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

Désalmand, Françoise

doi:10.4267/2042/54533

Cited by 50 publications

(71 citation statements)

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“…Along the west coast of North America (NA), high-impact ARs often arrive in the cold season when weather is dominated by the strong onshore flow of Pacific airstreams 2,9,[11][12][13][14] . Some of these systems are also known as pineapple express storms for their apparent origin in the tropical area near Hawaii [15][16][17] . Their landfall on mountainous areas can produce extremely heavy precipitation and may trigger hazardous floods, mudslides, and avalanches.…”

mentioning

confidence: 99%

An anomalous warm-season trans-Pacific atmospheric river linked to the 2021 western North America heatwave

Lin

2022

Commun Earth Environ

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Atmospheric rivers are long and narrow bands of enhanced water vapour transport concentrated in the lower troposphere. Many studies have documented the important role of cold-season atmospheric rivers in producing heavy precipitation and extreme flooding events. Relatively little research has been conducted on the warm-season atmospheric rivers and their impacts on heatwave events. Here we show an anomalous warm-season atmospheric river moving across the North Pacific and its interaction with the extreme western North American heatwave in late June 2021. This system transported moisture and heat energy from Southeast Asia to the northeast Pacific. Its landfall over Southeast Alaska resulted in substantial spillover of moisture and sensible heat beyond the Pacific Coast Ranges. We provide evidence indicating that the sensible heat flux convergence and the short-lived greenhouse effect of the trapped moisture could form a positive feedback mechanism leading to the northward expansion of the heatwave event across western Canada.

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mentioning

confidence: 99%

An anomalous warm-season trans-Pacific atmospheric river linked to the 2021 western North America heatwave

Lin

2022

Commun Earth Environ

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“…Às 0000 UTC do dia 27, ambos WRF e ERA-5 mostram a convergência dos vetores de vento em 850 hPa no norte do Estado do Paraná, o que é mais um indicativo da posição da frente fria. Além disso, a norte e a sul da região de convergência predominam massas ar quente e fria, respectivamente, o que destaca o contraste térmico que é um dos principais mecanismos de gênese dos ciclones (Ahrens & Henson, 2021). Às 1200 UTC já há ventos de quadrante sul sobre o sul de São Paulo, indicando que a frente já está nesse setor.…”

Section: Campos Sinóticosunclassified

“…A passagem desses sistemas sobre o Brasil geralmente está associada à configuração de ciclones extratropicais na costa sul-americana. A formação de ciclones, de acordo com Reboita e Marafon (2021), são mais frequentes no inverno austral, tendo como principais mecanismos de gênese os contrastes de temperatura do ar e a presença de correntes de jato em altos níveis da atmosfera (Ahrens & Henson, 2021). Já Silva et al (2014), ao elaborarem uma climatologia de frentes frias no sul de Minas Gerais sem diferenciar os tipos de frentes, obtiveram que as frentes frias são responsáveis por 56% do total da precipitação na primavera, enquanto a contribuição decresce para 27% durante o verão.…”

Section: Introductionunclassified

Avaliação do modelo Weather Research and Forecasting (WRF) na simulação operacional de um evento de frente fria no sudeste do Brasil

Araújo

Garcia

Monteiro

et al. 2023

Rev. Bras. Geog. Fis.

