Interdecadal variability of summer precipitation in the Three River Source Region: Influences of SST and zonal shifts of the East Asian subtropical westerly jet

Summer precipitation in the Three Rivers Source Region(TRSR)of China is vital for the headwaters of the Yellow,Yangtze,and Lancang rivers and exhibits significant interdecadal variability.This study investigates the influence of the East Asian westerly jet(EAWJ)on TRSR rainfall.A strong correlation is found between TRSR summer precipitation and the Jet Zonal Position Index(JZPI)of the EAWJ from 1961 to 2019(R=0.619,p<0.01).During periods when a positive JZPI indicates a westward shift in the EAWJ,enhanced water vapor anomalies,warmer air,and low-level convergence anomalies contribute to increased TRSR summer precipitation.Using empirical orthogonal function and regression analyses,this research identifies the influence of large-scale circulation anomalies associated with the Atlantic–Eurasian teleconnection(AEA)from the North Atlantic(NA).The interdecadal variability between the NA and central tropical Pacific(CTP)significantly affects TRSR precipitation.This influence is mediated through the AEA via a Rossby wave train extending eastward along the EAWJ,and another south of 45°N.Moreover,the NA–CTP Opposite Phase Index(OPI),which quantifies the difference between the summer mean sea surface temperatures of the NA and the CTP,is identified as a critical factor in modulating the strength of this teleconnection and influencing the zonal position of the EAWJ.

Analysis on Strategic Future of Application of Agricultural Ecological Source in Control on Agricultural Nonpoint Source Pollution in Xi River Area in Guangxi

Non-point source pollution has become a hot issue on aquatic ecological environment at home and abroad. The research analyzed the challenges confronted by Xi River and proposed to construct agricultural ecological source in middle and upper reaches of the Xi River from the perspectives of scientific layout, legal construction, routine monitoring, technology integration, and coordination system in order to promote sustainable development of eco-environment in Xi River.

Revelation on the Drainage Systems of Ancient Villages in Jiangxi Province

Based on rural drainage problems, the research analyzed traditional water culture in ancient vil ages in Jiangxi, as wel as flood control theory, and proposed specific theories and measures for drainage system improvement and construction in order to seek proper rural drainage system and promote rural sustainable develop-ment.

Effect of Sulphur in Rainfall, Irrigation Waterand Perco colating Water on Soil Sulphur in Jiangxi Province

Ten rainfall and irrigation water-collecting posts were set up in different ecotype districts of JiangxiProvince, China, to quarterly measure S content in rainfall and irrigation water. A rainwater chemicalcomposition- collecting device was used to collect the sulphur in rainfall land the amount of sulphur adsorbedon the resin column in the device was determined. The soil percolating water was gathered using 6 lysimeters,built up according to the profile sequence of the red soil derived from red sandstone and the red soil derivedfrom Quaternary red clay, separately. On the lysimeters peanuts, soybean and radish were grown in rotation.Two treatments were designed: without S addition and with S addition at a rate of 14 kg S ha-1. The SO24contents in rainfall, irrigation water and soil percolating water were determined by the turbidimetry.The results in 1997 showed that the average annual S content in rainwater was 28.13 kg S ha-1, theaverage S content in irrigation water was 1.7 mg S L-1 , and the average content of in soil percolationwater was 2.30 kg S ha-1 year-1 and 4.70 kg S ha-l year-1 in treatments without and with sulphurapplication, respectively. In Jiangxi Province, apart from the losses by runoff and leaching, the sulphur inrainfall available to crops is 7.3 kg S ha-1 year-1 and additional S application is required. When rice isgrown , however, irrigation water can supply 6.9 kg S ha-1, which, along with the sulphur in rainfall, canalmost meet the S requirement of one cropping of rice.

