CCGS Des Groseilliers
Canadian Coast Guard Ship Des Groseilliers

Ceilometers are ground-based remote sensing sensors that measure cloud ceilings and vertical visibility. They utilize a laser or another light source to detect backscatter from clouds, precipitation, and aerosols. Ceilometers provide detailed and precise measurements under all weather conditions and are cost-effective to operate. They are commonly used in boundary layer and cloud research.

Generic-Atmospheric State (Gen-AtmsState) refers to non-specific instruments on a platform used for measurements of atmospheric state parameters. These are typically in situ sensors that measure temperature, pressure, humidity, and wind speed/direction. Types of atmospheric state instruments include thermometers, hygrometers, barometers, and anemometers.

The microwave radiometers (MWRs) are ground-based radiometers manufactured by Radiometrics Corporation and operated by the Atmospheric Radiation Measurement (ARM) Research Facility. MWR measures brightness temperature at 23.8 and 31.4 GHz to determine the column amounts of water vapor and liquid water in the atmosphere. MWR has a field of view (FOV) ranging from about 5.9 to 4.5 degrees depending on the channel and typically has a time resolution of 20 seconds for sky-view observations.

The Millimeter-Wavelength Cloud Radar (MMCR) is a ground-based radar developed by the NOAA Environmental Technology Laboratory (ETL) for the Department of Energy (DoE) Atmospheric Radiation Measurement (ARM) sites. MMCR provides long-term observations of radar reflectivity, Doppler velocity, spectrum width, and other radar parameters for precipitating and nonprecipitating clouds up to 20 km above ground level (AGL). It is a vertically pointing, single-polarization radar system that operates at around 35 GHz. MMCR has a beamwidth of 0.2 degrees and typical vertical resolutions of 45 and 90 meters.

The Atmospheric Emitted Radiance Interferometer (AERI) is a ground-based passive interferometer developed by the University of Wisconsin Space Science and Engineering Center (UW-SSEC) for the Department of Energy (DoE) Atmospheric Radiation Measurement (ARM) Program. It uses Fourier transform spectroscopy to measure downwelling thermal infrared emissions from the atmosphere. These measurements can be used to provide profile measurements of atmospheric temperature and water vapor and detect trace gases. AERI operates across the 3.3-19 μm spectral range and up to 25 μm for the extended range version of the instrument. It has an optimal vertical resolution of 100 meters and completes a full sky scan about every 20 seconds.

Generic-Radiometers refer to non-specific radiometers on a platform. These are typically passive microwave radiometers that measure brightness temperature. Radiometers can be used to retrieve temperature and water vapor profiles, soil moisture content, ocean salinity, precipitation and cloud properties, and vegetation.

The Total Sky Imager (TSI) is a ground-based, optical instrument developed by Yankee Environmental Systems (YES), Inc. TSI provides full-color, hemispheric images of the sky during the day using a charge-coupled device (CCD) imager. It also measures fractional sky cover and sun obscuration caused by clouds. TSI can be mounted on mobile platforms such as trailers and research vehicles, enabling it to collect cloud cover data in different locations during field studies.

The Micropulse Lidar (MPL) is a ground-based lidar system used for cloud detection. It measures lidar backscatter at 532 nm to retrieve cloud properties such as cloud top and base height. It can also be used for the detection of aerosols. MPL has a vertical resolution of 15 m and a maximum range of 18 km. MPL can operate autonomously and typically provides 10-second averaged data.

A pyrheliometer is a ground-based passive radiation sensor. It is used to measure direct beam solar irradiance. Pyrheliometers use a thermopile that converts heat from sunlight to an electrical signal to determine solar radiation. Pyrheliometers measure solar radiation in the 200-4000 nm wavelength range.

The Solar Spectral Flux Radiometer (SSFR) is an airborne radiometer developed by the Ames Atmospheric Radiation Group. It measures solar spectral irradiance in the troposphere. SSFR works within the 300-2150 nm wavelength range and offers a spectral resolution of 8-12 nm. It typically collects data at 1 Hz and has a radiometric accuracy of 3%.

A pyranometer is a ground-based or airborne radiation sensor that measures solar irradiance across a hemispherical field of view. It detects the amount of solar energy reaching the surface, capturing both direct and diffuse sunlight. Pyranometers operate within a spectral range of 280-3000 nm. They are most commonly used for solar monitoring, climate research, weather forecasting, agriculture, and energy management.