ARTICLE | doi:10.20944/preprints201810.0344.v2
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: cyclone; cyclone shelter; evacuation; network analysis; Bangladesh
Online: 22 October 2018 (10:48:49 CEST)
Evacuation is the primary and most important preparedness initiative to save people from the devastating effects of a cyclone. For proper evacuation, a route is specifically chosen that will play a role during cyclones. In this study, Geographic information system has been applied for evacuation route planning for Mirzaganj Union, Patuakhali, Bangladesh. The study is based on questionnaire surveys; direct observation and literature review on the existing sheltering system and develops an evacuation route using the shortest distance analysis. This study provides us an idea how we can manage our population to find out suitable nearby shelters and the limitations that we should focused on. The result shows that only 12% of the total population gets shelter opportunity with the existing official shelter capacity by identifying evacuation route with the shortest distance and the shortest time needed. Shortest distance and time have been calculated for each cyclone shelters. If we consider the low vulnerable infrastructures as shelter, 75% of the total population can be accommodated. This study demonstrates the utilization of an ideal evacuation route planning in the coastal parts of Bangladesh.
ARTICLE | doi:10.20944/preprints201810.0196.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: WRF; Medicane; extra-tropical cyclone; hybrid cyclone; sensitivity analysis
Online: 10 October 2018 (03:43:36 CEST)
Towards the investigation and further understanding of the development and propagation of Medicanes, this study explores the forecasting capability of WRF model in case of cyclone “Cleopatra” which affected with extreme rainfall and strong winds Sardinia and Calabria, Italy, in November 2013. This cyclone was unusual in that it developed a warm core but did not fulfill its transformation into a tropical-like cyclone because its core did not expand high enough in the tropospnere. The ERA5 reanalysis dataset was dynamically downscaled from 31 km spatial horizontal resolution to 9 km using WRF model. The methodology consists of; firstly, an extensive physical parameterization schemes sensitivity test and consequently, a short-range ensemble forecasting implementation based on the highest statistical scored physics configuration. All simulation results were validated against surface observations and remote sensing products. Subsequently, the modeled cyclone trajectories are compared to satellite imagery derived from EUMETSAT-SEVIRI gridded data. The findings of the conducted analysis illustrate that ensemble average displays significant difference in performance compared to any of the deterministic runs individually, suggesting that ensemble forecasts will be beneficial in studies assessing cyclonic events in the Mediterranean region.
SHORT NOTE | doi:10.20944/preprints202007.0033.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: COVID19; Cyclone; Aerosols; Lockdown; Climate
Online: 3 July 2020 (12:06:09 CEST)
The world witnessed one of the largest lockdowns in the history of mankind ever, spread over months in an attempt to contain the contact spreading of the novel coronavirus induced COVID-19. As billions around the world stood witness to the staggered lockdown measures, a storm brewed up in the urns of the rather hot Bay of Bengal (BoB) in the Indian Ocean realm. When Thailand proposed the name “Amphan” (pronounced as “Um-pun” meaning ‘the sky’), way back in 2004, little did they realize that it was the christening of the 1st super cyclone (Category-5 hurricane) of the century in this region and the strongest on the globe this year. At the peak, Amphan clocked wind speeds of 168 mph (Joint Typhoon Warning Center) with the pressure drop to 925 h.Pa. What started as a depression in the southeast BoB at 00 UTC on 16th May 2020 developed into a Super Cyclone in less than 48 hours and finally made landfall in the evening hours of 20th May 2020 through the Sundarbans between West Bengal and Bangladesh. Did the impact of the COVID-19 induced lockdown drive an otherwise typical pre-monsoon tropical depression into a super cyclone?
