Tropical cyclone formation and motion in the Mozambique Channel

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 Nino 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.

[1]  Mathieu Rouault,et al.  Rainfall Variability and Changes in Southern Africa during the 20th Century in the Global Warming Context , 2003 .

[2]  Martin Widmann,et al.  Atmospheric science: Early peak in Antarctic oscillation index , 2004, Nature.

[3]  F. Vitart,et al.  Seasonal Forecasting of Tropical Cyclone Landfall over Mozambique , 2003 .

[4]  A. Barnston,et al.  Clustering of eastern North Pacific tropical cyclone tracks: ENSO and MJO effects , 2008 .

[5]  Julie A. Silva.  A Multilevel Analysis of Agricultural Trade and Socioeconomic Inequality in Rural Mozambique , 2008 .

[6]  M. Sinclair.  Extratropical Transition of Southwest Pacific Tropical Cyclones. Part I: Climatology and Mean Structure Changes , 2002 .

[7]  David A Jones,et al.  On tropical cyclone activity in the Southern Hemisphere: Trends and the ENSO connection , 2008 .

[8]  P. Terray,et al.  Indian Ocean Sea Surface Temperature and El Niño–Southern Oscillation: A New Perspective , 2005 .

[9]  R. Washington,et al.  Extreme wet years over southern Africa: Role of Indian Ocean sea surface temperatures , 2006 .

[10]  Jong‐Jin Baik,et al.  The Environmental Influence on Tropical Cyclone Precipitation , 1994 .

[11]  H. Kadomura.  CLIMATE ANOMALIES AND EXTREME EVENTS IN AFRICA IN 2003, INCLUDING HEAVY RAINS AND FLOODS THAT OCCURRED DURING NORTHERN HEMISPHERE SUMMER , 2005 .

[12]  R. Boyles,et al.  Characteristics of Landfalling Tropical Cyclones in North Carolina , 2010 .

[13]  D. Gong,et al.  Definition of Antarctic Oscillation index , 1999 .

[14]  Fuzhong Weng,et al.  An eight-year (1987-1994) time series of rainfall, clouds, water vapor, snow cover, and sea ice derived from SSM/I measurements , 1996 .

[15]  Relationships between the Antarctic Oscillation, the Madden-Julian Oscillation, and ENSO, and Consequences for Rainfall Analysis , 2010 .

[16]  P. R. Julian,et al.  Observations of the 40-50-day tropical oscillation - a review , 1994 .

[17]  Kerry Emanuel,et al.  An Air-Sea Interaction Theory for Tropical Cyclones. Part I: Steady-State Maintenance , 1986 .

[18]  Kevin E. Trenberth,et al.  Evaluation of the atmospheric moisture and hydrological cycle in the NCEP/NCAR reanalyses , 1998 .

[19]  Kevin D. Ash,et al.  The influences of ENSO and the subtropical Indian Ocean Dipole on tropical cyclone trajectories in the southwestern Indian Ocean , 2012 .

[20]  R. Reynolds,et al.  The NCEP/NCAR 40-Year Reanalysis Project , 1996, Renewable Energy.

[21]  W. M. Gray,et al.  GLOBAL VIEW OF THE ORIGIN OF TROPICAL DISTURBANCES AND STORMS , 1968 .

[22]  T. Yamagata,et al.  Indian Ocean subtropical dipole simulated using a coupled general circulation model , 2004 .

[23]  C. Reason.  Tropical cyclone Dera, the unusual 2000/01 tropical cyclone season in the South West Indian Ocean and associated rainfall anomalies over Southern Africa , 2007 .

[24]  Y. Takayabu,et al.  Equatorial Circumnavigation of Moisture Signal Associated with the Madden-Julian Oscillation (MJO) during Boreal Winter , 2003 .

[25]  Julie A. Silva,et al.  Extreme weather and economic well-being in rural Mozambique , 2013, Natural Hazards.

[26]  H. Byun,et al.  Possible relationship between western North Pacific tropical cyclone activity and Arctic Oscillation , 2010 .

[27]  H. Ramsay,et al.  Cluster analysis of tropical cyclone tracks in the Southern Hemisphere , 2012, Climate Dynamics.

[28]  W. Briggs.  Statistical Methods in the Atmospheric Sciences , 2007 .

[29]  Herbert Riehl,et al.  On the Dynamics and Energy Transformations in Steady‐State Hurricanes , 1960 .

[30]  E. Möbius,et al.  Charge states of energetic (≈0.5 MeV/n) ions in corotating interaction regions at 1 AU and implications on source populations , 2002 .

[31]  Swadhin K. Behera,et al.  Subtropical SST dipole events in the southern Indian Ocean , 2001 .

[32]  C. Jones,et al.  Opposite Phases of the Antarctic Oscillation and Relationships with Intraseasonal to Interannual Activity in the Tropics during the Austral Summer , 2005 .

[33]  Miloud Bessafi,et al.  Modulation of South Indian Ocean Tropical Cyclones by the Madden–Julian Oscillation and Convectively Coupled Equatorial Waves , 2006 .

[34]  L. A. Du Plessis,et al.  A review of effective flood forecasting, warning and response system for application in South Africa , 2002 .

[35]  M. Wheeler,et al.  An All-Season Real-Time Multivariate MJO Index: Development of an Index for Monitoring and Prediction , 2004 .

[36]  D. Levinson,et al.  A Technique for Combining Global Tropical Cyclone Best Track Data , 2010 .

