Temperature Dependence of Static Charging in Ice Growing By Riming

E. E. AVILA; G. G. AGUIRRE VARELA; G. CARANTI

JOURNAL OF THE ATMOSPHERIC SCIENCES

AMERICAN METEOROLOGICAL SOCIETY

Año: 1995 vol. 52 p. 4515 - 4522

0022-4928

Charge transfer between colliding ice particles is measured using a wind tunnel inside a cold room. A cylinder growing by riming in a wind tunnel was used as target for collisions between 5 and 6~m~s$^{-1}$ with ice spheres of 100~$\mu$m in diameter. The target temperature was adjusted to simulate different liquid water concentrations. As the target temperature increased, for air temperatures below $-18^\circ$C, initial positive target charging reversed sign to negative; with further temperature increase the charging reversed sign again. These measurements, which are relevant to thunderstorm electrification, were carried out with and without riming and results are compared with other works. A novel approach is presented here suggesting a new pair of variables describing the charging.