Testing of the Tropically Excited Arctic Warming Mechanism (TEAM) with Traditional El Niño and La Niña

2012 ◽  
Vol 25 (12) ◽  
pp. 4015-4022 ◽  
Author(s):  
Sukyoung Lee
Keyword(s):  
Air Temperature ◽  
El Niño ◽  
Energy Transport ◽  
El Nino ◽  
Surface Air Temperature ◽  
La Niña ◽  
The Arctic ◽  
Convective Heating ◽  
Arctic Warming ◽  
La Nina

Abstract By analyzing El Niño and La Niña composites with 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) data, evidence is presented here that the surface air temperature of the Arctic winter (December–February) is anomalously warm during La Niña and cold during El Niño. Surface and top-of-the-atmosphere energy fluxes were used to calculate the composite zonal-mean poleward moist static energy transport. The result shows that the La Niña warming in the Arctic is associated with an increased poleward energy transport in the extratropics. The opposite characteristics are found for El Niño. Because the total tropical convective heating is more localized during La Niña than El Niño, these findings suggest that the Arctic surface air temperature anomalies associated with ENSO may be attributed to the tropically excited Arctic warming mechanism (TEAM). In the tropics, consistent with previous studies, the anomalous poleward energy transport is positive during El Niño and negative during La Niña. Given the debate over whether a warmer world would take on more El Niño–like or La Niña–like characteristics, the findings of this study underscore the need for further investigation of tropical influence on polar climate.

scholarly journals Percolation Phase Transition of Surface Air Temperature Networks: A new test bed for El Niño/La Niña simulations

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Lijuan Hua ◽  
Zhenghui Lu ◽  
Naiming Yuan ◽  
Lin Chen ◽  
Yongqiang Yu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Air Temperature ◽  
El Niño ◽  
El Nino ◽  
Surface Air Temperature ◽  
La Niña ◽  
Test Bed ◽  
La Nina

scholarly journals WAVELET ANALYSIS OF THE El NIÑO - LA NIÑA PHENOMENON DYNAMICS AND ITS FORECASTING

2018 ◽  
Vol 14 (3) ◽  
pp. 75-87
Author(s):  
V I Alekseev
Keyword(s):  
Air Temperature ◽  
El Niño ◽  
El Nino ◽  
Surface Air Temperature ◽  
La Niña ◽  
Frequency Content ◽  
Time Intervals ◽  
Instantaneous Phase ◽  
La Nina ◽  
Phase Differences

Having calculated the frequency content of a solar constant, solar activity from the time series in (1610-2012), the El Niño curve in both (1470-1984) and (1950-2075), it has been found that the frequency content of an El Niño - La Niña curve is induced by frequency contents of solar variables. The frequency contents of the variables have been calculated by developing their wavelet phase-frequency responses. Instantaneous phase differences of the solar variables curves CO2(t), global surface air temperature, El Niño in the two time intervals, in (1891-1950) and (1950-2009), have been calculated; linear approximations with coefficients of instantaneous phase differences between variables in these time intervals have been obtained. Based on relational approximation coefficient analysis of the two time intervals, it has been identified that rising surface air temperature and El Niño alike had been markedly influenced by solar variables variations during the first time interval, with the El Niño rise being affected by that of the surface air temperature amid the global climate change in 1950-2009. The predicted El Niño curves have been obtained from the 2015/16 to 2050 time period by the trained data curve in 1950-2015/16 in two versions as the sum of predicted wavelet approximating and detailing components of the original signal according to the Mallat rule. The accuracy of the predictive El Niño curve values is » 83%. On the obtained curves, coordinates of local maximum and minimum are nearly matching. Wavelet phase-frequency response imaging of one curve reflects an impact on El Niño - La Niña variations of the Earth's solar and climatic variables in the past and the future alike.

scholarly journals Network analysis reveals strongly localized impacts of El Niño

2017 ◽  
Vol 114 (29) ◽  
pp. 7543-7548 ◽  
Author(s):  
Jingfang Fan ◽  
Jun Meng ◽  
Yosef Ashkenazy ◽  
Shlomo Havlin ◽  
Hans Joachim Schellnhuber
Keyword(s):  
El Niño ◽  
El Nino ◽  
Large Fraction ◽  
Surface Air Temperature ◽  
Climatic Conditions ◽  
La Niña ◽  
Near Surface ◽  
La Nina ◽  
Agriculture Industry ◽  
Global Impacts

