scholarly journals Effects of the hydrological cycle on the phycoperiphyton assemblage in an Andean foothill stream in Colombia

2016 ◽  
Vol 75 (s1) ◽  
Author(s):  
María I. Ríos-Pulgarín ◽  
Isabel C. Gil-Guarín ◽  
Mario Barletta ◽  
Néstor J. Mancera-Rodríguez
Keyword(s):  
El Niño ◽  
Environmental Changes ◽  
Hydrological Cycle ◽  
El Nino ◽  
Southern Oscillation ◽  
Taxonomic Composition ◽  
Variation Pattern ◽  
Hydroclimatic Variation ◽  
Physical And Chemical ◽  
Number Of Individuals

The Guarinó River is a torrential system that is located in the foothills of the Colombian central Andean mountains that naturally experiences severe hydrological disturbances, which were higher during the Niño-Niña/Southern Oscillation (ENSO) between 2007 and 2010. The seasonal and interannual variabilities in the taxonomic composition, richness and density of phycoperiphyton assemblages (ecological descriptors) from the Guarinó River were examined in relation to the physical and chemical environmental changes associated with the hydrological cycle between 2007 and 2010. The values of the ecological descriptors and environmental variables were analysed via ANOVA, ANCOVA and Canonical Discriminant Analysis to establish temporal patterns and relationships between the variables. Eighty-seven taxa belonging to Cyanobacteria, Chlorophyta, Charophyta, Ochrophyta, Cryptophyta, Euglenozoa and Dinophyta were identified. Flow, water temperature and dissolved oxygen corresponded with the hydroclimatic variation and allowed for the differentiation of the El Niño and La Niña periods. Phycoperiphyton density differences matched the environmental variation pattern with a significant annual increase in the number of individuals during El Niño, whereas annual differences related to richness were not evident. The replacement of genera according to their drag or desiccation tolerance and the persistence of genera tolerant to high hydrological disturbances, such as <em>Fragilaria, Nitzschia, Gomphonema, Navicula </em>and especially<em> Lyngbya</em>, was observed.

scholarly journals The role of the hydrological cycle on the temporal patterns of macroinvertebrate assemblages in an Andean foothill stream in Colombia

2016 ◽  
Vol 75 (s1) ◽  
Author(s):  
María I. Ríos-Pulgarín ◽  
Mario Barletta ◽  
María C. Arango-Jaramillo ◽  
Néstor J. Mancera-Rodríguez
Keyword(s):  
El Niño ◽  
Environmental Changes ◽  
Hydrological Cycle ◽  
El Nino ◽  
Southern Oscillation ◽  
Environmental Parameters ◽  
Functional Feeding Groups ◽  
Feeding Groups ◽  
Hydrological Variability ◽  
Physical And Chemical

The seasonal and interannual changes in the structure, composition and functional feeding groups of the macroinvertebrate assemblage of the Guarinó River, a torrential system located in the Colombian Andean foothills, were examined in relation to the physical and chemical environmental changes associated with the hydrological cycle and the El Niño-Niña/Southern Oscillation (ENSO) between 2007 and 2010. Benthic samples were collected at three sites in the lower sections of the river. A total of 127 taxa were collected in the study, with the total taxonomic richness per site ranging from 82 to 96 taxa and benthos density averaging 5.41 ind. m<sup>-2</sup>. The density showed a tendency to decrease in periods of maximum river level and flow, particularly during La Niña phenomena, and to increase in dry periods, especially in the third year (2009-2010) during El Niño phenomena. The presence and abundance of taxa, functional feeding groups and life habits were regulated by environmental parameters associated with hydrological variability, derived of ENSO phenomena, especially flow rate values. The assemblage showed high taxonomic and functional diversity, which is characteristic of ecosystems affected by recurrent hydrological disturbances, exhibiting differentiated responses based on adaptive strategies against the local hydrologic regime that allow fast recovery under conditions like ENSO phenomena. Such responses include composition changes according to adaptations to different hydrological scenarios, the predominance of generalist trophic guilds and taxa with plasticity in their habits and range of environmental tolerance.

