Existing urban geographical studies on city network are mainly based on gravity models, visualization of transportation flows and inter-locking network models. However, these methods only provide a biased picture of the whole city network since they are either based on hypotheses in theoretical or empirical models or just a depiction of one specific aspect of inter-city connections. Moreover, the studies on world city network led by the GaWC group emphasize more of the hierarchical structure of city network than inter-city cooperation. This paper aims to explore a more efficient method to measure the inter-city cooperation based on the joint intellectual property data. The analysis of inter-city innovation cooperation may also provide insights into a new aspect of inter-city connections, which is complementary with previous studies focusing on transport network or head-branch relations of firms. Using the Yangtze River Economic Belt as a case, in this paper we found that the inter-city innovation cooperation was mainly inter-firm or intra-firm links, the university-firm cooperation only took a small proportion. We also revealed that innovation connections were dissymmetric between different levels of cities in terms of forms of cooperation and there were significant spatial differences among different regions. The innovation connection among cities followed the Zipf law and was positively yet not significantly related to that calculated based on the gravity model. The results from regression analysis suggest that inter-city innovation connections are influenced by the spatial distance, gap of administrative level and industrial similarity.

Transportation network is the basis of economic development. Analysis of the differences in the spatial pattern of accessibility is of great significance for population distribution and construction of transportation facilities. By using weighted average travel time as an indicator of accessibility, in this research we first calculated the accessibility of highway, railway, waterway, civil aviation, and integrated transportation in China with 2 317 counties as the basic analysis units. Second, we analyzed the geographic patterns of accessibility, which showed that (1) highways formed a "core-periphery" pattern with Zhengzhou, Wuhan, and Hefei at the cores; (2) the geographic pattern of railway accessibility showed a belt pattern that resembled the expansion of the transport network; the center of accessibility moved toward to Hefei and Nanjing; (3) the accessibility of civil aviation gradually decreased from hub airports to the trunk and feeder airports and displays a hub-and-spoke pattern; (4) the accessibility of waterways declined gradually from the coast to the inland; and (5) the integrated transportation accessibility had a reverse-to-natural gradient. The overall level of accessibility of four transportation modes was high with 70% above the average value of accessibility. For most of counties, transportation accessibility presented a distribution of "high in the east and low in the west" and was related with population distribution in China. Inequality of accessibility still existed in the internal region. Finally, some suggestions were put forward to deal with these problems.

From the perspective of the push-pull theory, in this paper we analyzed the push and pull factors of rural homestead's exit, from the two angels of rural homestead as resource and asset attributes as well as farmers owning the use right of rural homestead migrating to the city. Based on the above framework of theoretical analysis and the rural survey data obtained by questionnaire in the Qixia District, Nanjing, we included the main push and pull factors that influence the willingness of rural homestead's exit through building a binary Logistic model. We found that education level, total annual income of farmers, number of people living in the household and whether participating in the rural endowment insurance are the main push factors of homestead's exit; while ratio of non-agricultural income, number of migrant workers, whether participating in urban endowment insurance, whether having urban dwellings, whether having homestead's property certificate and perception of homestead's mortgage rights are the main pull factors of homestead's exit. Based on the theoretical and practical research, we put forward policy suggestion for improving exit mechanism of homestead.

Cropland, woodland and wetland (pond) were three main typical habitats for amphibians in rural Shanghai, the difference of habitats and amphibian ecological characteristics caused diverse distribution of amphibians. From May to August in 2014 and 2016, amphibian biodiversity survey were conducted in 30 study sites of three typical habitats in rural Shanghai. One-Way ANOVA was used to compare the amphibian community structure across three habitats in rural Shanghai, hierarchical clustering method was undertaken to analyze the similarity of amphibian community structure in different habitat. The results showed that a total of 5 397 anuran individuals were recorded in two years, belonging to 1 order, 4 families, 4 genera and 5 species. The dominant species of amphibian in rural Shanghai were Fejervarya multistriata and Pelophylax plancyi, meanwhile Pelophylax nigromaculata, Bufo gargarizans and Microhyla fissipes were common species. All five amphibian species were defined as wide distribution species. There were significant differences in the species richness of amphibian among the rural habitats, but we did not find any corresponding significant differences in the abundance. F. multistriata and M. fissipes had a significant higher population density in cropland habitat. P. nigromaculata and P. plancyi had a significant higher population density in pond habitat. We did not find significant difference in population densities of B. gargarizans among different habitats. The results of cluster method indicated that woodland and pond habitats were classified into the same group, however, the cropland habitats were classified into another one. Our study suggests that habitat protection and restoration in rural Shanghai is one of the key issues to undertake the biodiversity conservation for amphibians.

