scholarly journals Link between local scale BC emissions and large scale atmospheric solar absorption

2011 ◽  
Vol 11 (7) ◽  
pp. 21319-21361 ◽  
Author(s):  
P. S. Praveen ◽  
T. Ahmed ◽  
A. Kar ◽  
I. H. Rehman ◽  
V. Ramanathan
Keyword(s):  
Optical Properties ◽  
Radiative Forcing ◽  
Large Scale ◽  
Positive Impact ◽  
Monsoon Season ◽  
Regional Climate ◽  
Regional Scale ◽  
Local Scale ◽  
Dry Season ◽  
Aerosol Optical Properties

Abstract. Project Surya has documented indoor and outdoor concentrations of black carbon (BC) from traditional biomass burning cook stoves in a rural village located in the Indo-Gangetic Plains (IGP) region of N. India from November 2009- September 2010. In this paper, we systematically document the link between local scale aerosol properties and column averaged regional aerosol optical properties and atmospheric radiative forcing. We report observations from the first phase of Project Surya to estimate the source dependent (biomass and fossil fuels) aerosol optical properties from local to regional scale. Data were collected using surface based observations of BC, organic carbon (OC), aerosol light absorption, scattering coefficient at the Surya village (SVI_1) located in IGP region, and satellite and AERONET observations at the regional scale (IGP). The daily mean BC concentrations at SVI_1 showed the large increase of BC during the dry season (December to February) with values reaching 35 μg m−3. Space based LIDAR data reveal how the biomass smoke is trapped within the first kilometre during the dry season and its extension to above 5 km during the pre-monsoon season. As a result during the dry season, the variance in the daily mean SSA and column aerosol optical properties at the local IGP site correlated (with slopes in the range of 0.85 to 1.06 and R2>0.4) well with the "IGP_AERONET" (mean of six AERONET sites), thus suggesting in-situ observations at few locations can be used to infer spatial mean forcing. The atmospheric forcing due to BC and OC exceeded 20 W m−2 during all months from November to May, leading to the deduction that elimination of cook stove smoke emissions through clean cooking technologies will likely have a major positive impact on health and the regional climate.

scholarly journals Link between local scale BC emissions in the Indo-Gangetic Plains and large scale atmospheric solar absorption

2012 ◽  
Vol 12 (2) ◽  
pp. 1173-1187 ◽  
Author(s):  
P. S. Praveen ◽  
T. Ahmed ◽  
A. Kar ◽  
I. H. Rehman ◽  
V. Ramanathan
Keyword(s):  
Optical Properties ◽  
Radiative Forcing ◽  
Large Scale ◽  
Positive Impact ◽  
Monsoon Season ◽  
Regional Scale ◽  
Local Scale ◽  
Dry Season ◽  
Aerosol Optical Properties ◽  
Gangetic Plains

Abstract. Project Surya has documented indoor and outdoor concentrations of black carbon (BC) from traditional biomass burning cook stoves in a rural village located in the Indo-Gangetic Plains (IGP) region of N. India from November 2009–September 2010. In this paper, we systematically document the link between local scale aerosol properties and column averaged regional aerosol optical properties and atmospheric radiative forcing. We document observations from the first phase of Project Surya and estimate the source dependent (biomass and fossil fuels) aerosol optical properties from local to regional scale. Data were collected using surface based observations of BC, organic carbon (OC), aerosol light absorption, scattering coefficient at the Surya village (SVI_1) located in IGP region and integrated with satellite and AERONET observations at the regional scale (IGP). The daily mean BC concentrations at SVI_1 showed a large increase of BC during the dry season (December to February) with values reaching 35 μg m−3. Space based LIDAR data revealed how the biomass smoke was trapped within the first kilometer during the dry season and extended to above 5 km during the pre-monsoon season. As a result, during the dry season, the variance in the daily mean single scattering albedo (SSA), the ratio of scattering to extinction coefficient, and column aerosol optical properties at the local IGP site correlated (with slopes in the range of 0.85 to 1.06 and R2>0.4) well with the "IGP_AERONET" (mean of six AERONET sites). The statistically significant correlation suggested that in-situ observations can be used to derive spatial mean forcing, at least for the dry season. The atmospheric forcing due to BC and OC exceeded 20 Wm−2 during all months from November to May, supporting the deduction that elimination of cook stove smoke emissions through clean cooking technologies will likely have a major positive impact not only on human health but also on regional climate.

