Article
What Controls Early or Late Onset of Tropical North Atlantic Hurricane Season?
Journal of Meteorological Research
Zuo Heng; Tim Li; Liu Jia; Peng Melinda
Abstract
The occurrence of ?rst hurricane in early summer signi?es the onset of an active Atlantic hurricane season. The interannual variation of this hurricane onset date is examined for the period 1979–2013. It is found that the onset date has a marked interannual variation. The standard deviation of the interannual variation of the onset day is 17.5 days, with the climatological mean onset happening on July 23. A diagnosis of tropical cyclone (TC) genesis potential index (GPI) indicates that the major di?erence between an early and a late onset group lies in the maximum potential intensity (MPI). A further diagnosis of the MPI shows that it is primarily controlled by the local SST anomaly (SSTA). Besides the SSTA, vertical shear and mid-tropospheric relative humidity anomalies also contribute signi?cantly to the GPI di?erence between the early and late onset groups. It is found that the anomalous warm (cold) SST over the tropical Atlantic, while uncorrelated with the Nin?o3 index, persists from the preceding winter to concurrent summer in the early (late) onset group. The net surface heat ?ux anomaly always tends to damp the SSTA, which suggests that ocean dynamics may play a role in maintaining the SSTA in the tropical Atlantic. The SSTA pattern with a maximum center in northeastern tropical Atlantic appears responsible for generating the observed wind and moisture anomalies over the main TC development region. A further study is needed to understand the initiation mechanism of the SSTA in the Atlantic.
左恒, 李天明, 刘佳, et al. What Controls Early or Late Onset of Tropical North Atlantic Hurricane Season?[J]. 气象学报英文版, 2016, 30(3):298-311.
