Green development is an important factor for the tourism sustainability.The green development efficiencyof tourism industry is a significant standard for the implementation of green developmentin tourism industry. This study analyzed the spatial-temporal evolution characteristics and the evolution trend of green development efficiency in China’s urban tourism industry from 2010 to 2019. Simultaneously, the Dagum Gini coefficient was employed to analyze the spatial differences and the sources of green development efficiency in China’s urban tourism industry. Finally, the spatial Durbin model was used to analyze the spatial spillover effect of the influencing factors. The following results were found: (1) The green development efficiency of China’s urban tourism industry during the study period demonstrated a fluctuating trend, “W” development trend, and a significant spatial agglomeration feature. (2) There was a phenomenon of “club convergence” in the green development efficiency of the urban tourism industry, which indicated the challenges in achieving the leapfrog development in the short run. The retrogression risk of high-efficiency cities was higher than that of other grades, mainly moving down toward higher efficiency. (3) The overall Gini coefficient of the green development efficiency decreased slightly, but it exhibited strong fluctuations, and the stage characteristics were obvious. Before 2013, the spatial difference showed a gradually expanding trend, followed by a relatively significant decreasing trend from 2014 to 2017, and finally a slightly expanding trend. Regional differences contributed significantly to the overall differences in green development efficiency. (4) The specialization level of tourism industry and traffic accessibility had a positive spillover effect, while the economic development level had a negative spillover effect. Finally, based on the conclusions, the corresponding suggestions were put forward, which were of great significance in promoting the high-quality development of the urban tourism industry in China.

Economic resilience refers to the ability of cities and regions to quickly absorb, recover and maintain normal economic operation when they suffer from shocks. This is crucial towards the realization of high-quality regional development strategies. Based on the impact cycle, this paper divided regional economic resilience into long-cycle and short-cycle economic resilience, and measured the level of long-cycle economic resilience of the urban agglomeration in the middle reaches of the Yangtze River. The spatio-temporal evolution characteristics of economic resilience were also analyzed in terms of temporal and spatial evolution pattern. The corresponding influencing factors were further identified. The results showed that: （1) There were significant spatial differences in the economic resilience in the study area.(2）The main influencing factors of short-cycle economic resilience varied with the impact type and development stage. The government governance ability had a positive and lasting effect on economic resilience.(3)The influencing factors of long-cycle economic resilience demonstrated a certain stability and regularity. The innovation ability and labor status were the core factors affecting economic resilience. The factors such as economic development foundation, foreign trade and government governance ability also played an important role in regional economic resilience. These outcomes may provide a reference for grasping the law of economic resilience development and for improving the level of regional economic resilience.

Balanced economic development is an important connotation for measuring the high-quality development of regional economies, which is also a requirement for the development of the new normal in low economic development provinces such as Guizhou. This paper constructed the county economic density evaluation index system for 2000, 2010 and 2020. The entropy weight TOPSIS method, kernel density estimation method, spatial autocorrelation method and spatial panel model were applied to measure the comprehensive score of economic density. The spatio-temporal characteristics and influencing factors were also explored. The results showed that: (1) the economic density of Guizhou's counties generally increased over time. The nuclear density curve was dominated by multiple peaks, with the main peak increasing over time and a small contraction in width from 2000-2020. (2) Spatially, the centers of high economic density were shrinking, with positive growth counties dominating in 2000-2010 and negative growth counties dominating in 2010-2020; In the global spatial autocorrelation, the degree of spatial agglomeration of economic density increased and then decreased. The local spatial autocorrelation was dominated by the agglomeration of the high-high and the low-low modes. (3) There was a significant spatially endogenous interaction of economic density, where each 1% increase in economic density in the neighboring counties would promote a 0.2% increase in local economic density. (4) Regarding the affecting factors, talent endowment and medical beds had a positive effect on economic density, and other factors had a negative effect. The strength of the direct effect is ranked as follows: talent endowment > precipitation #> population aging #> ethnic structure #> vegetation cover #> medical beds (# indicates a negative effect). The size of spatial spillover effect contribution was ranked as follows: talent endowment > population aging #> precipitation #> ethnic structure #> medical beds. Therefore, Guizhou should focus on the regional balance of economic development, and make up for the shortcomings of economic development in ethnic counties while continuing to attract talents and improve social welfare conditions.

