Impact Of Cyclones Research Articles

Research of synoptic processes in the south-east of the Russian plain during different climatic periods

This article examines the annual and seasonal (winter and summer) changes in the frequency of occurrence of the main types of synoptic processes in the Lower Volga region in two natural climatic periods of the state of the earth climatic system - the stabilization period and the second wave of global warming. The frequency of occurrence of some types of synoptic processes revealed both climatic and seasonal differences. In the second wave of global warming, in comparison with the stabilization period, the frequency of cyclone impact on the Lower Volga region developed on the Arctic front and the number of Arctic anticyclones increase, and the frequency of polar-front cyclones and cases of the impact of the western periphery of the winter Asian anticyclone decreases. Seasonal differences in the frequency of occurrence were revealed in the Arctic anticyclones. During the second wave of global warming, these anticyclones penetrate into the Lower Volga region in summer more often than in winter. It is concluded that the contribution of the transformation factor to the observed warming increases and the role of summer seasons in the observed climatic changes increases, which is not typical for processes in the earth climatic system. It is indicated that obtained result is of great climatological significance and will serve the further development of the physical theory of climate.

Cyclone Impacts on Coral Reef Communities in Southwest Madagascar

Tropical cyclones can cause severe destruction of coral reefs with ecological consequences for reef fish communities. Ocean warming is predicted to shorten the return interval for strong tropical cyclones. Understanding the consequences of cyclone impacts on coral reefs is critical to inform local-scale management to support reef resilience and the livelihood security of small-scale fishing communities. Here, we present the first analysis of a tropical cyclone disturbance on coral reefs in Madagascar. We investigate the impact of Cyclone Haruna (category 3 Saffir-Simpson scale) in February 2013 on coral communities, both adults and recruits, and explore the relationship between the severity of cyclone impact with cyclone parameters (wind speed, duration of storm impact and distance from cyclone track) and environmental variables (reef type and reef depth). We use survey data collected as part of a long-term citizen science monitoring programme at 21 coral reef sites between 2012 and 2015 in the Velondriake Locally Managed Marine Area along Madagascar’s southwest coast. Coral cover declined at 19 sites, however damage was spatially heterogeneous ranging from a decrease in coral cover of 1.4% to 45.8%. We found the severity of cyclone damage related to: distance from the cyclone track, duration of cyclone impact and reef depth. The taxonomic and morphological composition of coral communities was significantly different after the cyclone. Notably, there was a decrease in the dominance of branching morphologies, and an increase in the relative abundance of encrusting and massive morphologies. Two years after Cyclone Haruna, mean coral cover had increased and the density of coral recruits increased to above pre-cyclone levels indicating the potential recovery of coral populations. However, recovery to pre-disturbance community composition will likely be hindered by the increasing occurrence of acute and chronic disturbance events.

Influence of Tropical Cyclones on Outdoor Wind Environment in High-Rise Residential Areas in Zhejiang Province, China

Tropical cyclones can cause tremendous harm to coastal areas. This research aims to explore the influence of tropical cyclones on outdoor wind environments in high-rise residential areas in the southeast coastal provinces of China, using Zhejiang Province as an example. It investigated four cities located in Zhejiang Province, including Taizhou and Wenzhou representing coastal cities, and Huzhou and Jiaxing representing inland cities, and collected data from 209 high-rise residential areas. Of these 209 samples, 131 high-rise residential areas with three typical spatial layouts (i.e., rows-style, free-style, and courtyard-style) have been selected for further studies. Numerical simulation was conducted to analyze the outdoor wind environment of these three types of high-rise residential areas, where the height of buildings was set as 26 floors (75 m), during tropical cyclones. Based on a comparison of the wind velocity at the horizontal planes of 1.5 m high and 10 m high, it was found that the spatial layouts of high-rise residential areas could mitigate the negative impact of tropical cyclones on the outdoor wind environment. Specifically, in the coastal cities, the courtyard-style layout led to a relatively small proportion of high wind speed areas (e.g., wind velocity above 14.4 m/s) in the high-rise residential areas; and in the inland cities, the free-style layout led to a relatively small proportion of high wind speed area in the high-rise residential area. In turn, to better cope with the tropical cyclones, it was suggested that the courtyard-style layout should be recommended for high-rise residential areas located in the coastal cities and the free-style layout should be recommended for high-rise residential areas located in the inland cities in coastal provinces.

