The central government has identified the construction of the Yangtze River Economic Belt as one of the three national development strategies of China in the new period. On this background, its demand for construction land will increase further. Potential of available construction land can reflect the carrying capacity of surplus construction land for the future population aggregation, industrialization and urbanization in a region. It becomes a key factor that decides whether the study area could keep sustainable and stable development. According to the multifactor algorithm and extracting process of available construction land, this article assessed the amount and spatial distribution characteristics of the potential of available construction land on the Yangtze River Economic Belt. The result found that the construction land had a tendency of increasing first, decreasing then and increasing again in the study area. In 2008, its construction land area reached 10.96×10⁴km² and the land development intensity was 5.35%. For the latter, Districts characterized by the levels of high and very high were distributed in the Yangtze River Delta, Lianghu Plain and Sichuan Basin, etc. Areas featured by the levels of low and very low were distributed in the western Sichuan, Yunnan, Guizhou and so on. Its available construction land potential was 85672.35km², which accounted for 4.18% of the total land area. In general, The total potential was small. It was higher in the north than of the south and decreased gradually in the middle reaches, the lower reaches and the upper reaches of the Yangtze River. The potential of available construction land per capita was 0.015 ha and decreased gradually in the lower reaches, the middle reaches and the upper reaches. The amount of available construction land was relatively abundant in Sichuan Basin, Lianghu Plain and the north of Anhui Province. Potential of available construction land and its per capita area were both small in the Yangtze River Delta, municipal districts of big cities and western Sichuan.

One of important regional development strategies is to achieve collaborative development and to form fair and orderly spatial distribution along Yangtze River of China in new period. Based on the data of prefecture-level cities and county-level cities, the spatial distribution pattern and transmission mechanism have been examined by spatial smoothing method, spatial autocorrelation model, High-Low clustering index, vector auto regression estimate, and Granger causality test. The results show that:① Along Yangtze River, there are three city groups reach the standard definition of urban agglomeration-Yangtze River Delta city group, Middle Reaches of Yangtze River city group, and Chengdu Chongqing city group. The layer structures are multi-centre, single-centre and double-centre respectively. ② There is a positive correlation between urban agglomerations on Yangtze River Economic Belt. The spatial distribution is HH clustering characteristic of Yangtze River Delta, LL clustering characteristic of Chengdu Chongqing area. There's no significant spatial clustering characteristic of Middle Reaches area, which shows as gray area. ③ The linkage direction is Yangtze River Delta→Middle Reaches→Chongqing and Chengdu. And there exists a lag effect. Therefore, to enhance spatial correlation between urban agglomerations along Yangtze River by unblocking spatial spillover channel is an effective measure for Yangtze River Economic Belt integration.

Whether environmental regulation will barrage technological progress has received more attention in recent years, but the relationship under the condition of open economy has been generally ignored. This paper took the 11 provinces and cities of the Yangtze River Economic Belt in 1999-2013 as research samples, empirically tested the effects of environmental regulation on international R&D spillover effect. The results showed that:(1) environmental regulation level and international R&D spillovers present a U-shaped relationship, i.e., at beginning, relatively weak environmental regulation intensity of the provinces and cities in the Yangtze River Economic Belt barraged the international technology spillovers, but with the increase of the intensity on environmental regulation and international R&D spillovers level rose; (2)different methods of environmental regulation will influence U-shaped relationship of international R&D spillovers and environmental regulation, and change the level of environmental regulation at the inflection point; (3) the level of environmental regulation in the provinces and cities of the Yangtze River Economic Belt is relatively low, mostly at the left of U-shaped. At the end of this paper, according to the above conclusions, we put forward some corresponding policy recommendations.

The safety of drinking water source supply is known to depend on the continuous improvement of management mechanism. Composed of institutions, policies, participation, information, technology and finance, Integrated Lake Basin Management (ILBM) can provide a benefitial framework for drinking water source management. Base on such a framework, the status of drinking water source management of Taihu Lake in Suzhou was analyzed. The output showed that the main problems in management include lack of effective coordination mechanism between among organizations, deficiency in policies of economic incentive, education and public participation, low level of participation and information reliability, not-closely combination of science and technology with local needs and instability of capital investment. Based on ILBM, we proposde some policy recommendations for the optimal management of drinking water sources.

