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Volcanic plume composition is strongly influenced by both changes in magmatic systems and plume-atmosphere interactions. Understanding the degassing mechanisms controlling the type of volcanic activity implies deciphering the contributions of magmatic gases reaching the surface and their posterior chemical transformations in contact with the atmosphere. Remote sensing techniques based on direct solar absorption spectroscopy provide valuable information about most of the emitted magmatic gases but also on gas species formed and converted within the plumes. In this study, we explore the procedures, performances and benefits of combining two direct solar absorption techniques, high resolution Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet Differential Optical Absorption Spectroscopy (UV-DOAS), to observe the composition changes in the Popocatépetl’s plume with high temporal resolution. The SO2 vertical columns obtained from three instruments (DOAS, high resolution FTIR and Pandora) were found similar (median difference, We acknowledge financial support from grants UNAM-PAPIIT IA101620 and IN111521. NT and TBo also thank the stipend given by the Mexican Foreign Affairs Department (Secretaría de Relaciones Exteriores) and its AMEXCID program. Financial support from Conacyt-AEM through grant No. 275239 is acknowledged.

Accurate accounting of emissions and removals of CO2 is critical for the planning and verification of emission reduction targets in support of the Paris Agreement. Here, we present a pilot dataset of country-specific net carbon exchange (NCE; fossil plus terrestrial ecosystem fluxes) and terrestrial carbon stock changes aimed at informing countries’ carbon budgets. These estimates are based on “top-down” NCE outputs from the v10 Orbiting Carbon Observatory (OCO-2) modeling intercomparison project (MIP), wherein an ensemble of inverse modeling groups conducted standardized experiments assimilating OCO-2 column-averaged dry-air mole fraction (XCO2 ) retrievals (ACOS v10), in situ CO2 measurements or combinations of these data. The v10 OCO-2 MIP NCE estimates are combined with “bottom-up” estimates of fossil fuel emissions and lateral carbon fluxes to estimate changes in terrestrial carbon stocks, which are impacted by anthropogenic and natural drivers. These flux and stock change estimates are reported annually (2015–2020) as both a global 1◦ × 1 ◦ gridded dataset and a country-level dataset and are available for download from the Committee on Earth Observation Satellites’ (CEOS) website: https://doi.org/10.48588/npf6-sw92 (Byrne et al., 2022). Across the v10 OCO-2 MIP experiments, we obtain increases in the ensemble median terrestrial carbon stocks of 3.29–4.58 PgCO2 yr−1 (0.90–1.25 PgC yr−1 ). This is a result of broad increases in terrestrial carbon stocks across the northern extratropics, while the tropics generally have stock losses but with considerable regional variability and differences between v10 OCO-2 MIP experiments. We discuss the state of the science for tracking emissions and removals using top-down methods, including current limitations and future developments towards top-down monitoring and verification systems. This research has been supported by the European Commission, Horizon 2020 Framework Programme (CoCO2 (grant no. 958927 856612/EMME-CARE)) and Copernicus Atmosphere Monitoring Service (grant no. CAMS73), the Australian Research Council (grant nos. DP190100180, DE180100203, DP160100598, LE0668470, DP140101552, DP110103118, DP0879468 and FT180100327), the Environmental Restoration and Conservation Agency (grant no. JPMEERF21S20800), the Korea Meteorological Administration (grant no. KMA2018-00320), the National Aeronautics and Space Administration (grant nos. 20-OCOST20-0004, 80NSSC18K0908, 80NSSC18K0976, 80NSSC20K0006, 80NSSC21K1068, 80NSSC21K1073, 80NSSC21K1077, 80NSSC21K1080, 80HQTR21T0069, NAG512247, NNG05GD07G, NNH17ZDA001N-OCO2 and NNX15AG93G), and the National Oceanic and Atmospheric Administration (grant no. NA18OAR4310266).

On 19 September 2021, a volcanic eruption began on the island of La Palma (Canary Islands, Spain). The eruption has allowed the assessment of an unprecedented multidisciplinary study on the effects of the volcanic plume. This work presents the estimation of the spectral direct radiative forcing (∆F) and efficiency (∆F E f f) from solar radiation measurements at the Izaña Observatory (IZO) located on the island of Tenerife (∼140 km from the volcano). During the eruption, the IZO was affected by different types of aerosols: volcanic, Saharan mineral dust, and a mixture of volcanic and dust aerosols. Three case studies were identified using ground based (lidar) data, satellite-based (Sentinel5P Tropospheric Monitoring Instrument, TROPOMI) data, reanalysis data (Modern-Era Retrospective Analysis for Research and Applications, version 2, MERRA-2), and backward trajectories (Flexible Trajectories, FLEXTRA), and subsequently characterised in terms of optical and micro-physical properties using ground based sun-photometry measurements. Despite the ∆F of the volcanic aerosols being greater than that of the dust events (associated with the larger aerosol load present), the ∆F E f f was found to be lower. The spectral ∆F E f f values at 440 nm ranged between −1.9 and −2.6 Wm−2nm−1AOD−1 for the mineral dust and mixed volcanic and dust particles, and between −1.6 and −3.3 Wm−2nm−1AOD−1 for the volcanic aerosols, considering solar zenith angles between 30◦ and 70◦, respectively. The authors also acknowledge the support of ACTRIS, Ministerio de Ciencia e Innovación of Spain, through the projects SYNERA: PID2020-118793GA-I00 and RT2018- 097864-B-I00, and Junta de Castilla y León grant N◦. VA227P20.

Durante la erupción del volcán de Cumbre Vieja, en la isla de La Palma en 2021, la Agencia Estatal de Meteorología (AEMET), en calidad de Servicio Nacional y Autoridad Meteorológica del Estado, prestó diferentes servicios de apoyo al Comité Científico y al Comité Asesor del Plan de Emergencias Volcánicas de Canarias (PEVOLCA). Parte de sus actividades abarcaron la vigilancia y predicción meteorológica, la monitorización y predicción del transporte del penacho volcánico, y la valoración del impacto de las emisiones de gases y cenizas de la erupción volcánica en la calidad del aire en la isla de La Palma y en la región de Canarias.

Nitrogen dioxide (NO2) air pollution provides valuable information for quantifying NOx emissions and exposures. This study presents a comprehensive method to estimate average tropospheric NO2 emission strengths derived from three-year (April 2018 – March 2021) TROPOMI observations by combining a wind-assigned anomaly approach and a Machine Learning (ML) method, the so-called Gradient Descent. This combined approach is firstly applied to the Saudi Arabian capital city Riyadh, as a test site, and yields a total emission rate of 1.04×1026 molec./s. The ML-trained anomalies fit very well with the wind-assigned anomalies with an R2 value of 1.0 and a slope of 0.99. Hotspots of NO2 emissions are apparent at several sites where the cement plant and power plants are located and over areas along the highways. Using the same approach, an emission rate of 1.80×1025 molec./s is estimated in the Madrid metropolitan area, Spain. Both the estimate and spatial pattern are comparable to the CAMS inventory. We also acknowledge the project of Joint R&D and Talents Program funded by the Qingdao Sino-German Institute of Intelligent Technologies (kh0100020213319) and the project of Transnational Interoperability Rules and Solution Patterns in Collaborative Production Networks based on IDS and GAIA-X funded by Ministry of Science and Technology, PRC (SQ2021YFE010470).

