Abstract:
Convectively coupled equatorial waves serves as the primary source of information
for understanding the highly coupled ocean-atmosphere system. Since the spatiotemporal
scales of equatorial waves fall conveniently between those of weather and
climate, they can influence both the scales. In this study we plan to focus on the effect
of mean states on equatorial waves to better understand the interaction of equatorial
waves with weather and climate scales under different background conditions. They
study may provide important insight on equatorial wave dynamics in a warming environment.
Chapter 1: Space time spectral analysis was performed on daily OLR and U850
data to identify the spectral signatures of equatorial waves. Coherence-squared spectra
was also performed on OLR with U850 to study the correlation between the equatorial
wave signals in OLR and U850. Further wave-filtered OLR was used to locate
the active regions of equatorial wave activity. Preferential peaking of equatorial wave
activities during different phases of ENSO was identified.
Chapter 2: Vertical propagation of equatorial waves under different background
states was studied. Linear regression technique and Empirical Orthogonal Function
analysis were used to identify the convective patterns of equatorial waves. Preferential
vertical propagation of equatorial waves during different phases of QBO was identified.
Chapter 3: OLR, U850 and U200 data from five global climate models that efficiently
simulate MJO are compared with observation results to observe how well these
models simulate convectively coupled equatorial waves in the troposphere, using the
same analysis performed in Chapter 1.
