NIWA has joined forces with Australia’s Bureau of Meteorology 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.
This statement records a sharp rise in sea surface temperatures in the southern Tasman Sea in November, reaching 2 °C or more above average over a wide area.
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."
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.
“The 2017/18 is the only summer on record for New Zealand where the nationwide temperature was more than 2°C above average.”
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.
Special Climate Statement - record warmth in the Tasman Sea, New Zealand and Tasmania (NIWA)
or Special Climate Statements (Australian Government Bureau of Meteorology)
Petra Pearce, NIWA climate scientist
National media team, Bureau of Meteorology
email@example.com or 61 3 9669 4057.