Santa Cruz de Tenerife, Spain
Santa Cruz de Tenerife, Spain

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Rodriguez S.,Izana Atmospheric Research Center | Alastuey A.,CSIC - Institute of Environmental Assessment And Water Research | Alonso-Perez S.,Izana Atmospheric Research Center | Alonso-Perez S.,CSIC - Institute of Environmental Assessment And Water Research | And 7 more authors.
Atmospheric Chemistry and Physics | Year: 2011

An analysis of chemical composition data of particulate matter samples (TSP, PM10 and PM2.5) collected from 2002 to 2008 in the North Atlantic free troposphere at the Izaña Global Atmospheric Watch (GAW) observatory (Tenerife, Canary Islands) shows that desert dust is very frequently mixed with particulate pollutants in the Saharan Air Layer (SAL). The study of this data set with Median Concentrations At Receptor (MCAR) plots allowed the identification of the potential source regions of the dust and particulate pollutants. Areas located at the south of the southern slope of the Atlas mountains emerge as the most frequent source of the soil desert dust advected to the northern edge of the SAL in summer. Industrial emissions occurring in Northern Algeria, Eastern Algeria, Tunisia and the Atlantic coast of Morocco appear as the most important source of the nitrate, ammonium and a fraction of sulphate (at least 60 % of the sulphate <10 ?1/4m transported from some regions) observed in the SAL. These emissions are mostly linked to crude oil refineries, phosphate-based fertilizer industry and power plants. Although desert dust emissions appear as the most frequent source of the phosphorous observed in the SAL, high P concentrations are observed when the SAL is affected by emissions from open mines of phosphate and phosphate based fertilizer industry. The results also show that a significant fraction of the sulphate (up to 90 % of sulphate <10 ?1/4m transported from some regions) observed in the SAL may be influenced by soil emissions of evaporite minerals in well defined regions where dry saline lakes (chotts) are present. These interpretations of the MCAR plots are consistent with the results obtained with the Positive Matrix Factorization (PMF2) receptor modelling. The results of this study show that North African industrial pollutants may be mixed with desert dust and exported to the North Atlantic in the Saharan Air Layer. © 2011 Author(s).

Cuevas E.,Izana Atmospheric Research Center | Gonzalez Y.,Izana Atmospheric Research Center | Rodriguez S.,Izana Atmospheric Research Center | Guerra J.C.,University of La Laguna | And 6 more authors.
Atmospheric Chemistry and Physics | Year: 2013

An analysis of the 22-yr ozone (O3) series (1988-2009) at the subtropical high mountain Izaña∼station (IZO; 2373 m a.s.l.), representative of free troposphere (FT) conditions, is presented. Diurnal and seasonal O3 variations as well as the O3 trend (0.19 ± 0.05 % yr-1 or 0.09 ppbv yr-1), are assessed. A climatology of O 3 transport pathways using backward trajectories shows that higher O3 values are associated with air masses travelling above 4 km altitude from North America and North Atlantic Ocean, while low O3 is transported from the Saharan continental boundary layer (CBL). O3 data have been compared with PM10, 210Pb, 7Be, potential vorticity (PV) and carbon monoxide (CO). A clear negative logarithmic relationship was observed between PM10 and surface O3 for all seasons. A similar relationship was found between O3 and 210Pb. The highest daily O3 values (90th percentile) are observed in spring and in the first half of summer time. A positive correlation between O3 and PV, and between O 3 and 7Be is found throughout the year, indicating that relatively high surface O3 values at IZO originate from the middle and upper troposphere. We find a good correlation between O3 and CO in winter, supporting the hypothesis of long-range transport of photochemically generated O3 from North America. Aged air masses, in combination with sporadic inputs from the upper troposphere, are observed in spring, summer and autumn. In summer time high O3 values seem to be the result of stratosphere-to-troposphere (STT) exchange processes in regions neighbouring the Canary Islands. Since 1995-1996, the North Atlantic Oscillation has changed from a predominantly high positive phase to alternating between negative, neutral or positive phases. This change results in an increased flow of the westerlies in the mid-latitude and subtropical North Atlantic, thus favouring the transport of O3 and its precursors from North America, and a higher frequency of storms over North Atlantic, with a likely higher incidence of STT processes in mid-latitudes. These processes lead to an increase of tropospheric O3 in the subtropical North Atlantic region after 1996 that has been reflected in surface O3 records at IZO. © 2013 Author(s).

