Air masses and aerosols chemical components in the free troposphere at the subtropical northeast atlantic region

Díaz, A. M.; Dı́az, J. P.; Expósito, Francisco J.; Hernandez-Leal, Pedro A.; Savoie, Dennis L.; Querol, Xavier

doi:10.1007/s10874-006-2644-5

Cited by 36 publications

(42 citation statements)

References 30 publications

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“…2a), while the AOD multi-year average is 0.2 ± 0.2 (hereafter, the errors are given as ±one standard deviation). North African mineral dust emissions are also frequent during the winter (December-February), reducing the activity during the spring (March-May) and the autumn (SeptemberNovember) (Prospero et al, 2002;Díaz et al, 2006). Nevertheless, the latter behavior is not clearly observed in the period studied in this work (Table 1 and Fig.…”

Section: Desert Dustmentioning

confidence: 66%

“…To a lesser extends, these stations can also be affected by anthropogenic aerosols from the European or African continent besides local pollution (Díaz et al, 2006;Rodríguez et al, 2011). Thus, the seasonality of the aerosol content in this region is dominated by mineral dust emissions from North Africa, achieving the maximal activity in summer (June-August).…”

Section: Desert Dustmentioning

confidence: 99%

“…An AOD average of 0.1 ± 0.1 is obtained in this time period in contrast to 0.02 ± 0.01 recorded during the rest of the year, which approaches the multi-year AOD mean of MLO, 0.04 ± 0.01. This seasonality is governed by the regional meteorological conditions (Azores High and North African Low), which also affect the regions 1 and 2 (Díaz et al, 2006;García et al, 2009). Therefore, the winter can be considered as representative of free troposphere conditions (AOD season mean of 0.03 ± 0.02) to estimate the aerosol radiative forcing in this region.…”

Section: Free Tropospherementioning

confidence: 99%

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Shortwave radiative forcing and efficiency of key aerosol types using AERONET data

et al. 2012

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Abstract. The shortwave radiative forcing ( F ) and the radiative forcing efficiency ( F eff ) of natural and anthropogenic aerosols have been analyzed using estimates of radiation both at the Top (TOA) and at the Bottom Of Atmosphere (BOA) modeled based on AERONET aerosol retrievals. Six main types of atmospheric aerosols have been compared (desert mineral dust, biomass burning, urbanindustrial, continental background, oceanic and free troposphere) in similar observational conditions (i.e., for solar zenith angles between 55 • and 65 • ) in order to compare the nearly same solar geometry. The instantaneous F averages obtained vary from −122 ± 37 Wm −2 (aerosol optical depth, AOD, at 0.55 µm, 0.85 ± 0.45) at the BOA for the mixture of desert mineral dust and biomass burning aerosols in West Africa and −42 ± 22 Wm −2 (AOD = 0.9 ± 0.5) at the TOA for the pure mineral dust also in this region up to −6 ± 3 Wm −2 and −4 ± 2 Wm −2 (AOD = 0.03 ± 0.02) at the BOA and the TOA, respectively, for free troposphere conditions. This last result may be taken as reference on a global scale. Furthermore, we observe that the more absorbing aerosols are overall more efficient at the BOA in contrast to at the TOA, where they backscatter less solar energy into the space. The analysis of the radiative balance at the TOA shows that, together with the amount of aerosols and their absorptive capacity, it is essential to consider the surface albedo of the region on which they are. Thus, we document that in regions with high surface reflectivity (deserts and snow conditions) atmospheric aerosols lead to a warming of the Earthatmosphere system.

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Section: Desert Dustmentioning

confidence: 66%

Section: Desert Dustmentioning

confidence: 99%

Section: Free Tropospherementioning

confidence: 99%

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Shortwave radiative forcing and efficiency of key aerosol types using AERONET data

et al. 2012

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“…García et al, 2012a, and references therein). During wintertime, the Saharan events rarely reach the IZO altitude, since they are confined below 2 km of altitude (Díaz et al, 2006;Alonso-Pérez et al, 2011, and references therein). Within the IZO's atmospheric research activities, the ground-based FTS measurements started in 1999 and continue until the present with two Bruker IFS spectrometers (an IFS 120M from 1999 to 2005 and an IFS 120/5HR from 2005 until present).…”

Section: Introductionmentioning

confidence: 99%

Consistency and quality assessment of the Metop-A/IASI and Metop-B/IASI operational trace gas products (O3, CO, N2O, CH4, and CO2) in the subtropical North Atlantic

