The Light Precipitation Evaluation Experiment (LPVEx) was a NASA-led campaign focused on better understanding light precipitation events and validating retrievals for current and upcoming satellite missions. Most LPVEx operations took place in and around the Gulf of Finland from September to October 2010, although ground instruments continued to be used into late December. LPVEx used the University of Washington’s King Air aircraft, Finland’s Aranda research vessel, and various models and satellites to collect data on light precipitation microphysics, how these events form, and rainfall estimates. LPVEx also supported NASA’s Global Precipitation Mission (GPM).
Conductivity, Temperature, and Depth (CTD) sensors are in situ instruments used to measure water depth, pressure, salinity, temperature, and density in the ocean. CTD sensors can be deployed on various water-based platforms such as autonomous underwater vehicles (AUVs), buoys, gliders, or research vessels. When mounted on a vessel, CTD sensors are usually attached to a rosette and then lowered to the seafloor to record water properties. These sensors typically sample at 30 Hz and can provide accurate measurements at specific water depths according to the researcher's needs.
Earth Science > Oceans > Ocean Pressure > Water Pressure
Earth Science > Oceans > Bathymetry/seafloor Topography > Water Depth
Earth Science > Oceans > Ocean Temperature > Water Temperature
Earth Science > Oceans > Salinity/density
The Acoustic Doppler Current Profiler (ADCP) is an in situ acoustic sensor used to measure ocean currents. ADCP utilizes the Doppler effect to detect sound waves, providing measurements of the speed and direction of currents throughout the water column. It can be easily mounted on various water platforms such as ships, buoys, and autonomous underwater vehicles (AUVs). Additionally, it can be deployed on the seafloor to deliver profile measurements of ocean currents.
The Micro Rain Radar (MRR) is a ground-based, vertically oriented, continuous wave K-band (24.23 GHz) radar that measures various parameters of precipitation, such as liquid water content and rain rate, from near ground level to the lower troposphere. The backscatter captured by the MRR’s antenna can determine precipitation size distributions ranging from 0.25 mm to 4.53 mm and can also calculate the frequency shift of falling precipitation to determine its velocity. Additional uses of the MRR include identifying bright bands, nowcasting precipitation, and tracking chemical transport during precipitation events. It has a range resolution of 10 to 200 meters and a sampling time of 10 seconds.
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 Optical Disdrometer (ODM), manufactured by Eigenbrodt, is an in-situ optical sensor that measures precipitation occurrence, intensity, and accumulation for rain, snow, and mixed-phase precipitation using minute-based particle size distributions. It is designed for shipboard use in high and variable wind conditions. ODM uses an infrared (880 nm) light-emitting diode to illuminate the measuring volume and can detect hydrometeors ranging from 0.1 to 22 mm in size, classifying them into 128 size bins. It operates fully automatically and requires minimal maintenance.
Photosynthetically Active Radiation (PAR) Sensors are in situ optical devices used to study photosynthesis and plant physiology. They detect light between 400 and 700 nm and convert it into signals for PAR measurement. PAR sensors can be mounted on ground-based or water-based platforms or be portable and handheld. They are primarily used in agriculture, such as monitoring crop growth and analyzing light distribution in plant canopies, but they are also employed to study phytoplankton and aquatic productivity.
Earth Science > Biosphere > Vegetation > Photosynthetically Active Radiation
The Station for Measuring Ecosystem-Atmosphere Relations (SMEAR) is a network of research stations across northern Europe run by the University of Helsinki. Each station has various in situ instruments mounted on flux towers to collect data on temperature, humidity, wind direction and speed, radiation, and aerosols. Measurements are taken daily with a typical sampling frequency of 1 minute.
Earth Science > Agriculture > Soils > Soil Temperature
Earth Science > Biosphere > Vegetation > Photosynthetically Active Radiation
TSI Particle Probes are in situ particle counters and detectors manufactured by TSI Incorporated. They are used to detect aerosol particles and determine concentration and particle counts. TSI Particle Probes are typically combined with particle sizers, which can measure size distribution. TSI Particle Probes can be deployed on aircraft, research vessels, and ground-based platforms.
