With the accelerating process of urbanization, the problem of environmental protection is becoming more and more prominent. Strengthening the construction of ecological civilization has increasingly become the focus of urban development. Therefore, it is particularly important for rapid monitoring of changes in urban ecological environment. Landsat TM/OLI remote sensing images of 1995, 2005 and 2015 were chosen as the main source of data. Four ecological factors were calculated as evaluation indicators, namely greenness, wetness, dryness, and heat. Principal component analysis was used to derive the remote sensing ecological index (RSEI). The ecological changes in Wanjiang city belt in recent 20 years were analyzed objectively, rapidly and quantitatively. The results show that the changes of ecological environment quality in Wanjiang city belt in 1995-2015 years are “down then up”, with an overall rising trend. The RSEI dropped from 0.710 in 1995 to 0.683 in 2005, and then rose to 0.728 in 2015 with a total increase of 2.54%. During 1995-2015, the proportion of ecologically deteriorated areas decreased from 20.03% to 14.65%, with a decrease of 26.86%. While the proportion of ecologically improved areas increased from 21.87% to 29.39%, with an increase of 34.39%. The ecologically deteriorated areas are mainly concentrated in the expanding cities and regions along the Yangtze River. The areas with improved ecological environment mainly concentrate on the areas with vegetation cover, environmental regulation and greening effect. Overall, urban ecological quality is most closely related to vegetation cover (NDVI) and impervious building area (NDBSI). With the development of urban expansion, we should strengthen the construction of ecological civilization, pay attention to environmental protection, increase the afforested area and realize the sustainable development of the city.

Key words：the Wanjiang City Belt; RSEI index; urban ecology; change detection; principal component analysis

Based on Weather Research and Forecast system mesoscale model (WRF V3.7.1 version), a case of Southwest vortex (SWV) rainstorm process during August 16-19, 2015 was simulated with six different Planetary Boundary Layer (PBL) parameterization schemes (YSU, MYJ, ACM2, MYNN2.5, BouLac, QNSE), and the effects of different PBL schemes on the characteristics of southwest vortex, precipitation and boundary layer physical field are analyzed and compared. The results showed that six PBL schemes have obvious influence on simulating precipitation, moving path and intensity of SWV. The ACM2 can preferably reflect the change of track of SWV and the center position, intensity, and dispersibility of the precipitation. Different PBL schemes made significant differences in simulating geopotential height and wind, relative vorticity, vertical velocity and equivalent potential temperature field. Compared with other schemes, the positive vorticity of SWV simulated by YSU and QNSE can extend from the lower troposphere to 200 hPa, and the result of ACM2 was closer to the facts than others. Six PBL schemes performed better in the PBL height, surface sensible heat and latent heat fluxes, which the diurnal change is evident. Among these schemes, the QNSE simulated larger PBL height and surface heat flux, which was probably caused by more detailed physical processes such as the interaction between internal wave and turbulence, while the ACM2 made ones smaller. It can be seen that different PBL schemes in WRF model have great influence on the simulation of different physical quantity field of the SWV rainstorm process, choosing the appropriate PBL scheme can improve the forecasting accuracy of the SWV weather process.

Key words：parameterization scheme; southwest vortex; precipitation; boundary layer structure; numerical simulation

This paper established a Human Settlement Environment Index（HEI）evaluation system, which included terrain, land, vegetation, climate, hydrology and stony desertification. A 250 m×250 m grid was taken as basic unit based on the Geographic Information System (GIS) and Remote Sensing (RS). The natural suitability characteristics and spatial difference of human settlement environment in Central Guizhou were analyzed using the HEI model. The results showed that: (1) the HEI of Central Guizhou ranged from 14.16 to 88.97 with the average value of 50.02. The natural suitability increased from northwest to north, east, south and from middle mountain area to low mountain, river valley and slotdam region. Relief amplitude was the main restriction to spatial distribution of natural suitability; (2) The moderate suitable area was 17 080.38 km2, accounting for 31.76% of the total area. The low suitable area, comparatively suitable area, unsuitable area and optimum suitable area accounted for 25.16%, 23.13%, 10.19% and 9.76%, respectively; (3) The optimum suitable residential areas were mainly distributed in the centraleastern region of low relief amplitude, high vegetation coverage, moderate altitude, abundant rainfall, and rich surface water resources, while the unsuitable areas were located in Qixingguan district, Dafang county and Zhijin county of Bijie city, where the average altitude was more than 1700 m, the rest was distributed sporadically in the study area.

