The Greenhouse Gas Measurments Program supports the following projects in the Communications Technology Laboratory's RF Technology Division.
Toward a Global Microwave Standard (D. Walker) Much of what is known about the state of Earth's atmosphere – and much of what appears on the evening weather forecast as well – comes from satellite-based remote sensing of microwave radiation at different levels of the atmosphere. Microwave measurements are generally reported as the apparent temperature of the object being monitored. Yet, until recently, there was no accepted brightness-temperature (radiance) standard for microwaves that could be used for authoritative calibration of microwave sensors, for resolving discrepancies between observation by different satellites, or for comparing the results of one observing program with another. Recent NIST efforts have established a microwave brightness standard, and NIST is working toward providing a calibration service based on this advance.
Thermal Noise Metrology (D. Walker) Noise power is also the quantity that is measured in passive remote sensing, such as that used to measure properties of Earth's surface from satellites or airplanes. The growing importance of such measurements for climate monitoring, weather forecasting, agriculture, and other applications has highlighted the need for better calibration techniques, smaller uncertainties, and compatibility between results from different instruments.
NIST Quantum Probe Enhances Electric Field Measurements (J. Gordon) NIST research has demonstrated a technique based on the quantum properties of atoms that directly links measurements of electric field strength to the International System of Units (SI). The new method can potentially improve the sensitivity, precision and ease of tests and calibrations of antennas, sensors, and biomedical and nano-electronic systems and facilitate the design of novel devices.