Extended monsoon episodes over south Asia: assessing robustness in thermodynamic processes
To address the above and related questions, we perform MSE diagnostics with all the available reanalysis products (ERA-INT, NCEP, JRA-25, MERRA and CFS-R) on composite as well as individual extended monsoon episodes. We identify “robust” signals in thermodynamical processes that provide precursors for the initiation and maintenance of extended break and active conditions over south Asia. Similar budget diagnostics are also performed over the equatorial Indian Ocean, tropical west Pacific and Maritime Continent regions to assess their “linkages” to occurrences of extended episodes over south Asia. Preliminary results suggest robustness in various physical processes that include (1) the temporal evolution of rainfall characteristics over central India; (2) vertical distribution of specific humidity and temperature anomalies; (3) space time evolution of dry (moist) and cold (warm) air advections and (4) cloud-radiative processes. We will discuss the quantitative contributions of individual processes and identify sources of model errors for budget residuals.
Implication of the present study lies in improving CFSv2 skill in prediction of extended monsoon episodes.