scholarly journals Seasonal Forecasting in the Pacific Using the Coupled Model POAMA-2

2013 ◽  
Vol 28 (3) ◽  
pp. 668-680 ◽  
Author(s):  
Andrew Cottrill ◽  
Harry H. Hendon ◽  
Eun-Pa Lim ◽  
Sally Langford ◽  
Kay Shelton ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Regional Climate ◽  
Coupled Model ◽  
Forecast Model ◽  
Seasonal Prediction ◽  
La Niña ◽  
Spatial And Temporal Variability ◽  
Seasonal Forecasts ◽  
La Nina

Abstract The development of a dynamical model seasonal prediction service for island nations in the tropical South Pacific is described. The forecast model is the Australian Bureau of Meteorology's Predictive Ocean–Atmosphere Model for Australia (POAMA), a dynamical seasonal forecast system. Using a hindcast set for the period 1982–2006, POAMA is shown to provide skillful forecasts of El Niño and La Niña many months in advance and, because the model faithfully simulates the spatial and temporal variability of rainfall associated with displacements of the southern Pacific convergence zone (SPCZ) and ITCZ during La Niña and El Niño, it also provides good predictions of rainfall throughout the tropical Pacific region. The availability of seasonal forecasts from POAMA should be beneficial to Pacific island countries for the production of regional climate outlooks across the region.

scholarly journals Predictability of the California Niño/Niña*

2015 ◽  
Vol 28 (18) ◽  
pp. 7237-7249 ◽  
Author(s):  
Takeshi Doi ◽  
Chaoxia Yuan ◽  
Swadhin K. Behera ◽  
Toshio Yamagata
Keyword(s):  
El Niño ◽  
General Circulation ◽  
El Nino ◽  
Regional Climate ◽  
Circulation Model ◽  
Seasonal Prediction ◽  
La Niña ◽  
Boreal Summer ◽  
La Nina ◽  
Basin Scale

Abstract Predictability of a recently discovered regional coupled climate mode called the California Niño (Niña) off Baja California and California is explored using a seasonal prediction system based on the Scale Interaction Experiment-Frontier, version 1 (SINTEX-F1) coupled ocean–atmosphere general circulation model. Because of the skillful prediction of basin-scale El Niño (La Niña), the California Niño (Niña) that co-occurs with El Niño (La Niña) with a peak in boreal winter is found to be predictable at least a couple of seasons ahead. On the other hand, the regional coupled phenomenon peaking in boreal summer without co-occurrence with El Niño (La Niña) is difficult to predict. The difficulty in predicting such an intrinsic regional climate phenomenon may be due to model deficiency in resolving the regional air–sea–land positive feedback processes. The model may also underestimate coastal Kelvin waves with a small offshore scale, which may play an important role in the generation of the California Niño/Niña. It may be improved by increasing horizontal resolution of the ocean component of the coupled model. The present study may provide a guideline to improve seasonal prediction of regional climate modes for important industrial as well as social applications.

Model Biases in the Simulation of the Springtime North Pacific ENSO Teleconnection

2020 ◽  
Vol 33 (23) ◽  
pp. 9985-10002
Author(s):  
Ruyan Chen ◽  
Isla R. Simpson ◽  
Clara Deser ◽  
Bin Wang
Keyword(s):  
El Niño ◽  
North Pacific ◽  
Climate Models ◽  
El Nino ◽  
Coupled Model ◽  
La Niña ◽  
Late Winter ◽  
The North ◽  
La Nina ◽  
The North Pacific