This paper provided carbon reduction program for Wuhan agglomeration by measuring land-use associated carbon emission efficiency and its convergence. This paper analyzed emission efficiency, technical progress and technical efficiency of this city group. σ and β convergences were calculated to analyze the carbon emission efficiency. The results showed that the land using carbon emission efficiency rose before 2010, then declined afterward. The underlying cause is that, although the technological progress is continuously rising, it cannot compensate for the reduction of technical efficiency. Wuhan city circle could be divided into three categories according to the type of urban land. The results showed that they have suffered different degrees of convergence. At the end, a carbon reduction program was proposed based on the above analysis.

Based on the data of current velocity and suspended sediment concentration measured in the main channel of the South Passage the Changjiang estuary from January 7 to 14 in 2015, the mechanisms of water and suspended sediment transports during a neap-spring tide cycle are analyzed by using the mechanism decomposition method. Furthermore, the influence of the periodic variation of suspended sediment concentration and current velocity on the suspended sediment transport is also explored by the method of wavelet analysis. The results showed that (1) the net water transport in most tidal cycles was seaward at the measurement station, and the magnitudes of the Euler and Stokes residual current decreased gradually from the spring tide to the neap tide. (2) The net suspended sediment transport was landward in each tidal cycle; from spring tide to neap tide the magnitude of suspended sediment transport displayed a remarkable "small-big-small" variation pattern owing to the intensively tidal variation of the tidal pumping transport; advection and net vertical circulation transport terms also play an important role on the net sediment transport. (3) The results of the wavelet analysis showed that the temporal variations of suspended sediment concentration and current velocity displayed several variation periods; the combined effect of suspended sediment concentration, flow velocity and water level leaded to 2 obvious variation period in the instantaneous sediment transport rate.

In order to better understand the spatial-temporal distribution of fish in the middle reach of Yangtze River from Honghu to Yichang section in 2014 and 2015, we applied hydroacoustic analysis with Simrad EY60 split-beam echo sounder, in autumn (October to November,2014), spring (April to May,2015), and summer (July,2015). The results showed that the echo image detection of the fishes in the Yangtze River are relatively clear, and the background noise is small, the lake bottom reflected signals are strong, the fish populations of the Yangtze River is relatively small, mostly individual activities. Nonparametric test results suggested the target strength (TS) of the fish varied significantly among seasons (P<0.01), being highest in summer (-47.2±8.6) dB and lowest (-60.0±6.4) dB in spring. The horizontal distribution of fish density was not homogeneous, and varied significantly among seasons (F=151.08, P<0.01). The maximum density was 63.7 ind./1000 m3, 141.4 ind./1000 m³, and 266 ind./1000 m³ in autumn, spring, and summer, respectively. Vertically, the fish abundance followed the following order:the surface layer > the middle layer > the bottom layer, and the distribution was the same in the three seasons, and fish density varied significantly in the same water layer among 3 seasons (df=2,P<0.01). Under the homogeneity of variance, the LSD method was applied for multiple comparison of fish density between each water layer in 3 seasons. The results suggested that the fish density varied significantly between surface layer and bottom layer in autumn (P<0.05), the fish density was not significantly different between surface layer and bottom layer in spring (P>0.05), the fish density varied significantly among layers in summer (P<0.05). The distribution was possibly caused by the winter migration, feeding migratory, reproductive migration, and some other factors.

The Japanese grenadier anchovy Coilia nasus (Clupeiformesis) is a highly commercial and valuable anadromous fish species in China. Jingjiang section of the Yangtze River, as an important area for fishery resource conservation and reproduction of Japanese grenadier anchovy, is located at the connected region of lower reaches and estuary of the Yangtze River. In our study, we investigated C. nasus catches of fishing seasons from 2008-2009 and 2012-2015 and analyzed its environmental factors such as tidal range, water temperature, pressure, precipitation, turbidity and COD_Mn, and reported its upstream migration. According to fishing license recorded, the fishing period extended from 5 March to 10 May, fishing license numbers per year were between 84-95 and fishing days were 28-43 during the entire fishing period in the Yangtze Jingjiang section from 2008, 2009, 2012-2015. Anchovy numbers ranged from about 3.71 to 17.38 ×10⁴ individuals and the annual weight ranged between 3.61 to 18.26 ton respectively. In general, anchovy total annual catch showed a declining trend except for explosive growth during 2013 fishing period. Fishing intensity parameters decreased significantly during 2012-2015 compared to 2008-2009 fishing periods. Generalized additive models indicated that temperature significantly affected catch. Similar variation trend was also found in all fishing periods, and the daily catch increased with increasing water temperature. 78.8% of total catch number were recorded at a temperature between 15-23.2℃ and few individuals were recorded below 10℃.Our result suggested that a temperature<10℃ may inhibit anchovy upstream migration. Tidal range was also an important factor, and daily catch increased with increasing tidal range. 69.1% of total catch number were recorded at tidal above 2.0 m. This may be because upstream migration of anchovy relies on the tidal currents via selective tidal stream transport limiting the energy cost. Turbidity showed a non-linear negative relationship with the daily catch. Sharply declined daily catch were associated with turbidity above 100 NTU. Low turbidity, pressure, precipitation and COD_Mn did not affect daily catch significantly (P>0.05). Therefore, our findings suggested that tidal range, temperature, and high turbidity significantly affected the catch of C. nasus and accounted for the majority of the daily variation in catch level. Overall, this study is expected to benefit sustainable management of fishery resources and conservation of this species.

