Browsing by Author "Espinoza, Jhan Carlo"
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Item Restricted A reassessment of the suspended sediment load in the Madeira River basin from the Andes of Peru and Bolivia to the Amazon River in Brazil, based on 10 years of data from the HYBAM monitoring programme(Elsevier, 2017-10) Vauchel, Phillippe; Santini, William; Guyot, Jean Loup; Moquet, Jean Sébastien; Martínez, Jean Michel; Espinoza, Jhan Carlo; Baby, Patrice; Fuertes, Oscar; Noriega, Luis; Puita, Oscar; Sondag, Francis; Fraizy, Pascal; Armijos Cardenas, Elisa Natalia; Cochonneau, Gérard; Timouk, Franck; Olivera, Eurides de; Filizola, Naziano; Molina, Jorge; Ronchail, JosyaneThe Madeira River is the second largest tributary of the Amazon River. It contributes approximately 13% of the Amazon River flow and it may contribute up to 50% of its sediment discharge to the Atlantic Ocean. Until now, the suspended sediment load of the Madeira River was not well known and was estimated in a broad range from 240 to 715 Mt yr⁻¹. Since 2002, the HYBAM international network developed a new monitoring programme specially designed to provide more reliable data than in previous intents. It is based on the continuous monitoring of a set of 11 gauging stations in the Madeira River watershed from the Andes piedmont to the confluence with the Amazon River, and discrete sampling of the suspended sediment concentration every 7 or 10 days. This paper presents the results of the suspended sediment data obtained in the Madeira drainage basin during 2002–2011. The Madeira River suspended sediment load is estimated at 430 Mt yr⁻¹ near its confluence with the Amazon River. The average production of the Madeira River Andean catchment is estimated at 640 Mt yr⁻¹ (±30%), the corresponding sediment yield for the Andes is estimated at 3000 t km⁻² yr⁻¹ (±30%), and the average denudation rate is estimated at 1.20 mm yr⁻¹ (±30%). Contrary to previous results that had mentioned high sedimentation rates in the Beni River floodplain, we detected no measurable sedimentation process in this part of the basin. On the Mamoré River basin, we observed heavy sediment deposition of approximately 210 Mt yr⁻¹ that seem to confirm previous studies. But while these studies mentioned heavy sedimentation in the floodplain, we showed that sediment deposition occurred mainly in the Andean piedmont and immediate foreland in rivers (Parapeti, Grande, Pirai, Yapacani, Chimoré, Chaparé, Secure, Maniqui) with discharges that are not sufficiently large to transport their sediment load downstream in the lowlands.Item Open Access Análisis espacio-temporal de las precipitaciones y caudales durante los eventos El Niño (1982-83 y 1997-98) en la costa norte peruana(Universidad Nacional Agraria La Molina, 2014) León Altuna, Karen Beatriz; Chávarri, Eduardo; Espinoza, Jhan CarloEn la presente investigación se ha estudiado la variabilidad temporal y espacial de las precipitaciones a escala interanual (periodo 1963-2009) y, posteriormente, a una escala diaria durante los eventos El Niño de magnitud extraordinaria: 1982-1983 y 1997-1998, en las regiones de Tumbes y Piura. En primer lugar, se regionalizó la precipitación a partir del Método del Vector Regional (MVR) y se calcularon diez índices de precipitación, los cuales se relacionaron con diferentes tipos de El Niño, asociados a anomalías de temperatura superficial del mar en el Pacífico Ecuatorial Central (PC) y Pacífico Ecuatorial Este (PE). Como resultado se obtuvieron dos regiones climáticas: la región costera (menor a los 500 msnm) y la región andina (mayor a 1000 msnm), donde la precipitación se encuentra principalmente asociada al calentamiento del PE y enfriamiento del PC, respectivamente. Entre los 500 a 1000 msnm no se contó con estaciones meteorológicas. Posteriormente, mediante el Análisis de Componentes Principales se obtuvieron patrones diarios de precipitación, los cuales se relacionaron con los caudales y la circulación atmosférica durante los eventos El Niño 1982-83 y 1997-98. Los resultados del segundo modo de variabilidad mostraron dos regiones climáticas similares a las encontradas por el MVR en las que, durante los eventos El Niño, presentó un patrón espacial que opone los eventos de precipitación de ambas regiones. Asimismo, se