South Asian monsoon getting more complex

HIMALAYAN NEWS SERVICE

KATHMDANDU: The seasonal cycle of solar heating warms the land regions surrounding South and Southeast Asia faster than the adjoining oceans, owing to differences in heat capacity, and develops a large-scale surface temperature gradient, says a new study published in Nature today.

“With projected increases in population and pressure on food security, understanding how the monsoon will change in the future is a fundamental challenge for climate science,” the research conducted by Andrew G Turner and H. Anamalai concluded.

The vagaries of South Asian summer monsoon rainfall on short and long timescales impact the lives of more than one billion people.

Further the researchers said, “This results in the formation of a surface heat low over northern India in late spring; the north-south pressure gradient then induces a cross-equatorial surface flow and return flow aloft.”

The scientists claimed that the dynamics and thermodynamics of the South Asian monsoon go beyond this simple land-sea breeze argument.

According to the new findings, “The Himalaya and Tibetan Plateau ensure that sensible heating during boreal spring occurs aloft, meaning that the large-scale meridional temperature gradient exists not just at the surface but over significant depth in the troposphere — the lowest portion of earth’s atmosphere, anchoring the monsoon onset and intensity.”

The researchers have said that the dust particles known as aerosols which are increasing in South Asia due to rapid industrialisation and population increase have also further have created problem in predicting the South Asian monsoon as it play key role for rainfall in this reason.