The community structure of rotifer and its relationship with environmental factors in Lake Gehu were investigated seasonally in 2013. The results showed that totally 55 species belonged to 23 genera were identified in this study, with 44 indicator species for pollution. Keratella quadrala, K. cochlearis, Polyarthra vulgaris, P. dolichoptera, Brachionus calyciflorus, B. angularis, Filinia longisela, and Asplanchna priodonta were the mainly dominant species during our study period. The annually average density and biomass of the rotifer were 1 820.0 ind./L and 2.93 mg/L, respectively. The total density reached the maximum in autumn (3 555.0 ind./L) and in the south part (2 655.0 ind./L), while the biomass was highest in spring (6.31 mg/L) and in the north part (3.26 mg/L). The distribution of rotifer community showed significantly difference seasonally rather than spatially. Pearson correlation analysis and multiple regression analysis indicated that COD_Mn and TN played a key role in the succession of rotifer communities. Currently, Lake Gehu presents a eutrophicated status, according to the comprehensive evaluation results of the dominant indicator species and biodiversity index of rotifer communities.

To explore the status of fish assemblage characteristics and historical changes, investigations on fish assemblage were carried out in the Xiaojiang River of Three Gorges Reservoir in spring (May), autumn (September) and winter (December) of 2016. A total of 37 fish species were collected, belonging to 6 formes and 11 families, among which 2 species were endemic to the upper reaches of the Yangtze River, such as Hemiculer tchangi and Procypris rabaudi. Cypriniformes were dominant, accounting for 64.86% of the total species captured. The main commercial fish species were from the Cypriniformes, including Ctenopharyngodon idellus, Squaliobarbus curriculus, Elopichthys bambusa, Carassius auratus Cyprinus carpio, Hypophthalmichthys molitrix, and Aristichthys nobilis in the Xiaojiang River. Compared with the historical data, the similarity index is low (0.45), and the composition of the main commercial fishes were changed. At the same time, species diversity and resources of indigenous fish showed a declining trend and the endemic species had significant degradation, while the fish adapting to the hydrostatic or slow-flowing water environment was on the rise in the Xiaojiang River. Over exploitation, artificial drainage system construction, illegal dredging are potential underlying reasons for observed shifts in the fish assemblages. The results suggest that the reasonable drainage patterns (Hanfeng Lake) is of great significance to protect the indigenous fish resources in the Xiaojiang River

In order to better understand the status, main threats and conservation measures of fish resources of the lower reaches of Heishui River before the operation of the Baihetan hydropower station, a catch survey using the electrofishing equipment was conducted monthly from January to December in 2014. The results showed that:a total of 28 species of fish belonging to 3 orders, 8 families and 23 genera were collected during the 12 months, among them many fish species were the ones that prefer to running water, spawn the sticky and demersal egg and feed mainly on periphyton or/and benthic organism. The fish individuals were generally dominated by small size ones and the main economic fishes in the investigated area were Schizothorax prenanti, Paracobitis potanini, Paracobitis varigatus, Schizothorax wangchiachii, Triplophysa anterodorsalis, Glyptothorax sinense and Pseudobagrus emarginatus. The catch structures between the first half and the second half of this year were statistically significant (R=0.81, p<0.05) and the mutual migration between the mainstream of the Jinsha River and the lower reaches of the Heishui River was obvious. The values of the catch per unit effort (CPUE) firstly displayed fluctuated decline and then showed a monthly increasing trend, and the value of CPUE on October was lowest among 12 months. The abundance biomass comparison curves showed that the catch structure were in a state of severe disturbance in the months of 2014. Before the filling of the Baihetan Reservoir, the sand extraction and overfishing were the main factors that affected the fish resources of the lower reaches of Heishui River, thereby the protection measures including the controls for the sections and times of sand extraction and the comprehensive fishing ban in the lower reaches of the Heishui River should be applied for protecting the fish resources of this region.

