Influence of ENSO and the urban heat island on climate variation in a growing city of the western Mexico

Abstract

To understand climate change in the local context, it is necessary to analyse three factors in the territories; 1) how temperature and precipitation have varied over time, 2) if there is an association with the natural variation of the planet, for example with the El Niño-Southern Oscillation (ENSO) phenomenon, and 3) if the variations could be related to human actions that directly alter the climate, such as gas emissions into the atmosphere and deforestation. Understanding how these three factors interact, what impacts they have caused on the territory and how they will behave in future scenarios, allows us to think about development planning strategies that seek to adapt human communities to future climate conditions. This study addresses climate change in the City of Tepic, analysing the interannual variation of temperature and precipitation, its association with the ENSO phenomenon and the possible relationship with the urban heat island, contrasting two time periods; 1980-1999 and 2000-2018. The results showed a generalised increase of +1 ºC between periods, decrease of precipitation up to -6% the summer months and increase up to +20% the autumn months. The influence of ENSO on temperature variation increased from 10% to 20% in the most recent period, and its influence on precipitation variation decreased from 17% to 8%, respectively. On the other hand, the heat island increased its extension by more than 60% and its intensity by about 8 degrees between the periods analysed. The differences between periods are discussed descriptively in relation to the doubling of the area of urban use, population, atmospheric emissions and the loss of 30% of the forests in the areas adjacent to the city.