Introduction
Introduction
The purpose of this training module is to provide step-by-step instructions on how to identify Atmospheric Rivers (ARs). In this module, you will learn how to interpret satellite images and model data to determine whether an atmospheric moisture band belongs to the category of ARs.
Each chapter of this training module will treat a characteristic feature of an AR. This starts with the typical moisture and cloud pattern, continues with the low-level wind regime and then with the AR's relative position to fronts and low-pressure systems. Finally, we will have a look at the weather events to be expected when ARs make landfall. At the end of each chapter, you will find an exercise where you can test your understanding.
A comprehensive analysis of Atmospheric Rivers (ARs) involves many different meteorological data sources that are ideally available to the forecaster when making the analysis. These data sources comprise satellite imagery from radiometer and microwave sensors, model forecasts and cross sections through 3-D model fields. However, in most cases, the forecaster will have to rely on data sources that are operationally available, which typically means 2-D weather charts complemented by infrared and visible satellite images.
The method presented here makes use of all the above-mentioned meteorological data and hence presupposes an ideal workspace. However, missing satellite information, such as microwave data, does not prevent a correct analysis as NWP data can be used instead. Additionally, there are freely accessible internet resources listed at the end of this training module that can be used to make the diagnosis more accurate.