气候变化背景下秦岭-淮河地区亚热带北界变化

基于1970—2019年秦岭-淮河地区气象站点观测数据，以日均温稳定≥10℃持续日为主要指标，以1月平均气温为辅助指标，借助薄盘样条插值（TPS）及基于数字高程模型（DEM）的普通克里金插值法，探讨秦岭-淮河地区亚热带北界对全球气候变暖及变暖“停滞”现象的响应及变化。结果表明，1970—2019年秦岭-淮河地区日均温稳定≥10℃持续日及1月平均气温均呈不同程度的上升趋势，但二者高低值的分布年份并不相同；50年来亚热带北界在秦岭段出现了明显的向高海拔地区移动的趋势，其中，秦岭南坡共计抬升153.3 m，北坡抬升148.8 m。在变暖“停滞”期间，秦岭南、北坡亚热带北界所处海拔的变化具有较高的同步性，但在1980s至1990s期间差异性较大。1970—2019年亚热带北界在淮河段北移1.3个纬度以上，在115°E附近甚至达到3个纬度，与中国过去2000年亚热带北界曾到达的最北位置相仿；从年代际上来看，亚热带北界在1990s期间北移最明显，黄河流域下游部分区域已由暖温带逐渐转化为亚热带。

Change of subtropical northern boundary in Qinling?Huaihe region in the context of climate change

Based on the observation data of meteorological stations in the Qinling-Huaihe region from 1970 to 2019, with daily average temperature stability ≥10℃continuous days as the main indicator, and January average temperature as the auxiliary indicator, with the help of Thin Plate Spline (TPS) and the ordinary Kriging interpolation method based on Digital Elevation Model (DEM), to explore the response and changes of the subtropical northern boundary in Qinling-Huaihe region to global warming and warming hiatus. From 1970 to 2019, the daily average temperature stability≥10℃continuous days in Qinling-Huaihe region and the January average temperature showed an upward trend of varying degrees, but the distribution years of the high and low values were different. In the past 50 years, the subtropical northern boundary has shown an obvious trend of moving to high-altitude areas in the Qinling section. Among them, the southern slope of the Qinling Mountains has been uplifted by 153.3 m in total, and the northern slope has been uplifted by 148.8 m. During the period of warming hiatus, the elevation changes of the subtropical northern boundary of the southern and northern slopes of the Qinling Mountains were highly synchronized, but they were quite different from 1980s to 1990s. From 1970 to 2019, the subtropical northern boundary moved northward by more than 1.3 latitudes in the Huaihe River section, and even reached 3 latitudes near 115°E, which is similar to the northernmost position that the subtropical northern boundary of China has reached in the past 2000 years. From the perspective of different ages, the northward movement of the subtropical northern boundary was most obvious during the 1990s, parts of the lower Yellow River basin have been gradually transformed from warm temperate to subtropical.