Accurate forecasting and up-to-date warning is very important for the coastal people to protect them from the devastation of cyclone. Bangladesh Meteorological Department (BMD) and their concern organizations have important role to provide proper and accurate cyclone forecasting and warning message to the people. The coastal zone of the country is the most precarious place to natural disaster due to its geographical location, frequent formation of cyclone in the Bay, poor infrastructure and insecure socio-economic conditions of the people.  Accurate and timely warning, good infrastructure such as roads, transportations, cyclone shelters, cyclone preparedness training centers can reduce  human vulnerability to cyclone in the coastal area of the country. Due to very high population growth rate in the coastal zone, new settlements are being built in the areas which were under agricultural land, forest or bare before. To study the people’s perceptions on cyclone forecasting, warning and management system in Bangladesh, two questionnaire surveys have been done, one with meteorologists of BMD and the other with the people living in the coastal zone. As land use change has great impact on human vulnerability to disaster so, a brief study on land-use change has also been done under the current research.   Keywords: Cyclone, forecasting technique, questionnaire survey, Natural hazards and Land- use change.

Wavelike spiral asymmetries are an intriguing aspect of Tropical Cyclone dynamics. Previous work hypothesized that some of them are Vortex Rossby Waves propagating on the radial gradient of mean–flow relative vorticity. In the Intermittently Forced Vortex Rossby Wave theory, intermittent convection near the eyewall wind maximum excites them so that they propagate wave energy outward and converge angular momentum inward. The waves’ energy is absorbed as the perturbation vorticity becomes filamented near the outer critical radii where their Doppler–shifted frequencies and radial group velocities approaches zero. This process may initiate outer wind maxima by weakening the mean–flow just inward from the critical radius. The waves are confined to a relatively narrow annular waveguide because of their slow tangential phase velocity and the narrow interval between the Rossby wave cut–off frequency, where the radial wavenumber is locally zero, and the zero frequency, where it is locally infinite.

At the begining of this thesis radar theory and classification of radar systems is explained. Next part introduces antenna arrays with it’s parameters and possibilities. Main part contains design of digital beamformer on FPGA Cyclone V and it’s validation.

Goal of this dissertation is introduce the problem of small dust particles present in the gaseous products of combustion. Further I´m looking technologies cyclone and an electrostatic filter to capture small particles and comparing the effectiveness of separability. Dissertation is concluded by designed cyclone and an electrostatic filter.

Climate modeling and tropical cyclone forecasting are two significant is- sues that are continuously being improved upon for more accurate weather forecasting and preparedness. In this thesis, we have studied three climate models and formulated a new model with a view to determine the outgoing longwave radiation (OLR) budget at the top of the atmosphere (TOA) as ob- served by the National Oceanic and Atmospheric Administration’s (NOAA) satellite based Advanced Very High Resolution Radiometer (AVHRR). In 2006, Karnauskas proposed the African meridional OLR as an Atlantic hur- ricane predictor, the relation was further proven in 2016 by Karnauskas and Li. Here we have considered a similar study for all other tropical cyclone basins.

All humanitarian actors should be accountable to children. In May 2023, Cyclone Mocha ripped through Myanmar, affecting over 3 million people with more than 90 percent of children facing overlapping climate and emergency crisis. Efforts to enhance accountability to children in humanitarian action are urgently needed now more than ever. Despite the highly discussed topic of accountability, there is still little research on accountability of child protection in the humanitarian context. Therefore, the purpose of this study is to dissect the concept of accountability from the Child Protection Minimum Standards in Humanitarian Action (CPMS) guidelines and identify how it can be used to guide accountability to children in Myanmar. From analyzing the case study of Cyclone Mocha, the research found that the CPMS tools can be used to guide accountability to the child protection interventions in four main themes: participation, cross-sector collaboration and programming, evaluation and reporting, and feedback and response mechanisms. The study concluded that the CPMS guidance notes can influence accountability in Myanmar by providing more weight on informal social accountability mechanisms and leveling out the formal upward accountability currently dominating in the child protection intervention systems.

Approved for public release, distribution is unlimited / occurring most frequently. For the 217 large-error cases due to midlatitude influences, the most frequent error mechanisms were E-DCI (midlatitude), excessive response to vertical wind shear, excessive midlatitude cyclogenesis (E-MCG), insufficient midlatitude cyclogenesis (I-MCG), excessive midlatitude cyclolysis (E-MCL) and excessive midlatitude anticyclogenesis (E-MAG), which accounted for 68% of all large errors occurring in both NOGAPS and GFDN. Characteristics and symptoms of the erroneous forecast tracks and model fields are documented and illustrative case studies are presented. Proper identification and removal of the track forecast displaying an error mechanism could form a selective consensus that will be more accurate than a non-selective consensus. / Captain, United States Air Force

Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Tropical cyclones are synoptic scale rotating storms capable of generating intense wind speeds and rainfall with potentially devastating social and economic consequences. In addition to abnormally high winds and rainfall, the associated storm surge and extreme waves can lead to severe coastal erosion, damage to coastal property and inundation. A good understanding of the risk exposure to these events is therefore of great importance to planners and designers of coastal infrastructure in vulnerable regions. Probabilistic approaches have been routinely adopted for the calculation of extreme tropical cyclone induced wind speeds, with significant developments in these techniques over the last few decades. While the application of these approaches has become widely adopted in regions such as the North Atlantic, North Pacific and South Pacific Oceans, relatively little attention has been paid to the South-West Indian Ocean. This thesis focusses on the quantification of the risk exposure to tropical cyclones over the South-West Indian Ocean, using current state-of-the-art techniques. The primary results of the thesis are extreme wind speed maps at various return periods of interest for engineering design. Best track data for the South-West Indian Ocean, as archived by the Joint Typhoon Warning Centre (JTWC), has been used as the primary dataset forming the basis of this study. These data provide estimates of the location and intensity of historical tropical cyclones at six hourly intervals. Location data are provided as estimates of longitude and latitude of the eye, while intensity data are provided as estimates of the maximum sustained surface (10 m elevation) wind speed and/or minimum central pressure. The modelling of tropical cyclone wind fields has been carried out using both the Holland (1980) and the Willoughby et al. (2006) parametric wind field models. Using the limited information available in the best track data as input to the model, surface wind fields which reasonably resemble those of actual storms have been generated. Both considered parametric wind field models have been shown to yield reasonable wind speeds and directions when compared with measurements. Of the two considered models the Willoughby et al. (2006) model has been shown to provide the best fit to historical wind speed measurements. Extreme value analyses of tropical cyclone induced wind speeds based on historical data alone have been shown to lead to potentially large errors, owing to the small sample size of the historical data. This highlights the need to augment the historical database through a probabilistic approach. Largely following the methods described in Powel et al. (2005) and Emanuel et al. (2006), a synthetic track model for the South-West Indian Ocean has been developed. The objective of the synthetic track model is to simulate thousands of years of tropical cyclone tracks, thereby circumventing errors induced by small sample sizes in the available historical best track data. The synthetic track model developed as part of this study is a Markov chain model, capable of simulating track propagation and intensity evolution along the track, from track genesis through to termination. The model is purely statistical, based on properties derived from the historical best track data. Adjustments have however been made to account for physical limitations such as those imposed by the equator and the maximum potential intensity which an event can attain. The statistical characteristics of synthetic tracks have been shown to agree well with those of the historical population. Applying the Willoughby et al. (2006) wind field model along synthetic tracks has enabled the simulation of 5 000 years of tropical cyclone induced wind speeds at any location of interest in the South-West Indian Ocean. Applying calculations on a 1 degree geographical grid, wind speed maps corresponding to return periods of 50, 100, 200 and 500 years have been generated for the South-West Indian Ocean. Extreme wind speeds along coastal regions provide valuable input for the design of coastal infrastructure in the region. / AFRIKAANSE OPSOMMING: Tropiese siklone is sinoptiese orde roterende storms wat in staat is om aansienlike windspoed en reënval, tot gevolg te hê met potensiële vernietigende sosiale en ekonomiese gevolge. Benewens die abnormale sterk winde en hoë reënval kan die verwante stormdeinings en vloedgolwe lei tot ernstige kus-erosie, skade aan kusfront-eiendom en oorstromings. ‘n Goeie begrip van die risiko-blootstelling aan hierdie gebeurtenisse is daarom van groot belang vir die beplanners en ontwerpers van kus-infrastruktuur in kwesbare gebiede. As gevolg van die beduidende ontwikkeling van probabilistiese benadering tot die berekening van windspoed wat veroorsaak word deur ekstreme tropiese siklone, word hierdie tegnieke huidiglike op ‘n roetine basis aangewend. Terwyl die toepassing van hierdie benaderings wyd aanvaar word in gebiede soos die Noord-Atlantiese, Noordelike- en Suidelike Stille Oseaan, word relatief min aandag gegee aan die Suid-Westelike Indiese Oseaan. Hierdie tesis fokus op die kwantifisering van die risiko-blootstelling aan tropiese siklone in die Suid-Westelike Indiese Oseaan met die gebruik van die huidige gevorderdste tegnieke. Die primêre resultaat van die tesis is uiterste wind spoed kaarte vir ‘n verskeindenheid herhaal periodes wat van belang in vir engenieursontwerp. Beste roete-ata vir die Suid-Westelike Indiese Oseaan, soos voorsien deur die Gesametlike Tifoon Waarskuwing Sentrum (JTWC), is gebruik as die primêre data stel wat die basis vorm van hierdie studie. Hierdie data gee die beste skattings van die ligging (lengte- en breedtegraad), en intensiteit (maksimum volgehoue oppervlak (10m hoogte) wind spoed en/of sentrale druk tekort) van historiese tropiese siklone teen ses-uurlikse intervalle. Die modelering van tropiese sikloon windvelde was uitgevoer met die gebruik van die Holland (1980) en die Willoughby et al. (2006) parametriese windveldmodelle. Met die gebruik van beperkte inligting wat beskikbaar is in die beste roete data as invoer vir die model, was oppervlak wind velde gegenereer wat ‘n billike ooreenstemming het met die van werklike storms. Beide tegnieke se parametriese windveldmodelle is al bewys om redelike akkurate windspoed en windrigtings te lewer in vergelyking met waargenome waardes. Van die twee modelle het die Willoughby et al. (2006) model se resultate die beste ooreenstemming gewys met historiese wind spoed metings. Dit is al uitgewys dat uiterste waarde-analises van tropiese sikloon veroorsaakte windspoed moontlik kan lei tot groot foute in die resultate as gevolg van die klein monster-grootte van die historiese data. Dit beklemtoon die noodsaaklikheid om die historiese databasis aan te vul met behulp van probabilistiese metodes. Die metodes soos beskryf deur Powel et al. (2005) en Emanuel et al. (2006) is hoofsaaklik gebruik om ‘n sintetiese roete-model vir die Suid-Westelike Oseaan te ontwikkel. Die doelwit van die sintetiese roete model is om duisende jare se tropiese sikloonroetes te produseer, en in effek foute te vermy as gevolg van die gebruik van klein monster groottes van die beskikbare historiese beste roete data. Die sintetiese roete model wat tydens hierdie studie ontwikkel is, is ‘n Markov kettingmodel wat in staat is om die roete verspreiding asook die evolusie van intensiteit saam die roete te simuleer vanaf die onstaan tot die beëindiging van die sikloon se roete. Die model is suiwer statisties en is gebasseer op die eienskappe soos afgelei vanaf die historiese beste roete data. Aanpassings is gemaak om rekening te hou van die fisiese beperkings soos die wat opgelê word deur die ewenaar en die maksimum potensiële intensiteit wat ‘n sikloon kan bereik. Dit is voorgelê dat die statistiese einskappe van die sintetiese roetes goed saamstem met die van die historiese populasie. Die toepassing van die Willoughby et al. (2006) wind veld model langs die sintetiese roetes het dit moontlik gemaak om 5000 jaar se windspoed, wat veroorsaak is deur tropiese siklone, te genereer by enige ligging wat van belang is in die Suid-Westelike Indiese Oseaan. Met berekeninge wat op ‘n 1 grade geografiese ruitnet gedoen is, is windspoedkaarte vir herhaal periodes van 50, 100, 200 en 500 jaar opgestel vir die Suid-Westelike Indiese Oseaan. Die uiterste wind spoed in kusgebiede gee waardevolle invoer vir die ontwerp van kus-infrastruktuur in die omgewing.

