Simulation of Morphological Development of Soil Cracks in Yuanmou Dry-hot Valley Region, Southwest China

Soil cracking is an important process influencing water and solutes transport in the Yuanmou Dry-hot Valley region of Southwest China. Studying the morphological development of soil cracks helps to further reveal the close relationship between the soil cracking process and water movement in such semi-arid regions. Here we report regular changes on surface morphology of soil cracks with decreasing water in four different soils (Typ-Ustic Ferrisols,Ver-Ustic Ferrisols,Tru-Ustic Vertisols and Typ-Ustic Vertisols) through simulation experiments. Our results indicate the following: 1) Different soils ultimately have different development degrees of soil cracks,according to their various values of crack area density. Soil cracks in Typ-Ustic Ferrisols can only develop to the feeble degree,while those in the other three soils are capable of developing into the intensive degree,and even into the extremely intensive degree. 2) Soil crack complexity,as expressed by the value of the area-weighted mean of crack fractal dimension (AWMFRAC),is found to continuously decrease as a whole through the whole cracking process in all the studied soils. 3) Soil crack connectivity shows a uniform trend in the studied soils,that is to say,connectivity gradually increases with soil crack development.

Evaluation of regional tourism competitiveness:a case study of southwest China

Evaluation of regional tourism competitiveness has been a hot issue of tourism geography and regional economics in recent years. This study introduces system theory and Professor Porter's National Diamond Model into constructing the evaluation index system of regional tourism competitiveness, which includes four decisive factors, namely production factor, market, industry and support competitiveness. And by comprehensive use of subjective and objective methods like Principal Component Analysis (PCA) and Analysis Hierarchy Process (AHP) the appraised values were calculated. At the same time, the method was applied to dynamic demonstration analysis of the tourism competitiveness of the provinces in Southwest China from 2001 to 2005. The result shows that their tourism comprehensive competitiveness has distinct differences. The comprehensive competitiveness of Sichuan and Yunnan are better, Chongqing and Guangxi are in the middle, and Guizhou and Tibet are weak. According to the competitiveness ranks in 2001-2005, comprehensive, production factor, industry and support competitiveness changed a little and market competitiveness changed a lot. This competitive pattern has been made mostly because natural resource conditions and economic development levels of the provinces are very different and are difficult to be changed in a short period.

Increasing Flash Floods in a Drying Climate over Southwest China

In a globally warming world, subtropical regions are generally expected to become drier while the tropics and mid-high latitudes become wetter. In line with this, Southwest China, close to 25°N, is expected to become increasingly prone to drought if annual mean precipitation decreases. However, despite this trend, changes in the temporal distribution of moisture supply might actually result in increased extreme rainfall in the region, whose climate is characterized by distinct dry and wet seasons. Using hourly and daily gauge observations, rainfall intensity changes since 1971 are exalnined for a network of 142 locations in the region. From the analysis, dry season changes are negligible but wet season changes exhibit a significantly strong downward trend [-2.4% （10 yr）^-1], particularly during the past 15 years [-17.7% （10 yr）^-1]. However, the intensity of events during the wettest of 5% hours appears to steadily increase during the whole period [1.4% （10 yr）^-1], tying in with government statistical reports of recent droughts and flooding. If the opposing trends are a consequence of a warming climate, it is reasonable to expect the contradictory trend to continue with an enhanced risk of flash flooding in coming decades in the region concerned.

