14:30 〜 14:45
[AAS01-04] 成田空港における乱気流の実事例の数値気象モデルによる再現
キーワード：乱流、数値気象モデル、突風、対流
An aviation accident occurs when an airplane was about to land on Narita Airport at 1323 JST on 20 June 2012. No storm was reported, but strong environmental south-westerly winds were presented. In such a situation, convective turbulence organized as roll (roll-shaped convection) may occur in the atmospheric boundary layer. The rolls would align parallel to the environmental wind (south-westerly), and wind speeds may be significantly different between updraft and downdraft regions. The airplane would encounter highly fluctuated winds during landing. A Doppler-Lidar placed at the airport indeed observed patterns that are likely to be associated with the roll-shaped convection.
We conducted a numerical simulation of this case to reproduce detail turbulence structures. A reginal weather prediction model, JMA-NHM (Saito et al., 2006), was used. Numerical domains are centered at Narita Airport. The outer-run was performed with the horizontal resolution of 1 km wherein initial and boundary conditions were given by the Meso-Scale analysis provided by JMA. The inner-run is nested in the outer-run. It horizontal resolution is increased up to 100 m.
The south-westerly prevails on the ocean around the Kanto region due to a synoptic low in the north-east. The result of the outer-run reveals that the south-westerly is locally enhanced on the Tokyo-Bay. The Narita Airport is located only several ten kilometers away from the Tokyo-Bay in the south-west, and is exposed by the enhanced winds.
In the inner-run, the roll convection prevail (Figure) around the airport due to the sensible heat flux from heated lands. Its horizontal structure is comparable to that observed by the Doppler-Lidar. Appearances of local gusts associated with the small scale phenomena have been inferred by some environmental factors. In contrast, our study suggests a recent fine resolution simulation can directly resolve even the turbulence structures and gusts in a real case.
We conducted a numerical simulation of this case to reproduce detail turbulence structures. A reginal weather prediction model, JMA-NHM (Saito et al., 2006), was used. Numerical domains are centered at Narita Airport. The outer-run was performed with the horizontal resolution of 1 km wherein initial and boundary conditions were given by the Meso-Scale analysis provided by JMA. The inner-run is nested in the outer-run. It horizontal resolution is increased up to 100 m.
The south-westerly prevails on the ocean around the Kanto region due to a synoptic low in the north-east. The result of the outer-run reveals that the south-westerly is locally enhanced on the Tokyo-Bay. The Narita Airport is located only several ten kilometers away from the Tokyo-Bay in the south-west, and is exposed by the enhanced winds.
In the inner-run, the roll convection prevail (Figure) around the airport due to the sensible heat flux from heated lands. Its horizontal structure is comparable to that observed by the Doppler-Lidar. Appearances of local gusts associated with the small scale phenomena have been inferred by some environmental factors. In contrast, our study suggests a recent fine resolution simulation can directly resolve even the turbulence structures and gusts in a real case.