Integrated Precipitation and Hydrology Experiment

The NOAA X-band dual-Polarimetric (NOXP) radar is a ground-based mobile radar developed by the National Severe Storms Laboratory (NSSL). It has been used to provide radar measurements of various weather phenomena such as tornadoes, hurricanes, winter storms, and dust storms. It operates at a 3 cm wavelength allowing it to detect smaller particles such as tiny water droplets and snowflakes. NOXP has a gate spacing of 75 m, a maximum unambiguous range of 88 km, and a volume scan time of 2-3 minutes.

The Two-Dimensional Video Disdrometer (2DVD) is a stationary ground-based optical disdrometer. It is equipped with two line-scan cameras that provide continuous measurements of various precipitation properties such as droplet shape, fall velocity, and size distribution. The 2DVD is capable of accurate measurements for all precipitation particles with a diameter > 0.2 mm, making it well-suited for various precipitation studies.

The Micro Rain Radar (MRR) is a ground-based, vertically pointing, 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 received by the MRR’s antenna can measure precipitation size distributions in the range of 0.25 mm to 4.53 mm, as well as calculate the frequency shift of falling precipitation to be used to calculate its velocity. Additional applications of the MRR include locating bright bands, nowcasting precipitation, and capturing chemical transport during precipitation events.

Rain gauges are ground-based instruments that provide in situ measurements of liquid precipitation amounts over a set time. There are multiple types of rain gauges that each collect and record data differently such as the tipping bucket rain gauge and weighing precipitation gauge. Rain gauges can be deployed in various locations due to their relatively small size and easy set-up and are typically colocated with other precipitation instruments such as disdrometers to provide more details about precipitation being collected such as precipitation rate and size distribution.

Ceilometers are ground-based, remote-sensing sensors that provide measurements of cloud ceilings and vertical visibility. They use either a laser beam or another light source to detect backscatter of clouds, precipitation, and aerosols. Ceilometers can provide detailed and accurate measurements in all types of weather conditions and have low operating costs. Ceilometers are typically used in boundary layer and cloud research applications.

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 derive column-integrated amounts of water vapor and liquid water in the atmosphere. MWR has a field of view (FOV) from about 5.9 to 4.5 degrees depending on the channel and has a typical time resolution of 20 s for sky-view observations.

The Autonomous Parsivel Unit (APU) is an in situ ground-based optical disdrometer. APU measures the size and fall velocity of hydrometeors with a size range of 0-25mm and fall velocities between 0-20 m/s. From 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 has a typical sampling frequency of 10 s.

The Total Sky Imager (TSI) is a ground-based, optical instrument that is manufactured by Yankee Environmental Systems (YES), Inc. TSI can provide full-color, hemispheric images of the sky during the day by using a charge-coupled device (CCD) imager. It also can provide measurements of fractional sky cover and sun obscuration by cloud. TSI can be mounted on mobile platforms such as trailers and research vehicles, allowing it to collect cloud cover measurements in various locations during a field investigation.

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The NASA S-band Dual Polarimetric Radar (NPOL) is a transportable, ground-based scanning dual polarimetric Doppler radar. As an active remote sensor, NPOL detects returned electromagnetic radiation to identify radar reflectivity, Doppler velocity, rainfall rate, particle size distribution, water contents, and precipitation type. Under typical operating conditions, NPOL has a beamwidth of 0.95° and a 150 km maximum range. NPOL is operationally equivalent to Doppler radars employed by the U.S. National Weather Service’s Next Generation Weather Radar (NEXRAD) network, but NPOL has the added advantage of being fully deployable.

The Dual-frequency Dual-polarized Doppler Radar (D3R) is a mobile Ku-/Ka-band radar that was developed for NASA’s Global Precipitation Measurement (GPM) mission Ground Validation (GV) program. D3R is an active remote, ground-based sensor that measures radar backscatter to provide reflectivity, Doppler velocity, differential reflectivity, correlation coefficient, and other radar observations. These measurements can be used to derive droplet size distribution and determine hydrometer type. D3R has a beam width of around 0.9 degrees, a maximum range of 30 km, and a gate spacing of 150 m. D3R operates at similar wavelengths as the Dual-frequency Precipitation Radar (DPR) on the GPM Core satellite and can be used for validation of DPR observations.