COMMUNICATION | doi:10.20944/preprints202312.0165.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: tropical cyclone; track; intensity; wind; rainfall
Online: 4 December 2023 (11:35:44 CET)
Hong Kong was under the direct hit of Severe Typhoon Koinu (2314) on 8 and 9 October 2023, necessitating the issuance of the Increasing Gale or Storm Signal, No. 9. Koinu was a very challenging case for TC forecasting and warning services due to its compact size and erratic movement over the northern part of the South China Sea. This paper reviews the difficulties and challenges on the forecasting aspect of the severe typhoon. The predicted tropical cyclone track and intensity from both conventional models and emerging artificial intelligence models are examined, as well as local wind and rainfall forecast. Experience in this case study showed that while deterministic global models only performed moderately and were not able to adequately support early warning, a regional model and AI models could more effectively support decision making for operational tropical cyclone warning service.
ARTICLE | doi:10.20944/preprints202310.0749.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: tropical cyclone; ENSO; ACE; SST; SSH
Online: 12 October 2023 (05:11:55 CEST)
Tropical cyclones (TC) are one of the deadliest natural meteorological hazards and the most frequent cause of natural disasters. The El-Niño Southern Oscillation (ENSO), a tropical ocean-atmosphere interaction, is known to significantly impact cyclonic systems over global ocean basins. This study investigates the variability of TC activity in presence of ENSO over the North Indian Ocean (NIO), comprising of the Arabian Sea (ARB) and the Bay of Bengal (BOB) basins during the pre- and post-monsoon season, using accumulated cyclone energy (ACE) over the last 26 years. Our analysis reveals a significant rise in cyclone intensity over the past two decades, with eight of the ten most active years occurring since the 2000s. Total ACE over the NIO is found to be higher in La-Niña. Higher ACE observed over ARB is strongly associated with a combination of elevated sea surface height (SSH) anomaly and low vertical wind shear during the El-Niño episodes, with higher sea surface temperatures (SST) during the post-monsoon season. Whereas in the BOB, El Niño not only reduces ACE but also decreases basin-wide variability, and more pronounced effect during the post-monsoon season, coinciding with warmer SST and higher SSH along the coast during La-Niña.
COMMUNICATION | doi:10.20944/preprints202309.1634.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: tropical cyclone; track; intensity; wind structure
Online: 25 September 2023 (09:32:43 CEST)
Hong Kong was under strike from Super Typhoon Saola (2309), necessitating the issuance of the highest tropical cyclone warning signal. Saola skirted past the south-southwest of Hong Kong, bringing hurricane force winds and significant storm surge. Saola had its closest approach to Hong Kong on 1 September 2023, posing a unique challenge in forecasting and early warning for the commencement date of the new school term, where higher impact to traffic and public safety was anticipated. This paper covers the challenges on the forecasting aspect of the super typhoon. The predicted tropical cyclone track, intensity and wind structure are reviewed. Experience in this case showed that while there was not a perfect numerical weather prediction model in terms of the forecast track, intensity and wind structure of Saola, multi-model approach provided very use-ful and crucial information for operational weather warning services.
REVIEW | doi:10.20944/preprints202304.0786.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: Tropical cyclone; hurricane; turbulence; convection; Rayleigh-Benard
Online: 23 April 2023 (07:38:59 CEST)
Tropical cyclones have long been known to be powered by turbulent enthalpy fluxes from the ocean surface and retarded by turbulent momentum fluxes into the surface. Here were review evidence that the development and structure of these storms are also partially controlled by turbulence in the outflow near the storm top. Finally, we present new research that shows that tropical cyclone-like, low-aspect-ratio vortices are most likely in systems in which the bottom heat flux is controlled by mechanical turbulence and the top boundary is insulating.
COMMUNICATION | doi:10.20944/preprints202309.1683.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: tropical cyclone; aircraft data; turbulence; eddy dissipation rate
Online: 25 September 2023 (11:26:19 CEST)
In situ aircraft observations in typhoons have been scarce. This paper documents and analyses the aircraft and dropsonde data collected in Super Typhoon Saola (2023) over the northern part of the South China Sea. The wind and turbulence structures of the typhoon are investigated. The turbulence intensities are quantified in terms of turbulent kinetic energy (TKE) and eddy dissipate rate (EDR), and these data are compared with other available estimates of turbulence intensities, such as those based on weather radars, meteorological satellites, and numerical weather predic-tion (NWP) models. It is found that the TKE and EDR are closely correlated, and they are con-sistent with the weather radar/satellite observations as well as NWP-based outputs. Furthermore, the boundary layer inflow, vertical wind profiles, and atmospheric stability are analysed based on the dropsonde observations. The analysed results would advance the understanding of typhoon structures and offer references for the validation of remote sensing observations and NWP models.
