Estimation of mineral dust long-wave radiative forcing: sensitivity study to particle properties and application to real cases in the region of Barcelona

Sicard, Michaël; Bertolín, Santi; Mallet, M.; Dubuisson, Philippe; Comerón, Adolfo

doi:10.5194/acp-14-9213-2014

Cited by 67 publications

(148 citation statements)

References 82 publications

(131 reference statements)

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“…LW scattering has a stronger impact on LW F TOA than on F A and RMSE is 2.9 W m −2 and 0.1 W m −2 , respectively, between P and PA experiments. Similar results have been reported by Dufresne et al (2002) and Sicard et al (2014). The number of large particles in the size distribution might be potentially underestimated by Aeronet, and thus the impact of LW scattering could be underestimated.…”

Section: Solar Villagesupporting

confidence: 77%

Diurnal cycle of the dust instantaneous direct radiative forcing over the Arabian Peninsula

et al. 2015

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Abstract. In this study we attempted to better quantify radiative effects of dust over the Arabian Peninsula and their dependence on input parameters. For this purpose we have developed a stand-alone column radiation transport model coupled with the Mie, T-matrix and geometric optics calculations and driven by reanalysis meteorological fields and atmospheric composition. Numerical experiments were carried out for a wide range of aerosol optical depths, including extreme values developed during the dust storm on 18-20 March 2012. Comprehensive ground-based observations and satellite retrievals were used to estimate aerosol optical properties, validate calculations and carry out radiation closure. The broadband surface albedo, fluxes at the bottom and top of the atmosphere as well as instantaneous dust radiative forcing were estimated both from the model and observations. Diurnal cycle of the shortwave instantaneous dust direct radiative forcing was studied for a range of aerosol and surface characteristics representative of the Arabian Peninsula. Mechanisms and parameters responsible for diurnal variability of the radiative forcing were evaluated. We found that intrinsic variability of the surface albedo and its dependence on atmospheric conditions, along with anisotropic aerosol scattering, are mostly responsible for diurnal effects.

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Section: Solar Villagesupporting

confidence: 77%

Diurnal cycle of the dust instantaneous direct radiative forcing over the Arabian Peninsula

et al. 2015

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“…In the longwave (LW) spectral range, the aerosol radiative properties are usually estimated theoretically with a Mie code. The variable that contains the absorption and scattering quantities, the extinction coefficient, is normalized to the extinction coefficient in the shortwave (SW) spectral range, most of the time in the visible spectral range [Dufresne et al, 2002;Sicard et al, 2014], or to the number concentration [Sokolik et al, 1998]. As measurements of the extinction coefficient or its integral, the aerosol optical depth (AOD), are available in the SW spectral range, the equivalent extinction coefficient or AOD in the LW spectral range can be deduced thanks to that theoretical normalized extinction coefficient.…”

Section: Introductionmentioning

confidence: 99%

Separation of aerosol fine‐ and coarse‐mode radiative properties: Effect on the mineral dust longwave, direct radiative forcing

Sicard

Bertolín

Muñoz

et al. 2014

Geophysical Research Letters

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An improvement of the estimation of mineral dust longwave, direct radiative forcing is presented.It is based on recent developments that combine Sun photometer and multiwavelength lidar data to retrieve range-resolved coarse-and fine-mode extinction coefficients. The forcings are calculated separately for each mode, and their sum is compared to the classical approach in which only the total extinction is considered. The results of four cases of mineral dust intrusion in Barcelona, Spain, show that when the coarse mode predominates, the longwave forcings calculated with the classical approach are underestimated up to 20% near the surface. In all cases the strong coarse-mode predominance near the surface has also an effect on the forcing in the upper layers.

