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目的探讨近十年来江汉平原各县市钉螺面积时空变化特征。方法利用2003-2016年江汉平原16县市钉螺面积资料,基于四分位法、线性倾向估计、经验正交函数(EOF)分解方法,分析江汉平原近十年来钉螺面积时空变化特征及其主要空间分布型。结果江汉平原北部县市钉螺面积中位数均低于1 000hm2,南部县市在5 000hm2以上,钟祥、潜江和荆门钉螺面积四分位距在380hm2以上;江汉平原钉螺面积在2010年前呈逐年下降趋势,此后维持稳定并从2014年开始下降;江汉平原北部县市钉螺面积变化线性倾向率为正值,南部县市均为负值,钟祥和蔡甸钉螺面积变化线性倾向率分别为38.50hm2/a和-69.79hm2/a,是江汉平原钉螺面积增减速率最快地区;钉螺面积EOF分解前两个特征向量场方差贡献分别为66.6%和13.3%,空间场为“南正北负”型和“+、-、+”三极型。结论江汉平原北部县市常年钉螺面积较小,南部县市常年钉螺面积较大;钟祥、潜江和荆门钉螺面积波动幅度较大;江汉平原南部和北部钉螺面积变化趋势有明显差异。
Objective To explore the spatio-temporal variations of snail area in counties and cities of Jianghan Plain in recent ten years. Methods Based on the data of snail area from 16 counties in Jianghan Plain from 2003 to 2016, based on the quadratic method, the linear tendency estimation and the empirical orthogonal function (EOF) decomposition method, the spatio - temporal variation characteristics and the main space Distributed. Results The median size of snails in the northern counties of Jianghan Plain were below 1 000 hm 2, in southern counties above 5 000 hm 2, and that of Zhongxiang, Qianjiang and Jingmen snails above 380 hm 2; The trend of annual decline was steady afterwards and declined from 2014; the linear trend of the area change of Oncomelania snails in the counties of Jianghan Plain was positive, the counties and cities in Southern China were negative, the linear trend rates of snail areas of Zhongxiang and Caidian were 38.50hm2 / a and -69.79hm2 / a, respectively. The variance rate of snail area was the fastest in Jianghan Plain. The contribution of variance of the two eigenvectors fields was 66.6% and 13.3% respectively, and the spatial field was “Type and ” +, -, + "triode. CONCLUSIONS The perennial snails in the northern counties of Jianghan Plain are relatively small in area, while the snail areas in southern counties and cities are relatively large. The area of snail in Zhongxiang, Qianjiang and Jingmen fluctuates greatly. There are significant differences in the area of snails in the southern and northern areas of Jianghan Plain.