COMMUNICATION | doi:10.20944/preprints202309.1688.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: tropical cyclone; radar wind profiler; LIDAR; weather radar; microburst
Online: 26 September 2023 (05:21:59 CEST)
Super Typhoon Saola came very close to Hong Kong on 1 and 2 September 2023, necessitating the issuance of No. 10 hurricane signal, the highest tropical cyclone warning signal, in Hong Kong. While there were widespread damages in Hong Kong, no people were killed in the event with effective early warning. It is rare that a super typhoon came very close to Hong Kong and this paper is the first part in the series of the documentation of Saola to summarize the interesting observations of Saola near Hong Kong for future reference by weather forecasters, including sur-face observations, upper air observations, microburst alert from weather radars, and turbulence intensity based on spectral width measurement of radars.
ARTICLE | doi:10.20944/preprints202303.0531.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: bifurcation; cyclone; forks; hurricane; tree biomechanics; tree risk assessment; typhoon
Online: 30 March 2023 (12:55:40 CEST)
Practitioners who assess the risk associated with urban trees often factor in the presence or absence of visual tree defects when determining whether a tree may fail. While these defects are a main fixture in many tree risk assessment systems and best management practices, the research supporting their usefulness in predicting tree failure during storms is limited. When looking at past research involving populations of storm-damaged trees, there are several defects that have never predicted failure (or have been associated with reduced rates of failure). In this study, we took a closer look at four such defects: codominant branches; branch unions with included bark; multiple stems originating from the same point; and overextended branches. After Hurricane Ian, we revisited 1519 risk assessed trees where one of these four defects was identified as the primary condition of concern. Fourteen of these trees experienced branch failure during the storm (which hit the study area as a downgraded tropical storm). Upon closer inspection, none of these failures occurred at the defect of concern. Our findings indicate that none of the defects assessed appeared to increase the likelihood of tree failure in the species tested. Our results are in line with past research on these defects derived from post-storm assessments and analysis.
ARTICLE | doi:10.20944/preprints201911.0125.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: tropical cyclone; Weather Research and Forecast model; zonal Ekman transport
Online: 12 November 2019 (09:32:21 CET)
We examine the role of zonal Ekman transport along the coast of Senegal on 30 August, 2015 when the tropical disturbance associated with Tropical Cyclone Fred was located to the west of Senegal causing considerable coastal damage to coastal areas south of Dakar, Senegal. Ten-meter winds from three Weather Research and Forecast model simulations were used to estimate zonal Ekman transport, with the largest values found during the 30 August. The simulations are in agreement with limited coastal observations showing increasing southerly wind speeds during 30 August but are overestimated relative to the 3 coastal stations. The strong meridional winds translate into increased zonal Ekman transport to the coast of Senegal on 30 August. The use of a coupled ocean model will improve the estimates of Ekman transport along the Guinea-Senegalese coast. The observed damage suggests that artificial and natural barriers (mangroves) should be strengthened to protect coastal communities in Senegal.
