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Arid Land Geography ›› 2023, Vol. 46 ›› Issue (5): 700-710.doi: 10.12118/j.issn.1000-6060.2022.395

• Climatology and Hydrology • Previous Articles     Next Articles

Effects of asymmetric warming of daytime and nighttime on the start of growing season on the Mongolian Plateau from 2001 to 2020

ZHANG Gangdong1,2(),BAO Gang1,2(),YUAN Zhihui1,2,WEN Durina1,2   

  1. 1. College of Geographical Science, Inner Mongolia Normal University, Hohhot 010022, Inner Mongolia, China
    2. Inner Mongolia Key Laboratory of Remote Sensing & Geography Information System, Hohhot 010022, Inner Mongolia, China
  • Received:2022-08-13 Revised:2022-09-30 Online:2023-05-25 Published:2023-06-05

Abstract:

Two phenological identification methods, namely, the logistic curve curvature extreme value method and the dynamic threshold method of cumulative NDVI, were used to extract the data based on the normalized difference vegetation index (NDVI) and enhanced vegetation index remote sensing vegetation indices from 2001 to 2020, as well as the highest temperature, the lowest temperature, and precipitation data of 94 meteorological stations in the Mongolian Plateau. The temporal and spatial changes of the Mongolian Plateau’s asymmetric circadian warming and its impact on the start of growing season were analyzed. The research shows the following: (1) The average maximum temperature [0.7 ℃·(10a)-1] and the minimum temperature [0.3 ℃·(10a)-1] in the preseason 6 months (November of the previous year to April of the current year) in the Mongolian Plateau from 2001 to 2020 both showed an upward trend, and the warming rate of the highest temperature was 2.3 times that of the lowest temperature. (2) The asymmetric warming of the preseason day and night has an early effect on the start of growing season; however, compared with the highest temperature, the lowest temperature has a greater impact on the start of growing season, and the impact range is wider. (3) The preseason asymmetrical warming of day and night has different effects on the start of growing season of different vegetation types. The effect of daytime warming on the start of the growing season of shrubs, farmland, and sparse vegetation is more obvious, and the effect of nighttime warming on the start of the growing season of forest and grassland is more obvious, especially in forest areas (25.5%). Studying the effects of daytime and nighttime asymmetric warming on vegetation phenology on the Mongolian Plateau is of great significance to reveal the mechanism of temperature effects on vegetation phenology in spring.

Key words: the highest temperature, the lowest temperature, asymmetric warming, start of growing season, Mongolian Plateau