El monóxido de bromo en la atmósfera: distribución en latitudes subtropicales

Ponencia presentada en: 1er Encuentro sobre Meteorología y Atmósfera de Canarias, celebrado en el Puerto de la Cruz, los días 12,13 y 14 de noviembre de 2003. El encuentro estuvo organizado por el Centro Meteorológico Territorial en Canarias Occidental, con la colaboración del Observatorio Atmosférico de Izaña y del Grupo de Física de la Atmósfera de la Facultad de Física (Universidad de La Laguna)El Área de Investigación e Instrumentación Atmosférica deiiNTA instaló en Noviembre de 2001 en el observatorio Atmosférico de lzaña, bajo el marco del convenio de colaboración INTA-INM, un espectrómetro ultravioleta visible que utilizando la técnica de espectroscopia de absorción diferencial (DOAS) tiene como objetivo la medida rutinaria de monóxido de bromo. En este trabajo se describe muestra la columna slant diferencial de monóxido de bromo, obtenida durante el periodo de medidas comprendido entre Noviembre de 2001 y Noviembre de 2002

Detection of IO in subtropical Free Troposphere

Póster elaborado para la EGU General Assembly celebrada los del 3 al 8 de abril de 2011 en Viena

Long-path averaged mixing ratios of O3 and NO2 in the free troposphere from mountain MAX-DOAS

A new approximation is proposed to estimate O3 and NO2 mixing ratios in the northern subtropical free troposphere (FT). The proposed method uses O4 slant column densities (SCDs) at horizontal and near-zenith geometries to estimate a station-level differential path. The modified geometrical approach (MGA) is a simple method that takes advantage of a very long horizontal path to retrieve mixing ratios in the range of a few pptv. The methodology is presented, and the possible limitations are discussed. Multi-axis differential optical absorption spectroscopy (MAX-DOAS) high-mountain measurements recorded at the Izaña observatory (28° 18' N, 16° 29' W) are used in this study. The results show that under low aerosol loading, O3 and NO2 mixing ratios can be retrieved even at very low concentrations. The obtained mixing ratios are compared with those provided by in situ instrumentation at the observatory. The MGA reproduces the O3 mixing ratio measured by the in situ instrumentation with a difference of 28%. The different air masses scanned by each instrument are identified as a cause of the discrepancy between the O3 observed by MAX-DOAS and the in situ measurements. The NO2 is in the range of 20–40 ppt, which is below the detection limit of the in situ instrumentation, but it is in agreement with measurements from previous studies for similar conditions.We acknowledge the support of AMISOC (Atmospheric Minor Species relevant to the Ozone Chemistry at both sides of the Subtropical jet, contract number CGL2011-24891), and NORS (Demonstration Network of Ground-Based Remote Sensing Observations in support of the GMES Atmospheric Service) integrated project under the 7th Framework Programme (contract number FP7-SPACE-2011-284421)

Improved retrieval of nitrogen dioxide (NO2) column densities by means of MKIV Brewer spectrophotometers

A new algorithm to retrieve nitrogen dioxide (NO2) column densities using MKIV ("Mark IV") Brewer spectrophotometers is described. The method includes several improvements, such as a more recent spectroscopic data set, the reduction of measurement noise, interference by other atmospheric species and instrumental settings, and a better determination of the zenith sky air mass factor. The technique was tested during an ad hoc calibration campaign at the high-altitude site of Izaña (Tenerife, Spain) and the results of the direct sun and zenith sky geometries were compared to those obtained by two reference instruments from the Network for the Detection of Atmospheric Composition Change (NDACC): a Fourier Transform Infrared Radiometer (FTIR) and an advanced visible spectrograph (RASAS-II) based on the differential optical absorption spectrometry (DOAS) technique

Intercomparison of the NO2 vertical column densities measured over Izaña with two ground-based remote sensing techniques: DOAS and FTIR

Ponencia presentada en: XV Congreso de la Asociación Española de Teledetección celebrado en Torrejón de Ardoz (Madrid), del 22 al 24 de octubre de 2013.[ES]En el marco del proyecto NORS se ha realizado una intercomparación de medidas de NO2 con dos técnicas de detección remota desde superficie: DOAS y FTIR. Las columnas verticales de NO2 medidas en Izaña por dos espectrómetros de alta calidad como son el RASAS basado en la técnica DOAS y el instrumento comercial BRUKER-120 basado en la técnica FTIR, han sido comparadas. Debido a la fuerte variación fotoquímica del NO2, las medidas realizadas con el FTIR han sido corregidas con un Box-model fotoquímico para referenciarlas a la hora de medida del RASAS. Los resultados de ambos instrumentos se comparan bien, dando unas diferencias medias de 7±18%.[EN]In the frame of the NORS Project, an intercomparison exercise of two ground-based remote sensing techniques is presented: DOAS and FTIR. Results form two high quality spectrometers located at the Izaña Atmospheric Observatory are shown and compared. DOAS based instruments are two RASAS, developed at INTA, working in the UV-VIS part of the spectrum. FTIR based instrument is a Bruker-120 that measures in the IR. To account for the NO2 strong photochemical variation a Box-model has been used to refer the FTIR data to the DOAS measurement time. Results show a good agreement in the NO2 concentrations. Mean differences are of 7±18%.The work described in this paper is partially supported by the NORS project under the funding of the European Community's Seventh Framework Programme ([FP7/2007-2013]) under grant agreement n°284421 and by the AMISOC project (CGL2011-24891) under the funding of the Spanish Ministry of Economy and Competitiveness (MINECO)

