The future impacts of climate change on landfalling tropical cyclones are unclear. Regardless of this uncertainty, flooding by tropical cyclones will increase as a result of accelerated sea-level rise. Under similar rates of rapid sea-level rise during the early Holocene epoch most low-lying sedimentary coastlines were generally much less resilient to storm impacts. Society must learn to live with a rapidly evolving shoreline that is increasingly prone to flooding from tropical cyclones. These impacts can be mitigated partly with adaptive strategies, which include careful stewardship of sediments and reductions in human-induced land subsidence.

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Coastal flooding by tropical cyclones and sea-level rise

Meteorology today : An introduction to weather, Climate, and the environment

The Indian Ocean zonal dipole is a mode of variability in sea surface temperature that seriously affects the climate of many nations around the Indian Ocean rim, as well as the global climate system. It has been the subject of increasing research, and sometimes of scientific debate concerning its existence/nonexistence and dependence/independence on/from the El Nino–Southern Oscillation, since it was first clearly identified in Nature in 1999. Much of the debate occurred because people did not agree on what years are the El Nino or La Nina years, not to mention the newly defined years of the positive or negative dipole. A method that identifies when the positive or negative extrema of the El Nino–Southern Oscillation and Indian Ocean dipole occur is proposed, and this method is used to classify each year from 1876 to 1999. The method is statistical in nature, but has a strong basis on the oceanic physical mechanisms that control the variability of the near-equatorial Indo-Pacific basin. Early in ...

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The Years of El Niño, La Niña, and Interactions with the Tropical Indian Ocean

Clouds within the inner regions of tropical cyclones are unlike those anywhere else in the atmosphere. Convective clouds contributing to cyclogenesis have rotational and deep intense updrafts but tend to have relatively weak downdrafts. Within the eyes of mature tropical cyclones, stratus clouds top a boundary layer capped by subsidence. An outward-sloping eyewall cloud is controlled by adjustment of the vortex toward gradient-wind balance, which is maintained by a slantwise current transporting boundary layer air upward in a nearly conditionally symmetric neutral state. This balance is intermittently upset by buoyancy arising from high-moist-static-energy air entering the base of the eyewall because of the radial influx of low-level air from the far environment, supergradient wind in the eyewall zone, and/or small-scale intense subvortices. The latter contain strong, erect updrafts. Graupel particles and large raindrops produced in the eyewall fall out relatively quickly while ice splinters left...

Clouds in Tropical Cyclones

Reconstructions of past climate are important for providing a historical context for evaluating the nature of 20th century climate change. Here, a number of percentile-based palaeoclimate reconstructions were used to isolate signals of both phases of El Nino-Southern Oscillation (ENSO). A total of 92 (82) El Nino (La Nina) events were reconstructed since A.D. 1525. Significantly, we introduce the most comprehensive La Nina event record compiled to date. This annual record of ENSO events can now be used for independent verification of climate model simulations, reconstructions of ENSO indices and as a chronological control for archaeologists/social scientists interested in human responses to past climate events. Although extreme ENSO events are seen throughout the 478-year ENSO recon- struction, approximately 43% of extreme and 28% of all protracted ENSO events (i.e. both El Nino and La Nina phase) occur in the 20th century. The post-1940 period alone accounts for 30% of extreme ENSO years observed since A.D. 1525. These results suggest that ENSO may operate differently under natural (pre-industrial) and anthropogenic background states. As evidence of stresses on water supply, agriculture and natural ecosystems caused by climate change strengthens, studies into how ENSO will operate under global warming should be a global research priority.

A history of ENSO events since A.D. 1525: implications for future climate change

A significant number of tropical cyclones move into the midlatitudes and transform into extratropical cyclones. This process is generally referred to as extratropical transition (ET). During ET a cyclone frequently produces intense rainfall and strong winds and has increased forward motion, so that such systems pose a serious threat to land and maritime activities. Changes in the structure of a system as it evolves from a tropical to an extratropical cyclone during ET necessitate changes in forecast strategies. In this paper a brief climatology of ET is given and the challenges associated with forecasting extratropical transition are described in terms of the forecast variables (track, intensity, surface winds, precipitation) and their impacts (flooding, bush fires, ocean response). The problems associated with the numerical prediction of ET are discussed. A comprehensive review of the current understanding of the processes involved in ET is presented. Classifications of extratropical transition ...