et al. 2016

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Abstract. This paper presents the tools and methodology for performing a routine comprehensive monitoring of consistency and quality of IASI (Infrared Atmospheric Sounding Interferometer) trace gas Level 2 (L2) products (O 3 , CO, N 2 O, CH 4 , and CO 2 ) generated at EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites) using ground-based observations at the Izaña Atmospheric Observatory (IZO, Tenerife). As a demonstration the period 2010-2014 was analysed, covering the version 5 of the IASI L2 processor. Firstly, we assess the consistency between the total column (TC) observations from the IASI sensors on board the EUMETSAT Metop-A and Metop-B meteorological satellites (IASI-A and IASI-B respectively) in the subtropical North Atlantic region during the first 2 years of IASI-B operations (2012)(2013)(2014). By analysing different timescales, we probe the daily and annual consistency of the variability observed by IASI-A and IASI-B and thereby assess the suitability of IASI-B for continuation of the IASI-A time series. The continuous intercomparison of both IASI sensors also offers important diagnostics for identifying inconsistencies between the data records and for documenting their temporal stability. Once the consistency of IASI sensors is documented we estimate the overall accuracy of all the IASI trace gas TC products by comparing to coincident ground-based Fourier transform infrared spectrometer (FTS) measurements performed at IZO from 2010 to 2014. The IASI L2 products reproduce the ground-based FTS observations well at the longest temporal scales, i.e. annual cycles and long-term trends for all the trace gases considered (Pearson correlation coefficient, R, larger than 0.95 and 0.75 for long-term trends and annual cycles respectively) with the exception of CO 2 . For CO 2 acceptable agreement is only achieved for long-term trends (R ∼ 0.70). The differences observed between IASI and FTS observations can be in part attributed to the different vertical sensitivities of the two remote sensing instruments and also to the degree of maturity of the IASI products: O 3 and CO are pre-operational, while N 2 O, CH 4 , and CO 2 are, for the period covered by this study, aspirational products only and are not considered mature. Regarding shorter timescales (single or daily measurements), only the O 3 product seems to show good sensitivity to actual atmospheric variations (R ∼ 0.80), while the CO product is only moderately sensitive (R ∼ 0.50). For the remainder of the trace gases, further improvements would be required to capture the day-to-day real atmospheric variability.

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“…Only measurements at Mauna Loa Observatory (Weber and McMurry, 1996), at Izana (Diaz et al, 2006;Rodriguez et al, 2009) and from ABC-PYRAMID station in Himalaya (Bonasoni et al, 2008) deliver long-term information from outer tropics and subtropics. Outside of the tropical regions, there are several well established observatories with long-term aerosol measurements.…”

Section: Introductionmentioning

confidence: 99%

Analysis of number size distributions of tropical free tropospheric aerosol particles observed at Pico Espejo (4765 m a.s.l.), Venezuela

et al. 2011

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Abstract. The first long-term measurements of aerosol number and size distributions in South-American tropical free troposphere (FT) were performed from March 2007 until March 2009. The measurements took place at the high altitude Atmospheric Research Station Alexander von Humboldt. The station is located on top of the Sierra Nevada mountain ridge at 4765 m a.s.l. nearby the city of Mérida, Venezuela. Aerosol size distribution and number concentration data was obtained with a custom-built Differential Mobility Particle Sizer (DMPS) system and a Condensational Particle Counter (CPC). The analysis of the annual and diurnal variability of the tropical FT aerosol focused mainly on possible links to the atmospheric general circulation in the tropics. Considerable annual and diurnal cycles of the particle number concentration were observed. Highest total particle number concentrations were measured during the dry season (January-March, 519 ± 613 cm −3 ), lowest during the wet season (July-September, 318 ± 194 cm −3 ). The more humid FT (relative humidity (RH) range 50-95 %) contained generally higher aerosol particle number concentrations (573 ± 768 cm −3 during dry season, 320 ± 195 cm −3 during wet season) than the dry FT (RH < 50 %, 454 ± 332 cm −3 during dry season, 275 ± 172 cm −3 during wet season), indicating the importance of convection for aerosol distributions in the tropical FT. The diurnal cycle in the variability of the particle number concentration was mainly driven by local orography.

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Air masses and aerosols chemical components in the free troposphere at the subtropical northeast atlantic region

Cited by 36 publications

References 30 publications

Shortwave radiative forcing and efficiency of key aerosol types using AERONET data

Shortwave radiative forcing and efficiency of key aerosol types using AERONET data

Consistency and quality assessment of the Metop-A/IASI and Metop-B/IASI operational trace gas products (O<sub>3</sub>, CO, N<sub>2</sub>O, CH<sub>4</sub>, and CO<sub>2</sub>) in the subtropical North Atlantic

Analysis of number size distributions of tropical free tropospheric aerosol particles observed at Pico Espejo (4765 m a.s.l.), Venezuela

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Air masses and aerosols chemical components in the free troposphere at the subtropical northeast atlantic region

Cited by 36 publications

References 30 publications

Shortwave radiative forcing and efficiency of key aerosol types using AERONET data

Shortwave radiative forcing and efficiency of key aerosol types using AERONET data

Consistency and quality assessment of the Metop-A/IASI and Metop-B/IASI operational trace gas products (O&lt;sub&gt;3&lt;/sub&gt;, CO, N&lt;sub&gt;2&lt;/sub&gt;O, CH&lt;sub&gt;4&lt;/sub&gt;, and CO&lt;sub&gt;2&lt;/sub&gt;) in the subtropical North Atlantic

Analysis of number size distributions of tropical free tropospheric aerosol particles observed at Pico Espejo (4765 m a.s.l.), Venezuela

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Product

Resources

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Consistency and quality assessment of the Metop-A/IASI and Metop-B/IASI operational trace gas products (O<sub>3</sub>, CO, N<sub>2</sub>O, CH<sub>4</sub>, and CO<sub>2</sub>) in the subtropical North Atlantic