Total ozone measurements from the NDACC Izaña Subtropical Station: visible spectroscopy versus Brewer and satellite instruments

Póster presentado en: Quadrennial Ozone Symposium 2012 celebrado del 27 al 31 de agosto de 2012 en Toronto, CanadáThis work has been partially funded by NORS, UE FP7 Project under grant agreement n° 284421 and AMISOC, CGL2011‐24891, from the Spanish Plan for Research, Development and Innovation

Intercomparison of stratospheric nitrogen dioxide columns retrieved from ground-based DOAS and FTIR and satellite DOAS instruments over the subtropical Izana station

The comparison of observations performed by different techniques and satellite instruments is important. An intercomparison of the stratospheric NO2 derived from ground-based and satellite instruments has been carried out over the Izaña subtropical site. The importance of the use of the effective solar zenith angle when comparing noon measurements with twilight measurements of photochemically active species is highlighted. All instruments show positive trends in NO2 stratospheric column.This publication has been funded by the AVATAR project of the Spanish national funding Agency (MINECO: CGL2014-55230-R ). This work has been carried out in the frame of the NORS (Demonstration Network of Ground-Based Remote Sensing Observations in support of the Copernicus Atmospheric Service) project (funded by the European Community’s Seventh Framework Programme (FP7/2007–2013) under grant agreement no. 284421; http://nors.aeronomie.be/) and has been partially supported by AMISOC project funded by the Spanish national funding Agency (CGL2011-24891)

NO2 VCD Stratospheric trends Hemispheric and latitudinal dependence

Presentación realizada para el 7th International DOAS Workshop celebrado en Bruselas los días 6-8 de julio de 2015Twenty years of stratospheric NO2 VCD data from ground-based zenith DOAS instruments have been used for trend analysis. Spectrometers either NDACC qualified or under evaluation cover Subtropical latitudes in Northern Hemisphere (Izaña, 28ºN), and Southern Antarctic (Marambio, 64ºS) and SubAntarctic (Ushuaia, 55ºS) regions. The multiple linear regression method includes annual, semiannual, quarterly, solar activity cycle, stratospheric aerosols, QBO and NAO proxies. The instruments settings follow the NDACC recommendations for NO2 measurements and the same AMF code. Results show a mean am/pm positive trend of + 7.9% at the 99% confidence level in the Northern Hemisphere station whereas the trends are negative in the Southern Hemisphere ones (-9.8% Ushuaia, -14.9% Marambio). From comparison with FTIR data, it is estimated that the changes are restricted to the lower stratosphere (15-30km) suggesting a dynamic origin of the trend. MIPAS NOy on a global scale shows a similar feature with a redistribution of the nitrogen family within the lower stratosphere

Vertical mass impact and features of Saharan dust intrusions derived from ground-based remote sensing in synergy with airborne in-situ measurements

A study of the vertical mass impact of Saharan dust intrusions is presented in this work. Simultaneous ground-based remote-sensing and airborne in-situ measurements performed during the AMISOC-TNF campaign over the Tenerife area (Canary Islands) in summertime from 01 July to 11 August 2013 were used for that purpose. A particular dusty (DD) case, associated to a progressively arriving dust intrusion lasting for two days on 31 July (weak incidence) and 01 August (strong incidence), is especially investigated. AERONET AOD and AEx values were ranging, respectively, from 0.2 to 1.4 and 0.35 to 0.05 along these two days. Vertical particle size distributions within fine and coarse modes (0.16e2.8 mm range) were obtained from aircraft aerosol spectrometer measurements. Extinction profiles and Lidar Ratio (LR) values were derived from MPLNET/Micro Pulse Lidar observations. MAXDOAS measurements were also used to retrieve the height-resolved aerosol extinction for evaluation purposes in comparison to Lidarderived profiles.This work is supported by the Spanish Ministerio de Economía y Competitividad (MINECO) under grants CGL2011-24891 and CGL2014-55230-R

Iodine monoxide in the north subtropical free troposphere

Iodine monoxide (IO) differential slant column densities (DSCD) have been retrieved from a new multi-axis differential optical absorption spectroscopy (MAX-DOAS) instrument deployed at the Iza˜na subtropical observatory as part of the Network for the Detection of Atmospheric Composition Change (NDACC) programme.We acknowledge the support of the European Commission through the GEOmon (Global Earth Observation and Monitoring) Integrated Project under the 6th Framework Program (contract number FP6-2005-Global-4-036677) and NORS (Demonstration Network Of ground-based Remote Sensing Observations in support of the GMES Atmospheric Service) Integrated Project under the 7th Framework Program (contract number FP7-SPACE- 2011-284421)