The role of El Niño Southern Oscillation on the patterns of cycling rates observed over India during the monsoon season

2014 ◽  
Vol 5 (4) ◽  
pp. 696-706 ◽  
Author(s):  
T. V. Lakshmi Kumar ◽  
K. Koteswara Rao ◽  
R. Uma ◽  
K. Aruna
Keyword(s):  
Water Vapor ◽  
El Niño ◽  
Hydrological Cycle ◽  
El Nino ◽  
Southern Oscillation ◽  
Monsoon Season ◽  
Precipitable Water ◽  
Spatiotemporal Variability ◽  
Monsoon Period ◽  
Sw Monsoon

Trend and interannual variability of total integrated precipitable water vapor (PWV) has been studied over India for the period 1979–2004 using NCEP/National Centre for Atmospheric Research reanalysis data with 2.5° × 2.5° resolution. The spatiotemporal variability of cycling rates (CR; units: per day), obtained from the ratio of rainfall to the PWV were presented not only for the long term (1979–2004) but also during El Niño (EN) and La Niña (LN) years of the study period to understand the intensity of hydrological cycle. The paper then dwells on obtaining the monthly atmospheric residences times over India to infer the stay of water vapor before it precipitates. The results of the present study are: all India PWV shows decreasing trend in association with the increasing/decreasing trends of Niño 3 SST/Southern Oscillation Index (SOI) for the southwest (SW) monsoon period of 1979–2004; the spatial pattern of temporal correlations of CR with SOI and Niño 3 SST displayed the significant positive and negative values in peninsular and central Indian portions of India respectively; all India atmospheric residence times varied from 9 to 2 days from premonsoon/post monsoon to SW monsoon over India.

scholarly journals El Niño, La Niña, and the global sea level budget

Ocean Science ◽  
2016 ◽  
Vol 12 (6) ◽  
pp. 1165-1177 ◽  
Author(s):  
Christopher G. Piecuch ◽  
Katherine J. Quinn
Keyword(s):  
Sea Level ◽  
El Niño ◽  
Hydrological Cycle ◽  
El Nino ◽  
Southern Oscillation ◽  
Heat Content ◽  
Global Ocean ◽  
Surface Warming ◽  
Enso Events ◽  
The Pacific

Abstract. Previous studies show that nonseasonal variations in global-mean sea level (GMSL) are significantly correlated with El Niño–Southern Oscillation (ENSO). However, it has remained unclear to what extent these ENSO-related GMSL fluctuations correspond to steric (i.e., density) or barystatic (mass) effects. Here we diagnose the GMSL budget for ENSO events observationally using data from profiling floats, satellite gravimetry, and radar altimetry during 2005–2015. Steric and barystatic effects make comparable contributions to the GMSL budget during ENSO, in contrast to previous interpretations based largely on hydrological models, which emphasize the barystatic component. The steric contributions reflect changes in global ocean heat content, centered on the Pacific. Distributions of ocean heat storage in the Pacific arise from a mix of diabatic and adiabatic effects. Results have implications for understanding the surface warming slowdown and demonstrate the usefulness of the Global Ocean Observing System for constraining Earth's hydrological cycle and radiation imbalance.

Mid- to late Holocene cooling events in the Korean Peninsula and their possible impact on ancient societies

2019 ◽  
Vol 92 (1) ◽  
pp. 98-108 ◽  
Author(s):  
Mark Constantine ◽  
Minkoo Kim ◽  
Jungjae Park
Keyword(s):  
El Niño ◽  
Late Holocene ◽  
Environmental Changes ◽  
El Nino ◽  
Southern Oscillation ◽  
Eastern China ◽  
Carbon Isotopic Composition ◽  
Sunspot Activity ◽  
Substantial Impact ◽  
Carbon Isotopic