identificó que la ocurrencia de lluvias intensas durante eventos extremos El Niño se produce durante anomalías de vientos del oeste que provocan la aproximación de la actividad convectiva (desde 140°W) hacia la costa norte peruana (80°W). Este desplazamiento es mucho más rápido durante el evento El Niño 1982-83. Estos patrones son importantes para explicar las causas de las precipitaciones extremas durante El Niño en la costa norte peruana.Item Restricted Assessing precipitation concentration in the Amazon basin from different satellite‐based data sets(Royal Meteorological Society, 2019-06-15) Zubieta Barragán, Ricardo; Saavedra Huanca, Miguel; Espinoza, Jhan Carlo; Ronchail, Josyane; Sulca Jota, Juan Carlos; Drapeau, Guillaume; Martin‐Vide, JavierDaily precipitation concentration in the Amazon basin (AB) is characterized using concentration index (CI), which is computed from HYBAM Observed Precipitation (HOP) data set, for 1980–2009 period. The ability of four satellite precipitation data sets (TMPA V7, TMPA RT, CMORPH and PERSIANN) to estimate CI is evaluated for 2001–2009 period. Our findings provide new information about the spatial irregularity of daily rainfall distribution over the AB. In addition, the spatial distribution of CI values is not completely explained by rainfall seasonality, which highlights the influence of different weather systems over the AB. The results of rainfall concentration indicate that the distribution of daily rainfall is more regular over northwest (northern Peru) and central Andes. Conversely, Roraima region and a large area of Bolivian Amazon register the highest irregularity in the daily rainfall. Bolivian Amazon also represents regions where the large percentage of total rainfall arises from extreme events (>90th percentile). Heavy rainfall episodes over Roraima region are induced by humidity influx come from Caribbean region, while heavy rainfall events over Bolivian Amazon and Andes region are induced by the northwards propagation of cold and dry air along both sides of Andes Mountains, but only propagate in all tropospheric levels for the Andes. The results also show that PERSIANN and TMPA7 data sets better estimates the daily precipitation concentration for whole AB, but with a relative error 8%. CI estimated from satellites does not agree well with HOP over the Andes and northern Peruvian Amazon. On the other hand, the temporal variability of CI can partly be detected using CMORPH and TMPAV7 data sets over the Peruvian Andes, and central and southern Brazil. Errors in CI estimating might be related to inaccurate estimation of daily rainfall. Finally, we conclude that satellite‐based precipitation data sets are useful for analysing rainfall concentration in some regions of AB.Item Restricted Assessment of different precipitation datasets and their impacts on the water balance of the Negro River basin(Elsevier, 2011-07-11) Getirana, A. C. V.; Espinoza, Jhan Carlo; Ronchail, J.; Rotunno Filho, O. C.With the objective of understanding the potential and limitations of available precipitation products for hydrological studies, this paper compares six daily and sub-daily precipitation datasets and their impacts on the water balance of the Negro River basin in the Amazon basin. The precipitation datasets contain gauge-based data [data derived from the Hybam Observatory Precipitation (HOP) dataset and provided by the Climate Prediction Center (CPC)], satellite-based data [the Global Precipitation Climatology Project (GPCP) one-degree daily and TRMM Multisatellite Precipitation Analysis (TMPA) datasets] and model-based data [the NCEP-DOE AMIP-II re-analysis (NCEP-2) and 40-year ECMWF Re-Analysis (ERA-40) datasets]. Each dataset has a common set of meteorological forcing data which are used to run the MGB-IPH hydrological model for the period from January 1998 to August 2002.Item Restricted Basin-scale analysis of rainfall and runoff in Peru (1969–2004): Pacific, Titicaca and Amazonas drainages(Taylor & Francis, 2012-04-03) Lavado Casimiro, Waldo Sven; Ronchail, Josyane; Labat, David; Espinoza, Jhan Carlo; Guyot, Jean-LoupAccording to the Peruvian agricultural ministry, the Pacific watersheds where the great cities and intense farming are located only benefit from 1% of the available freshwater