heavy seasonal water level fluctuations. The results suggest that time-sensitive hydrological indicators and specific time scales for various water security aspects must be considered. We discovered that it is more practical and meaningful to combine the water level classification derived from statistical analyses with characteristic hydrological values linked to water security. The case study of Poyang Lake results show that there are no discernable trends of Poyang Lake water regime status over the last 35 years, and the two periods of poor status are in accordance with climate variation in the lake basin area. Scholars and policy makers should focus on both floods and droughts, which are the main water security problems for Poyang Lake. It is hoped that this multi-scale and multi-element hydrological regime assessment method will provide new guidelines and methods for other international scholars of river and lake water assessment.

Analysis on the daily courses of water potential of nine woody species from Cerrado vegetation during wet season

The water potential (Ψ) daily courses of 9 woody species from Cerrado vegetation in different weather conditions during wet season were observed and analyzed. The adjusting strategies of 9 species could be divided into 3 groups according to Cluster Analysis and based on the data observed on the January 18, March 20 and April 6. The Ψ values of the first group, which included 2 species, were maintained at the higher level consistently. The Ψ values of the second group, which included 5 species, were intermediate level. The Ψ values of the third group, which included 2 species, were kept in the lower level. The Ψ values of all species always kept pace with the weather condition, especially water condition. During the clear day only one Ψ value peak for all species occurred at midday (12∶30–13∶30). When the overcast or raining occurred for a short period, the fluctuation of Ψ values would appear after about 15–30 min responding to the change of weather condition. Even in the same group under the same external circumstance, there was a clear variation of the leaf Ψ values among different species, which showed that the strategy diversity for plant to balance water relation. From January to April, the Ψ values of 9 species reduced in response to the drought condition. The species with the lower values of water saturation deficiency at turgid loss point (W sdtlp) the osmotic potential at saturation (πsat), the osmotic potential at turgid lose point (πtip) or lower predawn water potential (Ψpd) usually had the lower Ψ values at midday. The mechanism of water balance controlled by many systems has been assumed.

Succession and seasonal variation in epilithic biofilms on artificial reefs in culture waters of the sea cucumber Apostichopus japonicus

Periphytic biofilms in aquaculture waters are thought to improve water quality, provide an additional food source, and improve the survival and growth of some reared animals. In the AsiaPacific region, particularly in China, artificial reefs are commonly used in the commercial farming of sea cucumbers. However, few studies have examined the epilithic biofilms on the artificial reefs. To gain a better understanding of the succession of epilithic biofilms and their ecological processes in sea cucumber culture waters, two experiments were conducted in culture waters of the sea cucumber Apostichopus japonicus in Rongcheng, China, using artificial test panels. On the test panels of succession experiment, more than 67 species were identified in the biofilms. On the test panels of seasonal variation experiment, more than 46 species were recorded in the biofilms. In both experiments, communities of epilithic biofilms were dominated by diatoms, green algae and the annelid Spirorbis sp. In the initial colonization, the dominant diatoms were Cocconeis sp., Amphora spp. and Nitzschia closterium in June, which were succeeded by species of Navicula, Cocconeis and Nitzschia(July to September), and then by Licmophora abbreviata, Nitzschia closterium and Synedra spp. in the following months. A diatom bloom in the autumn and filamentous green algae burst in the summer were also observed. Ecological indices well annotated the succession and seasonal changes in epilithic communities. Multidimensional scaling(MDS) analysis found significant differences in diatom community composition among months and seasons. Fast growth of biofilms was observed in the summer and autumn, whereas the biomass of summer biofilms was largely made up of filamentous green algae. Present results show that the components of epilithic biofilms are mostly optimal foods of A. japonicus, suggesting that biofilms on artificial reefs may contribute important nutritional sources for sea cucumbers during their growth seasons. Future works should include quantitative determination of the contribution of epilithic biofilms to the diet of A. japonicus, potential roles of epilithic biofilms in regulating the water quality of sea cucumber ponds, and the regulation of epilithic biofilms in sea cucumber culture ponds.

