The Bureau of Meteorology has joined forces with New Zealand's National Institute of Water and Atmospheric Research (NIWA) to issue a joint Special Climate Statement about unusual weather patterns over summer.
This is the first time the two organisations have combined to issue a Special Climate Statement to record unusual climatology in an affected region. Its purpose is to document major events and act as a historical record.
Bureau of Meteorology Senior Climatologist Dr Blair Trewin said the conditions had a major influence on the summer period in Tasmania which had its hottest November-January on record, and in New Zealand which experienced its hottest summer ever.
“We saw particularly warm temperatures in December, when the average sea surface temperature in the southern Tasman Sea was more than 2°C above the 1981–2010 average and 0.6°C above the previous recorded high for any month,” Dr Trewin said.
NIWA climate scientist Petra Pearce described the marine heatwave as “quite remarkable”.
“It spread across the width of the Tasman and resulted in record heat in Tasmania and New Zealand. We would normally see something much more localised but this was very widespread,” Ms Pearce said.
“The 2017–18 is the only summer on record for New Zealand where the nationwide temperature was more than 2°C above average,” she said.
Both scientists said the statement highlights the benefits of shared knowledge and data across agencies and countries. It also provides easy access to data and information in high public demand.
The full Special Climate Statement can be found on the Bureau of Meteorology website.