Guided by the principle of prioritizing ecological protection, this study developed an evaluation system of green development performance in key eco-function areas by selecting 23 indicators from environmental protection and utilization, the green development of economy and social harmony and progress. Based on the evaluation system, the green development performance (2000-2020) in the Three Gorges Reservoir Area was evaluated by combining entropy weighting method and expert scoring method. Also, this study explored the multi-dimensional space-time effects and analyzed the development performance of the environmental system, economic system and social system in the Three Gorges Reservoir Area and their coupling coordination degree. It was found that the score of the green development performance in the Three Gorges Reservoir Area was between 0.3 and 0.5, which was not high in general but it was steadily increasing with time. Environmental protection and utilization contributed the most to the green development performance, followed by the social harmony and progress. The green development performance in the belly section was the highest, followed by the tail and head section, It was found that the regional deviation was reducing. Regarding the spatial-temporal pattern, the green development performance featured a rising trend with seven regions in the lead, showing a positive spatial correlation but a loose spatial agglomeration. Although the coupling degree between the environmental, economic and social systems was high, the coupling coordination degree was limited and thus the complex ecosystem was in a low level of coordinated development.

Carbon sequestration service can directly fix CO₂ in the atmosphere through the photosynthesis of natural vegetation, and the balance of supply and demand is crucial for mitigating the trend of global warming. However, most of the current studies focused on the supply of carbon sequestration service, and few focused on regional carbon supply-demand balance. The Yangtze River Delta Ecological Greening Development Demonstration Area (Demonstration Area) is the first step and breakthrough to implement the integration development strategy in the Yangtze River Delta. It is also the key area to achieve the carbon peaking and carbon neutrality goals in the Yangtze River Delta.Taking the Demonstration Area as a study area, this paper evaluated the supply of carbon sequestration service based on CASA model, and identified the demand of carbon sequestration service based on population density method. This paper also explored the supply, demand and supply-demand ratio of carbon sequestration service.The results showed that, in terms of supply, the spatial distribution of carbon sequestration service in different towns was relatively balanced from 2000 to 2020. The total carbon sequestration increased from 1.10×109 kg to 1.24×109 kg, with a fluctuating trend. In terms of demand, the demand for carbon sequestration service increased from 7.15×109 kg to 4.16×1010 kg from 2000 to 2020, an increase of nearly five times. The demand for carbon sequestration service in all towns showed an increasing trend. From 2000 to 2020, the carbon sequestration supply was difficult to meet its demand, and the supply-demand ratio continued to decline, indicating a tense relationship between supply and demand. Finally, based on the supply, demand and supply-demand ratio of carbon sequestration services, this study carried out carbon sequestration service zoning. This paper aimed to put forward targeted decision-making suggestions for the realization of carbon peaking and carbon neutrality goals in the Demonstration Area.

Widespread in the Yangtze River mainstream, wetlands of mid-channel bars and islands caused by seasonal inundation have important ecological effects such as protecting biodiversity and purifying the environment. These wetlands are regarded as important material basis for ensuring ecological security in the Yangtze River basin. The distribution and dynamics of wetlands in the Yangtze River basin and their ecological significance have received a lot of attention, while the wetlands of mid-channel bars and islands in the Yangtze River mainstream, an important component of Yangtae River basin wetland, has been less studied and reported. In this study, Google Earth high-resolution remote sensing images were used to visually interpret and extract the wetlands of mid-channel bars and islands, GIS methods were adopted to extract channel morphological parameters and correlation analysis as well as ordered logistic regression analysis were used to reveal the distribution of these wetlands. Also, the influence of channel morphology on the distribution of the wetlands was explored. The results were as follows. The spatial distribution of the wetlands demonstrated four sections, namely, Yibin-Zhongxian section, where only small and medium-sized wetlands were distributed; Zhongxian-Yichang section, where no wetlands were distributed; Yichang-Jiujiang section, where small and medium-sized wetlands dominated; and Jiujiang-Yangtze River Estuary section, where wetlands of all area level were widely developed. In the last section, the small and medium-sized wetlands were denser than in the immediately upstream Yichang-Jiujiang section, while the large-sized wetlands were almost the same as in the Yichang-Jiujiang section. The number of small-sized wetlands in the study area was larger than that of large-sized wetlands. Small-sized wetlands were less sensitive to channel morphology than the large-sized wetlands. The area of the wetlands had a significant positive relationship with channel width and the difference in channel width, while the area had a significant negative relationship with difference in shoreline length. This implied that a wider, straighter, and more symmetrical river channel was conducive to the development of large wetlands of mid-channel bar.

