Effects of Groundwater with Various Salinities on Evaporation and Redistribution of Water and Salt in Saline-sodic Soils in Songnen Plain,Northeast China

Groundwater mineralization is one of the main factors affecting the transport of soil water and salt in saline-sodic areas. To investigate the effects of groundwater with different levels of salinity on evaporation and distributions of soil water and salt in Songnen Plain, Northeast China, five levels of groundwater sodium adsorption ration of water(SARw) and total salt content(TSC mmol/L) were conducted in an oil column lysimeters. The five treated groundwater labeled as ST0∶0, ST0∶10, ST5∶40, ...     

Types and Optimization Paths Between Poverty Alleviation Effectiveness and Rural Revitalization: A Case Study of Hunan Province,China

Exploring the synergy types and optimization paths between Poverty Alleviation Effectiveness and Rural Revitalization is necessary for achieving the two centenary goals. Taking poverty alleviation counties in Hunan Province, China as an example, our study proposed an indicator to measure the synergistic development between Poverty Alleviation Effectiveness and Rural Revitalization using the multi-index integrated evaluation method. Then, the coupling types were classified based on both the propo...     

Influence of rainfall-induced diabatic heating on southern rainfall-northern haze over eastern China in early February 2023

In early February 2023, there was severe haze on the North China Plain(NCP) that was contemporaneous with heavy rainfall over southern China, which was known as southern rainfall-northern haze(SR-NH). Based on observational and reanalysis data, the meteorological causes of this SR-NH event are investigated in this study using correlation analysis, dynamic diagnostics and numerical experiments. The results show that the anticyclonic anomaly in the Pacific Northwest(also referred to as the northea...     

Influence of river-lake isolation on the water level variations of Caizi Lake,lower reach of the Yangtze River

In order to explore the water level variations of Caizi Lake under river-lake isolation,the monthly water level of the Chefuling station in Caizi Lake from 1989 to 2018 and the daily water level,rainfall and flow of local hydrological stations in 2018 were analyzed by using the Mann-Kendall trend test and wavelet analysis.Results showed that the difference of the average water level of Caizi Lake between the flood and dry seasons was 3.34 m,with a multi-year average water level of 10.42 m above sea level.The first and second main periods of the water level of Caizi Lake were 128 and 18 months,respectively,with 4 and 29 "up-down" cycles,respectively.From 2018,the next 3-4 years were likely to be the low water level period.The water level of Caizi Lake was significantly correlated with that of the Anqing hydrological station of the Yangtze River (r=0.824,P＜0.01).In addition,the current hydrological staging of Caizi Lake was about 30 days behind than before the sluice was built.Under the dual influences of the river-lake isolation and the Yangtze-to-Huaihe Water Diversion Project (YHWD),the hydrological regime change of Caizi Lake and its eco-environmental effect needed long-term monitoring and research.     

Surface Processes Driving Intracontinental Basin Subsidence in the Context of India–Eurasia Collision: Evidence from Flexural Subsidence Modeling of the Cenozoic Southern Tarim Basin along the West Kunlun Foreland, NW Tibetan Plateau

The India–Eurasia collision has produced a number of Cenozoic deep intracontinental basins, which bear important information for revealing the far-afield responses to the remote collision. Despite their significance, their subsiding mechanism remains the subject of debate, with end-member models attributing it to either orogenic or sedimentary load. In this study, we conduct flexural subsidence modeling with a two-dimensional finite elastic plate model on the Hotan–Mazatagh section along the southern Tarim Basin, which defines a key region in the foreland of the West Kunlun Orogen, along the NW margin of the Tibetan Plateau. The modeling results indicate that the orogenic load of West Kunlun triggers the southern Tarim Basin to subside by up to less than ~6 km, with its impact weakening towards the basin interiors until ~230 km north from the Karakax fault. The sedimentary load, consisting of Cenozoic strata, forces the basin to subside by ~2 to ~7 km. In combination with the retreat of the proto-Paratethys Sea and the paleogeographic reorganization of the Tarim Basin, we propose that surface processes, in particular a shift from an exorheic to an endorheic drainage system associated with the consequent thick sedimentary load, played a decisive role in forming deep intracontinental basins in the context of the India–Eurasia collision.     

Spatiotemporal Dynamics of Green Total-factor Water-use Efficiency and Its Influencing Factors in China

In this study, we developed an evaluation index system for green total-factor water-use efficiency(GTFWUE) which reflected both economic and green efficiencies of water resource utilization. Then we measured the GTFWUE of 30 provinces/municipalities/autonomous regions(hereafter provinces) in China(not including Tibet, Hong Kong, Macao, Taiwan as no data) from 2000 to 2018 using a minimum distance to the strong frontier model that contained an undesirable output. We further analyzed the regional ...     

Spatial Differentiation and Influencing Factors of Poverty Alleviation Performance Under the Background of Sustainable Development: A Case Study of Contiguous Destitute Areas in Hunan Province,China

Poverty eradication is a realistic requirement for the addressing of the urban-rural development imbalance. It consolidates the achievements of the poverty alleviation, and accelerates the realization of the United Nations Sustainable Development Goals. In research that deals with poverty, qualitative analysis is often used to study the connection between a single influencing factor and poverty reduction, and to solve regional poverty through government measures. However, these studies usually i...     

