Atmospheric Chemistry and Climate Group
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The AC2 group is involved in numerous field studies designed to improve our understanding of the atmosphere. Most of our field activities are focused on the measurement of halogen species, ozone, nitrogen oxides, formaldehyde and glyoxal. This page describes briefly, some of the projects that AC2 is involved in:


Pyrenees Campaign
Pic du Midi de Bigorre Observatory

Campagin during Septemeber 2013 at the Pic du Midi Observatory in the French Pyrenees in collaboration with the Laboratoire Geosciences Environnement Toulouse (GET).

The objectives of these campaing are the detection of halogen compounds (IO, BrO y I2), volatile organic compounds (HCHO y CHOCHO), NOx (NO2 y NO3) y ozone to define their concentration in the free troposphere, study their vertical distribution, investigate their sources, sinks and pathways, and asses their impact on the oxidising capacity of the atmosphere.

To perform this campaign the MAX-DOAS and LP-DOAS instruments will be deployed at the Pic du Midi Observatory at 2877m height.

 MG 4397 small

AMISOC (Atmospheric Minor Species relevant to the Ozone Chemistry at both sides of the jet) is a campaign organised by the National Institute for Aerospace Technology (INTA)

AC2 is taking part in this campaign measuring BrO, IO, NO2, HCHO and CHOCHO at mount Teide by means of the LP-DOAS and MAX-DOAS instruments during July 2013. AC2 is also involved in the modelling of the trace gases and particles results to interpret the data.


Climate and HAlogen Reactivity tropicaL EXperiment (CHARLEX)

The interest in the impact of reactive halogen species in the troposphere has increased in the last two decades following observations of iodine and bromine oxide radicals (IO and BrO) at various locations around the world [e.g. Alicke et al., 1999; Saiz-Lopez et al., 2004; Whalley et al., 2007: Read et la., 2008]. Halogens alter the oxidizing capacity of the atmosphere in several important ways: by destroying ozone (O3), by changing hydrogen oxide (OH, HO2) and nitrogen oxide (NO, NO2) radical chemistry and, in the case of chlorine and bromine radicals, by oxidising species such as dimethyl sulphide (DMS) directly. Furthermore, the higher iodine oxide species condense spontaneously to form ultrafine particles and are implicated in the formation of cloud condensation nuclei [O'Dowd et al., 2002; Saunders and Plane, 2005]. However, the exact role of halogens in the remote marine boundary layer is still not clear with few observations in the past [Allan et al., 200; Read et al., 2008]. In particular there are no direct reported observations in the tropical Pacific marine boundary layer with only satellite measurements indicating large levels of IO [Schönhardt et al., 2007]. Interestingly, In the equatorial southern hemisphere Pacific, O3 often drops to concentrations of less than 5 ppb [e.g. Johnson et al., 1990], particularly in late summer, which cannot be explained by surface deposition and photolysis losses.

CHARLEX is designed with an aim to, (a) validate the satellite observations of high IO in the region, (b) characterise the role of halogen species in the Pacific remote marine boundary layer, (c) to explain the very low surface O3 values observed in the past and (d) determine whether the levels of IO observed here can lead to particle formation and subsequent CCN formation.

AC2 will be leading a year-long campaign based at Isabella, on the Galapagos Island achipelago, with continuous measurements of IO, BrO, OIO, I2, NOx, O3 and meteorological data available through the measurement period. These measurements will be made in collaboration with the Unviersity of Leeds.


Malaspina 2010-11
Malaspina 2010

Lead by the Spanish Ministry of Science and Innovation (MICINN) and the Spanish Research Council (CSIC), the Malaspina expedition on board of the R/V Hesperides circumnavigated the World in 2010-2011 with the objective of studying the physical oceanography, biogeochemistry and microbiological biodiversity of the oceans, and the exchange of gases and pollutants between the ocean surface and the atmosphere ( The main objective of Malaspina was evaluating the impacts of global change on the oceans from a multidisciplinary point of view.

AC2 has participated in Malaspina with a MAX-DOAS system and a surface ozone monitor, in order to collect a large and highly-resolved database of atmospheric trace gases and radicals. This database will allow us to describe the spatial and temporal distribution of atmospherically relevant trace molecules such as IO, BrO, HCHO and (CHO)2, improving our knowledge on atmosphere-ocean interactions and their relationship with the chemical composition of the atmosphere and the climate.


HaloCarbon Air Sea Transect-Pacific (HaloCAST-P)

The HaloCarbon Air Sea Transect - Pacific (HaloCAST-P) cruise is part of an effort to study the spatial/temporal variability of methyl bromide (CH3Br) and other halocarbons in the upper ocean in response to the implementation of the Montreal Protocol and its amendments [UNEP, 1995]. This study is strongly related to Surface Ocean Lower Atmosphere Studies (SOLAS) goals. The long-term goals of this work are to understand the origin and cycling of CH3Br and other halocarbons in the oceans, and to develop a predictive capability for how the air/sea fluxes of oceanic trace gases will respond to the coming global changes in atmosphere/ocean chemistry and climate. This project is supported by the National Science Foundation (ARRA 0927874).

AC2 will be installing a MAX-DOAS instrument on board the R/V Thomas Thompson cruise as a complimentary study to HaloCAST-P. The objective of this study is to reconstruct a geographical distribution of IO, BrO, HCHO and (CHO)2 along the HaloCAST-P transect. The project will directly increase our knowledge on the distribution of these species in the open ocean environment.


Laminariae Emissions in Galicia: Observation by fLuorescence and Absorption Spectroscopy (LEGOLAS)

Endangered kelp forests play a key ecological role in the intertidal and submarine environment as habitat and feeding area for a wide variety of species. They also contribute to the stabilisation of sediments, to the primary production in the form of dissolved organic carbon, and to the nutrient cycle, being an important source of detritic material for the food chain in estuaries [Casal, 2007]. Besides this ecological role, molecular iodine emission from machroalgae is one of the most important contributions to the atmospheric active iodine species observed in the coastal marine boundary layer. The biogenic release of volatile organo-iodine compounds and molecular iodine are considered to be of great importance in ozone depletion events and new particle formation, with a potential impact on radiative forcing [Carpenter, 2003; von Glasow, 2005].
Laminariae, also know as kelp, is a genus of approximately 30 brown algal species. They occur in cold and mild Atlantic waters. Iodine bearing gas phase species related to kelp emissions have been observed in remote coastal locations as Mace Head (Ireland) [Saiz-Lopez and Plane, 2004; McFiggans, et al. 2004] and semi-polluted environments as in Roscoff (Francia) [Mahajan et al., 2009; Ball, et al., 2009].
In Galicia several species of Laminariae have been reported: Chorda filum (L.), Laminaria hyperborea (Gunner.) Foslie, Laminaria ochroleuca Pylaie, Laminaria saccharina (L.) Lamour y Saccorhiza polyschides (Light.) Batters. [Barbara & Cremades, 1993; Catoira et al, 1993; Pérez-Ruzafa et al., 2003].
To date, no study of atmospheric iodine species in the coast of Galicia has been reported. The objectives of LEGOLAS are two: first, detect quantitatively active iodine species in the coastal marine boundary layer and check their relevance on the local/regional atmospheric composition and climatology, and second, explore the long term potential of spectroscopic techniques for monitoring the health of the kelp forests through the observation of iodine species.





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