APPLICABILITY ASSESSMENT OF ERA5-Land TEMPERATURE DATA IN THE RESEARCH OF THE RELATIONSHIP BETWEEN TREE RINGS AND CLIMATE IN CHINA
In dendrochronological studies,whether ERA5-Land temperature with high spatial resolution and long time series can replace the temperature data from meteorological stations,and the consistency of results using different types of temperature is unknown.We assessed the applicability of ERA5-Land temperature for the study of dendrochronology in China,compared the correlation and numerical difference between the annual and monthly mean temperature data from ERA5-Land and meteorological stations.We also used the publicly published tree-ring chronology for empirical analysis.The results showed that:In different regions,the correlation and numerical difference between temperature data from ERA5-Land and meteorological stations were diversified.On a national scale,there exists a highly significant strong positive correlation between ERA5-Land and station temperature data.Locations with weak or not significantly correlated relationships are mainly concentrated in the Qinghai-Xizang Plateau and Yunnan-Guizhou Plateau.Nationwide,the annual mean temperature of ERA5-Land was,on average,0.82 ℃ lower than the annual average temperature of station data.Points with the greatest degree of lower deviation were mainly concentrated in the Qinghai-Xizang Plateau,while points with the greatest degree of higher deviation were mainly concentrated in mountainous areas at the China's second and third gradient low-altitude mountainous regions.As elevation increased,the positive correlation between the two types of data weakened,and the numerical difference between the two types of data increased.Empirical analysis showed that,if there was a strong correlation between the two types of temperature data,then the correlation results between the tree-ring chronology and ERA5-Land temperature data were almost as same as the correlation results between the tree-ring chronology and meteorological station temperature data.If the correlation between the two types of data was weak and ERA5-Land temperature was lower than meteorological station temperature,the reconstructed historical temperature data based on ERA5-Land temperature would also be lower.Therefore,when using temperature data in dendrochronological studies,it is necessary to comprehensively consider the relevant relationship and numerical differences between temperature from ERA5-Land and meteorological stations,and select appropriate data according to application requirements.
tree ringERA5-Landtemperatureapplicability assessmentempirical analysis
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