Aerosol optical properties monitoring system

    Column Aerosol Optical Depth

SACOL's Instruments The observations of aerosol optical depth (AOD) are made using an automatic sun tracking photometer (CE318N-VPS8, Cimel) with 8 filters in the visible and near infrared at wavelengths of 440, 670, 870, 870,870, 936 and 1020 nm. The instrument calibration is carried out once per year. The total column water vapor, ozone and aerosols properties can be derived. It is also very useful to determine the atmospheric correction of satellite data. The graph (right) shows the daily AOD in SACOL.


    Aerosol Size Distribution

SACOL's InstrumentsAerosol vertical distribution (represented by extinction coefficient) is measured using a Micro-Pulse Lidar system (MPL-4, Sigma Space). The MPL has one measurement channel at 527 nm, that records backscatter signals up to 20+ km. From the relative backscatter profile, other data products are possible including multiple cloud deSACOL's Instrumentscks, cloud and layer boundaries, as well as aerosol extinction and backscatter profiles. Aerosol vertical distribution is also measured by a CAMLTM Micro Lidar (CE 370-2, CIMEL & CNRS). It is a portable, eye safe and unattended backscattering lidar that features the ability to profile atmospheric cloud and aerosol structures. Such information is critical to operational field and lab applications related to meteorology and environment.


SACOL's Instruments

    Aerosol Vertical Distribution

Aerodynamic diameter as well as relative light-scattering intensity of aerosol particles that are between 0.5 and 20 m in diameter are measured using an aerodynamic particle sizer (APS-3321, TSI).


    Aerosol Scattering Coefficient

SACOL's InstrumentsThe observations of aerosol scattering coefficient are performed using three single wavelength Integrating Nephelometers (M9003, ECOTECH, 450, 550 or 700 nm, right), and a TSI three wavelengths (450, 550 and 700nm) Integrating Nephelometer (Model 3563, TSI, below). These two kinds of nephelometer share the same principle.
SACOL's InstrumentsA TSI nephelometer is particularly well-suited for measurements related to climate, visibility, and air quality. The graph (right) shows the daily change of the mean Scatter Coefficients over Xigu District in Lanzhou City (Zhang et al, 2004), which is consistent with the change of concentration of PM10.


SACOL's Instruments

    Aerosol Absorption Coefficient

SACOL's Instruments
The aerosol light-absorption properties are measured at seven wavelengths (370, 470, 520, 590, 660, 880 and 950 nm) by an aethalometer (Model AE-31, Magee Sci.). The primary propose of this instrument is to measure the aerosol black carbon (BC) concentration in the atmosphere.