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The Art and Science of Making Atmospheric Measurement

By David Troyan, Rotary Club of Riverhead, NY

What do places as far flung as Ponca City, Oklahoma; Barrow and Atqasuk, Alaska; Darwin, Australia; Nauru Island; and Manus Island, Papua New Guinea have in common?  No, there are not Rotary Clubs at each location – Atqasuk, Nauru Island, and Manus Island are all Rotary-less.  The answer is that at each place there is a permanent suite of atmospheric measurement equipment that is part of the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Program.  I am privileged to be a part of this global research program, and proud to share its mission with you.

Looking through the ARM website (enter “ARM clouds” into your favorite search engine and choose the ARM.gov site), you can find that the “the primary goal of the ARM Program is to improve the treatment of cloud and radiation physics in global climate models in order to improve the climate simulation capabilities of these models.”  Boiling this mouthful down to the simplist concepts:  ARM’s purpose is to better understand the roles of clouds and radiation (from heat and light, not nuclear) on weather and climate.  A better understanding of cloud processes can be incorporated into complicated computer models to simulate future climate with stronger scientific justification.  Ten-, fifty-, and one hundred-year simulations of climate (temperature, snowfall, rain totals, etc.) can be more accurate with a more thorough understanding of the real world as it currently exists.

 

Radiosondes -- instrument packages attached to weather balloons -- are frequently launched at all ARM sites (even in Alaska during the winter!).

To meet this goal, long periods of continuous data gathering are needed.  This is why the six permanent ARM sites were established.  ARM has been collecting data from Oklahoma since 1992; from Alaska since 1997; from Manus Island since 1996; from Nauru Island since 1998; and from Australia since 2002.  Data from these sites are checked for accuracy and extensive quality control is performed.  Vast amounts of data from many different instruments are accessible to anybody through the ARM website.  The data archive is housed at Oak Ridge National Laboratory in Tennessee, and since 1992 has collected 41 terabytes (41 trillion bytes!) of data in 6.7 million files. The sites and data infrastructure were designated a national scientific user facility, known as the ARM Climate Research Facility (ACRF) in 2003, for the purpose of providing this unique asset to the broader national and international global change research community.

Most of the data is from various instruments found at each location.  These are not your standard weather instruments that are used to provide five-day forecasts, but are highly specialized research devices.  For example, millimeter cloud radars can detect cloud boundaries, microwave radiometers determine amounts of water vapor and liquid water, Raman lidars measure cloud- and aerosol-related variables, atmospheric emitted radiance interferometers measure the absolute infrared spectral radiance of the sky directly above the instrument.  These sophisticated machines are definitely several steps beyond the typical “thermometer that measures temperature.”   Even so, simple measurements like temperature, barometric pressure, and relative humidity are still needed, and are obtained at ground sites, on towers of various heights, and on weather balloons.

 

An ARM scientist reviews data produced from the Millimeter Cloud Radar.

Several years ago, ARM built a mobile facility with a set of core instruments like at the permanent sites.  The mobile facility is sent to locations across the globe where researchers deem extra measurements should be obtained.  The first deployment of the ARM Mobile Facility took place in 2005 at Point Reyes, California.  A type of cloud – marine stratus – was the subject of investigation for the nine month deployment.  The facility then moved to Niamey, Niger, West Africa for a study of Saharan dust and West Africa monsoon conditions in 2006.  Precipitation was the focus of the 2007 deployment in Heselbach, Germany.  Aerosols are currently being studied in 2008 at Shouxian, China.

The mission of the ARM Program has remained the same, with small changes in research focus as advances and new discoveries have occurred.  What remains most impressive about the ARM Program is the original commitment to obtain a long record of atmospheric conditions using the best instruments available.  Free and global access to the unique ARM data sets has been a tremendous asset to the scientific community.  Research results that have used ARM data have appeared in prestigious scientific journals including Science, Nature, Journal of Geophysical Research, Journal of Climate, and the Bulletin of the American Meteorological Society.

Another distinguishing feature of the ARM program is the participation of a large number of institutions.  National labs with large roles are Argonne National Lab (Illinois), Brookhaven National Lab (New York),  Lawrence Berkeley and Lawrence Livermore National Lab (California),  Oak Ridge National Lab (Tennessee), Pacific Northwest National Lab (Washington), Sandia and Los Alamos National Labs (New Mexico), and the National Renewable Energy Lab (Colorado).  National Oceanic and Atmospheric Administration and Nation Aeronautics and Space Administration are both important participants in the ARM program.  Many private and public universities likewise contribute much energy, expertise, and enthusiasm to ARM.

 

An example of a tropical anvil cloud. ARM studies clouds of all types.

Rotarians around the world may find themselves within close proximity to some of the many experts associated with the ARM Program.  The scientist or technician may be setting up the Mobile Facility in the Azores, returning to Niger for additional measurements, doing a field study near Ponca City, Oklahoma, consulting with colleagues in Boulder, Colorado, or repairing an instrument in Barrow, Alaska.  Or, they may be developing models, theories, or instrumentation while working at universities in cities such as Stony Brook, New York; Tallahassee, Florida; State College, Pennsylvania; Madison, Wisconsin; Grand Folks, North Dakota; or New Brunswick, New Jersey.   ARM personnel are very much like Rotarians…they seem to be everywhere doing meaningful and exciting work.

The author wishes to thank Lynne Roeder of Pacific Northwest National Lab for her help in editing this article.

All photos are courtesy of the U.S. Department of Energy’s Atmospheric Radiation Measurement Program.