The Cloud and Land Surface Interaction Campaign (CLASIC07) was a NASA-led project aimed at understanding how land surface processes affect cumulus convection. CLASIC07 had a single deployment in the summer of 2007 across the Southern Great Plains. Five aircraft and one helicopter were used to collect measurements of cloud and surface properties, heat, moisture, and carbon fluxes, along with various other meteorological and atmospheric chemistry parameters. Satellite overpasses coincided with aircraft measurements, while ground instruments provided “ground truth” estimates. CLASIC07 was funded by NASA’s Water and Energy Cycle Program.
The ER-2 Doppler Radar (EDOP) is an airborne X-band radar designed to operate on the nose of the ER-2 aircraft. It measures radar reflectivity, Doppler velocity, and spectrum width to characterize precipitation systems. EDOP operates at a 9.6 GHz frequency and provides data at a rate of 2 Hz. It has a typical gate spacing of 75 m and a beamwidth of 2.9 degrees. EDOP has been replaced by the EXRAD radar.
The MODIS Airborne Simulator (MAS) is an airborne multispectral spectrometer designed to simulate the satellite instrument Moderate-Resolution Imaging Spectrometer (MODIS). MAS operates over 50 spectral channels in the 0.55 to 14.2 μm range, providing high-resolution images of clouds and surface features. It has a horizontal spatial resolution of 50 meters and a swath width of about 36 kilometers at an altitude of 20 km at nadir. Its scan rate is 6.25 Hz, with each scan line containing 716 pixels.
The Cloud Radar System (CRS) is an airborne W-band (94 GHz) polarimetric Doppler radar designed for the NASA ER-2 aircraft. CRS provides radar observations of clouds and precipitation from the surface to the lower stratosphere. It has a horizontal resolution of 150 m and a horizontal sampling interval of 50 m. Its vertical resolution is 100 m with a vertical sampling interval of 37.5 m.
The Polarimetric Scanning Radiometer (PSR) is an airborne passive microwave imaging radiometer developed by Georgia Tech and NOAA. It captures polarimetric microwave emission images of Earth to analyze ocean and land surface features, precipitation, ice, and clouds. PSR operates across four microwave channels: 10.7 GHz, 18.7 GHz, 37 GHz, and 89 GHz. The PSR/A version includes an extra dual-polarimetric channel at 21.5 GHz. Operating at an altitude of 22,000 feet above sea level, PSR has a spatial resolution ranging from 0.3 to 2.2 km, depending on the frequency band and scan mode.
Earth Science > Spectral/engineering > Microwave > Brightness Temperature
The Cloud Physics Lidar (CPL) is an airborne lidar system designed specifically to provide multi-wavelength measurements of cirrus clouds, sub-visual cirrus clouds, and aerosols. It measures lidar backscatter at three wavelengths: 355 nm, 532 nm, and 1064 nm. These measurements can be used to determine cloud optical depth, particle size distribution, extinction profiles, aerosol layers, and other properties. CPL has a vertical resolution of 30 m and a typical horizontal resolution of 200 m. It has a measurement sampling rate of 1 Hz.
The Passive Active L- and S-band Sensor (PALS) is a combined airborne polarimetric radiometer and radar developed by NASA’s Jet Propulsion Laboratory (JPL). It was designed to evaluate the advantages of merging passive and active remote sensors for measuring ocean salinity and soil moisture. Both the radiometer and radar in PALS operate across the L-band (1.41 GHz, 1.26 GHz) and S-band (2.69 GHz, 3.15 GHz) frequencies to measure brightness temperature and radar backscatter related to ocean salinity and soil moisture. Depending on the aircraft's altitude, PALS has a spatial resolution ranging from 600 to 1500 meters. Its design allows for installation on various aircraft and is typically used to validate observations from the Aquarius and SMAP satellite observations.
Generic-Chemistry Related Sensors (Gen-Chemistry) refers to non-specific instruments on a platform used for atmospheric chemistry measurements. These are typically in situ analyzers that measure various chemical compounds such as trace gases, halocarbons, volatile organic compounds, nitrates, aerosols, and other chemical species. Measurements can include mixing ratio, composition, particle size, optical properties, and particle size distribution.
