GIS research to address tensions in geography

The rise of Geographic Information Systems (GIS) technologies has been producing powerful tools for spatial data processing, management, analysis, modeling, and visualization. While supporting many tasks, GIS technologies have evoked new thinking and advanced intellectual inquiries in geography. Technological advances in other fields often stimulate new research questions and lead to revolutionary discoveries. The Hubble telescope revolutionizes our understanding of the universe, and 3D digital microscopes transform our knowledge of the coordination among biological, neurological, and physiological systems in living organisms. Can GIS claim similar revolutionary effects on geography? The answer is much up for debate. With GIS technologies, geographic studies can explore a broader extent across multiple scales in space and time and tackle problems through increasingly complex spatial statistics, visual analytics, computation, simulation, machine learning, and artificial intelligence. Both the Hubble telescope and 3D digital microscope were built based on scientific research that subserves the technological advances for inquiries into space and life systems. Likewise, GIScience research innovates GIS methods that enable novel geographic investigations and therefore contribute to geographic knowledge production. For the sake of simplicity, the term GIS used here represents both GIScience and GIS technologies. This essay attempts to clarify the intellectual contributions of GIS to geography on the following two questions: (1) What novel geographic thinking is driven by GIS? (2) How may GIS provoke new geographic inquiries and knowledge? Building on Nystuen's notion of four tensions that trigger geographic questions, the essay discusses how GIS innovations mediate historical tension, space‐time tension, dimensional tension and scale tensions.     

1990-2019年贡嘎山地区典型冰川表碛覆盖变化及其空间差异

表碛覆盖型冰川是中国西部较为常见的冰川类型。表碛层存在于大气—冰川冰界面,强烈影响大气圈与冰冻圈之间的热交换。表碛厚度的空间异质性可极大地改变冰川的消融率和物质平衡过程,进而影响冰川径流过程和下游水资源。基于Landsat TM/TIRS数据,运用能量平衡方程反演了贡嘎山地区冰川表碛厚度,研究了贡嘎山地区冰川在1990—2019年间表碛覆盖范围及厚度变化情况,同时对比了东西坡差异。结果表明：① 贡嘎山地区冰川表碛扩张总面积达43.824 km²。其中,海螺沟冰川扩张2.606 km²、磨子沟冰川1.959 km²、燕子沟冰川1.243 km²、大贡巴冰川0.896 km²、小贡巴冰川0.509 km²、南门关沟冰川2.264 km²,年均扩张率分别为3.2%、11.1%、1.5%、0.9%、1.0%和6.5%;② 海螺沟冰川、磨子沟冰川、燕子沟冰川、大贡巴冰川、小贡巴冰川、南门关沟冰川表碛平均增厚分别为5.2 cm、3.1 cm、3.7 cm、6.8 cm、7.3 cm和13.1 cm;③ 西坡冰川表碛覆盖度高,表碛覆盖年均扩张率低,冰川末端退缩量小;东坡冰川表碛覆盖年均扩张率高,但表碛覆盖度总体低于西坡,冰川末端退缩量大。     

地理核心素养视角下县级博物馆研学旅行课程设计——以曲周博物馆为例

研学旅行课程设计是开展研学旅行的必要前提,结合博物馆展品设计博物馆研学旅行课程,是满足当前县级中小学在本地开展研学旅行刚需的可行途径。利用地理核心素养与县级博物馆研学旅行课程之间的契合之处,从地理核心素养的视角解读馆藏展品,并以县级的曲周博物馆为例进行课程设计。经过反思发现,博物馆展品是研学旅行课程设计的根本,博物馆科研成果决定研学旅行课程质量,博物馆本应成为区域研学旅行的集散地,博物馆联动促进区域研学旅行向纵深发展。     

贵州高原山区正负地形特征及其对人口分布的影响

正负地形可通过源汇过程对水、土资源进行再分配,影响山区的人口分布。获取正负地形数据,运用6个指标和多元逐步回归法,分析贵州高原山区正负地形特征及其对人口分布的影响。研究表明：①贵州高原山区的正负地形结构异质性明显。蚕食度、深切度、平均粗糙度比、形状指标、匀度指数、破碎度的平均值分别为1.07、371m、1.01、3.40、325和3.34,表明正地形被负地形蚕食明显、切入深度大,正、负地形的粗糙度基本相当,正负地形景观斑块呈现形状不规则、面积不均匀的破碎状态。6个正负地形指标中,匀度指数的变异性最大,变异系数为90.43%;平均粗糙度比的变异性最小,变异系数为1.06%;②贵州高原山区的人口分布不均匀性突出。人口累积达到40%时,累积面积百分比为14%;人口累积达到80%时,累积面积百分比约为50%;③6个正负地形指标中,蚕食度和深切度是影响人口分布的主要因素。蚕食度与人口密度呈正相关关系,深切度与人口密度呈负相关关系。研究成果为研究地形条件的人口影响提供补充,并为贵州高原山区人-地关系协调和土地可持续管理提供参考。     