The riparian areas of lakes and reservoirs with diverse land use types have a large fluctuation of carbon sequestration potential affected by land management strategies. An accurate estimation of carbon storage and sequestration potential is a critical step for carbon neutrality practices. The carbon-storage estimation has been widely implemented in forest and farm land ecosystem, but has been rarely investigated for the riparian areas of lakes and reservoirs. To quantify the carbon storage of the riparian areas of lakes and reservoirs, this study selected the riparian areas of Shahe Reservoir (surface water area of 12 km2 and mean water depth of 7 m) in a mountain area of eastern China as the study area. A raster-based model was developed to estimate carbon storage based on the InVEST model, widely used in case studies across the world. The estimated results were comparable with those from previous publications, implying the reasonability of the model. The developed model was then used to investigate the response of carbon storage and sequestration potential to land management strategies, such as optimization of cultivation and fertilization, and mixed planting. Our investigation results revealed that the riparian areas of Shahe Reservoir had a total carbon storage of 3.25×105 t (i.e., 9 961 t/km2) in 2022. Forests, farmlands and tea lands contributed to 33.24%, 24.34% and 8.62% of the total carbon storage. Cultivation optimization had the largest potential in carbon sequestration (22 357 t). Our study demonstrated the significant advantage of the developed raster-based model in estimating carbon storage, and can be potentially used in other lakes and reservoirs via parameter measurements. However, the developed model also included considerable model uncertainties, which required significant efforts to minimize. For example, the parameter of carbon density was a critical and sensitive parameter in the developed model, but demonstrated a large variation among different land use types. Therefore, further work is needed to improve the accuracy of model input data.

It’s an objective fact that imbalanced land development opportunities induced by planning regulation, such as urban development and ecological protection, undoubtedly differentiate rural household income. However, there is a lack of quantitative measurement. Measuring and decomposing the impacts of land development opportunities on rural household income can support policies of territorial spatial planning to rectify the imbalanced regional development that may be caused by planning. The Sino-French Ecological New Town and Xiaosi Township in Caidian District of Wuhan City are typical areas for urban development and wetland protection, where we surveyed 573 rural households by random sampling in 2021. The impacts of land development opportunities on rural household income were examined by propensity score matching and mediation effect model. The results showed that, firstly, the non-agricultural development opportunities of land in urban development zones had a significantly positive impact on the total income, local wage income, and transfer income of rural household. The estimated ATT values were 0.112, 1.014, and 0.254, respectively. Urban development and its economic agglomeration increased the household non-farm employment. The promotion effect of land development opportunities on farmers’ wage income was more significant for high-quantity, and low-quality households. Secondly, the allocation of household labor force intermediated the effect of land non-agricultural development opportunities on household income. The mediating effect of the proportion of household workers was 0.116, which was significant at the 1% level. Thirdly, compared to the wetland reserve, the income gaps in the urban development zones were smaller. The main reason was that the land development opportunities promoted the wage income growth of low-income household, and the negative impact on farming income was lower than that of high-income household. It was suggested to establish a co-construction and sharing mechanism for transferring added land value of land development to ecological protection and agricultural farming areas, so as to realize the sharing of land value increments between restricted and unrestricted development zones.

Remote sensing technology provides great convenience for monitoring water quality of inland lakes. However, it is difficult to directly find the optical characteristics of certain optically inactive water quality parameters, such as Total Phosphorus (TP), Total Nitrogen (TN) and permanganate index (CODMn). In the complex biological optical environment of inland waters, it is usually hard to fit the measured water quality data with the remote sensing reflectance of such parameters using a simple regression model. Moreover, when the size of measured water quality data sample is small, traditional machine learning methods are prone to under fitting, resulting a low accuracy of water quality inversion results. To address these problems, this paper proposed a dot product attention model for estimating water quality parameters. The model was constructed using 58 measured water quality data and the corresponding Sentinel-2 remote sensing data, in Daye Lake. To verify the accuracy and priority of the proposed model, this paper compared the results with the water quality inversion results of statistical regression model and multi-layer perceptron model under the same measured water quality data sample and image data. Results showed that the accuracy of the inversion results based on the dot product attention model were the best, with the determination coefficients R2 of TP, TN and CODMn of 0.83, 0.89 and 0.80, respectively. The proposed model was also employed to estimate TP, TN and CODMn in Daye Lake from 2018-2021. These results help to explore the spatial and temporal variation characteristics of the water quality parameter concentrations in Daye Lake in the past four years and assess  the water pollution situation in Daye Lake. This research is expected to provide important data support for the water environment management of Daye Lake.

