No presente trabalho são analisadas as séries históricas da temperatura do ar e da precipitação observada na Ilha Terceira desde o início da observação meteorológica regular no Arquipélago dos Açores. O trabalho teve como objectivo a caracterização da variação inter-anual das duas variáveis estudadas bem como a pesquisa de eventuais indicadores de alterações climáticas observáveis na localização do Arquipélago dos Açores. Foram analisadas as séries da temperatura e precipitação desde o ano de 1874 até ao ano 2000 as quais revelam aspectos singulares, nomeadamente, no que diz respeito à tendência e sazonalidade. Com base na sua interpretação é sugerida uma teoria justificativa do comportamento observado.

An intense storm, including strong winds, a dust storm, ‘blood rain’ and heavy rains affected the Canary Archipelago between 5 and 10 January 1999, producing damage valued at 156 million euros. The present paper analyses the weather conditions and sedimentological features of the dust. The resulting data provide a possible explanation of palaeoclimatic conditions essential for the stabilization of sand dunes in the eastern parts of the Canary Islands.

L'etude détaillée des précipitation, surtout celles de nature torrentielle, est essentielle pour compendre l'activité sporadique des cours d'eau qui sillonenent les archipels de la Macaronesia, ainsí que leurs répercussions torrentiales. Cet article analyse les précipitations à l'échelle jounaliére de quatre îles: Terceira (Les Açores), Madére (Madére), Tenerife (Les Canaries) et Santiago (Le Cap Vert), de 1980 à 2004. Les résultats montrent que la latitude, à l'échelle régionale, ains que l'orientation el l'altitude, à l'echelle local, sont les facteurs géographiques expliquant les différences spatiales et d'intensité des pluies dans chacune des îles, alores que la circulation atmosphérique justifie leur importante variation de volume et leur distribuition temporaire d'une île a l'autre .
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The datailed study of the rainfalls, especially f the torrential ones, is essential to understand the sporadir activity of the water courses that furrow the archipelagoes of the Macaronesia and its territorial repercurssions. In this article the rain of four islands is analyzed to daily scale: Terceira (Azores), Madeira (Madeira), Tenerife (Canaries) and Santiago (Cape Verde), from 1980 to 2004. The results show clearly that the factors that explain the spatial differences and of intensity of the rain in each of the islands, whereas the atmospheric movements justifies the the volumes and temporary distribution of rainfall varies notably form one island to another.

The aim of this paper is to state the impact of two sea storm patterns along the coast of Tenerife. They are both linked to two specific atmospheric conditions – one to swell events such as the one that took place between 26 and 30 December 1998, and the other one to sea waves such as those from 7 to 8 January 1999. Buoys and Wana models provided by Puertos del Estado (General Direction of Coasts) were used to obtain scale and directional swell data from 1985 to 2003. Analysis of average annual Hm, Hmax, Tp, wave length, wave direction and wind speed and direction values were used to characterise storm conditions. A first approach refers 98 possible storm events. Then, two storms are chosen and the sharp hourly variations of swell parameters are studied during their lifespan. The interest of such study lies in the fact that over half the perimeter of the island is densely populated and the urban planning system should consider the risk from storms.

O clima do Arquipélago dos Açores é, no seu conjunto, ditado pela sua localização geográfica no contexto da circulação global atmosférica e oceânica e pela influência da mass aquática da qual emerge. No presente trabalho é feita uma caracterização à escala da bacia do Atlântico Norte dos mecanismos que, ao longo do ano, determinan o clima do arquipélago.

The aim of this work is to obtain the effective radius as a function of other aerosol retrievals from the Moderate-Resolution Imaging Spectroradiometer (MODIS) (Ångstrom parameter, aerosol optical depth, backscattering ratio,...) which can be obtained by other remote sensors like Advanced Very High Resolution Radiometer (AVHRR) with a very long time series. In order to reduce the number of MODIS useful variables a Factorial Analysis by Principal Component has been applied. With this technique we have obtained three factors, which reduce the aerosol parameters from 28 to 9. Using these 9 parameters it has been applied Lineal Multivariate Analysis techniques to find a combination of independent variables that better evaluate the aerosol effective radius. The regression model obtained explains the 99.6% of the variation in this parameter. The MODIS/Terra level-2 aerosol products over ocean has been studied for 2002-2003 in a grid centred in the Canary Islands (26ºN-31ºN, 13ºW-19ºW). It has been found that these correlations are independent of the aerosol load for any situation.

