Details

Autor(en) / Beteiligte

• Totz, Sonja
• Petri, Stefan
• Lehmann, Jascha
• Coumou, Dim

Titel

Regional Changes in the Mean Position and Variability of the Tropical Edge

Ist Teil von

• Geophysical research letters, 2018-11, Vol.45 (21), p.12,076-12,084

Ort / Verlag

Washington: John Wiley & Sons, Inc

Erscheinungsjahr

2018

Quelle

Wiley Online Library Journals Frontfile Complete

Beschreibungen/Notizen

• Recent studies indicate that the tropical belt has been expanding during recent decades, which can significantly influence precipitation in subtropical climates. Often the location of the tropical border is identified using the Hadley cell edge (HCE) or the subtropical jet stream (STJ), but most studies concentrated on the zonal‐mean state, thereby missing regional impacts. Here we detect longitudinal‐resolved trends in STJ cores and HCEs over 1979–2016 in both hemispheres at a higher spatial and temporal resolution than previous studies. Besides pronounced regional trend differences in both sign and magnitude, we show that winter HCE and STJ variability increased in the Mediterranean region and decreased over the American and Asian continents. Rainfall variability in these regions changed likewise, and most of those changes can be explained by changes in HCE/STJ variability. This highlights the importance of understanding future tropical belt changes both regionally and in terms of variability. Plain Language Summary We applied a new network‐based method to detect motion of the tropical climate border with longitudinal resolution. Depending on the longitudinal position, there are differences in both direction and magnitude of the border motion. In addition, we demonstrate that the rainfall variability is increasing in the Mediterranean region and decreasing over the American and Asian continents, which can be explained by the variability of the tropical belt location. Key Points Longitudinally resolved trends for the Hadley cell edge (HCE) and the subtropical jet (STJ) core are provided The observed zonal‐mean poleward shift consists of pronounced regional differences in both magnitude and sign of the trends The increased year‐to‐year variability of the HCE in the Mediterranean can explain most of the increased variability in precipitation here