The 3-Week-Long Transport History and Deep Tropical Origin of the 2021 Extreme Heat Wave in the Pacific Northwest

Author(s)
Katharina Baier, Marcus Rubel, Andreas Stohl
Abstract

The heat wave in late June of 2021 (PNW21) set new temperature records in the Pacific Northwest (PNW). In Lytton the highest temperature ever recorded in Canada was measured. Several studies have already explored this extreme event in detail, however, here we compare the atmospheric air mass transport and heating processes associated with this heat wave with the 34 other most extreme heat events in the same region during the period 1960–2021, using a long backtracking time of 25 days. We found significant differences in the heat waves. During PNW21 most of the air was coming from the Philippine Sea, with more than 40% of the air located south of 15°N, and anomalous advection of sensible and latent heat from the Tropics was the dominant cause of PNW21. The latent heat was efficiently converted into sensible heat by precipitation, which was unique, as most other extremes experienced net diabatic cooling.

Organisation(s)
Department of Meteorology and Geophysics
Journal
Geophysical Research Letters
Volume
50
ISSN
0094-8276
DOI
https://doi.org/10.1029/2023GL105865
Publication date
12-2023
Peer reviewed
Yes
Austrian Fields of Science 2012
105206 Meteorology
Keywords
ASJC Scopus subject areas
Geophysics, General Earth and Planetary Sciences
Portal url
https://ucrisportal.univie.ac.at/en/publications/4206a956-6db5-4706-9a67-d847f43072aa