scholarly journals Eigendecomposition filtering and reconstruction of the climatic indexes for the Brazilian Northeast

2018 ◽  
Vol 40 ◽  
pp. 51
Author(s):  
Cleber Souza Corrêa ◽  
Roberto Lage Guedes ◽  
Karlmer Abel Bueno Corrêa
Keyword(s):  
Time Series ◽  
Southern Oscillation Index ◽  
Decadal Variability ◽  
Southern Oscillation ◽  
Global Scale ◽  
Northeastern Brazil ◽  
Time Period ◽  
The Pacific ◽  
Behavior Characteristics ◽  
Brazilian Northeast

This work seeks through the intermediary of the eigendecomposition filtering and reconstructing technique the signal of the time series of Southern Oscillation Index (SOI), and analyze possible cycles that can be observed in this SOI time series. The technique of decomposition was very consistent and can show possible trends in cycles in time series of SOI. The final result is featuring a composition of components operating in the formation of the SOI variability signal, the first component is featuring approximately 1.33, 2.66, 3.58, 4.83 years and decadal time period, larger scales and periods, matching a variance approximately of 70% of the signal of the SOI time series. In addition to the influence of cycles of solar activity, associated with its number of sunspots, the variability observed from 20 to 27 years may be related to the interaction between Pacific Decadal Oscillation (PDO) and Southern Oscillation Index (SOI). The understanding the dynamics that control the decadal variability in the Pacific Ocean and its interactions with climate change on a global scale. These results can be correlated to behavior characteristics of the atmospheric dynamics and predominance in northeastern Brazil, has importance and affecting activities in Rocket Launch Centre in Alcântara (CLA).

scholarly journals Renewed methane increase for five years (2007–2011) observed by solar FTIR spectrometry

2012 ◽  
Vol 12 (11) ◽  
pp. 4885-4891 ◽  
Author(s):  
R. Sussmann ◽  
F. Forster ◽  
M. Rettinger ◽  
P. Bousquet
Keyword(s):  
Time Series ◽  
Confidence Interval ◽  
Global Scale ◽  
Future Trend ◽  
Time Interval ◽  
Positive Trend ◽  
Time Period ◽  
New Period ◽  
Natural Wetlands ◽  
Surface Network

Abstract. Trends of column-averaged methane for the time period (1996, Sep 2011) are derived from the mid-infrared (mid-IR) solar FTIR time series at the Zugspitze (47.42° N, 10.98° E, 2964 m a.s.l.) and Garmisch (47.48° N, 11.06° E, 743 m a.s.l.). Trend analysis comprises a fit to the de-seasonalized time series along with bootstrap resampling for quantifying trend uncertainties. We find a positive trend during [1996, 1998] of 9.0 [3.2, 14.7] ppb yr−1 for Zugspitze (95% confidence interval), an insignificant growth during [1999, mid 2006] of 0.8 [−0.1, 1.7] ppb yr−1 (Zugspitze), and a significant renewed increase during [mid 2006, Sep 2011] of 5.1 [4.2, 6.0] ppb yr−1 for Garmisch, which is in agreement with 4.8 [3.8, 5.9] ppb yr−1 for Zugspitze. The agreement of methane trends at the two closely neighboring FTIR sites Zugspitze and Garmisch within the uncertainties indicates a good station-to-station consistency as a basis for future trend analyses by the ground-based mid-IR FTIR network on the global scale. Furthermore, the Zugspitze FTIR trend for the time interval [Jul 2006, Jun 2009] is found to agree with the trend derived from SCIAMACHY (WFM-DOAS v2.0.2) data within the 95% confidence intervals. In case a 1000-km pixel selection radius around the Zugspitze is used, the confidence interval is narrower for the FTIR trend (6.9 [4.2, 9.5] ppb yr−1) compared to SCIAMACHY (7.1 [5.1, 8.6] ppb yr−1). If, however, a loosened pixel selection is used (≈1000-km half-width latitudinal band), the SCIAMACHY trend significance interval is narrower (6.8 [5.1, 8.6] ppb yr−1) compared to Zugspitze FTIR (5.7 [3.0, 8.3] ppb yr−1). While earlier studies using surface network data revealed changes of 8.0 ± 0.6 ppb in 2007, 6.4 ± 0.6 ppb in 2008, and 4.7 ± 0.6 ppb in 2009 (Dlugokencky et al., 2011), our updated result proves that the renewed methane increase meanwhile has been persisting for >5 years [mid 2006, Sep 2011]. This is either the longest and largest positive trend anomaly since the beginning of systematic observations more than 25 years ago or the onset of a new period of strongly increasing CH4 levels in the atmosphere. Several scenarios have been developed to explain the persistent increase observed, mainly invoking an increase in emissions from natural wetlands, an increase in fossil fuel-related emissions or a decrease in OH concentrations. However, more work is needed to fully attribute this increase to a particular source or sink.