in Peru. Hence a thorough knowledge of the hydrology of this region is of particular importance. In the paper, analysis of this region and of the two other main Peruvian drainages, the Titicaca and Amazonas are reported. Rainfall and runoff data collected by the Peruvian National Service of Meteorology and Hydrology (SENAMHI) and controlled under the Hydrogeodynamics of the Amazon Basin (HyBAm) project is the basis of this basin-scale study that covers the 1969–2004 period. Beyond the strong contrasting rainfall conditions that differentiate the dry coastal basins and the wet eastern lowlands, details are given about in situ runoff and per basin rainfall distribution in these regions, and about their different altitude–rainfall relationships. Rainfall and runoff variability is strong in the coastal basins at seasonal and inter-annual time scales, and related to extreme El Niño events in the Pacific Ocean. However, rainfall and runoff are more regular in the Andes and Amazonas at the inter-annual time scale. Warm sea-surface temperatures in the northern tropical Atlantic tend to produce drought in the southern Andes basins. Moreover, significant trends and change-points are observed in the runoff data of Amazonas basins where rainfall and runoff decrease, especially after the mid-1980s and during the low-stage season. Almost all the coastal basins show some change in minimum runoff during the last 35 years while no change is observed in rainfall. This means that human activity may have changed runoff in this region of Peru, but this hypothesis deserves more study.Item Open Access Central South America(American Meteorological Society, 2017-08) Marengo, J. A.; Espinoza, Jhan Carlo; Alves, L. M.; Ronchail, J.; Baez, J.;The central South America region includes Brazil, Peru, Paraguay, and Bolivia. The 2016 climate conditions were characterized by extreme high temperatures and below-average precipitation in the Amazon and Andean regions, while above-average precipitation was observed in northern Peru and northeastern Paraguay.Item Open Access Central South America(American Meteorological Society, 2018-08) Espinoza, Jhan Carlo; Alves, L. M.; Ronchail, J.; Báez, J.; Takahashi, Ken; Lavado-Casimiro, W.The central South America region includes Brazil, Peru, Paraguay, and Bolivia.Item Restricted Climate variability and extreme drought in the upper Solimões River (western Amazon Basin): understanding the exceptional 2010 drought(American Geophysical Union (AGU), 2011-07) Espinoza, Jhan Carlo; Ronchail, Josyane; Guyot, Jean Loup; Junquas, Clémentine; Vauchel, Philippe; Lavado, Waldo; Drapeau, Guillaume; Pombosa, RodrigoThis work provides an initial overview of climate features and their related hydrological impacts during the recent extreme droughts (1995, 1998, 2005 and 2010) in the upper Solimões River (western Amazon), using comprehensive in situ discharge and rainfall datasets. The droughts are generally associated with positive SST anomalies in the tropical North Atlantic and weak trade winds and water vapor transport toward the upper Solimões, which, in association with increased subsidence over central and southern Amazon, explain the lack of rainfall and very low discharge values. But in 1998, toward the end of the 1997–98 El Niño event, the drought is more likely related to an anomalous divergence of water vapor in the western Amazon that is characteristic of a warm event in the Pacific. During the austral spring and winter of 2010, the most severe drought since the seventies has been registered in the upper Solimões. Its intensity and its length, when compared to the 2005 drought, can be explained by the addition of an El Niño in austral summer and a very warm episode in the Atlantic in boreal spring and summer. As in 2005, the lack of water in 2010 was more important in the southern tropical tributaries of the upper Solimões than in the northern ones.Item Restricted Climatology of extreme cold events in the Central Peruvian Andes during austral Summer: Origin, types and teleconnections(Wiley, 2018-10) Sulca Jota, Juan Carlos; Vuille, Mathias; Roundy, Paul; Takahashi, Ken; Espinoza, Jhan Carlo; Silva Vidal, Yamina; Trasmonte Soto, Grace Liliam; Zubieta Barragán, RicardoThe climatological and large‐scale characteristics of the extreme