C-band radars operate within the 4-8 GHz frequency range. They provide measurements of radar reflectivity, Doppler velocity, and other parameters to characterize precipitation and clouds. C-band radars are usually used for short-range weather observations because they are more prone to attenuation.
Rain gauges are ground-based instruments that measure liquid precipitation amounts directly over a specified period. Different rain gauges, such as tipping buckets and weighing gauges, collect and record data in various ways. Because of their small size and easy setup, rain gauges can be placed in different locations and are often used alongside other precipitation instruments like disdrometers to gather more details, such as precipitation rate and size distribution.
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
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.
Earth Science > Atmosphere > Atmospheric Radiation > Solar Irradiance
Earth Science > Atmosphere > Atmospheric Radiation > Solar Radiation
A pyrgeometer is a ground-based or airborne passive radiation sensor. It measures downward and upward longwave radiation in the 4-50 μm spectral range. Pyrgeometers measure changes in resistance/voltage using a thermopile sensor to determine longwave radiation. These measurements can be used to calculate the infrared radiation flux. Pyrgeometers are typically used for climatological, meteorological, and agricultural applications.
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.
The ADvanced MIcrowave RAdiometer for Rain Identification (ADMIRARI) is an airborne passive microwave radiometer. ADMIRARI measures brightness temperatures at 10.7, 21.0, and 36.5 GHz frequencies along two polarized planes. It is also equipped with a Micro Rain Radar (MRR) to observe rain structure and a cloud lidar to estimate cloud base. ADMIRARI's measurements can be used to determine rain/cloud liquid water path (LWP) and integrated water vapor (IWV). It has a temporal resolution of 1 second and a spatial resolution of 5 degrees.
Earth Science > Spectral/engineering > Microwave > Brightness Temperature
The Two-Dimensional Video Disdrometer (2DVD) is a stationary, ground-based optical disdrometer. It has two line-scan cameras that continuously measure various precipitation properties such as droplet shape, fall velocity, and size distribution. The 2DVD precisely measures all precipitation particles larger than 0.2 mm in diameter, making it suitable for various precipitation studies.
The Autonomous Parsivel Unit (APU) is an in situ ground-based optical disdrometer. APU measures the size and fall velocity of hydrometeors with a range of 0-25 mm in size and 0-20 m/s in fall speed. Using these measurements, the drop size distribution, type, intensity, and amount of precipitation can be determined. APU operates in the 650-780 nm wavelength range and typically samples every 10 seconds.
The Ultra-High Frequency (UHF) Wind Profiler is a ground-based Doppler radar. It measures electromagnetic signals to detect wind speed and direction. UHF Wind Profilers operate at the 300-1000 MHz frequency range. Due to operating at a high frequency, they allow for high-resolution wind measurements within the boundary layer.
The Joss-Waldvogel (JW) Disdrometer is a ground-based impact-type disdrometer manufactured by Distromet. It uses an electromechanical counter to determine the drop size distribution (DSD) of raindrops. It can detect raindrops within the 0.3 to 5.5 mm diameter size range. The JW Disdrometer can record up to 200 drops per second and has a typical sampling frequency of 1 minute.
A Snow Water Equivalent (SWE) Sampler is a ground-based device used in the field to measure SWE. A core sample of snow is collected using a snow tube sampler or snow corer. The tube is inserted vertically into the snowpack until it reaches the ground surface, and a ruler on the tube measures the snow depth. The sample is then removed and weighed on a calibrated scale to determine the snow density. The SWE within the sample is calculated by multiplying the snow density by the snow depth.
The Precipitation Occurrence Sensor System (POSS) is a ground-based X-band, continuous wave Doppler radar designed by the Meteorological Service of Canada. It measures the Doppler signals of particles to determine precipitation occurrence, type, and rate. POSS operates at the 10.525 GHz frequency and has a spectral resolution of 16 Hz. It measures the falling particles through a small measurement volume extending to about 2 meters above the sensor. POSS provides 1-minute-averaged measurements and has a sampling frequency of 2.048 kHz.
