Wildfire particulate matter in Europe during summer 2003: meso-scale modeling of smoke emissions, transport and radiative effects

Abstract. The present study investigates effects of wildfire emissions on air quality in Europe during an intense fire season that occurred in summer 2003. A meso-scale chemistry transport model CHIMERE is used, together with ground based and satellite aerosol optical measurements, to assess the dispersion of fire emissions and to quantify the associated radiative effects. The model has been improved to take into account the MODIS daily smoke emission inventory as well as the injection altitude of smoke particles. The simulated aerosol optical properties are inputted into a radiative transfer model to estimate (off-line) the effects of smoke particles on photolysis rates and atmospheric radiative forcing. We have found that wildfires generated comparable amounts of primary aerosol pollutants (220 kTons of PM2.5, fine particles) to anthropogenic sources during August 2003, and caused significant changes in aerosol optical properties not only close to the fire source regions, but also over a large part of Europe as a result of the long-range transport of smoke. Including these emissions into the model significantly improved its performance in simulating observed aerosol concentrations and optical properties. Quantitative comparison with MODIS and POLDER data during the major fire event (3–8 August) showed the ability of the model to reproduce high aerosol optical thickness (AOT) over Northern Europe caused by the advection of the smoke plume from the Portugal source region. Statistical analyses of model simulations showed a better agreement with observed AOT data at AERONET ground stations and suggest that wildfire emissions are responsible for a 30% enhancement in mean AOT values during the heat-wave episode. The implications for air quality over a large part of Europe are significant during this episode. First, directly, the modeled wildfire emissions caused an increase in average PM10 ground concentrations from 20 to 200%. The largest enhancement in PM10 concentrations stayed however confined within a 200 km area around the fire source locations and reached up to 40 μ g/m3. Second, indirectly, the presence of elevated smoke layers over Europe significantly altered atmospheric radiative properties: the model results imply a 10 to 30% decrease in photolysis rates and an increase in atmospheric radiative forcing of 10–35 Wm−2 during the period of strong fire influence throughout a large part of Europe. These results suggest that sporadic wildfire events may have significant effects on regional photochemistry and atmospheric stability, and need to be considered in current chemistry-transport models.

Download Full-text

Wildfire particulate matter in Europe during summer 2003: meso-scale modeling of smoke emissions, transport and radiative effects

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-4043-2007 ◽

2007 ◽

Vol 7 (15) ◽

pp. 4043-4064 ◽

Cited By ~ 151

Author(s):

A. Hodzic ◽

S. Madronich ◽

B. Bohn ◽

S. Massie ◽

L. Menut ◽

...

Keyword(s):

Optical Properties ◽

Air Quality ◽

Radiative Forcing ◽

Anthropogenic Sources ◽

Radiative Effects ◽

Aerosol Optical Properties ◽

Smoke Particles ◽

Fire Source ◽

Photolysis Rates ◽

Meso Scale

Abstract. The present study investigates effects of wildfire emissions on air quality in Europe during an intense fire season that occurred in summer 2003. A meso-scale chemistry transport model CHIMERE is used, together with ground based and satellite aerosol optical measurements, to assess the dispersion of fire emissions and to quantify the associated radiative effects. The model has been improved to take into account a MODIS-derived daily smoke emission inventory as well as the injection altitude of smoke particles. The simulated aerosol optical properties are put into a radiative transfer model to estimate (off-line) the effects of smoke particles on photolysis rates and atmospheric radiative forcing. We have found that the simulated wildfires generated comparable amounts of primary aerosol pollutants (130 kTons of PM2.5, fine particles) to anthropogenic sources during August 2003, and caused significant changes in aerosol optical properties not only close to the fire source regions, but also over a large part of Europe as a result of the long-range transport of the smoke. Including these emissions into the model significantly improved its performance in simulating observed aerosol concentrations and optical properties. Quantitative comparison with MODIS and POLDER data during the major fire event (3–8 August 2003) showed the ability of the model to reproduce high aerosol optical thickness (AOT) over Northern Europe caused by the advection of the smoke plume from the Portugal source region. Although there was a fairly good spatial agreement with satellite data (correlation coefficients ranging from 0.4 to 0.9), the temporal variability of AOT data at specific AERONET locations was not well captured by the model. Statistical analyses of model-simulated AOT data at AERONET ground stations showed a significant decrease in the model biases suggesting that wildfire emissions are responsible for a 30% enhancement in mean AOT values during the heat-wave episode. The implications for air quality over a large part of Europe are significant during this episode. First, directly, the modeled wildfire emissions caused an increase in average PM2.5 ground concentrations from 20 to 200%. The largest enhancement in PM2.5 concentrations stayed, however, confined within a 200 km area around the fire source locations and reached up to 40 μg/m³. Second, indirectly, the presence of elevated smoke layers over Europe significantly altered atmospheric radiative properties: the model results imply a 10 to 30% decrease in photolysis rates and an increase in atmospheric radiative forcing of 10–35 W m−2 during the period of strong fire influence throughout a large part of Europe. These results suggest that sporadic wildfire events may have significant effects on regional photochemistry and atmospheric stability, and need to be considered in current chemistry-transport models.

