Spatio-temporal variability of lightning and convective activity over South/South-East Asia with an emphasis during El Niño and La Niña

2017 ◽  
Vol 197 ◽  
pp. 150-166 ◽  
Author(s):  
Upal Saha ◽  
Devendraa Siingh ◽  
S.K. Midya ◽  
R.P. Singh ◽  
A.K. Singh ◽  
...  
Keyword(s):  
East Asia ◽  
El Niño ◽  
Temporal Variability ◽  
El Nino ◽  
La Niña ◽  
South East Asia ◽  
Convective Activity ◽  
La Nina ◽  
Spatio Temporal

scholarly journals El Niño–Southern Oscillation (ENSO) effect on interannual variability in spring aerosols over East Asia

2021 ◽  
Vol 21 (8) ◽  
pp. 5919-5933
Author(s):  
Anbao Zhu ◽  
Haiming Xu ◽  
Jiechun Deng ◽  
Jing Ma ◽  
Shuhui Li
Keyword(s):  
East Asia ◽  
Interannual Variability ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
La Niña ◽  
Carbonaceous Aerosol ◽  
El Nino Southern Oscillation ◽  
South East Asia ◽  
La Nina

Abstract. Effects of the El Niño–Southern Oscillation (ENSO) on the interannual variability in spring aerosols over East Asia are investigated using the Modern Era Retrospective analysis for Research and Applications Version 2 (MERRA-2) reanalysis aerosol data. Results show that the ENSO has a crucial effect on the spring aerosols over mainland South East Asia, southern China, and the ocean south of Japan. The above-normal (below-normal) aerosols are found over these regions during the ensuing spring of El Niño (La Niña). In contrast to the local aerosol diffusion in winter, the ENSO affects East Asian aerosols in the following spring mainly via the modulation of upstream aerosol generation and transport processes. The underlying physical mechanism is that during the ensuing spring of El Niño (La Niña), the dry (wet) air and reduced (enhanced) precipitation are beneficial for the increase (reduction) in biomass burning activities over northern mainland South East Asia, resulting in more (fewer) carbonaceous aerosol emissions. On the other hand, the anomalous anticyclone (cyclone) over the north-western Pacific (WNP) associated with El Niño (La Niña) enhances (weakens) the low-level south-westerly wind from northern mainland South East Asia to southern Japan, which transports more (less) carbonaceous aerosol downstream. Anomalous precipitation plays a role in reducing aerosols over the source region, but its washout effect over the downstream region is limited. The ENSO's impact on the ensuing spring aerosols is mainly attributed to the eastern Pacific ENSO rather than the central Pacific ENSO.

scholarly journals The Effects of El Niño-South Oscillation on the Winter Haze Pollution of China

2017 ◽  
Author(s):  
Shuyun Zhao ◽  
Hua Zhang ◽  
Bing Xie
Keyword(s):  
East Asia ◽  
El Niño ◽  
El Nino ◽  
Southern China ◽  
Eastern China ◽  
La Niña ◽  
Anthropogenic Aerosols ◽  
La Nina ◽  
Haze Pollution ◽  
Haze Days

Abstract. It is reported in previous studies that El Niño-South Oscillation (ENSO) influences not only the summer monsoon, but also the winter monsoon over East Asia. This contains some clues that ENSO may affect the winter haze pollution of China, which has become a serious problem in recent decades, through influencing the winter climate of East Asia. In this work, we explore the effects of ENSO on the winter (from December to February) haze pollution of China statistically and numerically. Statistical results reveal that the haze days of southern China tend to be less (more) than normal in El Niño (La Niña) winter; whereas the winter haze days of northern and eastern China have no significant relationship with ENSO. Results from numerical simulations show that under the emission level of aerosols for the year 2010, the winter-average atmospheric contents of anthropogenic aerosols over southern China are generally more (less) than normal in El Niño (La Niña) winter. It is because that the transports of aerosols from South and Southeast Asia to southern China are enhanced (weakened), which mask the better (worse) scavenging conditions for aerosols in El Niño (La Niña) winter. The probability density function (PDF) of the simulated daily surface concentrations of aerosols over southern China indicates that the region tends to have less clean and moderate (heavy) haze days, but more heavy (moderate) haze days in El Niño (La Niña) winter.

