Driving forces and their interactions of soil erosion in soil and water conservation regionalization at the county scale with a high cultivation rate

Soil erosion control based on county scale Soil and Water Conservation Regionalization(SWCR)is an essential component of China's ecological civilization construction.In SWCR,the quantitative analysis of the spatial heterogeneity and driving factors of soil erosion among different regions is still lacking.It is of great significance for soil erosion control to deeply examine the factors contributing to soil erosion(natural,land use,and socioeconomic factors)and their interaction at the county and regional levels.This study focused on a highly cultivated area,Hechuan District of Chongqing in the Sichuan Basin.The district(with 30 townships)was divided into four soil and water conservation regions(Ⅰ-Ⅳ)using principal component and hierarchical cluster analysis.The driving factors of soil erosion were identified using the geographical detector model.The results showed thatⅰ)the high cultivation rate was a prominent factor of soil erosion,and the sloping farmland accounted for 78.4%of the soil erosion in the study area;ⅱ)land use factors demonstrated the highest explanatory power in soil erosion,and the average interaction of land use factors explained 60.1%of soil erosion in the study area;ⅲ)the interaction between natural factors,socioeconomic factors,and land use factors greatly contributes to regional soil erosion through nonlinear-enhancement of double-factor enhancement.This study highlights the importance of giving special attention to the effects of land use factors on soil erosion at the county scale,particularly in mountainous and hilly areas with extensive sloping farmland and a high cultivation rate.

Runoff Modeling in Ungauged Catchments Using Machine Learning Algorithm-Based Model Parameters Regionalization Methodology

Model parameters estimation is a pivotal issue for runoff modeling in ungauged catchments.The nonlinear relationship between model parameters and catchment descriptors is a major obstacle for parameter regionalization,which is the most widely used approach.Runoff modeling was studied in 38 catchments located in the Yellow–Huai–Hai River Basin(YHHRB).The values of the Nash–Sutcliffe efficiency coefficient(NSE),coefficient of determination(R2),and percent bias(PBIAS)indicated the acceptable performance of the soil and water assessment tool(SWAT)model in the YHHRB.Nine descriptors belonging to the categories of climate,soil,vegetation,and topography were used to express the catchment characteristics related to the hydrological processes.The quantitative relationships between the parameters of the SWAT model and the catchment descriptors were analyzed by six regression-based models,including linear regression(LR)equations,support vector regression(SVR),random forest(RF),k-nearest neighbor(kNN),decision tree(DT),and radial basis function(RBF).Each of the 38 catchments was assumed to be an ungauged catchment in turn.Then,the parameters in each target catchment were estimated by the constructed regression models based on the remaining 37 donor catchments.Furthermore,the similaritybased regionalization scheme was used for comparison with the regression-based approach.The results indicated that the runoff with the highest accuracy was modeled by the SVR-based scheme in ungauged catchments.Compared with the traditional LR-based approach,the accuracy of the runoff modeling in ungauged catchments was improved by the machine learning algorithms because of the outstanding capability to deal with nonlinear relationships.The performances of different approaches were similar in humid regions,while the advantages of the machine learning techniques were more evident in arid regions.When the study area contained nested catchments,the best result was calculated with the similarity-based parameter regionalization scheme because of the high catchment density and short spatial distance.The new findings could improve flood forecasting and water resources planning in regions that lack observed data.

Climate Regionalization for Morchella esculenta Cultivation in the Western Sichuan Plateau Based on GIS

Based on the meteorological data and DEM data in the producing areas of Morchella esculenta in the western Sichuan plateau from 1991 to 2020, the biological characteristics of M. esculenta, as well as the survey of production in the planting area, the correlation between M. esculenta production and the climatic ecological conditions at an altitude of 1 200-3 000 m in the western Sichuan plateau was comprehensively analyzed by using the inverse distance weight method, analytic hierarchy process, climate risk assessment model and geographic information system(GIS), and restrictive or high impact climatic ecological factors were selected as the suitability zoning indicators to carry out the analysis of climatic ecological suitability and planting zoning. The results show that the climatic factors affecting M. esculenta cultivation in the western Sichuan plateau were mainly temperature, temperature difference between day and night, and humidity, and the main meteorological disaster was freezing disaster. Under the influence of vertical changes in temperature, topography and cold damage, the growing areas of M. esculenta in the western Sichuan plateau were mainly distributed in the Minjiang River basin and the river valley along the Dadu River basin at an altitude of 1 200-2 000 m, and were distributed in strips and branches along the rivers. The suitable areas were mainly distributed in Wenchuan, Lixian, Maoxian, Kangding, Jiulong and Luding counties(cities), which were the main producing areas of M. esculenta, but the area was small, accounting for only 3.5% of the study area;the sub-suitable areas were mainly distributed in some towns of Danba, Xiaojin, Wenchuan, Lixian, Maoxian, Heishui and Jiuzhaigou counties, accounting for 36.0% of the total area, and they were the main planting areas of M. esculenta.