cold events (ECEs) in the central Peruvian Andes (Mantaro basin (MB)) during austral summer (January–March) are examined using reanalysis, gridded and in‐situ surface minimum temperature (Tmin) data for the 1979‐2010 period. To describe the influence of the Madden‐Julian Oscillation (MJO) on ECEs in the MB, two ECE groups are defined on basis of the sign of the OLR anomalies in the MJO band (30‐100 days, 0‐9 eastward) at (75°W, 12.5°S). Type 1‐ ECEs occur during the suppressed convection phase of the MJO (OLR anomalies ≥ +2 W m²) while Type 2‐ECEs occur during the enhanced convection phase of the MJO (OLR anomalies ≤ ‐2 W m²). ECEs in the MB are associated with the advection of cold and dry air along the east of the Andes through equatorward propagation of extratropical Rossby wave trains (ERWTs). This cold advection weakens the Bolivian High‐Nordeste Low (BH‐NL) system over South America (SA) at upper‐tropospheric levels. The MJO is an important driver of ECEs in the MB, favoring the cold advection along the Andes during specific MJO phases. 59% of Type‐1 ECE's and 86% of Type‐2 ECE's occur in MJO Phases 7‐2. Type‐1 and 2 ECE's feature a weakened BH over SA at upper‐tropospheric levels. For Type‐1, ERWTs emanate from southeastern Africa in MJO Phases 8‐1 while ERWTs are strenghened when crossing the subtropical southern Pacific Ocean during MJO Phases 2 and 7. With respect to Type‐2, MJO Phases 7‐2 feature circumpolar Rossby wave trains propagation toward SA. Ultimately, MJO Phases 7‐2 induce negative Tmin anomalies over MB, while MJO Phases 3‐6 induce positive Tmin anomalies. El Niño and La Niña strengthen negative Tmin anomalies over the MB during MJO Phases 7‐8 while they weaken positive Tmin anomalies over the MB during MJO Phases 3‐6.Item Open Access Comparison of equatorial GPS-TEC observations over an African station and an American station during the minimum and ascending phases of solar cycle 24(European Geosciences Union (EGU), 2013-11) Akala, A. O.; Seemala, G. K.; Doherty, P. H.; Valladares, C. E.; Carrano, C. S.; Espinoza, Jhan Carlo; Oluyo, S.GPS-TEC data were observed at the same local time at two equatorial stations on both longitudes: Lagos (6.52° N, 3.4° E, 3.04° S magnetic latitude), Nigeria; and Pucallpa (8.38° S, 74.57° W, 4.25° N magnetic latitude), Peru during the minimum (2009, 2010) and ascending (2011) phases of solar cycle 24. These data were grouped into daily, seasonal and solar activity sets. The day-to-day variations in vertical TEC (VTEC) recorded the maximum during 14:00-16:00 LT and minimum during 04:00-06:00 LT at both longitudes. Seasonally, during solar minimum, maximum VTEC values were observed during March equinox and minimum during solstices. However, during the ascending phase of the solar activity, the maximum values were recorded during the December solstice and minimum during the June solstice. VTEC also increased with solar activity at both longitudes. On longitude by longitude comparison, the African GPS station generally recorded higher VTEC values than the American GPS station. Furthermore, harmonic analysis technique was used to extract the annual and semi-annual components of the amplitudes of the TEC series at both stations. The semi-annual variations dominated the TEC series over the African equatorial station, while the annual variations dominated those over the American equatorial station. The GPS-TEC-derived averages for non-storm days were compared with the corresponding values derived by the IRI-2007 with the NeQuick topside option. The NeQuick option of IRI-2007 showed better performance at the American sector than the African sector, but generally underestimating TEC during the early morning hours at both longitudes.Item Open Access Compendio de investigaciones en geofísica: trabajos de investigación realizados por estudiantes durante el año 2017(Instituto Geofísico del Perú, 2017) Instituto Geofísico del Perú; Tavera, Hernando; Milla, Marco; Espinoza, Jhan CarloEn el presente compendio se pondrá en conocimiento de la sociedad diversas investigaciones desarrolladas en ámbitos de estudio como la sismología, vulcanología, aeronomía, física atmosférica, entre otros.Item Open Access Concentración de lluvia diaria y su asociación con eventos hidroclimáticos extremos en la cuenca