The aim of this study is to evaluate water stress of agricultural production in Jiangsu Province of China. Two water stress assessment indices, i.e., BWSI and GWSI, was established in the blue-green water framework base on regional generalized agricultural water resources and crop water footprint quantification. Then, we analyzed crop-water relationship and water stress of agricultural production for Jiangsu Province and its three sub-regions, i.e., Northern Jiangsu, Central Jiangsu and Southern Jiangsu, during 1999–2013. Results showed that, the annual average of generalized agricultural water resources of the province in the observed period was 103.46 Gm³; green and blue water accounted for about 70.4% and 29.6% of the total water resources respectively; generalized agricultural water resources in the sub-region of Southern Jiangsu was more plentiful than the Northern Jiangsu and Central Jiangsu. Yearly water footprint for crop production was estimated to be 106.95 Gm³ during 1999–2013 and the proportion in total water footprint as a whole of blue, green and grey water footprint was 5.9%, 74.6% and 19.5%, respectively. Crop water footprint of the sub-region of Northern Jiangsu increased over time, and accounted for about 61.6% of the provincial value in the study period. The annual average of BWSI and GWSI in 1999–2013 of Jiangsu province were calculated about 2.60 and 1.09, respectively, revealing a severe water stress facing the province in agricultural production. Both of the indices BWSI and GWSI showed a slight increase trend in the latest fifty years. From the perspective of spatial pattern, water stress of agricultural production increased from south to north. Temporal trend of the three sub-regions were found that three was a decrease in Southern Jiangsu, stability in Central Jiangsu and an increase in North Jiangsu. About 18.52 Gm³ of water diversion, mainly from Yangze River, was supplied for agricultural production in Jiangsu province. For all that, the BWSI and GWSI was reduced from to 2.65 and 1.09 to 2.02 and 1.01 during the period of 2001–2013. In addition to cross-regional water diversion, efficient use of green water resources and water footprint regulation should be emphasized for regional water stress relief. BWSI and GWSI can be used to evaluate the regional water stress of agricultural production. In addition, BWSI can reveal water scarcity in water-scarce areas, while GWSI is more suitable for fully reflecting water use in water-rich areas compared to the conventional water stress index (WSI). The findings of this study can supply some implications for regional water resources management.

A systematic survey on concentrations of Cd, Cu, Pb and As in eight kinds of vegetables and their corresponding soils at 10 sampling sites near the Daye Copper Plant in Daye City, Hubei Province, China, was carried out for assessing heavy metal pollution, bio-concentration ability and potential health risk to local inhabitants due to exposure via consumption of vegetables. The results showed that the soils of the studied vegetable plots were seriously contaminated by heavy metals and the mean concentrations of Cd, Cu, Pb and As reached 5.28 mg/kg, 193.37 mg/kg, 93.83 mg/kg and 36.56 mg/kg, and are 31.06, 6.30, 3.51 and 2.97 times of background contents of the corresponding heavy metals in the soils of Hubei Province, respectively. The pollution characteristics of multi-metals in soils are mainly reflected by Cd. The proportions of vegetable samples which Cd and Cu concentrations exceeded the Maximum Levels of Contaminants in Foods (GB2762-2012) were 68% and 6%, respectively. The values of bio-concentration factor from soil to edible part of vegetable decreased in the order of Cd > Cu > As > Pb, and the bio-concentration factor values of all heavy metals in the edible part of leafy vegetables were higher than the non-leafy vegetables. The soils and vegetables were heavily polluted by heavy metals, as shown by the influence index of comprehensive quality of soils and vegetables is 10.07. The consumption of the polluted vegetables would lead to potential health risk especially for children, since both THQ values of Cd and As via the consumption of polluted vegetables were above 1. The total metals THQs for adults and children were 2.11–5.06, 2.78–6.64, respectively, due to consumption of vegetable around the plant. The potential health risk for local residents living nearby Daye Copper Plant is serious due to the combined heavy metal in vegetables.

