Raindrop Particle Size Distribution in the Lower Troposphere

In the Paper, Γ–distribution [n(D)=ADea-λD] parameters (A, a, λ) are obtained by the ratio k1=D1/D2, k2=D2/D3 and linear regression method, where D1, D2 and D3 are diameters for average, root mean square and root mean cube, respectively. The statistical data analysis of raindrop size distribution measured with OAP–2D–P show that the parameter 1 is usually close to 2 obtained from k1 and k2, respectively, so, value between 1 and 2 can be used to approach to it. We have chosen =2, n(D)= AD2e-λD are used to fit into observational raindrop spectra, which is more accuracy than Marshal-Palmer formular (=0). Thus, the regression coefficients (R), characteristic diameters (D1, D2, D3), number concentrations (N), rain rates (I ) and radar echo reflectivity (Z) are all more approximate to observational raindrop spectra than those from the two parameters