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Accueil du site → Doctorat → Royaume-Uni → 1994 → Modelling the hydrological impacts of climatic change on a semi-arid region

University of Newcastle upon Tyne (1994)

Modelling the hydrological impacts of climatic change on a semi-arid region

Medeiros, Yvonilde D P

Titre : Modelling the hydrological impacts of climatic change on a semi-arid region.

Auteur : Medeiros, Yvonilde D P

Université de soutenance : University of Newcastle upon Tyne

Grade : Doctor of Philosophy (Ph.D.) : 1994

Global climate change may be expected to occur within the next few decades. This hypothesis is based on the increase in atmosphere CO2 and other greenhouse gases. These increases will likely have different degrees of effects on the water resources in different places.The thesis focuses on the sensitivity of runoff and soil moisture to the climate change in the semi-arid region of north-east of Brazil (NEB). Climatic scenarios, based on the results yielded by the General Circulation Models (GCMs), were used to translate the potential changes in temperature and precipitation for the Northeast of Brazil into runoff and soil moisture predictions.Two stochastic rainfall models were investigated to simulate the daily rainfall series. One model was the Neyman-Scott Rectangular Pulses model based on point process cluster theory (Rodriguez-Iturbe et al., 1987 ; Cowpertwait, 1991). The other was a Markov chain model as proposed by Stern and Coe (1982). Although the two models presented a good fit to the historical rainfall series, the Neyman-Scott model was found to be more appropriate for the intended application.A rainfall-runoff conceptual model, MODHAC (Lanna and Schwarzbach, 1989), was used to simulate the runoff response to the variations in evaporation and precipitation. Investigations were carried out into the ability of probability distribution functions to reproduce the spatial distribution of infiltration capacity over the semiarid catchments. The triangular and lognormal distributions were tested and they produced quite similar hydrographs. The lognormal distribution was selected to simulate the runoff.Climatic change simulations were performed using the model parameters validated for the present conditions. The present and future conditions were derived from the GCM data under both the stable conditions - 1xCO2 and 2xCO2 concentrations in the atmosphere. Reasonable predictions of the changes in catchment runoff and soil moisture were obtained.

Mots clés : Hydrology & limnology Hydrology Meteorology Climatology Hydrology

Annonce : EThOS (UK)

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