AbstractThe wintertime ENSO teleconnection over the North Pacific region consists of an intensified (weakened) low pressure center during El Niño (La Niña) events both in observations and in climate models. Here, it is demonstrated that this teleconnection persists too strongly into late winter and spring in the Community Earth System Model (CESM). This discrepancy arises in both fully coupled and atmosphere-only configurations, when observed SSTs are specified, and is shown to be robust when accounting for the sampling uncertainty due to internal variability. Furthermore, a similar problem is found in many other models from piControl simulations of the Coupled Model Intercomparison Project (23 out of 43 in phase 5 and 11 out of 20 in phase 6). The implications of this bias for the simulation of surface climate anomalies over North America are assessed. The overall effect on the ENSO composite field (El Niño minus La Niña) resembles an overly prolonged influence of ENSO into the spring with anomalously high temperatures over Alaska and western Canada, and wet (dry) biases over California (southwest Canada). Further studies are still needed to disentangle the relative roles played by diabatic heating, background flow, and other possible contributions in determining the overly strong springtime ENSO teleconnection intensity over the North Pacific.

scholarly journals A Bayesian Regression Approach to Seasonal Prediction of Tropical Cyclones Affecting the Fiji Region

2010 ◽  
Vol 23 (13) ◽  
pp. 3425-3445 ◽  
Author(s):  
Savin S. Chand ◽  
Kevin J. E. Walsh ◽  
Johnny C. L. Chan
Keyword(s):  
Tropical Cyclones ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Seasonal Prediction ◽  
Bayesian Regression ◽  
La Niña ◽  
Annual Number ◽  
La Nina ◽  
Neutral Conditions

Abstract This study presents seasonal prediction schemes for tropical cyclones (TCs) affecting the Fiji, Samoa, and Tonga (FST) region. Two separate Bayesian regression models are developed: (i) for cyclones forming within the FST region (FORM) and (ii) for cyclones entering the FST region (ENT). Predictors examined include various El Niño–Southern Oscillation (ENSO) indices and large-scale environmental parameters. Only those predictors that showed significant correlations with FORM and ENT are retained. Significant preseason correlations are found as early as May–July (approximately three months in advance). Therefore, May–July predictors are used to make initial predictions, and updated predictions are issued later using October–December early-cyclone-season predictors. A number of predictor combinations are evaluated through a cross-validation technique. Results suggest that a model based on relative vorticity and the Niño-4 index is optimal to predict the annual number of TCs associated with FORM, as it has the smallest RMSE associated with its hindcasts (RMSE = 1.63). Similarly, the all-parameter-combined model, which includes the Niño-4 index and some large-scale environmental fields over the East China Sea, appears appropriate to predict the annual number of TCs associated with ENT (RMSE = 0.98). While the all-parameter-combined ENT model appears to have good skill over all years, the May–July prediction of the annual number of TCs associated with FORM has two limitations. First, it underestimates (overestimates) the formation for years where the onset of El Niño (La Niña) events is after the May–July preseason or where a previous La Niña (El Niño) event continued through May–July during its decay phase. Second, its performance in neutral conditions is quite variable. Overall, no significant skill can be achieved for neutral conditions even after an October–December update. This is contrary to the performance during El Niño or La Niña events, where model performance is improved substantially after an October–December early-cyclone-season update.

scholarly journals Representation of Boreal Winter MJO and Its Teleconnection in a Dynamical Ensemble Seasonal Prediction System

2018 ◽  
Vol 31 (21) ◽  
pp. 8803-8818 ◽  
Author(s):  
Hyerim Kim ◽  
Myong-In Lee ◽  
Daehyun Kim ◽  
Hyun-Suk Kang ◽  
Yu-Kyung Hyun
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Seasonal Prediction ◽  
La Niña ◽  
Prediction Skill ◽  
Boreal Winter ◽  
Teleconnection Patterns ◽  
La Nina ◽  
Forecast Lead Time