amazónica(Instituto Geofísico del Perú, 2020-02) Zubieta Barragán, Ricardo; Saavedra Huanca, Miguel; Espinoza, Jhan Carlo; Ronchail, Josyane; Sulca Jota, Juan Carlos; Drapeau, Guillaume; Martin-Vide, JavierEl análisis de datos anuales, estacionales o mensuales de precipitación puede conducir a una interpretación limitada de la distribución espacial y temporal de la lluvia diaria debido a que grandes porcentajes del total anual pueden ocurrir en pocos días. Esta alta concentración de lluvia diaria puede causar erosión de suelos, deslizamientos o inundaciones. La concentración de lluvia diaria para toda la cuenca amazónica (CA) es caracterizada empleando un “Índice de Concentración”, el cual es estimado a partir de un producto grillado de precipitación observada para el periodo 1980-2009. Nuestros hallazgos proveen nueva información acerca de la distribución espacial de la lluvia diaria sobre la CA. Los resultados indican que la concentración de lluvia diaria es relativamente baja en Colombia, Ecuador, norte de Perú y los Andes sobre los 1500 m s. n. m., no obstante, es muy alta en regiones del estado de Roraima en el norte de Brasil y la Amazonía boliviana. Esto explica el por qué algunas regiones de Brasil y Bolivia son más frecuentemente afectadas por eventos de lluvia extrema que conllevan a inundaciones. Asimismo, a pesar de la baja concentración de lluvia estimada en los Andes, ello puede contribuir a incrementar la erosión de suelos o deslizamientos, debido a la interrelación con factores como la heterogeneidad de la lluvia, geología, orografía y vegetación andina.Item Restricted Contrasting North–South changes in Amazon wet-day and dry-day frequency and related atmospheric features (1981–2017)(Springer, 2019) Espinoza, Jhan Carlo; Ronchail, Josyane; Marengo, José Antonio; Segura Cajachagua, Hans MikhailThis study provides an updated analysis of the evolution of seasonal rainfall intensity in the Amazon basin, considering the 1981–2017 period and based on HOP (interpolated HYBAM observed precipitation) and CHIRPS (The Climate Hazards Group Infrared Precipitation with Stations) rainfall data sets. Dry and wet day frequencies as well as extreme percentiles are used in this analysis, producing the same results. Dry-day frequency (DDF) significantly increases in the Southern Amazon (p<0.01), particularly during September–November (SON) in the Bolivian Amazon, central Peruvian Amazon and far southern Brazilian Amazon. Consistently, total rainfall in the southern Amazon during SON also shows a significant diminution (p<0.05), estimated at 18%. The increase in SON DDF in the southern Amazon is related to a warming of the northern tropical Atlantic Ocean and a weakening of water vapour flux from the tropical Atlantic Ocean. The increase in DDF in the southern Amazon is related to enhanced wind subsidence (ascendance) over the 10°S–20°S (5°S–5°N) region and to a deficit (excess) of specific humidity at 1000–300 hPa south of 10°S (north of the 5°S), which suggest a reduction of deep convection over southern Amazonia. Subsidence over the southern Amazon shows a significant trend (p<0.01), which can explain the significant increase in DDF. Wet-day frequency (WDF) significantly increases in the northern Amazon, particularly during the March–May (MAM) period (p<0.01), producing an estimated rainfall increase during MAM of 17% (p<0.01) between 1981 and 2017. Significant changes in both WDF and rainfall in northern Amazon have been detected in 1998 (p<0.01). After 1998, the increase in MAM WDF and rainfall is explained by enhanced moisture flux from the tropical North Atlantic Ocean and an increase in deep convection over the northern and northwestern Amazon. These evolutions in DDF and WDF and in the tropical atmosphere occur simultaneously with an increase in sea surface temperature in the northern Atlantic Ocean, particularly after the mid-1990s. These results provide new insight into rainfall variability and climatic features related to increasing dry season length in southern Amazonia. Severe recent droughts may be associated with the increase in DDF in the South. In addition, the increase in MAM rainfall intensity in northern Amazon after 1998 may be associated with several historical floods that occurred after this date.Item Restricted