G-II
Gulfstream II

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

The Nevzorov Probe is an in situ airborne hot-wire probe that measures clouds' liquid water content (LWC) and total water content (TWC). It determines LWC and TWC by detecting heat loss from its two sensors due to evaporation of cloud water and convective heat losses. Operating at a constant temperature of 90 degrees Celsius, it can measure LWC and TWC in the range of 0.005-3 grams per cubic meter. The Nevzorov Probe provides measurements every second with an accuracy of 10%.

The King Probe is an in situ airborne cloud instrument developed by Warren King (Commonwealth Scientific and Industrial Research Organisation) and manufactured by Particle Measuring Systems (PMS) and Droplet Measurement Technologies (DMT). It measures cloud liquid water content (LWC) by detecting the heat released during droplet vaporization. It operates at a constant temperature of approximately 100°C and outputs data at 1 to 10 Hz. The probe is commonly used in studies of cloud microphysics and aircraft icing.

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

The Particulate Volume Matter (PVM-100A) is an in situ airborne cloud probe manufactured by Gerber Scientific. It measures liquid water content and the effective radius of cloud droplets by measuring the scattering intensity, which is proportional to droplet density and particle surface area density. The PVM-100A operates at 780 nm and has a measurement rate of up to 5000 Hz. It can measure droplets with diameters of 3-50 μm. The ground-based model of this instrument is the PVM-100.

The Cloud Aerosol and Precipitation Spectrometer (CAPS) is an in situ airborne spectrometer manufactured by Droplet Measurement Technologies. It integrates the Cloud Imaging Probe (CIP), the Cloud and Aerosol Spectrometer (CAS), and the Hotwire Liquid Water Content (LWC) Sensor into a single instrument. CAPS measures the size distribution of aerosol, cloud, and liquid droplets for particles between 50 and 1600 μm, with a time resolution of 1 Hz. It can also capture images of cloud particles and provide measurements of temperature, pressure, and LWC.

W-band radars are highly sensitive radars used for atmospheric research. They operate around 94-95 GHz, enabling the detection of small water droplets. W-band radars are used for cloud and precipitation studies because they provide more detailed observations than typical weather radars. They can be deployed on research vessels, aircraft, and mobile ground-based platforms.

Dropsondes, also known as dropwindsondes, are in situ instruments released from aircraft. They are equipped with Global Positioning System (GPS) receivers and sensors that collect vertical profiles of pressure, temperature, humidity, wind speed, and wind direction. Dropsondes are important during field investigations because they enable researchers to collect vertical profiles in remote locations and during severe weather. Typically, dropsondes have a vertical resolution of 5 meters and provide wind speed and direction measurements every 0.25 seconds, while temperature, pressure, and humidity are recorded every 0.5 seconds.

Rosemount Temperature Probes are in situ airborne temperature sensors manufactured by Rosemount, Inc. They provide atmospheric temperature measurements and are typically used to collect flight-level meteorological observations. Rosemount Temperature Probes consist of temperature transmitters, thermocouple sensors, resistance temperature detectors, and other temperature sensors.

The Lyman-alpha Hygrometer is an in situ hygrometer designed for deployment on airborne or ground-based platforms. It measures water vapor absorption at the Lyman-alpha wavelength (121.6 nm) of atomic hydrogen to determine the total water content in the atmosphere. It has a detection limit of 0.1 ppmv and a typical data acquisition rate of 1 second. The Lyman-alpha hygrometer provides water vapor measurements with 6% accuracy and 5% precision.

The Forward Scattering Spectrometer Probe (FSSP) is an in situ airborne optical particle counter developed by Particle Measuring Systems, Inc. It determines particle size distribution by measuring the light intensity scattered by individual particles within a cloud. The FSSP detects particles from 0.5 to 47 μm in diameter. It operates at a wavelength of 633 nm and typically samples at 1 Hz.

The 2D-C/P Hydrometeor Imaging Probe (2D-C/P) is an in situ, airborne instrument that captures images of hydrometeors. It records these images by detecting the illuminated or shadowed states of the photodiode array as the hydrometeors' shadows pass over it. 2D-C/P also provides measurements of particle size distribution, cloud droplet concentration, and hydrometeor shape. Typically, 2D-C/P probes have an image resolution of 25 micrometers and can image hydrometeors with diameters up to 1600 micrometers.

Video cameras capture footage of various phenomena for research. They are used on aircraft to provide continuous views of weather and terrain below the flight path. Video cameras are also employed to verify the aircraft's flight track. Additionally, they are deployed at field sites to monitor changes in vegetation, land cover, clouds, air quality, glaciers, and other Earth science phenomena.