This paper explored the spatio-temporal evolution law and the driving factors of ecosystem services’ coupling coordination of supply and demand in Wuling Mountains area, in order to promote the sustainable development of regional society, economy and ecological environment. In this study, quantitative analysis was conducted on the supply and demand of ecosystem services in the region from 2001 to 2019, based on the market value method, the coupling and coordination degree model, and the geographically weighted regression model. The effects of multiple factors on the coupling and coordination degree were also examined. The results showed that: (1) The ESV increased by 3 billion yuan during the study period, reaching 369.697 billion yuan in 2019. (2) The ecosystem services’ spatial distribution of coupling degree between supply and demand and coupling coordination degree in this region was relatively stable. The coupling degree was dominated by intermediate coupling degree, and the coupling coordination degree was mostly in the state of weak coordination degree. (3) NDVI, the ecological quality index, and the local fiscal general budget expenditure had a positive driving relationship with the supply-demand coupling of ecosystem services, while NPP, precipitation, and GDP had a negative driving relationship. The ecosystem services’ coupling coordination between supply and demand in Wuling Mountains area presented a spatial pattern of high in the north and low in the south, which was affected by environmental and social factors. The results can assist in making scientific decisions for regional management.

With the rapid development of the digital economy, it is of great significance to explore the impacts and the mechanism of the digital economy on environmental pollution for promoting the high-quality development of the Yangtze River Economic Belt. Based on the panel data of 40 prefecture-level and above cities along the Yangtze River Economic Belt from 2011 to 2019, this paper explored the interaction mechanism of innovation level between digital economy and environmental pollution. The threshold effect model was used to analyze the nonlinear relationship and the effect range. The spatial spillover effect of digital economy using spatial Durbin model was further studied. The results showed that: (1) The digital economy had a significant inhibitory effect on local environmental pollution. This conclusion was still valid after a variety of robustness tests. (2) The innovation level was an important path for the digital economy to affect environmental pollution. When the innovation level exceeded the threshold value of 6.41, the impact coefficient of the digital economy on environmental pollution changed from -0.024 to -0.042, showing a marginal increasing pollution control effect. (3) While curbing local environmental pollution, the spatial spillover effect of the digital economy would exacerbate the pollution emissions in the surrounding areas. The expansion of the production scale might become the cause of increased pollution, and the inhibition effect was covered by the pollution growth, caused by the expansion of the production scale. Therefore, it is necessary to strengthen inter-regional collaborative governance to avoid dilution of the pollution control effect of the digital economy by unreasonable production scale.

Based on the global high-precision PM2.5 satellite inversion dataset from 2001 to 2020, in conjunction with spatial statistical analysis, geographic detector, and the geographically and temporally weighted regression(GTWR), this study examined the extent of influence and spatiotemporal heterogeneity of human socioeconomic and meteorological factors on PM2.5 in the Yangtze River Delta region. The findings were as follows:(1) The GTWR considered the temporal scale and demonstrated superior fitting performance compared to traditional global regression (OLS) and geographically weighted regression (GWR) models. (2)The geographical detector's q-value provided an accurate and quantitative explanation of the influence of each driving factor on PM2.5. The q-values of different factors exhibited fluctuating patterns across various time periods. Notably, the impact of population, road freight volume, electricity consumption, and temperature at the year-end maintained  a consistent upward trend.(3)The GTWR fitting results indicated that various factors had both positive and negative effects on PM2.5. Specifically, year-end population and temperature had significant positive effects, while road freight volume, electricity consumption, and relative humidity at the year-end had significant negative effects. Other factors demonstrated varying degrees of fluctuation. Moreover, the regional variation in regression coefficients suggested distinct spatial and temporal heterogeneity among the driving factors.