scholarly journals Precipitação em Rio Grande – RS (1913 – 2016): Análise descritiva e da variabilidade

2021 ◽  
Vol 14 (2) ◽  
pp. 537
Author(s):  
Tamires Da Rosa Silva ◽  
Ítalo Reis ◽  
Eliana Klering ◽  
Eder Bayer Maier
Keyword(s):  
Standard Deviation ◽  
El Niño ◽  
Temporal Variability ◽  
El Nino ◽  
Temporal Distribution ◽  
Rio Grande ◽  
Precipitation Variability ◽  
La Niña ◽  
Extreme Precipitation Events ◽  
La Nina

O objetivo desse artigo é analisar a variabilidade temporal da precipitação em Rio Grande – RS, no período entre 1913 e 2016. Para isso foram utilizadas técnicas estatísticas descritivas e inferencial para caracterizar a distribuição da precipitação em diferentes escalas de tempo e para identificar os ciclos temporais da ocorrência de secas e chuvas acima da média e suas relações com os fenômenos remotos. As análises mostram que a precipitação mensal em Rio Grande varia entre 0,3mm e 551,8mm, com uma média de 102,1 mm e desvio padrão de 66,1 mm; o total anual da precipitação variou entre 625 mm e 2.261,9 mm, com uma média de 1.226 mm; a média mensal tem uma amplitude de 71,2 mm e 126,7 mm, sendo as médias de dezembro e setembro, respectivamente; e são os meses do verão e o outono que apresentaram maior e menor variabilidade da precipitação. Os ciclos temporais da ocorrência de secas e chuvas acima da média ocorreram predominantemente na escala interanual e está associado predominantemente aos fenômenos ENOS e ODP, sendo mais comum a ocorrência de chuvas acima da média/secas concomitantes ao El Niño/La Niña. Não sendo raro a ocorrência de secas e chuvas acima da média, visto que foram identificados 219 meses de seca e 210 meses de chuvas excessivas no período entre 1913 e 2016, adotando um limiar de |56,4 mm| da anomalia da precipitação.Palavras-chave: Precipitação, variabilidade, wavelet, Rio Grande.                                                                                                                                 Precipitation in the city of Rio Grande – RS (1913 – 2016): Descriptive and variability analysis A B S T R A C T The aim was to analyze the temporal variability of rainfall in Rio Grande - RS, during the years 1913-2016, in order to understand the temporal distribution, using descriptive statistical techniques to characterize the monthly and annual total, the monthly averages, the anomalies, the occurrence of extreme events and inferential techniques in order to characterize the main remote factors controlling precipitation variability. The results of these descriptive analyzes show that the monthly rainfall in Rio Grande varies between 0.3mm and 551.8mm with an average of 102.1mm and standard deviation of 66.1mm; the total annual precipitation indicated a variation between 625 mm (minimum) and 2,261.9 mm (maximum), with an average annual accumulation of 1,226 mm; the monthly average varies between 71.2 mm and 126.7 mm, referring to the months of December and September, respectively; estimation of standard deviation showed summer and autumn as the months with the highest and lowest variations, respectively. Temporal variability occurred at the interannual and interdecenal scales and are predominantly associated with the ENSO/ODP phenomenon, with more than average rainfall occurrin /droughts concomitant with El Niño/La Niña.  Anomalies above | 56.4 mm | were considered extreme precipitation events and was identified with the technique of quartiles, 219 months of drought and 210 months of excessive rainfall in the period between 1913 and 2016.Keywords: Precipitation, variability, wavelet, Rio Grande.

scholarly journals Different El Niño Types and Tropical Cyclone Landfall in East Asia

2012 ◽  
Vol 25 (19) ◽  
pp. 6510-6523 ◽  
Author(s):  
Wei Zhang ◽  
H.-F. Graf ◽  
Yee Leung ◽  
Michael Herzog
Keyword(s):  
Tropical Cyclone ◽  
East Asia ◽  
El Niño ◽  
El Nino ◽  
The Philippines ◽  
La Niña ◽  
Malay Peninsula ◽  
Cp El Niño ◽  
La Nina ◽  
Ep El Niño

