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Abstract Predictability is an important topic in weather and climate studies. Model-free and model-based quantification of diurnal temperature range (DTR) time series predictability is provided in this paper. Both intrinsic predictability quantified by the permutation entropy and realizable predictability defined by the model's forecasting error are studied on DTR fluctuations. The intrinsic predictability tells us whether there are more predictive structures in DTR fluctuations and to what extent the maximal predictability can be reached. The realizable predictability measures the degree of prediction to which adopted model reaches. Results show that there is a well defined regime-dependent pattern between the intrinsic predictability and the realizable predictability in DTR fluctuations, and both the intrinsic predictability and the realizable predictability in DTR fluctuations over China are overall South–North (with the dividing line around the latitude of 37°N and almost along the Yellow River, and south and north to this line are called southern China and northern China in this study) asymmetric with higher predictability in southern China and weaker predictability in northern China. This South–North contrasting predictability behavior is closely related to the DTR's South–North asymmetric multi-fractal behavior. Highlights • Both intrinsic and realizable predictability are studied on DTR fluctuations. • Well defined regime-dependent relation between two predictabilities exists. • Overall South–North asymmetric predictability is revealed in DTR over China. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the variability of daily temperature in the Yangtze River Delta (YRD) for the period 1958–2007 was investigated by selecting three typical temperature variables (daily minimum, mean and maximum temperatures) and the diurnal temperature range (DTR). Three variability patterns of daily mean temperature and two variability patterns of daily minimum and maximum temperatures were first classed, and then statistical properties of three temperature variables in 1958–1985 and 1986–2007 were analyzed. After that, temporal trends of three temperature variables and DTR were detected. Finally, the impacts of urbanization on the variability of daily temperature were investigated. Results indicate that: (1) daily mean temperature shows more complex variability than daily minimum and maximum temperatures; (2) in 1986–2007 three temperature variables have bigger mean values but smaller C v (coefficient of variance) values, and are more close to normal probability distribution; (3) three temperature variables show positive trends in 1986–2007, and the increase of daily mean temperature is more due to the increase of daily minimum temperature in the northern YRD but due to daily maximum temperature in the mid and southern YRD; (4) in the mid and southern YRD, daily maximum temperature has bigger increasing magnitude than daily minimum temperature in 1986–2007, causing positive trend of DTR; and (5) rapid urbanization causes normal distribution of three temperature variables, and notably increasing magnitude of daily temperature and DTR in 1986–2007 at the lower reaches of the Yangtze River and the Hangzhou Bay. [Copyright &y& Elsevier]