Effects of Atlantic multidecadal oscillation and Pacific decadal oscillation on interdecadal variability of fog frequency in autumn–winter season in Southwest China

2021 ◽  
Author(s):  
Peng Liu ◽  
Ying Zhang ◽  
Mingyue Tang
Keyword(s):  
Pacific Decadal Oscillation ◽  
Southwest China ◽  
Winter Season ◽  
Atlantic Multidecadal Oscillation ◽  
Interdecadal Variability

scholarly journals Stable isotope investigation of groundwater recharge in the Carpathian Mountains, East-Central Europe

2018 ◽  
Author(s):  
Carmen-Andreea Bădăluță ◽  
Aurel Perșoiu ◽  
Monica Ionita ◽  
Viorica Nagavciuc ◽  
Petruț-Ionel Bistricean
Keyword(s):  
Atmospheric Circulation ◽  
Large Scale ◽  
Precipitation Amount ◽  
Winter Season ◽  
Atlantic Multidecadal Oscillation ◽  
The Arctic ◽  
Altitude Effect ◽  
Mountain Area ◽  
The North ◽  
Large Scale Atmospheric Circulation

Abstract. Rapid growth in water usage in NW Romania has led to an increased pressure on the available water resources; however, the relationships between precipitation, surface and groundwater in the region are poorly understood. Here, we have analyzed the stable isotopes of oxygen and hydrogen in precipitation, river and groundwater to gain information on moisture sources feeding precipitation in the area and establish the main links between the large-scale atmospheric circulation, precipitation amount and discharge. Thus, in this study we have analyzed 157 groundwater samples, 64 precipitation samples from two collection sites (one in mountain area and another one in plateau area) and 54 rivers samples from two rivers. Furthermore, we have directly linked the changes in the isotopic composition of the d-excess parameter in the precipitation with the processes linked to large-scale atmospheric circulation. Isotopes in precipitation water resulted in two LMWLs (δ2H = 7.4*δ18O + 2.7 at 350 m asl and δ2H = 8.1*δ18O + 12.4 at 1530 m asl), with a clear seasonal signal, further enhanced by secondary evaporative processes in summer. Moisture in the lowlands was mostly delivered along easterly trajectories, while that in the mountain area from the westerlies. Surface water analyses show the same trend as precipitation, but with reduced amplitude between summer and winter values. Throughout the winter season, the δprec is strongly related with different climate teleconnection patterns like the East Atlantic (EA), the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO), while during summer, the δprec shows a strong correlation with the Atlantic Multidecadal Oscillation (AMO) and the summer EA. Maps of δ18O and d-excess distribution in groundwaters show a depletive trend from NW to SE, generated in principal by topography. The waters in the aquifers show no clear patterns and altitude effect.

scholarly journals Global-scale interdecadal variability a skillful predictor at decadal-to-multidecadal timescales for Sahelian and Indian Monsoon Rainfall

2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Manish K. Joshi ◽  
Archana Rai ◽  
Ashwini Kulkarni
Keyword(s):  
Climate Models ◽  
Physical Mechanism ◽  
Coupled Model ◽  
Walker Circulation ◽  
Atlantic Multidecadal Oscillation ◽  
Global Scale ◽  
Substantial Improvement ◽  
Interdecadal Variability ◽  
The Pacific ◽  
Temporal Variance

AbstractIn the present study, a sea surface temperature-based index named global-scale interdecadal variability (GIV) encompassing the combined variability of Atlantic multidecadal oscillation (AMO) and interdecadal Pacific oscillation (IPO) has been proposed. The warm phase of GIV exhibits a “cold AMO-like” pattern in the Atlantic basin and a “warm IPO-like” pattern in the Pacific basin. About 84% (R ~−0.914) of Sahelian and 42% (R ~−0.647) of Indian rainfall’s temporal variance is attributed to GIV, showing substantial improvement compared to the variance explained by AMO and IPO individually. The physical mechanism for GIV-rainfall teleconnection is related to a modification of the Walker circulation. Although there is a substantial degree of uncertainty in the current generation of state-of-the-art climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5), some still replicate the observed GIV’s spatial structure, its teleconnection, and associated physical mechanism. The results presented herein advance our knowledge about rainfall’s interdecadal variability and have imperative ramifications for developing skillful decadal predictions.

scholarly journals Análise da Relação entre a Precipitação Média do Reservatório Orós, Brasil - Ceará, e os índices PDO e AMO Através da Análise de Changepoints e Transformada de Ondeletas

2019 ◽  
Vol 34 (1) ◽  
pp. 139-149 ◽  
Author(s):  
Renan Vieira Rocha ◽  
Francisco de Assis de Souza Filho ◽  
Samiria Maria Oliveira da Silva
Keyword(s):  
Pacific Decadal Oscillation ◽  
Atlantic Multidecadal Oscillation

Resumo Os riscos de extremos hidrológicos para um local ou região estão associados aos modos de variação do clima, em suas diversas escalas temporais. A compreensão da variabilidade de baixa frequência ganha uma elevada importância em regiões onde eventos de seca são frequentes, por estar associada a longos períodos de secas consecutivas. O presente artigo analisou a relação entre a precipitação média da bacia a montante da estação fluviométrica de Iguatu, com os índices PDO e AMO (Pacific Decadal Oscillation e Atlantic Multidecadal Oscillation) através das metodologias de Análise de changepoint, Transformada de Ondeletas (TO), Transformada de Ondeletas Cruzadas (XTC) e Análise da Coerência das Ondeletas (WTC). Essa estação mensura as vazões afluente ao reservatório de Orós, um dos principais do Estado do Ceará (Brasil). A precipitação média da bacia foi obtida a partir de dados de pluviômetros. Os resultados permitiram estabelecer uma relação entre a precipitação da região e os índices PDO e AMO, indicando que um modelo baseado nos índices pode ter alguma capacidade preditiva do comportamento da precipitação local. Nota-se também que períodos com fases simultaneamente positivas (negativas) da PDO e da AMO resultam em um comportamento mais previsível das precipitações da região, com valores abaixo (acima) do normalmente esperado.

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