Temporal and Spatial Variability of Dissolved Organic Carbon Concentration in the Xijiang River, South China

A whole year analysis of riverine dissolved organic carbon (DOC) concentrations in the Xijiang River (XJR), South China, showed that the mean riverine DOC concentration (1.24 mg L-1) in the XJR was notably lower than the averaged value (5.75 mg L-1) of the global riverine DOC concentration in several major rivers. There is an inconspicuous monthly fluctuation of the DOC signal in the XJR, but on a semi-yearly time scale, however, the riverine DOC concentration had significant difference between hydrological seasons. The DOC level during the flood season (1.18 mg L-1) was less than that during the non-flood season (1.40 mg L-1). Owing to the concomitance of the flushing and dilution effects of the runoff during the high-water period, the variation of riverine DOC concentration with discharge in the XJR differed from that reported in many other major rivers. The DOC export flux above the city of Wuzhou was about 0.62× 106 g C km-2 yr-1. The DOC transported during the "056" Massive Flood period comprised 30.35% of the annual total, while the discharge accounted for 36.32% of the total annual flow. The characteristics in riverine DOC concentration in the XJR were attributed to the combined effect of the geomorphologic, monsoon climatic and hydrological processes as well as land-use within the drainage basin.

Sensitivity Analysis of Thermal Equilibrium Parameters of MIKE 11 Model:A Case Study of Wuxikou Reservoir in Jiangxi Province of China

Sensitivity analysis of thermal equilibrium parameters in the reservoir module of MIKE 11 model was conducted for the Wuxikou Reservoir in Jiangxi Province of China in order to apply the module to the environmental impact assessment to accurately predict water temperature of reservoirs.Results showed that radiation parameter A and evaporation-first parameter were much more sensitive than other parameters.The values of the radiation parameter A ranged from 0.10 to 0.34.The values of evaporation-first parameter varied from 0 to 10.The sensitivity of solar absorption parameters was less than that of evaporation parameter,of which light attenuation values ranged from 0.5 to 0.7,and this parameter would not impact model results if it was more than 2.Constants in Beer's law ranged from 0.2 to 0.7.Radiation parameter B was not more sensitive than evaporation parameter and its reasonable range was higher than 0.48.The fitting curves showed consistent changing tendency for these parameters within the reasonable ranges.Additionally,all the thermal equilibrium parameters had much more important effects on surface water temperature than deep water temperature.Moreover,if no observed data could be obtained,the local empirical value would be used to input to the MIKE 11 model to simulate the changes in the discharged outflow-water temperature qualitatively.

Trends of Extreme Flood Events in the Pearl River Basin during 1951-2010

The study investigated the trend of extreme flood events in the Pearl River basin during 1951-2010. Stream flow data at 23 gauging stations were used for the study. The Pearson type III distribution was selected for the flood frequency analysis. Results indicate that extreme flood events increase significantly in the Pearl River Basin since 1980. At the 23 gauging stations, there are 16 (70%) stations show positive (increasing) trends in 1981-2010. Most of the 16 stations are located along the West River and North River. While 7 (30%) stations show negative (decreasing) trends, and are found in the East River and the southeast region of the West River Basin.

Value of Ecosystem Services in Conventional and Organic Rice Paddies:A Case Study in Wannian,Jiangxi,China

In the current study,the ecosystem services(ES) of conventional and organic rice paddies in Wannian,Jiangxi Province,China are investigated.First,the ES at the field level under organic and conventional paddies were investigated.Total economic value of ES in organic rice paddies was 30093.08 yuan RMB/ha per year and that of conventional rice paddies was 22 793.31 yuan RMB/ha per year.The total indirect value of ES was 14 813.7 yuan RMB/ha per year in organic rice paddies and 12 424.56 yuan RMB/ha per year in conventional ones.There were significant differences between organic and conventional rice paddies for the economic values.Then,this economic information was used to extrapolate and to calculate the total and indirect value of ES from rice paddies in Wangnian.The total and indirect economic values of ES from conventional rice paddies in Wannian were 6791 million and 3702 million yuan RMB per year respectively,and the total and indirect economic values of ES from organic rice paddies in Wannian were 1311 million and 646 million yuan RMB per year.If half the area had being converted to organic farming in Wannian,the total and indirect economic values of ES from conventional rice paddies were 3397 million and 1851 million yuan RMB per year,and the total and indirect economic values of ES from organic rice paddies were 5794 million and 2852 million yuan RMB per year.Finally,the total economic value of ES in rice paddies in Wannian was demonstrated through geographic information system techniques.

