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

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到安第斯山脉东部山脚地区的复杂气象过渡区内的区域极端降水和相关的大气环流动力学。RadarNetSur （www.radarnetsur）气象雷达系统2014 - 2020年的较长时间序列。Radarnetsur.gob。(c)允许识别和解释相关的时空模式，如持续的，短暂的结束事件周期。日循环是由小规模的局部环流系统形成的，如山谷、陆海风或天气流和降风的汇合。它们导致降水成因的特征模式，这是不能通过点观测记录的。在雷达图像中，它们详细地显示出来，它们的空间分布将是可见的。这使我们能够理解日循环的高度异质性和极端事件的发生取决于地形。根据天气风的情况，这些模式也会改变它们的位置。这种在空间范围上的超常控制只能由气象雷达通过推导与更大尺度天气情况有关的典型时空模式来观测。结果，生成了降水日和年周期的详细地图，以及极端事件发生可能性高的地区。沿海地区的干旱气候是由大规模的沉降引起的，但偶尔也会发生深对流。极端降水的对流单体向东传播，造成局部洪水，在南部次区域更为频繁。利用降水强度剖面图和相关的动力辐合带，分析了这些事件的成因和典型途径。这种动态辐合带的运动剖面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增加的地区。此外，还显示了整个研究区域因地形和一般博览会引起的区域差异。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。对于每个分区，将分析沿海（El-Niño-region 1+2）和中太平洋（en - 3+4）温度异常的影响，特别是它们对地形和天气因子对局地降水增强的修正影响。

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.