Our environment is subject to numerous weather phenomena, one of which is the ‘Azores High.’ A study has recently highlighted an unusually large Azores High that has caused unusually dry conditions across the western Mediterranean region, affecting mainly the Iberian Peninsula, home to Spain and Portugal.
Understanding the Azores High
The Azores High is a subtropical high-pressure system that usually becomes prominent over the eastern subtropical North Atlantic and western Europe in winter. Its formation can be attributed to the descent of dry air aloft in the subtropics, aligning with the downward portion of the Hadley Circulation.
The Role of the Hadley Circulation
Hadley Cells are low-latitude overturning circulations, marked by rising air at the equator and sinking air around 30° latitude. These cells are responsible for the tropical trade winds and heavily influence weather patterns in low-latitude regions.
Impact of the Azores High
Due to the Azores High, a consistent decrease in annual rainfall in the Iberian Peninsula has been recorded at a rate of 5-10 millimeters per year per decade during the second half of the 20th century. The trend is expected to continue, with a predicted 10-20% drop in winter rainfall by the end of the 21st century. This decrease in precipitation could severely impact the agriculture of the Iberian region, making it one of the most vulnerable regions in Europe. The study projects a significant decrease in olive production and a shrinking cultivation area in grape-growing regions due to severe water shortages.
Expansion of Azores High
The expansion of the Azores High is primarily driven by external climate forces. Of these forces, the most significant contributor in the industrial era has been atmospheric greenhouse gas concentrations. Researchers traced the atmospheric conditions since the industrial era, revealing an emergence of Azores High expansion post-1850 and a significant strengthening in the 20th century, aligned with human-induced warming.
UPSC Civil Services Examination: Past Years’ Questions
For understanding the geographical aspects related to weather phenomena like the Azores High, we can refer to some past years’ questions from the UPSC Civil Services Examination.
In the 2019 examination, a question was asked about the countries bordering various seas. The pairs (Adriatic Sea – Albania, Caspian Sea – Kazakhstan, and Mediterranean Sea – Morocco) were correctly matched, while the other pairs (Black Sea – Croatia, Red Sea – Syria) were not.
In the 2017 examination, a question was asked about the countries bordering the Mediterranean Sea – the correct answer included Lebanon and Syria.