Ciclones são equipamentos largamente empregados na separação de partículas do ar ou na limpeza de gases de processos por ação da força centrífuga. Neste trabalho, um ciclone lavador modificado foi projetado, construído, e sua eficiência de coleta de partículas foi avaliada. O equipamento consiste de um ciclone separador tipo Americano com triplo cone, em cujo corpo cilíndrico foram introduzidos bicos nebulizadores de água. Graças a essa configuração ele pode ser usado em galpões industriais, apresenta facilidade de construção e operação e baixo custo. O autor projetou esse ciclone objetivando não somente a eficiência de coleta, mas também a compacidade, o baixo consumo de água e de eletricidade, a possibilidade de purificação de gases ou vapores tóxicos, e ainda, o resfriamento de gases quentes pela umidificação até a saturação, de acordo com os fundamentos da separação de poeiras empregada nos scrubbers úmidos. O estudo consistiu de uma avaliação experimental das condições de operação à temperaturas ambiente e superiores à ambiente, variando também a altura da chaminé e a vazão de água de umidificação da poeira. Os ensaios foram realizados em duas etapas. Na primeira, objetivou-se identificar as melhores condições de operação usando todo o potencial de variação do equipamento, e empregando um projeto fatorial de três fatores (three-way). A segunda etapa objetivou-se estimar a eficiência de coleta do ciclone lavador usando como poluente, partículas de quartzo micronizado com diâmetro médio de 7,48 µm. A concentração de partículas no gás foi de 20 a 100 mg/m3 de ar. Foi obtida uma eficiência média de 97.07±1.03 %, para 4 bicos nebulizadores, 4 aquecedores em funcionamento e altura da chaminé 645 mm, para uma vazão de gás 0,358 m3/s de gás. Concluindo a modificação do projeto aumento a eficiência de coleta de aproximadamente 70 % ,em ciclones secos, para 97,07 %. / Cyclones are devices widely employed to separate and collect particles from the air or for cleaning up gases for processes by the action of centrifugal force. In this work a modified cyclone washer was designed, fabricated, and its collection efficiency evaluated. This equipment consists of an Americantype cyclone separator with a triple cone into whose cylindrical body a spray nozzle was introduced. Thanks to its configuration, it can be used in industrial warehouses and is fairly simple to build and operate, as well as inexpensive. The author designed this cyclone with a view not only to efficiency but also compactness, low water and electricity consumption, the possibility of toxic gas or vapor absorption, the cooling of hot gases and aerosol humidification up to saturation, according to fundamentals of dust separation with wet scrubbers. The study consisted of an experimental evaluation of the operating conditions at ambient and higher than ambient temperatures, changing the chimney height and water flow rate, with the purpose of humidifying dust. The tests were carried out in two steps. The first step aimed to identify the best operating condition using the entire potential variation and employing a three-way factorial design. The second step aimed to estimate the efficiency of the cyclone washer was evaluated in the collection of micronized quartz particles with an average diameter of 7.48 µm. The amount of particles varied from 20 to 100 mg/m3 of air. An average efficiency of 97.07±1.03 % was obtained with four spray nozzles, with its four heaters turned on, chimney height of 0.645 m and 0.358 m3/s of gas. In conclusion, the design modification had increased the collection efficiency from about 70 %, in dry cyclones, to 97.07 %.

