Date ( Publication )

2011-04-01T19:01:00

Purpose

Multi-angle absorption photometer (MAAP 5012, Thermo Electron Corporation) measuring aerosol light absorption properties, corresponding to Black Carbon content ( data acquisition system modified by ISAC-CNR).This instrument measures 15 the absorption coefficient of aerosol deposited on a glass fibre filter tape, also removing the scattering effect at different angles, which can interfere with optical absorption measurements. The continuous monitoring of atmospheric composition represents a necessary activity to well evaluate the impact of the human activities on the environment. The station has been installed with the aim to promote continuous scientific observations in key high-mountain regions able to contribute to knowledge on regional and global climate change.

Specific aims of the measurements conducted at this station are:

- to obtain a chemical climatology of aerosol properties (optical, chemical and physical) at an high elevation site in Hymalaias over the duration of the SHARE-Asia experiment;

- to evaluate temporal trends of aerosol composition as a function of sources/transport;

- to evaluate the variations of radiative forcing produced by aerosols;

- to study the background ozone behavior and evaluate the contributions of stratospheric ozone intrusions as well as long range and regional transport of polluted air masses;

- to monitor the concentration trends of major Halocarbons and greenhouse gases.

Status

Completed

Maintenance and update frequency

As needed

Keywords

• SHARE , Network , Station , High Altitude

Keywords

• WMO , GAW

Keywords

• CEOP

Keywords ( Place )

• Nepal

Keywords ( Theme )

• aerosol , black carbon

Keywords ( Theme )

• air , research , pollution , ecosystems , landscape , natural areas , climate

Use limitation

No conditions apply

Access constraints

Copyright

Other constraints

Character set

UTF8

Topic category

• Climatology, meteorology, atmosphere
• Environment
• Geoscientific information

Supplemental Information

Reference system identifier

EPSG / WGS 84 (EPSG:4326) / 7.4

Topology level

Geometry only

Geometric object type

Point

Geometric object count

1

OnLine resource

SHARE Geonetwork portal  

SHARE Geonetwork portal

OnLine resource

ISAC EVK2-Nepal Climate Observatory - Pyramid website  

ISAC EVK2-Nepal Climate Observatory - Pyramid website

OnLine resource

GAWSIS (Global Atmosphere Watch Station Information System) report about Nepal Climate Observatory - Pyramid  

GAWSIS (Global Atmosphere Watch Station Information System) report about Nepal Climate Observatory - Pyramid

OnLine resource

Official website of CEOP-HE (Coordinated Energy and water cycle Observation Project - High Elevation)  

Official website of CEOP-HE (Coordinated Energy and water cycle Observation Project - High Elevation)

OnLine resource

thermoscientific5012_maap.pdf  

Product Specifications MAAP 5012

Hierarchy level

Series

Other

data: Black Carbon

Statement

The Thermo Scientific Multi-Angle Absorption Photometer (MAAP) - 5012 Model measures loading of black carbon in the atmosphere using a radiative transfer scheme to particle loaded glass fiber filters. The MAAP is based on the principle of aerosol-related light absorption and the corresponding atmospheric equivalent black carbon (EBC) mass concentration. The Model 5012 uses a multi angle absorption photometer to analyze the modification of scattering and absorption in the forward and backward hemisphere of a glass-fibre filter caused by deposited particles. The internal data inversion algorithm of the instrument is based on a radiation transfer model and takes multiple scattering processes inside the deposited aerosol and between the aerosol layer and the filter matrix explicitly into account (see Petzold et al., 2004).The sample air is drawn into the MAAP and aerosols are deposited onto the glass fibre filter tape. The filter tape accumulates the aerosol sample until a threshold value is reached, then the tape is automatically advanced. Inside the detection chamber a 670-nanometer light emitting diode is aimed towards the deposited aerosol and filter tape matrix. The light transmitted into the forward hemisphere and reflected into the back hemisphere is measured by a total of five photo-detectors. During sample accumulation, the light intensities at the different photo-detectors change compared to a clean filter spot. The reduction of light transmission, change in reflection intensities under different angles and the air sample volume are continuously measured during the sample period. With these data and using its proprietary radiation transfer scheme, the MAAP calculates the equivalent black carbon concentration (EBC) as the instruments measurement result. Using the specific absorption cross section ðBC = 6.6 m2/g of black carbon at the operation wavelength of 670 nm, the aerosol absorption at that wavelength can be readily calculated.

gmd:MD_Metadata

File identifier

e9ec062a-f1f2-49b2-9582-c50987c3e73b   XML

Metadata language

eng

Character set

UTF8

Parent identifier

d83f95af-91e7-443e-974f-c7e1f0be700d

Hierarchy level

Series

Date stamp

2011-09-26T14:24:26

Metadata standard name

ISO 19115:2003/19139

Metadata standard version

1.0