This study surveys the variability and predictability of the position, magnitude, and size of warm-pool El Niño (WP El Niño), as well as its impacts on the climate. A new detection method for WP El Niño that is flexible regarding its position, magnitude, and size is developed. Thirteen WP El Niño events are found from 1950 to 2018 using this detector. These events have a mean (standard deviation) center position of 31.7 (12.4)° longitude, a mean peak sea surface temperature anomaly (SSTA) of 1.87 (0.62) K, and a zonal size parameter of 19.99 (5.13)° longitude. Also, stronger WP El Niño events tend to be larger and take place farther east. Based on these distributions, a set of model experiments is conducted to evaluate climate sensitivity to these three features. The wintertime North American temperature dipole due to WP El Niño is chosen as an example. Its bearing is linearly controlled by the position of the SSTA field of WP El Niño, and this control is stronger when the SSTA field is stronger or smaller. Predictability of position, magnitude, and size of WP El Niño on seasonal scale by the North American Multi-Model Ensemble is examined. With a 2-month lead-time, the position and magnitude of WP El Niño are predicted accurately, but size tends to be large-biased. Increasing the lead-time generally leads to more eastward bias, cold bias, and large bias. Precision of the predictions is also reduced with lead-time.

中文翻译：

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暖池厄尔尼诺现象的位置、幅度和大小：变异性、季节性可预测性和气候影响

本研究调查了暖池厄尔尼诺现象 (WP El Niño) 的位置、幅度和大小的可变性和可预测性，及其对气候的影响。开发了一种新的 WP 厄尔尼诺现象检测方法，该方法在其位置、震级和大小方面具有灵活性。使用该探测器在 1950 年至 2018 年间发现了 13 次 WP 厄尔尼诺现象。这些事件的平均（标准偏差）中心位置为 31.7 (12.4)° 经度，平均峰值海面温度异常 (SSTA) 为 1.87 (0.62) K，纬向大小参数为 19.99 (5.13)° 经度。此外，更强的 WP 厄尔尼诺现象往往更大，发生在更远的东部。基于这些分布，进行了一组模型实验来评估气候对这三个特征的敏感性。以 WP El Niño 引起的冬季北美温度偶极子为例。其方位受 WP El Niño 的 SSTA 场位置的线性控制，当 SSTA 场越强或越小，这种控制就越强。研究了北美多模式集合在季节性尺度上对 WP 厄尔尼诺现象的位置、幅度和大小的可预测性。提前 2 个月，可准确预测 WP 厄尔尼诺现象的位置和强度，但规模往往存在较大偏差。增加提前期通常会导致更多的东偏、冷偏和大偏。预测的精确度也会随着提前期而降低。研究了北美多模式集合在季节性尺度上的 WP 厄尔尼诺现象的幅度和大小。提前 2 个月，可准确预测 WP 厄尔尼诺现象的位置和强度，但规模往往存在较大偏差。增加提前期通常会导致更多的东偏、冷偏和大偏。预测的精确度也会随着提前期而降低。研究了北美多模式集合在季节性尺度上的 WP 厄尔尼诺现象的幅度和大小。提前 2 个月，可准确预测 WP 厄尔尼诺现象的位置和强度，但规模往往存在较大偏差。增加提前期通常会导致更多的东偏、冷偏和大偏。预测的精确度也会随着提前期而降低。