ARTICLE | doi:10.20944/preprints202107.0534.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: governance; social-ecological system; tropical cyclone; urban forest; urban tree canopy
Online: 23 July 2021 (10:31:50 CEST)
Urban Tree Canopy (UTC) greatly enhances the livability of cities by reducing urban heat buildup, mitigating stormwater runoff, and filtering airborne particulates, among other ecological services. These benefits, combined with the relative ease of measuring tree cover from aerial imagery, have led many cities to adopt management strategies based on UTC goals. In this study, we conducted canopy analyses for the 300 largest cities in Florida to assess the impacts of development practices, urban forest ordinances, and hurricanes on tree cover. Within the cities sampled, UTC canopy ranged from 5.9% to 68.7% with a median canopy coverage of 32.3% Our results indicate that the peak gust speeds recorded during past hurricanes events were a significant predictor of canopy coverage (P-value = <0.001) across the sampled cities. As peak gust speeds increased from 152 km/h (i.e., a lower-intensity Category 1 storm) to 225 km/h (lower-intensity Category 4 and the maximum gusts captured in our data), predicted canopy in developed urban areas decreased by 7.7%. Beyond the impacts of hurricanes and tropical storms, we found that historic landcover and two out of eight urban forest ordinances were significant predictors of existing canopy coverage (P-landcover <0.001; P-tree preservation ordinance = 0.02, P-heritage tree ordinance = 0.03). Results indicate that local policies and tree protections can protect or enhance urban tree canopy, even in the face of rapid development and periodic natural disturbances.
ARTICLE | doi:10.20944/preprints201905.0151.v1
Subject: Business, Economics And Management, Economics Keywords: climate change; adaptation; loss & damage; damage function; return period; tropical cyclone
Online: 13 May 2019 (10:07:41 CEST)
This paper constructs a model of climate-related damage for small island developing states (SIDS). We focus on the loss of private productive capital stocks through extreme climate events. In contrast to most economic analyses of climate impacts, which assume temperature-dependent damage functions, we draw on the engineering literature to allow for a greater or lesser degree of anticipation of climate change when designing capital stocks and balancing current adaptation expenditure against future loss & damage. We apply the model to tropical storm damage in the small island developing state of Barbados and show how anticipatory behavior changes the damage to infrastructure for the same degree of climate change. Thus, in the model, damage depends on behavior as well as climate variables.
ARTICLE | doi:10.20944/preprints202011.0187.v1
Subject: Engineering, Mechanical Engineering Keywords: Cyclone separator; Computational fluid dynamics (CFD); Machine learning; Unsteady RANS; Critical Diameter
Online: 4 November 2020 (10:11:58 CET)
This paper deals with the characteristics of the cyclone separator from the Lagrangian perspective to design important dependent variables, develops a neural network model for predicting the separation performance parameter, and compares the predictive performance between the traditional surrogate model and the neural network model. In order to design the important parameters of the cyclone separator based on the particle separation theory, the force acting until the particles are separated was calculated using the Lagrangian-based CFD methodology. As a result, it was proved that the centrifugal force and drag acting on the critical diameter having a separation efficiency of 50% were similar, and the particle separation phenomenon in the cyclone occurred from the critical diameter, and it was set as an important dependent variable. For developing a critical diameter prediction model based on machine learning and multiple regression methods, Unsteady-RANS analyzes according to shape dimensions were performed. The input design variables for predicting the critical diameter were selected as four geometry parameters that affect the turbulent flow inside the cyclone. As a result of comparing the model prediction performances, the ML model showed the 32.5 % of improvement rate of R2 compared to the traditional MLR considering the nonlinear relationship between the cyclone design variable and the critical diameter. The proposed techniques have proven to be fast and practical tools for cyclone design.
ARTICLE | doi:10.20944/preprints202205.0282.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: cyclone; defect; hurricane; likelihood of failure; storm damage; typhoon; urban ecology; urban forestry
Online: 21 May 2022 (11:03:18 CEST)
Urban trees are often more sun- and wind-exposed than their forest-grown counterparts. These environmental differences can impact how many species grow – impacting trunk taper, crown spread, branch architecture, and other aspects of tree form. Given these differences, windthrow models derived from traditional forest production data sources may not be appropriate for urban forest management. Additionally, visual abnormalities historically labeled as “defects” in timber production may not have a significant impact on tree failure potential. In this study, we look at urban tree failures associated with Hurricane Irma in Tampa, Florida, USA. We used spatial analysis to determine if patterns of failure existed among our inventoried trees. We also looked at risk assessment data to determine which visual defects were the most common and the most likely to be associated with branch or whole-tree failure. Results indicate that there was no spatial pattern associated with the observed tree failures – trees failed or withstood the storm as individuals. While some defects like decay and dead wood were associated with increased tree failure, other defects like weak branch unions and poor branch architecture were less problematic.