In this work we have studied the impact of the mineral dust over the daily UV erythemal exposure (EUV). To characterize the load of mineral dust the TOMS AI product has been used, and the UV erythemal exposure has been calculated by TOMS instrument (TOMS EUV), on board Earth Probes, and by Brewer instruments located in ground based stations (BEUV). EUV variations have been evaluated under different aerosol load conditions in stations frequently affected by the two main mineral dust sources (Gobi and Sahara-Sahel regions). The ground stations are located in Japan (3 stations) and in the Canary Islands (1 station), and the studied period encompass from 1997 to 2000. There is not a similar pattern of variations of the TOMS EUV levels with the TOMS AI between the all stations. In addition, the behaviour observed for the Atlantics station is different to the measured for the Japanese observatories

El mayor desierto del planeta, el Sáhara, constituye un manantial de aire cálido y seco y, a su vez, de grandes cantidades de material particulado litogénico. Su cercanía a Canarias implica una enorme influencia en el clima de toda la región y los cuantiosos aportes de polvo tienen importantes repercusiones no sólo sobre el medio natural, sino también sobre aspectos socioeconómicos de las Islas. Ya comienza a demostrarse su incidencia en algunas enfermedades y las altas temperaturas que acompañan a estas situaciones atmosféricas afectan a cultivos, incendios forestales, etc. Aquí mostramos la influencia del aerosol mineral de origen sahariano en Canarias. Este trabajo se enmarca en un grupo de líneas de investigación que estudian la importancia que la distribución del aerosol mineral tiene sobre el clima y el medio ambiente, siendo actualmente uno de los temas de mayor relevancia en investigaciones de disciplinas como la Climatología o la Oceanografía

El objetivo de este trabajo es abordar la caracterización, origen, evolución y funcionamiento de las áreas sin drenaje organizado, o con él muy incipiente, de las islas volcánicas de Flores y San Miguel (Azores), Madeira (Madeira), Tenerife (Canarias) y Santiago (Cabo Verde). Éstas cuentam con una superficie total de 4.671 km2 correspondiendo el 12% de ella a sectores sin avenamiento concentrado. En los ámbitos volcánicos , sobre todo si son reciente, el arreismo no está siempre determinado por condiciones térmicas y de evaporación, pues la mayor o menor juventud del sustrato geológico y la porosidad y permeabilidad inicial de los materiales eruptivos inhiben en grado variable la escorrentía superficial. Estos factores estruturales explicam el comportamiento de las áres arreicas ante las precipitationes. En estas isla, la intensidad y la concentration da las lluvias , muy acentuadas por la latitude del relieve, no suelen estrañar riesgos en dichas áreas, mientras que el resto del território son susceptibles de derivar en crescidas eventualmente catastróficas. De ahí la importancia de estas áreas en el conocimiento de la distribuición espacial de los impactos causados por lluvias torrenciales.
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The aim of this work is to approach the characterization, origin, evaluation and functioning of the areas wihout organized drainage, or with a very incipient on, of the volcanic islands of Flowers and San Miguel (Azores), Madeira (Madeira), Tenerife (Canaries) and Santiago (Cape Vert). These possess a total surface of 4.671 km2 corresponding 12% from it to sectors without concentrated drainage. In the volcanic areas, especially if they are recent, the areism is not always determined by thermal and evaporation conditions since the major or minor youth of the geological substratum and the porosity and initial permeability of the eruptive materials inhibit, in a variable degree, the superficial flow. These structurak factors explain the behaviour of the areism areas in rainfall periods. The intensity and the concentration of the rains, very accentuated by the altitude of the relief, usually do not represent risks in the above mentioned areas, whereas in the rest of the territory they are capable of deriving in eventually catastrophic floods. This is the reason of the importance of these areas om the knowladge of the spatial distribution of the impacts caused by torrential rains.

En este artículo se realiza un análisis comparativo de las precipitaciones diarias de las islas de Terceira (Azores), Madeira (Madeira), Tenerife (Canarias) y Santiago (Cabo Verde) con el fin de caracterizar la pluviosidad en los cuatro archipiélagos de la Macaronesia. Se examinan así mismo los episodios diarios de lluvias más intensas, su duración y frecuencia, para determinar la vulnerabilidad de esos archipiélagos ante fenómenos meteorológicos extremos de ese tipo.
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In this article there is realized a comparative analysis of the daily rainfalls of the islands of Terceira, Madeira, Tenerife and Santiago in order to characterize the rainfall in the four archipelagoes of the Macaronesia. There are examined likewise the daily episodes of the most intense rains, its duration and frequency, to determine the vulnerability of these archipelagoes before meteorological extreme phenomena of this type.

In small volcanic islands the local scale climate is influenced by the regional scale climate and by the orography and orientation of air masses movement over the islands. A model was developed in a GIS environment to generate local scale climate variables from those observed at the synoptic scale, from coastal weather stations. An advective submodel, based on the Foehn effect and assuming the conservation of mass and energy, computes local scale air temperature, relative humidity, clouds occurrence and precipitation. A radiative submodel, using information generated by the advective submodel, computes local scale global radiation. A rotational terrain model allows that computations be performed according to the direction of wind. Because the model works within a GIS, results concern the spatial distribution of all climatic variables on the island territory. Results of the validation of temperature, relative humidity, global radiation and rainfall are presented. For agro-meteorological purposes, an application of generated data to perform the sequential water balance is also analysed by comparing results from computations using simulated and observed data at a control weather station located at medium altitude. Results support assumptions utilised in the model and the further use of generated local climate fields for water management and environmental studies in small island environments

The Sahara, the largest desert in the world is a source of dry hot air and also dust. Its position, very close to the Canary archipelago has a hard influence on the climate of this area because of the inexhaustible supply of dust and the high temperatures have adverse effects on the environments and socioeconomic aspects such as health, forest fires frequency, crops. This paper examines this topic quantitatively.