Abstract This study examines whether there exist significant differences in tropical cyclone (TC) landfall between central Pacific (CP) El Niño, eastern Pacific (EP) El Niño, and La Niña during the peak TC season (June–October) and how and to what extent CP El Niño influences TC landfall over East Asia for the period 1961–2009. The peak TC season is subdivided into summer [June–August (JJA)] and autumn [September–October (SO)]. The results are summarized as follows: (i) during the summer of CP El Niño years, TCs are more likely to make landfall over East Asia because of a strong easterly steering flow anomaly induced by the westward shift of the subtropical high and northward-shifted TC genesis. In particular, TCs have a greater probability of making landfall over Japan and Korea during the summer of CP El Niño years. (ii) In the autumn of CP El Niño years, TC landfall in most areas of East Asia, especially Indochina, the Malay Peninsula, and the Philippines, is likely to be suppressed because the large-scale circulation resembles that of EP El Niño years. (iii) During the whole peak TC season [June–October (JJASO)] of CP El Niño years, TCs are more likely to make landfall over Japan and Korea. TC landfall in East Asia as a whole has an insignificant association with CP El Niño during the peak TC season. In addition, more (less) TCs are likely to make landfall in China, Indochina, the Malay Peninsula, and the Philippines during the peak TC season of La Niña (EP El Niño) years.

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 ENSO Effect on Interannual Variability of Spring Aerosols over East Asia

2020 ◽  
Author(s):  
Anbao Zhu ◽  
Haiming Xu ◽  
Jiechun Deng ◽  
Jing Ma ◽  
Shuhui Li
Keyword(s):  
East Asia ◽  
Interannual Variability ◽  
El Niño ◽  
El Nino ◽  
Transport Processes ◽  
La Niña ◽  
Carbonaceous Aerosol ◽  
Indochina Peninsula ◽  
Central Pacific ◽  
La Nina

Abstract. Effects of the El Niño/Southern Oscillation (ENSO) on the interannual variability of spring aerosols over East Asia are investigated using the Modern Era Retrospective analysis for Research and Applications Version 2 (MERRA-2) reanalysis aerosol data. Results show that the ENSO has a crucial effect on the spring aerosols over the Indochina Peninsula, southern China and the ocean south of Japan. The above-normal (below-normal) aerosols are found over these regions during the El Niño (La Niña) ensuing spring. In contrast to the local aerosol diffusion in winter, the ENSO affects East Asian aerosols in the following spring mainly via modulating upstream aerosol generation and transport processes. The underlying physical mechanism is that during the El Niño (La Niña) ensuing spring, the dry (wet) air and less (more) precipitation are beneficial for the increase (reduction) of biomass burning activities over the northern Indochina Peninsula, resulting in more (less) carbonaceous aerosol emissions. On the other hand, the anomalous anticyclone (cyclone) over the western North Pacific (WNP) associated with El Niño (La Niña) enhances (weakens) the low-level southwesterly wind from the northern Indochina Peninsula to southern Japan, which transports more (less) carbonaceous aerosol downstream. Anomalous precipitation plays a role in reducing aerosols over the source region, but its washout effect over the downstream region is limited. The ENSO’s impact on the ensuing spring aerosols is mainly attributed to the eastern Pacific ENSO rather than the central Pacific ENSO.

scholarly journals Impacts of ENSO On The Seasonal Transition From Summer to Winter in East Asia

2021 ◽  
Author(s):  
Sunyong Kim ◽  
Jong-Seong Kug
Keyword(s):  
East Asia ◽  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Southern Oscillation ◽  
Temperature Drop ◽  
La Niña ◽  
Boreal Summer ◽  
Seasonal Transition ◽  
La Nina