Surface Rupture and Co-seismic Displacement Produced by the Ms 8.0 Wenchuan Earthquake of May 12th, 2008, Sichuan, China: Eastwards Growth of the Qinghai-Tibet Plateau

An earthquake of Ms 8 struck Wenchuan County, western Sichuan, China, on May 12^th, 2008 and resulted in long surface ruptures （〉300 km）. The first-hand observations about the surface ruptures produced by the earthquake in the worst-hit areas of Yingxiu, Beichuan and Qingchuan, ascertained that the causative structure of the earthquake was in the central fault zones of the Longmenshan tectonic belt. Average co-seismic vertical displacements along the individual fault of the Yingxiu-Beiehuan rupture zone reach 2.514 m and the cumulative vertical displacements across the central and frontal Longmenshan fault belt is about 5-6 m. The surface rupture strength was reduced from north of Beichuan to Qingchuan County and shows 2-3 m dextral strike-slip component. The Wenchuan thrust-faulting earthquake is a manifestation of eastward growth of the Tibetan Plateau under the action of continuous convergence of the Indian and Eurasian continents.     

Very Low-Grade Metamorphism of Clastic Rocks from the Meso-Neoproterozoic and the Paleozoic along the Profile Yueyang-Linxiang in Northeastern Hunan Province and Its Geological Implications

This study uses illite crystallinity,chlorite crystallinity,illite polytypes,the b_0 cell-dimension of K-white mica,clay mineral assemblages and mineral geothermo-geobarometers to investigate the overprint of diagenesis and metamorphism on the Meso-Neoproterozoic and the Lower Paleozoic along the profile Yueyang-Linxiang in northeastern Hunan Province,China.Illite crystallinity Kbler index(KI) of the 2μm fractions ranges from 0.225 to 0.485°Δ2θ while chlorite crystallinity Arkai index(AI) ranges from 0.244 to 1.500°Δ2θ.This indicates that the Meso-Neoproterozoic and the Lower Paleozoic along the profile Yueyang-Linxiang were overprinted with diagenesis and anchi- to epimetamorphism.Peak metamorphic temperature is estimated with the IV site chlorite geothermometer roughly at 360℃.The b_0 cell dimension values of illites(K-mica) range from 0.9002 to 0.9054 nm and,on average,at 0.9030 nm for the Meso-Neoproterozoic.Based on cumulative frequency curves of illite(K-mica) b_0 cell dimension,the peak metamorphic pressure of the MesoNeoproterozoic along the profile Yueyang-Linxiang is derived of an intermediate pressure type.Most illites occur in the 2M_1 polytype and some of them in a mixture of 2M1+1M types especially those in the Paleozoic.This result partly agrees with the conclusion of the lower greenschist and greenschist facies of the Lengjiaxi and Banxi Groups.However,it is not agreed with the sedimentary cover from the Sinian to the Lower Paleozoic or from the Banxi Group to the Lower Paleozoic.Crustal thickening due to "collision" between the Yangtze and Cathaysia blocks led to an increase in the thickness of the Meso-Neoproterozoic to ca.14 km and resulted in a temperature increase in those rocks due to burial.The very low grade to low grade metamorphism overprinting the Meso-Neoproterozoic implies that the so called "Chiangnania or Jiangnan orogen" was no relative with the "Grenvillian orogeney;instead,it might be a continuous amalgamation product between the Yangtze and Cathaysia blocks.     

Controls on the Northward Movement of the ITCZ over the South China Sea in Autumn: A Heavy Rain Case Study

The autumn Intertropical Convergence Zone(ITCZ) over the South China Sea(SCS) is typically held south of 10°N by prevailing northeasterly and weakening southwesterly winds. However, the ITCZ can move north, resulting in heavy rainfall in the northern SCS(NSCS). We investigate the mechanisms that drove the northward movement of the ITCZ and led to heavy non-tropical-cyclone rainfall over the NSCS in autumn of 2010. The results show that the rapid northward movement of the ITCZ on 1 and 2 October was caused by the joint influence of the equatorial easterlies(EE), southwesterly winds, and the easterly jet(EJ) in the NSCS. A high pressure center on the east side of Australia, strengthened by the quasibiweekly oscillation and strong Walker circulation, was responsible for the EE to intensify and reach the SCS. The EE finally turned southeast and together with enhanced southwesterly winds associated with an anticyclone, pushed the ITCZ north. Meanwhile, the continental high moved east, which reduced the area of the EJ in the NSCS and made room for the ITCZ. Further regression analysis showed that the reduced area of the EJ and increased strength of the EE contributed significantly to the northward movement of the ITCZ. The enhancement of the EE preceded the northward movement of the ITCZ by six hours and pushed the ITCZ continually north. As the ITCZ approached 12°N, it not only transported warm moist air but also strengthened the dynamic field by transporting the positive vorticity horizontally and vertically which further contributed to the heavy rainfall.