Nitrous oxide (N₂O) is the world’s third largest greenhouse gas after carbon dioxide (CO₂) and methane (CH₄) and is increasing year by year. The intensive development of agriculture and the advancement of urbanization in the Three Gorges reservoir area will also exacerbate N₂O emissions. In order to understand the emission of N₂O in the reservoir area and make suggestions for the low-carbon development.This study used the IPCC emission factor method and scenario analysis method to study the differences in N₂O spatio-temporal distribution and to explore the emission reduction potential in the Three Gorges Reservoir Area.The results showed: (1) N₂O emissions in the Three Gorges reservoir area remained at 14 700-16 200 t in 2006~2019. The overall emission trend was first higher and then decreased. The difference between 18 districts and counties in the reservoir area was significant (P<0.01), and the spatial distribution was random (annual average Moran I≈0 in the past 14 years). (2) Agricultural activities in the Three Gorges reservoir area were the main sources of N₂O, while fertilizer application and fecal emissions contributed the most to N₂O, accounting for 40.48% and 23.84%, respectively. By application of the STIRPAT model, it was found that among the driving factors of N₂O emissions, the urbanization rate had constraining effects in the Three Gorges reservoir area, and the promotion factors from small to large were the grain output, the number of rural employees, the value-added of the primary industry and the per capita GDP. (3) The N₂O emissions in the Three Gorges Reservoir Area in 2030 were predicted under three emission reduction scenarios. The forecast values were 15 500, 13 400 and 12 100 t, respectively.In view of the N₂O emissions and future predictions in the Three Gorges reservoir area, it was recommended that the amount of nitrogen fertilizer applied in farmland be controlled, and the management of livestock and poultry manure be strengthened, in the hinterland of the reservoir area. It was also suggested that a new agricultural mode be established. The circulation mechanism in the process of emission reduction should be further explored. Joint efforts should be considered in the future to control N₂O emissions.

Clarifying the typical nutrient components of silicon (Si), nitrogen (N) and phosphorus (P) in water and their temporal and spatial changes of ecological stoichiometry is helpful to explore the degree of eutrophication and the limiting state of phytoplankton nutrition. In this study, seven sampling sites were set up in Hanfeng Lake of the Three Gorges Reservoir. The temporal and spatial variation characteristics of concentrations of soluble silicate (DSi), soluble total nitrogen (DN), soluble total phosphorus (DP), chlorophyll a (Chl-a) and other indicators were measured via sampling from May 2020 to April 2021. The phytoplankton nutrient restriction status in water was assessed through the establishment of ecological stoichiometry relationship of Si, N and P.The results showed that the monthly average concentration of DSi was 18.80 mg/L with the lowest value in August and the highest in November. At the seasonal scale, this value was the lowest in summer and the highest in autumn. The monthly mean concentrations of DN and DP were 1.57 mg/L and 0.09 mg/L, respectively. The seasonal variations of DN and DP were similar, with high concentrations in winter and spring and low concentrations in summer and autumn. The monthly average concentration of Chl-a was 4.48 μg/L, with the highest in summer and the lowest in autumn, showing an opposite to the seasonal variation of DSi concentration, and a significant negative correlation. In space, the concentrations of DSi, DN and DP in Nanhe section were all higher than those in other sections. A small part of DSi might come from the release of sediment decomposition, and a large part of DSI was supplemented from land to water body via surface runoff. The mean value of the ratio of DSi/DN for the whole year was 6.47, with the lowest value in February and the highest in November. The ratio of DN/DP was the lowest in January and the highest in July, with an annual average of 47.76. The results indicated that the main limiting factor of phytoplankton growth in Hanfeng Lake was element P.