Editors: Emilio Cuevas, Celia Milford and Oksana Tarasova. [EN]The Izaña Atmospheric Research Center (IARC), which is part of the State Meteorological Agency of Spain (AEMET), is a site of excellence in atmospheric science. It manages four observatories in Tenerife including the high altitude Izaña Atmospheric Observatory. The Izaña Atmospheric Observatory was inaugurated in 1916 and since that date has carried out uninterrupted meteorological and climatological observations, contributing towards a unique 100-year record in 2016. This reports are a summary of the many activities at the Izaña Atmospheric Research Center to the broader community. The combination of operational activities, research and development in state-of-the-art measurement techniques, calibration and validation and international cooperation encompass the vision of WMO to provide world leadership in expertise and international cooperation in weather, climate, hydrology and related environmental issues. [ES]El Centro de Investigación Atmosférica de Izaña (CIAI), que forma parte de la Agencia Estatal de Meteorología de España (AEMET), representa un centro de excelencia en ciencias atmosféricas. Gestiona cuatro observatorios en Tenerife, incluido el Observatorio de Izaña de gran altitud, inaugurado en 1916 y que desde entonces ha realizado observaciones meteorológicas y climatológicas ininterrumpidas y se ha convertido en una estación centenaria de la OMM. Estos informes resumen las múltiples actividades llevadas a cabo por el Centro de Investigación Atmosférica de Izaña. El liderazgo del Centro en materia de investigación y desarrollo con respecto a las técnicas de medición, calibración y validación de última generación, así como la cooperación internacional, le han otorgado una reputación sobresaliente en lo que se refiere al tiempo, el clima, la hidrología y otros temas ambientales afines.

We use different methane ground- and space-based remote sensing data sets for investigating the emission strength of three waste disposal sites close to Madrid. We present a method that uses wind-assigned anomalies for deriving emission strengths from satellite data and estimating their uncertainty to 9–14 %. The emission strengths estimated from the remote sensing data sets are significantly larger than the values published in the official register. ESA support through the COCCON-PROCEEDS and COCCON-PROCEEDS II projects. In addition, this research was funded by the Ministerio de Economía y Competitividad from Spain through the INMENSE project (CGL2016-80688-P). This research has largely benefit from funds of the Deutsche Forschungsgemeinschaft (provided for the two projects MOTIV and TEDDY with IDs/290612604 and 416767181, respectively).

We present a global and multi-annual space-borne dataset of tropospheric {H2O, δD} pairs that is based on radiance measurements from the nadir thermal infrared sensor IASI (Infrared Atmospheric Sounding Interferometer) onboard the Metop satellites of EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites). This dataset is an a posteriori processed extension of the MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) IASI full product dataset as presented in Schneider et al. (2021b). From the independently retrieved H2O and δD proxy states, their a priori settings and constraints, and their error covariances provided by the IASI full product dataset we generate an optimal estimation product for pairs of H2O and δD. Here, this standard MUSICA method for deriving {H2O, δD} pairs is extended using an a posteriori reduction of the constraints for improving the retrieval sensitivity at dry conditions. By applying this improved water isotopologue post-processing for all cloud-free MUSICA IASI retrievals, this yields a {H2O, δD} pair dataset for the whole period from October 2014 to June 2019 with a global coverage twice per day (local morning and evening overpass times). In total, the dataset covers more than 1200 million individually processed observations. The retrievals are most sensitivity to variations of {H2O, δD} pairs within the free troposphere, with up to 30 % of all retrievals containing vertical profile information in the {H2O, δD} pair product. After applying appropriate quality filters, the largest number of reliable pair data arises for tropical and subtropical summer regions, but also for higher latitudes there is a considerable amount of reliable data. Exemplary time-series over the Tropical Atlantic and West Africa are chosen to illustrates the potential of the MUSICA IASI {H2O, δD} pair data for atmospheric moisture pathway studiess. Finally, the dataset is referenced with the DOI 10.35097/415 (Diekmann et al., 2021). This work has strongly benefited from the project MUSICA (funded by the European Research Council under the European Communitys Seventh Framework Programme (FP7/2007-2013)/ERC Grant Agreement number 256961), from financial support in the context of the projects MOTIV and TEDDY (funded by the Deutsche Forschungsgemeinschaft under project IDs/Geschäftszeichen 950290612604/GZ:SCHN1126/2-1 and 416767181/GZ:SCHN1126/5-1, respectively) and INMENSE (funded by the Ministerio de Economía y Competividad from Spain, CGL2016-80688-P).

We present a global and multi-annual space-borne dataset of tropospheric {H2O, δD} pairs that is based on radiance measurements from the nadir thermal infrared sensor IASI (Infrared Atmospheric Sounding Interferometer) on board the Metop satellites of EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites). This dataset is an a posteriori processed extension of the MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) IASI full product dataset as presented in Schneider et al. (2021b). From the independently retrieved H2O and δD proxy states, their a priori settings and constraints, and their error covariances provided by the IASI full product dataset, we generate an optimal estimation product for pairs of H2O and δD. Here, this standard MUSICA method for deriving {H2O, δD} pairs is extended using an a posteriori reduction of the constraints for improving the retrieval sensitivity at dry conditions. This research has been supported by the Deutsche Forschungsgemeinschaft (grant no. 290612604, project MOTIV and grant no. 416767181, project TEDDY), the European Research Council, FP7 Ideas: European Research Council (MUSICA, grant no. 256961), the Bundesministerium für Bildung und Forschung (ForHLR supercomputer), the Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg (ForHLR supercomputer), and the Ministerio de Economía y Competitividad (grant no. CGL2016-80688-P, project INMENSE).

The Thermal And Near infrared Sensor for carbon Observation – Fourier Transform Spectrometer (TANSO-FTS) on the Japanese Greenhouse gases Observing SATellite (GOSAT) has been returning data since April 2009. The version 9 (v9) Atmospheric Carbon Observations from Space (ACOS) Level 2 Full Physics (L2FP) retrieval algorithm (Kiel et al., 2019) was used to derive estimates of carbon dioxide (CO2) dry air mole fraction (XCO2) from the TANSO-FTS measurements collected over it's first eleven years of operation. The bias correction and quality filtering of the L2FP XCO2 product were evaluated using estimates derived from the Total Carbon Column Observing Network (TCCON) as well as values simulated from a suite of global atmospheric inverse modeling systems (models). In addition, the v9 ACOS GOSAT XCO2 results were compared with collocated XCO2 estimates derived from NASA's Orbiting Carbon Observatory-2 (OCO-2), using the version 10 (v10) ACOS L2FP algorithm. These tests indicate that the v9 ACOS GOSAT XCO2 product has improved throughput, scatter and bias, when compared to the earlier v7.3 ACOS GOSAT product, which extended through mid 2016. Of the 37 million (M) soundings collected by GOSAT through June 2020, approximately 20 % were selected for processing by the v9 L2FP algorithm after screening for clouds and other artifacts. After post-processing, 5.4 % of the soundings (2M out of 37M) were assigned a “good” XCO2 quality flag, as compared to 3.9 % in v7.3 (