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“…Nevertheless, the signs of the DREs vary between the SW and LW spectrum (Osborne et al, 2011) as well as within the Earthatmosphere system. More specifically, due to the attenuation (through scattering and absorption) of the SW radiation, dust aerosols warm the atmosphere and cool the surface (Huang et al, 2014), while reverse tendencies are revealed at longer wavelengths attributed to the absorption and re-emission of LW radiation by the mineral particles (Sicard et al, 2014a). Between the two spectrum ranges, the SW DREs are larger compared to the LW ones, in absolute terms, thus explaining their predominance when the corresponding calculations are made for the NET (SW + LW) radiation (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Di Sarra et al, 2008;. Thus, a number of studies focused on Mediterranean dust outbreaks' impacts on the SW (Meloni et al, 2004;Gómez-Amoet al, 2011;Antón et al, 2012;Di Sarra et al, 2013;Obregón et al, 2015), LW (Antón et al, 2014;Sicard et al, 2014a) and NET Romano et al, 2016) radiation. However, the obtained results were representative at a local scale and, considering the high spatial variability of desert dust outbreaks, the optimum solution of assessing in a comprehensive way their impacts on weather and climate is provided by atmospheric-dust models.…”

Section: Introductionmentioning

confidence: 99%

Direct radiative effects during intense Mediterranean desert dust outbreaks

et al. 2018

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Abstract. The direct radiative effect (DRE) during 20 intense and widespread dust outbreaks, which affected the broader Mediterranean basin over the period March 2000-February 2013, has been calculated with the NMMB-MONARCH model at regional (Sahara and European continent) and shortterm temporal (84 h) scales. According to model simulations, the maximum dust aerosol optical depths (AODs) range from ∼ 2.5 to ∼ 5.5 among the identified cases. At midday, dust outbreaks locally induce a NET (shortwave plus longwave) strong atmospheric warming (DRE ATM values up to 285 W m −2 ; Niger-Chad; dust AODs up to ∼ 5.5) and a strong surface cooling (DRE NETSURF values down to −337 W m −2 ), whereas they strongly reduce the downward radiation at the ground level (DRE SURF values down to −589 W m −2 over the Eastern Mediterranean, for extremely high dust AODs, 4.5-5). During night-time, reverse effects of smaller magnitude are found. At the top of the atmosphere (TOA), positive (planetary warming) DREs up to 85 W m −2 are found over highly reflective surfaces (Niger-Chad; dust AODs up to ∼ 5.5) while negative (planetary cooling) DREs down to −184 W m −2 (Eastern Mediterranean; dust AODs 4.5-5) are computed over dark surfaces at noon. Dust outbreaks significantly affect the mean regional radiation budget, with NET DREs ranging from −8.5 to 0.5 W m −2 , from −31.6 to 2.1 W m −2 , from −22.2 to 2.2 W m −2 and from −1.7 to 20.4 W m −2 for TOA, SURF, NETSURF and ATM, respectively. Although the shortwave DREs are larger than the longwave ones, the latter are comparable or even larger at TOA, particularly over the Sahara at midday. As a response to the strong surface day-time cooling, dust outbreaks cause a reduction in the regional sensible and latent heat fluxes by up to 45 and 4 W m −2 , respectively, averaged over land areas of the simulation domain. Dust outbreaks reduce the temperature at 2 m by up to 4 K during day-time, whereas a reverse tendency of similar magnitude is found during nighttime. Depending on the vertical distribution of dust loads and time, mineral particles heat (cool) the atmosphere by up to 0.9 K (0.8 K) during day-time (night-time) within atmospheric dust layers. Beneath and above the dust clouds, mineral particles cool (warm) the atmosphere by up to 1.3 K (1.2 K) at noon (night-time). On a regional mean basis, negative feedbacks on the total emitted dust (reduced by 19.5 %) and dust AOD (reduced by 6.9 %) are found when dust interacts with the radiation. Through the consideration of dust radiative effects in numerical simulations, the model positive and negative biases for the downward surface SW or LW radiation, respectively, with respect to Baseline Surface Radiation Network (BSRN) measurements, are reduced. In addition, they also reduce the model near-surface (at 2 m) nocturnal cold biases by up to 0.5 K (regional averages), as well as the model warm biases at 950 and 700 hPa, where the dust concentration is maximized, by up to 0.4 K. However, improvements are relatively small and do not happen in all ...

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Estimation of mineral dust long-wave radiative forcing: sensitivity study to particle properties and application to real cases in the region of Barcelona

Cited by 67 publications

References 82 publications

Diurnal cycle of the dust instantaneous direct radiative forcing over the Arabian Peninsula

Diurnal cycle of the dust instantaneous direct radiative forcing over the Arabian Peninsula

Separation of aerosol fine‐ and coarse‐mode radiative properties: Effect on the mineral dust longwave, direct radiative forcing

Direct radiative effects during intense Mediterranean desert dust outbreaks

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