Influences of Soil Physical Properties on Water-Supplying Capacity

The water-supplying capacity of two agricultural soils, red soil in Jiangxi Province and meadow soil in Henan Province, was assessed mainly using physical investigations. The reticulated mottting horizon in the red soil was a horizon limiting roots distribution due to its high density and hardness in structure and low pH (pH 5.05). The resistance of the red soil to drought hazard was poor because of its low water-supply capacity and poor hydraulic conductivity. The meadow soil had superior profile infiltration to that of the red soil and great available water-storage capacity) which resulted in low run-off loss, especially in the wheat-growth season. It was difficult for water stored in the deep layers of the meadow soil to reach the surface due to the low unsaturated hydraulic conductivity of its clay-rich horizon in subsoil. However, water stored in deep layers was still available because the roots could extend to the deep layers due to the relatively low density in soil structure.

Spatial Layout and Morphological Characteristics of the Waterfront Settlements in Northern Jiangxi

The stmctufe types of the waterfront settlements in the north of Jiangxi Province were analyzed. According to the relationship between location and water, die waterfront setdements in northern Jiangxi were classified into tiiree categofies. The structuial commonalities of the three kinds of waterfront settlements were cleady interpreted. On this basis and combined with the field research data and relevant data, the characteristics of the waterfront setdements in northern Jiangxi were summarized： treating water as the main skeleton, choosing location by the distance ￡com watet, magnetic effect and organic textute. The characteiistic space of watetfront settLemeiits found in the investigation process was classified and elaborated, which has certain reference significance for tiie space study of waterfront settlements.

Decision Support System for Flood Control with Applications to Jiangxi Province

Affected by the climatic fluctuation and human activities, significant changes of the flood control situation are taking place in China. In the new century, the flood control systems have to face a series of challenges. In this paper, we design fa decision support system (DSS) for flood control based on its requirements. The DSS has been applied to decision-making for flood control in Jiangxi province, and play an important role in the flood control in the recent two years. Finally, we plot the further improvement on the DSS so that it will make more contribution in the flood control.

Co-integration Analysis of the Effect of Population Urbanization on Urban-rural Income Gap in Jiangxi Province

This paper selects related data on the urbanization and the incomes of urban and rural residents in Jiangxi Province from 2000 to 2014, applies the theory of co-integration by Eviews Software, meanwhile, studies and analyzes the population urbanization and the income gap between urban and rural residents in Jiangxi Province through establishing an index system. Results： There is a cause-and-effect relationship, as well as duality, between the urban-rural income gap and the level of population urbanization in Jiangxi Province. With continuous promotion of the urbanization course in 1990-2014, the income gap between urban and rural residents in Jiangxi Province presents a phenomenon of expanding first, narrowing second and expanding again.

MORPHOTECTONICS OF THE BASEMENT SURFACE OF THE WEST SIBERIAN BASIN WITHIN NADYM-TAZ INTERFLUVE

The map of reflecting horizon A, plotted on the basis of regional geophysical materials, yieldsinformation about the bottom topography of sedimentary cover of the West-Siberian Basin within Nadym-Taz interfluve. Through morphotectonic analysis about this surface, the authors are able tounderstand the distribution characteristics of the main topographic irregularities, with the blockstructure of the lower cover floors and underlying complexes as the focus.The largest irregularities are caused by the presence of three regional altitude steps, which show a regional tendency of basement being submerged in the north-north-east direction. Within these irregularities, the authors have distinguished some regions, which can be divided, based on the characteristics of morphostructural distribution, into two groups, i.e., areal (Nadym, Tol'ka, Urengoy)and belt (Tarko-Sale, Russko-Chasel'ka and Messoyakha). The first ones represent quasihomogeneous blocks, whose surfaces are complicated by irregular low-amplitude elevations and troughs and low-gradient zones with gradient values being up to 0.03, or they submerge stepwise, with the leveled areas being separated by zones with high gradients (0.07-0.15). The morphostructure of the other group of regions is characterized by the en-echelon distribution of contrastingly positive and negative elements with high values of slope gradients (higher than 0.1-0.2).