RELATIONSHIPS BETWEEN BASIN-WIDE AND LANDFALLING ATLANTIC TROPICAL CYCLONES: COMPARING LONG-TERM SIMULATIONS WITH PALEOEVIDENCE (Invited Presentation)

Substantial uncertainties exist regarding the long-term relationships between various measures of Atlantic Tropical Cyclone (TC) activity, e.g. annual total named storm counts vs. major landfalling U.S. hurricanes. Evaluating relationships from historical observations is perilous, as the records are short, spanning little more than a century, and observational biases potentially become quite substantial in earlier decades. Comparisons are further hampered by the fact that these biases may have differential impacts on different quantities. Here, we instead examine the relationships between various measures of Atlantic TC activity using the idealized framework provided by a climate model simulation subject to estimated natural and anthropogenic radiative forcing over the past millennium (AD 850-1999). Following the downscaling approach of Emanuel et al [K.A. Emanuel et al, Hurricanes and Global Warming, Bull. Am. Met. Soc., DOI:10.1175/BAMS-89-3-347, 2008] we use the large-scale fields of the climate model simulation to force a model of tropical cyclone genesis, tracking, and intensification. This process yields synthetic long-term basin-wide seasonal TC histories with realistic statistical attributes. Using the simulated TC histories, we examine relationships between basin-wide TC activity, landfalling TCs, hurricanes, landfalling hurricanes, and major U.S. landfalling hurricanes on timescales ranging from the interannual through centennial. We also use these synthetic TC histories to assess the limitations of inferences that can be drawn from networks of geological records of past landfalling hurricane activity.