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Tropical cyclone formation and motion in the Mozambique Channel
Author(s) -
Matyas Corene J.
Publication year - 2014
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.3985
Subject(s) - madden–julian oscillation , climatology , teleconnection , geopotential height , precipitable water , tropical cyclone , rossby wave , storm , geopotential , geology , tropical cyclone rainfall forecasting , storm track , environmental science , precipitation , extratropical cyclone , atmospheric sciences , geography , el niño southern oscillation , oceanography , cyclone (programming language) , meteorology , convection , field programmable gate array , computer science , computer hardware
Although tropical cyclones ( TCs ) forming in the Mozambique Channel are relatively close to land and have affected vulnerable populations, few studies specifically examine these storms. This study analysed formation frequency and location and storm motion during 1948–2010. A geographic information system was employed to calculate storm trajectory and determine whether or not landfall occurred. Reanalysis data from NCEP / NCAR were examined to identify environmental conditions such as 500 hPa geopotential heights and precipitable water. Nonparametric statistical tests explored relationships between these conditions, TC attributes, and four teleconnections known to influence circulation patterns in the greater Southwest Indian Ocean: the El Niño Southern Oscillation ( ENSO ), Indian Ocean Subtropical Dipole ( IOSD ), Madden‐Julian Oscillation ( MJO ), and Southern Annular Mode ( SAM ). Results show that 94 TCs formed in the channel, with approximately 50% making landfall. Formation frequency varied under different phases of the SAM , IOSD , and MJO . Findings differed when the study period was divided into half, suggesting that inclusion of data prior to 1979 be interpreted cautiously. During the second period, formation tended to occur in the northern (southern) portion of the channel when the IOSD and SAM were negative (positive). The MJO and SAM were associated with differences in precipitable water values, while the MJO and IOSD were associated with track curvature. Geopotential height anomalies at 500 hPa varied under the three phases of ENSO .