Microbarometers are sensitive barometers that can measure air pressure with high precision. Microbarometers typically have a resolution of microbars (μbar) or pascal

Pascal (unit)

The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...

s (Pa), while ordinary barometers can only resolve in hectopascals (hPa) or millibars (mbar). Recording microbarometers, or microbarographs, distributed around the world are planned to be used to monitor compliance with the Comprehensive Nuclear-Test-Ban Treaty (upon entry into force) by detecting the infrasound

Infrasound

Infrasound is sound that is lower in frequency than 20 Hz or cycles per second, the "normal" limit of human hearing. Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high...

 signature of a nuclear explosion

Nuclear explosion

A nuclear explosion occurs as a result of the rapid release of energy from an intentionally high-speed nuclear reaction. The driving reaction may be nuclear fission, nuclear fusion or a multistage cascading combination of the two, though to date all fusion based weapons have used a fission device...

, which can propagate for very long distances. By analyzing the data received at several of these monitoring stations, the location and yield of the explosion can be determined.

A microbarometer used as a pressure altimeter would be able to resolve altitude differences on the order of centimeters, but for the presence of infrasonic noise such as microbaroms.