Effect Of ENSO Research Articles

Differences in the impact of intense ENSO+ in Bahia Magdalena (SW of Baja California, Mexico) in the context of climate change

The Bahia Magdalena-Bahia Almejas (BM-BA) complex is the largest coastal lagoon system in the Mexican Pacific; it is in a transitional zone between temperate and tropical regions. BM-BA has a high biodiversity and is an important source of fishing resources; however, its productivity diminishes during ENSO+ events. This work aimed to compare the impact of the three most intense ENSOs (1982-1983, 1997-1998, and 2015-2016) on their environmental and biological characteristics in the context of global warming. Since 1970, this region has been warming, and the chlorophyll-a is diminishing; however, short-term environmental variations associated with basin-scale processes have modified these trends. The comparison showed that the equatorial influence on the 1997-1998 ENSO was more evident, while the North Pacific conditions and other large-scale environmental processes influenced the other ENSOs: in 1982-1983, the warm signal continued after the ENSO+ ended, and in 2015-2016, it was present before the ENSO+ onset due to the MWH The Blob and probably global warming. High temperatures at the basin scale altered large-scale wind patterns, weakening local upwelling and diminishing the nutrient input. The Equatorial and North Pacific influence on BM varies over time (as expected in a transition zone like BM); however, in recent years, North Pacific warming associated with climate change has probably gained relevance and modulated the effect of ENSO+.

A revisit of the linearity in the combined effect of ENSO and QBO on the stratosphere: model evidence from CMIP5/6

A revisit of the linearity in the combined effect of ENSO and QBO on the stratosphere: model evidence from CMIP5/6

Association of western US compound hydrometeorological extremes with Madden-Julian oscillation and ENSO interaction

Extreme weather and climate events can have substantial impacts on society and the environment. Compound extremes (two or more extreme events occurring simultaneously or successively) may exert even larger impacts than individual events. Here we examine physical drivers behind variability in hydrometeorological (precipitation and temperature) compound extremes on subseasonal-to-seasonal timescales. Observational evidence presented here through composite analysis indicates that compound extreme frequency is linked to the Madden-Julian oscillation, a unique type of organized tropical convection varying primarily on subseasonal-to-seasonal timescales. The linkage between Madden-Julian oscillation and compound extremes is largely dependent on ENSO phases, which can be seen through different magnitudes or changes in sign of the canonical relationship conditioned on ENSO states. Similarly, the Madden-Julian oscillation can interrupt the canonical ENSO-compound extreme relationship. Our results suggest a potential route to improve subseasonal-to-seasonal prediction of western US compound extremes by considering the combined effect of both Madden-Julian oscillation and ENSO.

El Niño–Southern Oscillation-Independent Regulation of Western North Pacific Tropical Cyclone Genesis

El Niño–Southern Oscillation-Independent Regulation of Western North Pacific Tropical Cyclone Genesis

The Effect of ENSO on Seasonal Rainfall Using the Monte-Carlo Bootstrap Method in the Southern Part of Java, Indonesia

The Effect of ENSO on Seasonal Rainfall Using the Monte-Carlo Bootstrap Method in the Southern Part of Java, Indonesia

The Effect of ENSO on Upwelling Intensity in the Seas along the Northern Coast of Papua - Case Study of the 2015–2016 El Niño and the 2010–2011 La Niña Events

The Effect of ENSO on Upwelling Intensity in the Seas along the Northern Coast of Papua - Case Study of the 2015–2016 El Niño and the 2010–2011 La Niña Events

Role of the Australian High in Seasonal Phase Locking of the Indian Ocean Dipole

AbstractThis paper analyzes the effect of the Australian High (AH) on the seasonal phase locking of Indian Ocean Dipole (IOD) events. The anomalous strong AH associated with the positive phase of the Antarctic Oscillation can cause significant easterly wind anomalies and northward cross‐equatorial flow over the western Maritime Continent (MC) by strengthening the Australian winter monsoon during May–August. The AH‐associated easterly anomalies and northward cross‐equatorial flow can create thermodynamic air‐sea feedback and contribute to a significant cooling anomaly in the western MC and the tropical eastern Indian Ocean. Without considering the effect of ENSO, these processes contribute to the occurrence of positive IOD events, which begin in early summer, peak in late summer, and decay rapidly thereafter. The effect of ENSO can extend the peak period of IOD into the boreal autumn of that year. An anomalous weak AH corresponds to the occurrence and seasonal phase locking of negative IOD events. Through combined empirical orthogonal function analysis, we find that the effect of the AH can well explain the seasonal phase locking of 34 IOD events (40 in total), which provides an important theoretical basis for the prediction of IOD events.