Martin J.L.,Canary Islands Agency for Climate Change and Sustainable Development | Bethencourt J.,Canary Islands Agency for Climate Change and Sustainable Development | Cuevas-Agullo E.,Izana Atmospheric Research Center
Climatic Change | Year: 2012

Temperature variation is studied at different altitudes and orientation on the island of Tenerife, according to the trends in the mean, maximum and minimum at 21 meteorological stations. Reference series are obtained by sectors, along with a representative overall series for Tenerife, in which temperature shows a statistically significant growth trend of 0.09 ± 0.04°C/decade since 1944. Night-time temperatures have risen most (0.17°C ± 0.04°C/decade), while by day they have been more stable. Consequently, the diurnal temperature range between day and night has narrowed. By regions, warming has been much more intense in the high mountains than the other sectors below the inversion layer between 600 and 1,400 m altitude, and progressively milder towards the coast. The temperature rise on the windward (north-northeast) slopes is greater than on the leeward side and could be related to the increase in cloudiness on the northern side. The general warming of the island is less than in continental areas at between 24 and 44°N, being closer to the sea surface temperature in the same area. This is probably explained largely by the insular conditions. In fact warming is more evident in the high mountains (0.14 ± 0.07°C/decade), where the tempering effect of the ocean and the impact of changes in the stratocumulus is weaker, being similar to the mean continental values in the northern hemisphere. © 2012 Springer Science+Business Media B.V.

Dall'Osto M.,CSIC - Institute of Environmental Assessment And Water Research | Beddows D.C.S.,University of Birmingham | Pey J.,CSIC - Institute of Environmental Assessment And Water Research | Rodriguez S.,University of Huelva | And 5 more authors.
Atmospheric Chemistry and Physics | Year: 2012

Differential mobility particle sizer (DMPS) aerosol concentrations (N13-800) were collected over a one-year-period (2004) at an urban background site in Barcelona, North-Eastern Spain. Quantitative contributions to particle number concentrations of the nucleation (33-39%), Aitken (39-49%) and accumulation mode (18-22%) were estimated. We examined the source and time variability of atmospheric aerosol particles by using both K-means clustering and Positive Matrix Factorization (PMF) analysis. Performing clustering analysis on hourly size distributions, nine K-means DMPS clusters were identified and, by directional association, diurnal variation and relationship to meteorological and pollution variables, four typical aerosol size distribution scenarios were identified: traffic (69% of the time), dilution (15% of the time), summer background conditions (4% of the time) and regional pollution (12% of the time). According to the results of PMF, vehicle exhausts are estimated to contribute at least to 62-66% of the total particle number concentration, with a slightly higher proportion distributed towards the nucleation mode (34%) relative to the Aitken mode (28-32%). Photochemically induced nucleation particles make only a small contribution to the total particle number concentration (2-3% of the total), although only particles larger than 13 nm were considered in this study. Overall the combination of the two statistical methods is successful at separating components and quantifying relative contributions to the particle number population. © 2012 Author(s).

Redondas A.,Izana Atmospheric Research Center | Evans R.,National Oceanic and Atmospheric Administration | Stuebi R.,Federal Office of Meteorology and Climatology | Kohler U.,German Weather Service | Weber M.,University of Bremen
Atmospheric Chemistry and Physics | Year: 2014

The primary ground-based instruments used to report total column ozone (TOC) are Brewer and Dobson spectrophotometers in separate networks. These instruments make measurements of the UV irradiances, and through a well-defined process, a TOC value is produced. Inherent to the algorithm is the use of a laboratory-determined cross-section data set. We used five ozone cross-section data sets: three data sets that are based on measurements of Bass and Paur; one derived from Daumont, Brion and Malicet (DBM); and a new set determined by Institute of Experimental Physics (IUP), University of Bremen. The three Bass and Paur (1985) sets are as follows: quadratic temperature coefficients from the IGACO (a glossary is provided in Appendix A) web page (IGQ4), the Brewer network operational calibration set (BOp), and the set used by Bernhard et al. (2005) in the reanalysis of the Dobson absorption coefficient values (B05). The ozone absorption coefficients for Brewer and Dobson instruments are then calculated using the normal Brewer operative method, which is essentially the same as that used for Dobson instruments. Considering the standard TOC algorithm for the Brewer instruments and comparing to the Brewer standard operational calibration data set, using the slit functions for the individual instruments, we find the IUP data set changes the calculated TOC by -0.5%, the DBM data set changes the calculated TOC by -3.2%, and the IGQ4 data set at -45 °C changes the calculated TOC by +1.3%. Considering the standard algorithm for the Dobson instruments, and comparing to results using the official 1992 ozone absorption coefficients values and the single set of slit functions defined for all Dobson instruments, the calculated TOC changes by +1%, with little variation depending on which data set is used. We applied the changes to the European Dobson and Brewer reference instruments during the Izaña 2012 Absolute Calibration Campaign. With the application of a common Langley calibration and the IUP cross section, the differences between Brewer and Dobson data sets vanish, whereas using those of Bass and Paur and DBM produces differences of 1.5 and 2%, respectively. A study of the temperature dependence of these cross-section data sets is presented using the Arosa, Switzerland, total ozone record of 2003-2006, obtained from two Brewer-type instruments and one Dobson-type instrument, combined with the stratospheric ozone and temperature profiles from the Payerne soundings in the same period. The seasonal dependence of the differences between the results from the various instruments is greatly reduced with the application of temperature-dependent absorption coefficients, with the greatest reduction obtained using the IUP data set. © 2014 Author(s). CC Attribution 3.0 License.

