Current activity includes operation and maintenance, including sporadic repair as required, data retrieval, and data analysis. 14.5 Atmospheric transparency Pressure broadened molecular spectral lines, principally of tropospheric water vapor, make the atmosphere semi-opaque at millimeter and submillimeter wavelengths. The translucent atmosphere radiates thermally, which increases the system noise, and attenuates incoming radiation, which decreases the signal. The 225 GHz tipping radiometer is the benchmark instrument for site characterization. It measures the atmospheric transparency every 10 minutes and the stability of atmospheric emission every fifth hour.
Operation is automatic.
Daily and monthly data summaries are posted. The data are made available to interested parties in machine readable form. Current activity includes operation and maintenance, including sporadic repair as required, data retrieval, and data analysis. This instrument is based on an ambient temperature, pyroelectric detector. The spectral response is defined by a resonant metal mesh.