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 Micro Rain Radar (MRR) is a ground-based, vertically oriented, continuous wave K-band (24.23 GHz) radar that measures various parameters of precipitation, such as liquid water content and rain rate, from near ground level to the lower troposphere. The backscatter captured by the MRR’s antenna can determine precipitation size distributions ranging from 0.25 mm to 4.53 mm and can also calculate the frequency shift of falling precipitation to determine its velocity. Additional uses of the MRR include identifying bright bands, nowcasting precipitation, and tracking chemical transport during precipitation events. It has a range resolution of 10 to 200 meters and a sampling time of 10 seconds.
Pluvio is a ground-based weighing precipitation gauge manufactured by OTT HydroMet. It measures precipitation amount and rate by determining its weight using a high-capacity collection bucket. Pluvio can measure rain, snow, sleet, hail, and mixed precipitation types. It has a standard sampling interval of 1 minute and an accuracy of ± 0.05 to 0.1 mm.
The Snowflake Video Imager (SVI) is a ground-based imaging system developed at Wallops Flight Facility (WFF). It records greyscale imagery of snowflakes to determine snowflake size and orientation distribution. It can operate autonomously in harsh winter conditions with winds up to 50 knots and temperatures as low as -40 degrees Celsius. SVI has a high frame rate of 60 Hz and a nominal pixel size of 0.05 mm by 0.1 mm.
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.
The Nezorov 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 caused by 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 Cloud Imaging Probe (CIP) is an in situ airborne optical array probe manufactured by Droplet Measurement Technologies. It captures cloud particle images by recording shadows as particles pass through a laser. Additionally, it provides data on particle size distribution and cloud liquid water content. CIP typically has a resolution of 25 μm and can measure particles ranging from 12.5 μm to 1.55 mm.
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). The King Probe measures cloud liquid water content (LWC) by detecting the heat released when water droplets vaporize. It operates at a constant temperature of approximately 100°C and has a data output rate of 1 to 10 Hz. The probe is commonly used in studies of cloud microphysics and aircraft icing.
W-band radars are highly sensitive radars used for atmospheric research. They operate around the 94-95 GHz frequency band, allowing for the detection of small water droplets. W-band radars are used for cloud and precipitation studies since they can provide more detailed observations than typical weather radars. They can be deployed on research vessels, aircraft, and mobile ground-based platforms.
The Cloud Droplet Probe (CDP) is an in situ cloud probe manufactured by Droplet Measurement Technologies. It measures the particle size distribution and concentration for cloud particles in the 2-50 μm size range. CDP detects pulses of light scattered from a laser (658 nm) to count and size individual cloud droplets. CDP has a typical measurement rate of 1 Hz and can detect concentrations of up to 2000 particles per cubic centimeter.
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 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 shadow of the hydrometeors passes over. 2D-C/P also offers 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.
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.
The Rosemount Icing Detector (RICE) is an in-situ airborne probe developed by Rosemount Inc. It uses magnetostrictive oscillation to detect shifts in frequency caused by ice accumulation on the sensing cylinder. These frequency changes correlate with the rate of ice buildup, which helps determine liquid water content. RICE typically samples every second.
The Particule 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 proportional to the droplets' density and particle surface area density. PVM-100A operates at 780 nm and has a measurement rate of up to 5000 Hz. It can measure droplets in the size range of 3-50 μm diameter. The ground-based model of this instrument is PVM-100.
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.
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 2D-Stereo Particle Probe (2D-S) is an in situ airborne optical imaging device developed by SPEC Inc. It uses two diode laser beams to create stereo images of cloud particles via linear array shadowing. These images allow for the determination of cloud particle size distribution, particle number concentration, and ice or liquid water content. 2D-S has a resolution of 10 µm and can measure hydrometeors ranging from 25 to 1280 µm.
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.
Radiosondes are a balloon-borne instrument package used to collect profile measurements of pressure, temperature, humidity, and winds. These sensors are connected to a radio transmitter that sends the measurements to a ground receiver typically operating in the 400-406 MHz range. They typically provide measurements at 1-6 seconds, depending on the type and manufacturer of the radiosonde. Radiosondes are used for weather forecasting, ground truth satellite data, atmospheric research, and input for weather prediction models.
Earth Science > Atmosphere > Atmospheric Water Vapor > Water Vapor Profiles