Cultivated land quality assessment and monitoring is one of the most important tasks in China. Cultivated land quality in Southern Jiangsu province has attracted much academics due to new problems such as heavy metal pollution. In our paper, the comprehensive quality evaluation and zoning method of cultivated land by integrating agricultural land classification, land quality geochemical assessments and soil loss prediction based on remote sensing was explored. Here, we restructured cultivated land quality assessment indicators firstly, then integrated with spatial analysis, clustering analysis and the matching analysis of farmland fertility conditions, farmland healthy level and surrounding factors, cultivated land categories of natural quality enhancing, soil pollution remediation, soil and water conservation and superior protection were established. Later, the reclamation paths according to cultivated land quality classification were discussed.#br#The empirical study in Southern Jiangsu showed that less than 65% in the cultivated land was healthy and fertilized, nearly 30% in the cultivated land is covered by poor soil, and over 5% in the cultivated land is threatened by the heavy metal pollution and soil erosion. Concretely, healthy and fertile farmland is mainly distributed in Taihu lake plains and flatlands along the Yangzte River which is in the eastern part of Mao Mountain. The cultivated land in the western part of Mao Mountain is relatively poor, and the heavy metal pollution and soil erosion indexes of farmlands in western part of areas long the Yangzte River and eastern part of Tahu lake is relatively high compared to soil environmental standard. So, it can be argued that agricultural production in southern Jiangsu is likely to meet with environmental risks which are related to cultivated land quality in some senses, and it may be a huge challenge to people's healthy in this area. We points out that farmlands reclamation strategy should be carried out rapidly in order to improve the cultivated land. Our approach improves current cultivated land assessment methods and results can be used for farmlands quality monitoring and management.

The water level and river discharges data in Yichang, Zhicheng, Shashi, Jianli and Chenglingji during 1997-2014, and the coupled with inflow, outflow and water level in Three Gorges during 2003-2014 were collected to detect the multiple dimensional spatial-temporal variations of hydrological regimes during the water storage process in Three Gorges. And the Mallat decomposition and reconstruction and spectrum analysis approaches were utilized during the analyses. The results indicate the following:(1) the water level and river discharge decrease along the Changjiang River. The annual fluctuations of water levels in different stations are in the same level, while the annual fluctuations of river discharges in the upstream region are more volatile than those in the downstream region; (2) the water regimes in the hydrological stations have the significant periodicities of 6.05, 11.78, 21.2, 30.29 and 53 months. The amplitude of water level in the peridicity of 1 year is above 2 m, while the amplitudes of water level in the other peridicities ranges from 0.08 to 0.82 m. (3) The water storage process in Three Gorges has limited impact on the water regims in the nearby hydrological stations. And the impact mainly conentrate on the trend variation, the water level and river discharge shows decrease trend after the water storage of the Three Gorges.

Modeling on runoff dynamics in Karst region of Southwest of China is nearly impossible due to high heterogeneity of carbonate structure and composition, and the shortage of observed data in site. It is helpful to know the different water processes through observing and analyzing the variation of flow output in a small watershed exit. Based on the background, this research has analyzed flow output in a whole calendar year. The results indicated that the flow output emerged only from May to October. With the influences of rainfall intensity and conversion process of interflow to surface runoff, the flow output broken out after several hours of rain, then faded out slowly in May. But the flow output gathered strength with rain in June to October and the lag-effect was shorter than in May. With exception of May, the relationship between rainfall and flow output amount was significant from June to October. There were seasonal variationsin conversion of interflow to surface flow, which determined the flow duration in exit of watershed. The amount of flow output accounted for approximately 23.1% of annual rainfall.

