热带降水对当地海面温度的高度敏感性
Peter Good1, Robin Chadwick2,3, Christopher E Holloway4
1MetOffice Hadley Centre, Exeter, UK. peter.good@metoffice.gov.uk.
Nature
|October 27, 2020
概括
热带海洋的温度对全球天气有很大影响. 新的研究表明降水对海面温度非常敏感, 这对于改善气候模型和预测至关重要.
科学领域:
- 气候科学
- 大气科学
- 海洋学
背景情况:
- 热带海洋表面温度是全球天气和气候的关键驱动因素,通过结合降水和大气循环过程.
- 现有的气候模型表现出偏差,例如不准确的热带雨带和弱的厄尔尼诺南部振荡 (ENSO) 反应,表明了解海洋与大气相互作用的差距.
- 浅层大气循环对降水的影响及其与深层循环相互作用的作用尚不清楚,进一步复杂化了气候模型.
研究的目的:
- 使用观测数据量化季节性热带降雨对当地海面温度的敏感性.
- 将观测估计的降水灵敏度与气候模型的估计进行比较.
- 确定浅层循环与模型偏差之间的联系,以改善未来的气候预测.
主要方法:
- 分析多个独立的观测数据集,物理约束和气候模型数据.
- 估计每单位和特异性湿度的降水变化,作为海面温度的函数.
- 对气候模型性能与观测估计进行评估,并评估与浅层对流相关的偏差.
主要成果:
- 观测到的季节性热带降雨显示,每克和特异性湿度变化对当地的海面温度有80%的高灵敏度.
- 这种观察到的灵敏度明显高于大多数 (47个中43个) 的气候模型.
- 具有更现实的降水灵敏度 (接近80%) 的模型显示各种指标的偏差减少,特别是与浅层对流相关的模型.
结论:
- 热带降水对海面温度的高度敏感性,由浅水循环驱动,对于准确的气候建模至关重要.
- 改善气候模型中浅层对流和降水敏感性的表现对于减少偏差和提高季节性预测和多十年气候预测的可靠性至关重要.
- 这项研究为未来的研究提供了明确的重点,以提高对海洋和大气合及其对全球气候的影响的理解.
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