Long-term variabilities in thermal structure, CO2 concentration and associated cooling rates in the Earth's middle atmosphere: Observations and model simulations

Enhanced anthropogenic activities in the recent decades are ensuing in the large-scale accumulation of carbon dioxide (CO2) concentration in the Earth's atmosphere. CO2 in the atmosphere induces warming in the troposphere and cooling in the middle atmosphere. A systematic analysis of the middle atmospheric thermal structure and its variability at decadal scale is need of the hour to perceive the consequences of increased anthropogenic activity in totality. In this regard, long-term variations of temperature, CO2 concentration and associated cooling rates in the middle and upper atmosphere (30–110 km) are investigated using Sounding of Atmosphere by Broadband Emission Radiometry (SABER) on board Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics (TIMED) satellite observations during 2002–2021 and Specified Dynamics-Whole Atmosphere Community Climate Model (SD-WACCM) simulations during 2002–2017 over 50 N–50 S latitudes. The results show that CO2 concentration measured by SABER is significantly underestimated by the WACCM simulations, especially above 90 km altitude. In order to find the long-term trends in each variable, Multivariate Linear Regression (MLR) technique is employed to the residual data obtained after removing seasonal variations. SABER observations show decreasing trend in temperature with a rate of 0.5–2.5 K/decade and an increase in CO2 vmr of 16–18 ppmv/decade. The effect of Solar Cycle, QBO and ENSO on each of the variables is also investigated. The significance of the present study lies in evaluating the SD-WACCM simulations of long-term variabilities in the thermal structure, CO2 vmr and associated cooling rates using two decades of observations.

Effect of Extreme ENSO and IOD on the Variability of Chlorophyll-a and Sea Surface Temperature in the North and South of Central Java Province

Chlorophyll-a (chl-a) and Sea Surface Temperature (SST) are important indicators of air-sea interaction and primary productivity. It has been widely known that the variability of chl-a and SST in the waters of Central Java Province (CJP) is influenced by the monsoonal cycle. Previous studies did not clearly describe the variability of chl-a and SST when compared to other cycles. This present study investigated the variability of chl-a and SST influenced by monsoonal cycles, IOD, and ENSO in both CJP waters. Our analysis is based on satellite observations and uses daily data to compile climatological data. The analysis found differences between the variability of chl-a and SST during the monsoonal cycle and ENSO-IOD extreme conditions. During the monsoonal cycle, the maximum (minimum) chl-a (SST) in northern CJP is 0.7 mg.L-1 (28.5ºC) is observed in the West Monsoon, and in the southern CJP is 1.5 mg.L-1 (25.5ºC) is observed in the East Monsoon. In addition, the analysis reveals that the ENSO and IOD extremes do not clearly alter the variability of chl-a and SST in the northern CJP. However, ENSO and IOD extremes have clearly altered the variability of chl-a and SST in the southern CJP. The highest impact to variability of chl-a and SST occurred during IOD+ extreme (2019), where the range of value chl-a (SST) in south CJP is 0,35–4,57 mg.L-1 (23,29 – 30,49ºC). The value of chl-a (SST) is greater than 4 mg.L-1 (less than 24ºC) are observed in the east monsoon. It is caused by the intensity of lifting the mass of water from deeper waters to the sea surface, which possibly supplies the nutrients in the surface waters. The result of the investigation showed that the increasing of chl-a and decreasing of SST in the northern CJP dominant by monsoonal cycle and southern CJP dominant by monsoonal cycle and ENSO – IOD.