This report provides a technical review of CO2 and CH4 emissions monitoring methods based on surface mixing ratio measurements, total column mixing ratio measurements and flux measurements. The review demonstrated that all these measurements would fulfil respective in situ requirements of the Copernicus CO2 MVS capacity, contributing to the validation of space observations in and around cities and/or the system’s city-scale emissions estimates. The review furthermore elaborated on the benefits to climate change mitigation monitoring in the respective cities and how these methods could be implemented to monitor local emissions. Negotiated procedure No EEA/IDM/R0/17/008. Services supporting the European Environment Agency’s (EEA) crosscutting coordination of the Copernicus In Situ Component

A better understanding of greenhouse gas surface sources and sinks is required in order to address the global challenge of climate change. Spaceborne remote estimations of greenhouse gas atmospheric concentrations can offer the global coverage that is necessary to improve the constraint on their fluxes, thus enabling a better monitoring of anthropogenic emissions. In this work, we introduce the Adaptable 4A Inversion (5AI) inverse scheme that aims to retrieve geophysical parameters from any remote sensing observation. The algorithm is based on Bayesian optimal estimation relying on the Operational version of the Automatized Atmospheric Absorption Atlas (4A/OP) radiative transfer forward model along with the Gestion et Étude des Informations Spectroscopiques Atmosphériques: Management and Study of Atmospheric Spectroscopic Information (GEISA) spectroscopic database. Here, the 5AI scheme is applied to retrieve the column-averaged dry-air mole fraction of carbon dioxide (XCO2) from measurements performed by the Orbiting Carbon Observatory-2 (OCO-2) mission, and uses an empirically corrected absorption continuum in the O2 A-band. For airmasses below 3.0, XCO2 retrievals successfully capture the latitudinal variations of CO2, as well as its seasonal cycle and long-term increasing trend. Comparison with ground-based observations from the Total Carbon Column Observing Network (TCCON) yields a difference of 1.33 ± 1.29 ppm, which is similar to the standard deviation of the Atmospheric CO2 Observations from Space (ACOS) official products. We show that the systematic differences between 5AI and ACOS results can be fully removed by adding an average calculated – observed spectral residual correction to OCO-2 measurements, thus underlying the critical sensitivity of retrieval results to forward modelling. These comparisons show the reliability of 5AI as a Bayesian optimal estimation implementation that is easily adaptable to any instrument designed to retrieve column-averaged dry-air mole fractions of greenhouse gases. This work has received funding from CNES and CNRS.

Ponencia presentada en: XVIII Congreso de la Asociación Española de Teledetección celebrado en Valladolid del 24 al 27 septiembre 2019. [ES]Las áreas urbanas concentran actualmente el 50% de las emisiones globales de Gases de Efecto Invernadero (GEIs). Este porcentaje está aumentando, ya que la población mundial cada vez más se concentra en las áreas urbanas, y se estima que pase del 50% hoy en día al 70% en 2050. Consecuentemente, las medidas de las emisiones urbanas de GEIs, a escalas temporales y espaciales pequeñas, son cruciales para diseñar políticas efectivas de control y mitigación de los GEIs. En este contexto, este trabajo presenta el proyecto MEGEI-MAD (Medida de las Concentraciones de Gases de Efecto Invernadero en Madrid), que es la primera iniciativa española para la monitorización de las emisiones de GEIs en ambientes urbanos. En particular, MEGEI-MAD tiene como objetivo la caracterización completa de las emisiones urbanas de dióxido de carbono (CO2) y metano (CH4), en Madrid, la ciudad más densamente poblada de España. Este objetivo central fue abordado con una campaña de medidas llevada a cabo entre el 16 de Septiembre y el 9 de Octubre de 2018 en la zona metropolitana de Madrid, donde las observaciones de CO2 y CH4 en la columna total atmosférica fueron medidas simultáneamente con observaciones in situ a nivel de superficie. [EN]Urban areas currently contribute over 50% of the global emissions of Greenhouse Gases (GHGs). This percentage is growing since worldwide population is increasingly concentrating in the urban areas, going from over 50% nowadays to 70% by 2050. Consequently, monitoring urban GHGs emissions at small temporal and spatial scales is crucial to design effective GHGs control and mitigation policies. In this context, this work gives an overview of the Project MEGEI-MAD (Monitoring of the Greenhouse Gases Concentrations in Madrid), which is the first Spanish initiative to monitor GHGs emissions in urban environments. Particularly, MEGEI-MAD aims to comprehensively characterize the urban emissions of carbon dioxide (CO2) and methane (CH4) of Madrid, the highest population density city in Spain. This core objective was reached by a field campaign carried out between 16th September-9th October 2018 in the Madrid Metropolitan area, where CO2 and CH4 total column amounts observations have been measured simultaneously with ground-level records.

Ponencia presentada en: XVIII Congreso de la Asociación Española de Teledetección celebrado en Valladolid del 24 al 27 septiembre 2019. [ES]Las áreas urbanas concentran actualmente el 50% de las emisiones globales de Gases de Efecto Invernadero (GEIs). Este porcentaje está aumentando, ya que la población mundial cada vez más se concentra en las áreas urbanas, y se estima que pase del 50% hoy en día al 70% en 2050. Consecuentemente, las medidas de las emisiones urbanas de GEIs, a escalas temporales y espaciales pequeñas, son cruciales para diseñar políticas efectivas de control y mitigación de los GEIs. En este contexto, este trabajo presenta el proyecto MEGEI-MAD (Medida de las Concentraciones de Gases de Efecto Invernadero en Madrid), que es la primera iniciativa española para la monitorización de las emisiones de GEIs en ambientes urbanos. En particular, MEGEI-MAD tiene como objetivo la caracterización completa de las emisiones urbanas de dióxido de carbono (CO2) y metano (CH4), en Madrid, la ciudad más densamente poblada de España. Este objetivo central fue abordado con una campaña de medidas llevada a cabo entre el 16 de Septiembre y el 9 de Octubre de 2018 en la zona metropolitana de Madrid, donde las observaciones de CO2 y CH4 en la columna total atmosférica fueron medidas simultáneamente con observaciones in situ a nivel de superficie. [EN]Urban areas currently contribute over 50% of the global emissions of Greenhouse Gases (GHGs). This percentage is growing since worldwide population is increasingly concentrating in the urban areas, going from over 50% nowadays to 70% by 2050. Consequently, monitoring urban GHGs emissions at small temporal and spatial scales is crucial to design effective GHGs control and mitigation policies. In this context, this work gives an overview of the Project MEGEI-MAD (Monitoring of the Greenhouse Gases Concentrations in Madrid), which is the first Spanish initiative to monitor GHGs emissions in urban environments. Particularly, MEGEI-MAD aims to comprehensively characterize the urban emissions of carbon dioxide (CO2) and methane (CH4) of Madrid, the highest population density city in Spain. This core objective was reached by a field campaign carried out between 16th September-9th October 2018 in the Madrid Metropolitan area, where CO2 and CH4 total column amounts observations have been measured simultaneously with ground-level records.

