Thermodynamics and Microphysics Relation During CAIPEEX-I
- 127 Downloads
Influence of the environmental thermodynamics on the microphysics of deep cumulus clouds over different parts of India is studied using in situ airborne observations from the Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) during 2009. This study provides an understanding of the thermodynamics–microphysics relation over the Indian summer-monsoon region. Relatively stronger updraft and turbulence are noted in the pre-monsoon cloud base layers compared to that of the monsoon clouds. It is illustrated from the in situ observations as well as from a microphysical parcel model that the vertical variation of cloud droplet number concentration (CDNC) has a well-defined peak at a certain height above the cloud base. This elevated CDNC peak is found to be connected with the cloud parcel buoyancy and cumulative convective available potential energy (cCAPE). Higher parcel buoyancy above the cloud base of dry pre-monsoon clouds is associated with stronger in-cloud updraft velocity, higher supersaturation and higher droplet number concentration (in addition to aerosol effect). Higher adiabatic fraction and lower entrainment rate are observed in polluted clouds where boundary layer moisture is low, compared to clean clouds. Relative dispersion of droplet size distribution is found to vary concurrently with air mass characteristics and aerosol number concentration observed over different locations during the experiment. Aerosol–precipitation relationships are also investigated from the observation. Maximum reflectivity and rain rates showed a direct link with boundary layer water vapor content rather than with subcloud aerosol number concentration.
The CAIPEEX project and IITM are fully funded by Ministry of Earth Sciences, Government of India, New Delhi.
- Blyth, A., Cooper, W. A., & Jensen, J. B. (1988). A study of the source of entrained air in Montana cumuli. Journal of Atmospheric Science, 45, 3944–3964. https://doi.org/10.1175/1520-0469(1988)045<3944:ASOTSO>2.0.CO;2.CrossRefGoogle Scholar
- Konwar, M., Panicker, A. S., Axisa, D., & Prabha, T. V. (2015). Near-cloud aerosols in monsoon environment and its impact on radiative forcing. Journal of Geophysical Research, 120, 1445–1457.Google Scholar
- Kulkarni, J. R., Maheshkumar, R. S., Morwal, S. B., Padma kumara, B., Konwar, M., Deshpade, C. G., et al. (2012). Cloud aerosol interaction and precipitation enhancement experiment (CAIPEEX): overview and preliminary results. Current Science, 102, 413–425.Google Scholar
- Lu, C., Liu, Y., Yum, S. S., Niu, S., & Endo, S. (2012). A new approach for estimating entrainment rate in cumulus clouds. Geophysical Research Letters, 39, L04802.Google Scholar
- Nair, S., Sanjay, J., Pandithurai, G., Maheskumar, R. S., & Kulkarni, J. R. (2012). On the parameterization of cloud droplet effective radius using CAIPEEX aircraft observations for warm clouds in India. Atmospheric Research, 108, 104–114. https://doi.org/10.1016/j.atmosres.2012.02.002.CrossRefGoogle Scholar
- Patade, S., Prabha, T. V., Axisa, D., Gayatri, K., & Heymsfield, A. (2015). Particle size distribution properties in mixed-phase monsoon clouds from in situ measurements during CAIPEEX. Journal of Geophysical Research: Atmospheres, 120, 10418–10440.Google Scholar
- Twomey, S. (1977). The influence of the pollution in the shortwave albedo of clouds. Journal of the Atmospheric Sciences, 34, 1149–1152. https://doi.org/10.1175/1520-0469(1977)034<1149:TIOPOT>2.0.CO;2.CrossRefGoogle Scholar
- Wang, S., Wang, Q., & Feingold, G. (2003). Turbulence, condensation, and liquid water transport in numerically simulated non-precipitating stratocumulus clouds. Journal of the Atmospheric Sciences, 60, 262–278. https://doi.org/10.1175/1520-0469(2003)060<0262:tcalwt>2.0.co;2.CrossRefGoogle Scholar
- Warren, S. G., Hahn, C. J., London, J., Chervine, R. M., & Jenne, R. L. (1986). Global distribution of total cloud cover and cloud type amounts over land. NCAR Tech. Note NCAR/TN-273 + STR, 29 pp.Google Scholar