AbstractWe present a multiproxy record using pollen, magnetic susceptibility, carbon isotopic composition, carbon/nitrogen ratio, and particle size of mid- to late Holocene environmental changes based on a sediment core from the Pomaeho lagoon on the east coast of Korea. The records indicate that climate deteriorations around 6400 cal yr BP and 4000 cal yr BP caused rapid vegetation changes in the study area, which were presumably attributable to low sunspot activity and strong El Niño–like conditions, respectively. These two cooling events were likely modulated by different climate mechanisms, as El Niño–Southern Oscillation activity began to strengthen around 5000 cal yr BP. These events may have had a substantial impact on ancient societies in the study area. Combining our results with archaeological findings indicated that climate deterioration led to drastic declines in local populations around 6400 cal yr BP, 4400 cal yr BP, and 4000 cal yr BP. Because of its high population, coastal East Asia (e.g., eastern China, Japan, and Korea) is particularly vulnerable to potential cooling events in the future. Therefore, there is a strong need for detailed paleoclimate information in this region.

scholarly journals The role of the Amazon Basin moisture in the atmospheric branch of the hydrological cycle: a Lagrangian analysis

2014 ◽  
Vol 18 (7) ◽  
pp. 2577-2598 ◽  
Author(s):  
A. Drumond ◽  
J. Marengo ◽  
T. Ambrizzi ◽  
R. Nieto ◽  
L. Moreira ◽  
...  
Keyword(s):  
El Niño ◽  
Amazon Basin ◽  
Hydrological Cycle ◽  
El Nino ◽  
Southern Oscillation ◽  
La Niña ◽  
Specific Humidity ◽  
Tropical Atlantic ◽  
La Nina

Abstract. We used a Lagrangian model (FLEXPART) together with the 1979–2012 ERA-Interim reanalysis data to investigate the role of the moisture in the Amazon Basin in the regional hydrological budget over the course of the year. FLEXPART computes budgets of evaporation minus precipitation by calculating changes in the specific humidity along forward and backward trajectories. The tropical Atlantic is the most important remote moisture source for the Amazon Basin. The tropical North Atlantic (NA) mainly contributed during the austral summer, while the contribution of the tropical South Atlantic (SA) prevailed for the remainder of the year. At the same time, the moisture contribution from the Amazon Basin itself is mainly for moisture supplying the southeastern South America. The 33-year temporal domain allowed the investigation of some aspects of the interannual variability of the moisture transport over the basin, such as the role of the El Niño Southern Oscillation (ENSO) and the Atlantic Meridional Mode (AMM) on the hydrological budget. During the peak of the Amazonian rainy season (from February to May, FMAM) the AMM is associated more with the interannual variations in the contribution from the tropical Atlantic sources, while the transport from the basin towards the subtropics responds more to the ENSO variability. The moisture contribution prevailed from the SA (NA) region in the years dominated by El Niño/positive AMM (La Niña/negative AMM) conditions. The transport from the Amazon towards the subtropics increased (reduced) during El Niño (La Niña) years.

El Niño controls Holocene rabbit and hare populations in Baja California

2015 ◽  
Vol 84 (1) ◽  
pp. 46-56 ◽  
Author(s):  
Isaac A. Hart ◽  
Jack M. Broughton ◽  
Ruth Gruhn
Keyword(s):  
El Niño ◽  
Late Holocene ◽  
Baja California ◽  
El Nino ◽  
Southern Oscillation ◽  
Modern Human ◽  
Taxonomic Composition ◽  
Eastern Pacific ◽  
Long Term Effects ◽  
Animal Populations

The El Niño/Southern Oscillation (ENSO) is a major source of climatic variation worldwide, with significant impacts on modern human and animal populations. However, few detailed records exist on the long-term effects of ENSO on prehistoric vertebrate populations. Here we examine how lagomorph (rabbit and hare) deposition rate, population age structure and taxonomic composition from Abrigo de los Escorpiones, a well-dated, trans-Holocene vertebrate fauna from northern Baja California, Mexico, vary as a function of the frequency of wet El Niño events and eastern Pacific sea-surface temperatures (SSTs) derived from eastern Pacific geological records. Faunal indices vary significantly in response to El Niño-based precipitation and SST, with substantial moisture-driven variability in the middle and late Holocene. The late Holocene moisture pulse is coincident with previously documented changes in the population dynamics of other vertebrates, including humans. As the frequency and intensity of ENSO is anticipated to vary in the future, these results have important implications for change in future vertebrate populations.