Ponencia presentada en: XVIII Congreso de la Asociación Española de Teledetección celebrado en Valladolid del 24 al 27 septiembre 2019. [ES]El futuro del sistema Tierra-atmósfera dependerá, en gran medida, de nuestra capacidad para entender todos los procesos que están conduciendo al cambio climático y, en este contexto, los gases de efecto invernadero (GEIs) juegan un papel clave como uno de los principales motores del cambio climático. Con esta idea nace el proyecto INMENSE (IASI for Surveying Methane and Nitrous Oxide in the Troposphere), el cual tiene como objetivo mejorar nuestra compresión de los balances atmosféricos de dos de los más importantes GHGs, el metano (CH4) y el óxido nitroso (N2O). Conocer las distribuciones atmosféricas de CH4 y N2O, tanto a escala local como global así como su variabilidad temporal, es esencial para identificar y cuantificar sus fuentes y sumideros, para predecir su evolución en la atmósfera y su papel en el cambio climático. Para ello, el proyecto INMENSE generará nuevas observaciones de concentraciones de CH4 y N2O en la troposfera media/alta a escala global a partir de las medidas satelitales del sensor IASI (Infrared Atmospheric Sounding Interferometer), que vuela a bordo de los satélites meteorológicos EUMETSAT/Metop. En este trabajo los productos INMENSE CH4 y N2O son presentados, caracterizados y extensamente validados usando una base de datos de referencia multi-plataforma. Esta completa validación nos permite documentar la calidad y consistencia temporal de los nuevos productos IASI de CH4 y N2O, así como su uniformidad geográfica. Por último, mediante la comparativa con simulaciones de modelos químicos de transporte, se analizará el tipo señales de fuentes y sumideros de CH4 y N2O que pueden ser capturadas por las observaciones IASI. [EN]Future of the Earth-atmosphere system will depend, to a large extent, on our capability of understanding all the processes driving climate change and, in this context, of outstanding importance are the monitoring and the investigation of greenhouse gases (GHGs), as main drivers of the Earth’s climate change. With this idea the project INMENSE (IASI for Surveying Methane and Nitrous Oxide in the Troposphere) was born, which aims to improve our current understanding of the atmospheric budgets of two of the most important well-mixed greenhouse gases, methane (CH4) and nitrous oxide (N2O). Knowledge of the atmospheric distributions of CH4 and N2O, from the local to global scales, as well as their variability in time is essential for a better understanding of their sinks and sources, for predicting their evolution in the atmosphere, and their role in climate change. To do so, INMENSE will generate a new global observational data set of middle/upper tropospheric concentrations of CH4 and N2O from the space-based remote sensor IASI (Infrared Atmospheric Sounding Interferometer), on board the meteorological satellites EUMETSAT/Metop. In this work the INMENSE IASI CH4 and N2O products are presented, characterised and comprehensively validated by using a multi-platform reference database. This extensive validation exercise enables us to properly document the quality and long-term consistency of the new IASI CH4 and N2O products as well as their geographical uniformity. Finally, by comparing to chemical transport simulations, the kind of CH4 and N2O sink/source signals that can be captured by IASI observations will be analized.

In a 3.5 year long study, the long term performance of a mobile Bruker EM27/SUN spectrometer, used for greenhouse gases observations, is checked with respect to a co-located reference Bruker IFS 125HR spectrometer, which is part of the Total Carbon Column Observing Network (TCCON). We find that the EM27/SUN is stable on timescales of several years, qualifying it as an useful supplement for the existing TCCON network in remote areas. For achieving consistent performance, such an extension requires careful testing of any spectrometers involved by application of common quality assurance measures. One major aim of the COllaborative Carbon Column Observing Network (COCCON) infrastructure is to provide these services to all EM27/SUN operators. In the framework of COCCON development, the performance of an ensemble of 30 EM27/SUN spectrometers was tested and found to be very uniform, enhanced by the centralized inspection performed at the Karlsruhe Institute of Technology prior to deployment. Taking into account measured instrumental line shape parameters for each spectrometer, the resulting average bias across the ensemble in XCO2 is 0.20 ppm, while it is 0.8 ppb for XCH4. As indicated by the executed long-term study on one device presented here, the remaining empirical calibration factor deduced for each individual instrument can be assumed constant over time. Therefore the application of these empirical factors is expected to further improve the EM27/SUN network conformity beyond the raw residual bias reported above. We acknowledge funding from the Australian Space Research Program - Greenhouse Gas Monitoring Project, the Australian Research Council project DE140100178, and the Centre for Atmospheric Chemistry (CAC) Research Cluster supported by the University of Wollongong Faculty of Science, Medicine and Health.

A 7-year comparison study between measured and simulated LDR under cloud-free conditions has been performed at the BSRN Izaña. Results show an excellent agreement with a mean bias (simulated-measured)

Volume mixing ratio water vapour profiles have been retrieved from IASI (Infrared Atmospheric Sounding Interferometer) spectra using the MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) processor. The retrievals are done for IASI observations that coincide with Vaisala RS92 radiosonde measurements performed in the framework of the GCOS (Global Climate Observing System) Reference Upper-Air Network (GRUAN) in three different climate zones: the tropics (Manus Island, 2°S), mid-latitudes (Lindenberg, 52°N), and polar regions (Sodankylä, 67°N). The retrievals show good sensitivity with respect to the vertical H2O distribution between 1km above ground and the upper troposphere. Typical DOFS (degrees of freedom for signal) values are about 5.6 for the tropics, 5.1 for summertime mid-latitudes, 3.8 for wintertime mid-latitudes, and 4.4 for summertime polar regions. The errors of the MUSICA IASI water vapour profiles have been theoretically estimated considering the contribution of many different uncertainty sources. For all three climate regions, unrecognized cirrus clouds and uncertainties in atmospheric temperature have been identified as the most important error sources and they can reach about 25%. The MUSICA IASI water vapour profiles have been compared to 100 individual coincident GRUAN water vapour profiles. The systematic difference between the data is within 11% below 12km altitude; however, at higher altitudes the MUSICA IASI data show a dry bias with respect to the GRUAN data of up to 21%. The scatter is largest close to the surface (30%), but never exceeds 21% above 1km altitude. The comparison study documents that the MUSICA IASI retrieval processor provides H2O profiles that capture the large variations in H2O volume mixing ratio profiles well from 1km above ground up to altitudes close to the tropopause. Above 5km the observed scatter with respect to GRUAN data is in reasonable agreement with the combined MUSICA IASI and GRUAN random errors. The increased scatter at lower altitudes might be explained by surface emissivity uncertainties at the summertime continental sites of Lindenberg and Sodankylä, and the upper tropospheric dry bias might suggest deficits in correctly modelling the spectroscopic line shapes of water vapour.

Since September 2014, NASA’s Orbiting Carbon Observatory-2 (OCO-2) satellite has been taking measurements of reflected solar spectra and using them to infer atmospheric carbon dioxide levels. This work provides details of the OCO-2 retrieval algorithm, versions 7 and 8, used to derive the column-averaged dry air mole fraction of atmospheric CO2 (XCO2) for the roughly 100,000 cloud-free measurements recorded by OCO-2 each day. The algorithm is based on the Atmospheric Carbon Observations from Space (ACOS) algorithm which has been applied to observations from the Greenhouse Gases Observing SATellite (GOSAT) since 2009, with modifications necessary for OCO-2. Because high accuracy, better than 0.25%, is required in order to accurately infer carbon sources and sinks from XCO2, significant errors and regional-scale biases in the measurements must be minimized. We discuss efforts to filter out poor quality measurements, and correct the remaining good quality measurements to minimize regional-scale biases. Updates to the radiance calibration and retrieval forward model in version 8 have improved many aspects of the retrieved data products. The version 8 data appear to have reduced regionalscale biases overall, and demonstrate a clear improvement over the version 7 data. In particular, error variance with respect to TCCON was reduced by 20% over land and 40% over ocean between versions 7 and 8, and nadir and glint observations over land are now more consistent. While this paper documents the significant improvements in the ACOS algorithm, it will continue to evolve and improve as the CO2 data record continues to expand. Part of this work was conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA) for the Orbiting Carbon Observatory-2 Project. Work at Colorado State University and the Geology and Planetary Sciences Department at the California Institute of Technology was supported by subcontracts from the OCO-2 Project.

