DA_Team 3
3. Lower-Level Structure: Dissipation Stage
At the dissipation stage, both ERA5 and JRA-55 show a much broader and less compact circulation than at landfall.
ERA5 still captures a localized low-level wind maximum near the remaining storm center, especially around 850 hPa.
JRA-55 represents the wind field as smoother and more spatially extended,
with strong winds spreading toward northeastern Japan.
This indicates that the storm had lost its compact tropical structure and transitioned
into a broader extratropical-like system.
The vertical cross-section shows that the clear eye–eyewall structure observed near landfall has disappeared by the dissipation stage.
Stronger winds are distributed more broadly in the middle and upper levels rather than being tightly concentrated around the storm center.
ERA5 shows a relatively asymmetric structure, with stronger lower-level winds displaced to one side of the center.
JRA-55 presents a smoother vertical wind distribution, suggesting a more diffused representation of the weakening system.
Positive values indicate stronger ERA5 winds, while negative values indicate stronger JRA-55 winds.
The difference field shows alternating positive and negative regions around the residual storm center, suggesting that the remaining wind maximum is positioned differently in the two datasets.
Negative values near and northeast of the center indicate areas where JRA-55 produces stronger winds than ERA5.
The ERA5 and JRA-55 centers are closer than at landfall, but the wind maximum is still distributed differently between the two datasets.
Overall Interpretation
By the dissipation stage, Hinnamnor no longer maintains a compact typhoon-like lower-level structure.
ERA5 retains a more localized residual circulation, while JRA-55 represents a broader and smoother wind field.
These differences suggest that the two reanalysis datasets interpret the weakening and structural transition of the storm differently after landfall.