The impact of tropical cyclones on potential offshore wind farms

The climate crisis has led to an increased interest in renewable energy, and in wind energy in particular. Wind farms with the largest generating potential are generally located offshore. In this study we consider the case of Mexico, a sub-tropical country in North-America. Due to Mexico's location, offshore wind farms (OWF) would be at risk of damage from strong winds associated with tropical cyclones (TCs) in both the Pacific and the Gulf of Mexico basins. Thus, here we ask whether there are any regions in Mexico combining a high generating potential and a low risk from tropical cyclones. To answer this question, the ERA5 reanalysis has been used to identify two sites on the Pacific coast and two sites in the Gulf of Mexico with high wind power potential. Then, using the ERA5 reanalysis and TC best-track observational data, the potential effects of four major hurricanes and the climatological hazard posed by TC-related damaging winds on OWFs at those sites have been investigated. The return period for TCs with near-surface winds exceeding 50m s−1, a threshold associated with increased structural damage likelihood, has been estimated at as low as 8 years for the Gulf of Mexico and above 64 years for Pacific coast. Therefore, in terms of the magnitude of the TC-related hazard, the Pacific coast sites are found to be preferred as locations for the development of OWFs. These results are relevant for any planning of offshore wind energy in Mexico, and the methodology applicable to any other sub-tropical region in which the risk of tropical cyclones is present.

Income and extratropical cyclones in New Zealand

Aotearoa New Zealand is highly vulnerable to extratropical cyclones because of its unique location in the midlatitude south pacific region. This study empirically investigates the impact of the extratropical cyclones on individual income, combining the data from Statistics New Zealand's Integrated Data Infrastructure (IDI) and the weather-related insurance claims data from the Earthquake Commission. Our sample covers the administrative longitudinal panel data of all the IRD registered individual taxpayers between 2010 and 2019. We estimate a set of panel regressions with individual and time-fixed effects to assess the impact of extratropical cyclones on the affected individual's annual income. We find that income from salaries and wages is negatively affected by the cyclones across various specifications. Extratropical cyclones also negatively affect the total individual income from wages and salaries, benefit and compensation, and sole tradership. However, we have limited success in identifying individual characteristics influencing the affected people's income level in our study.

Previous Shoreline Dynamics Determine Future Susceptibility to Cyclone Impact in the Sundarban Mangrove Forest

Extreme weather events are a cause of mangrove forest loss and degradation globally. Almost half of the world’s mangroves are found in the tropical cyclone belt, and forests often experience disturbance in structure, functioning and ecosystem service provision. Understanding the factors that increase the vulnerability of mangroves to such disturbances is a challenge. Using a novel remote sensing analysis combining water class change with vegetation classification, we showed that mangrove loss across multiple cyclone events is influenced by previous erosion history, suggesting that the prior state of the coastline affects susceptibility to future disturbance events. During Cyclone Amphan in May 2020, more than 1,200 km2 of mangroves were damaged and 40.6 km2 of shoreline was lost. Cyclone Amphan caused the most damage out of three recent cyclones, with the most mangrove loss (18.8%) experienced along shorelines that were eroding over the past 35 years. This can be explained by the long-term effect of erosion on the overall intertidal morphology of the shoreline. Landscape-scale mangrove management, particularly of sediment budgets is essential to switch previously eroding mangroves to a state where they can withstand cumulative storm impacts.

A cyclone-centered perspective on the drivers of asymmetric patterns in the atmosphere and sea ice during Arctic cyclones

AbstractArctic cyclones are an extremely common, year-round phenomenon, with substantial influence on sea ice. However, few studies address the heterogeneity in the spatial patterns in the atmosphere and sea ice during Arctic cyclones. We investigate these spatial patterns by compositing on cyclones from 1985-2016 using a novel, cyclone-centered approach that reveals conditions as functions of bearing and distance from cyclone centers. An axisymmetric, cold core model for the structure of Arctic cyclones has previously been proposed, however, we show that the structure of Arctic cyclones is comparable to those in the mid-latitudes, with cyclonic surface winds, a warm, moist sector to the east of cyclones and a cold, dry sector to the west. There is no consensus on the impact of Arctic cyclones on sea ice, as some studies have shown that Arctic cyclones lead to sea ice growth and others to sea ice loss. Instead, we find that sea ice decreases to the east of Arctic cyclones and increases to the west, with the greatest changes occurring in the marginal ice zone. Using a sea ice model forced with prescribed atmospheric reanalysis, we reveal the relative importance of the dynamic and thermodynamic forcing of Arctic cyclones on sea ice. The dynamic and thermodynamic responses of sea ice concentration to cyclones are comparable in magnitude, however dynamic processes dominate the response of sea ice thickness and are the primary driver of the east-west difference in the sea ice response to cyclones.

