scholarly journals A new multispectral photometer for monitoring aerosol microphysical, optical, and radiative properties

2021 ◽  
Author(s):  
Yu Zheng ◽  
Huizheng Che ◽  
Yupeng Wang ◽  
Xiangao Xia ◽  
Xiuqing Hu ◽  
...  
Keyword(s):  
Water Vapor ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Integrated Design ◽  
Single Scattering ◽  
Radiative Properties ◽  
Mean Values ◽  
Smart Control ◽  
Fine Mode

Abstract. A new multispectral photometer, named CW193, was proposed in this study for monitoring aerosol microphysical, optical, and radiative properties. The instrument has a highly integrated design, smart control performance, and is composed of three parts (an optical head, a robotic drive platform, and a stents system). Because of its low maintenance requirements, this instrument is appropriate for the deployment in remote and unpopulated regions. Based on the synchronous measurements, the CW193 products was validated using reference data from the AERONET CE318 photometer. The results show that the raw digital counts from CW193 agree well the counts from AERONET (R2 > 0.97), with daily average triplets of around 1.2 % to 3.0 % for the ultraviolet band and less than 2.0 % for the visible and infrared bands. A good aerosol optical depth agreement (R > 0.99, 100 % within expected error) and root mean square error (RMSE) values ranging from 0.006 (for the 870 nm band) to 0.016 (for 440 nm the band) are obtained, with a relative mean bias (RMB) ranging from 0.922 to 1.112 and an aerosol optical depth bias within ±0.04. The maximum deviations for fine-mode particles varied from about 8.9 % to 77.6 %, whereas the variation for coarse-mode particles was about 13.1 % to 29.1 %. The deviation variations of the single scattering albedo were approximately 0.1–1.8 %, 0.6–1.9 %, 0.1–2.6 %, and 0.8–3.5 % for the 440 nm, 675 nm, 870 nm, and 1020 nm bands, respectively. For the aerosol direct radiative forcing, deviations of approximately 4.8–12.3 % was obtained at the Earth’s surface and 5.4–15.9 % for the top of the atmosphere. In addition, the water vapor retrievals showed a satisfactory accuracy, characterized by a high R value (~0.997), a small RMSE (~0.020), and good expected error distribution (100 % within expected error). The water vapor RMB was about 0.979 and the biases mostly varied within ±0.04, whereas the mean values were concentrated within ±0.02.

scholarly journals Sunphotometry of the 2006–2007 aerosol optical/radiative properties at the Himalayan Nepal Climate Observatory – Pyramid (5079 m a.s.l.)

2010 ◽  
Vol 10 (1) ◽  
pp. 1193-1220 ◽  
Author(s):  
G. P. Gobbi ◽  
F. Angelini ◽  
P. Bonasoni ◽  
G. P. Verza ◽  
A. Marinoni ◽  
...  
Keyword(s):  
High Altitude ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Monsoon Season ◽  
Good Reason ◽  
Single Scattering ◽  
Radiative Properties ◽  
Mountain Range ◽  
Monsoon Period

Abstract. In spite of being located at the heart of the highest mountain range in the world, the Himalayan Nepal Climate Observatory (5079 m a.s.l.) at the Ev-K2-CNR Pyramid is shown to be affected by the advection of pollution aerosols from the populated regions of southern Nepal and the Indo-Gangetic plains. Such an impact is observed along most of the period April 2006–March 2007 addressed here, with a minimum in the monsoon season. Backtrajectory-analysis indicates long-range transport episodes occurring in this period to originate mainly in the West Asian deserts. At this high altitude site, the measured aerosol optical depth is observed to be: 1) about one order of magnitude lower than the one measured at Gandhi College (60 m a.s.l.), in the Indo-Gangetic basin, and 2) maximum during the monsoon period, due to the presence of elevated (cirrus-like) particle layers. Assessment of the aerosol radiative forcing results to be hampered by the persistent presence of these high altitude particle layers, which impede a continuous measurement of both the aerosol optical depth and its radiative properties from sky radiance inversions. Even though the retrieved absorption coefficients of pollution aerosols was rather large (single scattering albedo of the order of 0.6–0.9 were observed in the month of April 2006), the corresponding low optical depths (~0.03 at 500 nm) are expected to limit the relevant radiative forcings. Still, the high specific forcing of this aerosol and its capability of altering snow surface albedo provide good reason for continuous monitoring.

scholarly journals Sunphotometry of the 2006–2007 aerosol optical/radiative properties at the Himalayan Nepal Climate Observatory-Pyramid (5079 m a.s.l.)