scholarly journals Aerosol optical properties and radiative forcing in the high Himalaya based on measurements at the Nepal Climate Observatory – pyramid site (5100 m a.s.l)

2010 ◽  
Vol 10 (2) ◽  
pp. 5627-5663 ◽  
Author(s):  
S. Marcq ◽  
P. Laj ◽  
J. C. Roger ◽  
P. Villani ◽  
K. Sellegri ◽  
...  
Keyword(s):  
Optical Properties ◽  
Radiative Forcing ◽  
Large Scale ◽  
Aerosol Particles ◽  
Small Scale ◽  
Atmospheric Layer ◽  
Aerosol Optical Properties ◽  
Diurnal Variability ◽  
Regional Pollution ◽  
Pollution Events

Abstract. Intense anthropogenic emissions over the Indian sub-continent lead to the formation of layers of particulate pollution that can be transported to the high altitude regions of the Himalaya-Hindu-Kush (HKH). Aerosol particles contain a substantial fraction of strongly absorbing material, including black carbon (BC), organic compounds (OC), and dust all of which can contribute to atmospheric warming, in addition to greenhouse gases. Using a 3-year record of continuous measurements of aerosol optical properties, we present a time series of key climate relevant aerosol properties including the aerosol absorption (σap) and scattering (σsp) coefficients as well as the single-scattering albedo (w). Results of this investigation show substantial seasonal variability of these properties, with long range transport during the pre- and post-monsoon seasons and efficient precipitation scavenging of aerosol particles during the monsoon season. The monthly averaged scattering coefficients range from 0.1 Mm−1 (monsoon) to 20 Mm−1 while the average absorption coefficients range from 0.5 Mm−1 to 3.5 Mm−1. Both have their maximum values during the pre-monsoon period (April) and reach a minimum during Monsoon (July–August). This leads to w values from 0.86 (pre-monsoon) to 0.79 (monsoon) seasons. Significant diurnal variability due to valley wind circulation is also reported. Using typical air mass trajectories encountered at the station, and aerosol optical depth (aod) measurements, we calculated the resulting direct local radiative forcing due to aerosols. We found that the presence of absorbing particulate material can locally induce an additional top of the atmosphere (TOA) forcing of 10 to 20 W m−2 for the first atmospheric layer (500 m above surface). The TOA positive forcing depends on the presence of snow at the surface, and takes place preferentially during episodes of regional pollution occurring on a very regular basis in the Himalayan valleys. Warming of the first atmospheric layer is paralleled by a substantial decrease of the amount of radiation reaching the surface. The surface forcing is estimated to range from −4 to −20 W m−2 for small-scale regional pollution events and large-scale pollution events, respectively. The calculated surface forcing is also very dependent on surface albedo, with maximum values occurring over a snow-covered surface. Overall, this work presents the first estimates of aerosol direct radiative forcing over the high Himalaya based on in-situ aerosol measurements, and results suggest a TOA forcing significantly greater than the IPCC reported values for green house gases.

scholarly journals The direct effect of aerosols on solar radiation based on satellite observations, reanalysis datasets, and spectral aerosol optical properties from Global Aerosol Data Set (GADS)

2007 ◽  
Vol 7 (1) ◽  
pp. 753-783 ◽  
Author(s):  
N. Hatzianastassiou ◽  
C. Matsoukas ◽  
E. Drakakis ◽  
P. W. Stackhouse ◽  
P. Koepke ◽  
...  
Keyword(s):  
Optical Properties ◽  
Solar Radiation ◽  
Hydrological Cycle ◽  
Regional Scale ◽  
Local Scale ◽  
Transfer Model ◽  
Surface Cooling ◽  
Anthropogenic Aerosols ◽  
Aerosol Optical Properties ◽  
Data Set

