Abstract: Based on daily ordinal observation data of the temperature from 52 stations in Liaoning Province over the recent 50 years (1961-2007),the spatio-temporal evolvement characteristics of frostless period in Liaoning Province were investigated by using GIS technique,climatic trend rate and abrupt change analysis methods. Results demonstrated that in terms of regional average,frostless period initial date ordinal (FLPIDO)moved up 2.2 days per 10 years,with a climate abrupt change happened around 1989,and frostless period ending date ordinal (FLPEDO)and duration (FLPD)postponed and increased significantly by 1.9 days and 3.9 days per 10 years,respectively. Abrupt change for FLPEDO happened around 1975. FLPD increased significantly with rate of 3 to 4 days per 10 years in most past of Liaoning. Second,there were significant difference for different periods' average (period A:1961-1990;period B:1971-2000). The FLPIDO in period B was earlier and FLPEDO was later and FLPD was longer than that of in period A. Third,the large and small values of area of FLPD were larger in 1970s than that of in 1960s in the GIS map,and the large value area enlarged continue but the small value area shrank in 1980s,and there was no significant difference between 1980s and 1990s,and the large value areas covered most of Liaoning and small value areas shrank remarkably after 2000.

Key words: GIS technique, GIS technique, Liaoning, Frostless period, Spatio-temporal evolvement characteristics