Asymmetric effect of ENSO in the decaying stage on the central China July precipitation

Asymmetric effect of ENSO in the decaying stage on the central China July precipitation

Asymmetric effect of ENSO on the maritime continent precipitation in decaying summers

Asymmetric effect of ENSO on the maritime continent precipitation in decaying summers

IMPACT PROFILE OF ENSO AND DIPOLE MODE ON RAINFALL AS ANTICIPATION OF HYDROMETEOROLOGICAL DISASTERS IN THE PROVINCE OF SOUTH SUMATRA

El Niño Southern Oscillation (ENSO) is a weather phenomenon in the Pacific Ocean. At the same time, Dipole Mode (DM) is an ocean-atmosphere interaction phenomenon in the Indian Ocean. The area of South Sumatra Province, which is in the Monsunal area, makes the influence of ENSO and DM very instrumental in determining the length of the rainy season and throughout the year. The South Sumatra region is very vulnerable to forest and land fire disasters due to the condition of the area in the form of swamps and peatlands, which are very easy to burn if the dry season occurs in the South Sumatra area. In this study, an analysis of the effect of ENSO and DM on rainfall in the South Sumatra Region from 1981 to 2020 was carried out using a simple linear regression method and the correlation coefficient using Niño 3.4 index data and Dipole Mode with rainfall data and consecutive rainy days data. Consecutive Wet Day (CWD). The purpose of this study was to determine the effect of Enso and Dipole Mode on rainfall and CWD in the South Sumatra Region. The results show that the correlation between ENSO and rainfall is 0.0017-0.002573, DM and rainfall is 0.05972, and ENSO and CWD is -0.068. The correlation between DMI and CWD is 0.513. So it can be said that ENSO and DMI have no effect on rainfall in the South Sumatra Province. Still, the amount of CWD in South Sumatra Province is significantly determined by the Dipole Mode Index (DMI) at a moderate level. The number of consecutive rainy days in South Sumatra Province is influenced by the dynamics of the ocean and atmosphere of the Indian Ocean, which is characterized by the presence of positive IOD and negative IOD phenomena.

The impact of ENSO-IOD on Decapterus spp. in Pangkajene Kepulauan and Barru Waters, Makassar Strait, Indonesia

Abstract. Baharuddin NAI, Zainuddin M, Najamuddin. 2022. The impact of ENSO-IOD on Decapterus spp. in Pangkajene Kepulauan and Barru Waters, Makassar Strait, Indonesia. Biodiversitas 23: 5613-5622. ENSO and IOD are climate variability that affects water conditions seasonally and inter-annually, including Makassar Strait, Indonesia. Research on the effect of ENSO and IOD variations on water fertility in Makassar Strait requires updating every year. This study aimed to analyze the impact of ENSO and IOD on the variability of oceanography (SST and SSC) and dynamics of the Scad (Decapterus spp.) production in Makassar Strait. This study used Niño3.4 Index and Dipole Mode Index data from NOAA, while SST and SSC data were obtained from the Aqua-MODIS satellite imagery from January 2015 to December 2019. For the study, data were processed using SeaDAS, ArcGIS, and RStudio software. The results indicated that the Niño3.4 Index for SST and SSC was strong, and the Dipole Mode Index for SST and SSC was low. The time-series graph showed that the El Niño event was strong, and the IOD+ was quite strong in 2015-2016, affecting the negative SST anomaly and the positive SSC anomaly. Cross-correlation analysis of the effect of the Niño3.4 Index with the SST anomaly of -0.62 and the low SSC anomaly of 0.18. The result of IOD on the SST anomaly was quite strong at -0.51, and the SSC anomaly was low at 0.07. Strong El Niño and IOD+ events were found to highly affect SST and SSC as well as influence the variation or fluctuation of Scad catch production, especially from 2015 to 2016 in the study area of Makassar Strait, Indonesia.

Meridional Propagation of Carbon Dioxide (CO2) Growth Rate and Flux Anomalies From the Tropics Due to ENSO

AbstractEl Niño Southern Oscillation (ENSO) influence on carbon dioxide (CO2) growth rates are not spatially uniform or simultaneous around the globe. Using atmospheric CO2 observations and atmospheric chemistry‐transport model (ACTM), we show that anomalies in CO2 fluxes and growth rate originate in the tropics, as an effect of ENSO. The CO2 anomalies are then propagated from the equator toward the poles with asymmetric delays. A maximum delay of about 8 and 4 months are found at the northern hemisphere (NH) and southern hemisphere (SH) high latitudes, respectively. This asymmetric time delay is because of the CO2 flux anomaly mainly originate in the tropical SH land and transport of SH air into the NH is slower than that for NH air into the SH. The poleward increase of time delay is more homogeneous in the upper troposphere, as per the ACTM simulations, but observational evidence suffers from gaps in long‐term measurements.

