Ozone and Related Trace Gases

The analysis on atmospheric ozone has been done using different data sets of varying lengths.

  • 1. There are indications of increasing total ozone at six sites over India except at Varanasi, where a decreasing trend was observed.
  • 2. Ozonesonde data suggests at Pune, there are increasing trends of ozone at 9.7 % per year in the planetary boundary layer.
  • 3. Surface ozone observations also show an increase of 1.45 % per year.

Paleoclimatic Records of Past Monsoons

The analysis on past monsoons is based on proxy data from different sources (tree rings and speleothems).

  • 1. Monsoon fluctuations have been documented from teak trees in Kerala for the past 553 years.
  • 2. The proxy data suggests that monsoon rainfall has been steadily increasing during the Holocene (the past 10000 years).

Regional Climate Change Scenarios

Future regional climate change scenarios are created for the period 1950-2100 by downscaling the simulations of four coupled climate models.

  • 1. The projections indicate significant temperature increases (more than 1.5 °C) over the central and northern parts of India in the mid-term (2031-2060) period. The annual warming range over South Asia land areas is 1.8-3.0 °C by 2060.
  • 2. However, the summer monsoon season precipitation change over India is uncertain not just in magnitude but also in sign.
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