scholarly journals Near-Surface Salinity Reveals the Oceanic Sources of Moisture for Australian Precipitation through Atmospheric Moisture Transport

2020 ◽  
Vol 33 (15) ◽  
pp. 6707-6730
Author(s):  
Saurabh Rathore ◽  
Nathaniel L. Bindoff ◽  
Caroline C. Ummenhofer ◽  
Helen E. Phillips ◽  
Ming Feng
Keyword(s):  
El Niño ◽  
Moisture Transport ◽  
Hydrological Cycle ◽  
El Nino ◽  
Southern Oscillation ◽  
Sea Surface Salinity ◽  
Atmospheric Moisture ◽  
Surface Salinity ◽  
Near Surface ◽  
Atmospheric Moisture Transport

AbstractThe long-term trend of sea surface salinity (SSS) reveals an intensification of the global hydrological cycle due to human-induced climate change. This study demonstrates that SSS variability can also be used as a measure of terrestrial precipitation on interseasonal to interannual time scales, and to locate the source of moisture. Seasonal composites during El Niño–Southern Oscillation/Indian Ocean dipole (ENSO/IOD) events are used to understand the variations of moisture transport and precipitation over Australia, and their association with SSS variability. As ENSO/IOD events evolve, patterns of positive or negative SSS anomaly emerge in the Indo-Pacific warm pool region and are accompanied by atmospheric moisture transport anomalies toward Australia. During co-occurring La Niña and negative IOD events, salty anomalies around the Maritime Continent (north of Australia) indicate freshwater export and are associated with a significant moisture transport that converges over Australia to create anomalous wet conditions. In contrast, during co-occurring El Niño and positive IOD events, a moisture transport divergence anomaly over Australia results in anomalous dry conditions. The relationship between SSS and atmospheric moisture transport also holds for pure ENSO/IOD events but varies in magnitude and spatial pattern. The significant pattern correlation between the moisture flux divergence and SSS anomaly during the ENSO/IOD events highlights the associated ocean–atmosphere coupling. A case study of the extreme hydroclimatic events of Australia (e.g., the 2010/11 Brisbane flood) demonstrates that the changes in SSS occur before the peak of ENSO/IOD events. This raises the prospect that tracking of SSS variability could aid the prediction of Australian rainfall.

scholarly journals Recent evolution and associated hydrological dynamics of a vanishing tropical Andean glacier: Glaciar de Conejeras, Colombia

2018 ◽  
Vol 22 (10) ◽  
pp. 5445-5461 ◽  
Author(s):  
Enrique Morán-Tejeda ◽  
Jorge Luis Ceballos ◽  
Katherine Peña ◽  
Jorge Lorenzo-Lacruz ◽  
Juan Ignacio López-Moreno
Keyword(s):  
El Niño ◽  
Hydrological Cycle ◽  
El Nino ◽  
Southern Oscillation ◽  
Glacier Retreat ◽  
Small Scale ◽  
High Temporal Resolution ◽  
Special Focus ◽  
Hydrological Response ◽  
Great Loss

Abstract. Glaciers in the inner tropics are rapidly retreating due to atmospheric warming. In Colombia, this retreat is accelerated by volcanic activity, and most glaciers are in their last stages of existence. There is general concern about the hydrological implications of receding glaciers, as they constitute important freshwater reservoirs and, after an initial increase in melting flows due to glacier retreat, a decrease in water resources is expected in the long term as glaciers become smaller. In this paper, we perform a comprehensive study of the evolution of a small Colombian glacier, Conejeras (Parque Nacional Natural de los Nevados) that has been monitored since 2006, with a special focus on the hydrological response of the glacierized catchment. The glacier shows great sensitivity to changes in temperature and especially to the evolution of the El Niño–Southern Oscillation (ENSO) phenomenon, with great loss of mass and area during El Niño warm events. Since 2006, it has suffered a 37 % reduction, from 22.45 ha in 2006 to 12 ha in 2017, with an especially abrupt reduction since 2014. During the period of hydrological monitoring (June 2013 to December 2017), streamflow at the outlet of the catchment experienced a noticeable cycle of increasing flows up to mid-2016 and decreasing flows afterwards. The same cycle was observed for other hydrological indicators, including the slope of the rising flow limb and the monthly variability of flows. We observed an evident change in the daily hydrograph, from a predominance of days with a purely melt-driven hydrograph up to mid-2016, to an increase in the frequency of days with flows less influenced by melt after 2016. Such a hydrological cycle is not directly related to fluctuations of temperature or precipitation; therefore, it is reasonable to consider that it is the response of the glacierized catchment to retreat of the glacier. Results confirm the necessity for small-scale studies at a high temporal resolution, in order to understand the hydrological response of glacier-covered catchments to glacier retreat and imminent glacier extinction.

