Last summer’s (2010_11) extreme sea temperatures may well still be fresh in the minds of most West Australians as the summer 2010_11 temperatures were the most extreme both temporally and spatially – being described as a ‘marine heat wave’ that coincided with an extremely strong La Niña event and a record strength Leeuwin Current. Following on from last year, there have been reports that water temperatures in and around the Ningaloo Coast feel a little warmer than usual this year as well.
For those of you who feel this way, you can take comfort in the fact that you are not going crazy, because it appears that the sea temperatures are currently above the seasonal average for this time of the year. In fact, sea surface temperature (SSTs) estimates from the National Oceanographic and Atmospheric Administration (NOAA) Coral Reef Watch Program show that this is the third summer in a row that sea temperatures have been above the seasonal average (see figure below) – stations located north of Tantabiddi (Ningaloo) and Coral Bay.
Coral Reef Watch’s SST Anomaly (SST+) is produced by subtracting the long-term mean SST (for that location in that time of year) from the current value, with a positive anomaly meaning that the current SST is warmer than average, and a negative anomaly means it is cooler than average. The graphs above show that in the past three years the SSTs for Ningaloo and Coral Bay have been higher than average from around the October to January period. The red line (summer 2010_11), shows that SSTs rose above seasonal averages a month earlier in September, and that the anomalies were far greater than that recorded in the 2009_10 summer (blue line). In the 2010_11 summer (red line), temperatures continued to rise during January (and in fact remained above average until early May 2011 – resulting in coral bleaching at Ningaloo), whereas temperatures fell to around average during January in the 2009_10 summer (blue line).
In terms of where Ningaloo is tracking this year (2011_12 summer), the green line shows SSTs have been above seasonal averages since mid-October, and while not being as high as last summer (red line), the temperatures during January 2012 still appear to be about 1°C above average and not returning to average temperatures as in the 2009_10 summer (blue line). Moreover, as of 22 January 2012, the Predictive Ocean Atmosphere Model for Australia (POAMA) forecast SSTs to remain between 0.2°C to 0.6°C above average through February 2012 for both Ningaloo and Coral Bay.
For more information on SST data at Ningaloo, click here.