Browsing by Author "Lavado Casimiro, Waldo Sven"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
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 Restricted Climate control on silicate weathering and physical erosion rates in young orogenic belts: Case study along a runoff gradient in Pacific and Amazonian Andean basins based on SNO-HYBAM Monitoring Program data(EGU General Assembly, 2017-04) Moquet, Jean Sébastien; Guyot, Jean-Loup; Viers, Jérôme; Crave, Alain; Morera Julca, Sergio Byron; Rau, Pedro; Armijos Cardenas, Elisa Natalia; Lagane, Christelle; Lavado Casimiro, Waldo Sven; Pombosa, Rodrigo; Fraizy, Pascal; Santini, William; Timouk, Franck; Vauchel, Philippe; Martinez, Jean-MichelAt the global scale and on geological time scales, mechanical erosion and chemical weathering budgets are linked. Together, these processes contribute to the formation and the degradation of the Earth's critical zone and to the biogeochemical cycles of elements. In young orogenic belts, climate and tectonic subsidence control together the rate of these matter balance budget and their relationships. The climate gradient observed along the Andean basin in both the Pacific and the Atlantic slopes offers the opportunity to explore the role of the climate variability on the erosion and weathering budgets and on their reciprocal relationships. Based on the SNO-HYBAM Monitoring Program database (Geodynamical, hydrological and Biogeochemical control of erosion/weathering and material transport in the Amazon, Orinoco and Congo basins), we explore the relationship between climate, the lithology, silicate weathering rates and physical erosion rates along a runoff gradient in Andean basins of the Amazon River (13 gauging stations) and Pacific drainage rivers (5 gauging stations). No homogenous relationship between erosion rates (E) and chemical weathering rate (W) is observed over the monitored basins. Only the volcanic basins respond to a global relationship defined in the literature while the other basins budget may depend on anthropogenic interferences on erosion/sedimentation budget, a lithology dependence of the W-E relationship parameters or/and on the existence of a threshold in this relationship. The results presented here contribute to better understanding the role of mountains belt formation in the biogeochemical cycles and in particular in the long-term carbon cycle.Your presentation type preference.Item Restricted Trends in rainfall and temperature in the Peruvian Amazon–Andes basin over the last 40 years (1965–2007)(Wiley, 2013-09-30) Lavado Casimiro, Waldo Sven; Labat, David; Ronchail, Josyane; Espinoza, Jhan Carlo; Guyot, Jean LoupThe hydroclimatology of the Peruvian Amazon-Andes basin (PAB) which surface corresponds to 7 % of the Amazon basin is still poorly documented. We propose here an extended and original analysis of the temporal evolution of monthly rainfall, mean temperature (Tmean), maximum temperature (Tmax), and minimum temperature (Tmin) time series over two Peruvian Amazon-Andes basins (Huallaga and Ucayali) over the last forty years. This analysis is based on a new and more complete database that includes 77 weather stations over the 1965-2007 period and we focus our attention on both annual and seasonal meteorological time series. A positive significant trend in mean temperature of 0.09°C per decade is detected over the region with similar values in the Andes and Rainforest when considering average data. Though, a high percentage of stations with significant Tmean positive trends are located over the Andes region. Finally, changes in the mean values occurred earlier in Tmax (during the 1970s) than in Tmin (during the 1980s). In the PAB, there is neither trend nor mean-change in rainfall, during the 1965-2007 period. However, annual, summer and autumn rainfall in the southern Andes presents an important interannual variability that is associated with the sea surface temperature (SST) in the tropical Atlantic Ocean while there are limited relationships between rainfall and ENSO events. On the contrary, the interannual temperature variability is mainly related to ENSO events.