Some evidences for earthquake occurrence in the shallow crust in some areas of North China and Southwest China

The parameters of hypocentral location are important fundamental data for the study of seismology and the earth interior physics; among them, the focal depth is a very important one but can hardly be measured with higher precision. With the increase of seismic stations in number, the heightening of observation quality and the improvement of determination method, such a situation has been changed much. In this paper, the results of hypocentral location and re-location by 7 small-aperture digital seismic station networks at Tangshan, Zhangbei and Huailai of Hebei Province, Datong of Shanxi Province and Jianchuan, Luquan and Yao'an of Yunnan Province are used. Using these results together with those of focal depth inversion by far-field data of some individual large shocks in corresponding areas and those re-determined by the Linfen telemetered seismic network of Shanxi Province, a comparison with the results of focal depth determination in the past earthquake catalogues is made. It is found out that the focal depths determined by the small-aperture seismic networks are basically distributed in the range from the earth surface to ten-odd kilometers underground. In contrast, the focal depths determined in the past are mostly distributed at the depth range from the earth surface to 30 km underground. Besides, there is a difference of 50% to 100% between the average values of the two cases, which is quite an obvious one. From the result of analysis, it is considered that the results determined by the small-aperture seismic networks may be closer to the reality of focal depths distribution. That is to say, earthquakes in the above-mentioned areas should be distributed in the shallow part of the crust. The causes that lead to the above situation are discussed preliminarily, and some suggestions and measures for improving the precision of focal depth determination are put forward.

Spatial differentiation pattern of interregional migration in ethnic minority areas of Yunnan Province, China

Interregional migration has broad and far-reaching impacts on regional urbanization process in ethnic minority areas of Southwest China.The previous literature of interregional migration paid less attention on the ethnic minority areas with fragile geographical feature and marginal socio-economic context in the developing world due to the dearth of reliable data.Based on the 2015 national 1%population sampling survey at the village/community scale,taking Yulong Naxi Autonomous County,Yunnan Province,China as the case study,this paper analyzed the spatial differentiation pattern.The results showed that:(1)migration in Yulong Naxi Autonomous County exhibited obvious spatial differentiation characteristics in terms of population aggregation,population loss,migration direction,and migration activity;(2)the overall spatial differentiation of migration exhibited a"layer+sector"pattern in Yulong Naxi Autonomous County:the first layer was active areas with net inflows(<20 km from the seat of the county government),the second layer was inactive areas(within 20–60 km of the seat of the county government),and the third layer was a mixed"layer+sector"zone(>60 km to the seat of the county government),comprised of inactive areas and active areas with net outflows;(3)the spatial differentiation pattern of migration was highly correlated with the regional contexts including the regional economic development,regional transportation accessibility and regional social development,while regional physical geographical factors had insignificant relationships with the migration pattern.

唐代中国西南边疆拓南、开南二城的建置考论

经过了天宝战争及随后的军事扩张,位于唐代中国西南边疆的南诏国在较短的时期先后建置了拓东、开南、镇西、宁北四个王国边境的重要治所城镇,其中开南城与拓南城的考释自元末以后已多现舛误,造成了史实混淆。事实上,唐代中国西南边疆的拓南城与开南城确为南诏国开拓建置的两座新城,而非“开南亦称拓南”,元末以后,“拓南”名号逐渐隐没于原地,同时被移置于“开南”地望,开始混用一起。厘清二城地望考释,不难发现拓南城的建置开拓了南诏国的西南辖境,开南城的建置开拓了南诏国的南境,从而把中原的“郡县制”文化辐射到了西南边境区域,客观上促进了区域内各民族的交往交流交融,奠定了唐代及后世中国西南边境、边界形成和发展的历史基础,为唐代中国西南边境区域各民族铸牢中华民族共同体意识做出了贡献。

“美丽中国中脊带”西南段可持续发展路径研究

东西部发展失衡问题是长期以来制约中国社会经济发展的结构性与全局性问题。在国家生态文明建设与乡村振兴战略实施背景下,建设“美丽中国中脊带”作为缩小东西部发展不平衡的战略抓手具有重要的现实意义。“中脊带”西南段是我国西部大开发战略与“一带一路”倡议的重要发展区域,然而当地有限的自然与社会承载能力与政策所带来的经济红利之间的矛盾严重阻碍西南段的发展,因此亟需探索西南段的可持续发展路径。采用耦合协调度模型(CCDM)对2010—2019年“中脊带”西南段245个县的经济—社会—环境三系统协调发展情况、空间聚集特征进行了探讨。结果表明:“中脊带”西南段整体协调发展态势向好,然而区域发展不平衡现象十分突出。热点主要集中于以成渝城市群为核心的东北部,该地区三大子系统同步发展现象突出;冷点则主要分布在西南部少数民族聚居地区,区域内大多数县的经济与社会系统滞后于环境系统发展。此外,研究还发现不同的行政区划、生态本底、经济发展状况与协调发展水平的差异存在一定的联系。

