Juan Carlos Gómez Martı́n

Instituto de Astrofísica de Andalucía

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

J. M. C. Plane

University of Leeds

Alfonso Saiz‐Lopez

Consejo Superior de Investigaciones Científicas

Olga Muñoz

Instituto de Astrofísica de Andalucía

Anoop S. Mahajan

Indian Institute of Tropical Meteorology

Wuhu Feng

National Centre for Atmospheric Science

Teresa Jardiel

Instituto de Cerámica y Vidrio

Julia Martikainen

Instituto de Astrofísica de Andalucía

M. Peiteado

Instituto de Cerámica y Vidrio

Carlos A. Cuevas

Instituto de Química Física Blas Cabrera

Rafael P. Fernández

Consejo Nacional de Investigaciones Científicas y Técnicas

Cooperative Institutions

University of Leeds

Consejo Superior de Investigaciones Científicas

Centre National de la Recherche Scientifique

University of Colorado Boulder

Cooperative Institute for Research in Environmental Sciences

National Centre for Atmospheric Science

Instituto de Astrofísica de Andalucía

Instituto de Química Física Blas Cabrera

NSF National Center for Atmospheric Research

National Oceanic and Atmospheric Administration

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Modeling the Formation of Tropical Rings of Atomic Bromine and Iodine

2014 AGU Fall Meeting (2014)

Alfonso Saiz‐Lopez R. Fernandez R. J. Salawitch D. E. Kinnison Jean‐François Lamarque

Source

Cite

Citations (0)

High-speed optical analysis of microscopic particles

STIN (1974)

J. M. Crowell G.C. Salzman P. F. Mullaney Juan Carlos Gómez Martı́n

Source

Cite

Citations (4)

Are iodic acid measurements by chemical ionization unambiguous?  

THOMAS L. LEWIS Juan Carlos Gómez Martı́n Mark A. Blitz Alfonso Saiz‐Lopez J. M. C. Plane

Field observations of IO3&#8722; and HIO3&#8722;-containing cluster anions by chemical ionization&#8211;atmospheric pressure interface&#8211;time-of-flight mass spectrometry (CI-API-ToF-MS) have been reported1. These observations, which employ nitrate (NO3&#8722;) reagent ions for reaction with the analytes, have been interpreted as resulting from atmospheric gas-phase iodic acid (HOIO2) and molecular cluster formation via HOIO2 addition steps. CI-API-ToF-MS chamber measurements with alternative ionization schemes have also reported signals that could be attributed to gas-phase HOIO and HOIO2. However, well-established chemical kinetics and thermochemistry do not indicate any straightforward route to gas-phase iodine oxyacids and HOIO2 particle formation in the atmosphere. This does not only hinder the ability of chemical models for linking iodine emissions and particle formation, but also calls into question the interpretation of these CI-API-ToF-MS measurements. It has been proposed that water plays an important role in generating gas phase and HOIO2-containing molecular clusters, but recent flow tube experiments have established extremely low upper limits to the rate constants of possible reactions between iodine oxides (IOx and IxOy) and water. In this presentation, we discuss experimental and theoretical kinetics and thermochemistry of proposed routes to gas-phase HOIO and HOIO2&#160;in the atmosphere as well as potential ion-molecule reactions turning iodine oxides into IO3- ions in the CI-API-ToF-MS inlet. We show that there is an important ambiguity in the interpretation of IO3- and other signals observed with CI instruments as a result of barrierless reactions between IxOy and the reagent ions. Experiments for solving this ambiguity and reconciling conflicting results are proposed.

Adenine nucleotide

10.5194/egusphere-egu21-13817

Cite

Citations (0)

On the application of scattering matrix measurements to detection and identification of major types of airborne aerosol particles: Volcanic ash, desert dust and pollen

Journal of Quantitative Spectroscopy and Radiative Transfer (2021)

Juan Carlos Gómez Martı́n D. Guirado E. Frattin María Bermúdez-Edo Paloma Cariñanos

Atmospheric aerosols play key roles in climate and have important impacts on human activities and health. Hence, much effort is directed towards developing methods of improved detection and discrimination of different types of aerosols. Among these, light scattering-based detection of aerosol offers several advantages including applications in both in situ and remote sensing devices. In this work, new scattering matrix measurements for two samples of airborne desert dust collected in Spain and China are reported. The average extrapolated scattering matrices of airborne desert dust and of volcanic ash at two wavelengths have been calculated and compared with the aim of finding criteria to distinguish these two types of aerosol. Additionally, the scattering matrix of cypress pollen has been measured and extrapolated to explore differences with mineral dust that can be exploited in atmospheric detection. Field measurements of the backscattering linear depolarization ratio δL(180°) are used to obtain information about non-sphericity and discrimination between fine and coarse aerosol. However, the average δL(180°) for the three types of aerosols considered in this work in the visible spectral range is δL(180°) = 0.40 ± 0.05. This shows that δL(180°) is not informative about the composition or morphology of irregular particles. By contrast, measurements of scattering matrix elements or depolarization ratios at different scattering angles may provide information about the structural differences of particles, and in particular may enable to differentiate airborne volcanic ash from desert dust, which are otherwise similar in terms of size and optical constants. Cypress pollen shows a characteristic degree of linear polarization curve that is very different from that of polydisperse irregular mineral dust. Light scattering field instruments and remote sensing methods could extract more information about the characteristics of aerosol particles if modifications were introduced to measure the phase curves of several scattering matrix elements or depolarization ratios.

