West and eastern Japan are the warmest in January Average temperature nearly three degrees above normal year February 3 18:37
Last month was a record warm winter in various parts of the country. Average temperatures in western and eastern Japan were almost three degrees above normal, with both Januarys being the hottest.
According to the Japan Meteorological Agency, January was warmer than normal in December following last year.
The average temperature in each region is 3.9 degrees higher than normal in Toyooka City, Hyogo Prefecture, 3.4 degrees in Fukui and Tottori, 3.1 degrees in Nagoya, 2.9 degrees in Hiroshima and Fukuoka, 2.6 degrees in Osaka, and 2.4 in Sendai. It was the highest in January at 92 points nationwide, as both were higher. In central Tokyo, it is 1.9 degrees higher than normal.
Looking at the difference from the average yearly average temperature by region, it was 2.8 degrees higher in western Japan and 2.7 degrees higher in eastern Japan.
In northern Japan, it is 1.7 degrees higher than normal, and in Okinawa and Amami it is 1.5 degrees higher.
The amount of snowfall in January was small, and the amount of snowfall by region was 31% of the normal on the Sea of Japan side in northern Japan and 0% on the Sea of Japan side in eastern and western Japan. Has been the least since I started.
Regarding the record warm winter background, the Japan Meteorological Agency says that the westerly wind blowing over the sky meanders to the north side more than usual, making it easier for warm air to flow from the south, but weaker cold from the north .
This situation will continue this month, with temperatures in eastern and western Japan, and Okinawa and Amami expected to be higher than normal.
"Dipole mode phenomenon"
One of the causes of the record warm winter is the “dipole mode phenomenon”. A phenomenon that causes a large difference in the temperature of seawater between the west and east of the Indian Ocean, causing extreme weather in various places.
According to JAMSECT, Takeshi Doi, a researcher at JAMSTEC, the "dipole mode phenomenon" occurs once every few years, and from around May last year, the seawater temperature in the west of the Indian Ocean was higher than that in the east. about it.
The dipole mode phenomenon continued thereafter, and at the peak last November, the sea surface temperature difference reached 2 degrees, making it the largest class ever.
Does it affect meandering winds and rainfall?
In places where the sea temperature is high, updrafts are likely to occur, changing the flow of the "westerly wind" above.
Due to this influence, the westerly winds meandered northward from around Japan in the meantime, making it difficult for cold air to flow in, which is believed to be bringing about a warm winter.
On the other hand, clouds are less likely to form on the eastern side of the Indian Ocean, where the sea temperature is lower, and the amount of rainfall is reduced, which is a factor that prolongs the Australian wildfires.
The dipole mode phenomenon ended last month, but Researcher Doi said, "The seawater temperature is still high and I want you to keep an eye on the Meteorological Agency's information. There are also predictions that will occur again, and we want to monitor them carefully. "