国际区域视野下边疆治理的区域主义形成与演进机制探析--以中国西南边疆为例

关于边疆治理的区域主义转向的学术讨论,部分研究从国际区域的视野阐释边疆治理的区域主义,强调拓展边疆治理的国际区域空间,但对边疆治理在国际区域层面的区域主义形成与演进机制解释不足。引入国际关系学科的区域主义理论对边疆治理进行解析,有助于深化国际区域视野下边疆治理的区域主义理论与实践研究。借助区域化理论框架,边疆治理在国际区域层面的区域主义形成与演进机制包括起源、功能性、社会化和影响四个阶段,并且以边界问题解决为前提,与国家层面的区域主义有区别及联系。以中国西南边疆为案例,国际区域视野下边疆治理的区域主义形成与演进蕴含边疆治理与国际区域治理协同演进的逻辑,展现中国与周边国家命运共同体构建的路径探索。

Using Statistical Learning Algorithms in Regional Landslide Susceptibility Zonation with Limited Landslide Field Data

Regional Landslide Susceptibility Zonation(LSZ) is always challenged by the available amount of field data, especially in southwestern China where large mountainous areas and limited field information coincide. Statistical learning algorithms are believed to be superior to traditional statistical algorithms for their data adaptability. The aim of the paper is to evaluate how statistical learning algorithms perform on regional LSZ with limited field data. The focus is on three statistical learning algorithms, Logistic Regression(LR), Artificial Neural Networks(ANN) and Support Vector Machine(SVM). Hanzhong city, a landslide prone area in southwestern China is taken as a study case. Nine environmental factors are selected as inputs. The accuracies of the resulting LSZ maps are evaluated through landslide density analysis(LDA), receiver operating characteristic(ROC) curves and Kappa index statistics. The dependence of the algorithm on the size of field samples is examined by varying the sizes of the training set. The SVM has proven to be the most accurate and the most stable algorithm at small training set sizes and on all known landslide sizes. The accuracy of SVM shows a steadilyincreasing trend and reaches a high level at a small size of the training set, while accuracies of LR and ANN algorithms show distinct fluctuations. The geomorphological interpretations confirm the strength of SVM on all landslide sizes. Our results show that the strengths of SVM in generalization capability and model robustness make it an appropriate and efficient tool for regional LSZ with limited landslide field samples.

Effectiveness analysis of the prediction of regional debris flow susceptibility in post-earthquake and drought site

Debris-flow disasters occurred frequently after the Mw 8.0 Wenchuan earthquake on 12 May 2008 in Sichuan Province, China. Based on historical accounts of debris-flow disaster events, it found that debris flow occurrence is closely related to the impact of earthquakes and droughts, because earthquakedrought activities can increase the loose solid materials, which can transform into debris flows under the effect of rainstorms. Based on the analysis of historical earthquake activity(frequency, magnitude and location), drought indexes and the trend of climate change(amount of rainfall), a prediction method was established, and the regional debris flow susceptibility was predicted. Furthermore, in a debris flow-susceptible site, effective warning and monitoring are essential not only from an economicpoint of view but are also considered as a frontline approach to alleviate hazards. The advantages of the prediction and early monitoring include(1) the acquired results being sent to the central government for policy making;(2) lives and property in mountainous areas can be protected, such as the 570 residents in the Aizi valley, who evacuated successfully before debris flows in 2012;(3) guiding the government to identify the areas of disasters and the preparation for disaster prevention and mitigation, such as predicting disasters in high-risk areas in the period 2012-2017, helping the government to recognize the development trend of disasters;(4) the quantitative prediction of regional debris-flow susceptibility, such as after the Wenchuan earthquake, can promote scientific and sustainable development and socioeconomic planning in earthquake-struck areas.

