Relationship Between Sea Surface Temperature and Maximum Intensity of TropicalCyclones in the Eastern North Pacific Ocean

摘要

An empirical relationship between climatological sea surface temperature (SST)and maximum intensity of Eastern North Pacific tropical cyclones is developed from a 31-year sample (1963-1993). This relationship is compared with the relationship for Atlantic tropical cyclones developed in a similar study by DeMaria and Kaplan and with the theoretical results of Emanuel. Overall, Eastern North Pacific storms do not come as close to their maximum potential intensity (MPI) as do Atlantic storms. At the time of their maximum intensity only 11% of Eastern North Pacific storms reach 8O% or more of their MPI compared with 19% in the Atlantic. Poleward recurvature of Atlantic storms over cooler waters appears to be a major factor in the difference between the two empirical relationships. Storms that mature west of 110 deg. W tend to reach a considerably higher fraction of their MPI than storms that reach their maximum intensity east of 110 deg. W. Assuming the tropopause temperature is a function of SST, the theoretical results are in general agreement with the observations over SSTs of 24 to 28 deg. C. During El Nino years, Eastern North Pacific storms reach their maturity at positions farther south and farther west than in non-El Nino years. Storms also tend to obtain a higher portion of their MPI and reach higher maximum intensities when the QBO is in its westerly phase.