Structures of Explosively Developing Extratropical Cyclones in Northwestern Pacific by Satellite Data

[ABSTRACT]Horizontal distributions of explosively developing extratropical cyclone formed and developed in Northwestern Pacific Ocean in precipitation, water vapor, cloud liquid water, and surface wind fields are analyzed using the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) on Aqua Satellite dataset in recent 7 winter seasons. Cyclone center-relative compositing mean fields are constructed for four life stages: 1) developing, 2) maximum deepening, 3) minimum center sea level pressure (SLP), and 4) decaying. These stages are distinguished by a value and a kind of differentiation in center SLP using a database of cyclone tracking derived from a reanalysis dataset. The developing processes of the composited cyclone are documented. In developing stage, the・ water vapor pass (WVP) has south-north (high-low) contrast corresponding to the temperature distribution. Corresponding to the cold-dry air mass advections, WVP concentration starts from western part of the cyclone center in the maximum deepening stage. The concentration is distinct along the cold front in the minimum SLP stage. The horizontal distributions at the maximum deepening stage agree with the previous study using global objectively analyzed dataset (GANAL). As the deepening rate is larger, the value and concentration is higher and stronger. Precipitation appears around_ the root of front corresponding to large cloud liquid water, while there is no precipitation near the cyclone center in minimum center SLP and decaying stages regardless of the strength.