ARTICLE | doi:10.20944/preprints201804.0336.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: typhoon Durian; tropical cyclone; wind-pressure relationships; South China Sea; sensitivity analysis; WRF
Online: 26 April 2018 (08:59:09 CEST)
Typhoon Durian forming over the Western North Pacific Ocean and entering into the South China Sea (SCS), caused extreme and widespread damages in 2006. In this research, sensitivity analyses on different physical parameterization schemes of the Weather Research and Forecasting Atmospheric Model (WRF-ATM) have been utilized to study typhoon Durian. Model accuracy and performance testing were investigated with different initial conditions during the tropical cyclone simulation in the SCS. The initial and boundary conditions (IBCs) for all experiments were derived from the European Centre for Medium Range Weather Forecasts (ECMWF), Re-Analysis Interim (ERAI), and the National Centers for Environmental Prediction (NCEP) with Final (FNL) analysis data compiled through the WRF-ATM model. The sensitivity analysis results indicated a major improvement for the cumulus scheme by using the Grell-Devenyi scheme along with the PBL scheme of Yonsei University, mixed-phase microphysics scheme of the WRF Single Moment 5-class and IBCs for ECMWF-ERAI of TC simulation under the context of Wind-Pressure Relationships. This predicted better track and intensity comparing with these of the Joint Typhoon Warning Center. The results revealed that the TC track and intensity were well simulated by the WSM5-GD combination for the WRF-ATM model with an intensity error of 1.69 hPa for minimum surface level pressure, maximum wind speed of 1.83 knots and average track error of 25 km in 72 hours. The simulations showed that the potential track and intensity error decreased with the delayed IBCs, suggesting that the model simulation is more dependable when the coast is approached by the TC.
ARTICLE | doi:10.20944/preprints202006.0077.v1
Subject: Engineering, Marine Engineering Keywords: underwater wireless optical communication (UWOC); radiative transfer equation solver; optical path loss; tropical cyclone
Online: 7 June 2020 (10:01:08 CEST)
Underwater wireless optical communications (UWOC) have attracted considerable attention in recent years as an alternative means for acoustic communication. However, optical path loss of light propagation from attenuation is large due to absorption and scattering in various water conditions. Identification of environmental effects especially tropical storms on underwater optical path loss is the key to the success of using optics for UWOC. Underwater inherent optical properties (IOPs) such as the beam attenuation coefficient for 470 nm light in the western North Pacific Ocean were measured from the U.S. Naval Oceanographic Office sea gliders with being deployed after Super Typhoon Guchol (7-20 June 2012)‘s passage during 25-30 June 2012 and no any typhoon passage during 9 January – 28 February 2014. The observed two sets (with and without super typhoon) of IOPs are taken as input into a recently developed Radiative Transfer Equation solver. The simulated normalized received powers for the two durations show large impact of typhoon passage on UWOC.
ARTICLE | doi:10.20944/preprints202105.0631.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: Western Cape; Southern Annular Mode; Circulation type; Africa south of the equator; mid-latitude cyclone
Online: 26 May 2021 (11:04:08 CEST)
This study investigates circulation types (CTs) in Africa, south of the equator, that are related to wet and dry conditions in Western Cape, the statistical relationship between the selected CTs and the Southern Annular Mode (SAM), and changes in the frequency of occurrence of the CTs related to the SAM under the ssp585 scenario. Obliquely rotated principal component analysis applied to sea level pressure was used to classify CTs in Africa, south of the equator. Three CTs were found to have a high probability to be associated with wet days in Western Cape, and four CTs were equally found to have a high probability to be associated with dry days in Western Cape. Generally, the dry/wet CTs feature the southward/northward track of the mid-latitude cyclone, adjacent to South Africa; anti-cyclonic/cyclonic relative vorticity, and poleward/equatorward track of westerlies, south of South Africa. One of the selected wet CTs is significantly related to variations of the SAM. Years with an above-average SAM index correlate with the below-average frequency of occurrence of the wet CT. The results suggest that through the dynamics of the CT, the SAM might control the rainfall variability of Western Cape. Under the ssp585 scenario, the analyzed climate models indicated a possibility in the decrease of the frequency of occurrence of the aforementioned wet CT associated with cyclonic activity at the mid-latitudes, and an increase in the frequency of occurrence of the CT associated with enhanced SLP in the mid-latitudes.
