Affiner votre recherche
Résultats 1-10 de 4,114
Temporal Analysis and Forecast of Surface Air Temperature: case study in Colombia
2022
Romero Leiton, Jhoana Patricia | Torres, Diego | Romero, Manuel
In this work, we study the short-term dynamics of the Surface Air Temperature (SAT) using data obtained from a meteorological station in Bogotá from 2009 to 2019 and using time series. The data that we used correspond to the monthly mean of the historical registers of SAT and three pollutants. A descriptive analysis of the data follows. Then, some predictions are obtained from two different approaches: (i) a univariate analysis of SAT through a SARIMA model, which shows a good fit; and (ii) a multivariate analysis of SAT and pollutants using a SVAR model. Suitable transformations were first applied on the original dataset to work with stationary time series. Subsequently, A SARIMA model and a VAR(2) with its associated SVAR model are estimated. Furthermore, we obtain one-year forecasts for the logarithm of SAT in both models. Our forecasts simulate the natural fluctuation of SAT, presenting peaks and valleys in months when SAT is high and low, respectively. The SVAR model allows us to identify certain shocks that affect the instant relationships among variables. These relations were studied by the impulse-response function and the VAR model variance decomposition. Although the statistical methods used in this study are classical, they continue being widely used in the environmental field, presenting god fits, and the results obtained in this study are consistent with environmental theories.
Afficher plus [+] Moins [-]PCBs [polychlorinated biphenyls], dioxins and furans in hooded merganser (Lophodytes cucullatus), common merganser (Mergus merganser) and mink (Mustela vison) collected along the St. Maurice River near La Tuque, Quebec.
1996
Champoux L.
The interaction of So2 and root-knot nematode on tomato.
1993
Khan M.R. | Khan M.W.
Etude prospective d' implantation de stations de mesures dans les Vosges. 1. Organisation, realisations. 2. Quelques resultats sur l' acidite des pluies en Lorraine. 3. La circulation atmospherique et la repartition des polluants dans le Massif Vosgien. 4. Premiers resultats, interpretation, hypotheses [deperissement des forets].
1985
Thuillier Anziani C. | Frecault R. | Roussel I. | Livertoux M.H.
Charges critiques pour la vegetation.
1993
Thimonier A. | Dupouey J.L.
Deperissement des forets et pollution atmospherique: ce que nous avons appris (Programme DEFORPA 1984-1991).
1992
Landmann G.
Les modifications chimiques de l' atmosphere et leurs effets sur l' environnement.
1988
Megie G.
Predisposition of trees by air pollutants to low temperatures and moisture stress.
1995
Chappelka A.H. | Freer Smith P.H.
Protocole d' etude de la retombee de polluants metalliques dans le milieu marin dans le cadre du programe ATMOS de la Commission de Paris.
1994
Le Bihan A. | Cabon J.Y. | Tymen G.
Elimination de l' ammoniac sur divers adsorbants: charbons actifs, tourbe et boues de station d' epuration.
1994
Samanni Vaute L. | Fanlo J.L. | Le Cloirec P.
