| The variance of the PER in the transition region between the Qinghai-Xizang Plateau and the Loess Plateau during 1961-2010 |
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| DOI：10.7606/j.issn.1000-7601.2018.05.37 |
| Key Words: PER variance warm-drying trend the transition region between the Qinhai-Xizang Plateau and the Loess Plateau |
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| Abstract: |
| Based on data of mean temperature and precipitation during 1961-2010 from 18 weather stations in the transition region between the Qinhai-Xizang plateau and the Loess plateau, the variance of the soil surface aridity index was analyzed and the PER (Potential Evapotranspiration Rate) was computed by Holdridge model. The results indicated that there were 4 humidity provinces (perhumid,humid,subhumid and semiarid) in this area. The spatial distribution of PER showed an increasing trend from the south to the north. The increasing tendency of PER in the perhumid zone, humid zone, subhumid zone and semiarid zone was 0.01·10a-1, 0.04·10a-1,0.06·10a-1 and -0.02·10a-1. There was an obvious warm-drying trend in the humid zone and subhumid zone starting from the 80-90′s, 20th century and the semiarid zone showed a warm-wetting trend concurrently. The temperature increasing and the precipitation decreasing were main influential factors to the PER rising in the eastern area. Although the precipitation increased in the western part, the PER still showed an increasing trend in this area which resulted in the temperature increasing. The temperature increasing resulted in the rising rate of potential evapotranspiration greater than the increasing rate of precipitation and lead to the PER increasing in this region.The increasing trend of potential evapotranspiration and precipitation was very similar in the Xunhua County. The variance of PER in this place was smaller than which in other places and showed a warm-wetting tendency in this area. The ecological environment, water resources and agriculture and animal husbandry production in the transition zone between the Qinhai-Xizang Plateau and the Loess Plateau had been seriously affected by the warm-drying trend. |
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