Download Full-text

Interactive Aerosol Feedbacks on Photolysis Rates in the GEM-MACH Air Quality Model for an Athabasca Oil-Sands Modelling Study

10.5194/egusphere-egu2020-10470 ◽

2020 ◽

Author(s):

Mahtab Majdzadeh ◽

Craig Stroud ◽

Ayodeji Akingunola ◽

Paul Makar ◽

Christopher Sioris ◽

...

Keyword(s):

Optical Properties ◽

Air Quality ◽

Radiative Transfer ◽

Forest Fire ◽

Lookup Table ◽

Aerosol Optical Properties ◽

Extinction Efficiency ◽

Scattering Cross ◽

Photolysis Rates ◽

On Line

The radiative transfer module of an on-line chemical transport models requires input data from aerosol extinction efficiency, single scatter albedo and asymmetry factor, in order to predict the radiative state of the atmosphere. These aerosol optical properties (aerosol optical depth, AOD), may be integrated vertically for comparison to satellite observations. These optical effects may also influence the shorter wavelengths associated with atmospheric gas photolysis, influencing atmospheric reactivity. These processes may be harmonized in an on-line reaction transport model, such as Environment and Climate Change Canada&#8217;s GEM-MACH (GEM: Global Environmental Multi-scale &#8211; MACH: Modelling Air quality and Chemistry). Previous photolysis routine in the radiative transfer module, MESSY-JVAL (Modular Earth Sub-Model System), in GEM-MACH, made use of a climatology of aerosol optical properties, and the previous on-line version made use of a homogeneous mixture Mie code for meteorological radiative transfer calculations.We calculated a new lookup table for the extinction efficiency, absorption and scattering cross sections of each aerosol type. The new version of MESSY-JVAL uses GEM-MACH predicted aerosol size distributions, chemical composition and relative humidity in each vertical column at each time step as input, reads aerosol absorption and scattering cross section data from the new lookup table and calculates aerosol optical properties, that are then used to modify both photolysis and meteorological radiative transfer calculations.In order to evaluate these modifications to the model, we performed a series of simulations with GEM-MACH with wildfire emissions inputs from the Canadian Forest Fire Emissions Prediction System (CFFEPS) and compared the model AOD output with satellite and AERONET (Aerosol Robotic Network) measurement data. Comparison of the hourly AERONET and monthly-averaged satellite AOD demonstrates major improvements in the revised model AOD predictions. The impact of the updated photolysis rates and meteorological radiative transfer calculations on predictions of oxidant mixing ratios and rates of pollutant oxidation (nitrogen dioxide conversion to nitric acid) will be assessed both within and below the forest fire plume.