Climatic conditions influence the culture and economy of societies and the performance of economies. Specifically, El Niño as an extreme climate event is known to have notable effects on health, agriculture, industry, and conflict. Here, we construct directed and weighted climate networks based on near-surface air temperature to investigate the global impacts of El Niño and La Niña. We find that regions that are characterized by higher positive/negative network “in”-weighted links are exhibiting stronger correlations with the El Niño basin and are warmer/cooler during El Niño/La Niña periods. In contrast to non-El Niño periods, these stronger in-weighted activities are found to be concentrated in very localized areas, whereas a large fraction of the globe is not influenced by the events. The regions of localized activity vary from one El Niño (La Niña) event to another; still, some El Niño (La Niña) events are more similar to each other. We quantify this similarity using network community structure. The results and methodology reported here may be used to improve the understanding and prediction of El Niño/La Niña events and also may be applied in the investigation of other climate variables.

scholarly journals State of the Climate in 2010

2011 ◽  
Vol 92 (6) ◽  
pp. S1-S236 ◽  
Author(s):  
J. Blunden ◽  
D. S. Arndt ◽  
M. O. Baringer
Keyword(s):  
Carbon Dioxide ◽  
Sea Ice ◽  
North Atlantic ◽  
El Niño ◽  
Arctic Oscillation ◽  
El Nino ◽  
La Niña ◽  
The Arctic ◽  
La Nina ◽  
The Antarctic

Several large-scale climate patterns influenced climate conditions and weather patterns across the globe during 2010. The transition from a warm El Niño phase at the beginning of the year to a cool La Niña phase by July contributed to many notable events, ranging from record wetness across much of Australia to historically low Eastern Pacific basin and near-record high North Atlantic basin hurricane activity. The remaining five main hurricane basins experienced below- to well-below-normal tropical cyclone activity. The negative phase of the Arctic Oscillation was a major driver of Northern Hemisphere temperature patterns during 2009/10 winter and again in late 2010. It contributed to record snowfall and unusually low temperatures over much of northern Eurasia and parts of the United States, while bringing above-normal temperatures to the high northern latitudes. The February Arctic Oscillation Index value was the most negative since records began in 1950. The 2010 average global land and ocean surface temperature was among the two warmest years on record. The Arctic continued to warm at about twice the rate of lower latitudes. The eastern and tropical Pacific Ocean cooled about 1°C from 2009 to 2010, reflecting the transition from the 2009/10 El Niño to the 2010/11 La Niña. Ocean heat fluxes contributed to warm sea surface temperature anomalies in the North Atlantic and the tropical Indian and western Pacific Oceans. Global integrals of upper ocean heat content for the past several years have reached values consistently higher than for all prior times in the record, demonstrating the dominant role of the ocean in the Earth's energy budget. Deep and abyssal waters of Antarctic origin have also trended warmer on average since the early 1990s. Lower tropospheric temperatures typically lag ENSO surface fluctuations by two to four months, thus the 2010 temperature was dominated by the warm phase El Niño conditions that occurred during the latter half of 2009 and early 2010 and was second warmest on record. The stratosphere continued to be anomalously cool. Annual global precipitation over land areas was about five percent above normal. Precipitation over the ocean was drier than normal after a wet year in 2009. Overall, saltier (higher evaporation) regions of the ocean surface continue to be anomalously salty, and fresher (higher precipitation) regions continue to be anomalously fresh. This salinity pattern, which has held since at least 2004, suggests an increase in the hydrological cycle. Sea ice conditions in the Arctic were significantly different than those in the Antarctic during the year. The annual minimum ice extent in the Arctic—reached in September—was the third lowest on record since 1979. In the Antarctic, zonally averaged sea ice extent reached an all-time record maximum from mid-June through late August and again from mid-November through early December. Corresponding record positive Southern Hemisphere Annular Mode Indices influenced the Antarctic sea ice extents. Greenland glaciers lost more mass than any other year in the decade-long record. The Greenland Ice Sheet lost a record amount of mass, as the melt rate was the highest since at least 1958, and the area and duration of the melting was greater than any year since at least 1978. High summer air temperatures and a longer melt season also caused a continued increase in the rate of ice mass loss from small glaciers and ice caps in the Canadian Arctic. Coastal sites in Alaska show continuous permafrost warming and sites in Alaska, Canada, and Russia indicate more significant warming in relatively cold permafrost than in warm permafrost in the same geographical area. With regional differences, permafrost temperatures are now up to 2°C warmer than they were 20 to 30 years ago. Preliminary data indicate there is a high probability that 2010 will be the 20th consecutive year that alpine glaciers have lost mass. Atmospheric greenhouse gas concentrations continued to rise and ozone depleting substances continued to decrease. Carbon dioxide increased by 2.60 ppm in 2010, a rate above both the 2009 and the 1980–2010 average rates. The global ocean carbon dioxide uptake for the 2009 transition period from La Niña to El Niño conditions, the most recent period for which analyzed data are available, is estimated to be similar to the long-term average. The 2010 Antarctic ozone hole was among the lowest 20% compared with other years since 1990, a result of warmer-than-average temperatures in the Antarctic stratosphere during austral winter between mid-July and early September.