Abstract The El Niño-Southern Oscillation (ENSO) has seasonally distinct impacts on the East Asian climate so that its seasonal transition depends on the phases of El Niño and La Niña. Here, we investigate the seasonal transition of surface temperature in East Asia from boreal summer to winter based on the warm/cold ENSO developing phases. During La Niña years, from summer to winter the continuous temperature drop in East Asia tends to be faster than that during El Niño, indicating a latter start and earlier termination of fall. This different seasonal transition in East Asia according to phases of ENSO is mostly explained by atmospheric responses to the seasonally-dependent tropical/subtropical precipitation forcings in ENSO developing phases. The anomalous positive precipitation in the subtropical North Pacific exists only in September and leads to the subtropical cyclonic flow during El Niño years. The resultant northerly anomalies on the left side of subtropical cyclone are favorable for transporting cold advection towards East Asia. However, the positive subtropical precipitation disappears and teleconnection to East Asia is strongly controlled by the negative precipitation anomalies in the western North Pacific, modulating the anticyclonic anomalies in East Asia during the early winter (November). Therefore, these seasonally sharp precipitation changes associated with ENSO evolution induce distinctive teleconnection changes from northerly (summer) to southerly (winter) anomalies, which eventually affect seasonal transition in East Asia. Also, the Coupled Model Intercomparison Project Phase 5 models reasonably simulate the relatively rapid temperature transition in East Asia during La Niña years, supporting the observational argument.

scholarly journals Variabilidade Espaco-Temporal da Precipitação na Amazônia durante Eventos ENOS (Spatio-temporal Variability of Precipitation in the Amazon during ENOS Events)

2015 ◽  
Vol 8 (1) ◽  
pp. 013
Author(s):  
Adriano Marlison Sousa ◽  
Edson José Paulino da Rocha ◽  
Maria Isabel Vitorino ◽  
Paulo Jorge Oliveira Ponte de Souza ◽  
Marcel Nascimento Botelho
Keyword(s):  
El Niño ◽  
El Nino ◽  
Surface Condition ◽  
La Niña ◽  
Multiple Time ◽  
La Nina ◽  
Intraseasonal Oscillations ◽  
Spatio Temporal ◽  
The Difference

As relações entre o ENOS e a precipitação na Amazônia são analisadas num contexto espacial e temporal. Para isso, foram utilizados os dados mensais de precipitação de 238 estações distribuídas nos estados do Amazonas, Amapá, Pará e Maranhão, no período de 1920 a 2011. A identificação dos eventos de El Niño e La Niña foi feita através da análise dos campos de anomalias de precipita-ção, e foi aplicada a transformada em Ondeleta Morlet para a caracterização de todas as oscilações presentes no sinal da precipitação para o período estudado. Os resultados mostram que a distribuição espacial das anomalias positivas e negativas é bastante heterogênea, devido às interações das diferentes dimensões de tempo e escala do fenômeno ENOS e das condições de superfície da Ama-zônia. A diferença entre os eventos de El-Niño de 1982/83 e 1997/98 está relacionado à maior atua-ção em área com anomalias negativas, causando uma redução na precipitação no leste da Amazônia. Observou-se que os eventos de ENOS foram modulados por oscilações de precipitações de múlti-plas escala de tempo, tais como: decadal, interdecadal, anual e intrasazonal. Já as oscilações intrasa-zonais estiveram relacionas apenas ao evento de La-Niña 1984/85.  A B S T R A C T This study examined the relationship between ENSO and precipitation in the Amazon in a spatial and temporal. For this, we used the monthly data of precipitation of 238 stations distributed in the states of Amazonas, Amapá, Pará and Maranhão (period 1970 – 2011). For the analysis of data were made calculations of anomalies of precipitation, to identify the events of El Niño and La Niña, and application of the Wavelet Transform into Morlet to the characterization of oscillations in the sign of precipitation. The results show that the spatial distribution of positive and negative anomalies is quite heterogeneous, because the interactions of the different dimensions of time and scale of the ENSO phenomena and the surface condition of the Amazon. The difference between the events of El Niño of 1982/83 and 1997/98, be related to increased activity in an area with negative anomalies, causing a decrease in precipitation in eastern Amazonia. It was observed that the events of ENSO have been modulated by oscillations of precipitation of multiple time scale, such as decadal, interdecadal, annual and intraseasonal. It was noted also that the intraseasonal oscillations were related only to the La-Niña event in 1984/85. Keywords: Wavelets Morlet, Water Resources, extreme events.  

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