The Cloud Absorption Radiometer (CAR) is an airborne multichannel scanning radiometer developed by the Goddard Space Flight Center (GSFC). CAR provides measurements of scattered radiance and bidirectional surface reflectance across 14 spectral bands in the visible and near-infrared wavelengths (0.34-2.30 µm). It also captures imagery of cloud and surface features on Earth. CAR has a scan rate of 1.67 Hz (100 rpm) and a spatial resolution of 4 meters at nadir, at an altitude of 200 meters above ground.
Earth Science > Atmosphere > Clouds > Cloud Radiative Transfer
The Polarimetric Scanning Radiometer (PSR) is an airborne passive microwave imaging radiometer developed by Georgia Tech and NOAA. It captures polarimetric microwave emission images of Earth to analyze ocean and land surface features, precipitation, ice, and clouds. PSR operates across four microwave channels: 10.7 GHz, 18.7 GHz, 37 GHz, and 89 GHz. The PSR/A version includes an extra dual-polarimetric channel at 21.5 GHz. Operating at an altitude of 22,000 feet above sea level, PSR has a spatial resolution ranging from 0.3 to 2.2 km, depending on the frequency band and scan mode.
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.
Earth Science > Atmosphere > Atmospheric Water Vapor
Earth Science > Atmosphere > Atmospheric Pressure
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Humidity
Earth Science > Atmosphere > Atmospheric Temperature > Surface Temperature > Air Temperature
Digital cameras are used to provide imagery for research applications. Cameras are used on aircraft to collect aerial imagery for mapping and surveying, environmental monitoring, cloud observations, agriculture, geological studies, and other Earth science applications. They are also used at field sites to capture visual observations to monitor changes in land cover, vegetation, clouds, air quality, glaciers, and other phenomena.
Eddy Covariance Flux Towers are in situ micrometeorological surface towers. They are equipped with gas sensors to continuously measure the trace gas fluxes between the land surface and the atmosphere. Eddy Covariance Towers are typically used to measure fluxes for carbon dioxide (CO2), methane (CH4), and water vapor (H2O). These towers are also equipped with various meteorological sensors to measure air temperature, precipitation, winds, radiation, and soil temperature.
Earth Science > Land Surface > Soils > Soil Temperature
Soil moisture probes are in situ ground-based sensors that measure soil water content. The most common type of soil moisture probes used for scientific research use dielectric permittivity techniques, such as capacitance or time-domain reflectometry sensors. These types of probes measure the charge-storage capacity of the soil to determine the soil moisture content. They typically operate at frequencies around 50 MHz and above to reduce sensitivity to salinity. Soil moisture probes provide continuous measurements and are relatively easy to deploy.
Stream gauges are ground-based sensors that measure the water level or stage of rivers and streams at specific locations. The flow or discharge of a river can then be calculated from these stage measurements. These gauges can provide continuous data, making them useful for monitoring flood risk and water supply. The United States Geological Survey (USGS) operates a network of over 10,000 stream gauges across the United States to assist with flood prediction and water resource management.
Earth Science > Terrestrial Hydrosphere > Surface Water > Surface Water Processes/measurements > Stage Height
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.
Earth Science > Atmosphere > Atmospheric Water Vapor
Earth Science > Atmosphere > Atmospheric Pressure
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Humidity
Earth Science > Atmosphere > Atmospheric Temperature > Surface Temperature > Air Temperature
The Aircraft-Integrated Meteorological Measurement System (AIMMS) is an in situ airborne sensor developed by Aventech Research, Inc. It measures the aircraft's position, altitude, temperature, relative humidity, static pressure, and three-dimensional wind vector. The system includes an Inertial Measurement Unit (IMU), Global Positioning System (GPS), Air Data Probe (ADP), and a central processing module (CPM) for processing the GPS data. AIMMS provides data at a rate of up to 20 Hz and can operate in temperatures ranging from -20 to 50 degrees Celsius.
