Examination of Global Mid-Latitude Atmospheric River Lifecycle Precipitation Using an Object-oriented Methodology

Abstract:

Tracking atmospheric rivers (ARs) across their lifecycles is a field of recent interest with a multitude of emerging methodologies. The CONNected-objECT (CONNECT) algorithm is adapted for the tracking of global mid-latitude AR lifecycles and associated precipitation by implementing a seeded region growing segmentation algorithm, creating the AR-CONNECT algorithm. One of AR-CONNECT’s goals is to track atmospheric water vapor anomalies before evolving into AR geometries, effectively tracking AR genesis farther back than other studies. With the aid of sub-daily, high-resolution, satellite-derived rain data, we investigate the climatology, trends, and patterns of AR lifecycle precipitation from 1983-2016 and compare with other AR tracking studies. We find that mid-latitude precipitation uncovered by AR-CONNECT shows contributions up to 50% over land and 65% over the ocean. Trend analysis of AR precipitation show an increase in precipitation associated with Southern Hemisphere and Saharan ARs, among others, but is determined not to be a driver of changes in global precipitation.