scholarly journals Observational analysis of the daily cycle of the planetary boundary layer in the central Amazon during a non-El Niño year and El Niño year (GoAmazon project 2014/5)

2020 ◽  
Vol 20 (9) ◽  
pp. 5547-5558 ◽  
Author(s):  
Rayonil G. Carneiro ◽  
Gilberto Fisch
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Microwave Radiometer ◽  
Enso Event ◽  
Strong Impact ◽  
Daily Cycle ◽  
Central Amazon

Abstract. The Amazon biome contains more than half of the remaining tropical forests of the planet and has a strong impact on aspects of meteorology such as the planetary boundary layer (PBL). In this context, the objective of this study was to conduct observational evaluations of the daily cycle of the height of the PBL during its stable (night) and convective (day) phases from data that were measured and/or estimated using instruments such as a radiosonde, sodar, ceilometer, wind profiler, lidar and microwave radiometer installed in the central Amazon during 2014 (considered a typical year) and 2015 during which an intense El Niño–Southern Oscillation (ENSO) event predominated during the GoAmazon experiment. The results from the four intense observation periods (IOPs) show that during the day and night periods, independent of dry or rainy seasons, the ceilometer is the instrument that best describes the depth of the PBL when compared with in situ radiosonde measurements. Additionally, during the dry season in 2015, the ENSO substantially influenced the growth phase of the PBL, with a 15 % increase in the rate compared to the same period in 2014.

scholarly journals Observational analysis of the daily cycle of the planetary boundary layer in the central amazon during a typical year and under the influence of the ENSO (GoAmazon project 2014/5)

2019 ◽  
Author(s):  
Rayonil G. Carneiro ◽  
Gilberto Fisch
Keyword(s):  
Boundary Layer ◽  
Tropical Forests ◽  
Planetary Boundary Layer ◽  
Southern Oscillation ◽  
Microwave Radiometer ◽  
Enso Event ◽  
Strong Impact ◽  
Daily Cycle ◽  
Central Amazon

Abstract. The Amazon biome contains more than half of the remaining tropical forests of the planet and has a strong impact on aspects of meteorology such as the Planetary Boundary Layer (PBL). In this context, the objective of this study was to conduct observational evaluations of the daily cycle of the height of the PLB during its stable (night) and convective (day) phases from data that were measured and/or estimated using instruments such as a radiosonde, SODAR, ceilometer, wind profiler, Lidar and microwave radiometer installed in the central Amazon during 2014 (considered a typical year) and 2015 during which an intense El Niño Southern Oscillation (ENSO) event predominated during the GOAmazon experiment. The results from the four intense observation periods (IOPs) show that during the day and night periods, independent of dry or rainy seasons, the ceilometer is the instrument that best describes the depth of the PBL when compared with in situ radiosonde measurements. Additionally, during the dry season in 2015, the ENSO substantially influenced the growth phase of the PBL, with a 15 % increase in the rate compared to the same period in 2014.

scholarly journals Effects of Tropical Cyclones on ENSO

2019 ◽  
Vol 32 (19) ◽  
pp. 6423-6443 ◽  
Author(s):  
Tao Lian ◽  
Jun Ying ◽  
Hong-Li Ren ◽  
Chan Zhang ◽  
Ting Liu ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Heat Content ◽  
Coupled Model ◽  
Enso Event ◽  
Central Pacific ◽  
Final State ◽  
Enso Dynamics