Key words：GIS; human settlement; natural suitability; central Guizhou Province

In order to study the eutrophication driven factors and its status in Hanfeng Lake，exploratory data analysis were applied to analyze the relationship between hydrodynamic conditions and environmental factors, the principal component of water quality, the related environmental factors of entropy weight and NHI(Nutritional Health Index). The results of regression analysis show that a positive correlation between water level and transparency, and negative correlations among flow discharge and DO, Chla, CODMn, NH+4－Nand DTP; three principal component were extracted by Principal Component Analysis(PCA),which represneted nutrients, organic pollutants and algaes, respectively. The entropy weights of DO, TN, TP show that the eutrophication status of Hanfeng lake were subjected to aerobic organic pollutants, nitrogen and phosphorus.The nutritional health index show that S1 >S3> S6(the center of lake) >S7(the tail of lake) > S5(the head of lake）> S4 >S2. In general, the eutrophication level of Hanfeng lake was ranged from mesotropher to light eutropher, with higher nutrient levels in South river, and higher nutrient in the center of lake when campare to the head and the tail of lake. In conclusion, reducing the input of organic pollutants and nutrient, and improving the hydrodynamic conditions of the local area are able to efficiently inhibit the growth of algae, which favors to the control of eutrophication.

Key words：exploratory data analysis; Hanfeng lake; eutrophication; driven factors; hydrodynamic conditions; principal component; entropy weight; nutritional health index

Based on the theory of system theory, environmental value theory and humanland relationship theory, this paper constructs the “pressurestateresponse” evaluation model of ecological security of reservoirtype tourism destination, and uses fuzzy set pair analysis to quantitatively analyze the ecological security level of Tianmu Lake in Liyang City in 2005 and 2015，and its spatial and temporal differentiation characteristics, and through information entropy to explore the key factors of ecological security changes. The results show that the ecological security status of the tourism priority development area in the downstream of Shahe Reservoir is poor, and the ecological security situation in the surrounding area of Daxi Reservoir is better. On the time scale, the ecological security level of all regions has been improved, and the ecological security level of the tourism priority development zone has a large positive fluctuation. The study shows that tourism development factors, population factors and environmental response policy factors are the key factors to determine the ecological safety of Tianmu Lake.

Key words：reservoirtype tourist destination; ecological security; spatial and temporal differentiation; influencing factors; Tianmu Lake

Monitoring soil moisture by remote sensing plays a significant role in the dynamic characterization and management of surface heat balance, water evapotranspiration and soil moisture in agricultural production. In order to verify the applicability of GF1 data in the rapid acquisition of agricultural parameters in Jianghan Plain, this study simulated, compared and validated the effectiveness of soil moisture inversion. All of the data were Sampled in the vegetation area of Qianjiang City on March 8, 2017, GF1 WFV image and measured soil moisture data were used to retrieve the Perpendicular Drought Index(PDI), the Modified Perpendicular Drought Index(MPDI) and the Vegetation Adjusted Perpendicular Drought Index(VAPDI). The results showed as follows: firstly, determinate coefficients of correlation analysis on PDI, MPDI, VAPDI and measured soil moisture were 0.649, 0.802 and 0.821 respectively. All of the models met the accuracy requirements of inversion in the accuracy evaluation of soil moisture. Both of them indicated that using GF1 WFV image is feasible for soil moisture inversion in large scale in Jianghan Plain. Secondly, in the area of moderate vegetation coverage, MPDI and VAPDI had higher inversion accuracy than PDI. To a certain extent, they overcome the influence of mixed pixels on soil moisture spectral information. While in the area of high vegetation coverage, VAPDI modified by Perpendicular Vegetation Index(PVI) were not susceptible to vegetation saturation and thus had higher inversion accuracy. Thirdly, spatial heterogeneity of soil moisture retrieved by three models were similar. However, MPDI and VAPDI were more sensitive to the change of soil moisture, which reflected the actual soil moisture level that covered by different vegetation. The results can provide practical reference for dynamic monitoring of surface soil moisture in large scale in Jianghan Plain.

Key words：GF1; soil moisture; PDI; MPDI; VAPDI; Jianghan Plain

In order to clarify the influence of different terrain on the stable isotope of precipitation in the southwest and the geographical boundary of each water vapor mass, a total of 10 research sites in Sichuan Basin, YunnanGuizhou Plateau, the eastern of QinghaiTibet Plateau and Hengduan Mountains were selected as the study area, analyzing the spatiotemporal variations of δD and δ18O in precipitation in southwest China and initially establishing three regional meteoric water line. Relations between δ18O in precipitation and air temperature, amount and moisture sources were discussed, and HYSPLIT4.9 model was used to analyze and trace water source and migration path of precipitation events in summer and winter half year. The results show that there are significant elevation effects of precipitation stable isotopes in the southwest region, that as δ18O=-0.002 8H-3.93 and R=0.89, values of δ18O and δD in the precipitation are gradually depleted from the Sichuan Basin, the YunnanGuizhou Plateau, the eastern part of the QinghaiTibet Plateau and the Hengduan Mountains, and that the seasonal variation characteristics of the winter half year are positive on a whole, while those of the summer half year are overall negative. In addition to Kunming and Chengdu area, the value of d in the southwest region shows the trend of being low in summer and being high in winter, which is in line with the characteristics of the region influenced by monsoon precipitation in China. Compared with the global meteoric water line(GMWL), slopes and intercepts of regional atmospheric precipitation lines(LMWL) in the Sichuan Basin, the eastern QinghaiTibet Plateau and the Hengduan Mountains are apparently smaller, while those in the YunnanGuizhou Plateau are larger, which is mainly relative with temperature of water vapor condensation and evaporation, water vapor sources and transmission ways. Temperature effect and precipitation effect are different in different regions—there is no temperature effect in the Sichuan Basin, the YunnanGuizhou Plateau, the eastern QinghaiXizang Plateau and the Hengduan Mountains, but a remarkable precipitation effect. There are also differences in dominant water vapor mass in different regions of Southwest China. Based on the preliminary analysis of the dominant water vapor during winter and summer monsoon season in different regions, conclusions can be draw that the areas affected by single water vapor mass are mainly distributed in the southwest and northeast, while the regions influenced by multiple water vapor mass are primarily distributed in the northeast and southeast, that the GuiyangAnshun line is on the border of the Western Pacific water vapor mass and the Bay of Bengal water vapor mass, and that ChengduWolongHuanglong line is on the border of the Western Pacific water vapor mass and the Westerly water vapor.

