This study presents a new approach to study long-term temperature and urban heat island intensity (UHII) evolution based on the method of time-depended spectroscopy on the example of Moscow megacity. In contrast to standard spectroscopy, this method allows analyzing the changes of the amplitude Fourier spectrum of the time series along the study period. Applying the novel method to the air temperature series for the period of 1977-2020, we demonstrate that ongoing changes of the mean temperature and UHII are accompanied by the changes of their spectra, including the spectral amplitudes corresponding to diurnal, annual and synoptic-scale oscillations. Such changes are complex, often non-linear, and seasonally asymmetric. Steady upward trends are found for summer season, for the spectral amplitudes of diurnal temperature and UHII oscillations, and synoptic-scale UHII oscillations. Spectral amplitudes of annual temperature and UHII oscillations experiences V-shaped dynamics with an increase since 1990th. For UHII such pattern reflects a switch between regimes with wintertime or summertime UHI maximum. Presented results provides an evidence that observed intensification of Moscow's UHI is forced not only by urban growth, but also by changing background meteorological conditions, which are becoming more favorable to UHI appearance in summer and less favorable in winter.

本研究以莫斯科大城市为例，提出了一种基于时间相关光谱法的研究长期温度和城市热岛强度 (UHII) 演变的新方法。与标准光谱学相比，该方法允许分析时间序列的振幅傅立叶光谱在研究期间的变化。将新方法应用于 1977-2020 年期间的气温序列，我们证明了平均温度和 UHII 的持续变化伴随着它们的光谱变化，包括对应于日、年和天气尺度的光谱幅度振荡。这种变化是复杂的，通常是非线性的，而且季节性不对称。对于夏季，昼夜温度和 UHII 振荡的光谱幅度，发现了稳定的上升趋势，和天气尺度的 UHII 振荡。自 1990 年以来，年温度和 UHII 振荡的频谱幅度经历了 V 型动态变化。对于 UHII，这种模式反映了冬季或夏季 UHI 最大值的制度之间的转换。所呈现的结果提供了一个证据，即观察到的莫斯科 UHI 的集约化不仅受到城市发展的影响，而且还受到背景气象条件变化的影响，这些条件在夏季变得更有利于 UHI 出现，而​​在冬季则不太有利。