ARTICLE | doi:10.20944/preprints201907.0185.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: summer-mean Arctic circulation patterns; extra-tropical synoptic cyclones; self-organizing maps (SOMs); cyclone detection and tracking
Online: 15 July 2019 (15:24:28 CEST)
The contribution of extra-tropical synoptic cyclones to the formation of summer-mean atmospheric circulation patterns in the Arctic is investigated by clustering the dominant Arctic circulation patterns by the self-organizing maps (SOMs) using the daily mean sea level pressure (MSLP) in the Arctic domain (≥ 60°N). Three SOM patterns are identified: one with prevalent low pressure anomalies in the Arctic Circle (SOM1) and two opposite dipoles with primary high pressure anomalies covering the Arctic Ocean (SOM2 and SOM3). The time series of summertime occurrence frequencies demonstrate the largest inter-annual variation in the SOM1, the slight decreasing trend in the SOM2, and the abrupt upswing after 2007 in the SOM3. The relevant analyses with produced cyclone track data confirm that the vital contribution. The Arctic cyclone activity is enhanced in the SOM1 because the meridional temperature gradient increases over the land–Arctic Ocean boundaries co-located with major extra-tropical cyclone pathways. The composite daily synoptic evolutions for each SOM reveal that the persistence of all the three SOMs is less than 5 days on average. These evolutionary short-term weather patterns have substantial variability at inter-annual and longer timescales. Therefore, the synoptic-scale activity is central to forming the seasonal-mean climate of the Arctic.
ARTICLE | doi:10.20944/preprints202304.0059.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: Quantum of action; action mechanics; least action; photons; quanta; Gibbs energy; Gibbs field; torque; vortical action; Carnot cycle; wind turbines; downwelling radiation; tropical cyclone; gravitational energy
Online: 5 April 2023 (11:48:53 CEST)
We propose that, at equilibrium, statistically equal temperatures as mechanical torques are exerted on each kind of gas phase molecules as rates of translational action [@t=ʃmvds/dt=ʃmr2ωdϕ/dt=mv2, J]. These torques result from the impulsive density of resonant quantum fields with molecules, configuring the trajectories of gas molecules while balancing molecular pressure (p=NkT) against the density of field energy (J/m3). Gibbs energy fields contain no resonant quanta at zero Kelvin, with this measure of chemical potential diminishing in magnitude as translational action of the vapor molecules and quantum field energy increases with temperature. In illustration, we show how impulsive torques from quantum fields drive the reversible thermodynamics of Carnot’s heat-work engine cycle, sustain the decreasing atmospheric temperature gradient of increasing molecular entropy with altitude, support the translational action and field energy of vortical wind flow in anticyclones, frictionally warming the Earth’s surface while recycling greenhouse infrared absorption of surface radiation, generating electrical power from air flow in wind farms and destructive power in tropical cyclones. These cases all distinguish symmetrically between a causal field of impulsive quanta (Σhν) that energizes the action of matter and the resultant vis viva of molecular mechanics (mv2). The quanta of these different fields display mean wavelengths from 10-4 m to 1012 m, with mechanical advantages many orders of magnitude greater than the corresponding translational actions, though with mean quantum frequencies (v) similar to those of radial Brownian movement for independent particles (ω). These energy fields are also thermodynamically reversible reservoirs for heat, optimizing work processes on Earth and delaying the achievement of maximum entropy production from short wave solar radiation in conversion to outgoing long wave radiation to space.