Member Price:
$5.00
Nonmember Price:
$15.00
|
Your Price: $15.00
Order Code:
Add to Cart |
Eighty-four CASTNet sites are operated across the United States. Each site is equipped with
filter packs and meteorological instruments. The filter packs measure weekly concentrations of
sulfur and nitrogen gaseous and aerosol air pollutants. The meteorological sensors measure wind
speed and direction, standard deviation of wind direction, temperature and temperature lapse
rate, relative humidity, solar radiation, surface wetness, and precipitation.
The primary purpose of the meteorological measurements is to provide input to a computer
model called the Multi-Layer Model (MLM) in order to calculate hourly deposition velocities.
The deposition velocities are combined with the measured air pollutant concentrations to
simulate atmospheric dry deposition. MLM input requires several simultaneous valid
meteorological measures. Consequently, the data completeness requirements for the
meteorological measurements are rigorous. Furthermore, precision and accuracy requirements
are also rigorous.
This paper discusses the completeness, precision, and accuracy statistics for the CASTNet
meteorological data over the 16-year history of the network and the experience in meeting the
requirements for MLM model input and subsequent flux estimates. Completeness of all
meteorological measurements over the history of the network was approximately 94 percent.
Precision, which is based on simultaneous hourly data from collocated instruments, ranged from
2 to 9 percent. Accuracy results, which were based on NIST-traceable instrument audits, were
satisfactory. The overall performance of the meteorological instruments allowed the satisfactory
simulation of atmospheric dry deposition and the compilation of a long-term database to estimate
trends in deposition.
The meteorological measurements are also used to gauge relationships between regional air
quality and synoptic meteorological events, e.g., how tropospheric ozone is related to solar
radiation, temperature, and precipitation. The data are also used to analyze air pollution episodes
and understand the relationship between deposition and meteorological conditions. Finally, the
meteorological data are used to assess long-term changes in annual and seasonal meteorological.
|
CNumber:
ACE 2003 - San Diego, CA June 22-26, 2003
|
|
Publication Type:
Proceedings
|
|
Publication Date:
June 2003
|
|
|
|
