IITM Publication Highlights
Representation of microphysical processes in cloud-resolving models: Spectral (bin) microphysics versus bulk parameterization
This review article presents a detailed survey of the physical basis and the applications of both bulk microphysics parameterization and SBM. The results obtained from simulations of a wide range of atmospheric phenomena, from tropical cyclones through Arctic clouds using these two approaches are compared. Advantages, disadvantages & lines of future development for these methods are discussed. Read more... (Khain A.P., Beheng K.D., Heymsfield A., Korolev A., Krichak S.O., Levin Z., Pinsky M., Phillips V., Prabha T.V., Teller A., van den Heever S.C., Yano J-I, Revi. of Geophy., May 2015) |
Rethinking Indian monsoon rainfall prediction in the context of recent global warming
Prediction of Indian summer monsoon rainfall (ISMR) is at the heart of tropical climate prediction. Despite enormous progress having been made in predicting ISMR since 1886, the operational forecasts during recent decades (1989-2012) have little skill. This research study shows that, with both dynamical and physical-empirical models, this recent failure is largely due to the models' inability to capture new predictability sources emerging during recent global warming, that is, the development of the central-Pacific El Nino-Southern Oscillation (CP-ENSO), the rapid deepening of the Asian Low and the strengthening of North and South Pacific Highs during boreal spring. A physical-empirical model that captures these new predictors can produce an independent forecast skill of 0.51 for 1989-2012 and a 92-year retrospective forecast skill of 0.64 for 1921-2012. The recent low skills of the dynamical models are attributed to deficiencies in capturing the developing CP-ENSO and anomalous Asian Low. The results reveal a considerable gap between ISMR prediction skill and predictability. Read more... (B.Wang, B.Xiang, J.Li, P.J.Webster, M. Rajeevan, J.Liu and K.J.Ha, Nature Communications, 2015) |
Role of orography in inducing high lightning flash rate at the foothills of Himalaya
Surface electric measurements obtained beneath thunderstorms with almost similar characteristics at a station located close to the Himalayan foothills in northeastern India have been analyzed. Observations suggest many severe thunderstorms occur over this region during late evening/night hours. Moisture conversion at foothills due to radiative cooling at mountaintops during nighttime may be responsible for triggering of such deep convections over Guwahati during the pre-monsoon season. Read more... (S D Pawar, V Gopalakrishnan and P Murugavel, Earth, Planets and Space, Vol. 67 Apr. 2015)) |