多隐层BP神经网络在模式预报中的简化应用

EC细网格预报效果好,基本满足业务需要,在工作中被广泛应用。为进一步提升预报准确性,做好迪士尼园区的气象服务保障,选取2016年7月至2017年6月1年的2 m温度预报场,24 h预报时效的时间分辨率为3 h,72 h预报时效的时间分辨率为24 h,分别用回归分析法、S型和简化Line型BP神经网络法进行模式释用,与迪士尼气象站观测数据对比。结果表明:阈值为1℃时,对模式结果释用后,均方根误差减少了0.5℃到1.0℃,3—9 h和21—72 h预报时效的准确率由原来的50%和30%分别上升到70%和50%。采用S型多隐层BP神经网络误差最小,不同预报时效释用稳定性最高,同时该释用方法对t_(min)的预报特征把握更精准,释用效果明显优于对t_(max)的预报释用,但迭代计算耗费时间大幅增多,与预报效果的提升不成正比。简化Line型的BP神经网络通过8个半月的数据量和简单的网络模式,捕获了EC预报的特征,不但减小了计算量,大幅缩短了计算时间,而且预报结果也有显著提升,预报稳定性较好,具有广泛的业务应用空间。     

城市群飞地型斑块空间活力对比 ——以中国三大城市群为例

飞地增长是指新增建设用地与原有建设用地相离的扩张方式,是快速城市化的中国城市发展中普遍存在的现象.本文以多源地理大数据以及土地利用数据为基础,在斑块尺度单元,测度中国三大城市群在1995—2015年间新增飞地斑块空间活力水平.研究表明:长三角地区飞地斑块数量最多、总面积最大,而斑块空间活力最低;珠三角地区的飞地斑块数量...     

香河家具城，典型飞地的模范崛起

这里西接北京、东邻天津、不与行政管辖所属河北省接壤,不仅是全国面积最大的飞地,而且被首都和中央直辖市环抱,也可算全国级别最高的飞地。     

飞地——奇特的地理单元

政治地理学中的飞地是指境外的领地，又称为被包围领土。这种领土虽在其它国家包围之中，但所属国却对其拥有完全的主权。本文所淡飞地即是这种与本土的政治、经济、文化等方面的联系，必须借道它国的陆、海、空走廊的地理单元。     

Clarification and research progress of tourism island-related concepts北大核心CSCD

：In the context of high-quality development, the conflicting relationship between tourist areas and surrounding communities has become a severe obstacle to the realization of high-quality economic development. As a theoretical tool to describe the relationship between tourist areas and surrounding communities, the concept of tourism island is of great value in identifying, assessing, and managing the conflicts between tourist areas and surrounding communities. Therefore, it has gradually become a new topic in geography, sociology, economics, and other related disciplines. On the basis of distinguishing and analyzing the three interrelated concepts of tourism enclave, tourism bubble, and tourism island, this article systematically reviewed the research progress from the four aspects of tourism island types, key characteristics, causes of formation, and impacts, and found that the current research still has obvious deficiencies in theoretical framework, empirical research, and governance system. Finally, this article proposed three specific directions for further research based on the shortcomings of the current research. Based on the practice of Chinese tourism development, a theoretical framework of tourism island should be constructed, the formation processes and impacts of tourism island should be explored using diversified methods of analysis, and a multi-dimensional, multi-level, and multi-process regulatory mechanism should be developed. Overall, this article presented a systematic review of the previous research literature on tourism island to show their results and quality; it also clarified the starting point for further research and laid a foundation for new research works. © 2023, Editorial office of PROGRESS IN GEOGRAPHY. All rights reserved.     

齐鲁劲吹节地风——山东省节约集约用地路径探析

正数字看山东,土地资源严重不足。这是一个人口大省,同时又是土地资源小省——作为全国人口最多、发展速度最快的地区之一,山东人均耕地面积只有全国人均水平的77.6%,以占全国1.6%的土地面积、6.2%的耕地面积,承载着全国10.4%的生产总值、提供占全国8.2%的粮食、养活占全国7.1%的人口。与此同时,山东的土地承载着巨大的供需压力,由于处于城镇化、工业化、农业现代化快速发     

地图上消失的名字（十一）东普鲁士：飞地的命运

东普鲁士,从字面意思看,是指普鲁土的东部地区。而飞地,是一个地理学名词,简单点说,就是孤悬在外的领土。东普鲁士这块土地,似乎生来就是做飞地的命,在短短300多年的时间里,竟然先后做了三次飞地。直到今天,虽已更名易主,仍摆脱不了作为飞地的命运。