Black carbon has already become an important component of atmospheric pollutants which increases greenhouse effect and harms to human health. The spatial and temporal distribution characteristics of black carbon in foliar dust were studied in six different function zones in Nanjing and compared with surface dust and soils so as to investigate the distribution of black carbon in multi-medias. The results showed that the contents of black carbon in foliar dust varied greatly with seasons and rpeaked in winter. The contents of black carbon were significantly higher in industrial area than other functional zones. There was a highly significant correlation between black carbon and BC/OC, demonstrating that the accumulation of black carbon in foliar dust was strongly influenced by fossil fuels. The contents of black carbon in foliar dust were significantly higher than those in surface dust and soils of the same place, indicating that its concentration decreased gradually in the migration process from the atmosphere to the surface. Particulate matter on plant leaves can be used as an effective tool for monitoring atmospheric pollution such as black carbon.

Study of the interactions and exchange fluxes between groundwater and lake water is an important prerequisite for understanding and preserving groundwater-lake water ecosystems. The objectives of this paper are to combine observed lake water level and groundwater level (during 2014) and statistical methods to analyze the dynamics of groundwater level response to the lake water level changes around Poyang Lake. Additionally, we further explored the laterally hydraulic connection between lake water and groundwater. Statistical results showed that the groundwater depth varies from -8.1 to -0.1 m in different delta wetlands of the Poyang Lake, and the lake water and groundwater had a fully hydraulic connection during the high lake water level periods (June-September). In addition, the variations of groundwater level in the typical delta wetlands were similar to those of the lake water level, suggesting a close hydraulic connection between the two. Statistical results also showed that the groundwater depth has a range of -10~-2.2 m in different lakeshores around the lake. Although the groundwater level in different lakeshores and the lake water level are obviously different at a daily scale in terms of the temporal dynamics, they appear to exhibit similar variation pattern at a monthly scale. The wavelet analysis demonstrated that both the lake water level and the groundwater level in different areas were of obvious 60 days significant oscillation periods with the positive correlations. This result indicates that, in generally, Poyang Lake water has a close hydraulic connection with the groundwater of different delta wetlands, but a relatively weak hydraulic connection between the two depended on the local water regime. The outcomes of this study will not only help improve our understanding of groundwater-lake water dynamics in the Poyang Lake area, but also can provide scientific basis for future groundwater management and water resources assessment.

Soils were collected from estuary wetland of Shiwuli River in the Chaohu Lake region. Influences of PAM(J), PAM+biochar(SJ) and PAM+peat(NJ) amendments on soil aggregates, anti-suspension and phosphorus release were studied after flood incubation. The results showed that >0.25mm soil water-stable aggregate contents were in the order:J(58.73±0.57%) > SJ(48.27±3.58%) > NJ(34.47±2.02%) > CK (no modifier treatment)(2.31±0.15%).On the laboratory simulated experiment of wind effect, soil suspension contents and total phosphorus in water were in the order:CK > NJ > J > SJ, CK was significantly higher than the else. Compared to CK, J, SJ and NJ increased the contents of >0.25mm water-stable aggregates,and enhanced the capability of soil anti-suspension, moreover, obviously reduced soil phosphorus release into waters. The SJ, was the best treatment to promote the capability of soil anti-suspension and reduce the phosphorus release into water.

The Loess-palaeosol profile was surveyed in detail and sampled systematically at the Tuojiawan site on the first river terrace in the upper Hanjiang valley. The stratigraphic and sedimentological characteristics, pedogenic modification characteristics and the profile structure were observed in the field. Magnetic susceptibility, particle-size distribution and optical luminescence dating(OSL) were analyzed in laboratory. The results showed that TJW profile recorded the environment features and evolution with the stratigraphic series on the first terrace from the bottom to the top was listed as fluvial gravel(T_1-al1)→eolian loess and alluvial sand inter-beds(T_1-al2)→Malan loess(L₁)→transitional loess(L_t)→palaeosol(S₀)→recent loess(L₀)→modern soil(MS). Different degree of weathering intensity in different stratigraphic. The content of clay, clay/coarse silt ratio, magnetic susceptibility in the top of Malan loess were higher than those in the typical Malan loess. It was showed that the weathering intensity on the top of Malan loess (228~260 cm and 294~370 cm) was obviously higher than that on malan loess, close to the palaeosol(S₀), belongs to the weak palaeosol(L₁-S₁ and L₁-S₂). The OSL age results showed that the two layers of weak palaeosol (L₁-S₁ and L₁-S₂) were deposited between 27.3 and 21.6 ka BP. TJW loess-palaeosol sequence recorded monsoonal climate change since Pleistocene. Including the cold and arid glacial and a short time the climate was warm and wet in the glacial period(27.3~21.6 ka BP), the gradually intensified southeast monsoon during the early Holocene periods, the strongest monsoon in the mid-Holocene, and the monsoon recession and the climate drying during the late Holocene.