Over 20 years of stratospheric NO2 vertical column density (VCD) data from ground-based zenith DOAS spectrometers were used for trend analysis, specifically, via multiple linear regression. Spectrometers from the Network for the Detection of Atmospheric Composition Change (NDACC) cover the subtropical latitudes in the Northern Hemisphere (Izaña, 28° N), the southern Subantarctic (Ushuaia, 55° S) and Antarctica (Marambio, 64° S, and Belgrano, 78° S). The results show that for the period 1993-2014, a mean positive decadal trend of +8.7 % was found in the subtropical Northern Hemisphere stations, and negative decadal trends of-8.7 and-13.8 % were found in the Southern Hemisphere at Ushuaia and Marambio, respectively; all trends are statistically significant at 95 %. Belgrano only shows a significant decadal trend of-11.3 % in the summer/autumn period. Most of the trends result from variations after 2005. The trend in the diurnal build-up per hour (DBU) was used to estimate the change in the rate of N2O5 conversion to NO2 during the day. With minor differences, the results reproduce those obtained for NO2. The trends computed for individual months show large month-to-month variability. At Izaña, the maximum occurs in December (+13.1 %), dropping abruptly to lower values in the first part of the year. In the Southern Hemisphere, the polar vortex dominates the monthly distributions of the trends. At Marambio, the maximum occurs in mid-winter (-21 %), whereas at the same time, the Ushuaia trend is close to its annual minimum (-7 %). The large difference in the trends at these two relatively close stations suggests a vortex shift towards the Atlantic/South American area over the past few years. Finally, the hemispheric asymmetry obtained in this work is discussed in the framework of the results obtained by previous works that considered tracer analysis and Brewer-Dobson circulation. The results obtained here provide evidence that the NO2 produced by N2O decomposition is not the only cause of the observed trend in the stratosphere and support recent publications pointing to a dynamical redistribution starting in the past decade. Fil: Yela, Margarita. Instituto Nacional de Tecnica Aeroespacial; España Fil: Gil-Ojeda, Manuel. Instituto Nacional de Tecnica Aeroespacial; España Fil: Navarro-Comas, Mónica. Instituto Nacional de Tecnica Aeroespacial; España Fil: Gonzalez-Bartolomé, David. Instituto Nacional de Tecnica Aeroespacial; España Fil: Puentedura, Olga. Instituto Nacional de Tecnica Aeroespacial; España Fil: Funke, Bernd. Instituto de Astrofísica de Andalucía; España Fil: Iglesias, Javier. Instituto Nacional de Tecnica Aeroespacial; España Fil: Rodríguez, Santiago. Instituto Nacional de Tecnica Aeroespacial; España Fil: García, Omaira. Centro de Investigación Atmosférica de Izaña; España Fil: Ochoa, Héctor. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Deferrari, Guillermo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego; Argentina

The project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) has shown that the sensor IASI aboard the satellite MetOp can measure the free tropospheric {H2O,δD} pair distribution twice per day on a quasi-global scale. Such data are very promising for investigating tropospheric moisture pathways, however, the complex data characteristics compromise their usage in the context of model evaluation studies. Here we present a tool that allows for simulating MUSICA MetOp/IASI {H2O,δD} pair remote sensing data for a given model atmosphere, thereby creating model data that have the remote sensing data characteristics assimilated. This model data can then be compared to the MUSICA data. The retrieval simulation method is based on the physical principles of radiative transfer and we show that the uncertainty of the simulations is within the uncertainty of the MUSICA MetOp/IASI products, i.e. the retrieval simulations are reliable enough. We demonstrate the working principle of the simulator by applying it to ECHAM5-wiso model data. The few case studies clearly reveal the large potential of the MUSICA MetOp/IASI {H2O,δD} data pairs for evaluating modelled moisture pathways. The tool is made freely available in form of MATLAB and Python routines and can be easily connected to any atmospheric water vapour isotopologue model.

An increase of 0.31 ± 0.03 % year−1 of atmospheric methane is reported using 10 years of solar observations performed at 10 ground-based stations since 2005. These trend agree with a GEOS-Chem-tagged simulation that accounts for the contribution of each emission source and one sink in the total methane. The GEOS-Chem simulation shows that anthropogenic emissions from coal mining and gas and oil transport and exploration have played a major role in the increase methane since 2005. W. Bader has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 704951, and from the University of Toronto through a Faculty of Arts & Science Postdoctoral Fellowship Award. E. Mahieu is a Research Associate with the F.R.S.–FNRS. The F.R.S.–FNRS further supported this work under Grant no. J.0093.15 and the Fédération Wallonie Bruxelles contributed to supporting observational activities. The Centre for Atmospheric Chemistry at the University of Wollongong involvement in this work is funded by Australian Research Council projects DP1601021598 and LE0668470.

Tropospheric water vapour isotopologue distributions have been consistently generated and quality-filtered for 12 globally distributed ground-based FTIR sites. The products are provided as two data types. The first type is best-suited for tropospheric water vapour distribution studies. The second type is needed for analysing moisture pathways by means of {H2O,δD}-pair distributions. This paper describes the data types and gives recommendations for their correct usage. We gratefully acknowledge the support by the SFB/TR 172 “ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC) 3” in Projects B06 and E02 funded by the DFG. Eliezer Sepúlveda is supported by the Ministerio de Economía y Competitividad from Spain under the project CGL2012-37505 (NOVIA project). The measurements in Mexico (Altzomoni) are supported by UNAM-DGAPA grants (IN109914, IN112216) and Conacyt (239618, 249374). Start-up of the measurements in Altzomoni was supported by the International Bureau of BMBF under contract no. 01DN12064. This study has been conducted in the framework of the project MUSICA, which was funded by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement number 256961.

This work presents an observational data set of upper tropospheric CH4 and N2O products retrieved from the thermal emission spectra measured by the satellite sensor IASI (Infrared Atmospheric Sounding Interferometer), aboard the EUMETSAT satellites MetOp. The quality of the products is documented by an theoretical error estimation and by an extensive comparison study to HIPPO aircraft in-situ data. The research leading to these results has received funding from the European Research Council under FP7/(2007-2013)/ERC Grant agreement n◦256961 (project MUSICA), from the Ministerio de Economía y Competitividad from Spain trough the project CGL2012-37505 (project NOVIA), from the Ministerio de Educación, Cultura y Deporte (Programa "José Castillejo", CAS14/00282), and from EUMETSAT under its Fellowship Programme (project VALIASI).

