Impacts of climate change on the relationship between snowfall and newly-added snow depth in Jilin Province
Snowfall is a common form of precipitation in mid-high latitudes during winter.Intense snowfall can lead to thick snow cover and trigger snow disasters,so it is one of the significant natural hazards in northern Chi-na and the Tibetan Plateau during the winter season.Past studies on snow density in snow-covered areas mainly focused on the overall snow cover condition over a certain period,but few focused on the newly-added snowfall.In this study,the observation data including precipitation,snow depth,temperature,wind speed,and weather phenomena from 50 meteorological stations in Jilin Province from 1961 to 2021 are utilized.After rigorous data verification and preliminary calculations,the sequence of newly-added snow depth of moderate to heavy snow-fall events is obtained.Furthermore,the relationship between snowfall and newly-added snow depth is investi-gated,and then the causes of this relationship are analyzed.The results show that for the moderate to heavy snowfall events in Jilin Province,there is a correlation coefficient of 0.78 between snowfall(S)and newly-add-ed snow depth(D),which has passed the significance testat99.9%confidence level.The average ratio of newly-added snow depth to snowfall(Rds)is 0.96 cm·mm-1.The Rds is small in western areas and large in eastern ar-eas.In most stations of western areas,the multi-year average Rds ranges from 0.82 to 0.99 cm·mm-1.In most parts of Changchun City and Siping City,and the entire Liaoyuan City,the Rds is from 1.01 to 1.10 cm·mm-1.For the southern and most central-eastern areas of Jilin Province,the Rds is between 1.11 cm·mm-1 and 1.25 cm·mm-1.The Rds exhibits distinct monthly,annual and decadal variations.The monthly variations follow an asymmetric parabolic pattern,with December and January being the peak periods.The multi-year average Rds ranges from 1.22 to 1.24 cm·mm-1.The Rds is lower during November and February(from 1.07 to 1.10 cm·mm-1),and is the lowest in October and April with an average of 0.89 cm·mm-1.Over the past 60 years,the Rds has decreased with a rate of-0.01 cm·mm-1·(10a)-1,which has passed the significance test at the 95%con-fidence level.The Rds is relatively greater(1.16 cm·mm-1)in the 1970s and 1980s,slightly lower(from 1.13 to 1.14 cm·mm-1)in the 1960s and 2000s,and the lowest in the 1990s(1.09 cm·mm-1)and 2010s(1.05 cm·mm-1).In the past 60 years,the Rds variation in December has contributed the greatest to the Rds variation in the whole snow season in Jilin Province.The monthly average difference of Rds between 1970s and 2010s(typi-cal years)is larger than that between 1961-1990 and 1991-2020(standard climatic periods).Moreover,most months during the snow season have played an important role in the variations of the average Rds in typical years.The decrease of Rds in Jilin Province over the past 60 years has shown consistent spatial variation.The range and magnitude of the Rds decrease is larger in typical years than in the standard climatic periods.The Rds on snowfall days exhibits a clear negative correlation with temperature.Within the temperature range of-12℃to 0℃,the Rds significantly decreases as temperature rises.Global warming,increased precipitation,and re-duced wind speed are direct factors contributing to the interdecadal variations of the relationship between snow-fall and newly-added snow depth.Understanding the relationship between snowfall and newly-added snow depth is important in comprehending the characteristics and formation mechanisms of snowfall and snow cover in mid-high latitudes of Northeast Asia.We hope the results may provide some valuable insights for predicting snow depth,snowfall parameterization,and snow disaster mitigation.
NETL
NSTL
万方数据
