In search of colonial El Niño events and a brief history of meteorology in Ecuador

International audienceThis study shows a brief overview of the development of meteorology in Ecuador from historical documentation of climatic events in the Colonial era through to modern data collection. In the colonial era (16th century-1824), historical documents of rogation ceremonies and municipal proceedings, from the Quito area, provide a rich source of climate information, including El Niño events. Our preliminary findings show that very few of the historically documented catastrophes and other marked environmental events in Quito match known El Niño episodes. Independently, the first meteorological data was collected in Ecuador (beginning with La Condamine in 1738), followed by the earliest attempts to build a national meteorological network in the 1860's, linked closely to President Gabriel García Moreno and the Jesuits. The 1925 El Niño phenomenon was the first important meteorological episode recorded with scientific instrumentation in Ecuador, with newspapers providing complementary archives about the extreme impact of this event

L'arbre fontaine

Dans certaines régions montagneuses régulièrement ventées, soumises à un climat océanique comme au Chili, en Afrique du Sud ou au Cap-Vert, une mer de brouillard règne en quasi permanence. Ces conditions météorologiques très singulières permettent à la végétation de prospérer malgré de faibles pluies. Arbres et arbustes captent l'eau des brouillards et des bruines, donnant naissance à de véritables forêts dites nébuleuses. Ces fontaines végétales sont exploitées par l'homme depuis la nuit des temps pour récupérer de l'eau potable et développer une vie agricole. Véritable don des dieux, l'arbre fontaine a parfois été élevé au rang d'arbre sacré comme dans l'île de Hierro aux Canaries, point de départ de la recherche des auteurs de cet article. (Résumé d'auteur

Water recovery from dew

International audienceThe recovery of clean water from dew has remained a longstanding challenge in many places all around the world. It is currently believed that the ancient Greeks succeeded in recovering atmospheric water vapour on a scale large enough to supply water to the city of Theodosia (presently Feodosia, Crimea, Ukraine). Several attempts were made in the early 20th Cent. to build artificial dew-catching constructions which were subsequently abandoned because of their low yield. The idea of dew collection is revised in the light of recent investigations of the basic physical phenomena involved in the formation of dew. A model for calculating condensation rates on real dew condensers is proposed. Some suggestions for the " ideal " condenser are formulated

Correlation between SERS of Pyridine and Electrochemical Response of Silver Electrodes in Halide-Free Alkaline Solutions

Surface-enhanced Raman scattering (SERS) of pyridine (Py) on Ag electrodes in alkaline solutions free of halide ions was obtained at 25°C as a function of the applied potential. The Ag surface was activated for SERS through repetitive oxidation-reduction cycles (ORC), the effect being dependent on the electrochemical electrode history. The SERS effect was correlated to the activation for the hydrogen evolution reaction (HER), which can be obtained by means of potentiodynamic as well as potentiostatic procedures. The maximum SERS activity was achieved at potentials near the potential of zero charge (pzc) of polycrystalline Ag and appeared to be related to the maximum observed in the roughness factor vs potential curve. These results can be interpreted through the formation of a new uniform globular overlayer structure on the electroreduced Ag surface, which apparently exhibits a certain degree of preferred crystallographic orientation. Three well-defined potential regions can be distinguished for the complex competitive interactions between H2O, OH- ion, and Py with the new Ag electrode surface.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Chemical composition of cloud water in the puerto rican tropical trade wind cumuli

As part of the Rain In Cumulus over the Ocean Experiment (RICO) and the Puerto Rico Aerosol and Cloud Study (PRACS), cloud water was collected at East Peak (EP) in Puerto Rico. The main objective of this study was to determine the concentrations of water-soluble species (Cl-, NO3 -, SO4 2-, NH4 +, Ca 2+, H+, Mg2+, K+, and Na +) in water samples taken from clouds influenced by tropical trade winds. The most abundant inorganic species were Na+ (average 465 μeq l-1) and Cl- (434 μeq l-1), followed by Mg2+ (105 μeq l-1), SO4 2- (61 μeq l-1), and NO3 - (25 μeq l -1). High concentrations of nss-SO4 2 (28 μeq l-1), NO3 - (86 μeq l-1), and H+ (14.5 μeq l-1) were measured with a shift in air masses origin from the North Atlantic to North American continent, which reflected a strong anthropogenic influence on cloud chemistry at EP. Long-range transport of particles and acid gases seems to be the factor responsible for fluctuations in concentrations and pH of cloud water at East Peak. When under trade wind influences the liquid phase concentrations of all inorganic substances were similar to those found in clouds in other clean maritime environments. © 2008 Springer Science+Business Media B.V

Correlation between SERS of Pyridine and Electrochemical Response of Silver Electrodes in Halide-Free Alkaline Solutions

Surface-enhanced Raman scattering (SERS) of pyridine (Py) on Ag electrodes in alkaline solutions free of halide ions was obtained at 25°C as a function of the applied potential. The Ag surface was activated for SERS through repetitive oxidation-reduction cycles (ORC), the effect being dependent on the electrochemical electrode history. The SERS effect was correlated to the activation for the hydrogen evolution reaction (HER), which can be obtained by means of potentiodynamic as well as potentiostatic procedures. The maximum SERS activity was achieved at potentials near the potential of zero charge (pzc) of polycrystalline Ag and appeared to be related to the maximum observed in the roughness factor vs potential curve. These results can be interpreted through the formation of a new uniform globular overlayer structure on the electroreduced Ag surface, which apparently exhibits a certain degree of preferred crystallographic orientation. Three well-defined potential regions can be distinguished for the complex competitive interactions between H2O, OH- ion, and Py with the new Ag electrode surface.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada