Abstract: Based on the data of the daily precipitation and daily maximum air temperature in 1971-2000 in three national benchmark stations in Tangshan,the Y drought index was calculated in consideration of three factors,including precipitation in recent period,the soil moisture preceding rainfall and air temperature. The drought severity degree was determined. The Y drought index was compared with the soil humidity drought index and precipitation anomaly percent at the same time. The verifications of Y drought index had done with the soil humidity data in the spring of 2006 and 2007. The results showed that the Y drought index was consistent with the soil drought index. The Y drought index could be used in the drought monitoring to replace the soil drought index.

Key words: Drought index, Drought index, Drought severity degree, Soil moisture, Spring drought monitoring