Spatiotemporal variability of tropical cyclone genesis density in the Northwest Pacific
Abstract
The small sample size of tropical cyclone (TC) genesis in observations prevents us from fully characterizing its spatiotemporal variations. Here we take advantage of a large ensemble of high-resolution atmospheric simulations to address this issue over the Northwest Pacific during 1973-2010. The variations in TC genesis density are explored separately on interannual and decadal time scales. The interannual variations are dominated by two leading modes. One is characterized by a southeast-northwest dipole pattern and its temporal evolution is closely linked to the eastern Pacific El Niño-Southern Oscillation (ENSO). The other mode features high loadings in the central part of the basin, with out-of-phase changes over the southeastern corner of the basin. This mode is driven by sea surface temperature (SST) variations over the North Indian Ocean and tropical North Atlantic. On decadal time scales, the variations in TC genesis density are primarily controlled by one mode, which exhibits an east-west dipole structure with strong signals confined to the south of 20°N and is tied to the Pacific Decadal Oscillation-like SST anomalies. We further investigate the seasonal evolution of ENSO effect on TC genesis. The results highlight the distinct impacts of different ENSO flavors on TC genesis in the Northwest Pacific during a specific season, and show the strong seasonal dependency of the responses in TC genesis to ENSO.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.A21E..05L