Abstract. A global estimate of the seasonal direct radiative effect (DRE) of natural plus anthropogenic aerosols on solar radiation under all-sky conditions is obtained by combining satellite measurements and reanalysis data with a spectral radiative transfer model. The estimates are obtained with detailed spectral model computations separating the ultraviolet (UV), visible and near-infrared wavelengths. The global distribution of spectral aerosol optical properties was taken from the Global Aerosol Data Set (GADS) whereas data for clouds, water vapour, ozone, carbon dioxide, methane and surface albedo were taken from various satellite and reanalysis datasets. Using these aerosol properties and other related variables, we generate climatological (for the 12-year period 1984–1995) monthly mean aerosol DREs. The global annual mean DRE on the outgoing SW radiation at the top of atmosphere (TOA, ΔFTOA) is 1.62 Wm−2 (with a range of –10 to 15 Wm−2, positive values corresponding to planetary cooling), the effect on the atmospheric absorption of SW radiation (ΔFatmab) is 1.6 Wm−2 (values up to 35 Wm−2, corresponding to atmospheric warming), and the effect on the surface downward and absorbed SW radiation (Δ Fsurf, and ΔFsurfnet, respectively) is –3.93 and –3.22 Wm−2 (values up to –45 and –35 Wm−2, respectively, corresponding to surface cooling.) According to our results, aerosols decrease/increase the planetary albedo by –3 to 13% at the local scale, whereas on planetary scale the result is an increase of 1.5%. Aerosols can warm locally the atmosphere by up to 0.98 K day−1, whereas they can cool the Earth's surface by up to –2.9 K day−1. Both these effects, which can significantly modify atmospheric dynamics and the hydrological cycle, can produce significant planetary cooling on a regional scale, although planetary warming can arise over highly reflecting surfaces. The aerosol DRE at the Earth's surface compared to TOA can be up to 15 times larger at the local scale. The largest aerosol DRE takes place in the northern hemisphere both at the surface and the atmosphere, arising mainly at ultraviolet and visible wavelengths.

scholarly journals Aerosol optical properties of size segregated aerosol particles and radiative forcing over Pokhara valley

2019 ◽  
Vol 8 ◽  
pp. 1-10
Author(s):  
Jeevn Regmi ◽  
Khem N Poudyal ◽  
Amod Pokhrel ◽  
Anthony Barinelli ◽  
Rudra Aryal
Keyword(s):  
Optical Properties ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Monsoon Season ◽  
Aerosol Particles ◽  
Aerosol Optical Properties ◽  
Maximum Value ◽  
Fine Mode ◽  
Pokhara Valley

The AERONET  data from sun/sky radiometer over  Pokhara (2017) was analyzed to observe aerosol optical depth (AOD) of size segregated particles and radiative forcing. Fine mode particles have over seventy percent of contribution to AOD in all months with the maximum, ninety-four percent, on November and February, and minimum on July, seventy-nine percent. The monthly mean top of atmosphere (TOA) forcing are negative −23.225 ± 4.71 Wm−2 in March, −28.958 ± 4.71 Wm−2 in April and −19.616 ± 4.71 Wm−2 in May. The negative value of TOA during all the months in pre-monsoon season indicates net cooling. Whereas surface forcing (BOA forcing) was found to be positive with a maximum value of 111.18 ± 27.63 Wm−2 during April and a minimum of 56.22 ± 27.63 Wm−2 during May. The resultant atmospheric forcing is the absorption due to aerosols within the atmosphere and found to be +267.57 Wm−2 during April and +228.55 Wm−2 during May; indicating significant heating of the atmosphere.

scholarly journals Aerosol optical properties and radiative forcing in the high Himalaya based on measurements at the Nepal Climate Observatory-Pyramid site (5079 m a.s.l.)

2010 ◽  
Vol 10 (13) ◽  
pp. 5859-5872 ◽  
Author(s):  
S. Marcq ◽  
P. Laj ◽  
J. C. Roger ◽  
P. Villani ◽  
K. Sellegri ◽  
...  
Keyword(s):  
Optical Properties ◽  
Radiative Forcing ◽  
Large Scale ◽  
Aerosol Particles ◽  
Small Scale ◽  
Atmospheric Layer ◽  
Aerosol Optical Properties ◽  
Diurnal Variability ◽  
Regional Pollution ◽  
Pollution Events