Tropical Cyclone Impact and Forest Resilience in the Southwestern Pacific

Tropical cyclones (TCs) can have profound effects on the dynamics of forest vegetation that need to be better understood. Here, we analysed changes in forest vegetation induced by TCs using the normalized difference vegetation index (NDVI). We used an accurate historical database of TC tracks and intensities, together with the Willoughby cyclone model to reconstruct the 2D surface wind speed structure of TCs and analyse how TCs affect forest vegetation. We used segmented linear models to identify significant breakpoints in the relationship between the reconstructed maximum sustained wind speed (Wmax) and the observed changes in NDVI. We tested the hypothesis that the rate of change in damage caused by TCs to forest and recovery time would increase according to Wmax thresholds as defined in the widely used Saffir–Simpson hurricane wind scale (SSHWS). We showed that the most significant breakpoint was located at 50 m/s. This breakpoint corresponds to the transition between categories 2 and 3 TCs in the SSHWS. Below this breakpoint, damages caused to forest vegetation and the time needed to recover from these damages were negligable. We found a second breakpoint, with a sharp increase in damages for winds >75 m/s. This suggested that extremely intense tropical cyclones, which might be more frequent in the future, can cause extreme damages to forest vegetation. Nevertheless, we found high variation in the observed damages and time needed to recover for a given Wmax. Further studies are needed to integrate other factors that might affect the exposure and resistance to TCs as well as forests’ capacity to recover from these disturbances.

Biogeochemical Dynamics in Adjacent Mesoscale Eddies of Opposite Polarity

AbstractWe examined the biogeochemical impact of paired mesoscale cyclones and anticyclones in spatial proximity (<200 km apart) in the North Pacific Subtropical Gyre. While previous studies have demonstrated that upwelling associated with the intensification of cyclonic eddies can supply nutrients supporting plankton productivity, we observed that steeper vertical gradients in inorganic nutrients increased nutrient fluxes due to diapycnal mixing during the mature stage of cyclonic eddies. The increased diapycnal nutrient supply was linked with expansion of eukaryotic phytoplankton biomass and intensification of the deep chlorophyll maximum (DCM) layer. This perturbation in the plankton community was associated with increased fluxes of biominerals (specifically particulate inorganic carbon and particulate silica) and isotopically enriched organic nitrogen in particles exported in the cyclone. The time‐integrated effects of thermocline vertical displacements on the lower euphotic zone were predictable deficits and surpluses of inorganic nutrients and dissolved oxygen, respectively. However, the stoichiometry of oxygen and inorganic nutrients differed from that predicted for production and consumption of phytoplankton biomass, requiring additional biological processes that decouple changes in oxygen and nutrient concentrations. The dynamics revealed by this study may be a common feature of oligotrophic ecosystems, where mesoscale biogeochemical perturbations are buffered by the DCM layer, which limits the ecological impact of eddies in the well‐lit, near‐surface ocean.

Swell-driven sediment resuspension in the Yangtze Estuary during tropical cyclone events

Tropical-cyclone-induced waves in coastal waters are considered to greatly influence sediment resuspension. Much attention has been paid to the effect of mixed waves (wind waves and swells) during tropical cyclone events. However, little is known about the difference between the effects of swells (driven by offshore tropical cyclones) and wind waves (generated by local winds) on coastal sediment resuspension. In this study, field observations including waves, currents, and suspended sediment concentrations (SSCs) were obtained at an offshore station (mean water depth 20 m) in the Yangtze Estuary, China, during tropical cyclones Meranti and Malakas in 2016. These two tropical cyclones caused the bed shear stress derived from swells (τs) to increase by 5.5–9.5 times relative to the values in calm weather (average τs increased from 0.011 – 0.053 N/s2 to 0.077–0.372 N/s2). The impact of swells on sediment resuspension was much greater than that of wind waves during these two tropical cyclones. The tide-averaged τs (0.011–0.372 N/s2) was 3–16 times greater than the shear stress derived from wind waves (0.003–0.056 N/s2) during the two tropical cyclones. The SSCs was found to have increased by ∼7.5 times (from 0.056 to 0.473 kg/m3) even when tropical cyclones with wind speeds of >41 m/s near their centers occurred 500–1500 km away from the observation station. We estimate that there are on average at least eight tropical cyclones each year that may influence the subaqueous Yangtze Delta by means of swells, considering the impact of remote tropical cyclones. These findings indicate that the swells induced by tropical cyclones play an important role in sediment resuspension in open China coasts, which contributes to our understanding of the influence of swells on coastal sediment resuspension during tropical cyclones.