Download Full-text

Sensitivity of aerosol radiative effects to different mixing assumptions in the AEROPT 1.0 submodel of the EMAC atmospheric-chemistry–climate model

Geoscientific Model Development ◽

10.5194/gmd-7-2503-2014 ◽

2014 ◽

Vol 7 (5) ◽

pp. 2503-2516 ◽

Cited By ~ 23

Author(s):

K. Klingmüller ◽

B. Steil ◽

C. Brühl ◽

H. Tost ◽

J. Lelieveld

Keyword(s):

Optical Properties ◽

Radiative Transfer ◽

Black Carbon ◽

Atmospheric Chemistry ◽

Radiative Forcing ◽

Climate Model ◽

Mixing Rule ◽

Aerosol Optical Properties ◽

Internal Mixing ◽

Aerosol Radiative

Abstract. The modelling of aerosol radiative forcing is a major cause of uncertainty in the assessment of global and regional atmospheric energy budgets and climate change. One reason is the strong dependence of the aerosol optical properties on the mixing state of aerosol components, such as absorbing black carbon and, predominantly scattering sulfates. Using a new column version of the aerosol optical properties and radiative-transfer code of the ECHAM/MESSy atmospheric-chemistry–climate model (EMAC), we study the radiative transfer applying various mixing states. The aerosol optics code builds on the AEROPT (AERosol OPTical properties) submodel, which assumes homogeneous internal mixing utilising the volume average refractive index mixing rule. We have extended the submodel to additionally account for external mixing, partial external mixing and multilayered particles. Furthermore, we have implemented the volume average dielectric constant and Maxwell Garnett mixing rule. We performed regional case studies considering columns over China, India and Africa, corroborating much stronger absorption by internal than external mixtures. Well-mixed aerosol is a good approximation for particles with a black-carbon core, whereas particles with black carbon at the surface absorb significantly less. Based on a model simulation for the year 2005, we calculate that the global aerosol direct radiative forcing for homogeneous internal mixing differs from that for external mixing by about 0.5 W m−2.

Download Full-text

A new radiation infrastructure for the Modular Earth Submodel System (MESSy, based on version 2.51)

10.5194/gmd-2015-277 ◽

2016 ◽

Cited By ~ 1

Author(s):

Simone Dietmüller ◽

Patrick Jöckel ◽

Holger Tost ◽

Markus Kunze ◽

Cathrin Gellhorn ◽

...

Keyword(s):

Optical Properties ◽

Atmospheric Chemistry ◽

Radiative Forcing ◽

General Circulation ◽

Circulation Model ◽

Shortwave Radiation ◽

Aerosol Optical Properties ◽

On Line ◽

User Friendly ◽

Radiation Scheme

Abstract. The Modular Earth Submodel System (MESSy) provides an interface to couple submodels to a basemodel via a highly flexible data management facility (Jöckel et al., 2010). In the present paper we present the four new radiation related submodels RAD, AEROPT, CLOUDOPT and ORBIT. The submodel RAD (with shortwave radiation scheme RAD_FUBRAD) simulates the radiative transfer, the submodel AEROPT calculates the aerosol optical properties, the submodel CLOUDOPT calculates the cloud optical properties, and the submodel ORBIT is responsible for Earth orbit calculations. These submodels are coupled via the standard MESSy infrastructure and are largely based on the original radiation scheme of the general circulation model ECHAM5, however, expanded with additional features. These features comprise, among others, user-friendly and flexibly controllable (by namelists) on-line radiative forcing calculations by multiple diagnostic calls of the radiation routines. With this, it is now possible to calculate radiative forcing (instantaneous as well as stratosphere adjusted) of various greenhouse gases simultaneously in only one simulation, as well as the radiative forcing of cloud perturbations. Examples of on-line radiative forcing calculations in the ECHAM/MESSy Atmospheric Chemistry (EMAC) model are presented.

Download Full-text

Intercomparison of biomass burning aerosol optical properties from in situ and remote-sensing instruments in ORACLES-2016

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-9181-2019 ◽

2019 ◽

Vol 19 (14) ◽

pp. 9181-9208 ◽

Cited By ~ 16

Author(s):

Kristina Pistone ◽

Jens Redemann ◽

Sarah Doherty ◽

Paquita Zuidema ◽

Sharon Burton ◽

...

