CR 75:65-80 (2018)  -  DOI: https://doi.org/10.3354/cr01507

ABSTRACT: Climate oscillations of air and sea-surface temperatures are known to influence surface temperature and precipitation variability. Intraseasonal (4 to 12 mo) and interannual (>12 to 120 mo) variability is investigated using monthly mean temperature data from 4 urban and 3 rural weather stations located in the Kanto region of Japan, during the period January 1973-August 2015. Indices of 6 climate oscillations (El Niño-Southern Oscillation, Indian Ocean Dipole, Quasi-Biennial Oscillation, Arctic Oscillation, Pacific North American Pattern and West Pacific Pattern) known to influence Japan’s climate are investigated using wavelet analysis to identify oscillations in temperature data and climate mode indices at various periods. Continuous wavelet transform analysis shows that temperature variability is more pronounced at the intraseasonal than interannual timescale and urbanisation has no influence on temperature variability. Using the wavelet transform coherence analysis, all climate oscillations except El Niño-Southern Oscillation significantly covary with the temperature at certain periods and years, with the West Pacific Pattern having the highest coherence on average across the whole study period and analysed timescales. On average across the study period, using the multiple linear regression technique, only the Arctic Oscillation and West Pacific Pattern are found to significantly contribute to both intraseasonal and interannual temperature variability.

KEY WORDS: Climate variability · Air temperature · Urban-rural stations · Wavelet analysis · Japan’s climate