Using science to understand future of water
The first autumn snows draw our eyes up to the high peaks in northern New Mexico every year. Some people simply enjoy the view. For others, that first dusting signals a good ski season to come. And a lot of New Mexicans hope it means we’ll have water in our streams, rivers and reservoirs next year. Lately, that has been less certain, thanks to climate change.
Throughout the Rocky Mountains and beyond, the high-country winter snowpack and the waters that flow from it are vital for healthy ecosystems, successful agriculture and a vibrant economy. With global climate change, scientists know that higher temperatures, and different rain and snow patterns will affect every downstream water-user. When streamflows are low, farmers struggle to irrigate across a vast region of the Southwest; cities face water shortages; hydroelectric power production is jeopardized; and recreational users, such as rafters, kayakers and paddleboarders, get short-changed in the watersport season. A lack of fresh water from snowmelt can also decrease water quantity and quality in the reservoirs, making it dangerous for swimming.
We’re seeing those effects already. But we’re still in the dark about such crucial details as how soil moisture influences the amount of rainfall that actually reaches a river or how airborne dust changes the timing of the spring snowmelt runoff.
By capturing, storing and distributing rain, snow and runoff, mountain watersheds provide a majority of water resources worldwide. With help from scientists, policymakers rely on Earth-system models to predict the timing and availability of these resources and plan their use, but current models feature strong uncertainties about the water flowing into and out of these watersheds as precipitation, evaporation, runoff to streams and rivers, absorption in soil, uptake by plants, and storage in aquifers.
To settle these uncertainties, Los Alamos National Laboratory and its collaborators have launched a unique, largescale research campaign, called the Surface Atmosphere Integrated Field Laboratory (SAIL), near Crested Butte, high in the Colorado Rockies. SAIL is a research campaign funded by the Department of Energy, managed by the DOE Office of Science Atmospheric Radiation Measurement (ARM) user facility and led by Lawrence Berkeley National Laboratory.
Los Alamos leads the overall management and operations of the ARM mobile observatory, which includes a large array of instruments to study the atmosphere. With a team of researchers from a variety of scientific disciplines, national laboratories, universities and government agencies, we’re studying everything about water in the mountains — what falls from the sky, what flows down the Colorado River watershed, and what gets stored in the bedrock.
Over the next nearly two years, we’ll use radars, lidars (remote sensing with lasers), cameras, weather balloons and other state-of-the-art equipment to collect data on precipitation, wind, clouds, aerosols, solar and thermal energy, temperature, humidity, ozone and more. I’ll be studying aerosols. These tiny particles, many times smaller than the width of a human hair, have an outsized effect as they float around in the atmosphere. If you want to see aerosols, just look at the sky — they play a key role in forming clouds. Without aerosols, we wouldn’t even have rain and snow.
By studying the various sources of aerosols in the region, we hope to figure out which ones are important in cloud formation during large precipitation events and storms. Dust and other aerosols also can absorb solar radiation, raising the temperature in clouds or, similarly, snow when deposited on the ground, and they can block sunlight, causing a cooling effect on the Earth below. Getting a better handle on this provides an important puzzle piece in the big picture of water.
It takes a big research project to paint a big picture and SAIL is a uniquely ambitious survey of a mountain watershed. The data we collect will improve earth-system models for a more complete picture of the surface and subsurface water situation of this mountainous area, helping scientists predict the future availability of water. Results will also boost understanding of similar mountain water towers all around the world.
Since a number of communities, including Santa Fe and Albuquerque, depend on the Colorado River watershed for their drinking water, our research will have benefits close to home. Mountains around the world play a similar role for billions of people and we hope our research will help provide water security for everyone in this changing climate.
Allison C. Aiken is a principal investigator on SAIL and an analytical chemist at Los Alamos National Laboratory who specializes in aerosols, field measurements and laboratory studies to better understand processes in the atmosphere and improve their representation in models.