Composite analysis of impacts of dust aerosols on surface atmospheric variables and energy budgets in a semiarid region of China

Ling, Xiaolu; Guo, Weidong; Fu, Congbin

doi:10.1002/2013jd020274

Cited by 16 publications

(6 citation statements)

References 52 publications

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“…4) due to the strong reduction of the NET radiation reaching the ground by the mineral particles. Similar findings, under dust episode conditions, have been also reported by previous studies conducted for the Mediterranean (Pérez et al, 2006), across the Sahara (Helmert et al, 2007;Heinold et al, 2008;Stanelle et al, 2010) and in East Asia (Kumar et al, 2014;Ling et al, 2014). Over dust-affected maritime areas, due to the higher heat capacity of the sea, the temperature differences between the RADON and RADOFF experiments are almost negligible at these timescales.…”

Section: Impact On Temperature Fieldssupporting

confidence: 89%

“…6b) is identical to that of sensible heat fluxes; however, LE levels are remarkably lower than the regional averages of SH. This is attributed to the lower soil water content and limited evaporation in arid regions (Ling et al, 2014). Based on our simulations, LE values at noon gradually decrease both for the RADOFF (blue) and RADON (red) experiments over the forecast period, attributed to the too-moist initialization of the model (note that the model is initialized with FNL analysis produced by a different model; GFS).…”

Section: Impact On Sensible and Latent Heat Fluxesmentioning

confidence: 71%

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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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Section: Impact On Temperature Fieldssupporting

confidence: 89%

Section: Impact On Sensible and Latent Heat Fluxesmentioning

confidence: 71%

Direct radiative effects during intense Mediterranean desert dust outbreaks

et al. 2018

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“…An increasing trend from northwest to southeast (regional background color) and the frequency distribution of the ratios (bar chart) could be seen in Figure 2(a), indicated that PM 2.5 accounted for larger proportion of PM 10 in southeast districts compared to northwest districts. is phenomenon was consistent with the isohyetal line [59,60]. e lowest ratios in BNC (0.456) and MYR (0.480) suggested a contribution of more primary PM sources.…”

Section: Annual Variationssupporting

confidence: 83%

PM_2.5/PM₁₀ Ratios in Eight Economic Regions and Their Relationship with Meteorology in China

Zhao

Chen

et al. 2019

Advances in Meteorology

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China is suffering severe ambient air pollution in recent decades and particulate matter (PM) has become the major pollutant, especially for PM2.5 and PM10, which have highly raised scholars and policy-makers’ attention in last few years. The existing research has focused on the characteristics of PM2.5 and PM10, respectively, or analyzed the correlation between the two pollutants, while the ratio of PM2.5 to PM10 has been taken less consideration. In this study, daily mean PM2.5 and PM10 mass concentrations in 31 provincial capitals from 2014 to 2016 were used to present the temporal variations and spatial distribution of PM2.5/PM10 ratios among eight economic regions. And then, statistical method and correlation analysis were adopted to investigate the relationship between the ratios and AQI, the rate of change on the ratios, and the impact of meteorological parameters on the ratios. The results indicated that PM2.5/PM10 ratios showed an increasing trend from northwest to southeast due to different economic development and industrial types. The highest values were observed in winter among all regions, and the ratios on weekends were higher than that of on weekdays in most of the regions. Besides, domestic heating in northern China had a significant contribution to the ratios. Moreover, ratios had less changes, and the rate of change was stable in summer. As for air quality, the higher the ratio, the larger the possibility of high AQI so that the air pollution will be more severe. In terms of meteorological factors, the results demonstrated that relative humidity, precipitation, and pressure were the most important factors and had significantly positive impacts, while sunshine duration, temperature, and wind speed had negative effects on the ratios. The findings could identify the pollution sources among PM10 and be helpful for making regulation locally to reduce emission which considers anthropogenic sources and meteorological diffusion simultaneously.

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“…This long-lasting dust aerosol can perturb the energy balance of the Earth system through its direct radiative effects on solar and terrestrial radiation Ge et al, 2011Ge et al, , 2010Huang et al, 2014), indirect radiative effects via its influence on physical properties of clouds Lohmann and Feichter, 2005;Su et al, 2008), and semi-direct effects by heating the dust layer . Thus, high concentrations of elevated dust and its long-range transport from the Taklimakan may play an important role in climate and climate change Ling et al, 2014). To better understand dust emission, transport and the influence on climate will require more exploration of the local and mesoscale meteorological processes over this dust source region.…”

Section: Introductionmentioning

confidence: 99%

Taklimakan Desert nocturnal low-level jet: climatology and dust activity

Liu

Huang

et al. 2016

Atmos. Chem. Phys.

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Abstract. While nocturnal low-level jets (NLLJs) occur frequently in many parts of the world, the occurrence and other detailed characteristics of NLLJs over the Taklimakan Desert (TD) are not well known. This paper presents a climatology of NLLJs and coincident dust over the TD by analyzing multi-year ERA-Interim reanalysis and satellite observations. It is found that the ERA-Interim dataset can capture the NLLJs' features well by comparison with radiosonde data from two surface sites. The NLLJs occur in more than 60 % of nights, which are primarily easterly to east-northeasterly. They typically appear at 100 to 400 m above the surface with a speed of 4 to 10 m s −1 . Most NLLJs are located above the nocturnal inversion during the warm season, while they are embedded in the inversion layer during the cold season. NLLJs above the inversion have a strong annual cycle with a maximum frequency in August. We also quantify the convective boundary layer (CBL) height and construct an index to measure the magnitude of the momentum in the CBL. We find that the magnitude of momentum in the lower atmosphere from the top of the surface layer to the top of mixed layer is larger for NLLJ cases than for non-NLLJ cases, and in the warm season the downward momentum transfer process is more intense and rapid. The winds below the NLLJ core to the desert surface gain strength in summer and autumn, and these summer and autumn winds are coincident with an enhancement of aerosol optical depth. This indicates that the NLLJ is an important mechanism for dust activity and transport during the warm season over the Taklimakan.

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Composite analysis of impacts of dust aerosols on surface atmospheric variables and energy budgets in a semiarid region of China

Cited by 16 publications

References 52 publications

Direct radiative effects during intense Mediterranean desert dust outbreaks

Direct radiative effects during intense Mediterranean desert dust outbreaks

PM_2.5/PM₁₀ Ratios in Eight Economic Regions and Their Relationship with Meteorology in China

Taklimakan Desert nocturnal low-level jet: climatology and dust activity

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Composite analysis of impacts of dust aerosols on surface atmospheric variables and energy budgets in a semiarid region of China

Cited by 16 publications

References 52 publications

Direct radiative effects during intense Mediterranean desert dust outbreaks

Direct radiative effects during intense Mediterranean desert dust outbreaks

PM2.5/PM10 Ratios in Eight Economic Regions and Their Relationship with Meteorology in China

Taklimakan Desert nocturnal low-level jet: climatology and dust activity

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Product

Resources

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PM_2.5/PM₁₀ Ratios in Eight Economic Regions and Their Relationship with Meteorology in China