TITLE:
Madden Julian Oscillations in Total Column Ozone, Air Temperature and Surface Pressure Measured over Cochin during Summer Monsoon 2015
AUTHORS:
Vazhathottathil Madhu
KEYWORDS:
Intra-Seasonal Oscillations, Total Column Ozone (TCO), Madden Julian Oscillation, Wavelet Analysis
JOURNAL NAME:
Open Journal of Marine Science,
Vol.6 No.2,
April
18,
2016
ABSTRACT: The intra-seasonal
variability plays a major role in the inter-annual variability of weather
parameters such as rainfall, temperature and pressure which lead to extreme
weather events in certain years. The active (more rainy days) and break (less
rainy days) periods of Indian summer monsoon heavily depend on the
intra-seasonal variability of weather parameters such as wind, pressure and
temperature oscillations during the monsoon season. In the present analysis
daily total column ozone, surface temperature and surface pressure measured
over Cochin using Microtop II Ozonometer (sun Photometer) were used to study
the Intra-Seasonal Variations (ISV) of the above parameters during the monsoon
season, 2015. The dominant and significant intra-seasonal oscillations (ISOs)
were identified using an advanced statistical method called the Discrete
Mayer’s Wavelet (DMW) analysis. Two major ISOs such as Madden Julian
Oscillations (MJO, 30 - 60 days) and quasi-bi weekly (12 - 16 days)
oscillations were found in TCO, surface temperature and pressure. In TCO an
additional mode of ISO with quasi tri-weekly periodicity was also found (16 -
22 day). It is observed that MJO mode is the dominant among all other modes and
its positive and negative phases correlate with positive and negative anomalies
of the above parameters. The ISO mode in the surface pressure shows an out of
phase relation with the Indian summer monsoon rainfall which indicates the
active and break periods of Indian summer monsoon. The contribution of MJO mode
is dominant in the tropical atmosphere, which modulates the intra-seasonal
variability. It is found that for the year 2015 total column ozone, surface
pressure and surface temperature show an annual range of 30 DU, 4 hPa and 1°C,
respectively.