Quantifying the Non-Gaussianity of Wintertime Daily Maximum and Minimum Temperatures in the Southeast

2013 ◽  
Vol 26 (3) ◽  
pp. 838-850 ◽  
Author(s):  
Lydia Stefanova ◽  
Philip Sura ◽  
Melissa Griffin
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Surface Air Temperature ◽  
La Niña ◽  
Daily Maximum ◽  
Seasonal Temperature ◽  
Southeast United States ◽  
La Nina ◽  
Maximum Temperatures

Abstract In this paper the statistics of daily maximum and minimum surface air temperature at weather stations in the southeast United States are examined as a function of the El Niño–Southern Oscillation (ENSO) and Arctic Oscillation (AO) phase. A limited number of studies address how the ENSO and/or AO affect U.S. daily—as opposed to monthly or seasonal—temperature averages. The details of the effect of the ENSO or AO on the higher-order statistics for wintertime daily minimum and maximum temperatures have not been clearly documented. Quality-controlled daily observations collected from 1960 to 2009 from 272 National Weather Service Cooperative Observing Network stations throughout Florida, Georgia, Alabama, and South and North Carolina are used to calculate the first four statistical moments of minimum and maximum daily temperature distributions. It is found that, over the U.S. Southeast, winter minimum temperatures have higher variability than maximum temperatures and La Niña winters have greater variability of both minimum and maximum temperatures. With the exception of the Florida peninsula, minimum temperatures are positively skewed, while maximum temperatures are negatively skewed. Stations in peninsular Florida exhibit negative skewness for both maximum and minimum temperatures. During the relatively warmer winters associated with either a La Niña or AO+, negative skewnesses are exacerbated and positive skewnesses are reduced. To a lesser extent, the converse is true of the El Niño and AO−. The ENSO and AO are also shown to have a statistically significant effect on the change in kurtosis of daily maximum and minimum temperatures throughout the domain.

scholarly journals Can ENSO-Like Convection Force an ENSO-Like Extratropical Response on Subseasonal Time Scales?

2018 ◽  
Vol 31 (20) ◽  
pp. 8339-8349 ◽  
Author(s):  
Michael Goss ◽  
Sukyoung Lee ◽  
Steven B. Feldstein ◽  
Noah S. Diffenbaugh
Keyword(s):  
North America ◽  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
La Niña ◽  
Convective Heating ◽  
Western North America ◽  
The North ◽  
La Nina ◽  
The North Pacific

A daily El Niño–Southern Oscillation (ENSO) index is developed based on precipitation rate and is used to investigate subseasonal time-scale extratropical circulation anomalies associated with ENSO-like convective heating. The index, referred to as the El Niño precipitation index (ENPI), is anomalously positive when there is El Niño–like convection. Conversely, the ENPI is anomalously negative when there is La Niña–like convection. It is found that when precipitation becomes El Niño–like (La Niña–like) on subseasonal time scales, the 300-hPa geopotential height field over the North Pacific and western North America becomes El Niño–like (La Niña–like) within 5–10 days. The composites show a small association with the MJO. These results are supported by previous modeling studies, which show that the response over the North Pacific and western North America to an equatorial Pacific heating anomaly occurs within about one week. This suggests that the mean seasonal extratropical response to El Niño (La Niña) may in effect simply be the average of the subseasonal response to subseasonally varying El Niño–like (La Niña–like) convective heating. Implications for subseasonal to seasonal forecasting are discussed.

scholarly journals Climatologia Urbana da Cidade de Belém-Pará, através das Precipitações e Temperaturas do Ar, das Normais Climatológicas de 1941 a 1970, 1971 a 2000 e da Normal Provisória de 2001 a 2015 (Urban Climatology of the City of Belem-Pará-Brazil, throughout...)

