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Journal of Agriculture ›› 2016, Vol. 6 ›› Issue (10): 92-96.doi: 10.11923/j.issn.2095-4050.cjas16060010

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Variation Characteristics of the Extreme Precipitation Threshold and the Extreme Precipitation Days in Nansi Lake Area During 1981-2014

  

  • Received:2016-06-13 Revised:2016-09-15 Accepted:2016-09-20 Online:2016-11-01 Published:2016-11-01

Abstract: The paper aims to study characteristics of the extreme precipitation in Nansi Lake. Using the daily precipitation data of 9 weather stations in Nansi Lake during 1981-2014, the variation characteristics of the extreme precipitation threshold and the extreme precipitation days were analyzed. The results showed that: (1) for extreme precipitation events of the 90th percent, 95th percent and the 99th percent, the average precipitation threshold was 24.7 mm, 40.0 mm and 80.2 mm, respectively; (2) the northern precipitation threshold was larger than the southern one in Nansi Lake area, as the eastern one was larger than the western one; the spatial distribution of the extremely heavy precipitation threshold was similar to the distribution of the amount of annual precipitation; (3) the average annual extreme precipitation of Nansi Lake area was stronger in northeastern and northern Nansi, and was weaker in southern and southwestern Nansi, the distribution was relatively similar to the precipitation climate average distribution of Nansi Lake area, reflecting that the contribution of the extreme precipitation was big to precipitation; (4) the extreme precipitation days in Nansi Lake was 3.08-3.56 days per year, showed that the site with bigger extreme precipitation threshold had less extreme precipitation days, the correlation coefficient reached - 0.893; (5) the contribution of the extreme precipitation to the total precipitation in Nansi Lake was 34.2%-37.7%, and the distribution of average annual extreme precipitation intensity was similar to the distribution of extreme precipitation threshold, showed that places with big threshold had high precipitation intensity and disaster risk; (6) the number of extreme precipitation days on average was 23.5 days, and rose at a rate of 4.5 d/10 a; (7) the total extreme precipitation days in Nansi Lake had mutations in the mid-and late 1980s, and had 2 oscillation periods of 2 years and 16 years.