2010 ◽  
Vol 10 (22) ◽  
pp. 11209-11221 ◽  
Author(s):  
G. P. Gobbi ◽  
F. Angelini ◽  
P. Bonasoni ◽  
G. P. Verza ◽  
A. Marinoni ◽  
...  
Keyword(s):  
High Altitude ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Monsoon Season ◽  
Single Scattering ◽  
Radiative Properties ◽  
Mountain Range ◽  
Anthropogenic Aerosol ◽  
Aerosol Radiative

Abstract. In spite of being located at the heart of the highest mountain range in the world, the Himalayan Nepal Climate Observatory (5079 m a.s.l.) at the Ev-K2-CNR Pyramid is shown to be affected by the advection of pollution aerosols from the populated regions of southern Nepal and the Indo-Gangetic plains. Such an impact is observed along most of the period April 2006–March 2007 addressed here, with a minimum in the monsoon season. Backtrajectory-analysis indicates long-range transport episodes occurring in this year to originate mainly in the west Asian deserts. At this high altitude site, the measured aerosol optical depth is observed to be about one order of magnitude lower than the one measured at Ghandi College (60 m a.s.l.), in the Indo-Gangetic basin. As for Ghandi College, and in agreement with the in situ ground observations at the Pyramid, the fine mode aerosol optical depth maximizes during winter and minimizes in the monsoon season. Conversely, total optical depth maximizes during the monsoon due to the occurrence of elevated, coarse particle layers. Possible origins of these particles are wind erosion from the surrounding peaks and hydrated/cloud-processed aerosols. Assessment of the aerosol radiative forcing is then expected to be hampered by the presence of these high altitude particle layers, which impede an effective, continuous measurement of anthropogenic aerosol radiative properties from sky radiance inversions and/or ground measurements alone. Even though the retrieved absorption coefficients of pollution aerosols were rather large (single scattering albedo of the order of 0.6–0.9 were observed in the month of April 2006), the corresponding low optical depths (~0.03 at 500 nm) are expected to limit the relevant radiative forcing. Still, the high specific forcing of this aerosol and its capability of altering snow surface albedo provide good reasons for continuous monitoring.

Comprehensive Study of Optical, Physical, Chemical, and Radiative Properties of Total Columnar Atmospheric Aerosols over China: An Overview of Sun–Sky Radiometer Observation Network (SONET) Measurements

2018 ◽  
Vol 99 (4) ◽  
pp. 739-755 ◽  
Author(s):  
Z. Q. Li ◽  
H. Xu ◽  
K. T. Li ◽  
D. H. Li ◽  
Y. S. Xie ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Atmospheric Aerosol ◽  
Radiative Properties ◽  
Dust Particles ◽  
Aerosol Composition ◽  
Strong Light ◽  
Observation Network ◽  
Fine Mode ◽  
Cooling Effects

AbstractAn overview of Sun–Sky Radiometer Observation Network (SONET) measurements in China is presented. Based on observations at 16 distributed SONET sites in China, atmospheric aerosol parameters are acquired via standardization processes of operational measurement, maintenance, calibration, inversion, and quality control implemented since 2010. A climatology study is performed focusing on total columnar atmospheric aerosol characteristics, including optical (aerosol optical depth, ÅngstrÖm exponent, fine-mode fraction, single-scattering albedo), physical (volume particle size distribution), chemical composition (black carbon; brown carbon; fine-mode scattering component, coarse-mode component; and aerosol water), and radiative properties (aerosol radiative forcing and efficiency). Data analyses show that aerosol optical depth is low in the west but high in the east of China. Aerosol composition also shows significant spatial and temporal variations, leading to noticeable diversities in optical and physical property patterns. In west and north China, aerosols are generally affected by dust particles, while monsoon climate and human activities impose remarkable influences on aerosols in east and south China. Aerosols in China exhibit strong light-scattering capability and result in significant radiative cooling effects.

