17 September, 2018 Freeland Journey
The vice president of the institute of Meteorology, Hydrology and Climate Change had explained about the trajectory of the Mangkhut hurricane
According to Mr. Mai Van Khiem - the vice president of the Institute of Meteorology, Hydrology and Climate Change, in terms of science, the movement of hurricanes depends on a number of factors: the currents (the subtropical high pressure), the inertia of the storm, the effects of terrain and friction.
Large waves hit the coastal area of Heng Fa Chuen residential area, Hong Kong
Therein, the currents play an important role in the navigation of the storm and usually, it last for 3 days. This time, when the storm was far away from the Philippines, the subtropical high pressure developed in the south.
If the current tropical high pressure continues as strong as in the early days, based on the calculation model, the storm has a westward direction (i.e., going northwestward towards Vietnam). However, two or three days later, the orbit of the storm changed due to the subtropical high pressure that tended to retreat north.
At that time, all US, Japan, and Europe forecast models updated the atmospheric conditions. According to calculations, the orbit of the hurricane that follows the subtropic of the subtropics is inclined toward the north in comparison with the previous forecast (going north-west rather than northwest).
Hurricanes appearing near each other in the Atlantic region in 2017, including Hurricane Maria, Hurricane Irma, and Hurricane Harvey, are worrying about the relationship between the rise of hurricanes and the intensity of the storm. The larger, more frequent occurrence of climate change and global warming.
Not only in the South China Sea and the Pacific Northwest, typhoons appear simultaneously on most of the world's oceans in mid-September.
The statistics in 11/09 pointed out 9 tropical cyclones (including hurricanes, tropical depressions, and low-pressure areas) are active globally, including hurricanes Florence, Helene, Isaac, Typhoon Paul, and Olivia, super typhoon Mangkhut...
Satellite imagery on September 11th shows a series of tropical cyclones that operate globally in the tropics, including the tropical cyclone Mangkhut in the Pacific Northwest and a very strong storm in the Atlantic
Some researches on the relationship between global warming and storm activity have found that storms are very strong and super typhoons appear more often, especially in the Atlantic.
Even some scientists say that it may be necessary to propose a new level 6 for hurricanes in the Atlantic (currently the highest level is level 5).
The forecast’s difficulty
Storm forecasting technology, especially forecasts of 3 days or more, is based on the model of technology forecasting.
Meanwhile, although there have been significant improvements in typhoon prediction errors in numerical prediction models, the models still have unresolved weaknesses, which is the prediction error of storms location is still a real issue.
Over the past 20 years, there has been almost no improvement in predicting storm intensity.
For predicting Mangkhut's orbit, the prediction of the model before the storm landed in the Philippines was quite consistent.
However, after the Hurricane going through Ludong Peninsula (from 7pm on September 15th), forecasts of the model became scattered, much different.
There is a common trajectory between the orbits, which predicts that the orbits will land on the right, predicting that Mangkhut typhoon will land near Hong Kong and that landings will move more into the land.
Due to the friction with the mainland in time and the longer distance before reaching the Vietnam and China border, Mangkhut typhoons will be more vulnerable before affecting North Vietnam.
As such, the main threat from Mangkhut typhoon to Vietnam will be heavy rains in the North and Thanh Hoa, especially in the northern mountainous provinces.
It can be seen that climate change, along with technological constraints, including the limitations of the forecasting model for the prediction of the trajectory and the intensity of storms, will also make it more difficult for forecasting storms.