Preliminary Research on the Microwave Type-Ⅲ Bursts

5 microwave type-Ⅲ bursts have been observed by using the solar radio synchronous observat ional system with high temporal resolution at 1.42GHz, 2.13GHz, 2.84GHz and 4.26GHz in Yunnan Observatory during January 1990 to January 1994.The characteristics (such as durations, frequency drift, associated phenomena)of them are introduced briefly. The time profiles of the event on March 13, 1991 is analyzed in detail.Finally, the conclusion and discussion are given, and the physical parameters of this event are estimated.