scholarly journals Modelling of nitrate and ammonium-containing aerosols in presence of sea salt

2006 ◽  
Vol 6 (12) ◽  
pp. 4809-4821 ◽  
Author(s):  
G. Myhre ◽  
A. Grini ◽  
S. Metzger
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Transport Model ◽  
Meteorological Condition ◽  
Global Scale ◽  
Sea Salt ◽  
Aerosol Composition ◽  
Fine Mode ◽  
High Concentrations

Abstract. A thermodynamical model for treatment of gas/aerosol partitioning of semi volatile inorganic aerosols has been implemented in a global chemistry and aerosol transport model (Oslo CTM2). The sulphur cycle and sea salt particles have been implemented earlier in the Oslo CTM2 and the focus of this study is on nitrate partitioning to the aerosol phase and if particulate nitrate is expected to form in fine or coarse mode aerosols. Modelling of the formation of fine mode nitrate particles is complicated since it depends on other aerosol components and aerosol precursors as well as meteorological condition. The surface concentrations from the model are compared to observed surface concentrations at around 20 sites around Europe for nitrate and ammonium. The agreement for nitrate is good but the modelled values are somewhat underestimated compared to observations at high concentrations, whereas for ammonium the agreement is very good. However, we underscore that such a comparison is not of large importance for the aerosol optical depth of particulate nitrate since the vertical profile of aerosol components and their precursors are so important. Fine mode nitrate formation depends on vertical profiles of both ammonia/ammonium and sulphate. The model results show that fine mode particulate nitrate play a non-negligible role in the total aerosol composition in certain industrialized regions and therefore have a significant local radiative forcing. On a global scale the aerosol optical depth of fine mode nitrate is relatively small due to limited availability of ammonia and loss to larger sea salt particles. Inclusion of sea salt in the calculations reduces the aerosol optical depth and burden of fine mode nitrate by 25% on a global scale but with large regional variations.

scholarly journals Impact of Post-Harvest Biomass Burning on Aerosol Characteristics and Radiative Forcing over Patiala, North-West region of India

1970 ◽  
Vol 8 (3) ◽  
pp. 11-24 ◽  
Author(s):  
Deepti Sharma ◽  
Manjit Singh ◽  
Darshan Singh
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Biomass Burning ◽  
Satellite Data ◽  
Radiative Forcing ◽  
Mass Concentration ◽  
Mean Values ◽  
North West ◽  
Post Harvest ◽  
West Region

The present study deals with impact of post-harvest biomass burning on aerosol characteristics over Patiala (Lat: 30.33°N; Long: 76.4°E), Punjab state, India during 2008-09, using ground based and satellite data. Results of Aerosol Optical Depth (AOD) measurements using MICROTOPS II show significant variations with highest AOD500 ≈2.65 in October 2008 and ≈1.71 in November 2009. The maximum monthly mean values of angstrom parameters “α” and “β” are 1.13±0.16 and 0.39±0.20, respectively. Daily averaged values of Black Carbon (BC) mass concentration during day time show significant variations (8-18μg/m³) yielding SSA varying from 0.76-0.88 during highly turbid days and 0.95-0.97 during less turbid days. During highly turbid days, the estimated atmospheric radiative forcing using SBDART varies from +43.0 to +86.5Wm-2 suggesting high BC concentration in the atmosphere associated with paddy residue burning in the fields. DOI: http://dx.doi.org/10.3126/jie.v8i3.5927 JIE 2011; 8(3): 11-24

scholarly journals Smoke aerosol and its radiative effects during extreme fire event over Central Russia in summer 2010

2011 ◽  
Vol 4 (5) ◽  
pp. 6351-6386 ◽  
Author(s):  
N. Chubarova ◽  
Y. Nezval' ◽  
M. Sviridenkov ◽  
A. Smirnov ◽  
I. Slutsker
Keyword(s):  
Radiative Forcing ◽  
Visible Region ◽  
Single Scattering ◽  
Radiative Properties ◽  
Aerosol Size Distribution ◽  
Absolute Maximum ◽  
Fire Event ◽  
Central Russia ◽  
Uv Irradiance ◽  
Fine Mode