[37]  L. Leslie,et al.  Links between Tropical Cyclone Activity and Madden-Julian Oscillation Phase in the North Atlantic and Northeast Pacific Basins , 2008 .

[38]  P. Chu,et al.  Large-Scale Circulation Features Associated with Decadal Variations of Tropical Cyclone Activity over the Central North Pacific , 2002 .

[39]  W. Landman,et al.  Transient convective waves in the tropical SW Indian Ocean , 1991 .

[40]  C. J. Neumann,et al.  The International Best Track Archive for Climate Stewardship (IBTrACS): unifying tropical cyclone data. , 2010 .

[41]  A preliminary study of climatological associations and characteristics of tropical cyclones in the SW Indian Ocean , 1993 .

[42]  H. B. Mann,et al.  On a Test of Whether one of Two Random Variables is Stochastically Larger than the Other , 1947 .

[43]  C. J. Neumann,et al.  Statistical Prediction of Tropical Cyclone Motion over the Southwest Indian Ocean , 1976 .

[44]  Suzana J. Camargo,et al.  Revisiting the Influence of the Quasi-Biennial Oscillation on Tropical Cyclone Activity , 2010 .

[45]  Matthew C. Wheeler,et al.  Statistical Prediction of Weekly Tropical Cyclone Activity in the Southern Hemisphere , 2008 .

[46]  C. Reason,et al.  Dry spell frequencies and their variability over southern Africa , 2004 .

[47]  R. Higgins,et al.  Characteristics of Landfalling Tropical Cyclones in the United States and Mexico: Climatology and Interannual Variability , 2005 .

[48]  Jianping Li,et al.  The relationship between the summer precipitation in the Yangtze River valley and the boreal spring Southern Hemisphere annular mode , 2003 .

[49]  C. Reason,et al.  On the peculiar storm track of TC Favio during the 2006–2007 Southwest Indian Ocean tropical cyclone season and relationships to ENSO , 2008 .

[50]  Chang‐Hoi Ho,et al.  Variation of tropical cyclone activity in the South Indian Ocean: El Niño–Southern Oscillation and Madden‐Julian Oscillation effects , 2006 .

[51]  C. Reason,et al.  Tropical Cyclone Eline and its unusual penetration and impacts over the southern African mainland , 2004 .

[52]  C. Reason,et al.  The sensitivity of the Seychelles–Chagos thermocline ridge to large-scale wind anomalies , 2009 .

[53]  G. Schmidt,et al.  Southern Hemisphere climate response to ozone changes and greenhouse gas increases , 2004 .

[54]  M. Rouault,et al.  Climatology and Landfall of Tropical Cyclones in the South- West Indian Ocean , 2010 .

[55]  M. Jury,et al.  Climatic Determinants and Statistical Prediction of Tropical Cyclone Days in the Southwest Indian Ocean , 1999 .

[56]  Graeme L. Stephens,et al.  On the relationship between water vapor over the oceans and sea surface temperature , 1990 .

[57]  I. Smith,et al.  Association between Australian rainfall and the Southern Annular Mode , 2007 .

[58]  Ick Hoi Kim,et al.  Sinuosity of tropical cyclone tracks in the South West Indian Ocean: Spatio-temporal patterns and relationships with fundamental storm attributes , 2013 .

[59]  W. Kruskal,et al.  Use of Ranks in One-Criterion Variance Analysis , 1952 .

[60]  M. Jury,et al.  A study of climate and weather variability over the tropical southwest Indian Ocean , 1991 .

[61]  G. Bigg,et al.  Bimodal Distribution of Tropical Cyclogenesis in the Caribbean: Characteristics and Environmental Factors. , 2002 .

[62]  C. Reason,et al.  Ocean Model Diagnosis of Interannual Coevolving SST Variability in the South Indian and South Atlantic Oceans , 2005 .

[63]  W. Landman,et al.  Tropical systems from the southwest Indian Ocean making landfall over the Limpopo River Basin, southern Africa: a historical perspective , 2012 .

[64]  Nicolas Fauchereau,et al.  ENSO and Indian Ocean sea surface temperatures and their relationships with tropical temperate troughs over Mozambique and the Southwest Indian Ocean , 2011 .

[65]  Bin Wang,et al.  Development Characteristics and Dynamic Structure of Tropical Intraseasonal Convection Anomalies , 1990 .

[66]  R. Washington,et al.  Circulation anomalies associated with tropical-temperate troughs in southern Africa and the south west Indian Ocean , 1999 .

[67]  A. Sobel,et al.  Diagnosis of the MJO Modulation of Tropical Cyclogenesis Using an Empirical Index , 2009 .

[68]  M. Jury,et al.  Tropical cyclone composite structure and impacts over eastern Madagascar during January–March 1994 , 1998 .

[69]  M. Jury,et al.  Tropical cyclones in the SW Indian Ocean. Part 1: inter-annual variability and statistical prediction , 2010 .

[70]  N. Fučkar,et al.  Southern Hemisphere Origins of the 1976 Climate Shift , 2002 .

[71]  J. H. Zar,et al.  Significance Testing of the Spearman Rank Correlation Coefficient , 1972 .

[72]  Huijun Wang,et al.  Interannual Variability of Mascarene High and Australian High and Their Influences on East Asian Summer Monsoon , 2004 .

[73]  C. Reason,et al.  Sensitivity of the southern African circulation to dipole sea‐surface temperature patterns in the south Indian Ocean , 2002 .

[74]  W. M. Gray,et al.  An Observational Analysis of Tropical Cyclone Recurvature , 1993 .