Pey J.,CSIC - Institute of Environmental Assessment And Water Research | Alastuey A.,CSIC - Institute of Environmental Assessment And Water Research | Querol X.,CSIC - Institute of Environmental Assessment And Water Research | Rodriguez S.,Izana Atmospheric Research Center
Atmospheric Environment | Year: 2010

Different monitoring parameters (PM mass concentrations, number-size distribution, black carbon, gaseous pollutants, and chemical composition, among others) are currently used in air quality studies. Urban aerosols are the result of several sources and atmospheric processes, which suggests that a single monitoring technique is insufficient to quantitatively evaluate all of them.This study assesses the suitability of a number of monitoring techniques (PM mass concentrations, number and size distribution of ultra-fine particles, levels of gaseous pollutants, and a complete chemical characterization of PM10 and PM2.5) by examining the response of those techniques to the different emission sources and/or atmospheric processes affecting an urban Mediterranean area (Barcelona, NE Spain).The results of this work reveal that the PM mass, the number concentration and the chemical composition give different, but complementary, information. Whereas the mineral matter, a key atmospheric aerosol component across the Mediterranean, is not properly quantitatively assessed by measuring sub-micrometric particles, the monitoring of the number concentration is indispensable to interpret the origin of specific aerosol episodes. Furthermore, the chemical composition yields very relevant information to deduce the causes of specific pollution episodes.The number concentration of ultra-fine particles in urban areas is strongly dependent upon vehicle exhaust emissions, which may cause adverse health impacts. Moreover, urban Mediterranean environments are favourable to produce nucleation-mode particles (<20 nm) with photochemical origin. In those cases, these particles are expected to be of high solubility and consequently their toxicity may differ from that of traffic-generated ultra-fine particles. Thus, the use of a single monitoring parameter to evaluate the health effects seems to be not enough. © 2010 Elsevier Ltd.

Rodriguez S.,Izana Atmospheric Research Center | Alastuey A.,CSIC - Institute of Environmental Assessment And Water Research | Querol X.,CSIC - Institute of Environmental Assessment And Water Research
Aeolian Research | Year: 2012

Desert dust emitted and transported to distant regions influence on the climate, biogeochemistry and air quality of our planet. Long term (multi-decadal) measurements of aerosol dust with in situ characterization techniques are crucial for understanding the interactions of dust with the Earth system. We reviewed the programs which have been performing such long term dust monitoring. First long term observations started in the North Atlantic during the 1960s. Although dust programs rapidly expanded during the 1980s and 1990s, mostly across the Pacific and Atlantic oceans, only a few sites that have been active in the last 20-30. years continue operative nowadays. We reviewed the techniques that are available for in situ aerosol dust characterization. Techniques for long term measurement of mass concentration, size distribution, bulk composition, optical properties are nowadays available. Other techniques that are not regularly used in (or designed for) long term programs are also described; these may be incorporated into long term programs in specific periods (e.g. dust season on a year-to-year basis). Their implementation in long term programs allow us to study potential changes in the sources of some key minerals linked to changes in the strength and location of dust sources, and/or the mixing state of dust with pollutants related to the evolution of anthropogenic emissions. Given that some of these methods are not specifically designed for dust, some considerations should be addressed when the techniques are used for aerosol dust measurements. Accuracy, sources of errors, corrections and features of dust measurements are reviewed. © 2012 Elsevier B.V.