Contrasting regional discharge evolutions in the Amazon basin (1974–2004)(Elsevier, 2009-09-15) Espinoza, Jhan Carlo; Guyot, Jean Loup; Ronchail, Josyane; Cochonneau, Gérard; Filizola, Naziano; Fraizy, Pascal; Labat, David; Oliveira, Eurides de; Ordoñez, Juan Julio; Vauchel, PhillippeFormer hydrological studies in the Amazon Basin generally describe annual discharge variability on the main stem. However, the downstream Amazon River only represents the mean state of the Amazonian hydrological system. This study therefore uses a new data set including daily discharge in 18 sub-basins to analyze the variability of regional extremes in the Amazon basin, after recalling the diversity of the hydrological annual cycles within the Amazon basin. Several statistical tests are applied in order to detect trends and breaks in the time series. We show that during the 1974–2004 period, the stability of the mean discharge on the main stem in Óbidos is explained by opposite regional features that principally involve Andean rivers: a decrease in the low stage runoff, particularly important in the southern regions, and an increase in the high stage runoff in the northwestern region. Both features are observed from the beginning of the nineties. These features are also observed in smaller meridian sub-basins in Peru and Bolivia. Moreover we show that the changes in discharge extremes are related to the regional pluriannual rainfall variability and the associated atmospheric circulation as well as to tropical large-scale climatic indicators.Item Restricted Control of seasonal and inter-annual rainfall distribution on the Strontium-Neodymium isotopic compositions of suspended particulate matter and implications for tracing ENSO events in the Pacific coast (Tumbes basin, Peru)(Elsevier, 2020-01) Moquet, Jean-Sébastien; Morera Julca, Sergio Byron; Turcq, Bruno; Poitrasson, Franck; Roddaz, Martin; Moreira-Turcq, Patricia; Espinoza, Jhan Carlo; Guyot, Jean-Loup; Takahashi, Ken; Orrillo-Vigo, Jhon; Petrick, Susana; Mounic, Stéphanie; Sondag, FrancisThe geochemistry of riverine sediments exported to the oceans is important for paleo-hydro-climatic reconstruction. However, climate reconstruction requires a good understanding of the relationship between geochemistry and hydrological variability and sediment sources. In this study, we analyzed the major elements, the strontium neodymium radiogenic isotopes signatures (⁸⁷Sr/⁸⁶Sr and εNd) and the mineralogy of the suspended particulate matter (SPM) sampled monthly during two hydrologic years (2007–2008, a wet year, and 2010–2011, a normal hydrological year) upstream the Tumbes River outlet. The hydroclimate of this Ecuador-Peru binational basin is particularly sensitive to ENSO (El Niño Southern Oscillation) events. While mineralogy (dominated by illite) and the chemical alteration index (from 75 to 82) remain almost constant along the two hydrological years, ⁸⁷Sr/⁸⁶Sr (0.7115 to 0.7176) and εNd (−7.8 to −1.9) signatures are particularly sensitive to discharge and SPM concentration variations. Along the hydrological year, two sources control the εNd variability: (1) volcanic rocks, which dominate during the dry season, and (2) plutonic/metamorphic sources, whose contribution increases during the wet season. This behavior is confirmed by the correlation between εNd signature and the monthly rainfall contribution from volcanic area (R = 0.58; p-value < 0.01), and also with the daily discharge at the outlet (R = -0.73; p-value < 0.01). For most of the samples, ⁸⁷Sr/⁸⁶Sr is less variable along the hydrological year. However, two exceptional high discharge and SPM concentration conditions sampled exhibit more radiogenic (higher) ⁸⁷Sr/⁸⁶Sr signatures when plutonic/metamorphic rocks derived sediments are released in sufficient quantities to notably change the SPM isotopic Sr value of the Tumbes River. Hence, this study demonstrates that ⁸⁷Sr/⁸⁶Sr and εNd signatures can be used as powerful proxies for paleoclimate reconstructions based on sediment core's analysis in relation with spatial rainfall distribution and intensity in Pacific sedimentary basins submitted to the diversity of ENSO events.Item Restricted Correction of TRMM 3B43 monthly precipitation data over the mountainous areas of Peru during the period 1998-2007(Wiley, 