Paddy rice is an important crop in China. Extracting rice planting information timely and accurately is of great significance for food policy, food security and agricultural development. However, there are two difficulties in extracting rice planting information based on remote sensing in Southern China. One is the paddy rice growth period is accompanied by abundant precipitation. This makes the remote sensing imagery influenced by serious "cloud contamination". The other one is the cultivated land is not concentrated, making the crop classification result influenced by the phenomenon of "salt and pepper". To solve the problem of lacking available data in extracting paddy rice planting information based on remote sensing, we used Spatial and Temporal Data Fusion Approach (STDFA) to fuse the Landsat 8 and time-series MODIS images and gained the data which had the same temporal resolution with MODIS data and the same spatial resolution with Landsat 8 images. The correlation of reflectance about the red and near-infrared of fused data and true data is 0.84 and 0.81. To address the phenomenon of "salt and pepper", we used the object oriented image analysis method to derive the fusion result into several image objects and then classify and map the rice distribution in the study area. Using multi-temporal data has a higher accuracy relative to use single phase data in crop mapping, and that method has become an important way to crop classification based on remote sensing. Normalized difference vegetation index (NDVI) is widely used in vegetation classification. Based on the above two points, we used the time-series red and near-infrared data to calculate the time-series NDVI of each image object. Mostly, time-series NDVI data obtained by satellite included various noise components. To obtain change characteristics of NDVI before and after harvest of winter wheat, we used the HANTs filtering method for nosie reduction. Then we used the NDVI data to map the paddy rice fields though Support Vector Machine (SVM) method. We built the confusion matrix though the samples which came from field measurements and validated the extraction accuracy of rice. The Kappa index is 0.91 and the total classification accuracy is 93.16%. The result showed that:(1) Spatial and Temporal Data Fusion Approach has the ability to rebuild the time-series data which has had the high temporal resolution and the high spatial resolution in Southern China; (2) The object-orient method shows a high accuracy in mapping the paddy rice, suggesting that the object-orient classification method can also reduce the "salt and pepper" phenomenon in the clutter blocks.

The conditions of terrain and climate are complex in southern Qinling Mountains one of the main planting area of rape. Studying the effect on the change characteristics of agricultural climate resources, can contribute to the effective use of climate resources, reasonable arrangements for farming activities of rapeseed production. Based on the daily meteorological data of 35 stations in 1960–2014 in southern Qinling Mountains and nearly 25 years of provincial statistical yearbook, we analyzed the change characteristics of agricultural climate resources in southern Qinling Mountains and the influence on the rape production using the moving average, linear trend estimation, grey correlation analysis methods. The results showed that:(1) In the past 55 years, average temperatures and ≥ 5°C temperature showed an extremely significant increasing trend, the average rate was 0.2 and 29.3°C/10a. The freezing index, precipitation, flowering period of precipitation and relative humidity and sunshine hours showed decreasing trends, with average reduction of 0.3, 14.8 mm, 1.4 mm, 0.6%, and 32.2h for every 10a, respectively. (2) The average spatial distribution of average temperature and ≥ 5°C temperature were decreasing from southwest to northeast, and the freezing injury index and spatial distribution showed an opposite trend, indicating that winter extreme minimum temperature from southwest to northeast gradually decreased. The average spatial distribution of water resource index decreased from south to north, while sunshine hours increased from southwest to northeast. (3) The average temperature and ≥ 5°C temperature showed a significant increasing trend. A relative small changing amplitude was observed in the west, while a relative large one was observed in the east of the region. Similar spatial variation was observed for the freezing index. water resources and sunshine hours had a significant decreasing trend, only a few sites showed a significant increasing trend, the sunshine hours in the eastern part of the study area changed significantly, the area change rate was relatively small. On the whole, for average temperature and ≥ 5°C temperature, small changing ranges were present in the high value area of the agricultural climate resource index, while large changing ranges were present in the low value area. (4)In recent 25 years in southern Qinling Mountains the rape climate yield upward trend was not obvious, the average rate of 3.79 kg/(a·hm²), the spatial amplitude difference is big, and the change trend of most of the site were not significant; different main influencing factors by the correlation function in each region for meteorological yield of rape, and the greater the change range of the agricultural climate resource index, the greater the impact on the yield of rape.

