Is it spring yet? By the end of April, SMAP will begin investigating Arctic topsoil to find the answer. The orbiting laboratory was launched by NASA on January 31, and will provide crucial information about the carbon cycle as it is affected by the progress of the Arctic spring.
The Soil Map Active and Passive satellite will measure the amount of water in the top few inches of soil every two or three days, globally. It will also report if the water is in a frozen or thawed state. These measurements will help scientists follow the processes that link global water, energy and carbon cycles.
This information is particularly important for understanding the carbon cycle as it plays out during the short Arctic growing season. This has been getting longer, a sign of a warmer climate. During the growing season, the great forests surrounding the North Pole use photosynthesis to turn carbon dioxide into organic matter, effectively acting as a carbon sink. By locking up carbon dioxide in plant matter and the soil, they reduce its presence in the atmosphere.
The northern forests of Alaska, Canada, Scandinavia and Siberia cover almost 15% of the earth’s land surface, and knowing the exact length of the growing season there is critical in understanding trends in the carbon cycle. These forests are also remote and inaccessible, and information about the thaw/ freeze cycle, which indicates the beginning and end of the growing season, has been difficult to obtain. The progress of the spring thaw is also highly variable, depending on topography and location.
On the other side of the scale, the warming climate also leads to droughts and wildfires even in the Arctic. Burning forests release large amounts of carbon dioxide into the atmosphere. Knowing the precise balance between the two – forests as carbon dioxide source and sink – is necessary to understanding the carbon cycle and its trends. SMAP’s global measurements will give scientists accurate information needed to to model future changes. Currently available information is unreliable and produces predictions that do not match actual observed patterns.
SMAP data will also help improve weather forecasting, flood and landslide prediction and drought monitoring capability.