Spatial and temporal variation of maximum snow depth and its influencing factors in Heilongjiang Province from 1961 to 2020
As an important type of land cover,the change of snow cover has important feedback and regulation effects on the local hydrological environment and phenological changes. Based on the daily snow depth observa-tion data of 62 meteorological observation stations in Heilongjiang Province from 1961 to 2020,the temporal and spatial variation characteristics of maximum snow depth in Heilongjiang Province and its relationship with at-mospheric circulation,temperature and snowfall factors were analyzed by Mann-Kendall test,empirical orthogo-nal function (EOF),correlation analysis and other methods. The results showed that the average maximum snow depth in Heilongjiang Province from 1961 to 2020 was 16 cm,14 cm,10 cm and 8 cm in autumn,respec-tively. The maximum snow depth in year,winter and spring showed a significant increase trend,with an in-crease rate of 1.40 cm·(10a)-1 (P<0.01),1.51 cm·(10a)-1 (P<0.01),and 0.76 cm·(10a)-1 (P<0.05),with an insignificant increase trend in autumn. From 1961 to 2020,the maximum annual and seasonal maximum snow depth in Heilongjiang Province changed abruptly in the late 20th century and early 21st century,and the maximum snow depth showed an increase in annual variation after the mutation. The maximum snow depth in Heilongjiang Province showed the spatial distribution characteristics of mountains (Greater and Lesser Khingan Mountains,Wanda Mountains) than plains (Songnen Plain and Sanjiang Plain),while the change rate was that the plain was larger than the mountainous area,among which the maximum snow depth in the Songnen Plain in-creased the most. There are two main changes in the maximum snow depth in Heilongjiang Province:east-west reverse type and southeast-northwest reverse type. Temperature,snowfall,polar vortex intensity in the northern hemisphere,and East Asian trough intensity all affected the maximum winter depth in Heilongjiang Province,and the influence of snowfall and polar vortex intensity in the northern hemisphere was greater than that of tem-perature and East Asian trough intensity. As the climate warms,the influence of temperature and the intensity of polar vortexes in the northern hemisphere on the maximum snow depth in winter becomes more pronounced.
maximum snow depthspatial and temporal variationinfluencing factorsHeilongjiang Province
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