Positive feedback between East Asian mid-latitude circulation and land surface temperature

Positive feedback between East Asian mid-latitude circulation and land surface temperature
Standardized time series of the indices for the northern flank of the EAJ (EAJNI, blue solid line), surface air temperature in the Russian Far East (TSI, red dashed line) and EAJ (black dashed line). Credit: LIn Xiaozhen

The interannual variability of the East Asian upper-tropospheric westerly jet (EAJ) in summer is characterized by the meridional displacement of its axis, or a seesaw pattern of zonal wind anomalies between the northern and southern flanks of the EAJ. It plays a crucial role in summer climate anomalies in East Asia.

"Interannual variation of the meridional displacement of the EAJ relates to the tropical air-sea interaction, but mainly for the southern flank of EAJ," said LIN Xiaozhen, a master program student in the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences, and also the first author of a paper published in Atmospheric and Oceanic Science Letters.

"We found a close relationship between the surface air temperature in the Russian Far East and the northern flank of the EAJ and revealed a positive feedback mechanism between them," she said.

LIN's study indicated that related to a warmer surface in the Russian Far East, the westerly decelerates in the northern flank of the EAJ. The anticyclonic circulation anomaly related to a weakened westerly in the northern flank of the EAJ induced surface warming in the Russian Far East and the warmer surface could in turn act as a heat source and induce a local anticyclonic circulation in the upper troposphere, therefore decelerating the westerly in the northern flank of the EAJ.

These results implied that a better description of the summer condition in the Russian Far East may benefit seasonal forecasts of the EAJ and, subsequently, East Asian summer climate.


Explore further

Meteorological silk road pattern may take a toll on Eurasian climate in north-jet years

More information: Xiao-Zhen LIN et al, Close relationship between the East Asian westerly jet and Russian Far East surface air temperature in summer, Atmospheric and Oceanic Science Letters (2018). DOI: 10.1080/16742834.2018.1467726
Citation: Positive feedback between East Asian mid-latitude circulation and land surface temperature (2018, May 30) retrieved 15 September 2019 from https://phys.org/news/2018-05-positive-feedback-east-asian-mid-latitude.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
4 shares

Feedback to editors

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more