Changes in surface air temperature in the spring can have significant impacts on human health and have significant socio-economic consequences. Therefore, it is of great interest to understand and predict variations in spring temperatures. However, the dynamics and predictability of East Asian temperatures in the Boreal Spring are more difficult than those in other seasons. Part of the difficulty is due to the existence of what is known as the Spring Predictability Barrier, a phenomenon whereby ENSO-based predictive competence declines rapidly during the Boreal Spring.
“East Asia experienced an unusually warm spring in 2018, when unusually high surface air temperatures were recorded over large areas of Asia, such as northern China, southern China and Japan, “says Dr Kaiqiang Deng, a climatology researcher who works with Professor Song Yang of the School of Atmospheric Sciences, Sun Yat-sen University, and the first author of a paper recently published in Atmospheric and Oceanic Science Letters.
“The intensity of ENSO typically peaks during the boreal fall and winter and tends to decrease dramatically during the boreal spring, reducing the predictability of climate and weather in East Asia during of this period. However, the ENSO signal in 2017/18 was weak, so it is interesting to explore if there were any other earlier signals (besides ENSO) that could have been applied to predict the heat of Asia from East in the spring of 2018, ”says Dr Deng.
Dr Deng and colleagues studied spatiotemporal patterns of record temperatures in East Asia in spring 2018 based on ERA-Interim reanalysis data. Their research has linked the extreme heat of East Asia in the Boreal Spring to North Atlantic SST anomalies.
The results indicated that the tripolar mode of the North Atlantic SST anomalies can trigger anomalous Rossby wave trains over the North Atlantic and Eurasia by modulating the baroclinic instability of the North Atlantic, which then propagate eastwards and induce an abnormally high pressure and anticyclonic circulation over East Asia, leading to downward movement, reduced precipitation and increased solar radiation at the surface, which have been favorable record heat in East Asia in spring 2018.
“The seasonal memory of the tripolar North Atlantic SST mode from the previous winter to the following spring may provide useful implications for seasonal forecasting of weather and climate in East Asia,” said Dr Deng. . “In the future, we would like to build a statistical forecasting model to improve the sub-seasonal to seasonal forecast for the spring climate of East Asia.”
Eurasian atmospheric circulation anomalies may persist from winter to the following spring
Kaiqiang Deng et al, Unprecedented warming of East Asia in spring 2018 linked to the tripolar SST mode of the North Atlantic, Atmospheric and Oceanic Science Letters (2019). DOI: 10.1080 / 16742834.2019.1605807
Quote: East Asian hot spring linked to the Atlantic Sea surface temperature anomaly (July 1, 2019, retrieved October 4, 2021 from https://phys.org/news/2019-07-east- asian-hot-linked-atlantic.html
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