Ciclones são equipamentos largamente empregados na separação de partículas do ar ou na limpeza de gases de processos por ação da força centrífuga. Neste trabalho, um ciclone lavador modificado foi projetado, construído, e sua eficiência de coleta de partículas foi avaliada. O equipamento consiste de um ciclone separador tipo Americano com triplo cone, em cujo corpo cilíndrico foram introduzidos bicos nebulizadores de água. Graças a essa configuração ele pode ser usado em galpões industriais, apresenta facilidade de construção e operação e baixo custo. O autor projetou esse ciclone objetivando não somente a eficiência de coleta, mas também a compacidade, o baixo consumo de água e de eletricidade, a possibilidade de purificação de gases ou vapores tóxicos, e ainda, o resfriamento de gases quentes pela umidificação até a saturação, de acordo com os fundamentos da separação de poeiras empregada nos scrubbers úmidos. O estudo consistiu de uma avaliação experimental das condições de operação à temperaturas ambiente e superiores à ambiente, variando também a altura da chaminé e a vazão de água de umidificação da poeira. Os ensaios foram realizados em duas etapas. Na primeira, objetivou-se identificar as melhores condições de operação usando todo o potencial de variação do equipamento, e empregando um projeto fatorial de três fatores (three-way). A segunda etapa objetivou-se estimar a eficiência de coleta do ciclone lavador usando como poluente, partículas de quartzo micronizado com diâmetro médio de 7,48 µm. A concentração de partículas no gás foi de 20 a 100 mg/m3 de ar. Foi obtida uma eficiência média de 97.07±1.03 %, para 4 bicos nebulizadores, 4 aquecedores em funcionamento e altura da chaminé 645 mm, para uma vazão de gás 0,358 m3/s de gás. Concluindo a modificação do projeto aumento a eficiência de coleta de aproximadamente 70 % ,em ciclones secos, para 97,07 %. / Cyclones are devices widely employed to separate and collect particles from the air or for cleaning up gases for processes by the action of centrifugal force. In this work a modified cyclone washer was designed, fabricated, and its collection efficiency evaluated. This equipment consists of an Americantype cyclone separator with a triple cone into whose cylindrical body a spray nozzle was introduced. Thanks to its configuration, it can be used in industrial warehouses and is fairly simple to build and operate, as well as inexpensive. The author designed this cyclone with a view not only to efficiency but also compactness, low water and electricity consumption, the possibility of toxic gas or vapor absorption, the cooling of hot gases and aerosol humidification up to saturation, according to fundamentals of dust separation with wet scrubbers. The study consisted of an experimental evaluation of the operating conditions at ambient and higher than ambient temperatures, changing the chimney height and water flow rate, with the purpose of humidifying dust. The tests were carried out in two steps. The first step aimed to identify the best operating condition using the entire potential variation and employing a three-way factorial design. The second step aimed to estimate the efficiency of the cyclone washer was evaluated in the collection of micronized quartz particles with an average diameter of 7.48 µm. The amount of particles varied from 20 to 100 mg/m3 of air. An average efficiency of 97.07±1.03 % was obtained with four spray nozzles, with its four heaters turned on, chimney height of 0.645 m and 0.358 m3/s of gas. In conclusion, the design modification had increased the collection efficiency from about 70 %, in dry cyclones, to 97.07 %.