scholarly journals A global climatology of stratospheric aerosol surface area density deduced from Stratospheric Aerosol and Gas Experiment II measurements: 1984-1994

1997 ◽  
Vol 102 (D7) ◽  
pp. 8967-8976 ◽  
Author(s):  
L. W. Thomason ◽  
L. R. Poole ◽  
T. Deshler
Keyword(s):  
Surface Area ◽  
Stratospheric Aerosol ◽  
Area Density

scholarly journals SAGE II measurements of stratospheric aerosol properties at non-volcanic levels

2008 ◽  
Vol 8 (4) ◽  
pp. 983-995 ◽  
Author(s):  
L. W. Thomason ◽  
S. P. Burton ◽  
B.-P. Luo ◽  
T. Peter
Keyword(s):  
Surface Area ◽  
Historical Record ◽  
Stratospheric Aerosol ◽  
The Other ◽  
Processing Algorithm ◽  
Aerosol Extinction ◽  
Retrieval Process ◽  
Satellite Measurements ◽  
Area Density ◽  
Aerosol Properties

Abstract. Since 2000, stratospheric aerosol levels have been relatively stable and at the lowest levels observed in the historical record. Given the challenges of making satellite measurements of aerosol properties at these levels, we have performed a study of the sensitivity of the product to the major components of the processing algorithm used in the production of SAGE II aerosol extinction measurements and the retrieval process that produces the operational surface area density (SAD) product. We find that the aerosol extinction measurements, particularly at 1020 nm, remain robust and reliable at the observed aerosol levels. On the other hand, during background periods, the SAD operational product has an uncertainty of at least a factor of 2 due to the lack of sensitivity to particles with radii less than 100 nm.

scholarly journals SAGE II measurements of stratospheric aerosol properties at non-volcanic levels

2007 ◽  
Vol 7 (3) ◽  
pp. 6959-6997 ◽  
Author(s):  
L. W. Thomason ◽  
S. P. Burton ◽  
B.-P. Luo ◽  
T. Peter
Keyword(s):  
Surface Area ◽  
Historical Record ◽  
Stratospheric Aerosol ◽  
The Other ◽  
Processing Algorithm ◽  
Aerosol Extinction ◽  
Retrieval Process ◽  
Satellite Measurements ◽  
Area Density ◽  
Aerosol Properties

Abstract. Since 2000, stratospheric aerosol levels have been relatively stable and at the lowest levels observed in the historical record. Given the challenges of making satellite measurements of aerosol properties at these levels, we have performed a study of the sensitivity of the product to the major components of the processing algorithm used in the production of SAGE II aerosol extinction measurements and the retrieval process that produces the operational surface area density (SAD) product. We find that the aerosol extinction measurements, particularly at 1020 nm, remain robust and reliable at the observed aerosol levels. On the other hand, background periods, the SAD operational product has an uncertainty of at least a factor of 2 due to the lack of sensitivity to particles with radii less than 100 nm.

A 2010 Mapping of the Constructed Surface Area Density for S.E. Asia - Preliminary Results

2010 ◽  
Vol 30 (0) ◽  
pp. 181 ◽  
Author(s):  
Paul C. Sutton ◽  
Christopher D. Elvidge ◽  
Benjamin T. Tuttle ◽  
Daniel Ziskin ◽  
Kimberly Baugh ◽  
...  
Keyword(s):  
Surface Area ◽  
Area Density ◽  
Preliminary Results

Unbiased stereological estimation of the surface area of gradient surface processes

1998 ◽  
Vol 30 (4) ◽  
pp. 904-920 ◽  
Author(s):  
Ute Hahn ◽  
Dietrich Stoyan
Keyword(s):  
Surface Area ◽  
Surface Processes ◽  
Finite Variance ◽  
Area Density ◽  
Gradient Surface

An unbiased stereological estimator for surface area density is derived for gradient surface processes which form a particular class of non-stationary spatial surface processes. Vertical planar sections are used for the estimation. The variance of the estimator is studied and found to be infinite for certain types of surface processes. A modification of the estimator is presented which exhibits finite variance.

scholarly journals Description and evaluation of tropospheric chemistry and aerosols in the Community Earth System Model (CESM1.2)

2014 ◽  
Vol 7 (6) ◽  
pp. 8875-8940 ◽  
Author(s):  
S. Tilmes ◽  
J.-F. Lamarque ◽  
L. K. Emmons ◽  
D. E. Kinnison ◽  
P.-L. Ma ◽  
...  
Keyword(s):  
Surface Area ◽  
Atmospheric Chemistry ◽  
Earth System Model ◽  
Tropospheric Chemistry ◽  
System Model ◽  
Earth System ◽  
Chemical Production ◽  
Area Density ◽  
Community Earth System Model ◽  
The Difference

