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Decadal Difference in Influential Factors for Interannual Variations of Winter Tibetan Plateau Snow

2022; RELX Group (Netherlands); Linguagem: Inglês

10.2139/ssrn.4309436

1556-5068

Changyan Zhou, Ping Zhao, Ge Liu, An Xiao, Haohui Yu,

Remote Sensing and Land Use

Using the observational snow cover day (SCD) data at meteorological stations, the NCEP-NCAR atmospheric reanalysis, and the Hadley Centre Sea Ice and Sea Surface Temperature dataset during 1973-2019, we investigate the influential factors for interannual variations of winter snow over the central-eastern Tibetan Plateau (hereafter called the TP) and their decadal difference. The results show that the winter TP SCD exhibits a decadal shift from a positive phase to a negative phase around the late 1990s. Concurrent with this decadal shift, the dominant influential factor for the interannual variability of the winter TP SCD has an alternation from the tropical ocean to the Arctic signal. Before the late 1990s, the winter TP SCD is closely related with the synergistic effects from the tropical central-eastern Pacific (TCEP) SST and the tropical eastern Indian Ocean (TEIO) along the tropical ocean-TP path, while it is closely related with the AO along the Arctic-TP path since the late 1990s. Different from the significant weakening of the interannual fluctuation of the TEIO and TCEP SST, the interannual fluctuation of the AO show a remarkably strengthening trend in recent 20 years. The strengthened Arctic signal could exert a strong influence on the TP SCD through a wave train that goes along the path from the Greenland and adjacent areas to the TP via the extratropical Atlantic Ocean and the middle-high latitudes of Eurasia. Thus the opposite trends in the fluctuation intensities of the El Ninõ-Southern Oscillation (ENSO) and AO on the interannual timescale may lead to a larger contribution of the Arctic signal to the interannual variability of the TP climate in the recent 20 years.Using the observational snow cover day (SCD) data at meteorological stations, the NCEP-NCAR atmospheric reanalysis, and the Hadley Centre Sea Ice and Sea Surface Temperature dataset during 1973-2019, we investigate the influential factors for interannual variations of winter snow over the central-eastern Tibetan Plateau (hereafter called the TP) and their decadal difference. The results show that the winter TP SCD exhibits a decadal shift from a positive phase to a negative phase around the late 1990s. Concurrent with this decadal shift, the dominant influential factor for the interannual variability of the winter TP SCD has an alternation from the tropical ocean to the Arctic signal. Before the late 1990s, the winter TP SCD is closely related with the synergistic effects from the tropical central-eastern Pacific (TCEP) SST and the tropical eastern Indian Ocean (TEIO) along the tropical ocean-TP path, while it is closely related with the AO along the Arctic-TP path since the late 1990s. Different from the significant weakening of the interannual fluctuation of the TEIO and TCEP SST, the interannual fluctuation of the AO show a remarkably strengthening trend in recent 20 years. The strengthened Arctic signal could exert a strong influence on the TP SCD through a wave train that goes along the path from the Greenland and adjacent areas to the TP via the extratropical Atlantic Ocean and the middle-high latitudes of Eurasia. Thus the opposite trends in the fluctuation intensities of the El Ninõ-Southern Oscillation (ENSO) and AO on the interannual timescale may lead to a larger contribution of the Arctic signal to the interannual variability of the TP climate in the recent 20 years.