A Long‐Lasting Precipitation Deficit in South China During Autumn‐Winter 2020/2021: Combined Effect of ENSO and Arctic Sea Ice

AbstractA severe persistent drought occurred in South China during autumn–winter 2020/2021, causing enormous economic losses and severe water shortage in South China. Focusing on this event, this study analyzed the climate anomalies associated with this event, and investigated the underlying mechanisms as well as their relationship with the leading modes of the autumn and winter precipitation in eastern China. The results suggest that the drought in South China during autumn 2020 is mainly attributed to the water vapor divergence anomalies induced by an anomalous anticyclone over eastern China and an anomalous cyclone over the South China Sea, which are caused by an anomalous Eurasian atmospheric wave‐train triggered by the negative sea ice anomalies in the Barents Sea‐Kara Sea region and a La Niña‐like condition in the tropical Pacific sea surface temperatures, respectively. The continued drought in South China during winter 2020/2021 is mainly attributed to the water vapor divergence anomalies induced by an anomalous cyclone over the western North Pacific, which is caused by the continued La Niña‐like condition. The mechanisms of the first two leading modes of autumn precipitation in eastern China both contributed to the drought in South China during autumn 2020, whereas the mechanisms of the first leading mode of winter precipitation in eastern China played an important role in causing the drought in South China during winter 2020/2021. Numerical experiments demonstrate important impact of the ENSO and Arctic sea ice anomalies on the East Asian climate anomalies during autumn–winter 2020/2021.

El Ni\xf1o-Southern Oscillation affects the water relations of tree species in the Yucatan Peninsula, Mexico

We evaluated the effect of ENSO 2015/16 on the water relations of eight tree species in seasonally dry tropical forests of the Yucatan Peninsula, Mexico. The functional traits: wood density, relative water content in wood, xylem water potential and specific leaf area were recorded during the rainy season and compared in three consecutive years: 2015 (pre-ENSO conditions), 2016 (ENSO conditions) and 2017 (post-ENSO conditions). We analyzed tree size on the capacity to respond to water deficit, considering young and mature trees, and if this response is distinctive in species with different leaf patterns in seasonally dry tropical forests distributed along a precipitation gradient (700–1200 mm year−1). These traits showed a strong decrease in all species in response to water stress in 2016, mainly in the driest site. Deciduous species had lower wood density, higher predawn water potential and higher specific leaf area than evergreen species. In all cases, mature trees were more tolerant to drought. In the driest site, there was a significant reduction in water status, regardless of their leaf phenology, indicating that seasonally dry tropical forests are highly vulnerable to ENSO. Vulnerability of deciduous species is intensified in the driest areas and in the youngest trees.

The Effect of ENSO and IOD on The Variability of Sea Surface Temperature and Rainfall in The Natuna Sea

The Natuna Sea is located at the northwestern part of Indonesia. Previous studies had showed that ENSO has a stronger impact on SST than chlorophyll-a. According to several studies, Indonesian oceans are heavily impacted by IOD. This study uses SST data with high-resolution satellite imagery (MODIS and Pathfinder) and rainfall and wind data from the Reanalysis Model (ERA-5) which is processed using a composite method and correlation grid. This research results, when La-Niña negative IOD SST will decrease 1°C and rainfall rises 7 mm/day while when El-Niño IOD positive SST will increase by 1°C while in rainfall will decrease by 3 mm/day. The variation of SST and rainfall is more influenced by ENSO than IOD.

Interdecadal Change in the Relationship between the Winter North Pacific Storm Track and the East Asian Winter Monsoon