AbstractNumerous studies have investigated the role of El Niño–Southern Oscillation (ENSO) in modulating the activity of tropical cyclones (TCs) in the western Pacific on interannual time scales, but the effects of TCs on ENSO are less discussed. Some studies have found that TCs sharply increase surface westerly anomalies over the equatorial western–central Pacific and maintain them there for a few days. Given the strong influence of equatorial surface westerly wind bursts on ENSO, as confirmed by much recent literature, the effects of TCs on ENSO may be much greater than previously expected. Using recently released observations and reanalysis datasets, it is found that the majority of near-equatorial TCs (simply TCs hereafter) are associated with strong westerly anomalies at the equator, and the number and longitude of TCs are significantly correlated with ENSO strength. When TC-related wind stresses are added into an intermediate coupled model, the simulated ENSO becomes more irregular, and both ENSO magnitude and skewness approach those of observations, as compared with simulations without TCs. Adding TCs into the model system does not break the linkage between the heat content anomaly and subsequent ENSO event in the model, which manifest the classic recharge–discharge ENSO dynamics. However, the influence of TCs on ENSO is so strong that ENSO magnitude and sometimes its final state—that is, either El Niño or La Niña—largely depend on the number and timing of TCs during the event year. Our findings suggest that TCs play a prominent role in ENSO dynamics, and their effects must be considered in ENSO forecast models.

scholarly journals Hemispheric transport and influence of meteorology on global aerosol climatology

2012 ◽  
Vol 12 (16) ◽  
pp. 7609-7624 ◽  
Author(s):  
T. L. Zhao ◽  
S. L. Gong ◽  
P. Huang ◽  
D. Lavoué
Keyword(s):  
Boundary Layer ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Late Summer ◽  
Late Winter ◽  
Aerosol Transport ◽  
Transport Pathways ◽  
Annual Variations ◽  
Annual Variability

Abstract. Based on a 10-yr simulation with the global air quality modeling system GEM-AQ/EC, the northern hemispheric aerosol transport with the inter-annual and seasonal variability as well as the mean climate was investigated. The intercontinental aerosol transport is predominant in the zonal direction from west to east with the ranges of inter-annual variability between 14% and 63%, and is 0.5–2 orders of magnitude weaker in the meridional direction but with larger inter-annual variability. The aerosol transport is found to fluctuate seasonally with a factor of 5–8 between the maximum in late winter and spring and the minimum in late summer and fall. Three meteorological factors controlling the intercontinental aerosol transport and its inter-annual variations are identified from the modeling results: (1) Anomalies in the mid-latitude westerlies in the troposphere. (2) Variations of precipitation over the intercontinental transport pathways and (3) Changes of meteorological conditions within the boundary layer. Changed only by the meteorology, the aerosol column loadings in the free troposphere over the source regions of Europe, North America, South and East Asia vary inter-annually with the highest magnitudes of 30–37% in January and December and the lowest magnitudes of 16–20% in August and September, and the inter-annual aerosol variability within the boundary layer influencing the surface concentrations with the magnitudes from 6% to 20% is more region-dependent. As the strongest climatic signal, the El Niño-Southern Oscillation (ENSO) can lead the anomalies in the intercontinental aerosols in El Niño- and La Niña-years respectively with the strong and weak transport of the mid-latitude westerlies and the low latitude easterlies in the Northern Hemisphere (NH).

Cultural Responses to Environmental Catastrophes: Post-El Niño Subsistence on the Prehistoric North Coast of Peru

1991 ◽  
Vol 2 (1) ◽  
pp. 27-47 ◽  
Author(s):  
Jerry D. Moore
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Enso Event ◽  
North Coast ◽  
Archaeological Data ◽  
Enso Events ◽  
The North ◽  
Cultural Responses ◽  
North Coast Of Peru

Recent debate about the development of complex societies on the north coast of Peru has turned on the relative importance of marine vs. terrestrial resources and the extent to which different resource zones are upset by El Niño/Southern Oscillation (ENSO) events. While ENSO events are cited frequently as having important consequences for Prehispanic Andean societies, in fact there are few archaeological data about the nature of cultural responses to a specific ENSO event. Archaeological data from two Chimu settlements in the Casma Valley, Peru—Quebrada Sta. Cristina and Manchan—document the occurrence of a fourteenth-century A.D. ENSO event and some of the cultural responses to that prehistoric El Niño.