scholarly journals Decadal Variability of the ENSO Teleconnection to the High-Latitude South Pacific Governed by Coupling with the Southern Annular Mode*

2006 ◽  
Vol 19 (6) ◽  
pp. 979-997 ◽  
Author(s):  
Ryan L. Fogt ◽  
David H. Bromwich
Keyword(s):  
High Latitude ◽  
Decadal Variability ◽  
Southern Oscillation ◽  
Phase Relationship ◽  
South Pacific ◽  
Southern Annular Mode ◽  
Height Anomaly ◽  
Austral Spring ◽  
Annular Mode ◽  
The Pacific

Abstract Decadal variability of the El Niño–Southern Oscillation (ENSO) teleconnection to the high-latitude South Pacific is examined by correlating the European Centre for Medium-Range Weather Forecasts (ECMWF) 40-yr Re-Analysis (ERA-40) and observations with the Southern Oscillation index (SOI) over the last two decades. There is a distinct annual contrast between the 1980s and the 1990s, with the strong teleconnection in the 1990s being explained by an enhanced response during austral spring. Geopotential height anomaly composites constructed during the peak ENSO seasons also demonstrate the decadal variability. Empirical orthogonal function (EOF) analysis reveals that the 1980s September–November (SON) teleconnection is weak due to the interference between the Pacific–South American (PSA) pattern associated with ENSO and the Southern Annular Mode (SAM). An in-phase relationship between these two modes during SON in the 1990s amplifies the height and pressure anomalies in the South Pacific, producing the strong teleconnections seen in the correlation and composite analyses. The in-phase relationship between the tropical and high-latitude forcing also exists in December–February (DJF) during the 1980s and 1990s. These results suggest that natural climate variability plays an important role in the variability of SAM, in agreement with a growing body of literature. Additionally, the significantly positive correlation between ENSO and SAM only during times of strong teleconnection suggests that both the Tropics and the high latitudes need to work together in order for ENSO to strongly influence Antarctic climate.

scholarly journals Observation-Based Estimates of Global and Basin Ocean Meridional Heat Transport Time Series

2019 ◽  
Vol 32 (14) ◽  
pp. 4567-4583 ◽  
Author(s):  
Kevin E. Trenberth ◽  
Yongxin Zhang ◽  
John T. Fasullo ◽  
Lijing Cheng
Keyword(s):  
Time Series ◽  
Interannual Variability ◽  
Annual Cycle ◽  
Decadal Variability ◽  
Southern Oscillation ◽  
Heat Content ◽  
Ocean Basin ◽  
Energy Budgets ◽  
Meridional Heat Transport ◽  
The Mean

Abstract Ocean meridional heat transports (MHTs) are deduced as a residual using energy budgets to produce latitude versus time series for the globe, Indo-Pacific, and Atlantic. The top-of-atmosphere (TOA) radiation is combined with the vertically integrated atmospheric energy divergence from atmospheric reanalyses to produce the net surface energy fluxes everywhere. The latter is then combined with estimates of the vertically integrated ocean heat content (OHC) tendency to produce estimates of the ocean heat divergence. Because seasonal sea ice and land runoff effects are not fully considered, the mean annual cycle is incomplete, but those effects are small for interannual variability. However, there is a mismatch between 12-month inferred surface flux and the corresponding OHC changes globally, requiring adjustments to account for the Earth’s global energy imbalance. Estimates are greatly improved by building in the constraint that MHT must go to zero at the northern and southern extents of the ocean basin at all times, enabling biases between the TOA and OHC data to be reconciled. Zonal mean global, Indo-Pacific, and Atlantic basin ocean MHTs are computed and presented as 12-month running means and for the mean annual cycle for 2000–16. For the Indo-Pacific, the tropical and subtropical MHTs feature a strong relationship with El Niño–Southern Oscillation (ENSO), and in the Atlantic, MHT interannual variability is significantly affected by and likely influences the North Atlantic Oscillation (NAO). However, Atlantic and Pacific changes are linked, suggesting that the northern annular mode (as opposed to NAO) is predominant. There is also evidence of decadal variability or trends.

