Microphysical characteristics of monsoon clouds and cloud sublayers as revealed by the MONEX aircraft observations

The summer monsoon atmosphere was subjected to aerial cloud microphysical measurements by the National Center for Atmospheric Research (NCAR)ʹs Electra as part of the Arabian Sea component of the Summer Monsoon Experiment (SMONEX). The Particle Measuring System (PMS )ʹs probes were mounted on these flights. This study documents vertical profiles and concentration counts of aerosols and precipitation size particles for the flights on 20 and 24 June 1979. These flights were selected because the meteorology associated with them was analyzed in detail by several investigators who were interested in the turbulence flux measurements which were unique to these flights. The samples on 20 June were collected mostly underneath clouds except once within a cloud. In contrast, they were gathered exclusively within clouds on 24 June. The observations on these two days were collected in four different locations over the Arabian Sea when organized convection was presented. s show that the aerosol concentration counts as measured by the ASAS-probe were higher than those expected from measurements in suppressed convective conditions. The ASAS and FSSP readings were nearly constant in the boundary layer. The FSSP readings increased more than ASAS readings with height passing them at elevations greater than 1500 m. Some young clouds with a depth of 1600 m showed maximum updraft values occurring at a certain level (e.g., 1000 m). At this level, a maximum concentration of droplets belonging to a particular size group ( ≈ 15 μm) was found. Thus a positive association was seen between these droplets and the vertical velocity distribution.