Influence of Madden–Julian Oscillation on extreme rainfall events in Spring in southern Uruguay,International Journal of Climatology

当前位置： X-MOL 学术 › Int. J. Climatol. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Influence of Madden–Julian Oscillation on extreme rainfall events in Spring in southern Uruguay
International Journal of Climatology ( IF 3.5 ) Pub Date : 2021-01-24 , DOI: 10.1002/joc.7022
Matilde Ungerovich ₁ , Marcelo Barreiro ₂ , Cristina Masoller ₃

Affiliation

The influence of Madden–Julian Oscillation (MJO) on the dynamics of extreme rainfall events during austral Spring in Uruguay is investigated. The research is focused on the southern region of the country, which includes 15 weather stations. Extreme events are defined as days in which accumulated rainfall exceeds the 90 percentile of rainy days, and MJO is classified according to the Real‐time Multivariate MJO series 1 (RMM1) and 2 (RMM2) indices. Given that the extratropical teleconnections associated with MJO take at least 1 week to set up, we explore the influence of MJO up to 11 days prior to extreme events. A nonlinear time series analysis is performed (using symbolic patterns known as ordinal patterns) in order to consider the effects of the persistence of particular phases of MJO on the dynamic of extreme rainfall events. We find that MJO has the highest influence on extreme rainfall events in the region when it shows a persistence in phases 4 and 5 for more than 5 days, which intensifies the polar jet, influencing the trajectories of the transient waves that propagate in high latitudes, favouring geopotential disturbances over Uruguay. In other cases, the atmospheric pattern that leads to extreme rainfall events is characterized by a blocking episode that prevents transient activity from high latitudes to reach Uruguay, and the disturbances associated with the extreme events propagate along the subtropics.

中文翻译：

Madden–Julian涛动对乌拉圭南部春季极端降雨事件的影响

研究了马登—朱利安涛动（MJO）对乌拉圭南方春季极端降雨事件动力学的影响。该研究集中在该国的南部地区，其中包括15个气象站。极端事件定义为累积降雨超过雨天90％的天，并且MJO根据实时多元MJO系列1（RMM1）和2（RMM2）指数进行分类。鉴于与MJO相关的温带遥相关至少需要1周的时间才能建立，因此我们将在极端事件发生之前的11天探讨MJO的影响。进行非线性时间序列分析（使用称为序数模式的符号模式），以便考虑MJO特定阶段的持续存在对极端降雨事件动态的影响。我们发现，当MJO在第4和第5阶段持续存在超过5天时，它对该地区的极端降雨事件具有最大的影响，这会加剧极地喷气流，影响在高纬度传播的瞬变波的轨迹，有利于乌拉圭的地势干扰。在其他情况下，导致极端降雨事件的大气模式的特征是阻塞事件，阻止了高纬度的瞬时活动到达乌拉圭，与极端事件相关的干扰沿亚热带传播。有利于乌拉圭的地势干扰。在其他情况下，导致极端降雨事件的大气模式的特征是阻塞事件，阻止了高纬度的瞬时活动到达乌拉圭，与极端事件相关的干扰沿亚热带传播。有利于乌拉圭的地势干扰。在其他情况下，导致极端降雨事件的大气模式的特征是阻塞事件，阻止了高纬度的瞬时活动到达乌拉圭，与极端事件相关的干扰沿亚热带传播。

更新日期：2021-04-02

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11