Alonso-Perez S.,Izana Atmospheric Research Center | Alonso-Perez S.,CSIC - Institute of Environmental Assessment And Water Research | Cuevas E.,Izana Atmospheric Research Center | Querol X.,CSIC - Institute of Environmental Assessment And Water Research
Meteorology and Atmospheric Physics | Year: 2011

Synoptic geopotential height anomalies patterns favouring African dust outbreaks into the marine boundary layer (MBL) of the subtropical Eastern North Atlantic Region (SENAR) were objectively identified. The proportion of the total variance explained by each of these patterns was also calculated. Dust intrusions into the MBL of the SENAR were identified using total suspended particles (TSP) data at a rural background station in Tenerife Island (El Rio station, ER). Geopotential height anomalies at 1,000, 850, 700 and 500 hPa, respectively, in days of African dust intrusion in the period 1998-2003 were grouped in monthly sets. Two different but complementary methods (K-means and Principal Components) were applied to daily geopotential height anomalies for each month and for each pressure level in case of African dust intrusion. Three principal geopotential height anomalies patterns were found. Type I consist on a high-pressure system over Europe that affects North Africa, occasionally giving rise to a ridge. The Canary Islands are in the south-west flank of this high-pressure system. This pattern is dominant throughout the whole year. Type II and type III patterns consist on a low located to the northeast and southeast of the Canary Islands, respectively, coupled with a high over the Mediterranean basin and/or North Africa. Two case analyses are presented, as well as a systematic validation of the meteorological pattern classification for all dust intrusions detected at ER station within the period 2004-2007. © 2011 Springer-Verlag.

Gonzalez Y.,Izana Atmospheric Research Center | Rodriguez S.,Izana Atmospheric Research Center
Atmospheric Research | Year: 2013

A study on the contribution of vehicle exhausts, ships and an oil refinery emission to the ambient air concentration of ultrafine particles (UFPs) is presented. It is based on a data set of particle number coarser than 2.5nm (N), black carbon (BC), gaseous pollutants (NOx, SO2, CO and O3), PM2.5 and PM10 measured from 2008 to 2010 in the ambient air of Santa Cruz de Tenerife City, where a previous study found an association between hospitalizations due to heart failure and exposure to UFPs in the ambient air. The observed relationship between N, BC and gaseous pollutants allowed segregating UFP concentrations in a set of components linked to each source. It was found that vehicle exhausts contribute to the background of UFPs, whereas high UFP episodes were due to the emissions of the refinery and ships. The concentration of UFP linked to vehicle exhaust emissions maximized in the morning (07:00-09:00 GMT, 5000-25,000cm-3=25th-75th percentile), whereas those linked to ship (15,000-45,000cm-3) and refinery (25,000-95,000cm-3) emissions maximized in the 10:00-17:00 GMT period due to the effects of meteorology and photochemistry. It was found that the UFP concentrations were more sensitive to the fresh emissions of the three sources than PM2.5, which was mostly linked to aged fine particles (0.1-1μm) of the urban background. BC was the better tracer of vehicle exhaust emissions. It was concluded that the simultaneous monitoring of UFP, BC and PM2.5 is a suitable strategy of tracing aerosol pollutants of different nature (fresh vs. aged) and from different sources. © 2012 Elsevier B.V.

Rodriguez-Franco J.J.,Izana Atmospheric Research Center | Cuevas E.,Izana Atmospheric Research Center
Journal of Geophysical Research: Atmospheres | Year: 2013

This study examines the structure of the subtropical tropopause region over Tenerife (the Canary Islands, Spain; 28°N, 16°W) based on a 20 year (1992-2011) ozonesonde data and European Center for Medium-Range Weather Forecasts ERA-Interim potential vorticity (PV) and zonal wind speed reanalysis. High-resolution vertical profiles allowed a detailed description of the subtropical tropopause break and the associated subtropical jet stream (STJ), where models fail to properly simulate the upper troposphere-lower stratosphere (UTLS). The subtropical UTLS is revealed as a complex atmospheric region with a thickness ∼8 km, which is examined through the analysis and evaluation of four different tropopause definitions: thermal (TT), cold point, ozone (OT), and dynamical (DT) tropopauses. A novel method to determine the DT based on the vertical gradient of Lait's modified PV is presented and the concept of a second DT has been introduced for the first time. Monthly climatologies of tropopause height and potential temperature are calculated for double and single tropopause events. The 14.3 km height level is used to differentiate between tropical and extratropical UTLS regimes, intimately linked to the position of the STJ. There is fairly good consistency between all the defined tropopauses under the double tropopause scheme, except in spring, when the OT is observed at lower levels due to frequent baroclinic instabilities in the upper troposphere. As concerns to single tropopause events, the same pattern is found from April to June, reflecting the influence of analogous processes during these months. In winter, altitude differences between OT, DT, and TT resulted from poleward STJ excursions forced by blocking systems over the North Atlantic. Analysis of the tropopause inversion layer showed distinctive features for tropical and midlatitude tropopauses. Key Points The subtropical tropopause region is thoroughly characterized Several PV values are possible to define an isentropic barrier in the subtropics Distinctive features for midlatitude and tropical tropopauses are revealed ©2013. American Geophysical Union. All Rights Reserved.

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