The impact of atmospheric Rossby waves and cyclones on the Arctic sea ice variability

The Arctic sea-ice extent has strongly declined over recent decades. A large inter-annual variability is superimposed on this negative trend. Previous studies have emphasised a significant warming effect associated with latent energy transport into the Arctic region, in particular due to an enhanced greenhouse effect associated with the convergence of the humidity transport over the Arctic. The atmospheric energy transport into the Arctic is mostly accomplished by waves such as Rossby waves and cyclones. Here we present a systematic study of the effect on Arctic sea ice of these atmospheric wave types. Through a regression analysis we investigate the coupling between transport anomalies of both latent and dry-static energy and sea-ice anomalies. From the state-of-the-art ERA5 reanalysis product the latent and dry-static transport over the Arctic boundary (70^{circ } N) is calculated. The transport is then split into transport by planetary and synoptic-scale waves using a Fourier decomposition. The results show that latent energy transport as compared to that of dry-static shows a much stronger potential to decrease sea ice concentration. However, taking into account that the variability of dry-static transport is of an order of magnitude larger than latent, the actual impact on the sea ice appears similar for the two components. In addition, the energy transport by planetary waves causes a strong decline of the sea ice concentration whereas the transport by synoptic-scale waves shows only little effect on the sea ice. The study emphasises the importance of the large-scale waves on the sea ice variability.

Flood Mapping in Mozambique Using Copernicus Sentinel-2 Satellite Data

Over the last two decades, Mozambique has experienced tremendous tropical cyclonic activities causing many flooding activities accompanied by disastrous human casualties. Studies that integrate remote sensing, elevation data and coupled with demographic analysis in Mozambique are very limited. This study seeks to fill the void by employing satellite data to map inundation caused by Tropical Cyclones in Mozambique. In pursuit of this objective, Sentinel-2 satellite data was obtained from the United States Geological Survey (USGS)’s Earth Explorer free Online Data Services imagery website covering the months of March 20, 2019, March 25, 2019, and April 16, 2019 for two cities, Maputo and Beira in Mozambique. The images were geometrically corrected to remove, haze, scan lines and speckles, and then referenced to Mozambique ground-based Geographic: Lat/Lon coordinate system and WGS 84 Datum. Data from twelve spectral bands of Sentinel-2 satellite, covering the visible and near infrared sections of the electromagnetic spectrum, were further used in the analysis. In addition, Normalized Difference Water Index (NDWI) within the study area was computed using the green and near infrared bands to highlight water bodies of Sentinel-2 detectors. To project and model the population of Mozambique and see the impact of cyclones on the country, demographic data covering 1980 to 2017 was obtained from the World Bank website. The Exponential Smoothing (ETS) method was adopted to forecast the population of Mozambique. Results from NDWI analysis showed that the NDWI is higher for flood areas and lower for non-flooded ones. The ETS algorithm results indicate that the population of Mozambique would nearly double by 2047. Human population along the coastal zone in the country is also on the rise exponentially. The paper concludes by outlining policy recommendations in the form of uniform distribution of economic activities across the country and prohibition of inland migration to the coastal areas where tropical cyclonic activities are very high.

The Impact of Tropical Cyclones on Income Inequality in the U.S.: An Empirical Analysis

The Impact of Tropical Cyclones on Income Inequality in the U.S.: An Empirical Analysis

Focusing and Defocusing of Tropical Cyclone Generated Waves by Ocean Current Refraction

AbstractWaves generated by tropical cyclones can have devastating effects on coastal regions. However, the role of ocean currents in modifying wave amplitudes, wavelengths, and directions is commonly overlooked in wave forecasts, despite the fact that these interactions can lead to extreme wave conditions. Here, we use satellite observations and wave modeling to quantify the effects of ocean currents on the surface waves generated during a tropical cyclone event in the Arabian Sea. As a case study, this paper documents beams of wave heights originating from the eyewall of a tropical cyclone caused by current‐induced refraction. Alternating regions of high and low wave heights in the model simulations are consistent with observations and extend for thousands of kilometers all the way to 100 m isobath. Our results highlight the importance of accounting for wave refraction by currents in order to accurately predict the impact of tropical cyclone generated waves on coastal regions.