NASA’s Orbiting Carbon Observatory-2 (OCO-2) has been measuring carbon dioxide column-averaged dryair mole fraction, XCO2 , in the Earth’s atmosphere for over 2 years. In this paper, we describe the comparisons between the first major release of the OCO-2 retrieval algorithm (B7r) and XCO2 from OCO-2’s primary ground-based validation network: the Total Carbon Column Observing Network (TCCON). The OCO-2 XCO2 retrievals, after filtering and bias correction, agree well when aggregated around and coincident with TCCON data in nadir, glint, and target observation modes, with absolute median differences less than 0.4 ppm and RMS differences less than 1.5 ppm. After bias correction, residual biases remain. These biases appear to depend on latitude, surface properties, and scattering by aerosols. It is thus crucial to continue measurement comparisons with TCCON to monitor and evaluate the OCO-2 XCO2 data quality throughout its mission.

Presentación de la clase impartida en el Observatorio Atmosférico de Izaña, el 18 de junio de 2016, con motivo del curso "Conceptos Básicos de Composición Atmosférica"

This paper describes the comparisons between NASA's Orbiting Carbon Observatory (OCO-2) column-averaged dry-air mole fractions of CO2 with its primary ground-based validation network, the Total Carbon Column Observing Network (TCCON). The paper shows that while the standard bias correction does a good job of reducing spurious variability globally in the satellite measurements, local biases remain.

We present two years of measurements of water vapour (H2O) and its isotopologue ratio (δD, the standardized ratio between H216O and HD16O) made at two remote mountain sites on Tenerife Island in the subtropical North Atlantic. We show that the data – if measured during nighttime – are well representative for the lower/middle free troposphere. We use the measured H2O-δD pairs, together with dust measurements and back-trajectory modelling for analysing the moisture pathways to this region. We can identify four principally different transport pathways. The first two pathways are linked to transport from high altitudes and high latitudes, whereby the respective air can be dry, due to last condensation occurring at low temperatures, as well as humid, due to cross isentropic mixing with lower level and more humid air during transport since last condensation. The third pathway is transport from lower latitudes and lower altitudes, whereby we can identify rain re-evaporation as an occasional source of moisture. The fourth pathway is linked to the African continent, where during summer dry convection processes over the Sahara very effectively inject humidity from the boundary layer to higher altitudes. This so-called Saharan Air Layer (SAL) is then advected westward over the Atlantic and contributes to moisten the free troposphere. We demonstrate that different pathways leave distinct fingerprints on the measured H2O-δD pairs. This study has been conducted in the framework of the project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water), funded by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013/ ERC Grant agreement number 256961). Aerosol measurements are part of the project POLLINDUST (CGL2011-26259), funded by the Minister of Economy and Competitiveness of Spain. The AERONET sun photometer at Izana (PI: Emilio Cuevas) has been calibrated within AERONET EUROPE TNA supported by the European Community Research Infrastructure Action under the FP7 Capacities programme for Integrating Activities, ACTRIS grant agreement number 262254. Eliezer Sepúlveda is supported by the NOVIA project (Ministerio de Economía y Competitividad of Spain, CGL2012-37505).

In this study, we revise the index that quantifies the North African Dipole Intensity (NAFDI), and explain its relationship with the Saharan Heat Low (SHL) and mid-latitude Rossby waves. We find outstanding similarities of meteorological patterns associated with the positive NAFDI and the SHL West-phase on the one hand, and with the negative NAFDI and the SHL East-Phase, on the other hand. We introduce the daily NAFDI index and the daily SHL West-East Displacement Index (SHLWEDI). The Pearson correlation coefficient between the daily SHLWEDI 1-day lagged and the daily NAFDI for the period 1980–2013 20 June–17 September is fairly high (r = 0.77). The correlation reduces to 0.69 if the SHLWEDI is not lagged. We observe that the SHL West-phase is significantly more frequent than the SHL East-phase, and that the SHL is more intense during its East-phase. Part of this study was performed in the frame of AEROATLAN (grant 2015-66229), funded by the Ministry of Economy and Competitiveness of Spain.

Comunicación presentada en: TECO-2016 (Technical Conference on Meteorological and Environmental Instruments and Methods of Observation) celebrada en Madrid, del 27 al 30 de septiembre de 2016.

An increase of 0.31 ± 0.03 % year−1 of atmospheric methane is reported using 10 years of solar observations performed at 10 ground-based stations since 2005. These trend agree with a GEOS-Chem-tagged simulation that accounts for the contribution of each emission source and one sink in the total methane. The GEOS-Chem simulation shows that anthropogenic emissions from coal mining and gas and oil transport and exploration have played a major role in the increase methane since 2005. E. Mahieu is Research Associate with the F.R.S. – FNRS. The F.R.S. 20 – FNRS further supported this work under Grant nº J.0093.15 and the Fédération Wallonie Bruxelles contributed to observational activities support.The Centre for Atmospheric Chemistry at the University of Wollongong involvement in this work is funded by Australian Research Council projects DP1601021598 and LE0668470.

In the lower/middle troposphere H2O-δD pairs are good proxies for moisture pathways, however their observation is challenging. The project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) addresses this challenge by integrating remote sensing with in-situ measurement techniques. The aim is to retrieve accurate tropospheric H2O-δD pairs from the middle infrared spectra measured from ground by the FTIR (Fourier Transform InfraRed) spectrometers of the NDACC (Network for the Detection of Atmospheric Composition Change) and the thermal nadir spectra measured by IASI (Infrared Atmospheric Sounding Interferometer) aboard the MetOp satellites. In this paper we review the MUSICA framework, present the final MUSICA products, and outline the NDACC/FTIR’s and METOP/IASI’s potential for observing accurate and consistent H2O-δD data pairs. First, we briefly resume the particularities of an H2O-δD pair retrieval. Second, we show that the remote sensing data of the final product version are absolutely calibrated with respect to H2O and δD in-situ profile references measured in the subtropics, between 0 and 7 km. Third, we empirically demonstrate that the calibrated remote sensing H2O-δD pairs can identify different lower/middle tropospheric moisture pathways and advert to the risk of misinterpretations caused by an incorrect processing of such remote sensing data. Fourth, we reveal that the different sensors (NDACC/FTIR instruments, MetOp/IASI-A, and MetOp/IASI-B) provide consistent H2O-δD pairs for very distinct atmospheric clear sky conditions. Fifth, we document the unique possibilities of the NDACC/FTIR instruments for providing long-term records (important for climatological studies) and of the MetOp/IASI sensors for observing diurnal signals on quasi global scale and with high horizontal resolution. This study has been conducted in the framework of the project MUSICA which is funded by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013) / ERC Grant agreement number 256961. E. Sepúlveda is supported by the Ministerio de Economía and Competitividad of Spain for the project NOVIA (CGL2012-37505). The aircraft campaign has been co-funded by the project MUSICA and the Spanish national project AMISOC (CGL2011-24891). The AERONET sun photometer at Izaña (PI: Dr. Emilio Cuevas) has been calibrated within AERONET EUROPE TNA supported by the European Community Research Infrastructure Action under the FP7 Capacities program for Integrating Activities, ACTRIS grant agreement number 262254. The Izaña aerosol in-situ measurements are part of the project POLLINDUST (CGL2011-26259) funded by the Minister of Economy and Competitiveness of Spain.