Water discharge changes of the Changjiang River downstream Datong during dry season

Based on hydrometric data and extensive investigations on water-extracting projects, this paper presents a preliminary study on water discharge changes between Datong and Xuliujing during dry season. The natural hydrological processes and human factors that influence the water discharge are analyzed with the help of GIS method. The investigations indicate that the water-extracting projects downstream from Datong to Xuliujing had amounted to 64 in number by the end of 2000, with a water-extracting capacity up to 4,626 m 3 /s averaged in a tidal cycle. The water extraction from the Changjiang River has become the most important factor influencing the water discharge downstream Datong during dry season. The potential magnitude in water discharge changes are estimated based on historical records of water extraction and a water balance model. The computational results were calibrated with the actual data. The future trend in changes of water discharge into the sea during dry season was discussed by taking into consideration of newly built hydro-engineering projects. The water extraction downstream Datong in dry season before 2000 had a great influence on discharges into the sea in the extremely dry year like 1978-1979. It produced a net decrease of more than 490 m 3 /s in monthly mean discharges from the Changjiang into the sea. It is expected that the water extraction will continually increase in the coming decades, especially in dry years, when the net decrease in monthly mean water discharge will increase to more than 1000 m 3 /s and will give a far-reaching effect on the changes of water discharge from the Changjiang into the sea.

Discussion on applying an analytical method to optimize the anti-freeze design parameters for underground water pipelines in seasonally frozen areas

Adopting the quasi-three-dimensional （Quasi-3D） numerical method to optimize the anti-freeze design parameters of an underground pipeline usually involves heavy numerical calculations. Here, the fitting formulae between the safe con-veyance distance （SCD） of a water pipeline and six influencing factors are established based on the lowest water temper-ature （LWT） along the pipeline axis direction. With reference to the current widely used anti-freeze design approaches for underground pipelines in seasonally frozen areas, this paper first analyzes the feasibility of applying the maximum frozen penetration （MFP） instead of the mean annual ground surface temperature （MAGST） and soil water content （SWC） to calculate the SCD. The results show that the SCD depends on the buried depth if the MFP is fixed and the variation of the MAGST and SWC combination does not significantly change the SCD. A comprehensive formula for the SCD is estab-lished based on the relationships between the SCD and several primary influencing factors and the interaction among them. This formula involves five easy-to-access parameters： the MFP, buried depth, pipeline diameter, flow velocity, and inlet water temperature. A comparison between the analytical method and the numerical results based on the Quasi-3D method indicates that the two methods are in good agreement overall. The analytic method can be used to optimize the anti-freeze design parameters of underground water pipelines in seasonally frozen areas under the condition of a 1.5 safety coefficient.

Seasonal variation and formation mechanism of the South China Sea warm water

The South China Sea warm water (SCSWW) is identified as the warm water body withtemperature no less than 28*. There are three stages in the seasonal variation of the SCSWW. The SCSWW expands rapidly and deepens quickly in the developing stage. The warm water thickness decreases near the coast of Vietnam and increases near Palawan Island in the steady stage. The SCSWW flinches southward while its thickness off Palawan Island remains no less than 50 m in the flinching stage. The maximum thickness of the SCSWW is always located near the southeastern SCS. The seasonal variation of the SCSWW has a close relationship with seasonal variation of the thermocline. According to the analysis of the numerical experiment results from the Princeton Ocean Model (POM), the mechanism of the seasonal variation of the SCSWW can be interpreted as: (1) in the developing stage, the rapidly expanding and thickening feature of the SCSWW is mainly due to buoyancy flux effect (67% contribution). The weak wind and anticyclonic wind stress curl (22% contribution) present an environment which facilitates the accumulation of warm water; (2) in the steady stage, the decrease feature near the Vietnam coast and increase eature in southeast of the SCSWW thickness are mainly caused by wind stress (70% contribution); (3) in the flinching stage, the thickness reduction of the SCSWW is mainly due to upwelling and enhanced turbulent mixing caused by wind stress (accounts for 60%).