scholarly journals ANALISIS DAMPAK ENSO (EL-NINO SOUTHERN OSCILLATION) TERHADAP TINGKAT KEKERINGAN UNTUK TANAMAN PANGAN DAN PALAWIJA (STUDI KASUS : SULAWESI SELATAN)

Agromet ◽  
2009 ◽  
Vol 23 (2) ◽  
pp. 182
Author(s):  
Yon Sugiarto ◽  
Dori Kurniawan
Keyword(s):  
El Niño ◽  
Crop Production ◽  
Drought Index ◽  
El Nino ◽  
Southern Oscillation ◽  
Enso Event ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Food Crops ◽  
Weather Changes

<p>Weather and climate variability is a long-term weather changes that are characterized by fluctuations and deviations from normal conditions. One possible cause is the ENSO (El-Nino Southern Oscillation) which affected in drought events. This research was conducted to determine and analyze the level of drought in South Sulawesi due to the influence of ENSO and compare the production of food crops and secondary food crops in normal years and ENSO.<br />Drought index is calculated based on the Palmer method by using data of rainfall, air temperature and soil moisture as input. Based on the calculations using the method of Palmer drought index, the regions with monsoon rain patterns have a range of values between -22.71 drought until 18:23, Equatorial patterns ranging from -4.03 to 5:07, and on local patterns ranged<br />from -8.57 until 10:07. Verification test results on the drought index of crop production data showed that each ENSO event is always followed by a decline in rice production, especially of rice fields. Food crop production generally tends to increase at each ENSO event because most crops are plants that are resistant to drought, particularly local varieties that have adapted well to their environment. Thus, the drought caused by the influence of ENSO can affect the production of food crops and secondary food crops.</p>

scholarly journals How unusual was late 20th century El Niño-Southern Oscillation (ENSO)? Assessing evidence from tree-ring, coral, ice-core and documentary palaeoarchives, A.D. 1525-2002

2006 ◽  
Vol 6 ◽  
pp. 173-179 ◽  
Author(s):  
J. L. Gergis ◽  
A. M. Fowler
Keyword(s):  
20Th Century ◽  
Tree Ring ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Southern Oscillation ◽  
Enso Event ◽  
Late 20Th Century ◽  
Enso Events ◽  
Proxy Records

Abstract. Multiple proxy records (tree-ring, coral, ice and documentary) were examined to isolate ENSO signals associated with both phases of the phenomenon for the period A.D. 1525-2002. To avoid making large-scale inferences from single proxy analysis, regional signals were aggregated into a network of high-resolution records, revealing large-scale trends in the frequency, magnitude and duration of pre-instrumental ENSO using novel applications of percentile analysis. Here we use the newly introduced coupled ocean-atmosphere ENSO index (CEI) as a baseline for the calibration of proxy records. The reconstruction revealed 83 extreme or very strong ENSO episodes since A.D. 1525, expanding considerably on existing ENSO event chronologies. Significantly, excerpts of the most comprehensive list of La Niña events complied to date are presented, indicating peak activity during the 16th to mid 17th and 20th centuries. Although extreme events are seen throughout the 478-year reconstruction, 43% of the extreme ENSO events noted since A.D. 1525 occur during the 20th century, with an obvious bias towards enhanced El Niño conditions in recent decades. Of the total number of extreme event years reconstructed, 30% of all reconstructed ENSO event years occur post-1940 alone suggesting that recent ENSO variability appears anomalous in the context of the past five centuries.