Abstract. The Community Atmosphere Model (CAM), version 5, is now coupled to extensive tropospheric and stratospheric chemistry, called CAM5-chem, and is available in addition to CAM4-chem in the Community Earth System Model (CESM) version 1.2. Both configurations are well suited as tools for atmospheric-chemistry modeling studies in the troposphere and lower stratosphere, whether with internally derived "free running" (FR) meteorology, or "specified dynamics" (SD). The main focus of this paper is to compare the performance of these configurations against observations from surface, aircraft, and satellite, as well as understand the origin of the identified differences. We particularly focus on comparing present-day methane lifetime estimates within the different model configurations, which range between 7.8 years in the SD configuration of CAM5-chem and 8.8 years in the FR configuration of CAM4-chem. We find that tropospheric surface area density is an important factor in controlling the burden of the hydroxyl radical (OH), which causes differences in tropical methane lifetime of about half a year between CAM4-chem and CAM5-chem. In addition, different distributions of nitrogen oxides (NOx) produced from lightning production explain about half of the difference between SD and FR model versions in both CAM4-chem and CAM5-chem. Remaining differences in the tropical OH burden are due to enhanced tropical ozone burden in SD configurations compared to the FR versions, which are not only caused by differences in chemical production or loss, but also by transport and mixing. For future studies, we recommend the use of CAM5-chem, due to improved aerosol description and inclusion of aerosol-cloud interactions. However, smaller tropospheric surface area density in the current version of CAM5-chem compared to CAM4-chem results in larger oxidizing capacity in the troposphere and therefore a shorter methane lifetime.

scholarly journals The Lifshitz–Slyozov–Wagner equation for reaction-controlled kinetics

2010 ◽  
Vol 140 (2) ◽  
pp. 273-289 ◽  
Author(s):  
Apostolos Damialis
Keyword(s):  
Surface Area ◽  
Mean Field ◽  
Weak Form ◽  
Spherical Particles ◽  
Type Problem ◽  
Area Density ◽  
Wagner Equation

We rigorously derive a weak form of the Lifshitz–Slyozov–Wagner equation as the homogenization limit of a Stefan-type problem describing reaction-controlled coarsening of a large number of small spherical particles. Moreover, we deduce that the effective mean-field description holds true in the particular limit of vanishing surface-area density of particles.

Stratospheric chemistry and aerosol modeling in CAMS with the IFS-CB05-BASCOE-GLOMAP (ICBG) system: evaluation in quiescent conditions and in a volcanic eruption.

2021 ◽  
Author(s):  
Simon Chabrillat ◽  
Samuel Remy ◽  
Graham Mann ◽  
Vincent Huijnen ◽  
Zak Kipling ◽  
...  
Keyword(s):  
Surface Area ◽  
Stratospheric Aerosol ◽  
Heterogeneous Reactions ◽  
Aerosol Layer ◽  
Particle Nucleation ◽  
Stratospheric Chemistry ◽  
Meteoric Smoke ◽  
Forecasting System ◽  
Aerosol Modeling ◽  
Monitoring Service

<p>We present interactive stratospheric aerosol simulations with the ICBG system, a  global tropospheric-stratospheric combined aerosol-chemistry model which is an extension to the ECMWF Integrated Forecasting System (IFS), and is developed as part of the Copernicus Atmosphere Monitoring Service (CAMS). ICBG is the result of the merging of two existing CAMS configurations of the IFS:</p><ul><li>The IFS-GLOMAP tropospheric-stratospheric aerosol microphysics system, which has the GLOMAP-mode aerosol scheme configured for forecast-cycling experiments within the IFS,</li> <li>The IFS-CB05-BASCOE tropospheric (CB05) – stratospheric (BASCOE) chemistry scheme, which is also an established configuration of the IFS within CAMS.</li> </ul><p>During the first phase of CAMS, the stratospheric chemistry scheme IFS-BASCOE was extended to include the stratospheric sulphur chemistry from the UM-UKCA model, with sulphuric acid production rates from IFS-BASCOE passed each timestep to the aerosol scheme IFS-GLOMAP for aerosol particle nucleation and condensation. The aerosol surface area densities (SAD) simulated by IFS-GLOMAP simulated are similarly passed each timestep to the stratospheric chemistry scheme IFS-BASCOE for  heterogeneous reactions. In a recent progression of this strato-tropospheric modelling system, the climatology for meteoric smoke particles (MSP) used in UM-UKCA has also been implemented. Thus the simulated stratospheric aerosol layer comprises not only pure sulphuric particles nucleated homogeneously but also meteoric-sulphuric particles formed from the MSPs.</p><p>We  evaluate the simulated stratosphere aerosol layer in quiescent conditions, comparing it to SAGE-II measurements from the 1998-2002 period. The simulated stratospheric sulfate burden, aerosol extinction, stratospheric aerosol optical depth (sAOD) and surface area density (SAD) agree well with the SAGE-II retrievals. We also show results from ICBG simulations of the volcanic aerosol cloud from a large-magnitude tropical eruption (Pinatubo, June 1991, VEI6) and a medium-magnitude eruption at a northern mid-latitude (Raikoke, June 2019, VEI4).</p>

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