热带北界一直是中国综合自然区划研究中争议较大的问题之一,不同学者基于不同区划指标和方法等划定的中国热带北界界线差异较大。基于空间分异性的综合自然区划思想,依托最新的基于统计学原理的地理探测器模型,以气候要素为主导指标,辅以土壤类型与作物熟制等,探讨中国陆地热带北界的界线。结果表明:1依据地理探测器模型所确定的中国陆地热带北界,自西向东依次经过滇、桂、粤和闽的临沧、思茅、玉溪、个旧、百色、马山、贵港、梧州、肇庆、广州、惠州、河源、梅州、漳州、泉州和莆田等地附近,其与最冷月均温12℃等温线、赤红壤与红壤界线及双季稻或双季稻连作喜温旱作与单(双)季稻连作喜凉旱作的分界线等基本吻合;2利用地理探测器确定的中国陆地热带北界新界线的各项指标决定力q值的均值为0.40,分异明显,满足层内同质性和层间异质性最大的区划原则,完全达到了热带与亚热带的区域空间异质性要求,其划分结果合理可信,表明地理探测器模型可为综合自然区划提供良好的技术支撑。
The northern border of the tropical zone of China has been the focus of studies on comprehensive physical regionalization. Based on different indexes and methods, the border was delineated by different scholars, but their results varied greatly. Based on the Geodetector model and regionalization thought of spatial stratified heterogeneity, the northern border of the tropical zone of China’s mainland was investigated. Climatic elements were used as dominant demarcation partitioning indexes, combined with auxiliary indexes such as soil and multiple cropping types. The key results were as follows:(1) Using Geodetector, the northern border of the tropical zone was delineated. From west to east, the border goes through Lincang, Simao,Yuxi and Gejiu in Yunnan, Baise, Mashan, Guigang and Wuzhou in Guangxi, Zhaoqing,Guangzhou, Huizhou, Heyuan and Meizhou in Guangdong, and Zhangzhou, Quanzhou and Putian in Fujian. It generally agrees with the 12℃ isotherm of the coldest monthly mean temperature, soil border between lateritic red soil and red soil, and border of double cropping rice or its continuous thermophile dry framing and single(double) cropping rice or its continuous chimonophilous dry framing.(2) The q average value of all indexes for the border was 0.40. Using this model, regionalization principles—homogeneity of the within-strata value and heterogeneity of the between- strata value—were satisfied. The border meets the requirements of zonal heterogeneity between tropical and subtropical zones. Therefore, it is reasonable to use Geodetector in studies of comprehensive physical regionalization, and it can provide high-precision technical support.