Keyword(s):

Optical Properties ◽

Case Studies ◽

Biomass Burning ◽

Radiative Forcing ◽

Measurement Techniques ◽

Single Scattering ◽

Single Scattering Albedo ◽

Aerosol Optical Properties ◽

Biomass Burning Aerosol

Abstract. The total effect of aerosols, both directly and on cloud properties, remains the biggest source of uncertainty in anthropogenic radiative forcing on the climate. Correct characterization of intensive aerosol optical properties, particularly in conditions where absorbing aerosol is present, is a crucial factor in quantifying these effects. The southeast Atlantic Ocean (SEA), with seasonal biomass burning smoke plumes overlying and mixing with a persistent stratocumulus cloud deck, offers an excellent natural laboratory to make the observations necessary to understand the complexities of aerosol–cloud–radiation interactions. The first field deployment of the NASA ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) campaign was conducted in September of 2016 out of Walvis Bay, Namibia. Data collected during ORACLES-2016 are used to derive aerosol properties from an unprecedented number of simultaneous measurement techniques over this region. Here, we present results from six of the eight independent instruments or instrument combinations, all applied to measure or retrieve aerosol absorption and single-scattering albedo. Most but not all of the biomass burning aerosol was located in the free troposphere, in relative humidities typically ranging up to 60 %. We present the single-scattering albedo (SSA), absorbing and total aerosol optical depth (AAOD and AOD), and absorption, scattering, and extinction Ångström exponents (AAE, SAE, and EAE, respectively) for specific case studies looking at near-coincident and near-colocated measurements from multiple instruments, and SSAs for the broader campaign average over the month-long deployment. For the case studies, we find that SSA agrees within the measurement uncertainties between multiple instruments, though, over all cases, there is no strong correlation between values reported by one instrument and another. We also find that agreement between the instruments is more robust at higher aerosol loading (AOD400>0.4). The campaign-wide average and range shows differences in the values measured by each instrument. We find the ORACLES-2016 campaign-average SSA at 500 nm (SSA500) to be between 0.85 and 0.88, depending on the instrument considered (4STAR, AirMSPI, or in situ measurements), with the interquartile ranges for all instruments between 0.83 and 0.89. This is consistent with previous September values reported over the region (between 0.84 and 0.90 for SSA at 550nm). The results suggest that the differences observed in the campaign-average values may be dominated by instrument-specific spatial sampling differences and the natural physical variability in aerosol conditions over the SEA, rather than fundamental methodological differences.

Download Full-text

Seasonal variation of columnar aerosol optical properties and radiative forcing over Beijing, China

Atmospheric Environment ◽

10.1016/j.atmosenv.2017.07.011 ◽

2017 ◽

Vol 166 ◽

pp. 340-350 ◽

Cited By ~ 18

Author(s):

Xingna Yu ◽

Rui Lü ◽

Chao Liu ◽

Liang Yuan ◽

Yixing Shao ◽

...

Keyword(s):

Optical Properties ◽

Seasonal Variation ◽

Radiative Forcing ◽

Aerosol Optical Properties ◽

Beijing China

Download Full-text

Interannual Variations of Summer Monsoons: Sensitivity to Cloud Radiative Forcing

Journal of Climate ◽

10.1175/1520-0442-11.8.1883 ◽

1998 ◽

Vol 11 (8) ◽

pp. 1883-1905 ◽

Cited By ~ 8

Author(s):

O. P. Sharma ◽

H. Le Treut ◽

G. Sèze ◽

L. Fairhead ◽

R. Sadourny

Keyword(s):

