Wellington, Jan 25:
A strong marine heatwave is contributing to New Zealand’s unusually hot weather, which is also a reason for the North Island to experience above-normal humidity levels, keeping nighttime temperatures elevated.
“A rapidly intensifying marine heatwave has caused sea surface temperatures to reach a near-record 23-24 Celsius in some coastal areas in late January,” the National Institute of Water and Atmospheric (NIWA) research meteorologist Ben Noll said on Thursday. “It’s striking,” he said.
Since the first big marine heatwave back in 2017 and 2018, they have become commonplace for New Zealand, happening in more summers than not, Noll said, adding this one is really standing out.
Sea surface temperatures around Auckland, New Zealand’s largest city, are borderline tropical, he said.
Marine heatwaves are periods of unusually warm ocean temperatures. They have far-reaching impacts, affecting everything from ecosystems to economics. They also influence weather patterns, priming the environment for tropical cyclones.
“The fact that this marine heatwave is coinciding with the typical annual peak means it’s stacking a 2-3 Celsius anomaly on top of the ocean warming we normally see at this time of the year,” he said, adding swimmers and surfers will have likely noticed the unusually warm waters.
The large warming around the North Island is unusual and does not align with the pattern typically expected during El Nino, said NIWA physical oceanographer Erik Behrens.
2024 has already seen record-breaking temperatures, with places such as Wellington Airport recording its highest January temperature in more than 60 years, and more than 50 locations tracking toward a near-record or record warm month, Behrens said.
