In this paper, a statistic study of the occurrence rate of spread-F's starting time observed at Hainan station was carried out by use of DPS-4 ionosonde data from February 2002 to December 2007 during the declining phase of the 23rd solar cycle under the conditions of magnetic disturbed and quiet respectively. Based on the spread F observations at Hainan ionosphere sounding station, the starting time statistics of various types of spread F are distinguished into Frequency type Spread F (FSF), Range type Spread F (RSF), Mixed type Spread F (MSF) and Strong range type Spread F (SSF). Results show that both on magnetic disturbed and quiet nights, the total occurrence rate of starting time of MSF is the highest. MSF performs as the most active one, FSF and SSF are secondary ones, and RSF is the least active one. MSF's starting time is mostly around midnight, while FSF's starting time falls into the post-midnight and SSF's starting time is pre-midnight. It is noticed that there is some difference in the starting time of MSF under magnetic disturbed and quiet nights. During magnetic quiet conditions, MSF tends to appear earlier than midnight and on magnetic disturbed nights it appears later. There is some correlation between the starting times of range and strong range types with solar activity. In the years of higher solar activity such as 2002, 2003, the occurrence rate of both types of spread F's starting time is higher in the time period of 20:00LT-22:00LT and 22:00LT-24:00LT under magnetic quiet nights than the one under magnetic disturbed nights, while in the years of lower solar activity such as 2005-2007, the occurrence rate of both types of spread F's starting time is higher in the time period of 00:00LT-02:00LT and 04:00LT-06:00LT during magnetic disturbed nights than the one under magnetic quiet nights. It is hoped that these results in this work is helpful for the study of morphology and mechanism of different type of spread-F.
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