Based on daily temperatures data at 56 national meteorological stations in the Yangtze River Delta region during 1950 to 2014, the extreme heat events indices (extreme maximum temperature TXx, extreme minimum temperature TNn, high temperature days Htd and low temperature days Ltd) were calculated to explore the temporal and spatial distribution characteristics of extreme heat events in the region of the Yangtze River Delta for the past 60 years with the aid of GIS spatial analysis technology and Mann-Kendall trend analysis method. Furthermore, their intrinsic relation with urbanization was also studied in this paper. The results showed that:(1) Extreme heat events indices of Yangtze River Delta were all characterized by a rising trend. The linear trend of extreme low temperature indices (TNn, Ltd) was more significant than that of extreme high temperature indices (TXx, Htd). In addition, trend of extreme heat events indices of cities with higher level of economy and urbanization was the most significant. (2) Extreme heat events indices were heterogeneously distributed in the region of the Yangtze River Delta. Multi-year average of extreme high temperature indices (TXx, Htd) was high in southern and western area while relative low in northern and eastern area in this region. For extreme low temperature indices, multi-year average for TNn descended from the central to the north and south on both sides. On the contrary, multi-year average for Ltd was gradually increasing from the central to the north and south on both sides. (3) The impact of urbanization on TXx was more important than TNn. From the decade of 1990-2000 to the decade of 2000-2010, the impact of urbanization on extreme heat events indices has been enhanced with a larger influence on northern cities rather than southern ones.

Drought is one of the most damaging natural disasters, which might cause huge losses to agricultural production and the local economy. Using the Vegetation Condition Index (VCI) calculated by the remote sensing data of AVHRR and MODIS as monitoring indicators to study the temporal and spatial variation in Jiangsu Province was the first step. Then, we discuss its relationship with the four climate factors about precipitation, air temperature, relative humidity and sunshine duration according to the measured meteorological data about Jiangsu Province from 1982 to 2010. Not only could quantitatively describe the space changes in vegetation drought, it could also reflect positive or negative effect by long-term climate. The results showed that the average VCI value for nearly 30 years in Jiangsu was on a rising curve, and the overall regional drought had eased. Referring to the four climate factors, the annual average temperature rose, the annual average precipitation was essentially unchanged, while relative humidity and sunshine duration decreased. Also, temperature and relative humidity had a remarkable correlation with VCI, which were the main factors affecting the drought.

Using the TRMM satellite precipitation data and NCEP/CFSR reanalysis data of temperature, high and wind filed from 1998 to 2013, the characteristics of diurnal variation of Meiyu season precipitation and convection over the Yangtze River Basin were revealed from the point of Climatology. The difference of diurnal variation of rainfall between typical and non-typical Meiyu years, the diurnal variation characteristics of atmospheric elements and their effects on the precipitation and convection were also analyzed. The results showed that, (1) the intense rainfall mainly occurred in the eastern Tibetan Plateau to the Sichuan basin during the night, in the middle and lower reaches of the Yangtze River during the day. The features of diurnal variation of precipitation were significant. The precipitation day peaks in the eastern Tibetan Plateau to the Sichuan basin, the middle reaches of the Yangtze River and Southern China respectively occurred on the middle night, 08 h early morning and 17 h late afternoon. The rainfall in the Yangtze-Huaihe river basin showed semidiurnal cycle, with the two peaks of 08 and 17 h, the afternoon peak was much stronger than the morning. (2) The daily rainfall in the middle reaches was delayed 6 h than the upper reaches of Yangtze River, the lower reaches was further backward, but the intensity and scope of precipitation was much stronger than the upper reaches. (3) The distribution of diurnal variation of typical Meiyu year is consistent to the nearly 15 years of Meiyu season average. The evolution form of non-typical was similar to the above two, only the daily peak time was ahead. (4) The short-time heavy rainfall had a good relationship to the deep convection. The high frequency area was happed in the lower reaches of Yangtze River (the eastern Tibetan Plateau to the Sichuan basin) during the day (night). (5) The diurnal variation of atmospheric temperature and pressure caused the intensity and structure differences of Meiyu front between the day and night. The lower troposphere wind speed was found to gradually weaken in the day, increase in the night, and produced diurnal variation of position of convergence at low level wind filed. These resulted in the diurnal variation of the rainfall and convection of Meiyu season.