“减穴稳苗”田间配置对西南稻区水稻冠层结构和光能分布的影响

【目的】明确“减穴稳苗”田间配置对西南稻区杂交籼稻冠层结构和光能分布特征的影响,从而为“减穴稳苗”田间配置在西南稻区的推广应用提供理论和实践依据。【方法】在温江和汉源2个生态点设置田间试验,采用单因素随机区组设计,设常规密植田间配置(THDP,行穴距30.0 cm×12.0 cm,每穴1.5苗,单、双苗错穴移栽)和“减穴稳苗”田间配置(ISRH,行穴距30.0 cm×24.0 cm,每穴3苗)两种配置,研究了不同田间配置对水稻冠层结构、冠层光能分布以及光合特性的影响。【结果】(1)较常规密植,减穴稳苗显著提高了两生态点单穴茎蘖数,使抽穗期水稻上三叶的叶倾角下降了0.93%~3.97%,进而使单穴叶面积和冠层幅度显著增加80.39%和28.99%。(2)减穴稳苗改善了水稻冠层中下部通透性,使温江生态点冠层3~40 cm处的透光率提高了18.08%~42.55%,汉源生态点冠层3~100 cm处的透光率提高了5.49%~44.22%,进而使抽穗至成熟期冠层底部的日辐射量和光照度分别提高46.74%和11.54%~75.63%。(3)较常规密植,减穴稳苗有效提高了水稻上三叶的光合能力,剑叶、倒2叶和倒3叶的净光合速率分别提高了16.96%~30.33%、9.35%~16.62%和12.93%~32.76%。【结论】采用减穴稳苗田间配置可有效改善宜香优2115的冠层结构,使冠层中下部的透光率明显提高,进而增加冠层底部光能供给,显著提升水稻上三叶的净光合速率。

西南山区生态地质调查技术方法研究

生态地质调查以区域地质调查成果为基础,查明调查区生态地质现状和主要生态地质问题,研究生态环境与地质条件之间的联系,并开展生态地质综合评价。笔者利用在大凉山区和三峡库区生态地质调查的探索经验,总结了西南山区生态地质调查与评价思路和技术方法,主要取得以下认识:(1)地质条件是生态系统的物质基础和孕育环境,地质条件通过制约土壤、水文、地形地貌、动力作用、地质灾害等生态地质条件,而制约生态系统质量和生态环境发展差异。(2)西南山区成土母质主要是下伏基岩原地风化或风化后近距离迁移形成的,存在明显的岩石-土壤-植被物质传导链条,地质条件是制约该地区生态环境质量的重要因素。(3)对地质建造和地质构造等地质条件的分析和研究,是在该地区进行生态地质调查的基础。(4)提出了西南山区生态地质调查的目的任务、工作思路、工作内容、技术路线和主要技术方法。该成果可为西南山区开展生态地质调查提供借鉴案例,同时对生态地质学科的建设和全国生态地质调查方法体系的建立也具有一定支撑作用。

西南边疆参与澜湄合作:成就、问题与提升策略

澜湄合作是新时期中国与周边国家开展次区域合作最富有成效的机制之一。自澜湄合作启动以来,以云南和广西为代表的西南边疆省区与湄公河国家在政策沟通、设施联通、贸易畅通、资金融通、民心相通以及优先合作领域取得了丰硕的合作成果,但仍存在合作优势不突出、辐射带动能力不强、国际交通枢纽支撑力不足、合作保障体系尚不完善等问题。为此,西南边疆省区应聚焦下一个“金色五年”的六大重点合作方向,打造澜湄合作的地方品牌,同时应以“一带一路”倡议为统领,主动融入国家发展战略,推动澜湄合作与西部陆海新通道建设实现高效对接,深化澜湄区域互联互通与经济融合,并加强合作支撑体系建设,保障多领域务实合作。