scholarly journals On the progress of the 2015–2016 El Niño event

2016 ◽  
Vol 16 (4) ◽  
pp. 2007-2011 ◽  
Author(s):  
Costas A. Varotsos ◽  
Chris G. Tzanis ◽  
Nicholas V. Sarlis
Keyword(s):  
Time Series ◽  
El Niño ◽  
Southern Oscillation Index ◽  
El Nino ◽  
Southern Oscillation ◽  
Linear Dynamics ◽  
El Niño Event ◽  
Non Linear ◽  
El Niño Events ◽  
Index Time Series

Abstract. It has been recently reported that the current 2015–2016 El Niño could become "one of the strongest on record". To further explore this claim, we performed the new analysis described in detail in Varotsos et al. (2015) that allows the detection of precursory signals of the strong El Niño events by using a recently developed non-linear dynamics tool. In this context, the analysis of the Southern Oscillation Index time series for the period 1876–2015 shows that the running 2015–2016 El Niño would be rather a "moderate to strong" or even a "strong" event and not “one of the strongest on record", as that of 1997–1998.

scholarly journals A unified proxy for ENSO and PDO variability since 1650

2010 ◽  
Vol 6 (1) ◽  
pp. 1-17 ◽  
Author(s):  
S. McGregor ◽  
A. Timmermann ◽  
O. Timm
Keyword(s):  
El Niño ◽  
Decadal Variability ◽  
El Nino ◽  
Southern Oscillation ◽  
Enso Events ◽  
The Pacific ◽  
Low Pass ◽  
Change In The Mean ◽  
Proxy Reconstructions ◽  
Common Signal

Abstract. In this manuscript we have attempted to consolidate the common signal in previously defined proxy reconstructions of the El Niño-Southern Oscillation into one individual proxy titled the Unified ENSO Proxy (UEP). While correlating well with the majority of input reconstructions, the UEP provides better representation of observed indices of ENSO, discrete ENSO events and documented historical chronologies of ENSO than any of these input ENSO reconstructions. Further to this, the UEP also provides a means to reconstruct the PDO/IPO multi-decadal variability of the Pacific Ocean as the low-pass filtered UEP displays multi-decadal variability that is consistent with the 20th century variability of the PDO and IPO. The UEP is then used to describe changes in ENSO variability which have occurred since 1650 focusing on changes in ENSOs variance, multi-year ENSO events, PDO-like multi-decadal variability and the effects of volcanic and solar forcing on ENSO. We find that multi-year El Niño events similar to the 1990–1995 event have occurred several times over the last 3 1/2 centuries. Consistent with earlier studies we find that volcanic forcing can induce a statistically significant change in the mean state of ENSO in the year of the eruption and a doubling of the probability of an El Niño (La Niña) event occurring in the year of (three years after) the eruption.

scholarly journals Global responses of terrestrial productivity to contemporary climatic oscillations

2008 ◽  
Vol 363 (1504) ◽  
pp. 2779-2785 ◽  
Author(s):  
F.I Woodward ◽  
M.R Lomas ◽  
T Quaife
Keyword(s):  
Time Series ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Gross Primary Production ◽  
Ecosystem Structure ◽  
Climatic Oscillations ◽  
Enso Events ◽  
The Pacific ◽  
Wide Range

The terrestrial biosphere is subjected to a wide range of natural climatic oscillations. Best known is the El Niño–southern oscillation (ENSO) that exerts globally extensive impacts on crops and natural vegetation. A 50-year time series of ENSO events has been analysed to determine those geographical areas that are reliably impacted by ENSO events. Most areas are impacted by changes in precipitation; however, the Pacific Northwest is warmed by El Niño events. Vegetation gross primary production (GPP) has been simulated for these areas, and tests well against independent satellite observations of the normalized difference vegetation index. Analyses of selected geographical areas indicate that changes in GPP often lead to significant changes in ecosystem structure and dynamics. The Pacific decadal oscillation (PDO) is another climatic oscillation that originates from the Pacific and exerts global impacts that are rather similar to ENSO events. However, the longer period of the PDO provided two phases in the time series with a cool phase from 1951 to 1976 and a warm phase from 1977 to 2002. It was notable that the cool phase of the PDO acted additively with cool ENSO phases to exacerbate drought in the earlier period for the southwest USA. By contrast in India, the cool phase of the PDO appears to reduce the negative impacts of warm ENSO events on crop production.

