Monitoring and prediction of hurricane tracks using GPS tropospheric products

We have reconstructed integrated water vapor (IWV) using the zenith wet delays to track the properties of hurricanes and explore their spatial and temporal distributions estimated from 922 GPS stations. Our results show that a surge in GPS-derived IWV occurred at least six hours prior to the landfall of two major hurricanes (Harvey and Irma) that struck the Gulf and East Coasts of the USA in 2017. We observed enhanced IWV, in particular, for the two hurricanes landfall locations. The observed variations exhibit a correlation with the precipitation value constructed from GPM/IMERG satellite mission coinciding with hurricane storm front passage. We used GPS-IWV data as inputs for spaghetti line plots for our path predictions, helping us predict the paths of Hurricanes Harvey and Irma. Hence, a directly estimable zenith wet delay sourced from GPS that has not been previously reported can serve as an additional resource for improving the monitoring of hurricane paths.

Perceptions of Hurricane-Track Forecasts in the United States

Hurricanes Isaac (2012), Harvey (2017), and Irma (2017) were storms with different geophysical characteristics and track forecast consistencies. Despite the differences, common themes emerged from the perception of track forecasts from evacuees for each storm. Surveys with a mixture of closed and open-ended responses were conducted during the evacuations of each storm while the storm characteristics and decision-making were fresh in the minds of evacuees. Track perception accuracy for each evacuee was quantified by taking the difference between three metrics: perceived track and official track (PT − OT), perceived track and forecast track (PT − FT), and home location and perceived track (HL − PT). Evacuees from Hurricanes Isaac and Harvey displayed a tendency to perceive hurricane tracks as being closer to their home locations than what was forecast to occur and what actually occurred. The large sample collected for Hurricane Irma provided a chance to statistically verify some of the hypotheses generated from Isaac and Harvey. Results from Hurricane Irma confirmed that evacuees expected a storm to be closer to their home locations after controlling for regional influences. Furthermore, participants with greater previous hurricane experience perceived a track as being closer to their home locations, and participants residing in zip codes corresponding with nonmandatory evacuation zones also perceived tracks as being closer to their home locations. These findings suggest that most evacuees from hurricanes in the United States appear to perceive storms as being closer to their home locations than they are and overestimate wind speeds at their homes, thus overestimating the true danger from landfalling hurricanes in many storms.

The Economic Impact of Hurricanes in History: Evidence from Sugar Exports in the Caribbean from 1700 to 1960

This study estimates the economic impact of hurricane strikes in the Caribbean from 1700 to 1960. More precisely, historical accounts of hurricane strikes and actual historical hurricane tracks, in conjunction with sugar export data taken from the colonial blue books and other historical sources, were used to create a cross-colony/country and time dataset that allows for the first time the ability to evaluate the susceptibility of local sugar production to hurricanes. The regression results show that these events had generally large statistically and economically significant impacts.

Climate Modulation of North Atlantic Hurricane Tracks

The variability of North Atlantic tropical storm and hurricane tracks, and its relationship to climate variability, is explored. Tracks from the North Atlantic hurricane database for the period 1950–2007 are objectively separated into four groups using a cluster technique that has been previously applied to tropical cyclones in other ocean basins. The four clusters form zonal and meridional separations of the tracks. The meridional separation largely captures the separation between tropical and more baroclinic systems, while the zonal separation segregates Gulf of Mexico and Cape Verde storms. General climatologies of the seasonality, intensity, landfall probability, and historical destructiveness of each cluster are documented, and relationships between cluster membership and climate variability across a broad spectrum of time scales are identified. Composites, with respect to cluster membership, of sea surface temperature and other environmental fields show that regional and remote modes of climate variability modulate the cluster members in substantially differing ways and further demonstrate that factors such as El Niño–Southern Oscillation (ENSO), Atlantic meridional mode (AMM), North Atlantic Oscillation (NAO), and Madden–Julian oscillation (MJO) have varying intrabasin influences on North Atlantic tropical storms and hurricanes. Relationships with African easterly waves are also considered. The AMM and ENSO are found to most strongly modulate the deep tropical systems, while the MJO most strongly modulates Gulf of Mexico storms and the NAO most strongly modulates storms that form to the north and west of their Cape Verde counterparts and closer to the NAO centers of action. Different clusters also contribute differently to the observed trends in North Atlantic storm frequency and may be related to intrabasin differences in sea surface temperature trends. Frequency trends are dominated by the deep tropical systems, which account for most of the major hurricanes and overall power dissipation. Contrarily, there are no discernable trends in the frequency of Gulf of Mexico storms, which account for the majority of landfalling storms. When the proportion that each cluster contributes to overall frequency is considered, there are clear shifts between the deep tropical systems and the more baroclinic systems. A shift toward proportionally more deep tropical systems began in the early to mid-1980s more than 10 years before the 1995 North Atlantic hurricane season, which is generally used to mark the beginning of the present period of heightened activity.