The 20^th century has been witnessed with the rise of global temperature due to CO₂ emission since the industrial revolution. The global warming is observed around the world, and the governments take measures to reduce CO₂ emission to combat the rise of temperature. The temperature profile has been mainly modelled at global level. Yet, it necessarily models the temperature in cities because each city would have its own feature. Among various models to fit or simulate the temperature, the application of random walk model is rare. In this study, we used the random walk model to fit the temperature of the 21^th century in 49 European capitals not only because the industrial revolution first appeared in Europe but also European governments commit and endorse the Paris Agreement. First, the yearly temperature was simplified as increase (+1) or decrease (–1) in comparison with previous year, whose addition in the 20^th century in each of 49 European capitals construct a step-typed curve. Second, random walk model was used to fit these step-typed curves with the least squared method. Third, the widely used CRUTEM3 temperature in the 20^th century in each of 49 European capitals was directly fitted using random walk. The results show that random walk can fit the step-typed curves and CRUTEM3 temperature.

20^世纪见证了工业革命以来由于CO ₂排放导致全球气温上升。全球变暖现象在世界范围内都存在，各国政府采取措施减少CO ₂排放以应对气温上升。温度剖面主要在全球范围内建模。然而，它必须模拟城市的温度，因为每个城市都有自己的特点。在各种拟合或模拟温度的模型中，随机游走模型的应用很少见。在本研究中，我们使用随机游走模型来拟合 21^日世纪 49 个欧洲国家的首都，不仅因为工业革命首先出现在欧洲，而且欧洲各国政府承诺并认可了《巴黎协定》。首先，将年温度简化为与上年相比增加（+1）或减少（-1），其在 20世纪的 49^个欧洲国家首都中的每一个都构成了阶梯式曲线。其次，随机游走模型被用来用最小二乘法拟合这些阶梯式曲线。第三，使用随机游走直接拟合了 20 世纪欧洲 49 个首都中^广泛使用的 CRUTEM3 温度。结果表明，随机游走可以拟合阶梯型曲线和CRUTEM3温度。