AbstractBased on the daily NCEP reanalysis, the present study investigates the interdecadal change in the relationship between the winter North Pacific storm track (WNPST) and the East Asian winter monsoon (EAWM), and evaluates the WNPST–EAWM relationship in 17 CMIP6 models. The results show that the out-of-phase WNPST–EAWM relationship underwent an interdecadal change in the mid-1980s. The WNPST–EAWM relationship became less significant during period 2 (P2; 1990–2015). The atmospheric circulation anomaly related to the EAWM during period 1 (P1; 1955–80) is more robust than that during P2. The interdecadal weakening WNPST–EAWM relationship may be attributed to the interdecadal damping WNPST–EAWM interaction. The EAWM-related anomalous baroclinic energy conversion and moisture effects, including meridional and vertical eddy moisture fluxes, contribute to the significant attenuation of the WNPST during P1. The transient eddy-induced dynamic forcing and thermal forcing anomalies, as well as the barotropic process represented by the local Eliassen–Palm flux divergence associated with WNPST, can also significantly manipulate the upper-tropospheric jet during P1. However, the atmospheric circulation and interaction between the WNPST and EAWM during P2 are not as significant as those during P1. The effect of ENSO on the WNPST is significantly different before and after the mid-1980s. After the mid-1980s, the WNPST shows the characteristic of moving equatorward during El Niño events. It seems that ENSO takes over the WNPST from the EAWM after the mid-1980s. In addition, except for BCC-ESM1, CanESM5, and SAM0-UNICON, most of the CMIP6 models cannot reproduce the significant out-of-phase WNPST–EAWM relationship.

The classification of upwelling indicators base on sea surface temperature, chlorophyll-a and upwelling index, the case study in Southern Java to Timor Waters

The Understanding of the existence of upwelling, which concerning location, onset and ending, top temporally, strength, extent area are very important for the management of marine waters, especially fishing and conservation. A method is needed to identify the area of upwelling base on its indicators. The one method that is needed is to classify the upwelling indicator. The aim of the research is fist studying the method classification of upwelling criteria base on SST, chlorophyll-a and upwelling index. Second, apply classification of upwelling criteria for mapping upwelling area on four case climate variability and third examine the effect of ENSO and IOD on the variability of the upwelling area. The research result, based on SST, chlorophyll-a and upwelling index in the Indian Ocean south of Java to Timor with statistical methods, have successfully divided upwelling criteria into 4: weak upwelling, medium upwelling, strong upwelling and very strong upwelling. Based on the upwelling criteria, we can apply mapping the location of upwelling, to determine the spatial distribution and extent of upwelling in Indian Ocean waters southern of Java to Timor. Two indicators of upwelling SST and chlorophyll-a are more accurate in the application if be used together. The variability of ENSO and IOD significantly effected growing and reducing the range of upwelling indicator (SST, chlorophyll-a and upwelling index), but the IOD index much greater effecting than ENSO index (SOI).

Oxygen stable isotopes of a network of shrubs and trees as high-resolution plaeoclimatic proxies in Northwestern China

Tree rings play an important role in high-resolution paleoclimate reconstruction over large areas. Nevertheless, the sampling sites of most existing tree-ring networks are unevenly distributed due to the limitations of the availability of appropriate tree species and sampling conditions. In light of the good spatial representation provided by tree-ring stable oxygen isotope ratio (δ18O), we selected several shrubs (Hippophae rhamnoides L.) found in near-glacier valleys, conifer (Picea crassifolia Komarov) trees in alpine meadows, and broad-leaved (Populus euphratica Olivier) trees found in deserts. Although the three sampling sites were each 250–360 km apart, with varied site conditions and very distinct species, we observed coherent variations in the δ18O of the three species within a common time interval. The average correlation coefficient was found to be 0.674 (p < 0.001, n = 30) among annual-ring δ18O series of three species. All annual-ring δ18O of three species demonstrated significant negative correlations with relative humidity (RH) and precipitation, and significant positive correlations with temperature, in spring and summer. The correlation coefficient between the first principal component (PC1) of the δ18O variations in the three species and the regional summer (June to August) RH was found to be −0.855 (p < 0.001, n = 30). In addition, PC1 showed variations similar to those of δ18O in precipitation. Spatial correlation demonstrated that PC1 represents the hydroclimatic variability that occurs in most of central-western China. Significant correlations with sea-level pressure and several East Asian Summer Monsoon indices indicated that PC1 was affected by the large-scale atmospheric circulation pattern and could be used as an indicator of monsoon moisture. PC1 correlated significantly with ten annually resolved hydroclimatic series in central-western China, demonstrating the potential of establishing a tree-ring climate network with uniform spatial distribution using multi-species tree-ring δ18O. The results from these series suggest that an abrupt climate change occurred in 1979. After 1979, PC1 correlated significantly with the summer-season EI Nino Modoki index (r = 0.474, p < 0.02, n = 24). This implied that the effect of the central Pacific ENSO on the variability in monsoon moisture in China became more prominent after the abrupt climate change in 1979.