Sea Surface Temperatures along the Coast of British Columbia: Regional Evidence for a Warming Trend

1990 ◽  
Vol 47 (2) ◽  
pp. 346-350 ◽  
Author(s):  
Howard J. Freeland
Keyword(s):  
British Columbia ◽  
Time Series ◽  
Large Scale ◽  
Southern Oscillation ◽  
Warming Trend ◽  
Global Scale ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Mean Values ◽  
Surface Temperatures

Sea-surface temperature has been measured at a large number of sites around the coast of British Columbia for periods well in excess of 50 yr. These time series are long enough to give clear evidence of a large scale secular warming. For the purposes of this paper the daily SST observations are decimated to monthly mean values. The observations are of particular value because observation methods have remained invariant throughout the observation period, and many of the stations are remote from civilisation allowing trends to be estimated that have not been contaminated with urbanization effects. Eighteen out of nineteen stations that are currently being sampled show a warming trend, the one that shows a cooling trend is the shortest time series, only in its eleventh year. The sea-surface temperatures at sites exposed to the Pacific Ocean show very high coherence with global scale air temperature variations but no relationship to the El Niño/Southern Oscillation signal.

scholarly journals ANALISIS KEJADIAN EL NINO TAHUN 2015 DAN PENGARUHNYA TERHADAP PENINGKATAN TITIK API DI WILAYAH SUMATERA DAN KALIMANTAN

2016 ◽  
Vol 17 (1) ◽  
pp. 11 ◽  
Author(s):  
Ardila Yananto ◽  
Saraswati Dewi
Keyword(s):  
Pacific Ocean ◽  
El Niño ◽  
Southern Oscillation Index ◽  
Rainfall Intensity ◽  
El Nino ◽  
Southern Oscillation ◽  
Walker Circulation ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Temporal And Spatial

IntisariKejadian El Nino yang berdampak pada sebagian besar wilayah Indonesia akan selalu berasosiasi dengan kekeringan akibat dari berkurangnya intensitas curah hujan. Lebih jauh akibat dari kekeringan tersebut telah menimbulkan meningkatnya titik api secara signifikan dibandingkan dengan tahun-tahun sebelumnya khususnya di wilayah Sumatera dan Kalimantan, dimana hal tersebut telah mengakibatkan terjadinya bencana asap pada tahun 2015. Tujuan utama penulisan karya tulis ini adalah untuk menganalisis kejadian El Nino pada tahun 2015 dan pengaruhnya terhadap peningkatan titik api di wilayah Sumatera dan Kalimantan baik dalam skala temporal maupun spasial. Dari hasil penelitian ini dapat diketahui bahwa berdasarkan parameter NINO 3.4 SST Indeks dan Southern Oscillation Index (SOI) pada tahun 2015 telah terjadi fenomana El Nino pada level kuat yang ditandai dengan adanya pelemahan sirkulasi walker sehingga pusat tekanan rendah perpindah dari Samudera Pasifik bagian Barat ke Samudera Pasifik bagian Timur, dimana hal ini telah menyebabkan adanya penurunan intensitas curah hujan (anomali negatif) disebagian besar wilayah Indonesia terutama pada bulan Juli hingga Oktober 2015 dan oleh karena itulah pada bulan Juli hingga Oktober 2015 tersebut terjadi peningkatan jumlah titik api yang sangat tajam di wilayah Indonesia dimana persebaran titik api tersebut sebagian besar terkonsentrasi di Provinsi Sumatera Selatan dan Kalimantan Tengah. AbstractEl Nino that impact most areas of Indonesia will always be associated in drought due to reduced rainfall intensity. Drought, in further, has resulted in increasing titik apis significantly compared to previous years, especially in the Sumatra and Kalimantan, that was creating smog disaster in 2015. The main objective of this research was to analyze the occurrence of El Nino in 2015 and its influence on increase of titik api in Sumatera and Kalimantan both in temporal and spatial scale. From this research it is known that based on the NINO 3.4 SST index and the Southern Oscillation Index (SOI) it is known there was a strong El Niño event occurred in 2015 showed there was a weakening Walker circulation so that the low pressure center moved from Western part of the Pacific Ocean to the Eastern Pacific Ocean, where this has led to a decrease rainfall intensity (negative anomaly) in most parts of Indonesia, especially from July to October 2015 and because of that from July to October 2015 there was very hight increasing number of titik apis in Indonesia where the spread of titik api the mostly concentrated in the province of South Sumatera and Central Kalimantan. 

scholarly journals A unified proxy for ENSO and PDO variability since 1650

2009 ◽  
Vol 5 (5) ◽  
pp. 2177-2222 ◽  
Author(s):  
S. McGregor ◽  
A. Timmermann ◽  
O. Timm
Keyword(s):  
El Niño ◽  
Decadal Variability ◽  
El Nino ◽  
Southern Oscillation ◽  
Enso Events ◽  
The Pacific ◽  
Low Pass ◽  
Change In The Mean ◽  
Proxy Reconstructions ◽  
Common Signal

