http://www.nature.com/articles/s41467-017-01907-4.pdf?origin=ppub
From 2012 to 2016, California experienced one of the worst droughts since the start of observational records. As in previous dry periods, precipitation-inducing winter storms were steered away from California by a persistent atmospheric ridging system in the North Pacific. Here we identify a new link between Arctic sea-ice loss and the North Pacific geopotential ridge development. In a two-step teleconnection, sea-ice changes lead to reorganization of tropical convection that in turn triggers an anticyclonic response over the North Pacific, resulting in significant drying over California. These findings suggest that the ability of climate models to accurately estimate future precipitation changes over California is also linked to the fidelity with which future sea-ice changes are simulated. We conclude that sea-ice loss of the magnitude expected in the next decades could substantially impact California’s precipitation, thus highlighting another mechanism by which human-caused climate change could exacerbate future California droughts.
-> Gaat over de droogte in Californie door hogedruk in het noordelijk deel van de Pacific. Dit hardnekkige hoog leidt tot periodiek zeer koud weer in de VS/Canada en m.i. versterking van de straalstroom op de Atl. Oceaan (dat laatste staat niet in het artikel). Onze langdurige positieve NAO-winters zouden hierdoor wel eens uit voortkomen. Achterliggende mechanisme voor het hoog zou het verlies aan zeeijs zijn.