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A região sudeste do Brasil é afetada o ano todo por sistemas transientes como as frentes frias. A incursão de sistemas frontais, além de afetar o dia a dia da população, pode causar danos e prejuízos a diversos setores da sociedade. Um modelo que é utilizado operacionalmente para a previsão de tempo no sul de Minas Gerais desde 2014 no Centro de Estudos de Previsão de Tempo e Clima de Minas Gerais (CEPreMG) da Universidade Federal de Itajubá é o Weather Research and Forecast (WRF). Em 2019, em decorrência da disponibilidade de dados do Global Forecast System (GFS) com maior resolução horizontal para a geração das condições iniciais e de fronteira necessárias como entrada ao modelo e do aumento da capacidade computacional disponível para as simulações, foram implementadas alterações no sistema em operação no CEPreMG. Assim, este estudo objetiva avaliar o desempenho do WRF na simulação de um sistema frontal que atuou no sudeste do Brasil em agosto de 2021. De forma geral, o modelo WRF simulou corretamente a posição e tempo de atuação do sistema, mas com algumas diferenças na intensidade. Isso não representa propriamente um problema uma vez que a resolução do WRF e dos dados usados na validação são diferentes. Evaluation of the Weather Research and Forecasting (WRF) model in the operational simulation of a cold weather event in southeastern Brazil A B S T R A C TThe southeastern region of Brazil is affected throughout the year by transient systems such as cold fronts. The incursion of frontal systems, in addition to affecting the daily life of the population, can cause damage and losses to various sectors of the society. A model that has been operationally used for weather forecasting in the southern region of Minas Gerais since 2014 at the Minas Gerais Weather and Climate Forecast Studies Center (CEPreMG) at the Federal University of Itajubá is the Weather Research and Forecast (WRF). In 2019, due to the availability of higher horizontal resolution data from the Global Forecast System (GFS) to generate the initial and boundary conditions necessary as inputs to the model and due to the increase in the computational capacity available, changes were implemented in the operational forecast system at CEPreMG. Thus, this study aims to evaluate the performance of the WRF in the simulation of a frontal system that was registered in the southeastern of Brazil in August 2021. In general, WRF model correctly simulated the position and evolution of the system, but with some differences regarding the intensity. This is not really a problem since the resolution of the WRF and the data used in the validation are different.

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“…Proses ini berlanjut untuk tumbuh dan bertabrakan dengan tetesan cairan dingin. Ketika es mulai jatuh ke permukaan bumi, es tersebut tidak langsung mencair sebagai hujan [1]. Gerakan vertikal ini terjadi karena adanya vertical velocity, khususnya upward vertical velocity, dimana dapat meningkatkan perkembangan awan konvektif, dimana secara potensial menyebabkan cuaca buruk [13], contohnya kejadian hujan es [10] dan dapat mengganggu kondisi cuaca [5].…”

Section: Pendahulununclassified

Kajian Analisis Parameter Vertical Velocity dan Kaitannya dengan Kondisi Parameter Cuaca saat Kejadian Hujan ES

Ayasha¹

2022

BGB

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Hujan es terjadi di Sukabumi, Sekadau dan Bogor, yang terjadi masing–masing pada tanggal 23 Agustus 2020, 22 Agustus 2020 dan 23 September 2020. Fenomena cuaca ekstrem di tiga tempat ini terjadi di musim kemarau. Penelitian ini memanfaatkan data model reanalysis ERA5 untuk menganalisa kondisi vertical velocity saat terjadi hujan es dan kaitannya dengan parameter cuaca lain seperti kelembapan udara dan pola angin. Selain itu, data satelit produk HCAI (High resolution Cloud Analysis Information) digunakan sebagai data pendukung untuk analisis perkembangan awan konvektif. Berdasarkan hasil model ERA5, nilai vertical velocity di lapisan 925 mb s/d 300 mb untuk wilayah Sukabumi, Sekadau dan Bogor masing–masing berkisar antara –1.2–(–0.2), –1.5–(–0.2), –1–0 Pa/s. Nilai negatif sebelum kejadian hujan es mengindikasikan terdapat upward motion dari massa udara yang memicu pertumbuhan awan konvektif yang memproduksi hujan es. Selain itu, kelembapan udara di lapisan 850–700 mb terdeteksi basah dan berkisar antara 80–90%. Sementara itu, pola angin di ketiga wilayah tersebut menunjukan adanya konvergensi dengan perlambatan kecepatan angin berkisar antara 2–4 knots. Hasil tersebut menunjukan bahwa upward motion dari vertical velocity cukup untuk membentuk kelembapan udara yang basah di atmosfer dan konvergensi untuk pertumbuhan awan konvektif yang menghasilkan hujan es di musim kemarau.

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

Cited by 50 publications

References 0 publications

An anomalous warm-season trans-Pacific atmospheric river linked to the 2021 western North America heatwave

An anomalous warm-season trans-Pacific atmospheric river linked to the 2021 western North America heatwave

Avaliação do modelo Weather Research and Forecasting (WRF) na simulação operacional de um evento de frente fria no sudeste do Brasil

Kajian Analisis Parameter Vertical Velocity dan Kaitannya dengan Kondisi Parameter Cuaca saat Kejadian Hujan ES

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