This study examines the representation of the Madden–Julian oscillation (MJO) and its teleconnection in boreal winter in the Global Seasonal Forecast System, version 5 (GloSea5), using 20 years (1991–2010) of hindcast data. The sensitivity of the performance to the polarity of El Niño–Southern Oscillation (ENSO) is also investigated. The real-time multivariate MJO index of Wheeler and Hendon is used to assess MJO prediction skill while intraseasonal 200-hPa streamfunction anomalies are used to evaluate the MJO teleconnection. GloSea5 exhibits significant MJO prediction skill up to 25 days of forecast lead time. MJO prediction skill in GloSea5 also depends on initial MJO phases, with relatively enhanced (degraded) performance when the initial MJO phase is 2 or 3 (8 or 1) during the first 2 weeks of the hindcast period. GloSea5 depicts the observed MJO teleconnection patterns in the extratropics realistically up to 2 weeks albeit weaker than the observed. The ENSO-associated basic-state changes in the tropics and in the midlatitudes are reasonably represented in GloSea5. MJO prediction skill during the first 2 weeks of the hindcast is slightly higher in neutral and La Niña years than in El Niño years, especially in the upper-level zonal wind anomalies. Presumably because of the better representation of MJO-related tropical heating anomalies, the Northern Hemispheric MJO teleconnection patterns in neutral and La Niña years are considerably better than those in El Niño years.

scholarly journals Visualizing the Large-Scale Patterns of ENSO-Related Climate Anomalies in North America

2009 ◽  
Vol 13 (3) ◽  
pp. 1-50 ◽  
Author(s):  
Jacqueline J. Shinker ◽  
Patrick J. Bartlein
Keyword(s):  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Precipitation Anomaly ◽  
La Niña ◽  
Specific Humidity ◽  
Spatial And Temporal Variability ◽  
Climate Anomalies ◽  
Enso Events ◽  
La Nina

Abstract The variations of large-scale climatic controls and surface responses through the annual cycle during strong positive (El Niño) and negative (La Niña) phase ENSO events are analyzed to assess the within-year and among-year variations of climate anomalies. Data from the NCEP–NCAR reanalysis project are presented as small-multiple maps to illustrate the spatial and temporal variability in North American climate associated with extreme phases of ENSO. Temperature, mean sea level pressure, 500-mb geopotential heights, and 850-mb specific humidity have composite-anomaly patterns that exhibit the greatest degree of spatial and temporal coherence. In general, the composite-anomaly patterns for El Niño and La Niña events are of opposite sign, with stronger, more spatially coherent anomalies occurring during El Niño events than during La Niña events. However, the strength and coherency of the precipitation anomaly patterns are reduced in the interior intermountain west during both positive and negative phase of ENSO. The variations in precipitation anomalies are compared to the 500-mb omega and 850-mb specific humidity composite-anomaly patterns, which provide information on the controls of precipitation by large-scale vertical motions and moisture availability thus providing information on the specific mechanisms associated with precipitation variability during ENSO events.

scholarly journals Veranicos no Brasil: Observações e Modelagens (CMIP5)

2019 ◽  
Vol 34 (4) ◽  
pp. 597-626 ◽  
Author(s):  
Anderson J. da Silva Magalhães ◽  
José Maria Brabo Alves ◽  
Emerson Mariano da Silva ◽  
Flávio Teixeira Nunes ◽  
Augusto César B. Barbosa ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Coupled Model ◽  
Climate Prediction ◽  
La Niña ◽  
La Nina ◽  
Climate Prediction Center

