基于Mann-Kendall法的林芝市农业界限温度变化特征分析

Analysis on Agricultural Boundary Temperature Change Characteristics in Linzhi City Based on Mann-Kendall Method

为探明1971年以来林芝市农业气象界限温度变化及突变情况,采用五日滑动分析法和Mann-Kendall趋势分析法计算初始日、终止日、持续天数等≥0℃农业气象界限温度指标。结果表明,林芝市起始日变幅较大,介于1-2月之间;终止日变幅较小,集中在12月,且随着年份的增大,呈现出一定的延期趋势。持续天数呈现明显增长趋势。1975年存在1个突变点,且部分年份为0.05水平上的显著性增温。建议林芝市青稞、油菜等春播作物可以进行适时早播或冬播。

In order to explore the change and sudden change situation of agricultural boundary temperature in Linzhi City since 1971,the agricultural boundary temperature (≥0 ℃ )indexes such as initial day,terminal day and duration were calculated by using 5-day sliding average analysis and Mann-Kendall method. The results showed that the range of initial day in Linzhi City was wide,which was from January to February;the range of terminal day was narrow,which was concentrated in December,and there was a delayed trend year by year. The duration showed an obvious increase trend. There was a sudden change point in 1975,and the temperature increased significantly at the level of 0.05 in some years. It ’s suggested that barley,rape and other spring crops could be sowed in advance or in winter.