Variations of Sea Level and Tidal Behaviour during El Nino/La Nina: An Example of Malaysian Coastline

2015 ◽  
Vol 73 (5) ◽  
Author(s):  
Mohd Hilmi Abdullah ◽  
Mohd Razali Mahmud ◽  
Nor Ainah Amat
Keyword(s):  
Sea Level ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Enso Event ◽  
La Niña ◽  
Observation Data ◽  
Northeast Monsoon ◽  
Tidal Variation ◽  
La Nina

The El Nino/La Nina Southern Oscillation (ENSO) phenomenon indirectly provides dramatic changes to tidal that can cause floods, drought and affect various marine activities. Tidal observation data plays important role in determining the characteristic or behaviour of tide along the coastal area especially during sudden climate change such as the phenomenon of El Nino/La Nina, the Northeast Monsoon, Northwest Monsoon and Tsunami. It is important to study the occurrence of the ENSO event and it characteristic so that it can be used for prediction and monitoring the land and water ecosystem. This research is to identify the variations of sea level and tidal behaviour in Malaysian coastline during El Nino/La Nina. The tidal observation data, meteorology data (temperature and mean sea level pressure), and Southern Oscillation Index (SOI) calculation are used to look on the changes of the tidal variation during the ENSO phenomenon. The results of this research will specially benefit in the determination of tidal level in Malaysia and to the professionals who have responsibilities in policy making, agriculture, environmental planning, economics and marine engineering.

scholarly journals Biogeochemical Responses and Seasonal Dynamics of the Benthic Boundary Layer Microbial Communities during the El Niño 2015 in an Eastern Boundary Upwelling System

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 180
Author(s):  
Verónica Molina ◽  
Marcela Cornejo-D’Ottone ◽  
Eulogio H. Soto ◽  
Eduardo Quiroga ◽  
Guillermo Alarcón ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Microbial Communities ◽  
El Niño ◽  
Bottom Water ◽  
El Nino ◽  
Southern Oscillation ◽  
Amplicon Sequencing ◽  
Benthic Boundary Layer ◽  
Oxygen Utilization ◽  
Eastern Boundary

The Eastern South Pacific coastal zone is characterized by seasonal and interannual variability, driven by upwelling and El Niño Southern Oscillation (ENSO), respectively. These oceanographical conditions influence microbial communities and their contribution to nutrient and greenhouse gases recycling, especially in bottom waters due to oxygenation. This article addresses the seasonal hydrographic and biogeochemical conditions in the water and sediments during El Niño 2015. Bottom water active microbial communities, including nitrifiers, were studied using amplicon sequencing of 16S rRNA (cDNA) and RT-qPCR, respectively. The results of the hydrographic analysis showed changes in the water column associated with the predominance of sub-Antarctic Waters characterized by warmed and low nutrients in the surface and more oxygenated conditions at the bottom in comparison with El Niño 2014. The organic matter quantity and quality decreased during fall and winter. The bottom water active microbial assemblages were dominated by archaea (Ca. Poseidoniales) and putative ammonia oxidizing archaea. Active bacteria affiliated to SAR11, Marinimicrobia and Nitrospina, and oxygen deficient realms (Desulfobacterales, SUP05 clade and anammox) suffered variations, possibly associated with oxygen and redox conditions in the benthic boundary layer. Nitrifying functional groups contributed significantly more during late fall and winter which was consistent with higher bottom water oxygenation. Relationships between apparent oxygen utilization nitrate and nitrous oxide in the water support the contribution of nitrification to this greenhouse gas distribution in the water. In general, our study suggests that seasonal oceanographic variability during an El Niño year influences the microbial community and thus remineralization potential, which supports the need to carry out longer time series to identify the relevance of seasonality under ENSO in Eastern Boundary Upwelling Systems (EBUS) areas.

scholarly journals Contributions from California Coastal-Zone Surface Fluxes to Heavy Coastal Precipitation: A CALJET Case Study during the Strong El Niño of 1998

2005 ◽  
Vol 133 (5) ◽  
pp. 1175-1198 ◽  
Author(s):  
P. Ola G. Persson ◽  
P. J. Neiman ◽  
B. Walter ◽  
J-W. Bao ◽  
F. M. Ralph
Keyword(s):  
Boundary Layer ◽  
Latent Heat ◽  
El Niño ◽  
Model Simulation ◽  
El Nino ◽  
Southern Oscillation ◽  
Surface Flux ◽  
Surface Fluxes ◽  
Heat Fluxes ◽  
Sst Anomalies

