Columnar aerosol characterization over Scandinavia and Svalbard

An overview of sun photometer measurements of aerosol properties in Scandinavia and Svalbard was provided by Toledano et al. (2012) thanks to the collaborative effort of various research groups from different countries that maintain a number of observation sites in the European Arctic and sub-Arctic regions. The spatial coverage of this kind of data has remarkably improved in the last years, thanks, among other things, to projects carried out within the framework of the International Polar Year 2007-08. The data from a set of operational sun photometer sites belonging either to national or international measurement networks (AERONET, GAW-PFR) were evaluated. The direct sun observations provided spectral aerosol optical depth (AOD) and Ångström exponent (AE), that are parameters with sufficient long-term records for a first characterization at all sites. At the AERONET sites, microphysical properties derived from inversion of sun-sky radiance data were also examined. AOD (500nm) ranged from 0.08 to 0.10 in Arctic and sub-Arctic sites whereas the aerosol load was higher in more populated areas in Southern Scandinavia (average AOD about 0.10–0.12 at 500 nm).Financial support was provided by: the Spanish CICYT (CGL2008-05939-CO3-01/CLI, CGL2009-09740 and CGL2011-13085-E); the Norwegian Research Council for POLARCAT-Norway; and the Swedish National Space Board and ESA for Norrköping and Palgrunden sites. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement Nr. 262254 [ACTRIS]

Nine years of aerosol optical depth measurements over north-central Spain from ground (AERONET-RIMA) and their comparison with satellite (MODIS) observations

Comunicación presentada en: 2012 European Aerosol Conference (EAC-2012), B-WG01S2P30, celebrada del 2 al 7 de septiembre de 2012 en Granada.Financial supports from the Spanish MICIIN (projects of ref. CGL2008-05939-CO3-01/CLI, CGL 2009-09740, and "Acción Complementaria" CGL2010-09480-E and CGL2011-13085-E), and from the Environmental Council of the CyL Regional Government (Consejería de Medio Ambiente, Junta de Castilla y León) are gratefully acknowledged

Diurnal cycle of precipitable water vapor over Spain

Knowledge of the diurnal cycle of precipitable water vapor (PWV) is very limited owing to the lack of data with sufficient temporal resolution. Currently, GPS receivers have proven to be a suitable technique to determine PWV diurnal variations. In this study, the annual and seasonal diurnal cycles of PWV have been obtained from GPS data for 10 locations over Spain. The minimum value of PWV is reached approximately at the same time at all the stations, ∼0430–0530 UTC, whereas the maximum is reached in the second half of the day, but with a larger dispersion of its occurrence between stations. The annual sub-daily variability ranges from 0.41 to 1.35 mm (3–7%). The highest values are recorded at the stations on the Mediterranean coast, with a doubling of the values of the stations on the Atlantic coast or inland. The winter cycle is quite similar at all locations, whereas in summer local effects are felt strongly, making the diurnal cycle quite different between stations. The PWV mean diurnal cycle is strongest in summer and weakest in spring, with a sub-daily variability of 1.34 and 0.66 mm respectively. Harmonic analysis shows that the first two harmonics can explain 97% of the variance. The diurnal (24 h) harmonic explains 85% of the variance, has mean amplitude of 0.40 mm, and the peak time is from early afternoon to evening. The semi-diurnal (12 h) harmonic is weaker, with an amplitude of 0.13 mm, and peak time between 0400 and 1000 UTC. The diurnal cycle of temperature alone would be a proxy for PWV cycle during the night, but not during the daytime. The breeze regime is the main factor responsible for the phase lag between PWV and temperature cycles during daytime. No clear correlation between the daily cycle of precipitation and PWV has been found

Long-term comparative study of columnar and surface mass concentration aerosol properties in a background environment

Producción CientíficaThe relationship between columnar and surface aerosol properties is not a straightforward problem. The Aerosol Optical Depth (AOD), Ångström exponent (AE), and ground-level Particulate Matter (PMX, x=10 or 2.5 µm) data have been studied from a climatological point of view. Despite the different meanings of AOD and PMx both are key and complementary quantities that quantify aerosol load in the atmosphere and many studies intend to find specific relationships between them. Related parameters such as AE and PM ratio (PR=PM2.5/ PM10), giving information about the predominant particle size, are included in this study on the relationships between columnar and surface aerosol parameters. This study is based on long measurement records (2003–2014) obtained at two nearby background sites from the AERONET and EMEP networks in the north-central area of Spain. The climatological annual cycle of PMx shows two maxima along the year (one in late-winter/early-spring and another in summer), but this cycle is not followed by the AOD which shows only a summer maximum and a nearly bell shape. However, the annual means of both data sets show strong correlation (R=0.89) and similar decreasing trends of 40% (PM10) and 38% (AOD) for the 12-year record. PM10 and AOD daily data are moderately correlated (R=0.58), whereas correlation increases for monthly (R=0.74) and yearly (R=0.89) means. Scatter plots of AE vs. AOD and PR vs. PM10 have been used to characterize aerosols over the region. The PR vs. AE scatterplot of daily data shows no correlation due to the prevalence of intermediate-sized particles. As day-to-day correlation is low (especially for high turbidity events), a binned analysis was also carried out to establish consistent relationships between columnar and surface quantities, which is considered to be an appropriate approach for environmental and climate studies. In this way the link between surface concentrations and columnar remote sensing data is shown to provide useful information for aerosol characterization from a climatological context, despite some limitations.Thanks to MINECO for the financial support of the FPI grant BES-2012-051868; “Juan de la Cierva - Incorporación” grant IJCI-2014-19477 and project CMT2015-66742-R. We also thaks to the Environmental Council of the CyL Regional Government (“Consejería de Medio Ambiente, Junta de Castilla y León”) for supporting this research about atmospheric aerosols as well as Consejería de Educación for supporting the project VA100U14