Analyzing Population Density Disparity in China with GIS-automated Regionalization: The Hu Line Revisited

The famous ’Hu Line’, proposed by Hu Huanyong in 1935, divided China into two regions(southeast and northwest) of comparable area size but drastically different in population. However, the classic Hu Line was derived manually in absence of reliable census data and computational technologies of modern days. It has been subject to criticism of lack of scientific rigor and accuracy. This research uses a GIS-automated regionalization method, termed REDCAP(Regionalization with Dynamically Constrained Agglomerative Clustering and Partitioning), to reconstruct the demarcation line based on the 2010 county-level census data in China. The results show that the logarithmic transformation of population density is a better measure of attributive homogeneity in derived regions than density itself, and produces two regions of nearly identical area size and greater contrast in population. Specifically, the revised Hu Line by Hu Huanyong in 1990 had the southeast region with 94.4% of total population and 42.9% of total land, and our delineation line yields a southeast region with 97.4% population and 50.8% land. Therefore, the population density ratio of the two regions is 27.1 by our line, much higher than the ratio of 22.4 by the Hu Line, and thus outperforms the Hu Line in deriving regions of maximum density contrast with comparable area size. Furthermore, more regions are delineated to further advance our understanding of population distribution disparity in China.

Nature and theoretical foundation of ecoregionalization:a case study in China

The increasing relevance and importance of zoning regional biotic factors and environmental variables to scientists and management agencies are fully introduced. Comprehensive research into regional differentiation of ecosystems, nevertheless, remains comparatively neglected. A rounded eco-regionalization System in terms of regional ecosystem properties and distribution can supply powerful tools for rational and sustainable utilization of natural resources, solution of regional environmental problems, and conservation of biodiversity. In this paper, ideas on nature, theoretical foundation and methods available to eco-regionalization are presented Finally, a new ecoregionalization system of China based on specific principles of ecological division is prepared.

Wind speed change regionalization in China(1961-2012)

This research quantitatively recognized the wind speed change using wind speed trend and trend of wind speed variability from 1961 to 2012 and regionalized the wind speed change on a county-level basis.The mean wind speed observation data and linear fitting method were used.The findings suggested that level-I regionalization includes six zones according to wind speed trend value in different regions,viz.Northeast ChinaeNorth China substantial declining zone,EasteCentral China declining zone,Southeast China slightly declining zone,Southwest China very slightly declining zone,Northwest China declining zone,and QinghaieTibetan Plateau slightly declining zone.Level-II regionalization divides China into twelve regions based on trend of wind speed variability and the level-I regionalization results.

A preliminary study on the theory and method of comprehensiveregionalization of cryospheric services

As one of the five most important spheres affecting climate systems globally, the cryosphere not only exerts crucial impacts on natural environment, but also plays a key role in guaranteeing the goods and services provision of the oasis in the cold and arid regions. However, there is a lack of synthesized knowledge about the contributions and profitability on socio-economic aspects of the cryospheric services (CSs). To cope with this key and urgent sustainable development issues, this study constructs a comprehensive regionalization research system that integrates the natural and socio-economic aspects for cryospheric characteristics with emphasis on interdisciplinary approaches. Guided by the supply- demand equilibrium model and the service maximization model, the research system consists of establishing a classification system for CSs, identifying the spatial distribution pattern of CSs, and constructing the comprehensive regionalization of CSs, which finally divides the research area into relatively independent, complete, and organically linked CS units of multiple spatial levels. By setting up a bridge between the CSs with socio-economic needs, it has profound and practical significance and implications for implementing the sustainable utilization strategies and macroeconomic policymaking for global environmental protection.