Abstract. Different microphysical, optical and radiative properties of aerosol were analyzed during the severe fires in summer 2010 over Central Russia using ground measurements at two AERONET sites in Moscow and Zvenigorod (Moscow suburb) and radiative measurements in Moscow. Volume aerosol size distribution in smoke conditions was shown to have a bimodal character with the significant prevalence of fine mode aerosol particles which effective radius shifted to higher values (reff-fine = 0.24 μm against approximately 0.15 μm in typical conditions). Imaginary part of refractive index in visible region was characterized by lower values compared with typical conditions (REFI = 0.006 against REFI = 0.01) and single scattering albedo (SSA) was significantly higher (SSAλ=675nm = 0.95 against SSAλ=675nm ~ 0.9). Extremely high daily average AOT's were observed on 6–8 August reaching the absolute maximum on 7 August up to AOT500 = 6.4 in Moscow and AOT500 = 5.9 at Zvenigorod. A dramatic attenuation of solar irradiance at ground in cloudless but smoky conditions was also observed. Maximum irradiance loss has reached 64% for global shortwave irradiance, 91% for UV radiation 300–380 nm and 97% for erythemally-weighted UV irradiance even at relatively high solar elevation due to extremely high AOT and smaller SSA values in UV (0.8–0.9) compared with SSA in visible region of spectrum. The assessments of radiative forcing effect (RFE) at the TOA indicated a significant cooling of the smoky atmosphere. Instant RFE reached −167 Wm−2 at AOT500 = 6.4 while climatological RFE calculated for monthly mean AOT in August 2010 was about −65 Wm−2 compared with −20 Wm−2 for typical aerosol conditions according to the 10 year period of measurements in Moscow.

scholarly journals Aerosol Single Scattering Albedo retrieval in the UV range: an application to OMI satellite validation

2010 ◽  
Vol 10 (2) ◽  
pp. 331-340 ◽  
Author(s):  
I. Ialongo ◽  
V. Buchard ◽  
C. Brogniez ◽  
G. R. Casale ◽  
A. M. Siani
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Spectral Irradiance ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Ozone Monitoring Instrument ◽  
Mean Values ◽  
Absorbing Aerosols

Abstract. The aerosol Single Scattering Albedo (SSA) and Absorbing Aerosol Optical Depth (AAOD) at 320.1 nm are derived at Rome site by the comparison between Brewer and modelled spectra. The UVSPEC radiative transfer model is used to calculate the UV irradiances for different SSA values, taking into account as input data total ozone and Aerosol Optical Depth (AOD) obtained from Brewer spectral measurements. The accuracy in determining SSA depends on the aerosol amount and on Solar Zenith Angle (SZA) value: SSA uncertainty increases when AOD and SZA decrease. The monthly mean values of SSA and AAOD during the period January 2005–June 2008 are analysed, showing a monthly and seasonal variability. It is found that the SSA and AAOD averages are 0.80±0.08 and 0.056±0.028, respectively. AAOD retrievals are also used to quantify the error in the Ozone Monitoring Instrument (OMI) surface UV products due to absorbing aerosols, not included in the current OMI UV algorithm. OMI and Brewer UV irradiances at 324.1 nm and Erythemal Dose Rates (EDRs) under clear sky conditions, are compared as a function of AAOD. Three methods are considered to investigate on the applicability of an absorbing aerosol correction on OMI UV data at Rome site. Depending on the correction methodology, the bias value decreases from 18% to 2% for spectral irradiance at 324.1 nm and from 25% to 8% for EDR.

scholarly journals Dust optical properties over North Africa and Arabian Peninsula derived from the AERONET dataset

2011 ◽  
Vol 11 (7) ◽  
pp. 20181-20201 ◽  
Author(s):  
D. Kim ◽  
M. Chin ◽  
H. Yu ◽  
T. F. Eck ◽  
A. Sinyuk ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
North Africa ◽  
Radiative Forcing ◽  
Arabian Peninsula ◽  
Single Scattering ◽  
Major Fraction ◽  
Remote Sensing Techniques