西南石漠化区林下土壤养分特征及差异性

文章采用文献检索法收集20世纪90年代以来石漠化区植被修复和土壤研究相关论文,以全国二次土壤普查养分分级标准为基础,探讨林下土壤养分改良情况及土壤化学计量特征。结果表明:(1)中国西南石漠化区林下土壤总有机碳、全氮均值均高于全国二次土壤普查养分一等级,全磷处于二级范围,土壤养分改善效果明显,而全钾含量属于五级低钾区;(2)广西壮族自治区总有机碳和全氮均值为五省(区、市)第一,全磷和全钾位于二等级和四等级,土壤养分含量增加最明显;贵州省总有机碳、全氮高于一等级34%和37%,全磷值在二等级范围,全钾值位于第五等级,贵州省石漠化林下土壤养分改良明显;云南省总有机碳、全磷指标分别高于一等级9%、21%,全氮属于二等级,全钾属于五等级,土壤养分指标有不同程度提高;重庆市总有机碳高于一等级1.75%,全氮和全磷属于二等级,全钾为五省中最高且属于四级,土壤养分指标改良较其他三省慢;湖南省总有机碳指标为二等级,全氮、全磷、全钾值分别属于二等级、五等级、五等级,湖南省需加强石漠化治理的力度;(3)西南石漠化区土壤总有机碳和全氮指标呈正相关,植被生长亦受钾元素限制。其中,广西壮族自治区总有机碳、全氮和全磷存储快,土壤改良效益极其显著;贵州省土壤固碳能力高于全国平均值;云南省石漠化地区土壤钾元素偏低,影响植被生长;重庆市土壤中全钾含量高与总有机碳、全氮、全磷关系不大,氮元素成为限制植物生长的元素;湖南省植被生长需补充磷、钾元素。西南石漠化区植被生长应充分补充钾元素,除此之外,湖南、重庆需加强磷、氮元素的补充;云南、湖南、重庆应借鉴广西壮族自治区生态修复经验,加强石漠化生态治理并发挥效益。

Characteristics of the Regional Meteorological Drought Events in Southwest China During 1960–2010

An objective identifi cation technique for regional extreme events （OITREE） and the daily composite-drought index （CI） at 101 stations in Southwest China （including Sichuan, Yunnan, Guizhou, and Chongqing） are used to detect regional meteorological drought events between 1960 and 2010. Values of the parameters of the OITREE method are determined. A total of 87 drought events are identifi ed, including 9 extreme events. The 2009-2010 drought is the most serious in Southwest China during the past 50 years. The regional meteorological drought events during 1960-2010 generally last for 10-80 days, with the longest being 231 days. Droughts are more common from November to next April, and less common in the remaining months. Droughts occur more often and with greater intensity in Yunnan and southern Sichuan than in other parts of Southwest China. Strong （extreme and severe） regional meteorological drought events can be divided into fi ve types. The southern type has occurred most frequently, and Yunnan is the area most frequently stricken by extreme and severe drought events. The regional meteorological drought events in Southwest China have increased in both frequency and intensity over the study period, and the main reason appears to be a signifi cant decrease in precipitation over this region, but a simultaneous increase in temperature also contributes.

我国西南电网辖区电力需求侧响应现状及优化发展建议

深入开展电力需求侧响应,对川渝藏三省(市、区)“双碳”目标的实现和新型电力系统的建设具有重要意义。本文在评价三省(市、区)的工业、商业、居民生活、数字新基建等方面的需求侧响应资源情况、川渝两地以往开展的激励型、价格型需求响应手段机制的基础上,提出两地面临经济发展水平和电网设施建设存在较大制约、响应资源类型和实施机制单一等问题。最后结合地区特点,提出扩大需求侧响应资源、重点探索微电网需求侧响应建设、提升需求侧响应市场化程度、积极培育负荷聚合商,夯实技术标准能力建设等建议。