Regionalization of wheat powdery mildew oversummering in China based on digital elevation

Blumeria graminis f. sp. tritici, the pathogen that causes wheat powdery mildew, is one of the most important diseases affecting wheat production in China, and the oversummering is the key stage of wheat powdery mildew epidemic. The more oversummering regionalization of wheat powdery mildew has played an important role in disease prediction, prevention and control. In this study, we analyzed the correlation between oversummering data of wheat powdery mildew and the meteorological factors over the past years, and determined that temperature was the key meteorological factor influencing oversummering of wheat powdery mildew. The average temperature at which wheat powdery mildew growth was terminated(26.2°C) was used as the threshold temperature to regionalize the oversummering range of wheat powdery mildew. This regionalization was done using the GIS ordinary kriging method combined with the Digital Elevation model(DEM) of China. The results showed that annual probability of oversummering region based on Model 26.2 were consistent with the actual survey of the more summer wheat powdery mildew. Wheat powdery mildew oversummering regions in China mainly cover mountainous or high-altitude areas, and these regions form a narrow north-south oversummering zone. Oversummering regions of wheat powdery mildew is mainly concentrated in the high-altitude wheat growing areas, including northern and southern Yunnan, northwestern Guizhou, northern and southern Sichuan, northern and southern Chongqing, eastern and southern Gansu, southeastern Ningxia, northern and southern Shaanxi, central Shanxi, western Hubei, western Henan, northern and western Hebei, western Liaoning, eastern Tibet, eastern Qinghai, western Xinjiang and other regions of China.

Ecological function regionalization of fluvial corridor landscapes and measures for ecological regeneration in the middle and lower reaches of the Tarim River, Xinjiang of China

The middle and lower reaches of the Tarim River are currently one of the main regions of ecological restoration in the arid areas of western China.Using the principles and method of landscape ecology,this study has chosen the fluvial corridor landscape in the middle and lower reaches of the Tarim River,and discusses the region's ecologically functional regionalization system and issues related to its practical classification.On this basis the corresponding regionalizing principles and standards were developed which were used to qualitatively divide the three main landscapes as the ecologically functional areas in the drainage basin.The paper has also analyzed the characteristic of the study areas,and has put forward the measures for its ecological restoration.

Notes on the key role of stenochoric endemic plants in the floristic regionalization of Yunnan

With the accumulation and accessibility of information about plant species,it is time to re-evaluate and further divide a global biodiversity hotspot region,Yunnan,located in southwestern China.In this study,we combined data on the distribution of 1010 stenochoric endemic seed plants,vegetation constitution,geological history and climate change,and used these to propose a new system of floristic regions.We identified 11 distinct floristic subregions and 84 floristic provinces within Yunnan.Our work confirmed some views emphasized by Wu Zhengyi that the stenochoric endemic species play a key role in defining floristic provinces;that stenochoric endemic plants with long collection and publication histories are more valuable;that greater attention should be paid to woody plants;and that for Yunnan,a border region,some trans-border distributed elements should be treated cautiously.

QUANTITATIVE EVALUATION AND REGIONALIZATION OF TOURISM RESOURCES IN GUANGXI

ＱＵＡＮＴＩＴＡＴＩＶＥＥＶＡＬＵＡＴＩＯＮＡＮＤＲＥＧＩＯＮＡＬＩＺＡＴＩＯＮＯＦＴＯＵＲＩＳＭＲＥＳＯＵＲＣＥＳＩＮＧＵＡＮＧＸＩＨａｏＧｅｚｏｎｇ（郝革宗）ＧａｎＹｏｎｇｐｉｎｇ（甘永萍）ＨｕＨａｉｃｈｉ（胡海驰）ＤｅｐａｒｔｍｅｎｔｏｆＧｅｏ...

SNOW HAZARD REGIONALIZATION IN CHINA

For the zoning of snow hazard in China, on the principles of (a) comprehensive analysis integrated with dominant factors, (b) multi-level division, and (c) serving the agriculture and stock-raising, transportation and communication, we first classified China into two large zones according to the situation of snow or no snow distribution. Secondly, based on the climate and landform, properties of snow cover and main features of snow hazard, the large zone of snow hazard can be classified into three second-level regions. In order to obviously reflect the difference of snow cover quantity and snow hazard type as well as hazardous degree, twenty subregions (third-level) of snow hazard are further divided in detail. In addition, the boundaries and the principal features of the differences between the various snow hazard regions are provided.

