Readers may be aware of the “Cold Blob” which is moving across the northern Pacific Ocean. In this post I shall show sea surface temperature anomalies, and currents, in all of the world’s oceans, as shown by nullschool.
This is the colour scale for all figures, from -6C to +6C. Zero anomaly is black.
The Arctic Ocean
The Southern Ocean
Note the large area of sea ice around Antarctica (black) surrounded by a ring of below average SSTs, with another ring of swirling eddies of warmer SSTs. Note also the cold blob just below south-western Australia which is working its way east.
The Atlantic Ocean
The North Atlantic is predominantly unusually warm- especially the Gulf Stream. However the South Atlantic is largely covered by a very large pool of cold water.
The Indian Ocean
The Indian Ocean Dipole between the west and the east is plain to see. Note the colder than normal SSTs near south-western Australia which have led to some unusually cold land temperatures this winter and spring.
The Pacific Ocean
The El Nino has ended and La Nina appears to be building as the surge of cold water moves west along the Equator. Note the cold blobs in the North Pacific, and less well defined in the South Pacific. Note also the high SSTs near South America and around the International Date Line at 30 degrees North.
Note there are large areas of above and below normal SSTs in all ocean basins except the Arctic, where sea ice cover tends to hide water temperature below. The Arctic ocean atmospheric temperature anomalies have recently shot up to record highs.
I now turn to the seas close to Australia.
Waters around the northern, north-western, and eastern coasts of Australia are generally 1.0 to 1.8C above normal. This includes the area of the Great Barrier Reef. The East Australian Current runs down the east coast and can be seen as a warm tongue spilling into the Tasman Sea. (This is what led to the ABC’s reports about high temperatures in the Tasman Sea.) But the Tasman Sea has several eddies of cold and warm water. Note also the cold area to the south of Western Australia, and the cool area just to the east of Tasmania.
Warm waters around northern Australia are likely to generate extra rainfall and probably cyclones, and a strong gradient between north and south will likely lead to strong weather changes and storms.
Conclusion: Once again, the difference between the Northern and Southern Hemispheres shows itself in sea temperatures. Apart from the cold blob in the northern Pacific, Northern Hemisphere oceans are predominantly warmer than usual, while those of the Southern Hemisphere have large regions of both warmer and cooler water. There is a very large cold blob in the South Atlantic, and another surrounding Antarctica. Ocean currents constantly move thermal energy around, releasing it by radiation and evaporation mainly, and governing land temperatures hundreds of kilometres away.
The next six months should be interesting.