Affiliation:
1. Meteorology and Air Quality Section Environmental Sciences Group Wageningen University Wageningen The Netherlands
2. Faculty of Science Institute for Atmospheric and Earth System Research/Physics University of Helsinki Helsinki Finland
Abstract
AbstractThe effect of modified equator‐to‐pole temperature gradients on the jet stream by low‐level polar warming and upper‐level tropical warming is not fully understood. We perform aquaplanet simulations to quantify the impact of different sea surface temperature distributions on jet stream strength, large wave amplitudes and extreme waviness. The responses to warming in the waviness metrics Sinuosity Index and Local Wave Activity are sensitive to the latitude range over which they are calculated. Therefore, we use a latitude range that accurately represents the position of the jet. The uniform warming scenario strengthens the jet and reduces large wave amplitudes. Reductions in meridional temperature gradients lead to weakened mid‐latitudinal jet strength and show significant decreases in large wave amplitudes and jet stream waviness. These findings contradict the mechanism that weakened jet streams increase wave amplitudes and extreme jet stream waviness. We conclude that weakened jet streams do not necessarily become wavier.
Funder
Research Council of Finland
Publisher
American Geophysical Union (AGU)