To investigate the aerobic and anaerobic microbial degradation of polycyclic aromatic hydrocarbons (PAHs) in riparian wetland soil, a microcosm incubation-based experiment combined with chemical analysis and 16S rRNA amplicon sequencing analysis was employed. The aerobic and anaerobic degradation rates of naphthalene, fluoranthene and pyrene and their key degradation microorganisms in a wetland soil sample of the JialingRiver, as well as the effects of different electron receptors on the microbial degradation of PAHs under anaerobic conditions, were explored. The results showed that the dissipation rates of naphthalene, fluoranthene and pyrene were 70.6%, 61.5% and 41.41% under aerobic conditions after incubation for 35 days, respectively. Under anaerobic condition, the dissipation rates of naphthalene, fluoranthene and pyrene were 76.01%, 72.59% and 42.57%. The addition of NO3- significantly promoted the anaerobic degradation efficiency of all the three PAHs, whereas the addition of SO42-inhibited the PAHs degradation. The addition of ferrihydrite (Fe(Ⅲ)) stimulated the degradation of pyrene, whereas the addition of goethite (Fe (Ⅲ)) stimulated the degradation of fluoranthene.The results of quantitative analysis of functional genes showed that the abundance of phnAc and bssA significantly increased under aerobic andanerobic conditions after the addition of PAHs. The sequencing results showed that the main aerobic PAHs-degrading bacteria were MND1, Arenimonas, Mycobacterium and Burkholderiales, whereasthe dominant PAHs-degrading bacteria shifted to Geobacteraceae, Hydrogenophaga and Bacteroidetes_vadinHA17 under anaerobic condition. The potential PAHs-degrading bacteria communities were influenced by the addition of different electron acceptors.Lysobacter and Arenimonas were significantly stimulated by the addition of NO3-. These results showed that the microbial PAHs degradation in the riparian wetland soil was jointly driven by different aerobic and anaerobic PAHs-degrading bacteria. The nitrate or Fe(III)-dependent anaerobic microbial PAHs degradation may have important contributions to the removal of PAHs in riparian wetland soils.

Taking the upper and middle Yangtze River basins as the main study area, we reconstructed the extreme flood events over the past millennium, based on literature, flood inscriptions, and modern water level data. We analyzed the patterns and differences in the occurrence of flooding events during different periods. The following significant conclusions were reached: (1) Extreme flood events for 45 years were reconstructed up to the country's founding. The average occurrence frequency was 18a, with an uneven inter-annual distribution; (2) the reconstructed flood years were extended to 2002 using modern observed water level data. A complete flood chronology were obtained from 1153 to 2002,where the years 1954, 1981, and 1998 were added; (3) according to the analysis of flood frequency and climate conditions, the frequency of floods in the study area over the past millennium was variable, with an increasing trend over the last two centuries. The frequency and driving mechanism of the flood years varied among periods. The Medieval Warm Period and Little Ice Age were characterized by the differences in cooling and warming, monsoons, and rainfall zones resulting from climatic variability. In contrast, human activities primarily influenced the Modern Warm Period, and the frequency and intensity of flooding events generally increased with time.

Drought has serious impacts on agricultural production and ecological environment in China. Study on the causes of drought and drought monitoring technology is crucial for drought warning and mitigation. By considering the atmosphere-vegetation-soil interaction and its mutual feedback mechanism, an attempt to develop anIntegrated Remote Sensing Drought Monitoring Index (IRSDI) was made by a multiple linear regression method based on meteorological stations data and multi-source remote sensing data in Poyang Lake basin from 2000 to 2020. The drought conditions across Poyang Lake basin in both space and time were revealed by SEN trend method and center of gravity migration model. The land use data and nighttime light data were used to construct the human activities pressure index, which was further applied to quantitatively analyze human impacts on the drought pattern in Poyang Lake basin. The results indicated that: (1) The applicability of the IRSDI was well evaluated and validated by using traditional drought index and drought affected area in the statistical yearbook. The proposed IRSDI model was able to accurately and quantitatively monitor the actual drought situation, and to reflect the comprehensive information of both agricultural drought and meteorological droughts. (2) The droughts in Poyang Lake basin was characterized by high drought frequency in the south and low frequency in the north, more severe droughts in the west than in the east, wide spread of droughts, and higher occurring frequency of basin scale droughts. The whole basin showed a wetting trend in summer and autumn, while a drying trend in winter and spring. (3) The impacts of human activities on droughts in Poyang Lake basin showed obvious north-south differentiation characteristics. During the study period, the anthropogenic pressure index increased generally in Poyang Lake basin, and was significantly higher in the north than that in the south. Ecological protection and green development have been implemented in the northern part of Poyang Lake basin, and the anthropogenic pressure inhibited the degree of droughts. Oppositely, extensive socioeconomic development in the south has caused damage to the environment and indirectly aggravated regional droughts. The observed results from this study are of theoretical and practical value for understanding the temporal and spatial variations of droughts in Poyang Lake basin and for enhancing the ability of regional drought prevention and resistance.