Earth Science > Atmosphere > Atmospheric Temperature > Upper Air Temperature
Earth Science > Atmosphere > Atmospheric Temperature
LI-COR Gas Analyzer is an in situ gas analyzer manufactured by LI-COR. They can be deployed on aircraft, research vessels, vehicles, balloons, and ground-based platforms. They provide measurements of various trace gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water vapor (H2O). Most models use Optical Feedback-Cavity Enhanced Absorption Spectroscopy (OF-CEAS) to collect measurements. LI-COR gas analyzers have a typical measurement rate of 1 Hz and an operating temperature range of -25 to 45 degrees Celsius.
The Passive-Cavity Aerosol Spectrometer Probe (PCASP) is an in situ airborne optical spectrometer manufactured by Droplet Measurement Technologies. It detects light scattered by particles to determine aerosol size distribution and concentration within the 0.1 to 3.0 μm range. PCASP operates at a wavelength of 632 nm and typically samples at 10 Hz.
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.
Earth Science > Atmosphere > Atmospheric Water Vapor
Earth Science > Atmosphere > Atmospheric Pressure
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Indicators > Humidity
Earth Science > Atmosphere > Atmospheric Temperature > Surface Temperature > Air Temperature
The Cloud Aerosol and Precipitation Spectrometer (CAPS) is an in situ airborne spectrometer manufactured by Droplet Measurement Technologies. It combines 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 50-1600 μm in size, with a time resolution of 1 Hz. It can also capture images of cloud particles and provide measurements of temperature, pressure, and LWC.
Generic-Chemistry Related Sensors (Gen-Chemistry) refers to non-specific instruments on a platform used for atmospheric chemistry measurements. These are typically in situ analyzers that measure various chemical compounds such as trace gases, halocarbons, volatile organic compounds, nitrates, aerosols, and other chemical species. Measurements can include mixing ratio, composition, particle size, optical properties, and particle size distribution.
The Phase Doppler Interferometer (PDI) is an in situ airborne interferometer developed by Artium Technologies, Inc. It is based on light scattering interferometry and laser Doppler velocimetry to measure the size and velocity of spherical cloud particles. It operates at wavelengths of 491, 532, 561, and 660 nm and has a measurement duration of 1 second. PDI can measure droplet sizes from 0.3 to 6000 μm and velocities from -600 to 1000 meters per second
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 Particle Soot Absorption Photometer (PSAP) is an in situ airborne photometer manufactured by Radiance Research. It applies Beer's Law to measure the change in light transmission of aerosol particles. These measurements help determine aerosol absorption and extinction. PSAP operates across three wavelengths (467, 530, and 660 nm) and has a 1-second time resolution. It is usually deployed on aircraft, but it can also be used on ships and vehicles.
Condensation Particle Counters (CPCs) are in situ sensors that measure aerosol particle concentrations. CPCs determine aerosol levels by condensing fluid onto particles, causing them to grow to sizes detectable by optical scattering. Typically, CPCs can detect particles ranging from 7 nm to 3 μm, measure concentrations up to 100,000 particles per cubic centimeter, and provide readings every second. CPCs are manufactured by TSI Incorporated and can be used on airborne, shipborne, and ground-based platforms.
The Tandem Differential Mobility Analyzer (TDMA) is an in situ airborne and ground-based analyzer that measures the physical properties of aerosol particles, such as size distribution and concentration. It can measure particles in the size range of 0.013 to 0.75 mm with a size resolution of 0.013 mm at 0.2 mm. The TDMA is often combined with an Aerodynamic Particle Sizer (APS) to enable measurements of particles in the submicron range. A typical measurement sequence of TDMA takes approximately 45 minutes to complete.
The Forward Scattering Spectrometer Probe (FSSP) is an in situ airborne optical particle counter initially developed by Particle Measuring Systems, Inc. It determines particle size distribution by measuring the light intensity scattered by individual particles within the cloud. FSSP can detect particles ranging from 0.5 to 47 μm in diameter. It functions at a wavelength of 633 nm and typically samples at a rate of 1 Hz.
The Condensation Nuclei Counter (CNC) is an in situ optical sensor produced by Droplet Measurement Technologies. It detects cloud condensation nuclei (CCN) by supersaturating the sampled air, allowing CCN particles to become detectable. The particles are then measured with an optical particle counter (OPC). CNC can detect particles from 0.75 to 10 μm in diameter and operates at a sampling rate of 1 Hz. It is suitable for both airborne and ground-based operations.