Tropospheric {H2O,δD} pairs can be observed by remote sensing techniques, but the data quality strongly depends on a comprehensive consideration of the complex nature and a careful calibration of the remote sensing data pairs. This paper reviews the quality assurance/documentation activities of the MUSICA project and demonstrates that MUSICA’s ground-based FTIR and space-based IASI {H2O,δD} pair products are accurate and can be generated at a global scale with high resolution and for long periods. This study has been conducted in the framework of the project MUSICA which is funded by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013) / ERC Grant agreement number 256961. E. Sepúlveda is supported by the Ministerio de Economía and Competitividad of Spain for the project NOVIA (CGL2012-37505). The aircraft campaign has been co-funded by the project MUSICA and the Spanish national project AMISOC (CGL2011-24891). The AERONET sun photometer at Izaña (PI: Dr. Emilio Cuevas) has been calibrated within AERONET EUROPE TNA supported by the European Community Research Infrastructure Action under the FP7 Capacities program for Integrating Activities, ACTRIS grant agreement number 262254. The Izaña aerosol in-situ measurements are part of the project POLLINDUST (CGL2011-26259) funded by the Minister of Economy and Competitiveness of Spain.

A 1-year intercomparison of classical and modern radiation and sunshine duration instruments has been performed at Izaña Atmospheric Observatory. We compare global solar radiation (GSR) records measured with a Kipp & Zonen CM-21 pyranometer, taken in the framework of the Baseline Surface Radiation Network, with those measured with a multifilter rotating shadowband radiometer and a bimetallic pyranometer, and with GSR estimated from sunshine duration performed with a CS sunshine recorder.

Tropospheric water vapour isotopologue distributions have been consistently generated and quality filtered for 12 globally distributed ground-based FTIR sites. The products are provided as two data types. The first type is best-suited for tropospheric water vapour distribution studies. The second type is needed for analysing moisture pathways by means of {H2O,δD}-pair distributions. This paper describes the data types and gives recommendations for their correct usage. E. Sepúlveda is supported by the Ministerio de Economía y Competitividad from Spain under the project CGL2012-37505 (NOVIA project). The measurements in Mexico (Altzomoni) are supported by UNAM-DGAPA grants (IN109914, IN112216) and Conacyt (239618, 249374). Start-up of the measurements in Altzomoni was supported by International Bureau of BMBF under contract no. 01DN12064. 15 Special thanks to A. Bezanilla for data management and the RUOA program (www.ruoa.unam.mx) and personnel for helping maintaining the station. Measurements at Wollongong are supported by the Australian Research Council, grant DP110103118. This study has been conducted in the framework of the project MUSICA which is funded by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013) / ERC Grant agreement number 256961.

Tropospheric {H2O,δD} pairs can be observed by remote sensing techniques, but the data quality strongly depends on a comprehensive consideration of the complex nature and a careful calibration of the remote sensing data pairs. This paper reviews the quality assurance/documentation activities of the MUSICA project and demonstrates that MUSICA’s ground-based FTIR and space-based IASI {H2O,δD} pair products are accurate and can be generated at a global scale with high resolution and for long periods. This study has been conducted in the framework of the project MUSICA which is funded by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement number 256961. E. Sepúlveda is supported by the Ministerio de Economía and Competitividad of Spain for the project NOVIA (CGL2012-37505). The aircraft campaign has been co-funded by the project MUSICA and the Spanish national project AMISOC (CGL2011- 24891). The AERONET sun photometer at Izaña (principal investigator: Emilio Cuevas) has been calibrated within AERONET EUROPE TNA supported by the European Community Research Infrastructure Action under the FP7 Capacities program for Integrating Activities, ACTRIS grant agreement number 262254. The Izaña aerosol in situ measurements are part of the project POLLINDUST (CGL2011-26259) funded by the Minister of Economy and Competitiveness of Spain.

Título del artículo final: 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).

The characteristics of {H2O,δD} pair space-based remote sensing data depend on the atmospheric and surface conditions, which compromises their usage for model evaluation studies. This paper shows how the problem can be overcome by simulating MUSICA MetOp/IASI {H2O,δD} remote sensing products for any given model atmosphere. The remote sensing retrieval simulator is freely provided as a MATLAB and Python routine. This study has been conducted in the framework of the project MUSICA which is funded by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013) / ERC Grant agreement number 256961.

Within the NDACC (Network for the Detection of Atmospheric Composition Change), more than 20 FTIR (Fourier-transform infrared) spectrometers, spread worldwide, provide long-term data records of many atmospheric trace gases. We present a method that uses measured and modelled XCO2 for assessing the consistency of these NDACC data records. Our XCO2 retrieval setup is kept simple so that it can easily be adopted for any NDACC/FTIR-like measurement made since the late 1950s. By a comparison to coincident TCCON (Total Carbon Column Observing Network) measurements, we empirically demonstrate the useful quality of this suggested NDACC XCO2 product (empirically obtained scatter between TCCON and NDACC is about 4‰ for daily mean as well as monthly mean comparisons, and the bias is 25‰). Our XCO2 model is a simple regression model fitted to CarbonTracker results and the Mauna Loa CO2 in situ records. A comparison to TCCON data suggests an uncertainty of the model for monthly mean data of below 3‰. We apply the method to the NDACC/FTIR spectra that are used within the project MUSICA (multi-platform remote sensing of isotopologues for investigating the cycle of atmospheric water) and demonstrate that there is a good consistency for these globally representative set of spectra measured since 1996: the scatter between the modelled and measured XCO2 on a yearly time scale is only 3‰. This study has been conducted in the framework of the project MUSICA, which is funded by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007–2013)/ERC Grant agreement number 256961.

This paper presents the reconstruction of a 73-year time series of the aerosol optical depth (AOD) at 500 nm at the subtropical high-mountain Izaña Atmospheric Observatory (IZO) located in Tenerife (Canary Islands, Spain). For this purpose, we have combined AOD estimates from artificial neural networks (ANNs) from 1941 to 2001 and AOD measurements directly obtained with a Precision Filter Radiometer (PFR) between 2003 and 2013. The analysis is limited to summer months (July–August–September), when the largest aerosol load is observed at IZO (Saharan mineral dust particles). The ANN AOD time series has been comprehensively validated against coincident AOD measurements performed with a solar spectrometer Mark-I (1984–2009) and AERONET (AErosol RObotic NETwork) CIMEL photometers (2004–2009) at IZO, obtaining a rather good agreement on a daily basis: Pearson coefficient, R, of 0.97 between AERONET and ANN AOD, and 0.93 between Mark-I and ANN AOD estimates. In addition, we have analysed the long-term consistency between ANN AOD time series and long-term meteorological records identifying Saharan mineral dust events at IZO (synoptical observations and local wind records). Both analyses provide consistent results, with correlations > 85 %. Therefore, we can conclude that the reconstructed AOD time series captures well the AOD variations and dust-laden Saharan air mass outbreaks on short-term and long-term timescales and, thus, it is suitable to be used in climate analysis. The AERONET Cimel sun photometer at Izaña has been calibrated by AERONET-EUROPE Calibration Service, financed by the Aerosol Cloud and TRace gas InfraStructure (ACTRIS) European Research Infrastructure Action (FP7/2007-2013 no. 262254). Financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) and from the “Fondo Europeo de Desarrollo Regional” (FEDER) for project CGL2012-33576 is gratefully acknowledged.

