夏季尤其是6-7月长江流域（27°–31° N, 107°–120° E）降水与前期冬季12-1月青藏高原地区对流层中上层气温具有显著的相关关系。定义青藏高原地区（25°–40°N, 80°–100°E）500-250 hPa平均扰动温度（温度减去纬向平均值）为青藏高原对流层温度（TPTT）指数（标准化，气候平均态为1991-2020年）。该指数可以用来预测长江流域夏季降水异常。
参考文献：
Zhu, X. Y., M. Z. Yang, G. Liu, Y. J. Liu, W. J. Li, S. L. Nan, and L. H. Sun, 2023: A precursory signal of June–July precipitation over the Yangtze River Basin: December–January tropospheric temperature over the Tibetan Plateau. Adv. Atmos. Sci., https://doi.org/10.1007/s00376-022-2079-1.
Zhu, X. Y., M. Z. Yang, G. Liu, Y. J. Liu, W. J. Li, S. L. Nan, and L. H. Sun, 2023: A precursory signal of June–July precipitation over the Yangtze River Basin: December–January tropospheric temperature over the Tibetan Plateau. Adv. Atmos. Sci., https://doi.org/10.1007/s00376-022-2079-1.