Key words：atmospheric precipitation; stable isotope; water vapor source; different terrain; southwest region

In view of the divergences and regional adaptability between different data products of AVHRR NDVI and MODIS NDVI datasets, the NDVI Collection 5(C5) and Collection 6(C6) products of MODIS Terra/Aqua and the GIMMS NDVI3g products in AVHRR NDVI from 2003 to 2013 were used for comparison and analysis in typical regions of HanJiang River Basin. The consistency of the data in the seasonal fluctuation was evaluated by the association index(IOAs). The Mann Kendall test was used to analyze the longterm trend of different data products. The results show that the correlation between different versions of the same satellite is relatively high in seasonal changes. In the interannual changes, GIMMS products can only detect partial NDVI trends which MODIS products can detect. In the area where the surface coverage is relatively heterogeneous, the detection rate of GIMMS products is low. NDVI C5 product of MODIS Terra was affected by sensor degradation, showing a relatively high reduction trend.

Key words：GIMMS NDVI; MODIS NDVI; Mann Kendall Test; trend analysis

Using the daily meteorological data from 1961 to 2010 in the middle and lower Yangtze River reaches, this paper analyzed decadal variations of the spring waterlogging disaster and the risk of winter wheat loss suffered from spring waterlogging disaster by monitoring index model and assessment model. The results showed that winter wheat suffering from spring waterlogging disaster occurred frequently in the south regions of Yangtze River reaches, causing reduction in output for more than 30% years. And also, the decadal variations of risk of winter wheat loss due to spring waterlogging disaster are significant, with the features that highest risk ranges are maximal in the 1960s, which followed by the 1970s and 1990s, and the highrisk areas are the smallest in the 2000s, with scattering features in Jiangnan regions. At the 30 a scale, the regions of high risk area of spring waterlogging disaster are gradually decreasing, and the lower risk areas are increasing.
Key words：in middle and lower Yangtze River reaches; spring waterlogging disaster of wheat; the loss risk; decadal variation

Soil available microelement contents are essential mineral nutrients for plant growth, and important parts of organic nutrient and soil fertility, they play important roles in growth and development of plants, community composition of the vegetation and structure and function of the ecosystem as well. The study on spatial variation characteristics of five soil available microelement including B, Fe, Cu, Zn and Mn as well as their influencing factors in the terrestrial ecosystem at a provincial scale is the fundamental basis of the study on regulate the circulation of trace elements, improve the yield and quality of plants, and formulate the formula card for accurate fertilization. Based on the data of the 16 582 soil samples collected in the topsoil layer (0~20 cm) of the farmlands during implementation of the project of soiltestbased formulated fertilization in Jiangxi Province in 2012, using pearson correlation analysis, spearman correlation analysis, partial correlation analysis, combined with oneway variance analysis and geostatistics, analysing the spatial variation characteristics of soil available microelement contents and their influencing factors. Results show as follows: ① Soil available B, Fe, Cu, Zn and Mn were reached the above moderate level, B showed strong variability, other soil available microelement showed moderate variability. ② In respect of the spatial structure, soil available B, Fe, Cu, Zn and Mn of the nuggest/still ratio were 15.68%, 87.63%, 12.09%, 25.27% and 77.98%, which show B and Cu have strong spatial correlation, Zn showed moderate spatial correlation and Fe and Mn indicated weak spatial correlation. In respect of the spatial distribution, soil available B content showed a spatial distribution tendency with lower in two sides and higher in middle, Cu, Zn and Mn displayed a similar distribution tendency seen smooth and there is no discernible distribution rule of Mn. ③ Pearson correlation analysis and partial correlation analysis showed that there is a definite coupling relationship between five soil available microelements but there is no direct contact. Spearman correlation analysis and oneway variance analysis results showed that topographic factors, soil chemical factors(including pH, organic matter and total nitrogen), soilforming factor and stochastic factors had significant impacts on the spatial variability of five soil available microelements(P<0.05). The results can provide a reliable reference for the formulation of soil testing formula fertilizer card, the utilization and management of cultivated land resources and the planting of good quality and high yield in Jiangxi Province.

Key words：Jiangxi Province; soil available microelement; spatial variability; correlation analysis; partial correlation analysis; influencing factors