Search for: All records

Abstract Pielke deprecates both the ICAT database, which he once recommended, and U.S. tropical cyclone (TC) damage estimates from the National Centers for Environmental Information (NCEI). We do not share these views. Willoughby et al. (hereafter WL24) is based upon ICAT damage for 1900–2017, both then-year and normalized for inflation, population, and individual wealth, extended to 2022 with National Hurricane Center (NHC) official figures from NCEI. Pielke represents the data of Weinkle et al. (hereafter WK18) as a superior source. We find troubling anomalies in the WK18 data. The issue is that WK18 find that normalized TC damage is constant, but WL24 find that it is increasing. Here, we replicate the WL24 analysis with WK18 data and find a statistically significant growth of then-year damage relative to the U.S. economy, a statistically significant increase in the occurrence of the most damaging TCs, and a 0.6% per year increase in TC normalized damage. The last of these is not statistically significant because of the large variance due to the modulation of TC impacts by the Atlantic multidecadal oscillation. Thus, the increase in U.S. TC damage is sufficiently robust to survive the shortcomings of both datasets. 

Abstract A series of papers published since 1998 assert that U.S. tropical cyclone (TC) damage, when “normalized” for individual wealth, population, and inflation, exhibits no increase attributable to anthropogenic global warming (AGW). This result is here questioned for three reasons: 1) The then-year (no demographic or economic adjustments) U.S. TC damage increases 2.5% yr⁻¹faster than U.S. then-year gross domestic product. This result, which is substantially due to the faster growth of assets in hurricane-prone states, shows that TC impacts on the total U.S. economy double every generation. 2) Fitting of an exponential curve to normalized damage binned by 5-yr “pentads” yields a growth rate of 1.06% yr⁻¹since 1900, although causes besides AGW may contribute. 3) During the twenty-first century, when the Atlantic multidecadal oscillation (AMO) was in its warm phase, the most damaging U.S. TCs struck at twice the rate of the warm AMO of the twentieth century and 4 times the rate of the entire twentieth century, both warm and cool AMO phases. A key unanswered question is as follows: What will happen when (and if) the AMO returns to its cool phase later in this century? Significance StatementU.S. hurricane damage, normalized for changes in inflation, population, and wealth, increases by approximately 1% yr⁻¹. For 1900–2022, 1% yr⁻¹is equivalent to a factor of >3 increase, substantially but not entirely, attributable to climate change. The incidence of the most damaging tropical cyclones (TCs) approximately doubled in the twenty-first century compared with climatologically analogous periods of the twentieth century. These results contradict the previously published work that introduced normalization and found zero trend in normalized damage but are consistent with physical reasoning and modeling studies. 

Abstract Vortex Rossby waves (VRWs) affect tropical cyclones’ (TCs’) motion, structure, and intensity. They propagate within annular waveguides defined by a passband between Ω_1D, the Doppler-shifted frequency of a one-dimensional VRW, and zero. Wavenumber-1 VRWs cause TC motion directly and have wider waveguides than wavenumbers ≥ 2. VRWs forced with fixed rotation frequency propagate away from the forcing. Initially outward-propagating waves are Doppler shifted to zero at a critical radius, where they are absorbed. Initially inward-propagating waves are Doppler shifted to Ω_1D, reflect from a turning point, propagate outward, and are ultimately absorbed at the critical radius. Between the forcing and the turning radii, the VRWs have standing-wave structure; outward from the forcing they are trailing spirals. They carry angular momentum fluxes that act to accelerate the mean flow at the forcing radius and decelerate it at the critical radius. Mean-flow vorticity monopoles are inconsistent with Stokes’s theorem on a spherical Earth, because a contour enclosing the monopole’s antipode would have nonzero circulation but would enclose zero vorticity. The Rossby waveguide paradigm also fits synoptic-scale Rossby waves in a meridionally sheared zonal flow. These waves propagate within a waveguide confined between a poleward turning latitude and an equatorward critical latitude. Forced waves are comma-shaped gyres that resemble observed frontal cyclones, with trailing filaments equatorward of the forcing latitude and standing waves poleward. Even neutral forced Rossby waves converge westerly momentum at the latitude of forcing.