Saturday, 13 January 2007
Correlating atmospheric water vapor and hurricane intensity
Research has indicated that there may be a relationship between water vapor and hurricane development; however, traditional methods of measuring water vapor lack the accuracy necessary to make direct correlations. In this study, correlation between hurricane intensity and atmospheric water vapor was investigated. Water vapor data was obtained using the Global Positioning System (GPS). GPS water vapor measurements from areas near the point of landfall of hurricanes that occurred between 2003 and 2005 were obtained and correlated to other hurricane elements such as wind speed and pressure. Findings indicated a direct relationship between the amount of water vapor in the atmosphere and hurricane intensity. Correlation coefficients for atmospheric water vapor and wind speed of tropical cyclones were computed. Coefficients for water vapor and cyclone pressure, and water vapor and atmospheric pressure at the GPS station were computed as well. The absolute values of all coefficients were greater than 0.5. In addition, findings strongly suggested that cyclone intensity decreased without adequate water vapor in areas surrounding the storms. Only one hurricane out of 21 increased in intensity after landfall, and the water vapor measurement from this area was the highest of all readings. The correlation between cyclone intensity and water vapor was not consistent throughout the storm eye. Each hurricane was divided into quadrants, northeast, northwest, southwest, and southeast. GPS stations were then categorized according to the quadrant in which they were located. Coefficients for water vapor and cyclone pressure, as well as water vapor and atmospheric pressure, were computed for each GPS station with respect to this location. Differing water vapor readings, pressure readings, and correlation coefficients reflected the heterogeneity of the cyclone in quadrants. Higher correlations for water vapor measurements taken southeast of the cyclone eye indicate measurements taken from this respective location may be more useful in intensity predictions. Further understanding of water vapor and its role in hurricane development would likely aid in improving tropical cyclone models and forecasts.