In the article on La Niña 3 years in a row, at the beginning I mentioned that we live in a period of special weather. Because it is a La Niña period 3 years in a row, called triple dip La Nina according to the following article.
Reread Laniya 3 years in a row, part 1/1 Read more
This is divided into 5 sub-issues, now let’s see more.
Six – to Australia In addition to Laniya There are other factors That must be taken into account or not?
When considering rainfall in Australia, the Bureau of Meteorology website notes other phenomena or indices. Indian Ocean Dipole, SAM index, and Madden-Julian oscillation (all three I’ll look for an opportunity to elaborate again. Now let’s summarize for you to read first.)
The Indian Ocean Dipole (IOD) phenomenon has three phases: neutral phase IOD, negative phase IOD, and positive phase IOD.
Between August 16 and August 30, 2022, the IOD was in a negative phase, meaning that winter-spring rainfall in the Southern Hemisphere would be above average for most areas of Australia. (During winter – such spring means June-November 2022)
that means Combining the La Niña effect and negative IOD periods, Australia has more rain than usual.
The SAM Index, or Southern Annular Mode index, was discovered between August 16 and August 30, 2022. The index was neutral. But it is likely to become positive over the next three months (September-October-November 2022). While in New South Wales and eastern Victoria, the humidity is higher than normal.
Madden-Julian Oscillation The Madden-Julian Oscillation, or MJO, is a bipolar oscillation that moves eastward along the equator. At one pole, there will be more rain than usual. While the other pole receives less rain than usual, MJO takes 30-60 days to go around the planet.
Seven – How does La Niña affect North America?
Because during La Niña the surface temperature of the waters in the eastern Pacific is colder than usual. This affects the atmosphere above. and affects the path of the hurricane (jet stream)
for example During La Niña, the polar jet stream moves south. As a result, cold air spreads through Canada and the northern United States.
Meanwhile, parts of the United States (such as the Northwest) are experiencing wetter conditions.
Some areas are drier than usual. (Especially in the south-west) leading to an increased chance of drought and wildfires.
See a diagram showing the impact of La Niña on different areas. in North America, according (Figure 2). Click to see the photo
Eight – How does climate change affect ENSO? [1]
The latest IPCC report, Climate Change 2021: The Physical Science Basis, states that since the 1950s, the extreme levels of El Niño and La Niña conditions have been increasing frequently. Compared to the previous century, the IPCC was unable to decide whether this was due to natural change or climate change.
There is a fascinating aspect. The IPCC climate model predicts that climate change will warm ocean waters and lead to more frequent El Niño conditions. But researchers like Richard Seager, who works at the Lamont-Dougherty Earth Observatory, Lamont-Doherty Earth Observatory of Columbia University in Palisades, New York, noted that the results of observations over the past half century show a trend that is contrary to’ what the IPCC model predicts.
regarding the issue of the comment that the results did not match this prophecy. Some researchers argue that this may be because there is not enough recorded data to show what happened. Or perhaps there is still too much natural variation in the system. As a result, researchers were unable to identify long-term trends.
But at the same time, it is also possible that the IPCC climate model is missing key variables. If this is true, it must be considered important.
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[1] A rare ‘triple’ La Niña climate event looks likely – what does the future hold? Read more