Based on the remote sensing monitoring data of land use in 2000, 2005, and 2010, we utilized GIS technology to analyze the change mode, process and regional characteristics of land use in the Yangtze Basin and changes of ecosystem service functions. The results showed that from 2000 to 2010, a significant increase was present in the areas of urban and rural construction lands, woodlands and water s while the area of arable lands and grasslands continued to reduce. The reduction of arable lands was related to the increase of urban construction lands; while reduction of arable lands and grassland s was a result of increase in woodland; increase of water area was assocaited with Three Gorges water storage and returning farmland to the lake. Land use in hot spots of human activities like Sichuan Basin, midstream urban agglomeration and Yangtze Delta urban agglomeration obviously enhanced. Affected by changes of land use, the total value of ecosystem services in Yangtze Basin continued to increase from 2000 to 2010, with strengthened water conservation, waste management and entertainment and cultural services while soil formation and protection, good production and service functions were significantly weakened. High-value ecological service areas mainly included areas along lakes and wetlands, followed by areas covered by woodlands and grasslands. Tibetan Plateau desert area embodied the lowest ecological service value

With the rapid development of industry and transformation of agricultural production, the phenomenon of eutrophication in Taihu Basin is becoming more and more serious, which poses a great threat to the ecological environment in the basin. This paper used land use data of six periods and daily rainfall data from 1984 to 2013 as the main input variables in the model. According to the land use data, we divided the time interval into six time periods. With the SWAT model (the Soil and Water Assessment Tool which can simulate soil water sediment and nutrient) to simulate the nutrients export in the study area of these six different periods, we calculated nutrients export in the past three decades (1984–2013) in the northwest of Taihu Basin. According to the model results, we explored the relationship between nutrients export, rainfall, runoff and the land-use change. The data of runoff and water quality recorded by the Yixing water station from 2009 to 2013 was used to calibrate and validate the model. The coefficient of determination R² of total nitrogen and total phosphorus in calibration period was 0.76 and 0.92, respectively. The Nash coefficient of total nitrogen and total phosphorus was 0.76 and 0.79, respectively. The coefficient of determination R² in the validation period was 0.66 and 0.95 and the Nash coefficient was 0.6 and 0.54, respectively. The results suggest that nutrients export was significantly correlated with the amount of rainfall and runoff over time, which were mainly concentrated in May to August every year, and were low in November to February of next year. However, this correlation was not significant in the space. Nutrients export was closely related to land use types, and the main nutrients export in the study area was concentrated in urban lands and agricultural lands. Agricultural lands were the main source of nutrients in the study area, but the flux of nutrients export in urban lands was higher than that in agricultural lands. The types of land use in study area showed a pattern of wasteland > urban land > agricultural land > forest in terms of flux of nutrients export. The spatial distribution of nutrients export was also closely related to the spatial distribution of land use types. The export of nutrients in urban lands and agricultural lands was relatively higher than other land uses. This study will provide theoretical support and data base for the control and management of non-point source pollution in Taihu Basin.

Although mixing in lakes has significant environmental and ecological implications, knowledge of mixing dynamics for shallow floodplain lakes has received little attention. In this study we used a combination of hydrological and thermal investigations to provide evidence for the mixing in a large, shallow floodplain of Poyang Lake (China). Depth profiles of water temperature and stable hydrogen and oxygen isotope compositions were measured throughout the lake. Results showed that although the water temperature differences of up to 1.5°C were observed occasionally during the high lake water level period, Poyang Lake appeared to have isothermal mixed-layers from the upper epilimnion to the bottom hypolimnion attributed to the presence of mostly small temperature differences (0.5–1°C). The stable isotope composition revealed that the water columns of the lake were almost homogeneous during low and high lake water level periods. Poyang Lake appears to be well mixed or full mixing on a seasonal basis, depending on hydrological forcing within the lake, rather than meteorological conditions. Additionally, the vertical mixing of Poyang Lake appeared to have a close relationship with the aquatic environment due to mostly small differences in the vertical distributions of suspended sediments, TN and TP. The current study is the first to explore the stratification of Poyang Lake, which will help to improve our knowledge of water flow patterns and pollutant transport within the lake.