Abstract. Dust optical properties over North Africa and the Arabian Peninsula are extracted from the quality assured multi-year datasets obtained at 14 sites of the Aerosol Robotic Network (AERONET). We select the data with (a) large aerosol optical depth (AOD ≥ 0.4 at 440 nm) and (b) small Ångström exponent (Åext ≤ 0.2) for retaining high accuracy and reducing interference of non-dust aerosols. The result indicates that the major fraction of high aerosol optical depth days are dominated by dust over these sites even though it varies depending on location and time. We have found that the annual mean and standard deviation of single scattering albedo, asymmetry parameter, real refractive index, and imaginary refractive index for Saharan and Arabian desert dust is 0.946 ± 0.005, 0.752 ± 0.014, 1.498 ± 0.032, and 0.0025 ± 0.0036 at 550 nm wavelength, respectively. Dust aerosol selected by this method is less absorbing than the previously reported values over these sites. The weaker absorption of dust from this study is consistent with the previously studies using remote sensing techniques. These results can help to constrain uncertainties in estimating global dust shortwave radiative forcing.

scholarly journals Dust optical properties over North Africa and Arabian Peninsula derived from the AERONET dataset

2011 ◽  
Vol 11 (20) ◽  
pp. 10733-10741 ◽  
Author(s):  
D. Kim ◽  
M. Chin ◽  
H. Yu ◽  
T. F. Eck ◽  
A. Sinyuk ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
North Africa ◽  
Radiative Forcing ◽  
Arabian Peninsula ◽  
Single Scattering ◽  
Major Fraction ◽  
Remote Sensing Techniques

Abstract. Dust optical properties over North Africa and the Arabian Peninsula are extracted from the quality assured multi-year datasets obtained at 14 sites of the Aerosol Robotic Network (AERONET). We select the data with (a) large aerosol optical depth (AOD ≥ 0.4 at 440 nm) and (b) small Ångström exponent (Åext ≤ 0.2) for retaining high accuracy and reducing interference of non-dust aerosols. The result indicates that the major fraction of high aerosol optical depth days are dominated by dust over these sites even though it varies depending on location and time. We have found that the annual mean and standard deviation of single scattering albedo, asymmetry parameter, real refractive index, and imaginary refractive index for Saharan and Arabian desert dust is 0.944 ± 0.005, 0.752 ± 0.014, 1.498 ± 0.032, and 0.0024 ± 0.0034 at 550 nm wavelength, respectively. Dust aerosol selected by this method is less absorbing than the previously reported values over these sites. The weaker absorption of dust from this study is consistent with the studies using remote sensing techniques from satellite. These results can help to constrain uncertainties in estimating global dust shortwave radiative forcing.

scholarly journals Optical and Radiative Properties of Aerosols over Two Locations in the North-West Part of India during Premonsoon Season

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Yogesh Kant ◽  
Atinderpal Singh ◽  
Debashis Mitra ◽  
Darshan Singh ◽  
P. Srikanth ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Anthropogenic Activities ◽  
Single Scattering ◽  
Radiative Properties ◽  
Average Mass ◽  
North West ◽  
Aerosol Radiative Forcing ◽  
The North ◽  
Fine Mode ◽  
Boundary Layer Dynamics

The present study examines the aerosol characteristics over two locations in the northwest region of India (Dehradun and Patiala) during premonsoon season of 2013. The average mass concentrations of particulates (PM10; PM2.5; PM1) were found to be118±36,34±11, and19±10 µgm−3and140±48,30±13, and14±06 µgm−3over Dehradun and Patiala, respectively. The average aerosol optical depth (AOD500 nm) is observed to be0.62±0.11over Dehradun and0.56±0.21over Patiala. Ångström exponent and fine mode fraction show higher values over Dehradun as compared to Patiala. The average mass concentration of black carbon was found to be3343±546 ngm−3and6335±760 ngm−3over Dehradun and Patiala, respectively. The diurnal pattern of BC is mainly controlled by boundary layer dynamics and local anthropogenic activities over both the stations. The average single scattering albedo (SSA500 nm) exhibited low value over Patiala (0.83±0.01) in comparison to Dehradun (0.90±0.01), suggesting the abundance of absorbing type aerosols over Patiala. The average atmospheric aerosol radiative forcing is +37.34 Wm−2and +54.81 Wm−2over Dehradun and Patiala, respectively, leading to atmospheric heating rate of 1.0 K day−1over Dehradun and 1.5 K day−1over Patiala.

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