Abstract. Intense anthropogenic emissions over the Indian sub-continent lead to the formation of layers of particulate pollution that can be transported to the high altitude regions of the Himalaya-Hindu-Kush (HKH). Aerosol particles contain a substantial fraction of strongly absorbing material, including black carbon (BC), organic compounds (OC), and dust all of which can contribute to atmospheric warming, in addition to greenhouse gases. Using a 3-year record of continuous measurements of aerosol optical properties, we present a time series of key climate relevant aerosol properties including the aerosol absorption (σap) and scattering (σsp) coefficients as well as the single-scattering albedo (w0). Results of this investigation show substantial seasonal variability of these properties, with long range transport during the pre- and post-monsoon seasons and efficient precipitation scavenging of aerosol particles during the monsoon season. The monthly averaged scattering coefficients range from 0.1 Mm−1 (monsoon) to 20 Mm−1 while the average absorption coefficients range from 0.5 Mm−1 to 3.5 Mm−1. Both have their maximum values during the pre-monsoon period (April) and reach a minimum during Monsoon (July–August). This leads to dry w0 values from 0.86 (pre-monsoon) to 0.79 (monsoon) seasons. Significant diurnal variability due to valley wind circulation is also reported. Using aerosol optical depth (AOD) measurements, we calculated the resulting direct local radiative forcing due to aerosols for selected air mass cases. We found that the presence of absorbing particulate material can locally induce an additional top of the atmosphere (TOA) forcing of 10 to 20 W m−2 for the first atmospheric layer (500 m above surface). The TOA positive forcing depends on the presence of snow at the surface, and takes place preferentially during episodes of regional pollution occurring on a very regular basis in the Himalayan valleys. Warming of the first atmospheric layer is paralleled by a substantial decrease of the amount of radiation reaching the surface. The surface forcing is estimated to range from −4 to −20 W m−2 for small-scale regional pollution events and large-scale pollution events, respectively. The calculated surface forcing is also very dependent on surface albedo, with maximum values occurring over a snow-covered surface. Overall, this work presents the first estimates of aerosol direct radiative forcing over the high Himalaya based on in-situ aerosol measurements, and results suggest a TOA forcing significantly greater than the IPCC reported values for green house gases.

scholarly journals The direct effect of aerosols on solar radiation based on satellite observations, reanalysis datasets, and spectral aerosol optical properties from Global Aerosol Data Set (GADS)

2007 ◽  
Vol 7 (10) ◽  
pp. 2585-2599 ◽  
Author(s):  
N. Hatzianastassiou ◽  
C. Matsoukas ◽  
E. Drakakis ◽  
P. W. Stackhouse ◽  
P. Koepke ◽  
...  
Keyword(s):  
Optical Properties ◽  
Solar Radiation ◽  
Hydrological Cycle ◽  
Regional Scale ◽  
Local Scale ◽  
Transfer Model ◽  
Surface Cooling ◽  
Anthropogenic Aerosols ◽  
Aerosol Optical Properties ◽  
Data Set

Abstract. A global estimate of the seasonal direct radiative effect (DRE) of natural plus anthropogenic aerosols on solar radiation under all-sky conditions is obtained by combining satellite measurements and reanalysis data with a spectral radiative transfer model and spectral aerosol optical properties taken from the Global Aerosol Data Set (GADS). The estimates are obtained with detailed spectral model computations separating the ultraviolet (UV), visible and near-infrared wavelengths. The global distribution of spectral aerosol optical properties was taken from GADS whereas data for clouds, water vapour, ozone, carbon dioxide, methane and surface albedo were taken from various satellite and reanalysis datasets. Using these aerosol properties and other related variables, we generate climatological (for the 12-year period 1984–1995) monthly mean aerosol DREs. The global annual mean DRE on the outgoing SW radiation at the top of atmosphere (TOA, ΔFTOA) is −1.62 W m−2 (with a range of −15 to 10 W m−2, negative values corresponding to planetary cooling), the effect on the atmospheric absorption of SW radiation (ΔFatmab) is 1.6 W m−2 (values up to 35 W m−2, corresponding to atmospheric warming), and the effect on the surface downward and absorbed SW radiation (ΔFsurf, and ΔFsurfnet, respectively) is −3.93 and −3.22 W m−2 (values up to −45 and −35 W m−2, respectively, corresponding to surface cooling). According to our results, aerosols decrease/increase the planetary albedo by −3 to 13% at the local scale, whereas on planetary scale the result is an increase of 1.5%. Aerosols can warm locally the atmosphere by up to 0.98 K day−1, whereas they can cool the Earth's surface by up to −2.9 K day−1. Both these effects, which can significantly modify atmospheric dynamics and the hydrological cycle, can produce significant planetary cooling on a regional scale, although planetary warming can arise over highly reflecting surfaces. The aerosol DRE at the Earth's surface compared to TOA can be up to 15 times larger at the local scale. The largest aerosol DRE takes place in the northern hemisphere both at the surface and the atmosphere, arising mainly at ultraviolet and visible wavelengths.

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

2014 ◽  
Vol 7 (5) ◽  
pp. 2503-2516 ◽  
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.

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

2016 ◽  
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.

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

2019 ◽  
Vol 19 (14) ◽  
pp. 9181-9208 ◽  
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.

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