Study on the influence of different error sources on sky radiance measurements and inversion-derived aerosol products in the frame of AERONET

Comunicación presentada en: 2012 European Aerosol Conference (EAC-2012), B-WG01S2P30, celebrada del 2 al 7 de septiembre de 2012 en Granada.Financial support from the Spanish MICINN under projects with ref. CGL2009-09740, CGL2011-23413, CGL2010-09480-E and CGL2011-13085-E is gratefully acknowledged

Pointing error and field of view of AERONET CIMEL-318 sun photometers

Resumen de la comunicación oral presentada en: 1st Iberian Meeting on Aerosol Science and Technology – RICTA 2013, celebrado del 1 al 3 de julio de 2013 en Évora, Portugal

Columnar and surface aerosol load over the Iberian Peninsula establishing annual cycles, trends, and relationships in five geographical sectors

Producción CientíficaThe study of atmospheric aerosol load over the Iberian Peninsula (IP) under a climatological perspective is accomplished by means of PM10 and AOD440nm measurements from EMEP and AERONET networks, respectively, in the period 2000-2013. The PM10 annual cycles in five Iberian sectors show a main maximum in summer and a secondary in spring, which is only observed in the southern area for the AOD climatology. The characteristics of PM10-AOD annual cycles of each geographical sector are explained by the different climatology of the air mass origins and their apportioning. The two magnitudes are correlated with a factor ranging between 20 and 90 depending on the sector. The temporal evolution of the aerosol load has shown a notable decrease in the IP since the 1980s. Statistically significant trends are obtained in the Northeastern sector with a reduction of 26% (period 1985-2000) for the total suspended particles, which continues for the PM10 data with a value of 35% per decade (2001-2013), and also in the whole column, 61% per decade in the AOD440nm (2004-2013).Financial supports from the Spanish MINECO (projects of ref. CGL2011-23413, CGL2012-33576) are also gratefully acknowledged

Estudio comparativo del vapor de agua en columna en varias estaciones de la Península Ibérica usando diferentes técnicas

Ponencia presentada en: XIV Congreso de la Asociación Española de Teledetección celebrado en Mieres del Camino (Principado de Asturias), del 21 al 23 de septiembre de 2011.Este estudio presenta una caracterización del contenido en columna de vapor de agua o agua precipita- ble (PWV) en 18 localizaciones de la Península Ibérica con 7 años de datos, obtenidos de sondeos, recepto- res GPS, y fotómetros solares. El PWV medio ha sido de 18.06 ± 2.62 mm. En general, el PWV es mayor en las costas, especialmente en la mediterránea, que en el interior. El PWV presenta un claro ciclo anual, con un mínimo en invierno, y un máximo hacia el final del verano. La amplitud media del ciclo es de 13.2 mm, y la razón entre el valor mensual máximo del verano y el mínimo del invierno es aproximadamente 2 en todos los emplazamientos. Las mayores amplitudes del ciclo se registran en la costa mediterránea y los más bajos en el interior. El ciclo anual del PWV sigue al de la temperatura, excepto por el mínimo relativo de PWV que tiene lugar en julio en los emplazamientos del suroeste.Los autores agradecen la financiación al MICIIN de los proyectos de referencias CGL2008-05939-CO3-01/CLI and CGL 2009- 09740 y a la acción complementaria CGL2010- 09480-E. También se agradece al ITACyL para la financiación del proyecto EVACyL

Análisis de 7 años (2002-2008) de datos EOS-MODIS de contenido de vapor de agua sobre la Península Ibérica

Ponencia presentada en: XIV Congreso de la Asociación Española de Teledetección celebrado en Mieres del Camino (Principado de Asturias), del 21 al 23 de septiembre de 2011.Esta investigación complementa un estudio previo sobre el ciclo anual del vapor de agua precipitable (PWV) en la península Ibérica derivado de 7 años de datos de GPS, radiosondeos y fotómetros. En este estudio el ciclo anual de PWV se ha derivado de dos tipos de datos diferentes sensor satelital MODIS obtenidos de la aplicación de dos algoritmos diferentes en las regiones de lejano (IR) y cercano infrarrojo (NIR) respectivamente. Se usa tanto la plataforma Terra como Aqua para el mismo periodo de 7 años (2002-2008) y sobre 15 estaciones EUREF de la península Ibérica. En todos ellos el ciclo anual presenta la forma típica de valores bajos en invierno y valores altos en verano, pero se muestra obviamente el gradiente norte-sur y las variaciones de este a oeste de esta variable atmosférica. También se han evaluado las dife- rencias entre las dos técnicas (IR, NIR) que utiliza MODIS para derivar el PWV. A su vez, los valores anuales se compararon con los obtenidos mediante los datos de red GPS.Agradecemos al equipo de NASA MODIS por los datos de este sensor y al MICIIN por la financiación de los proyectos CGL2008-05939- CO3-01/CLI yCGL2009-09740, y la Acción Complementaria CGL2010-09480-E. También al ITACyL la financiación del Proyecto EVACyL