High-resolution Radar analysis of precipitation extremes in Ecuador and North Peru and implications of the ENSO-dynamics

厄瓜多尔和秘鲁北部极端降水的高分辨率雷达分析以及 ENSO 动态的影响

• 批准号: 398620920
• 负责人: Privatdozent Dr. Rütger Rollenbeck
• 金额: --
• 依托单位: Labor für Climatology and Remote Sensing -LCRS
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/398620920?language=en
• 关键词: resolution; Radar; analysis; precipitation; extremes

The aim of this research is the observation and analysis of regional precipitation extremes and the associated atmospheric dynamics of circulation in the meteorologically complex transition zone from the coastal plains of southern Ecuador and northern Peru across the Andes to the eastern foot zone of the mountains. A longer time series from 2014 to 2020 of the weather radar systems of RadarNetSur (www. Radarnetsur.gob.ec) allows to identify and explain relevant spatio-temporal patterns like persistent, transient end episodic cycles. The diurnal cycle is shaped by small-scale local circulation systems like the mountain-valley-, the land-sea-breeze or the confluence of synoptical flows and katabatic winds. They lead to a characteristic pattern of precipitation genesis, which cannot be registered by point observations. In Radar imagery they show up in detail and their spatial distribution will be visible. This enables to understand the high heterogeneity of the diurnal cycle and the occurrence of extremes as dependent on the topography. Dependent on the synoptic wind situation such patterns also change their location. This superordinate control in its spatial extent can only be observed by weather radar by deriving typical spatio-temporal patterns in relation to the larger-scale weather situation. As a result, detailed maps of the diurnal and annual cycle of precipitation and areas with a high potential for extreme events are generated. The arid climate of the coastal regions is caused by large scale subsidence, but episodically deep convection occurs. Convective cells with extreme precipitation are propagating eastwards and cause local flooding, more frequently in the southern sub-regions. Genesis and typical pathways are analyzed by using profiles of precipitation intensity and associated dynamic convergence zones, which form during such events. The movement profile of such dynamic convergence zones is indicative for the relation of their genesis to the synoptical and spatial context and shows areas of elevated risk for extreme events. Also, regional differences of the whole study region caused by topography and general exposition are shown. Regional differences are also an important aspect of the longer-term influence on the genesis of extreme precipitation. For each sub-region the effect of temperature anomalies of the costal (El-Niño-region 1+2) and central pacific (EN-region 3+4) will be analysed, especially their modifying influence on local precipitation enhancement by topographic and synoptic factors.

本研究的目的是观测和分析从厄瓜多尔南部和秘鲁北部沿海平原穿过安第斯山脉到山脉东麓地区的气象复杂过渡区的区域极端降水和相关的大气环流动态。 RadarNetSur (www. Radarnetsur.gob.ec) 天气雷达系统从 2014 年到 2020 年的较长时间序列可以识别和解释相关的时空模式，例如持续、瞬态结束的情景周期。昼夜循环是由小规模的局部环流系统形成的，例如山谷、陆地-海风或天气流和下降风的汇合。它们导致了降水发生的特征模式，而这种模式无法通过点观测来记录。在雷达图像中，它们会详细显示，并且它们的空间分布将可见。这使得我们能够理解昼夜周期的高度异质性以及取决于地形的极端事件的发生。根据天气风况，这些模式也会改变其位置。这种空间范围的上级控制只能通过气象雷达通过导出与更大范围的天气情况相关的典型时空模式来观察。由此，生成了降水日间和年度循环以及极有可能发生极端事件的区域的详细地图。沿海地区的干旱气候是由大规模沉降造成的，但间断发生深对流。极端降水的对流单体正向东传播，造成局地洪涝，其中南部次区域更为频繁。通过使用降水强度剖面和在此类事件期间形成的相关动态辐合区来分析成因和典型路径。这种动态汇聚区域的运动概况表明了它们的起源与天气和空间背景的关系，并显示了极端事件风险较高的区域。此外，还显示了整个研究区域因地形而引起的区域差异和一般说明。区域差异也是对极端降水成因的长期影响的一个重要方面。对于每个子区域，将分析沿海（厄尔尼诺区域1+2）和太平洋中部（EN区域3+4）温度异常的影响，特别是地形和天气因素对局部降水增强的修正影响。