Mineral dust

Volcanic ash

Mueller calculus

Matrix (chemical analysis)

10.1016/j.jqsrt.2021.107761

Cite

Citations (35)

Response to Reviewer 2

Juan Carlos Gómez Martı́n

10.5194/acp-2020-456-ac2

Cite

Citations (0)

Response to Reviewer 3

Juan Carlos Gómez Martı́n

10.5194/acp-2020-456-ac3

Cite

Citations (0)

Enhanced production of oxidised mercury over the tropical Pacific Ocean: a key missing oxidation pathway

Atmospheric chemistry and physics (2014)

Fei Wang Alfonso Saiz‐Lopez Anoop S. Mahajan Juan Carlos Gómez Martı́n Debbie Armstrong

Abstract. Mercury is a contaminant of global concern. It is transported in the atmosphere primarily as gaseous elemental mercury, but its reactivity and deposition to the surface environment, through which it enters the aquatic food chain, is greatly enhanced following oxidation. Measurements and modelling studies of oxidised mercury in the polar to sub-tropical marine boundary layer (MBL) have suggested that photolytically produced bromine atoms are the primary oxidant of mercury. We report year-round measurements of elemental and oxidised mercury, along with ozone, halogen oxides (IO and BrO) and nitrogen oxides (NO2), in the MBL over the Galápagos Islands in the equatorial Pacific. Elemental mercury concentration remained low throughout the year, while higher than expected levels of oxidised mercury occurred around midday. Our results show that the production of oxidised mercury in the tropical MBL cannot be accounted for by bromine oxidation only, or by the inclusion of ozone and hydroxyl. As a two-step oxidation mechanism, where the HgBr intermediate is further oxidised to Hg(II), depends critically on the stability of HgBr, an additional oxidant is needed to react with HgBr to explain more than 50% of the observed oxidised mercury. Based on best available thermodynamic data, we show that atomic iodine, NO2, or HO2 could all play the potential role of the missing oxidant, though their relative importance cannot be determined explicitly at this time due to the uncertainties associated with mercury oxidation kinetics. We conclude that the key pathway that significantly enhances atmospheric mercury oxidation and deposition to the tropical oceans is missing from the current understanding of atmospheric mercury oxidation.

Mercury

Elemental mercury

10.5194/acp-14-1323-2014

Cite

Citations (95)

Supplementary material to "A new model of meteoric calcium in the mesosphere and lower thermosphere"

J. M. C. Plane Wuhu Feng Juan Carlos Gómez Martı́n Michael Gerding S. Raizada

10.5194/acp-2018-493-supplement

Cite

Citations (0)

Iodine chemistry in the eastern Pacific marine boundary layer

Journal of Geophysical Research Atmospheres (2013)

Juan Carlos Gómez Martı́n Anoop S. Mahajan T. Hay Cristina Prados‐Román Carlos Ordóñez

Observations of gas‐phase iodine species were made during a field campaign in the eastern Pacific marine boundary layer (MBL). The Climate and Halogen Reactivity Tropical Experiment (CHARLEX) in the Galápagos Islands, running from September 2010 to present, is the first long‐term ground‐based study of trace gases in this region. Observations of gas‐phase iodine species were made using long‐path differential optical absorption spectroscopy (LP‐DOAS), multi‐axis DOAS (MAX‐DOAS), and resonance and off‐resonance fluorescence by lamp excitation (ROFLEX). These measurements were supported by ancillary measurements of ozone, nitrogen oxides, and meteorological variables. Selective halocarbon and ultrafine aerosol concentration measurements were also made. MAX‐DOAS observations of iodine monoxide (IO) display a weak seasonal variation. The maximum differential slant column density was 3.8 × 10 13 molecule cm −2 (detection limit ~7 × 10 12 molecule cm −2 ). The seasonal variation of reactive iodine IO x (= I + IO) is stronger, peaking at 1.6 pptv during the warm season (February–April). This suggests a dependence of the iodine sources on the annual cycle in sea surface temperature, although perturbations by changes in ocean surface iodide concentration and solar radiation are also possible. An observed negative correlation of IO x with chlorophyll‐ a indicates a predominance of abiotic sources. The low IO mixing ratios measured (below the LP‐DOAS detection limit of 0.9 pptv) are not consistent with satellite observations if IO is confined to the MBL. The IO x loading is consistent with the observed absence of strong ozone depletion and nucleation events, indicating a small impact of iodine chemistry on these climatically relevant factors in the eastern Pacific MBL.

Trace gas

Mixing ratio

10.1002/jgrd.50132

Cite

Citations (70)

Spatial and temporal variability of iodine in aerosol

Juan Carlos Gómez Martı́n Alfonso Saiz‐Lopez Carlos A. Cuevas Rafael P. Fernández Benjamin Gilfedder

In this work we describe the compilation and homogenization of an extensive dataset of aerosol total iodine field observations in the period between 1963 and 2018 and we discuss its spatial and temporal trends. Total iodine in aerosol shows a distinct latitudinal dependence, with an enhancement towards the northern hemisphere (NH) tropics and lower values towards the poles. Longitudinally, there is some indication of a wave-one profile in the Tropics, which peaks in the Atlantic and shows a minimum in the Pacific, following the well-known wave-one longitudinal variation of tropical tropospheric ozone. These spatial trends result from the global distribution of the main oceanic iodine source to the atmosphere (the reaction of surface ozone with aqueous iodide on the sea water-air interface). New data from Antarctica show that the south polar seasonal variation of iodine in aerosol mirrors that observed previously in the Arctic, with two equinoctial maxima and the dominant maximum occurring in spring. While no clear seasonal variability is observed in NH middle latitudes, there is an indication of different seasonal cycles in the NH tropical Atlantic and Pacific. A weak positive long-term trend is observed in the tropical annual averages, which is consistent with an enhancement of the anthropogenic ozone-driven global oceanic source of iodine over the last 50 years.

Tropical Atlantic

10.5194/egusphere-egu21-2077

Cite

Citations (7)