Relationship Between the Momentum and Scalar Fluxes Close to the Ground During the Indian Post-monsoon Period
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Results of a comprehensive study of the characteristics of turbulent transport very close to the ground using micrometeorological eddy-covariance measurements from the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) Integrated Ground Observational Campaign (IGOC) conducted in 2011 at a rural site over the Indian peninsular region are presented. The dataset used in the present study pertains to the morning hours when the convective boundary layer is at its growing phase. A new method, very similar to the traditional quadrant analysis, is introduced to investigate the relationship between the scalar and momentum flux transports by projecting the scalar and momentum flux contours onto the \(u-w\) plane. Cospectral analysis is employed to study the scales of the transporting eddies; it was found that, during very unstable conditions, the scalar and momentum transports are poorly correlated with each other. However, for the near-neutral case, the correlation between the scalar and momentum transports becomes stronger, thus supporting the Reynolds analogy.
KeywordsConvective boundary layer Cospectral analysis Monsoon boundary layer Quadrant analysis Reynolds analogy
Our sincere thanks to Prof B.N.Goswami, Director, IITM for all his constant encouragement and support, and to all the members of the CAIPEEX-IGOC team specially the workshop people for all possible help. We would also like to thank Dr Johannes Laubach for helping us with the technical details and also to Dr Keith McNaughton for providing help and ideas throughout the research. We are also indebted to two anonymous reviewers and the editor, whose comments were very useful in modifying the manuscript.
- Betchov R, Yaglom AM (1971) Comments on the theory of similarity as applied to turbulence in an unstably stratified fluids. Izv. Akad. Nauk SSSR, Ser. Fiz. Atmosf. i Okeana 7: 1270–1279 (829–832 in the Engl. transl. of the journal)Google Scholar
- Chandra K (1938) Instability of fluids heated from below. Proc R Soc A 164:231–242Google Scholar
- Hinze JO (1959) Turbulence. McGraw-Hill, New York, 586 ppGoogle Scholar
- Kaimal JC, Finnigan JJ (1994) Atmospheric boundary layer flows: their structure and measurement. Oxford University Press, New York, 289 ppGoogle Scholar
- Kulkarni JR, Maheskumar RS, Morwal SB, Konwar M, Deshpande CG, Joshi RR, Bhalwankar RV, Pandithurai G, Safai PD, Narkhedkar SG, Dani KK, Nath A, Sapre VV, Puranik PV, Kandalgaonkar S, Mujumdar VR, Khaladkar RM, Vijayakumar R, Prabha TV, Goswami BN (2012) The cloud aerosol interactions and precipitation enhancement experiment (CAIPEEX): overview and preliminary results. Curr Sci 102:413–425Google Scholar
- Tennekes H, Lumley JL (1972) A first course in turbulence. The MIT Press, Cambridge, 300 ppGoogle Scholar