Rainfall at Hilo, Hawaii1

[摘要] Rainfall at Hilo, Hawaii was studied by the character of inversion height and strength, which has a strong relation with movement of the upper cyclone. The electric field, satellite pictures, and general meteorological parameters such as upper wind, temperature and humidity profiles obtained by radiosonde were referred to for the rain classification. August rain was studied in detail as typical of trade-wind rain, and for another month, rain with ice phasewas studied to compare with the rainfall pattern from warm rain.The types of rain are subdivided into: a) morning and evening rain, caused by land and sea breezes when the inversion is low; b) intense, all-day rain, occurring when the inversion is high; c) weak but continuous rain, occurring when there are double inversions. There is no rain when the inversion height is less than 1.7km.Winter time cool rain is also studied. It is characterized by long-lasting, heavy rainfalls accompanied by high electrical activity and usually by lightning. This contrasts with warm rain, heavy but short-lasting falls with weak, negative electricity. It seems that although the presence of ice crystals does not contribute to high rainfall intensity from deep cloud, it is important for the generation of high electrical activity and for maintaining heavy rain.

[学科分类] 大气科学