Optical Properties ◽

Radiative Forcing ◽

General Circulation ◽

Initial Conditions ◽

Model Simulation ◽

Circulation Model ◽

Interannual Variations ◽

Radiative Effects ◽

High Concentration ◽

Sea Temperature

Abstract The sensitivity of the interannual variations of the summer monsoons to imposed cloudiness has been studied with a general circulation model using the initial conditions prepared from the European Centre for Medium-Range Forecasts analyses of 1 May 1987 and 1988. The cloud optical properties in this global model are calculated from prognostically computed cloud liquid water. The model successfully simulates the contrasting behavior of these two successive monsoons. However, when the optical properties of the observed clouds are specified in the model runs, the simulations show some degradation over India and its vicinity. The main cause of this degradation is the reduced land–sea temperature contrast resulting from the radiative effects of the observed clouds imposed in such simulations. It is argued that the high concentration of condensed water content of clouds over the Indian land areas will serve to limit heating of the land, thereby reducing the thermal contrast that gives rise to a weak Somali jet. A countermonsoon circulation is, therefore, simulated in the vector difference field of 850-hPa winds from the model runs with externally specified clouds. This countermonsoon circulation is associated with an equatorial heat source that is the response of the model to the radiative effects of the imposed clouds. Indeed, there are at least two clear points that can be made: 1) the cloud–SST patterns, together, affect the interannual variability; and 2) with both clouds and SST imposed, the model simulation is less sensitive to initial conditions. Additionally, the study emphasizes the importance of dynamically consistent clouds developing in response to the dynamical, thermal, and moist state of the atmosphere during model integrations.

Download Full-text

Characterization of aerosol optical properties and model computed radiative forcing over a semi-arid region, Kadapa in India

Atmospheric Research ◽

10.1016/j.atmosres.2018.03.013 ◽

2018 ◽

Vol 209 ◽

pp. 36-49 ◽

Cited By ~ 7

Author(s):

C. Viswanatha Vachaspati ◽

G. Reshma Begam ◽

Y. Nazeer Ahammed ◽

K. Raghavendra Kumar ◽

R.R. Reddy

Keyword(s):

Optical Properties ◽

Arid Region ◽

Radiative Forcing ◽

Aerosol Optical Properties ◽

Semi Arid Region ◽

Semi Arid

Download Full-text

MACv2-SP: a parameterization of anthropogenic aerosol optical properties and an associated Twomey effect for use in CMIP6

Geoscientific Model Development ◽

10.5194/gmd-10-433-2017 ◽

2017 ◽

Vol 10 (1) ◽

pp. 433-452 ◽

Cited By ~ 57

Author(s):

Bjorn Stevens ◽

Stephanie Fiedler ◽

Stefan Kinne ◽

Karsten Peters ◽

Sebastian Rast ◽

...

Keyword(s):

Optical Properties ◽

Radiative Forcing ◽

Industrial Emissions ◽

Max Planck ◽

Aerosol Optical Properties ◽

Anthropogenic Aerosol ◽

Aerosol Radiative Forcing ◽

Clear Sky ◽

Aerosol Forcing ◽

Aerosol Radiative

Abstract. A simple plume implementation of the second version (v2) of the Max Planck Institute Aerosol Climatology, MACv2-SP, is described. MACv2-SP provides a prescription of anthropogenic aerosol optical properties and an associated Twomey effect. It was created to provide a harmonized description of post-1850 anthropogenic aerosol radiative forcing for climate modeling studies. MACv2-SP has been designed to be easy to implement, change and use, and thereby enable studies exploring the climatic effects of different patterns of aerosol radiative forcing, including a Twomey effect. MACv2-SP is formulated in terms of nine spatial plumes associated with different major anthropogenic source regions. The shape of the plumes is fit to the Max Planck Institute Aerosol Climatology, version 2, whose present-day (2005) distribution is anchored by surface-based observations. Two types of plumes are considered: one predominantly associated with biomass burning, the other with industrial emissions. These differ in the prescription of their annual cycle and in their optical properties, thereby implicitly accounting for different contributions of absorbing aerosol to the different plumes. A Twomey effect for each plume is prescribed as a change in the host model's background cloud-droplet population density using relationships derived from satellite data. Year-to-year variations in the amplitude of the plumes over the historical period (1850–2016) are derived by scaling the plumes with associated national emission sources of SO2 and NH3. Experiments using MACv2-SP are performed with the Max Planck Institute Earth System Model. The globally and annually averaged instantaneous and effective aerosol radiative forcings are estimated to be −0.6 and −0.5 W m−2, respectively. Forcing from aerosol–cloud interactions (the Twomey effect) offsets the reduction of clear-sky forcing by clouds, so that the net effect of clouds on the aerosol forcing is small; hence, the clear-sky forcing, which is more readily measurable, provides a good estimate of the total aerosol forcing.

Download Full-text