Abstract: Based on monthly ground observation data from 18 meteorological stations in Sanjiangyuan region from 1970 to 2020, the SPEI at different time scales was used as the meteorological drought monitoring index. The climate productivity of forage grass was calculated by stepwise correction method. The temporal and spatial characteristics of meteorological drought and climate productivity in the forage grass growing season in the Sanjiangyuan region were analyzed, and the response of climate productivity to meteorological drought was initially revealed. The results show that: in recent 50 years, meteorological drought of forage grass growing season in the Sanjiangyuan region showed an aggravating trend (P<0.01). The climate gradually changed from humid to arid around 1995, drought occurs mainly in the west, south central and northeast regions; The aridification in the northwest of Sanjiangyuan region is more obvious. The climate productivity of forage grass in the growing season was decreased by 7.38kg·ha⁻¹·y⁻¹(P<0.01). The spatial distribution decreases from northwest to southeast, rising in the west and falling in the east. There is a strong positive correlation between climate productivity of forage grass growth season and SPEI in different time periods in the Sanjiangyuan region. Moreover, with the increase of SPEI forward time, the correlation coefficient increases slightly. The response of forage grass climate productivity to meteorological drought in central and western regions was higher than that in other regions.

Key words: Sanjiangyuan region, Climate productivity, Meteorological drought, SPEI