Regionalization of Rainfall Intensity-Duration-Frequency (IDF) Curves in Botswana

A regional analysis of design storms, defined as the expected rainfall intensity for given storm duration and return period, is conducted to determine storm Rainfall Intensity-Duration-Frequency (IDF) relationships. The ultimate purpose was to determine IDF curves for homogeneous regions identified in Botswana. Three homogeneous regions were identified based on topographic and rainfall characteristics which were constructed with the K-Means Clustering algorithm. Using the mean annual rainfall and the 24 hr annual maximum rainfall as an indicator of rainfall intensity for each homogeneous region, IDF curves and maps of rainfall intensities of 1 to 24 hr and above durations were produced. The Gamma and Lognormal probability distribution functions were able to provide estimates of rainfall depths for low and medium return periods (up to 100 years) in any location in each homogeneous region of Botswana.

Risk Regionalization of Drought for Flue-cured Tobacco Planting in Qujing City Based on GIS

The risk regionalization of drought for flue-cured tobacco planting in Qujing City was studied to provide reference for drawing on advantages and avoiding disadvantages in flue-cured tobacco planting,disaster reduction,and disaster relief services.According to the production practice of flue-cured tobacco and local climate analysis,the risk of disaster-causing factors,sensitivity of disaster-breeding environment,vulnerability of carriers,and disaster prevention and reduction capability were analyzed and evaluated quantitatively.Secondly,starting from the formation mechanism of drought,a risk assessment model of the meteorological disaster was established by GIS technology.Finally,the risk assessment and regionalization of drought in the critical periods for drought-stricken flue-cured tobacco (transplanting period,root extending stage and vigorous growth period) in Qujing City were carried out.The results showed that in Qujing City,the risk areas of drought for flue-cured tobacco planting were divided into five grades in the transplanting period and six grades in the root extending stage and vigorous growth period.

Meticulous Regionalization of Climate Suitability about Spring Potato Planting in Western Guizhou Based on GIS

[Objective] The study aimed to carry out the regionalization of climate suitability about spring potato planting in Western Guizhou on the basis of GIS technology. [Method] Based on the climatic data of 15 meteorological stations in Western Guizhou during the growing period of spring potato from March to August in 1978-2010, the regionalization indicators of climate suitability about spring potato planting were determined according to the correlation between climatic factors and meteorological yield of spring potato. Afterwards, on the basis of climitic data and corresponding basic geographical information like longitude, latitude, altitude, slope and aspect, the spatial analysis models of division indicators about spring potato planting in Western Guizhou were established by using GIS spatial overlay analysis and used to carry out the township-level regionalization of climate suitability about spring potato planting in Western Guizhou with 100 m×100 m grids. [Result] Based on the relationship between meteorological yield of spring potato and climatic factors in Western Guizhou from 1978 to 2010, eight climatic division indicators, including altitude, average temperature,>10 ℃ active accumulated temperature, precipitation and sunshine hours in the growth stage, average temperature in July, average temperature difference between day and night from July to August, and precipitation from May to July, were chosen for spring potato planting, and each indicator had three levels, namely the most suitable, suitable and sub-suitable. Meanwhile, Western Guizhou was grouped into three areas according to these indicators, including the most suitable area, suitable area and sub-suitable area, and their area accounted for 52%, 45% and 3% of total area of the whole province respectively. [Conclusion] The research could provide scientific references for the production layout and species selection of spring potato in Western Guizhou.

Regionalization of Precipitation Regimes in China

Precipitation regimes of China were mapped by using empirical orthogonal function (EOF) analysis with orthogonal rotation based on normalized monthly mean precipitation data at 400 stations from 1961 to 2006.The regional boundaries were defined with the maximum-loading approach.The results identified 13 consistent and contiguous precipitation regions with distinct regional variations in China that are expected to reflect dominant regional patterns focusing on seasonal and interannual precipitation variations.The precipitation regionalization is operationally useful for seasonal and interannual climate predictions.