Spatial and seasonal pattern of macrozoobenthic assemblages and the congruence in water quality bioassessment using different taxa in artificial Mingzhu Lake in Shanghai

The spatial and seasonal pattern of macrozoobenthic structure and its relationship with environmental factors were studied from July 2006 to April 2008 in Mingzhu Lake,Chongming Island,Shanghai at the Changjiang River mouth.The congruences in water quality bioassessment based on diversity and biotic indices and using different taxonomic categories were also explored to find the best assessment method of water quality for the lake.All major structural characteristics of macrozoobenthic community,including species composition,abundance,biomass and four biomass-based diversity indices(Shannon's diversity,Simpson's diversity,Pielou's evenness and Simpson's evenness index) fluctuated significantly in season but in space.The above four abundance-based diversity indices plus abundance-based Margalef's richness index did not display significant spatial variations;and significant seasonal differences were found in three indices only.Water temperature was the key environmental factor responsible for macrozoobenthic spatio-temporal distribution patterns.Water quality assessed by Shannon's index(H_a') and biological pollution index(BPI) rather than the other four biotic indices were consistent with those by trophic state index(TSI).Results from chironomids and oligochaetes did not always agree to those from the whole community when H_a' or Hilsenhoff biotic index was applied to bioassessment.Therefore,combining multiple indices and avoiding a single taxonomic category to assess water quality are strongly recommended and in Mingzhu Lake using a mixture of H_a' and BPI will ensure the most effective investigation of water quality.Our results also show that the main structural characteristics of macrozoobenthic communities in the small lake may display consistent spatial patterns.

Seasonal Variation in Physicochemical Properties of Groundwater, a Case Study of Kamiti-Marengeta Subcatchment Kiambu, Kenya

The seasonal variation and quality status of groundwater systems of Kamiti-Marengeta sub-catchment were evaluated through analysis of boreholes and 17 shallow wells water samples in May 2016 and September 2017. Consequently, the results were compared against the Kenya Bureau of Standards (KEBS) and World Health Organization (WHO) guidelines for drinking water purposes, and its suitability for drinking was established. The results showed that turbidity, calcium, potassium, iron, and fluoride levels in some of the boreholes and pH, calcium, sodium, and iron levels in some shallow wells exceeded the KEBS and WHO standards for drinking water quality. Turbidity, dissolved oxygen, and total hardness significantly varied across the regions of the study, and one-way ANOVA (P < 0.05) indicated a significant difference in the mean concentration of electrical conductivity, turbidity, total hardness, calcium, and iron in boreholes and in all parameters in shallow wells except for magnesium during the two seasons. The findings of this study provide baseline information on the quality of the groundwater systems of the area. It also contributes to knowledge on seasonal variation of groundwater quality of volcanic aquifers like the Nairobi Aquifer System (NAS) which is important for water quality monitoring.

Characteristics of Water Type Distribution and Seasonal Variations in the Southern East China Sea

By using the data of Summer and Winter 1987, Spring and Autumn 1988 obtained by the R/V " Shijian" during the China-Japan Joint Research Program on Kuroshio, the paper makes an analysis and research on the water type distribution and its variations in the studied sea area. Trie results of which are mainly as follows: (1) The Class IV mixing water whose property is similar to that of the continental coastal water is located in the northeast sea area, along the coast of the continent in autumn and winter while extending to the open sea in spring and summer. (2) The boundary between the Kuroshio water and the shelf mixing water (called the left boundary of the Kroshio water) is approximately located in between the 100m and 200m isobaths in various seasons and various layers, and mostly near the 200m isobath. In the sea area northeast of Taiwan, the Kuroshio water is to the west most in spring and then in winter. In summer, it is to the east most while, in autumn, it is in between its positions in summer

Changes in quality of groundwater with seasonal fluctuations: an example from Ghor Safi area, southern Dead Sea coastal aquifers, Jordan

The demand for water resources in the area south of the Dead Sea due to continued development, especially at the Arab Potash Company （APC） for production and domestic purposes necessitates that water quality in the area be monitored and evaluated based on the local geology and hydrogeology. The objective of this paper is to monitor seasonal fluctuations of groundwater and to determine how fluctuation in the water levels will affect the groundwater quality. Groundwater levels were found to be influenced by rainfall and pumping of water from the wells for domestic and industrial use. Twenty water samples were collected from different wells and analyzed for major chemical constituents both in pre- and post-seasons to determine the quality variation. Chemical constituents are significantly increased after post-season recharge. According to the overall assessment of the area, water quality was found to be useful for drinking, irrigation and industry.

