Historical study of the evolution of climate patterns in Puerto Ángel, Oaxaca (1941-1978)

Abstract

This study addresses the climatological data gap in southwestern Mexico by compiling a historical record of temperature and precipitation in Puerto Ángel, Oaxaca. The analysis used processed in situ data from CONAGUA (1941-1978), supplemented with recent satellite-derived atmospheric and sea surface temperature (SST) data to cover periods with sparse records. Methodologically, the research employed principal component analysis (PCA) and descriptive statistics. Sixteen relevant climate change indices for tropical regions were calculated using RClimDex, excluding frost-related phenomena. The satellite time series were decomposed into trend, seasonality, and residuals using the STD method, with analyses primarily conducted in Octave using the M language. Key findings reveal a temperature increase during the 1940s, aligning with national and global patterns. A strong correlation was identified between abundant rainfall and El Niño events, while the coldest years coincided with La Niña. Satellite data show a clear warming trend in both atmospheric temperature and SST from the 2010s onward. This warming is evidenced by the disappearance of historical cold records and an increase in recent maximum temperatures. Consequently, the region experiences more frequent extreme events, evidenced by a high number of intense hurricanes making landfall on the Oaxacan coast since the 1990s, with a notable concentration from the 2010s (e.g., Frank, Carlotta, Barbara, Agatha). The study concludes that the Oaxacan coast is highly sensitive to global and regional climate anomalies.