Papers by Suneel Vasimalla
Journal of Geophysical Research, 2011
High resolution observations of atmospheric and oceanic variables are carried out at northern Bay... more High resolution observations of atmospheric and oceanic variables are carried out at northern Bay of Bengal from 22nd July to 6th August 2009 on-board ORV Sagar kanya under the Continental Tropical Convergence Zone research/observational programme. Freshening of surface layer by more than 4 psu within 24 hours is observed, which is followed by warming in the surface layer temperature. The heat and salt budget analysis primarily indicates dominant role of advection processes on the evolution of temperature and salinity. The amount of rainfall received at observation site could not explain the observed freshening, thus an extensive analysis using wavelet coherence is done to find out the source of advected fresh water to the observed location. It is found that surface salinity in the northern Bay of Bengal (at 15°N) varies coherently with the rainfall over Ganga-Brahmaputra catchment area on intraseasonal time scale and with lag of about 60 days. Based on above observations, this study hypothesize that the intraseasonal rainfall variation modulates the amount of river discharge, which in turn modulates the salinity over northern Bay of Bengal on intraseasonal time scale. Since surface warming always follows the surface freshening, the time delay between the rainfall over catchment area and freshening at northern Bay of Bengal may explain the post monsoon warming. Importance of atmosphere-ocean coupling in driving the dynamics of the northern bay of Bengal has been clearly brought out in this study.
High resolution observations of atmospheric and oceanic variables are carried out
at northern Bay... more High resolution observations of atmospheric and oceanic variables are carried out
at northern Bay of Bengal from 22nd July to 6th August 2009 on‐board ORV Sagar kanya
under the Continental Tropical Convergence Zone research/observational programme.
Freshening of surface layer by more than 4 psu within 24 hours is observed, which is
followed by warming in the surface layer temperature. The heat and salt budget analysis
primarily indicates dominant role of advection processes on the evolution of temperature
and salinity. The amount of rainfall received at observation site could not explain the
observed freshening, thus an extensive analysis using wavelet coherence is done to find
out the source of advected fresh water to the observed location. It is found that surface
salinity in the northern Bay of Bengal (at 15° N) varies coherently with the rainfall over
Ganga‐Brahmaputra catchment area on intraseasonal time scale and with lag of about
60 days. Based on above observations, this study hypothesize that the intraseasonal rainfall
variation modulates the amount of river discharge, which in turn modulates the salinity
over northern Bay of Bengal on intraseasonal time scale. Since surface warming always
follows the surface freshening, the time delay between the rainfall over catchment area and
freshening at northern Bay of Bengal may explain the post monsoon warming. Importance
of atmosphere‐ocean coupling in driving the dynamics of the northern bay of Bengal
has been clearly brought out in this study.
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Papers by Suneel Vasimalla
at northern Bay of Bengal from 22nd July to 6th August 2009 on‐board ORV Sagar kanya
under the Continental Tropical Convergence Zone research/observational programme.
Freshening of surface layer by more than 4 psu within 24 hours is observed, which is
followed by warming in the surface layer temperature. The heat and salt budget analysis
primarily indicates dominant role of advection processes on the evolution of temperature
and salinity. The amount of rainfall received at observation site could not explain the
observed freshening, thus an extensive analysis using wavelet coherence is done to find
out the source of advected fresh water to the observed location. It is found that surface
salinity in the northern Bay of Bengal (at 15° N) varies coherently with the rainfall over
Ganga‐Brahmaputra catchment area on intraseasonal time scale and with lag of about
60 days. Based on above observations, this study hypothesize that the intraseasonal rainfall
variation modulates the amount of river discharge, which in turn modulates the salinity
over northern Bay of Bengal on intraseasonal time scale. Since surface warming always
follows the surface freshening, the time delay between the rainfall over catchment area and
freshening at northern Bay of Bengal may explain the post monsoon warming. Importance
of atmosphere‐ocean coupling in driving the dynamics of the northern bay of Bengal
has been clearly brought out in this study.