Profile distribution and seasonal dynamics of water-extractable carbohydrate in soils under mixed broad-leaved Korean pine forest on Changbai Mountain

Carbohydrate represents an important part of the soil labile organic carbon pool. Water soluble carbohydrate drives the C cycle in forest soil by affecting microbial activity and hot water extractable car- bohydrate is thought related to soil carbon sequestration due to the asso- ciation with soil aggregation. In a temperate forest region of northeast China, Changbai Mountain, we investigated the abundance, spatial dis- tribution, and seasonal dynamics of cool and hot-water extractable car- bohydrate in soils under mixed broad-leaved Korean pine forest. The concentrations of cool-water extractable carbohydrate （CWECH） in three soil layers （0-5, 5-10, 10-20 cm） ranged from 4.1 to 193.3 g.kg-1 dry soil, decreasing rapidly with soil depth. On an annual average, the CWECH concentrations in soils at depths of 5-10 and 10-20 cm were 54.2% and 24.0%, respectively, of that in the 0-5 cm soil layer. CWECH showed distinct seasonal dynamics with the highest concentrations in early spring, lowest in summer, and increasing concentrations in autumn. Hot-water extractable carbohydrate （HWECH） concentrations in three soil layers ranged from 121.4 to 2026.2 g.kgq dry soil, which were about one order of magnitude higher than CWECH. The abundance of HWECH was even more profile-dependent than CWECH, and decreased more rapidly with soil depth. On an annual average, the HWECH concentration in soils 10-20 cm deep was about one order of magnitude lower than that in the top 0-5 cm soil. The seasonality of HWECH roughly tracked that of CWECH but with seasonal fluctuations of smaller amplitude. The car- bohydrate concentrations in cool/hot water extracts of soil were positively correlated with UV254 and UV2s0 of the same solution, which has implications for predicting the leaching loss of water soluble organic carbon.

Seasonal and Interannual Variations of Upper Tropospheric Water Vapor Band Brightness Temperature over the Global Monsoon Regions

The upper-troposphere water vapor (UTWV) band brightness temperature (BT) dataset derived from the High-resolution Infrared Radiation Sounder (HIRS) channel 12 of the National Oceanic and Atmospheric Administration (NOAA) polar satellites from 1979 to 1995 is used to analyze the seasonal and interannual variations for the global monsoon regions. Results show that (i) there are three major regions where the UTWV band BT varies significantly with season, i.e., South Asia, the western coastal South-North America tropical region and the low-latitude African region; (ii) UTWV band BT clearly reveals the water vapor temporal/spatial features as well as the atmospheric circulation structure over the low-latitude during the monsoon onset; and (iii) there is a remarkable relationship between the interannual variation of the UTWV band BT over the monsoon regions and the sea surface temperature anomaly in the eastern equatorial Pacific.

Numerical Study on Seasonal Transportation of the Suspended Sediments in the Modern Yellow River Mouth Effected by the Artificial Water and Sediment Regulation

Since 2002, an artificial water and sediment regulation(AWSR) has been carried out, which largely reduced water and sediment discharged from the Yellow River into the Bohai Sea. Although the sediment transport in the Yellow River Mouth(YRM) has been observed and modeled intensively since AWSR, but preferentially for the non-storm conditions. In this study, a three-dimensional current-wave-sediment coupled model, DHI-MIKE numerical model, was used to examine the seasonal suspended-sediment transport in the YRM after the AWSR. Results show that the seasonal distribution of suspended-sediments in the YRM is dominated by wind and wave rather than river input. The major transport pathway of suspended-sediments is from the western Laizhou Bay to the Bohai Strait during the winter monsoon, especially in storm events. In addition, about 66% of the river sediments deposit within 30 km of the YRM, which is smaller than previous estimations. It suggests that the YRM has been eroded in recent decades.