2011-01-13) Condom, Thomas; Rau, Pedro; Espinoza, Jhan CarloIn an attempt to estimate the spatial and temporal behaviour of rainfall over the mountainous areas of the Peruvian Andes, a new in situ monthly rainfall dataset has been collected (1998–2007) and compared with Tropical Rainfall Measuring Mission (TRMM) 3B43 monthly precipitation data for regions located above 3000 m. The reliability of the TRMM 3B43 data varies depending on the root mean squared error ratio (%RMSE) and correlation coefficient. Because of the discrepancy between the two datasets, the use of additive and multiplicative correction models is proposed for the TRMM 3B43 data. In the Peruvian mountain ranges, these correction models better approximate TRMM rainfall monthly values, as already verified for annual values.Item Open Access Cuantificación de la producción de sedimentos fluviales en suspensión, transportados desde los Andes hacia los manglares de Tumbes y Zarumilla(Instituto Geofísico del Perú, 2013-08) Morera Julca, Sergio Byron; Espinoza, Jhan Carlo; Takahashi, Ken; Atoche, D.; Guyot, J. L.; Yerren, J.; Condom, T.Los manglares en el norte del Perú se encuentran concentrados principalmente en la desembocadura de la cuenca binacional Puyango-Tumbes (Perú y Ecuador) y la cuenca Zarumilla. El presente estudio cuantificó y caracterizó la producción de sedimentos (SY) en ambas cuencas tropicales; basándose en información de la estación hidrosedimentológica El Tigre que delimita 4708 km2 (entre 22 y 3875 msnm) y la estación Palmales, que monitorea 639 km2 (entre 42 y 1242 msnm) de la cuenca Zarumilla. La campaña de monitoreo a una alta frecuencia en la cuenca de Zarumilla mostro una alta correlación entre la el caudal sólido y líquido instantáneo. Por otra parte el análisis de la base de datos en la estación El Tigre permitió la construcción de las curvas de gasto líquido (Q) y sólido (Qs). La cuantificación de la SY para los años observados (2004-2012) fluctúa entre 0.47x106 y 9.5x106 t.año-1 , encontrándose un promedio multianual de 1.6x106 t.año-1. El caudal sólido específico (SSY) promedio es 340 t.km-2 .año-1 , del cual el 92% va a ser transportado durante el periodo de lluvias (Ene-Abr), 7% durante transición (May-Jun, Nov-Dic) y solo1% durante el estiaje (Jul-Oct). A ello podemos agregar que durante años normales el 38% del SSY es transportado por caudales entre 300 a 500 m3 .s-1. Finalmente, se estimó el caudal sólido para el periodo 1963-2004 a partir de la curva de gasto sólido (Qs=F(Q)); los resultados muestran que para escenarios similares a los mega Niños del 1982-83 y 1997-98 la SY podría fluctuar entre 5400 a 9721 t.km-2 .año-1 respectivamente (entre 16 y 29 veces más que un año normal), dichas cifras marcarían una de las tasas de erosión más críticas a nivel mundial.Item Open Access Decline of fine suspended sediments in the Madeira River Basin (2003–2017)(MDPI, 2019-03-12) Ayes Rivera, Irma; Armijos Cardenas, Elisa Natalia; Espinoza Villar, Raúl Arnaldo; Espinoza, Jhan Carlo; Molina-Carpio, Jorge; Max Ayala, José; Gutierrez Cori, Omar; Martinez, Jean-Michel; Filizola, NazianoThe Madeira River is the second largest Amazon tributary, contributing up to 50% of the Amazon River’s sediment load. The Madeira has significant hydropower potential, which has started to be used by the Madeira Hydroelectric Complex (MHC), with two large dams along the middle stretch of the river. In this study, fine suspended sediment concentration (FSC) data were assessed downstream of the MHC at the Porto Velho gauging station and at the outlet of each tributary (Beni and Mamoré Rivers, upstream from the MHC), from 2003 to 2017. When comparing the pre-MHC (2003–2008) and post-MHC (2015–2017) periods, a 36% decrease in FSC was observed in the Beni River during the peak months of sediment load (December–March). At Porto Velho, a reduction of 30% was found, which responds to the Upper Madeira Basin and hydroelectric regulation. Concerning water discharge, no significant change occurred, indicating that a lower peak FSC cannot be explained by changes in the peak discharge months. However, lower FSCs are associated with a downward break in the overall time series registered at the outlet of the major sediment supplier—the Beni River—during 2010.Item Open Access