2016 ◽  
Vol 9 (3) ◽  
pp. 803
Author(s):  
Maria do Carmo Felipe de Oliveira ◽  
José Augusto De Souza Júnior ◽  
Patrícia Porta Nova da Cruz ◽  
José Danilo Souza Filho
Keyword(s):  
Air Temperature ◽  
El Niño ◽  
El Nino ◽  
La Niña ◽  
Extreme Weather Events ◽  
Urban Climatology ◽  
Monthly Average ◽  
La Nina ◽  
Air Temperatures ◽  
Weather Events

Este trabalho teve como objetivo estudar a climatologia urbana de Belém-PA, tendo como base as precipitações e as temperaturas do ar, através da comparação entre as Normais Climatológicas de 1941-1970, 1971-2000 e a Normal Provisória de 2001-2015, buscando quantificar possíveis alterações climáticas e identificar a influência de eventos climáticos, de EL Niño e LA Niña, o que certamente contribuirá para um melhor planejamento urbano, visando na melhoria de qualidade de vida do homem. Foram utilizados os dados das precipitações e temperaturas do ar, fornecidos pelo Instituto Nacional de Meteorologia– INMET, e foram calculados parâmetros estatísticos e as anomalias anuais para identificar a variabilidade nos dados e a influência dos eventos extremos. Os resultados mostraram que, o regime médio mensal da precipitação pluviométrica e das temperaturas do ar, para as Normais, apresenta dois períodos distintos, um mais chuvoso e menos quente, de Janeiro a Maio e um menos chuvoso e mais quente, de Junho a Dezembro. Os totais médios mensais e anuais mostraram aumentos nas chuvas e nos valores de temperaturas do ar, quando comparados entre as Normais, porém, com alternância entre períodos de aumento gradual, com seqüência de queda. As anomalias mostraram a influência dos eventos climáticos extremos, na climatologia da região, tanto no regime pluviométrico, quanto no regime térmico, com redução e/ou aumento nos valores calculados, provocando secas severas e temperaturas mais elevadas, em anos de EL Niño e gerando grandes enchentes com transbordamento de rios e redução nos valores das temperaturas do ar em anos da La Niña.  A B S T R A C T This work aimed to study the urban climatology of Belém-Pará-Brazil, based on precipitation and air temperatures, by comparing the Climatological Standards of 1941-1970, 1971-2000 and provisional standard of 2001-2015, seeking quantify potential climate change and identify the influence of weather events, like El Niño and La Niña events, which will certainly contribute to a better urban planning in order to improve man's quality of life. Precipitation and air temperatures data were used in the research, provided by the National Institute of Meteorology (INMET), and were calculated statistical parameters and annual anomalies to identify the variability in the data and the influence of extreme events. The results showed that the monthly average pattern of rainfall and air temperatures, for the Climatological Standards, demonstrate two distinct periods, one rainier and less hot, from January to May and a less rainy and warmer, from June to December. Annual and monthly average totals demonstrated increases in rainfall and in air temperature values, when compared between the Standards, however, with alternating periods of gradual increase, with decrease sequence. Anomalies showed the influence of extreme weather events, in the climatology of the region, both in rainfall as thermal patterns, with reduction and/or increase in the calculated values, causing severe drought and higher air temperatures in years of El Niño and causing large floods with overflowing in rivers and reduced values ​​of air temperatures in the La Niña years. Keywords: Precipitation; Air temperature; Climatological Standard and provisional; Extreme climate events; Belém-Pará-Brazil.   

scholarly journals Asymmetry in the IOD and ENSO Teleconnection in a CMIP5 Model Ensemble and Its Relevance to Regional Rainfall

2013 ◽  
Vol 26 (14) ◽  
pp. 5139-5149 ◽  
Author(s):  
Evan Weller ◽  
Wenju Cai
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
Climate Models ◽  
El Nino ◽  
La Niña ◽  
Convective Heating ◽  
La Nina ◽  
The Pacific ◽  
Australian Climate ◽  
The Impact

Abstract Recent studies have shown that the impact of the Indian Ocean dipole (IOD) on southern Australia occurs via equivalent barotropic Rossby wave trains triggered by convective heating in the tropical Indian Ocean. Furthermore, the El Niño–Southern Oscillation (ENSO) influence on southern Australian climate is exerted through the same pathway during austral spring. It is also noted that positive phase [positive IOD (pIOD) and El Niño] events have a much larger impact associated with their respective skewness. These phenomena play a significant role in the region's rainfall reduction in recent decades, and it is essential that climate models used for future projections simulate these features. Here, the authors demonstrate that climate models do indeed simulate a greater climatic impact on Australia for pIOD events than for negative IOD (nIOD) events, but this asymmetric impact is distorted by an exaggerated influence of La Niña emanating from the Pacific. The distortion results from biases in the Pacific in two respects. First, the tropical and extratropical response to La Niña is situated unrealistically too far westward and hence too close to Australia, leading to an overly strong impact on southeast Australia that shows up through the nIOD–La Niña coherence. Second, the majority of models simulate a positive sea surface temperature skewness in the eastern Pacific that is too weak, overestimating the impact of La Niña relative to that of El Niño. As such, the impact of the positive asymmetry in the IOD only becomes apparent when the impact of ENSO is removed. This model bias needs to be taken into account when analyzing projections of regional Australian climate change.

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