江南华南茶树旱热复合灾害指标及时空特征

Construction of a Compound Heat and Drought Damage Index and Spatiotemporal Characteristics for Tea Plants in South of the Yangtze River and South China

  • 摘要: 利用1961—2022年江南华南茶区494个气象站的日最高气温和降水量数据、茶树旱热害灾情记录, 在已有茶树高温热害等级指标基础上, 根据连续无雨日数计算干旱指数, 考虑高温与干旱的叠加效应, 采用椭圆曲线方法构建基于高温日数和干旱指数的茶树旱热害等级指标并验证, 进而分析江南华南茶区的旱热害时空分布特征。结果表明:以高温持续日数和干旱指数分别为椭圆曲线的两个半轴, 得到茶树旱热害轻度-中度、中度-重度临界阈值的高温持续日数阈值分别为17 d和38 d, 干旱指数阈值分别为15.1 d和29.4 d;验证样本判识的茶树旱热害等级完全准确率和基本准确率分别为60%和100%;1961—2022年江南华南茶区中度旱热害发生范围最大, 轻度旱热害平均频次最高, 重度旱热害的范围和频次均最小;1961—2022年江南华南茶区旱热害的范围和频次呈波动上升趋势, 1991—2000年最低, 2011—2022年最高;旱热害频次呈中间高、沿海低的空间分布特征。

     

    Abstract: Based on daily maximum temperature and precipitation data of tea regions over South of the Yangtze River and South China from 494 meteorological stations from 1961 to 2022, as well as records of compound heat and drought damage of tea trees, a compound index is calculated on the basis of existing high temperature and heat damage grade index uses the number of consecutive days without rain. Considering the superimposed effect of drought and heat damage, the compound heat and drought damage grade index of tea plants is constructed based on the elliptic curve method and verified, and then spatiotemporal characteristics of compound heat and drought damage in South of the Yangtze River and South China are analyzed. Results indicate that the compound heat and drought damage grade index for tea plants is constructed using the duration of high-temperature days and the drought index as two axes of the elliptical curve. The high temperature duration days for mild to moderate and moderate to severe compound heat and drought damage are 17 d and 38 d, respectively, and the drought index for mild to moderate and moderate to severe compound heat and drought damage 15.1 d and 29.4 d, respectively. The overall accuracy and basic accuracy of the compound heat and drought damage grade index for tea plants, constructed using elliptic curves to identify validation samples, are 60% and 100%, respectively. From 1961 to 2022, the average occurrence range of moderate compound heat and drought damage in tea regions over South of the Yangtze River and South China is the largest, the average frequency of mild compound heat and drought damage is the highest, and the average range and frequency of severe compound heat and drought damage are the smallest. The range and frequency of compound heat and drought damage in tea plants over South of the Yangtze River and South China show a fluctuating upward trend from 1961 to 2022, with the lowest in the 1991-2000 period and the highest in the 2011-2022 period. The spatial distribution of compound heat and drought damage frequency is characterized by a high incidence in the central region and a low incidence in the coastal areas.

     

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