scholarly journals CARACTERIZACIÓN DE LA TEMPERATURA SUPERFICIAL DEL MAR Y CLIMATOLOGÍA DE LA BAHÍA DE LA PAZ, B.C.S., MÉXICO

2006 ◽  
Vol 21 (1-2) ◽  
pp. 81
Author(s):  
G. Martínez-Flores ◽  
R. Cervantes Duarte ◽  
E. González-Rodríguez
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
El Niño ◽  
Environmental Changes ◽  
El Nino ◽  
Southern Oscillation ◽  
Original Data ◽  
Sea Surface ◽  
La Paz ◽  
Noaa Avhrr

Se analizaron 4175 imágenes diarias captadas con el sensor NOAA/AVHRR de julio de 1997 a diciembre de 2004, con el propósito de caracterizar la climatología y variación interanual de TSM en la Bahía de La Paz. A partir de la información se generaron 88 meses de anomalías de TSM y se realizó un análisis de componentes principa les (CP). Se obtuvieron tres componentes que explican en su conjunto el 50.32% de la varianza total de los datos originales de anomalías (32.68%, 11.95% y 5.69% respectivamente). El CP1 presenta los valores de correlación más altos al noroeste de la bahía, con un gradiente decreciendo hacia el sureste. Este componente tiene una alta correlación espacial con la batimetría de la bahía, y temporal con respecto a los meses cálidos. Los valores más altos del CP2 se sitúan en el centro de la bahía, decreciendo hacia el noroeste y sureste. Este patrón espacial se ubica en la zona en la que se ha detectado un gran girociclónico, por lo que atribuimos a este componente la influencia de tal efecto de circulación. El CP3 sitúa sumás alta correlación a lo largo de la costa oeste de la bahía, zona fuertemente influenciada por la corriente litoral a lo largo de la costa. Las fluctuaciones en la TSM en la zona y el período de estudio, no presentaron una correlación significativa con respecto al Indice Oscilación Sur y el Indice El Niño Oscilación Sur, probablemente debido a que la Bahía de La Paz tenga rasgos batimétricos y oceanográficos que determinan una respuesta peculiar a los cambios ambientales. Characterization of the sea surface temperature and climatology of the Bay of La Paz, B.C.S., Mexico 4175 daily NOAA/AVHRR sea surface temperature (SST) images from July of 1997 to December of 2004 were analyzed, in order to characterize the climatology and interannual variation of SST in the Bay of La Paz. From this information, 88 months of SST anomalies were estimated and principal components (PC) analysis was performed. Three components were obtained that explain as a whole the 50.32% of the total variance of the original data of anomalies (32.68%, 11.95% and 5.69% res pectively). PC1 displays the higher values of correlation to the northwest of the bay, with a gradient decreasing to wards the southeast. This component has a high spatial correlation with the bathymetry of the bay, and temporal to the warm months. The highest values of PC2 are located in center of the bay, decreasing to wards the northwest and southeast. This spatial pattern is located in the zone where a large cycloniceddy has been detected. For this reason we attributed this component the influence of such circulation effect. PC3 higher correlation lies throughout the westcoast of the bay, a zone strongly influenced by the long shore current. The SST fluctuations in the zone and the period of study did not display a significant correlation with respect to the Southern Oscillation Index or El Niño Southern Oscillation, probably because the Bay of La Paz is an area with bathymetric and oceanographic characteristics that determine a peculiar response to environmental changes.

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