The Impact of Tropical Cyclones and Water Conservancy Projects on Island's Flash Floods

The Impact of Tropical Cyclones and Water Conservancy Projects on Island's Flash Floods

Integrated Runoff-Storm Surge Flood Hazard Mapping Associated with Tropical Cyclones in the Suburbs of La Paz, Baja California Sur, México

Floods are amongst the most frequent and destructive type of disaster, causing significant damage to communities. Globally, there is an increasing trend in the damage caused by floods generated by several factors. Flooding is characterized by the overflow of water onto dry land. Tropical cyclones generate floods due to excess water in rivers and streams and storm surges; however, the hazard of both phenomena is presented separately. In this research we present a methodology for the estimation of flood hazards related to tropical cyclones, integrating runoff and storm surge floods. As a case study, we selected the south-western suburbs of the city of La Paz, the capital of the state of Baja California Sur in northwest Mexico. The city has experienced in recent years an expansion of the urban area. In addition, there is an infrastructure of great importance such as the transpeninsular highway that connects the capital with the north of the state, as well as the international airport. Our results indicate that urban areas, agricultural lands, as well as the air force base, airport, and portions of the transpeninsular highway are in hazardous flood areas, making necessary to reduce the exposure and vulnerability to these tropical cyclone-related events. A resulting map was effective in defining those areas that would be exposed to flooding in the face of the impact of tropical cyclones and considering climate change scenarios, which represents an invaluable source of information for society and decision-makers for comprehensive risk management and disaster prevention.

A study of tropical cyclone impact on the power distribution grid in South Korea for estimating damage

Extreme weather events such as tropical cyclones (TC) are considered the most significant weather events causing severe damage to the power distribution grid. However, few or no studies have been performed at the perspectives of the power system although it is necessary, but a relevant study has recently received attention in South Korea. Accordingly, the motivation of this paper addresses the need to present a study of the impact of TCs, focusing on the analysis and the estimation of TC-induced damage. The study uses three sets of historical data: TC data, power distribution grid damage data, and local weather data from 2008 to 2018. Using these data, first, this paper provides an overview of the damage characteristics to understand power system damage. TC, local weather, and TC-induced damage data are analyzed to find their correlated characteristic. Then, TCs are classified by their track patterns associated with the damage characteristic. The importance of TC track is proved by the significance test and comparing the damages by TC tracks. Furthermore, the underlying key hazard variables (i.e., TC and local weather variables) associated with TC-induced damages are identified. Lastly, this paper proposes a multi-stage damage estimation methodology to evaluate the intensity of TC-induced damages using identified major TCs and local weather variables as well as TC tracking information. Therefore, this study will provide useful insights to assess TC-induced damages from the power system perspective in South Korea.

Impact of Tropical cyclones on pelagic Sargassum

Impact of Tropical cyclones on pelagic Sargassum

On the Use of Ensemble Predictions for Parametric Typhoon Insurance

Parametric typhoon insurances are an increasingly used financial tool to mitigate the enormous impact of tropical cyclones, as they can quickly distribute much-needed resources, e.g., for post-disaster recovery. In order to optimise the reliability and efficiency of parametric insurance, it is essential to have well-defined trigger points for any post-disaster payout. This requires a robust localised hazard assessment for a given region. However, due to the rarity of severe, landfalling tropical cyclones, it is difficult to obtain a robust hazard assessment based on historical observations. A recent approach makes use of unrealised, high impact tropical cyclones from state-of-the-art ensemble prediction systems to build a physically consistent event set, which would be equivalent to about 10,000 years of observations. In this study, we demonstrate that (1) alternative trigger points of parametric typhoon insurance can be constructed from a local perspective and the added value of such trigger points can be analysed by comparing with an experimental set-up informed by current practice; (2) the estimation of the occurrence of tropical cyclone-related losses on the provincial level can be improved. We further discuss the potential future development of a general tropical cyclone compound parametric insurance.

Sensitivity of different physics schemes using WRF model in Typhoon Damrey (2017) over the Indochina region

To reduce the tropical cyclone impact of lives and economics, the precise forecast of the event is required. The typhoon Damrey (2017), which caused ravaging of the strong wind, heavy precipitation, flash flood and storm surge over the Indochina region, was simulated by Weather Research and forecasting (WRF) model. The simulated duration was 8 days starting from 31 October 2017 00 00 UTC to 8 November 2017 00 00 UTC. The NCEP 6-hour global FNL (final analysis) data at 1-degree resolution is provided for initial condition. The WRF model was run in a single domain of 20 km horizontal resolution bounded 0 to 20 N and 96°E to 124°E. The different physics schemes, which are the microphysics schemes, the planetary boundary layer schemes and cumulus parameterization schemes, were emphasized to examine the suitable schemes in tropical cyclone simulation over the Indochina region. To evaluate the reliability of the simulation of tropical cyclone, the track-position is correlated with the Japan Meteorological Agency (JMA) observation. The results show that the typhoon simulation forced by Belts-Millers-Janjic cumulus, WSM6 microphysics was suitable for simulating of typhoon Damrey.