Control factors of DIC in the Y3 seamount waters of the Western Pacific Ocean

An investigation was carried out in the Y3 seamount area of the Western Pacific Ocean in December 2014,and the distribution of dissolved inorganic carbon(DIC) and its relationship with environmental factors in this area were explored.The results show that DIC concentration was higher in the adjacent waters of the Y3 seamount area,and the uplift of DIC isolines at the stations was close to the seamount.Meanwhile,interaction between the North Equatorial Current(NEC) and the Y3 seamount affected the DIC distribution i.e.,the upwelling in the same direction of the NEC was obvious,resulting in a decreasing trend of average concentration of DIC in the 200 m water column from the top to the two side s in this direction but in the cross direction.The DIC concentration increased with the water depth increase,and its distribution was affected by various environmental factors.In the surface water,high temperature was a decisive factor for the decrease of the DIC concentration,but the photosynthesis of phytoplankton showing only a weak influence.In the North Pacific Tropic Water(NPTW),DIC production rate from organic matter decomposition was higher than that of DIC consumption by phytoplankton photosynthesis,leading to a continual increase of DIC.In the North Pacific Intermediate Water(NPIW),organic matter decomposition played a leading role in the increase of DIC.In the deep water,decomposition of organic matter weakened,and the dissolution of CaCO_3 controlled the carbonate system,and DIC had the smallest variation range.     

基于ICESat/GLAS的山东省SRTM与ASTER GDEM高程精度评价与修正

SRTM3和ASTER GDEM V2数据具有较高的空间分辨率和广泛的覆盖范围,对于地学研究具有重要意义;但在不同地形复杂度和地面覆盖物区域,两类数据的误差分布并不均匀。SRTM3和ASTER GDEM V2数据自公布以来,其精度修正一直是研究热点。然而大范围区域精度验证缺乏有效手段,传统方法可靠性差且数据获取成本较高。自ICESat-1数据公开以来,它们已成为SRTM3和ASTER GDEM V2精度评定的主要检核点。为此,本文以山东省为研究区域,借助ICESat-1评估了SRTM3和ASTER GDEM V2的高程精度,并根据插值误差曲面对两种DEM进行了修正。分析表明,原始SRTM和ASTER高程中误差分别为5.57 m和7.20 m,均高于标称精度;随着坡度的增大,高程精度呈降低的趋势。通过分析土地覆盖类型与误差分布关系表明:农田、灌丛土地类型精度较高;森林、湿地精度较低。分别采用反距离加权、普通克里金、地形转栅格和自然邻域插值方法构建误差曲面。结果表明:不同的插值方法构建的误差曲面的特征和精度也不同。其中,反距离加权修正的效果最佳,其次是地形转栅格和自然邻域,而普通克里金修正的效果最差。     

多面函数参数自适应选取方法在GPS高程拟合中的应用

提出一种综合的多面函数参数自适应选取方法。该方法利用核函数阶数和平滑因子存在最优值以及核函数结点分布应符合高程异常变化趋势的特点,综合利用正交化算法选取核函数结点以及二维粒子群算法确定最佳阶数和平滑因子,实现多面函数参数的完全自适应选取。将该方法应用于地形起伏差异不同的2个测区,结果表明,相比传统经验性方法和部分参数自适应方法,该方法用于GPS高程拟合的精度和可靠性更高。     

Objective Identification and Climatic Characteristics of Heavy-Precipitation Northeastern China Cold Vortexes

The northeastern China cold vortex(NCCV) plays an important role in regional rainstorms over East Asia. Using the National Centers for Environmental Prediction Final reanalysis dataset and the Global Precipitation Measurement product,an objective algorithm for identifying heavy-precipitation NCCV(HPCV) events was designed, and the climatological features of 164 HPCV events from 2001 to 2019 were investigated. The number of HPCV events showed an upward linear trend, with the highest frequency of ...     

The Characteristics and Controlling Factors of Water and Heat Exchanges over the Alpine Wetland in the East of the Qinghai–Tibet Plateau

Alpine wetland is one of the typical underlying surfaces on the Qinghai–Tibet Plateau. It plays a crucial role in runoff regulation. Investigations on the mechanisms of water and heat exchanges are necessary to understand the land surface processes over the alpine wetland. This study explores the characteristics of hydro-meteorological factors with in situ observations and uses the Community Land Model 5 to identify the main factors controlling water and heat exchanges.Latent heat flux and therm...     

Performance of the CMA-GD Model in Predicting Wind Speed at Wind Farms in Hubei, China

This study assesses the predictive capabilities of the CMA-GD model for wind speed prediction in two wind farms located in Hubei Province, China. The observed wind speeds at the height of 70m in wind turbines of two wind farms in Suizhou serve as the actual observation data for comparison and testing. At the same time, the wind speed predicted by the EC model is also included for comparative analysis. The results indicate that the CMA-GD model performs better than the EC model in Wind Farm A. Th...