Resumo Na América do Sul, a oferta de água em diversas regiões, é uma condição limitante ao desenvolvimento socioeconômico. Observam-se impactos mais constantes nas áreas sociais e econômicas devido à estiagem, por exemplo, no Nordeste do Brasil (NEB) e Centro Oeste do Brasil (COB), principalmente em atividades como a agricultura, criação de animais, distribuição de energia elétrica e abastecimento de água e turismo. O objetivo deste trabalho foi investigar quantitativamente e qualitativamente as características de veranicos de cindo e dez dias no Brasil durante duas estações austrais e a relação destes eventos de seca em anos de contrastes climáticos como de El Niño, La Niña no Pacífico Tropical para o período de 1971-1999 e período futuro (2021-2050), com o intuito de aprimorar o conhecimento da variação sazonal das precipitações no país, com ênfase nos veranicos para potencializar ações socioeconômicas que dependam de suas variabilidades com menos riscos. Foram usados dados de precipitação diária (1971-1999) do banco de dados do National Center Environment Prediction-Climate Prediction Center-NCEP-CPC da National Ocean and Atmospheric Admistration - NOAA dos Estados Unidos sobre o Brasil, disponíveis em pontos de grade (1° x 1° de latitude e longitude). Para as comparações com esses dados observados e para os períodos futuros foram usados dados diários de precipitação simulados do projeto CMIP5 (Coupled Model lIntercomparison Project 5th Phase), de modelos nos períodos 1971-1999 e projetados para o período de 2021 a 2050, com configurações do experimento RCP8.5 para analisar a variabilidade atual observada de veranicos no Brasil e suas projeções futuras. Os resultados mostraram que para o período de 2021-2050 comparado as observações de 1971-1999, os modelos do CMIP5 projetaram uma maior probabilidade de mais eventos de veranicos de dez dias no COB e mais eventos menor ou igual cinco dias sobre o NEB para as estações de verão e outono.

Rain-on-Snow Events in the Western United States

2007 ◽  
Vol 88 (3) ◽  
pp. 319-328 ◽  
Author(s):  
Gregory J. McCabe ◽  
Martyn P. Clark ◽  
Lauren E. Hay
Keyword(s):  
United States ◽  
El Niño ◽  
Temporal Variability ◽  
El Nino ◽  
Flood Hazard ◽  
La Niña ◽  
Western United States ◽  
Spatial And Temporal Variability ◽  
Southwestern United States ◽  
La Nina

Rain-on-snow events pose a significant flood hazard in the western United States. This study provides a description of the spatial and temporal variability of the frequency of rain-on-snow events for 4318 sites in the western United States during water years (October through September) 1949–2003. Rain-on-snow events are found to be most common during the months of October through May; however, at sites in the interior western United States, rain-on-snow events can occur in substantial numbers as late as June and as early as September. An examination of the temporal variability of October through May rain-on-snow events indicates a mixture of increasing and decreasing trends in rain-on-snow events across the western United States. Decreasing trends in rain-on-snow events are most pronounced at lower elevations and are associated with trends toward fewer snowfall days and fewer precipitation days with snow on the ground. Rain-on-snow events are more (less) frequent in the northwestern (southwestern) United States during La Niña (El Niño) conditions. Additionally, increases in temperature in the western United States appear to be contributing to decreases in the number of rain-on-snow events for many sites through effects on the number of days with snowfall and the number of days with snow on the ground.

scholarly journals Sensitivity of RegCM3 Simulated Precipitation over Southern Brazil with Different Boundary Conditions: ENSO Case

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Simone Erotildes Teleginski Ferraz ◽  
Diego Pedroso
Keyword(s):  
Boundary Conditions ◽  
El Niño ◽  
Climate Model ◽  
El Nino ◽  
Regional Climate ◽  
La Niña ◽  
Southern Brazil ◽  
Different Boundary Conditions ◽  
La Nina ◽  
Simulated Precipitation

This paper investigates the capability of a regional climate model (RegCM3) to simulate the Southern Brazil rainfall during three periods: the El Niño (1982), the neutral intermediary phase (1985), and the La Niña (1988). Each integration has used three of different boundary conditions available: NCEP-NCAR Reanalysis (I and II) and ECMWF Reanalysis—ERA-40. The simulations were performed covering a South America domain and some descriptive statistics analyses have been applied, like arithmetic mean, median, standard deviation and Pearson’s correlation; and frequencies histogram over Southern Brazil. The main results show that the model satisfactorily reproduces the rainfall in this region during the El Niño, neutral, and La Niña events, indicating that the boundary conditions which were tested adequately describe this simulations type.

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