We present two years of measurements of water vapour (H2O) and its isotopologue ratio (δD, the standardized ratio between H216O and HD16O) made at two remote mountain sites on Tenerife Island in the subtropical North Atlantic. We show that the data – if measured during nighttime – are well representative for the lower/middle free troposphere. We use the measured H2O-δD pairs, together with dust measurements and back-trajectory modelling for analysing the moisture pathways to this region. This study has been conducted in the framework of the project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water), funded by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013/ ERC Grant agreement number 256961). Aerosol measurements are part of the project POLLINDUST (CGL2011-26259), funded by the Minister of Economy and Competitiveness of Spain. The AERONET sun photometer at Izana (PI: Emilio Cuevas) has been calibrated within AERONET EUROPE TNA supported by the European Community Research Infrastructure Action under the FP7 Capacities programme for Integrating Activities, ACTRIS grant agreement number 262254. Eliezer Sepúlveda is supported by the NOVIA project (Ministerio de Economía y Competitividad of Spain, CGL2012-37505).

Póster elaborado para el International Symposium CLIMA-ES 2015 celebrado en Tortosa, Spain, los días 11-13 March 2015. Solar radiation controls the energy radiative balance in the Earth and, thus, our weather and climate. For this reason, its study has been one of the main objectives of the research community during the last decades. Recently, the focus is on evaluating long-term trends of solar radiation reaching the Earth‟s surface as well as on identifying the variability driven by the climate change. Observational evidences of changes on global solar radiation (GSR) trends have already been reported at a global scale. In this context, the goal of this work is to perform a reconstruction of the GSR time series between 1933 and 2013 at the subtropical high-mountain Izaña Atmospheric Observatory (IZA) located in Tenerife (28.3°N, 16.5°W, 2373 m a.s.l., Spain). For this purpose, we combine GSR estimates from sunshine duration (SD) data using the Ångström–Prescott method over the 1933/1991 period, and GSR observations directly performed by different pyranometers between 1992 and 2013. This work was developed under the Specific Agreement of Collaboration between the Meteorological State Agency (AEMET) of Spain and the University of Valladolid. Financial supports from the Spanish Ministry of Economy and Competitiveness (MINECO) and from the “Fondo Europeo de Desarrollo Regional” (FEDER) for projects CGL2011-23413, CGL2012-33576 and CGL2012-37505 are gratefully acknowledged.

Seminario realizado para el SPARC regional workshop on the "Role of the stratosphere in climate variability and prediction", celebrado los días 12-13 de enero de 2015 en Granada En esta presentación se proporciona un resumen de las actividades FTS en el CIAI, focalizada en la monitorización a largo plazo de la composición gaseosa atmosférica (especies relacionadas con el ozono y gases de efecto invernadero) y la validación de medidas remotas desde satélite y modelos climáticos. En particular, se muestra el gran potencial de las observaciones FTS para monitorizar e investigar la troposfera, la estratosfera y sus procesos de intercambio.

Póster elaborado para el International Symposium CLIMA-ES 2015, Tortosa, Spain, 11-13 March 2015. A 73-year time series of the daily aerosol optical depth (AOD) at 500 nm has been reconstructed from 1941 to 2013 at the subtropical high-mountain Izaña Global Atmospheric Watch (GAW) Observatory (IZO) located in Tenerife Island (The Canary Islands, Spain ; 28º 18’ N, 16º 29’W, 2.367 ma.s.l) For this purpose, we have combined AOD estimates from Artificial Neuronal Networks (ANNs) from 1941 to 2001, and AOD measurements directly performed with Precision Filter Radiometer (PFR) between 2003 and 2013. Theanalysis is limited to cloud-free conditions (Oktas=0) and to the summer season (JAS), where the largest aerosol load is observed at IZO (Saharan mineral dust particles). In order to account for the observed AOD inter-annual/decadal variations, we have done a preliminary study about the relationship between AOD time series and the large-scale climatic indexes, such as the Atlantic Multidecadal Oscillation (AMO), obtaining a significant anti-correlation. This work was developed under the Specific Agreement of Collaboration between the Meteorological State Agency (AEMET)of Spain and the University of Valladolid. Financial supports from the Spanish Ministry of Economy and Competitiveness (MINECO)and from the “Fondo Europeo de Desarrollo Regional” (FEDER)forprojectsCGL2011-23413,CGL2012-33576andCGL2012-37505 are gratefully acknowledged.

Atmospheric remote sounding from space is fundamental for investigating the processes driving climate change. However, for a correct scientific interpretation of these records a documentation of their quality is required. In this context, this paper exploits the high potential of the Izaña Atmospheric Observatory, as a ground-based reference site, to perform the first comprehensive validation of the EUMETSAT atmospheric trace gas products O3, CH4, N2O, CO and CO2 of the remote sensor IASI. The research leading to these results has received funding from the Ministerio de Economía y Competitividad from Spain for the project CGL2012-37505 (NOVIA project) and from EUMETSAT under the Fellowship Programme (VALIASI project). Furthermore, M. Schneider, S. Barthlott, A. Wiegele, and Y. González are supported by the European Research Council under FP7/(2007–2013)/ERC grant agreement no. 256961 (MUSICA project).

his study examines the possibility of ground-based remote-sensing ozone total column amounts (OTC) from spectral signatures at 3040 and 4030 cm−1. These spectral regions are routinely measured by the NDACC (Network for the Detection of Atmospheric Composition Change) ground-based FTIR (Fourier transform infraRed) experiments. In addition, they are potentially detectable by the TCCON (Total Carbon Column Observing Network) FTIR instruments. The ozone retrieval strategy presented here estimates the OTC from NDACC FTIR high-resolution spectra with a theoretical precision of about 2 and 5% in the 3040 and 4030 cm−1 regions, respectively. Empirically, these OTC products are validated by inter-comparison to FTIR OTC reference retrievals in the 1000 cm−1 spectral region (standard reference for NDACC ozone products), using an 8-year FTIR time series (2005–2012) taken at the subtropical ozone supersite of the Izaña Atmospheric Observatory (Tenerife, Spain). Associated with the weaker ozone signatures at the higher wave number regions, the 3040 and 4030 cm−1 retrievals show lower vertical sensitivity than the 1000 cm−1 retrievals. The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 284421 (NORS project) and from the Ministerio de Economía and Competitividad from Spain for the project CGL2012-37505 (NOVIA project). M. Schneider and Y. González are supported by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC Grant agreement no. 256961 and E. Sepúlveda is supported by the NOVIA Project.

We present lower/middle tropospheric column-averaged CH4 mole fraction time series measured by nine globally distributed ground-based FTIR (Fourier transform infrared) remote sensing experiments of the Network for the Detection of Atmospheric Composition Change (NDACC). We show that these data are well representative of the tropospheric regional-scale CH4 signal, largely independent of the local surface small-scale signals, and only weakly dependent on upper tropospheric/lower stratospheric (UTLS) CH4 variations. At Ny-Ålesund and Izaña, the FTIR work has received funding from the European Community’s Seventh Framework Programme ([FP7/2007–2013]) under grant agreement no. 284421 (see Article II.30. of the Grant Agreement). At Izaña has also received funding from the Ministerio de Economía and Competitividad from Spain for the project CGL2012-37505 (NOVIA project). This study has strongly benefited from work made in the framework of the project MUSICA, which is funded by the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007–2013)/ERC grant agreement number 256961.