Storm Peak Laboratory Investigates Air Quality from Regional and Long Range Sources

The Desert Research Institute (DRI) operates a high elevation facility, Storm Peak Laboratory (SPL), located near Steamboat Springs, Colorado at an elevation of 3210 m. The SPL mission statement is “To ensure that the laboratory will continue to integrate climate research and education by advancing discovery and understanding within the field of pollution, aerosol and cloud interactions”. SPL provides an ideal location for long-term research on the interactions of atmospheric aerosol and gas- phase chemistry with cloud and natural radiation environments. The ridge-top location produces a daily transition from free tropospheric to boundary layer air which occurs near midday in both summer and winter seasons. During winter, SPL is above cloud base 25% of the time,

providing a unique capability for studying aerosol-cloud interactions. A comprehensive set of continuous aerosol measurements was initiated at SPL in 2002

SPL includes an office-type laboratory module for computer and instrumentation set up with outside air ports and cable access to the roof deck, a cold room for precipitation and cloud rime ice sample handling and ice crystal microphotography, a 150 m2 roof deck area for outside sampling equipment, a full kitchen and overnight living accommodations. The laboratory has been equipped recently with state-of-the art broadband high speed internet connection with a wireless network for visiting computers including network printers, and three workstations for common use. SPL is also part of several climate observational networks including the Western Regional Climate Center, the Regional Atmospheric Continuous CO2 Network in the Rocky Mountains, and the U.S. Department of Agriculture Ultraviolet-B (USDA UV-B) monitoring and research center.

Instruments available at SPL include the following: 1) TSI Scanning Mobility Particle Sizer (SMPS) (model 3936) coupled with a TSI model 3022A condensation particle counter (CPC); 2) stand-alone TSI model 3010 CPC for particles with diameters larger than 10 nm; 3) stand-alone TSI model 3025 CPC for particles with diameters larger than 3 nm; 4) TSI model 3321 Aerodynamic Particle Sizer (APS) for particles with diameters larger than 540 nm; 5) Droplet Measurement Technologies, Inc. (DMT) CCN-100 counter; and 6) complete meteorological station, including temperature, pressure, wind speed and direction, and relative humidity with Campbell Scientific, Inc. (CSI), Met One and Vaisala sensors interfaced to a CSI CR10 data logger. Instruments are controlled by PC computers linked in a secure intranet with broad-band communication to DRI and the outside world. Most instrumentation can be monitored remotely via the Storm Peak web-site.

SPL works with the Steamboat Ski Corp. to maintain six meteorological stations across the mountain. These stations measure temperature, dew point temperature, wind speed, and wind direction along an altitude gradient from the valley (i.e., the town of Steamboat Springs, elevation 2100 m AMSL) to the Storm Peak Laboratory (3210 m AMSL). These stations thus provide a vertical profile of meteorological conditions which compared well with those measured with radiosondes launched by the National Center for Atmospheric Research in 2002 (Wetzel and Borys, 2004). These data allow investigators to identify periods when the laboratory is within the surface inversion or in the free troposphere.

Using SPL as the point of observation, recent studies were conducted to test if Asian long-range transport (ALRT) of pollutants and dust can be observed significantly inland in North America. Measurements of gaseous elemental mercury (GEM) from October 2006 to May 2007 will be presented. One very pronounced GEM enhancement occurred between March 31 and April 6, 2007. Carbon Monoxide and Ozone levels increased with GEM during the event. Calculated 10-day back-trajectories (Hysplit) indicate that air masses measured at SPL had a likely source area of Eastern Asia. Our data indicate that mercury loads from ALRT are not limited to the coastal areas but can be carried far inland and affect areas such as the Rocky Mountains. In April 2008 measurements of GEM resumed at SPL for a three-month study. In addition to GEM measurements of reactive mercury were setup as well. Results of both studies will be presented.

During the first two weeks of April 2008, a pilot study was conducted at SPL to investigate aerosol and cloud properties at Storm Peak. The Scientific Questions addressed by this study are:

1) What organic compounds are measured in the free troposphere from Storm Peak?

2) Is there a difference between measurements in the boundary layer and the free troposphere?

3) Are there any correlations between the particle measurements and the cloud properties? Other measured variables?

4) Can we identify specific sources of aerosols measured at the site? Can we determine the lifetime of the aerosols measured at the site?

5) What types of microorganisms are found in the atmosphere at Storm Peak?

6) Do we find different types of microorganisms within clouds versus in cloud-free atmosphere?

7) Do we find ice-nucleating bacteria in the atmosphere at Storm Peak?

8) Is there any correlation between the organic composition of the aerosols (or clouds) and the measured microorganisms at Storm Peak?

Initial results from this pilot study will be presented.