Analysis and Regionalization of Climate Ecological Conditions for Blueberry in Nanchong City Based on GIS

By using the meteorological data,GIS data and blueberry production data of Nanchong and the surrounding areas in Nanchong from 1991 to 2022,the climate ecological suitability of blueberry was analyzed based on the growth habit of blueberry,and the restrictive and high-impact factors were selected as zoning indicators to carry out climate ecological zoning.The results show that Nanchong has a humid climate,and the annual average temperature in most parts is 15.0-17.8℃;the cold temperature duration in winter is more than 770 h,and the average maximum temperature in July is more than 30.0℃,so it is suitable for planting southern high-bush blueberry,rabbit-eye blueberry and a hybrid of northern and southern high-bush blueberry.Sunshine,high temperature in midsummer,daily temperature range at the fruiting stage and terrain slope are the main limiting or high-impact ecological factors of blueberry production in Nanchong,among which the adverse effect of insufficient sunshine is the largest.The meteorological disasters affecting blueberry production in Nanchong mainly include rainy weather,rainstorm and flood,high temperature and drought.High temperature and heavy heat damage in midsummer in areas at an altitude below 400 m have a great impact on the production of late-maturing blueberry.High temperature and summer drought are often accompanied in the southeast,which will aggravate the adverse effects.The suitable area of blueberry in Nanchong is mainly distributed in the shallow hilly area and the low-mountain deep hilly and gentle slope area at an altitude of 350-700 m.The less suitable area is mainly distributed in the flat dam area of shallow hill-valley at an altitude of below 350 m,the low-mountain area at an altitude of above 700 m,and other hilly areas with a slope of 15-30°.The unsuitable area is mainly distributed in hills with slope>30°,some sporadic shallow hills and flat dams at an altitude of below 300 m,river banks,water wetland buffer zones,etc.In order to make full use of the climate resources and the advantages of blueberry varieties,early-and medium-maturing southern high-bush varieties should be mainly planted in the low-altitude area below 400 m in Nanchong,and medium-and late-maturing varieties should be mainly planted in the medium-altitude area above 400 m.

REGIONAL DEVELOPMENT AND REGIONALIZATION:RETROSPECT OF CHINA’S HISTORICAL ENLIGHTENMENT

Chinese had noticed regional differences in ancient times and thus arouse the concept of regional sustainable development which was successfully applied to delta cultivation and civilzation.Over the long term of regional development and regional exchange, much experience therefore was accumulated based on coastal zones, toward both inner land and open ocean. Regionalization, a basic job Preceding sustainable development of a region, has also been carried out in China since ancient times.More important, Patterns of regionalization were retained, these presents serve as references even today. Reflections on China’s historical enlightenment can assist us in locating the breakthroughs in regional development in the 21st century: facing the oceans with the seaport cities as nucleuses.

Spatial Function Regionalization Based on an Ecological-economic Analysis in Wuxi City, China

As a result of rapid urbanization in China, urban sprawl has increased rapidly, and land-use regulation and smart urban growth are equally important. Spatial function regionalization can provide the scientific groundwork for the regulation of land use and protection. This paper probes the system of evaluation indices and applies the methods of spatial analysis and classification clustering to the calculation of the ecologically significant value and economically significant value in each evaluation unit. After use of a classification matrix integrated by the two significant values, city space can be divided into four functional types, namely, feasible development area, moderate development area, moderate conservation area and prohibited exploiting area, and these are the basis for spatial development and control.

Multi-scale regionalization based mining of spatio-temporal teleconnection patterns between anomalous sea and land climate events

Climate sequences can be applied to defining sensitive climate zones, and then the mining of spatio-temporal teleconnection patterns is useful for learning from the past and preparing for the future. However, scale-dependency in this kind of pattern is still not well handled by existing work. Therefore, in this study, the multi-scale regionalization is embedded into the spatio-temporal teleconnection pattern mining between anomalous sea and land climatic events. A modified scale-space clustering algorithm is first developed to group climate sequences into multi-scale climate zones. Then, scale variance analysis method is employed to identify climate zones at characteristic scales, indicating the main characteristics of geographical phenomena. Finally, by using the climate zones identified at characteristic scales, a time association rule mining algorithm based on sliding time windows is employed to discover spatio-temporal teleconnection patterns. Experiments on sea surface temperature, sea level pressure, land precipitation and land temperature datasets show that many patterns obtained by the multi-scale approach are coincident with prior knowledge, indicating that this method is effective and reasonable. In addition, some unknown teleconnection patterns discovered from the multi-scale approach can be further used to guide the prediction of land climate.