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The extratropical transition of tropical cyclones : forecast challenges, current understanding, and future directions

El Nino–Southern Oscillation (ENSO) is a natural, coupled atmospheric–oceanic cycle that occurs in the tropical Pacific Ocean on an approximate timescale of 2–7 yr. ENSO events have been shown in previous studies to be related to regional extremes in weather (e.g., hurricane occurrences, frequency and severity of tornadoes, droughts, and floods). The teleconnection of ENSO events to extreme weather events means that the ability to classify an event as El Nino or La Nina is of interest in scientific and other applications. ENSO is most often classified using indices that indicate the warmth and coolness of equatorial tropical Pacific Ocean sea surface temperatures (SSTs). Another commonly used index is based on sea level pressure differences measured across the tropical Pacific Ocean. More recently, other indices have been proposed and have been shown to be effective in describing ENSO events. There is currently no consensus within the scientific community as to which of many indices best captures...

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A Quantitative Evaluation of ENSO Indices

A case study is presented that describes the interaction of Hurricane Bertha (1996) with an extratropical upper-tropospheric trough shortly before the hurricane's landfall in North Carolina. This case study illustrates the evolution of the interaction as seen in water vapor satellite imagery. The similarity of the features in the satellite images to those in gridded analyses of potential vorticity in the upper troposphere suggests that some types of trough interactions may be identifiable from satellite imagery.

/pdf/the-evolution-of-a-hurricane-trough-interaction-from-a-43srh9e8tp.pdf

The evolution of a hurricane-trough interaction from a satellite perspective

El Nino-Southern Oscillation (ENSO) is a natural, coupled atmospheric-oceanic cycle that occurs in the tropical Pacific Ocean on an approximate timescale of 2-7 yr. ENSO events have been shown in previous studies to be related to regional extremes in weather (e.g., hurricane occurrences, frequency and severity of tornadoes, droughts, and floods). The teleconnection of ENSO events to extreme weather events means that the ability to classify an event as El Nino or La Nina is of interest in scientific and other applications. ENSO is most often classified using indices that indicate the warmth and coolness of equatorial tropical Pacific Ocean sea surface temperatures (SSTs). Another commonly used index is based on sea level pressure differences measured across the tropical Pacific Ocean. More recently, other indices have been proposed and have been shown to be effective in describing ENSO events. There is currently no consensus within the scientific community as to which of many indices best captures ENSO phases. The goal of this study is to compare several commonly used ENSO indices and to determine whether or not one index is superior in defining ENSO events; or alter- natively, to determine which indices are best for various applications. The response and sensitivity of the SST-based indices and pressure-based indices are compared. The Nino-4 index has a relatively weak response to El Nino; the Nino-1 12 index has a relatively strong response to La Nina. Analysis of the sensitivity of the indices relative to one another suggests that the choice of index to use in ENSO studies is dependent upon the phase of ENSO that is to be studied. The Japan Meteorological Agency (JMA) index is found to be more sensitive to La Nina events than all other indices. The Southern Oscillation, Nino-3.4, and Nino-4 indices are almost equally sensitive to El Nino events and are more sensitive than the JMA, Nino-1 12, and Nino-3 indices.

https://journals.ametsoc.org/doi/pdf/10.1175/1520-0442(2003)16%3C1249%3AAQEOEI%3E2.0.CO%3B2

Deborah E. Hanley

Papers

The extratropical transition of tropical cyclones : forecast challenges, current understanding, and future directions

A Quantitative Evaluation of ENSO Indices

The evolution of a hurricane-trough interaction from a satellite perspective

NOTES AND CORRESPONDENCE A Quantitative Evaluation of ENSO Indices