Browsing by Author "Moreno-Ramírez, H. A. (Hernán Alonso)"

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    PublicationOpen Access
    Annual and diurnal cycles of the inverse relation between plant transpiration and carbon sequestration
    (2014-05-09) Moreno-Ramírez, H. A. (Hernán Alonso)
    El conocimiento de los ciclos biogeoquímicos y, en especial, de los balances de carbono es clave para la validación de los modelos de cambio global para el presente y el futuro cercano. Como consecuencia, en el mundo se estudian las fuentes y los sumideros de carbono. Uno de esos sumideros es la vegetación del planeta, que involucra los procesos de respiración y fotosíntesis y cuyo comportamiento se empieza a estudiar. Las tasas de captura del carbono están muy ligadas a la transpiración mediante un proceso de difusión molecular en los estomas, que puede registrarse por un sistema micrometeorológico de eddy covarianza. Este artículo explora los ciclos anuales y diurnos de los flujos netos de CO2 y calor latente de seis ecosistemas diferentes. Se desarrollan diversos análisis de escala temporal, basados en la física de la transpiración, y se halla una relación cuasilineal entre los flujos netos de calor latente y CO2, más fuerte en las áreas con mayor cobertura vegetal. La temporada del monzón norteamericano incrementa la captura de carbono y la relación entre la evapotranspiración y el intercambio de gas carbónico se mantiene en las diferentes escalas temporales analizadas (horas, días, meses).
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    PublicationOpen Access
    La lluvia y los deslizamientos de tierra en Antioquia: análisis de su ocurrencia en las escalas interanual, intraanual y diaria
    (2014-05-07) Moreno-Ramírez, H. A. (Hernán Alonso); Vélez-Otálvaro, M. V. (María Victoria); Montoya, J. D. (Juan David); Rhenals-Garrido, R. L. (Remberto Luis)
    Relationship between rain and reported landslides in the department of Antioquia for the period of 1929 to 1999 is studied. The georeference of 405 landslides possibly produced by rain is made, on the region of study. The analysis of the occurrence of landslides during the warm and cold phases of ENSO phenomenon (El Niño Southern Oscillation) and the behavior of the intra-annual cycle are described. La Niña, on interannual scale, and the two rainiest periods in Andean zone, on intra-annual scale, contribute to increase the number of landslides per year. Analysis of precipitation data associated with historical landslide events in Antioquia has resulted in the identification of precipitation thresholds for the initiation of landslides and the possible combinations of preceding accumulated rain are described. The data indicated that the cumulative precipitation (15 days or more) influences the amount of subsequent 3-day precipitation that is needed to initiate ground movement. This study constitutes a first intend toward rain modeling and its influence on landslides occurrence which can help authorities on disasters prevention to declare states of emergency by conditions of threshold exceed. The analysis must be complemented having into account geotechnical, morphological, hydraulics, and anthropogenic conditions own to each place to have an integral view of the landslide phenomenon.
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    PublicationOpen Access
    Modelamiento estocástico en la determinación de la oferta hídrica del río Source Matelas (Haití): aplicación al predimensionamiento de un embalse
    (2014-05-07) Giraldo, L. P. (Lía Patricia); Pérez, D. P. (Diana Patricia); Moreno-Ramírez, H. A. (Hernán Alonso); Ruiz-Carrascal, C. D. (Carlos Daniel)
    Source Matelas, located in the West State, Republic of Haiti, is a town with scarce economical resources and low quality of life, mainly because of the absence almost total of water. In this work we give a first approximation to a water reservoir pre-feasibility study, related to water supply quantification of the region, by means of hydrological methods to estimate unknown information. Long term components of the hydrological balance are calculated and daily mean yield that serves the model of reservoir simulation is estimated. The mean runoff calculated for the Source Matelas River is 0.026 m3/s. Based on reservoir modeling, volume needed to supply different percentages of the mean runoff is calculated. Therefore, it can be seen that population water demand will be supplied totally if a reservoir of 212000 m3 volume is constructed.