Water quality of the Three Gorges Reservoir from 2000–2015 was analyzed, in order to investigate the trends of water quality parameters and the relationship between the key pollutants such as suspended substance(SS), potassium permanganate index (COD_Mn), and total phosphorus (TP) from the Three Gorges Reservoir storing up to 175 m. Results revealed a good water quality in the area of the mainstream of the Three Gorges Reservoir and a less pronounced influence by the reservoir scheduling. The observed trends differed among the monitoring sections along the mainstream owing to the change of hydrologic character, upland water, branch inflow as well as non-point and point sources pollution resulted from the impoundment. The proportion of evaluation results of water quality that better than Class Ⅲ was increasing in the whole reservoir except the Qingxichang and Tuokou sections. Influenced by impoundment, water quality declining was found in Yulinhekou, Xiaojianghekou, Daninghekou and Xiangxihekou sections. Although a good correlation between the SS concentration and the period was observed for the upland water of the Three Gorges Reservoir, SS concentration was reduced during each period since 2013, which resulted in a reduction about of 80% for SS flux. SS concentration was decreased temporally during the high-flow period and normal-flow period in both the center and head region of the reservoir, but was stable during the low-flow period. After the impoundment, a lower value of SS was usually found in the main branches estuary compared with that in the mainstream of the reservoir at the same time. Meanwhile, the value of SS in the upper branches estuary was influenced by the flow period more obviously than that in the middle and lower branches of the reservoir. COD_Mn and TP differed significantly among different periods. During the high-flow period, the variation of COD_Mn and TP in the upstream sections was obviously than that in the downstream sections. After impoundment, COD_Mn and TP showed no significant differences among the periods and sections. Limited correlation was observed between SS, COD_Mn and TP, however, the results cannot be derived from the detect value of one sample in a long time.

Based on the comparative analysis between the simulation data from the high-resolution regional climate model (CCLM) and the CN05.1 data based on the observation in the reference period (1961–2005), we conducted projections on future climate change under the scenario of RCP4.5 at both annual and seasonal scales for the Hubei Province. The results showed:(1)CCLM presented a satisfactory simulation performance on the changing trend of temperature and its spatial distribution pattern, but was not matched very well with the CN05.1 observation precipitation data. (2)Under the RCP4.5, from 2006 to 2050, T, T_min and T_max in Hubei Province show a rising trend. The temperature is projected to be rising in all four seasons, while the winter has the fastest increase and the greatest contribution to the rise of annual T, T_min as well as T_max. (3)Under the RCP4.5, in the period of 2006–2050, T, T_min and T_max will increase in the whole region compared to the reference period. The region with the high increase of temperature is located in the northern part of Hubei section of Han River. In spring, the regions with high increase of temperature are located in northwestern mountain area. In summer, the increase of T, T_min and T_max in the middle plain region is higher than other regions. In fall, the increase of T and T_max in southwestern mountain region is higher than that in other regions. The regions with high increase of T_min are located in the northern part of Hubei section of Han River. In winter, the increase of T in hilly regions of southeastern Hubei is higher than that in other regions, the same for the T_min in north part of north section of Han River and T_max in southwestern mountain region.

Potential evapotranspiration (PET) is crucial to water resources assessment and climate change. Based on the Penman-Monteith equation proposed by Food and Agriculture Organization (FAO) and daily meteorological data of 90 meteorological stations in Southwestern China, daily potential evapotranspiration at 90 meteorological stations was calculated. Then, various statistical methods were used to analyze its spatial and temporal variations. The results showed that the mean annual potential evapotranspiration in the whole Southwestern China during the recent 52 years was 3 209.8 mm, the highest potential evapotranspiration value was observed in Yunnan Province (3 664.7 mm), followed by Sichuan Province (3 015.0 mm), Guizhou Province (2 958.0 mm), and Chongqing Municipality (2 972.4 mm). PET in summer was the highest, followed by spring, autumn and winter. Distribution characteristics of four seasons are different from that of annual mean. Moreover, the linear changing trend of potential evapotranspiration in Southwestern China was 0.9 mm/10a. There are 31 stations showing a decreasing trend (p<0.1) and 17 stations showing an increasing trend (p<0.1). Decreasing PET in spring and summer was found at 55.6% and 63.3% of all stations, respectively. While increasing PET in autumn and winter was found at 62.2% and 58.9% of all stations, respectively. Through the abrupt change test and moving t-test, a significant abrupt point was found in 1995 for PET of Southwestern China (p<0.05). Among the 90 stations, abrupt points of 76 stations concentrated in the 1980s. In additional, 15 stations had no abrupt points which mainly distributed in the eastern margin of the Tibetan Plateau. On the whole, PET in Southwestern China increased slightly from 1962 to 2013. However, some regions appeared an opposite trend. The abrupt test also showed the same pattern. Complex terrain environment and climate characteristics are the main factors reflecting the unique feature of hydrometeorology changes in Southwestern China.