Abstract. In this manuscript we have attempted to consolidate the common signal in previously defined proxy reconstructions of the El Niño-Southern Oscillation into one individual proxy titled the Unified ENSO Proxy (UEP). While correlating well with the majority of input reconstructions, the UEP provides better representation of observed indices of ENSO, discrete ENSO events and documented historical chronologies of ENSO than any of these input ENSO reconstructions. Further to this, the UEP also provides a means to reconstruct the PDO/IPO multi-decadal variability of the Pacific Ocean as the low-pass filtered UEP displays multi-decadal variability that is consistent with the 20th century variability of the PDO and IPO. The UEP is then used to describe changes in ENSO variability which have occurred since 1650 focusing on changes in ENSOs variance, multi-year ENSO events, PDO-like multi-decadal variability and the effects of volcanic and solar forcing on ENSO. We find that multi-year El Niño events similar to the 1990–1995 event have occurred several times over the last 3 1/2 centuries. Consistent with earlier studies we find that volcanic forcing can induce a statistically significant change in the mean state of ENSO in the year of the eruption and a doubling of the probability of an El Niño (La Niña) event occurring in the year of (three years after) the eruption.

scholarly journals Previsão de velocidade do vento em termos de médias mensais e horárias a partir da combinação dos modelos Holt-Winters e Redes Neurais Artificiais (Forecast wind speed in terms of monthly and hourly averages from the combination of the Holt-Winters...)

2017 ◽  
Vol 10 (5) ◽  
pp. 1391
Author(s):  
Henrique Do Nascimento Camelo ◽  
Paulo Sérgio Lucio ◽  
João Verçosa Leal Junior
Keyword(s):  
Artificial Intelligence ◽  
Time Series ◽  
Wind Speed ◽  
Hybrid Model ◽  
Northeastern Brazil ◽  
Percentage Error ◽  
Wind Speed Prediction ◽  
Wind Potential ◽  
Speed Prediction ◽  
Brazilian Northeast

O presente artigo propõe a criação de modelo híbrido combinado a partir de modelos de série temporal com inteligência artificial, com o objetivo de fornecer previsões de médias mensais e horárias da velocidade do vento em regiões do nordeste brasileiro. Métodos para previsão de velocidade do vento podem constituir em técnica útil no setor de geração eólica, por exemplo, sendo capaz de adquirir informações importantes de que maneira o potencial eólico local poderá ser aproveitado para possível geração de energia elétrica. É possível constatar a eficiência do modelo híbrido em fornecer perfeitos ajustes aos dados observados, sendo essa afirmativa baseada nos baixos valores encontrados na análise estatística de erros, por exemplo, com erro percentual de aproximadamente 5,0%, e também com o valor do coeficiente de eficiência de Nash-Sutcliffe, cujo valor encontrado em aproximadamente de 0,96. Esses resultados certamente foram importantes nas precisões das séries temporais previstas da velocidade do vento, fazendo com que pudessem acompanhar o perfil das séries temporais observadas da velocidade do vento, principalmente revelando maiores semelhanças de valores máximos e mínimos entre ambas as séries, e mostrando assim, a capacidade do modelo em representar características de sazonalidades local. A importância de fornecer garantias na estimativa da intensidade da velocidade do vento de uma região poderá ser tarefa de auxílio em tomada de decisão no setor de energia.  A B S T R A C TThe present article proposes the creation of hybrid model combined from time series models with artificial intelligence, aiming to provide forecasts of monthly and hourly wind speed averages in regions of northeastern Brazil. Wind speed prediction methods may be a useful technique in the wind power sector, for example, being able to acquire important information about how local wind potential can be harnessed for possible electric power generation. It is possible to verify the efficiency of the hybrid model in providing perfect adjustments to the data observed, being this affirmation based on the low values found in the statistical analysis of errors, for example, with percentage error of approximately 5.0%, and also with the coefficient value Of Nash-Sutcliffe efficiency, whose value was found to be approximately 0.96. These results were certainly important in the precisions of the predicted time series of the wind velocity, so that they could follow the profile of the observed time series of the wind speed, mainly revealing greater similarities of maximum and minimum values between both series, the ability of the model to represent characteristics of local seasonalities. The importance of providing assurances in the estimation of the wind speed intensity of a region may be a decision aid in the energy sector.Keywords: time series, artificial intelligence, wind energy, brazilian northeast. 

Sign in / Sign up

Export Citation Format

Share Document