民国时期西南地区疫灾分布格局及与气温变化的关联性研究

基于《中国三千年疫灾史料汇编》中民国卷的全国疫灾史料,提取整理出西南地区各县域逐年疫灾发生的时间序列并进行空间分布可视化。结合英国东英吉利大学(University of East Anglia)气候研究中心(Climatic Research Unit,CRU)提供的逐月气温数据集CRU TS v.4.05,利用Mann-Kendall突变检验、Sen斜率、热点分析及相关分析等方法研究气温变化、疫灾事件以及两者之间的关联性。结果表明:(1)民国时期西南地区每年均有疫灾发生,共发生疫灾4170次,平均每年约发生110次;波及共计3256县次,平均每年约发生86县;民国后期疫灾程度严重,频次与县次均呈现波动上升趋势,具有同步性;(2)平均温度整体表现为波动上升,空间分布上自东南向西北方向逐级递减,绝大部分为逐年上升趋势;(3)疫灾频次与温度具有显著正相关,夏秋疫灾多发,冬季少发;空间上有75.16%的研究区疫灾累积年数与平均气温呈现正相关,说明高温环境有利于疫灾的流行。(4)气温突变和波动幅度对疫灾的发生具有显著的影响,气温波动幅度大时,疫灾发生较多。

古代西南山区聚落体系演化与乡村发展研究——以云龙县“盐马古道”沿线聚落为例

位于西南山区的大理州云龙县曾是云南集结性盐区之一,近两千年来盐业的盛衰兴废深刻影响了当地聚落体系的演化和乡村发展。然而,当前盐业产业面临衰退,聚落体系逐步消散分解,乡村亟需转型。本研究基于聚落地理学和“历史—地理唯物主义”理论,结合历史文献研究和田野调查资料,对汉代以来云龙县“盐马古道”沿线聚落体系的演化模式和动力机制进行全景式梳理,试图从中加深对于社会建构、经济产业、文化发展等乡村发展的理解,丰富古代西南山区聚落体系史的研究。研究发现,依托该地区独特的自然禀赋条件,通过盐业生产、管理、贸易和移民等因素促进聚落体系不断演化,产生独立松散、双核并进、主副联通、单核引领和分散失衡五种结构模式,并形成了“产业驱动型”的乡村发展路径。进一步地,本研究立足现实困境,在文化转向背景下提出“文化引领”的乡村转型发展思路,以盐业文化为主线重塑聚落体系,形成“层级化、多元化、网络化”发展格局,助力乡村振兴。

他者眼光:晚明宦游士人地记中的南方书写

晚明宦游士人地记不同于唐宋笔记中对岭南、西南地区蛮荒的强调,而是依托明代相对稳定的政治文化生态和明代宦游风气的新变,将南方作为游赏的对象。以往的研究者并没有细致关注明人笔记中的南方书写以及文人对江南、岭南、西南印象的差异。通过细读可知文本,“南方”不只是地理空间,而是兼具了文化意义。两广和云南在内的广大“南方”地区不再是“化外之地”,描写“南方”的地记作品展示出对地方风俗、人物、遗迹等历史文化面向的关注。个人撰写的游记和私人编撰的地方志全面展示了文人将“蛮地”纳入中原文化的企图,也透显出宦游士人基于“异乡人”身份的南方印象与华夷文化间的冲突和对话。

西南地区高校来华留学研究生教育提质增效发展策略

当前,西南地区高校来华留学研究生教育发展迅速,规模增长显著,质量不断提升。文章对2013—2018年西南地区五省高校留学研究生现状展开分析,发现其存在着在全国及全球高等教育中竞争力不强的问题。为培养更多符合国际经济发展需求的高质量人才,提升我国高校国际化发展水平及在国际教育领域的竞争力,文章提出了加快高等教育现代化、加强中外经济文化合作、强化社会发展环境国际化、加强校企合作、拓宽招生渠道、严格入学考核等具体策略。