Wind patterns in the Pacific Ocean fluctuate seasonally, annually, and decadally, resulting in changes in the dispersal of volcanic smog (vog) across the Hawaiian Islands. A variety of synoptic-scale weather patterns can affect the Islands, creating variability in the direction and intensity of wind patterns. Recent changes in wind profiles were analyzed to identify possible patterns that could influence and increase the dispersion of vog over time on Hawai’i Island and the other Hawaiian Islands to the northwest. Historically, Northeast Trade Winds prevailed for much of the year, shifting vog into the Pacific Ocean southwest of Hawaii and away from the state’s principal population centers, but Northeast Trade Winds have shown a 20+% reduction over the past several decades. An increase in the southerly source of prevailing wind increased the frequency and intensity of vog and its impacts on the environment and health and well-being of people across the Islands.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-05-14T19:13:34Z No. of bitstreams: 1 NILZELE DE VILHENA GOMES JESUS – TESE (PPGMET) 2014.pdf: 6278341 bytes, checksum: d1799ad3cede1860eb4826792903ca83 (MD5) / Made available in DSpace on 2018-05-14T19:13:34Z (GMT). No. of bitstreams: 1 NILZELE DE VILHENA GOMES JESUS – TESE (PPGMET) 2014.pdf: 6278341 bytes, checksum: d1799ad3cede1860eb4826792903ca83 (MD5) Previous issue date: 2014-08-29 / Capes / A ocorrência de condições meteorológicas adversas em aeroportos determina situações desfavoráveis ao tráfego aéreo, como restrição de visibilidade e teto, além de condições de pista escorregadia, que constituem um fator de grande risco à segurança das operações. Estes contratempos podem acarretar prejuízos vultosos para as empresas envolvidas e desconforto ao usuário da aeronavegação. Por isso, este estudo teve como objetivo a determinação de padrões atmosféricos que originam a ocorrência de condições meteorológicas adversas no Aeroporto Internacional de Belém (SBBE), através da aplicação da análise fatorial (AF) em análises de componentes principais (ACP). Foram usados os dados meteorológicos de superfície do SBBE e de Radiação de Onda Longa (ROL), em ponto de grade sobre Belém, proveniente das reanálises do National Centers for Environmental Prediction (NCEP). Através dos indicadores estatísticos, foi selecionado o conjunto de variáveis adequadas para a aplicação daACP. Os dados utilizados foram dos períodos chuvosos de 2003 a 2012, pois na estação chuvosa foi detectado o maior número de emissões de mensagens especiais (código SPECI) no SBBE. O fator dominante está associado à variação diária do aquecimento/resfriamento da superfície. O segundo fator representa as alterações no teor de umidade próximo da superfície, decorrente da variabilidade climática associada com anomalias da temperatura da superfície do mar nos Oceanos Atlântico e Pacífico. E o outro fator igualmente importante, tem relação com a presença de convecção profunda, e consequentemente, de tempestades, as quais foram desenvolvidas por mecanismos das circulações locaisdinâmicos em mesoescala, tais como circulações de brisa marítima e/ou fluvial sobre a área em que se localiza o SBBE. Este último fator foi o qual apresentou o maior número de ocorrência das variáveis que apresentam relação com o estabelecimento das situações meteorológicas adversas que limitam as operações de pousos e decolagens no SBBE. / The occurrence of adverse weather conditions at airports determines unfavorable situations to air traffic, as visibility and ceiling restriction, and slippery track conditions, which are a major risk factor for safety operations. These setbacks can cause sizeable losses for the companies involved and discomfort to the airworthiness of the users. Therefore, this study aimed at determining weather patterns that cause the occurrence of adverse weather conditions in Belem International Airport (SBBE) through the application of factor analysis (FA) on principal components analysis (PCA). It wasused meteorological surface data from the SBBE and outgoing longwave radiation (OLR), in grid point over Belém (Brazil), from the reanalysis of the National Centers for Environmental Prediction (NCEP). Through statistical indicators, it was selected the appropriate set of variables for the application of the PCA. The data used were in the rainy periods of 2003 to 2012, as the rainy season has been detected as many reports of the SPECI code in the SBBE. The dominant factor is associated with the daily variation of the heating/cooling of the surface. The second factor is the changes in the moisture content near the surface as a result of climate variability associated with temperature anomalies of the sea surface in the Atlantic and Pacific Oceans. And another equally important factor is related to the presence of deep convection, and consequently storms, which were developed by mechanisms of dynamic local mesoscale circulations such as circulations of maritime and/or fluvial breeze over the area in which is located the SBBE. This last factor was the one which had the highest number of occurrences of the variables that have relation with the establishment of the adverse weather conditions that limit of takeoffs and landings operations in the SBBE.