Two hundred years of rainfall in Barcelona: how its irregularity has evolved and autumn rain's role

What is it about?

This study looks at how the irregularity of rainfall in the series has changed over time using the idea of rainfall disparity. We also consider the WeMOi atmospheric parameter to help understand the possible causes of these irregularities. This approach gives us a clearer picture of rainfall fluctuations. Additionally, we closely examine autumn rainfall, which has historically played a significant role in the total annual rainfall. We found a noticeable trend of increasing disparity in autumn rainfall. Recent years, especially 2021, 2022, and 2023, have shown a pattern of low rainfall, making them some of the driest years since 1835. The last two autumns, in particular, rank among the driest 5% of the series.

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Photo by American Jael on Unsplash

Photo by American Jael on Unsplash

Why is it important?

This article is significant because it utilizes a remarkable dataset covering 238 years, enabling a comprehensive analysis of long-term rainfall trends. The study identifies extremely dry years in the early 19th century, attributed to the coincidence of astronomical and geological factors. Specifically, this period coincided with low solar activity known as the Dalton Minimum (1790–1830) and the eruption of the Tambora volcano in Indonesia, which resulted in the so-called 'year without a summer' in 1816. These events led to changes in atmospheric circulation that caused a notable decrease in precipitation across southern Europe. Furthermore, the article highlights the recent and ongoing decline in precipitation in the region, which may be influenced by anthropogenic climate change. By examining both historical and contemporary factors, this study provides valuable insights into how climate variability has evolved over nearly two and a half centuries, enhancing our understanding of both past and present climatic impacts.