Discharge simulation in the sub-basins of the Amazon using ORCHIDEE forced by new datasets(European Geosciences Union (EGU), 2012-03-22) Guimberteau, Matthieu; Drapeau, Guillaume; Ronchail, Josyane; Sultan, Benjamin; Polcher, Jan; Martinez, Jean-Michel; Prigent, Catherine; Guyot, Jean-Loup; Cochonneau, Gérard; Espinoza, Jhan Carlo; Filizola, N.; Fraizy, P.; Lavado, W.; De Oliveira, E.; Pombosa, R.; Noriega, L.; Vauchel, P.The aim of this study is to evaluate the ability of the ORCHIDEE land surface model to simulate streamflows over each sub-basin of the Amazon River basin. For this purpose, simulations are performed with a routing module including the influence of floodplains and swamps on river discharge and validated against on-site hydrological measurements collected within the HYBAM observatory over the 1980–2000 period. When forced by the NCC global meteorological dataset, the initial version of ORCHIDEE shows discrepancies with ORE HYBAM measurements with underestimation by 15 % of the annual mean streamflow at Obidos hydrological station. Consequently, several improvements are incrementally added to the initial simulation in order to reduce those discrepancies. First, values of NCC precipitation are substituted by ORE HYBAM daily in-situ rainfall observations from the meteorological services of Amazonian countries, interpolated over the basin. It highly improves the simulated streamflow over the northern and western parts of the basin, whereas streamflow over southern regions becomes overestimated, probably due to the extension of rainy spots that may be exaggerated by our interpolation method, or to an underestimation of simulated evapotranspiration when compared to flux tower measurements. Second, the initial map of maximal fractions of floodplains and swamps which largely underestimates floodplains areas over the main stem of the Amazon River and over the region of Llanos de Moxos in Bolivia, is substituted by a new one with a better agreement with different estimates over the basin. Simulated monthly water height is consequently better represented in ORCHIDEE when compared to Topex/Poseidon measurements over the main stem of the Amazon. Finally, a calibration of the time constant of the floodplain reservoir is performed to adjust the mean simulated seasonal peak flow at Obidos in agreement with the observations.Item Open Access Las diversas facetas de El Niño y sus efectos en la costa del Perú(Institut de Recherche pour l'Développement (IRD), 2014) Dewitte, B; Takahashi, Ken; Goubanova, K.; Montecinos, Aldo; Mosquera Vásquez, Kobi Alberto; Illig, S.; Montes Torres, Ivonne; Paulmier, A.; Garçon, V.; Purca, S.; Flores, R.; Bourrel, L.; Rau, P.; Labat, D.; Lavado, W.; Espinoza, Jhan CarloEl fenómeno El Niño es el modo dominante de la variabilidad interanual en el Océano Pacífico, resultando de un proceso de interacción entre el océano y la atmósfera en el Pacífico Tropical. Las últimas investigaciones demuestran que existen varias facetas de este fenómeno que varían según las modalidades de interacción entre el océano y la atmosfera así como sus ubicaciones. Existen por lo menos dos tipos de El Niño, con expresiones diferentes sobre la Temperatura Superficial del Mar en el Pacifico Tropical y en la costa de Perú: uno que se desarrolla en el Pacifico Central (tiende a estar asociado a condiciones oceánicas más frías que favorecen el estado árido de la costa peruana y condiciones oceánicas hypóxicas), y otro que se desarrolla en el Pacifico Este (que transforma la costa peruana en una "típica" zona tropical, caracterizada por aguas costeras calientes y oxigenadas, y una lluvia intensa). Hoy en día, los esfuerzos de investigación para entender los mecanismos involucrados en los diferentes tipos de El Niño han sido reforzados, dado que, en las últimas décadas, se ha incrementado la frecuencia de ocurrencia de estos eventos en el Pacifico Central, sugiriéndose que podría ser una consecuencia del cambio climático. El perfeccionamiento de los modelos regionales acoplados tanto océano - atmosfera como océano - biogeoquímico, tiene como objetivo mejorar la comprensión de la vulnerabilidad de la biósfera peruana al cambio climático y proponer un paradigma que represente la bimodalidad de la variabilidad interanual en el Pacifico Tropical.