On the Relationship between North Atlantic Sea Surface Temperatures and U.S. Hurricane Landfall Risk

Abstract

In the recent literature, considerable attention has been paid to the relationship between climate signals and tropical cyclone activity. Much of the research has focused on Atlantic Ocean basin activity while less attention has been given to landfall frequency and the geographic distribution of risk to life and property. However, recent active seasons like 2004 and 2005 and the resulting damage and economic loss have generated significant interest in the relationship between climate and landfall risk. This study focuses on sea surface temperatures (SST) and examines modulation of landfall activity occurring in anomalously warm-SST seasons. The objective of the study is to evaluate the effect of warmer ocean conditions on U.S. landfall risk. The study is broken into two parts--statistical and physical. The statistical analysis categorizes historical hurricane seasons as either warm or cool and then estimates shifts in landfall frequency under these two climate modes. The analysis is carried out for overall U.S. landfall risk and then for logical subregions along the U.S. coastline. The climatological behavior for warm-SST conditions is developed across the intensity spectrum, from weak tropical storms to major hurricanes, using wind speed as an intensity measure. The analysis suggests that landfall risk is sensitive to SST conditions but that sensitivity varies by region and intensity. The uncertainty associated with these estimates is discussed. The physical analysis is carried out to understand better why landfall risk is not affected uniformly along the U.S. coastline and to reinforce the reasonability of the statistical results. The study involves a detailed examination of the complete life cycle of historical storms. Results indicate that storms making landfall along the East Coast have different genesis and intensification characteristics relative to storms making landfall along the Gulf Coast. As SSTs warm, the genesis pattern shifts, greatly influencing regional landfall risk. Further, hurricane landfalls may react not only to warm-SST conditions, but also to the effect of ocean temperature anomalies on the atmosphere's general circulation. There are implications that complex feedback mechanisms play a role in modulating the probability of landfall, especially from certain parts of the Atlantic basin. Such physical theories provide added confidence in statistical estimates of elevated risk for certain breeds of tropical cyclones.

Mapping the world's tropical cyclone rainfall contribution over land using the TRMM Multi‐satellite Precipitation Analysis

“…In China, about 60% of the population live in coastal areas and this proportion rises to more than 80% for Japan where no one is living more than 120 km from a coast [Hinrichsen, 1999]. While studies suggested that higher sea surface temperatures could result in more destructive TCs [Webster et al, 2005;Emanuel, 2005a;Dailey et al, 2009;Knutson et al, 2010;Vecchi, 2012a, 2013], model projections provided conflicting trends for TC frequency and different long-term predictions with respect to the region considered [Knutson et al, 2010;Mendelsohn et al, 2012]. Once the subject of intense debate within the scientific community [Emanuel, 2005a[Emanuel, , 2005bLandsea, 2005;Pielke, 2005], recent studies have confirmed an upward trend in TC activity for the Atlantic basin while no similar trends were found for the other TC basins throughout the world [Kossin et al, 2007;Vecchi, 2012b, 2013].…”

Moisture transport by Atlantic tropical cyclones onto the North American continent

“…Secondly, additional moisture transport by the TC is favourable to enhanced precipitation but does not guarantee it. Hurricane Hugo in 1989 made landfall in South Carolina causing around one billion dollars of damage by its strong winds, but only produced modest rainfall (Konrad and Perry 2009;Cline 2002). On the other hand, not every heavy rainfall coinciding with TCs can be attributed to TCs (Konrad and Perry 2009;Schumacher and Galarneau 2012).…”

Parameter sensitivity and uncertainty analysis for a storm surge and wave model

“…We select the US North Atlantic coast to evaluate Delft3D model parameter sensitivity because this region is somewhat reliant on numerical simulations for accurate hurricane hazard estimates. Historical hurricane tracks show few landfalling hurricanes of significant strength within the region (Dailey et al, 2009;AOML, 2015) and few coastal surge observations at tidal stations (NOAA, 2015b). A qualitative review of this empirical evidence may imply that hurricane storm surge is not a concern; however, recent research suggests that analysis using only empirical surge and hurricane parameter records is, at best, inconclusive.…”