P.S.P. Rao, S. Tiwari, G.A. Momin, P.D. Safai, K. Ali and M.S. Naik, Indian Institute of Tropical Meteorology, Pune.
The concentration of Aitken Nuclei (AN) varied between 400 and 2800 cm-3 with an average of 1090 cm-3.
The diurnal variation of AN showed high concentration during day-time and low concentration during night time indicating the photochemical activity as a source for AN production.
The pH of the rain water varied between 5.63 and 6.02 with an average of 5.73 indicating alkaline rain.
The ionic balance showed the dominance of the cations over the anions resulting in the alkaline pH.
Neutralization factor was found to be high for Ca then for NH4 and Mg.
Percentage contribution of sea salt to rain water was maximum (74%).
11 Higher Dimethyl Sulphide emission in the Bay of Bengal driven by atmospheric convection.
D.M. Shenoy, M. Dileep Kumar, V.V. S.S. Sarma and J. Fernandes, National Institute of Oceanography, Goa.
DMS and DMSP measured during the two-phase experiment of BOBMEX-99 showed high variability in response to intense atmospheric convection.
The atmospheric dynamics appeared to influence oceanic DMS production through the regulation of incident UV.
Sea surface rough conditions in the first phase resulted in higher sea-to-air fluxes of DMS that ranged from ~3 to 41 mmol m-2 d-1 (average=16.3 mmol m-2 d-1) in phase I and from ~2 to 29 mmol m-2 d-1 (average = 9 mmol m-2 d-1) in phase II.
DMS and DMSP in aerosols also showed higher concentrations in phase I than in phase II.
12 Study on the circulation characteristics of monsoon depression during BOBMEX-99: Meso-scale data assimilation.
A.K. Das, U.C. Mohanty, M. Mandal and S.R. Kalsi, Indian Institute of Technology, New Delhi
An attempt was made to study the circulation characteristics of monsoon depression and meso-scale data assimilation during BOBMEX-99. High-resolution meso-scale analysis was prepared by the inclusion of available coastal and ship observations into the coarse-resolution standard data sets viz. NCEP, NCMRWF. Improved analysis was close to the observations and a substantial improvement was seen in the moisture field.