3 years ago

Modulation of the MJO intensity over the equatorial western Pacific by two types of El Niño

Tomoe Nasuno, Swadhin K. Behera, Lin Chen, Lu Wang, Tim Li

Abstract

The modulation of the Madden–Julian Oscillation (MJO) intensity by eastern Pacific (EP) type and central Pacific (CP) type of El Niño was investigated using observed data during the period of 1979–2013. MJO intensity is weakened (strengthened) over the equatorial western Pacific from November to April during EP (CP) El Niño. The difference arises from distinctive tendencies of column-integrated moist static energy (MSE) anomaly in the region. A larger positive MSE tendency was found during the convection developing period in the CP MJO than the EP MJO. The tendency difference is mainly caused by three meridional moisture advection processes: the advection of the background moisture by the intraseasonal wind anomaly, the advection of intraseasonal moisture anomaly by the mean wind and the nonlinear eddy advection. The advections’ differences are primarily caused by different intraseasonal perturbations and high-frequency activity whereas the background flow and moisture gradient are similar. The amplitudes in the intraseasonal suppressed convection anomaly over the central Pacific is critical in modulating the three meridional moisture advection processes. The influences on the central Pacific convection anomaly from seasonal mean moisture in two types of El Niños are discussed.

Publisher URL: https://link.springer.com/article/10.1007/s00382-017-3949-6

DOI: 10.1007/s00382-017-3949-6

You might also like
Never Miss Important Research

Researcher is an app designed by academics, for academics. Create a personalised feed in two minutes.
Choose from over 15,000 academics journals covering ten research areas then let Researcher deliver you papers tailored to your interests each day.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.