Sunshine. It rejuvenates our gardens, illuminates our homes, and lightens our moods. In short, it makes this third planet more than a lifeless rock. But, despite our obvious dependence on our nearest star, there is a more sinister aspect to the sun.
Wrinkles, skin cancer, cataracts, thickening of the cornea, even suppression of our immune systems have all been linked to the sun, or more specifically, to the invisible ultraviolet (UV) radiation that emanates from it. In addition to threatening our health and vanity, UV radiation may threaten our food supply by impacting plant growth and productivity.
There is growing evidence that we're being exposed to more damaging UV rays than ever before because of the depletion of the Earth's protective ozone layer. The Earth's atmospheric blanket also provides some protection from UV. But in the West, that protection diminishes in the region's higher altitudes where skiers, snowboarders, hikers and campers-not to mention fragile alpine ecosystems-may suffer the quickest and greatest damage.
To examine those aspects, scientists from Nevada's Desert Research Institute are working in DRI's unique Storm Peak Laboratory at atop 10,525-foot Mt. Werner in northwest Colorado. The laboratory has joined a nationwide network of UV-B monitoring sites, with equipment funded in part by the U.S. Department of Agriculture.
Dr. Melanie Wetzel of DRI's Division of Atmospheric Sciences is one of many scientists worldwide who are conducting research to learn more about UV radiation, specifically how it changes under different environmental conditions and from region to region. She's helping to provide the data and analysis needed to assess the potential impacts of increasing UV radiation on agriculture, forest productivity, and the people who spend time through work or recreation in rural and forest environments.
"The Storm Peak Laboratory's location provides new observational data from an alpine forest ecological zone," explains Wetzel. "It's important that the sites in the network represent a variety of ecosystems since UV radiation is influenced by many different factors, including elevation, humidity, snow and cloud cover, and the concentrations of atmospheric particulates and gases."
Of most concern, for health reasons, is the part of the ultraviolet spectrum known as UV-B. The project uses sensors to measure solar radiation at several different wavelengths to track the intensity and character of UV radiation reaching us under a variety of meteorological conditions.
"Those who live in the West often get higher doses of ultraviolet radiation due to the clear skies, low humidity, and higher altitude," says Wetzel. "Also, reflection by snow and clouds is stronger for UV radiation than visible light."
The growing archive of measurements will provide valuable data for testing computer-based model calculations of UV flux in clear and cloudy conditions, verifying satellite-derived mapping of downward UV radiation and atmospheric ozone amount, and improving daily forecasts of UV exposure in mountainous terrain.
A long-term research goal at DRI is to make comparison studies of UV climatology and ecological impacts among multiple western sites such as the Sierra Nevada Mountains and the Rocky Mountains.
At its high elevation, the Storm Peak Laboratory is frequently immersed in cloud and provides an ideal opportunity for simultaneously sampling the cloud particle conditions as well as the flux of atmospheric radiation. The sophisticated equipment used at Storm Peak Lab lets researchers look in detail at how such environmental variables affect UV radiation. With several measurements taken every minute, researchers can see how passing clouds, or the amount of atmospheric ozone or airborne particles, affect the flux of ultraviolet radiation.
DRI's new radiation monitoring instrumentation also has great potential for collaborative research on how that radiation affects living things. "We are collecting the atmospheric radiation measurements to establish a long-term database," says Wetzel, "and now the challenge is to examine how the observations relate to biological and human impacts-to connect it to the ecological risks."
You don't have to ask your dermatologist-or your neighborhood ecologist-to confirm that this is a serious subject. The work of Wetzel and other UV researchers is shedding some very important light on the dark side of the sun.