Infrastructure Support for DOE's Atmospheric Science Program
Purpose
This project at Pacific Northwest National Laboratory provides basic information about the meteorological conditions under which the Department of Energy's Atmospheric Science Program (ASP) http://www.asp.bnl.gov field campaigns are conducted as well as ground truth observations of selected aerosol properties.
Instruments that may be provided include a 915 MHz radar wind profiler, a Doppler sodar, a rawinsonde system, surface weather stations for measuring temperature, wind velocity, and humidity, two 3-λ nephelometers, an optical particle counter (PCASP-100x), two condensation particle counters (CPCs), and two 3-λ particle soot absorption photometers (PSAPs). Particle sizing for the nephelometers, PSAPs, and CPCs is done using 1 μm and 10 μm impactors. Members of the ASP science team who require these data to help interpret results from anticipated field campaigns are able to request the use of these instruments in their proposals.
The combination of a surface station, a Doppler sodar, and a radar wind profiler yields wind velocity profiles from a few meters above the surface to altitudes on the order of 3 km or more under favorable conditions. With more specialized data processing, it also is possible to extract additional information about various turbulence characteristics of the atmosphere, e.g., turbulent kinetic energy dissipation rates.
The addition of a rawinsonde system gives temperature and humidity profiles throughout the depth of the boundary layer and to heights of 10 km or more above ground level, if desired. Using GPS tracking of the rawinsonde, wind velocities can be obtained over a similar range. Such information is required to describe the transport and diffusion of aerosols released into or produced in the atmosphere and also is needed to establish the accuracy of numerical simulations of chemical and aerosol processes.
The scattering and absorption coefficients and the size distribution of aerosols compose a basic set of aerosol characteristics that are useful in a wide variety of applications. Ground-based measurements of these quantities are valuable in themselves, and they also complement measurements that are normally made on the Gulfstream-1 aircraft used in ASP field campaigns. Our deployment of the PCASP-100x, the PSAPs, and the nephelometers will provide the means for acquiring these data.
Deployments
The complement of instruments deployed in a given year depends on the needs of the ASP and on the funding level that is available. Normally this project will serve a single major field campaign per year. The next scheduled deployment is to the Mexico City area for the MAX-Mex/MILAGRO field campaign in March 2006.
Meteorological Instruments
| Instrument | Available Systems | Variable(s) | Reporting Interval |
|---|---|---|---|
| Rawinsonde System (Vaisala Digicora III) | 1 | Wind speed and direction, P, T, RH | Up to 5 launches day-1 for up to 20 days in a 4-week period |
| Sodar (Scintec FAS-64) | 1 | Wind speed and direction up to 500 m AGL | 10-60 min, based on consultation with users |
| 915-MHz Wind Profiling Radar/RASS (Vaisala) | 1 | Wind speed and direction to 4 km; virtual temperature to 1 km | 30 min, based on consultation with users |
| Surface Meteorological Station (Campbell) | 2 | Wind speed and direction, P, T, and RH at 2 m | 5 min, based on consultation with users |
Aerosol Instruments
| Instrument | Available Systems | Variable(s) | Reporting Interval |
|---|---|---|---|
| Nephelometer (TSI) | 2 | Total scattering; Backscatter λ=450 nm, 550 nm, 700 nm | 1 sec, with 5-min cycles for each impactor range |
| Particle Soot Absorption Photometer (Radiance Research) | 2 | Light absorption coefficient λ=470 nm, 530 nm, 660 nm | 10 sec, with 5-min cycles for each impactor range |
| Passive Cavity Aerosol Spectrometer Probe-PCASP (Droplet Measurement Technologies) | 1 | Particle size distribution 10-40 bins over 0.1-3 μm radii | variable |
| Condensation Particle Counter; sizing by 1 μm and 10 μm impactors (TSI CPC 3010) | 2 | Counts of particles for D ≤ 1μm and D ≤ 10μm | 1 sec, with 5-min cycles for each impactor range |
For more information, contact Will Shaw
