Slower decay of landfalling hurricanes in a warming world

• Published in: Nature
• Main Authors: Lin Li, Pinaki Chakraborty
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Research 2020
• Subjects: North Atlantic
• Online Access: http://id.nii.ac.jp/1394/00001670/; https://oist.repo.nii.ac.jp/?action=repository_uri&item_id=1851; https://oist.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1851&item_no=1&attribute_id=22&file_no=1

When a hurricane strikes land, the destruction of life and property is largely confined to a narrow coastal area. This is because hurricanes are fueled by the moisture from the ocean, with the implication that hurricane intensity decays rapidly after striking land. In contrast to the effect of a warming climate on hurricane intensification, many aspects of which are fairly well understood, little is known of the corresponding effect on hurricane decay. Here we analyze intensity data for North Atlantic landfalling hurricanes over the past 50 years and show that hurricanes decay has slowed, in direct proportion to a contemporaneous rise in the sea-surface temperature. Thus, in the late 1960s, a typical hurricane lost ∼75% of its intensity in the first day past landfall; now, the corresponding decay is only ∼50%. We also show, using computational simulations, that warmer sea surface temperatures induce a slower decay by increasing the stock of moisture which a hurricane carries as it hits land. This ‘storm moisture’ constitutes a source of heat that is not considered in theoretical models of decay. Additionally, we show that climate-modulated changes in hurricane tracks contribute to the increasingly slow decay. Our findings suggest that as the world continues to warm, the destructive power of hurricanes will extend progressively farther inland.