The intensive observation period of YMC-CSO2021 completed successfully

The last radiosonde was released on 3/8 18Z last night, and the whole schedule of YMC-CSO2021 was over.

Even in Indonesia, there were various obstacles due to Covid-19, which had a considerable impact on the implementation of observations.

Even in such a difficult situation, the BMKG operation staff continued to do a wonderful job until the end.

This was the first remote observation, and no one had the correct answer and/or experience for the trouble.
We are really grateful that everyone worked hard at each place.

Although we had a lot of trouble, the main target of the cold surge occurred more than usual, and we were able to obtain good data.

From now on, we will analyze the data obtained and investigate the air-sea interactions between cold surges and cold tongue, and the relationship between cold surge and extreme severe weather.

The sea surface temperature (SST) in the South China Sea was 1-2 °C lower than usual, so called “cold tongue” in the SST distribution, and it is suggested that this affected the process of strengthening the cold surge that occurred seven times in two months.

On the contrary, a strong cold surge may have an effect on the development of cold tongue, and it is speculated that positive feedback was working between the two.

In addition, heavy rainfall events accompanied by floods occurred on 1/9 and 2/19 due to cold surges, and elucidation of their formation process is strongly required in Indonesia.