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Analysis of temporal and spatial characteristics of growing season drought in Liaoning Province based on standardized precipitation-evapotranspiration index.

ZHANG Yun-fu1*, FANG Yi-he2, GONG Qiang3#br#   

  1. (1 Liaoning Provincial Meteorological Service Center, Shenyang 110166, China; 2School of Atmospheric Sciences, Nanjing University of Information Science & Technology, Nanjing 210044, China; 3Shenyang Regional Climate Center, Shenyang 110166, China).
  • Online:2017-01-10 Published:2017-01-10

Abstract: Based on the monthly precipitation and temperature data from 50 meteorological stations during 1961-2015, the temporal and spatial characteristics of drought in growing season in Liaoning Province were analyzed using the standardized precipitation-evapotranspiration index (SPEI), linear trend analysis, MannKendall abrupt test and empirical orthogonal function (EOF). The results showed that the SPEI significantly decreased with a rate of 0.1310 a-1 and the overall trend of drought increased from 1961 to 2015 in Liaoning Province. The drought intensity varied with time, i.e., it was gradually weakened in the 1960s and 1970s, gradually strengthened at the beginning of 1980s, then continuously decreased from the early 1980s to midlate 1990s and finally strengthened continuously from the late 1990s to 2015. In 1996, the SPEI for the whole province abruptly decreased with a sudden enhancement in the drought intensity. Especially in 2000, the largest range of drought in recent 55 years occurred at 47 meteorological stations, accounting for 94% of the total area. The drought rates were 92% and 88% in 1999 and 2014, respectively. There were three major modes for the spatial distribution of SPEI, i.e., the regional consistent type, the reverse type between southeast and northwest and the reverse type between central and other regions. The regional consistent type with high values included coastal Huludao, Jinzhou, Shenyang and Anshan, which indicated that these areas were most sensitive to drought. There was a significant decreasing tendency in the time coefficient of the first mode. In the reverse type between southeast and northwest, the zero value line of space coefficient located at the central Liaoning exhibiting northeastsouthwest. The space coefficient of the west and the north of Liaoning located to the west of zero value line was negative, but the space coefficient of the regions in the east of zero value line was positive. There was no clear tendency in the time coefficient of the second mode. In the reverse type between the central, Bohai coast and other-regions, the space coefficient was positive in southeast and west regions, but negative in other-regions, showing no significant tendency in the time coefficient.