Abstract Analysis of the case of 3 February 1998, using an extensive observational system in the California Bight during an El Niño winter, has revealed that surface sensible and latent heat fluxes within 150 km of the shore contributed substantially to the destabilization of air that subsequently produced strong convection and flooding along the coast. Aircraft, dropsonde, and satellite observations gathered offshore documented the sea surface temperatures (SSTs), surface fluxes, stratification, and frontal structures. These were used to extrapolate the effects of the fluxes on the warm-sector, boundary layer air ahead of a secondary cold front as this air moved toward the coast. The extrapolated structure was then validated in detail with nearshore aircraft, wind profiler, sounding, and buoy observations of the frontal convection along the coast, and the trajectory transformations were confirmed with a model simulation. The results show that the surface fluxes increased CAPE by about 26% such that the nearshore boundary layer values of 491 J kg−1 were near the upper end of those observed for cool-season California thunderstorms. The increased CAPE due to upward sensible and latent heat fluxes was a result of the anomalously warm coastal SSTs (+1°–3°C) typical of strong El Niño events. Applications of the extrapolation method using a surface flux parameterization scheme and different SSTs suggested that convective destabilization due to nearshore surface fluxes may only occur during El Niño years when positive coastal SST anomalies are present. The fluxes may have no effect or a stabilizing effect during non–El Niño years, characterized by zero or negative coastal SST anomalies. In short, during strong El Niños, it appears that the associated coastal SST anomalies serve to further intensify the already anomalously strong storms in southern California, thus contributing to the increased flooding. This modulating effect by El Niño–Southern Oscillation (ENSO) of a mesoscale process has not been considered before in attempts at assessing the impacts of ENSO on U.S. west coast precipitation.

scholarly journals Hemispheric transport and influence of meteorology on global aerosol climatology

2012 ◽  
Vol 12 (4) ◽  
pp. 10181-10221 ◽  
Author(s):  
T. L. Zhao ◽  
S. L. Gong ◽  
P. Huang ◽  
D. Lavoué
Keyword(s):  
Boundary Layer ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Late Summer ◽  
Late Winter ◽  
Free Troposphere ◽  
Aerosol Transport ◽  
Transport Pathways ◽  
Annual Variability

Abstract. Based on a 10-yr simulation with the global air quality modeling system GEM-AQ/EC, the inter-annual and seasonal variability as well as the mean climate of hemispheric aerosol transport (HAT) was investigated. The intercontinental aerosol transport is predominant in the zonal direction from west to east with the magnitudes of inter-annual variability between 14% and 63%, and are 0.5–2 orders of magnitude weaker in the meridional direction but with larger inter-annual variability. The HAT is found to fluctuate seasonally with a factor of 5–8 between the maximum in late winter and spring and the minimum in late summer and fall. Three meteorological factors controlling the inter-annual aerosol variations in the source-receptor (S-R) relationships are identified from the modeling results: (1) Anomalies in the mid-latitude westerlies in the troposphere. (2) Variations of precipitation over the intercontinental transport pathways and (3) Changes of meteorological conditions in the boundary layer. Changed only by the meteorology, the aerosol column loadings in the free troposphere over the HTAP-regions vary inter-annually with the highest magnitudes of 30–37% in January and December and the lowest magnitudes of 16–20% in August and September, and the magnitudes of inter-annual variability within the boundary layer influencing the surface concentrations over the HTAP-regions are 30–70% less than in the free troposphere and more region-dependent. As the strongest climatic signal, the El Niño–Southern Oscillation (ENSO) can lead the anomalies in the S-R relationships for intercontinental aerosols in the Northern Hemisphere (NH) with the strong/weak transport in the mid-latitude westerlies and the low latitude easterlies for the HAT in El Niño/ La Niña-years.

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