The Lightning Instrument Package (LIP) is an in situ airborne electric field detection system. LIP uses eight electric field mills and a conductivity probe to provide measurements of the three-dimensional components of the electric field of surrounding thunderstorms. LIP has a sampling frequency of 0.02 seconds and has an accuracy of 2.5%.

The ER-2 X-Band Doppler Radar (EXRAD) is a dual-beam, X-band radar that operates on NASA’s ER-2 aircraft. It was originally designed to fly on the Global Hawk but instead was developed for ER-2 to replace the ER-2 Doppler Radar (EDOP). EXRAD measures backscatter to determine radar reflectivity, Doppler velocity, and linear depolarization ratio. These measurements can be used to derive details about the phase, orientation, size, and other properties of precipitation particles. EXRAD operates at the 9.6 GHz frequency and has a range resolution of 37.5 to 300 meters. It has a swath width of 28 km at an altitude of 20 km in scanning mode and has a typical sampling frequency of 0.25 seconds.

The High-Altitude Wind and Rain Airborne Profiler (HIWRAP) is an airborne Ka- and Ku-band, dual-beam Doppler radar system. It measures radar reflectivity and 3-D wind fields within clouds and precipitation making it ideal for research missions into hurricanes and severe storms. It was designed to operate at higher altitudes (~ 20 km) than previous airborne wind profilers allowing for a better vertical profile of the troposphere. HIWRAP has a range resolution of 150 m and operates at the following frequencies: 13.5 GHz, 13.9 GHz, 33.7 GHz, and 35.6 GHz.

The Advanced Microwave Precipitation Radiometer (AMPR) is an airborne passive microwave radiometer. AMPR provides calibrated brightness temperature, which can be used to derive cloud and precipitation properties. It operates across four microwave channels: 10.7, 19.35, 37.1, and 85.5 GHz. These frequencies are sensitive to precipitation, thus making AMPR well-suited for rain event studies.

The Cloud Radar System (CRS) is an airborne W-band polarimetric Doppler radar. CRS provides radar observations of clouds and precipitation from the surface up to the lower stratosphere. It has an operating frequency of 94 GHz and has a 150m range resolution. CRS has a typical vertical resolution of 100m and a gate spacing of 37.5m.

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If instrument model information is not available, can use this instrument entry for temperature, pressues, wind speed, wind direction, humidity

The Conical Scanning Millimeter-wave Imaging Radiometer (CoSMIR) is an airborne imaging radiometer that was developed to validate the Special Sensor Microwave Imager/Sounder (SSMIS) instrument. CoSMIR operates across 9 spectral channels in the 50-183 GHz range to measure microwave brightness temperature. CoSMIR has a surface footprint resolution of 1.4 km x 1.4 km at an altitude of 20 km at nadir. It can perform both conical and cross-tracking scanning.

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a miniature, lightweight, low-power cloud particle spectrometer that measures droplets in the range of 2-50 µm in concentrations as high as 2000 particles/cm3

The Cloud Spectrometer and Impactor (CSI) combines the counterflow virtual impactor with a new lightweight cloud droplet probe to allow for detailed studies of total condensed water (TCW), liquid and ice, in clouds. The CSI can measure TCW from ~ 1 mg/m3 to several g/m3 depending on the configuration; in addition particle sizes from 2 to 50 μm are resolved with the droplet probe. The instrumentation can be mounted externally on most aircraft.

Condensation Particle Counters (CPCs) are in situ sensors that measure aerosol particle concentration. CPCs measure aerosol concentration by condensing fluid onto the particles, allowing them to grow to more detectable sizes for optical scattering. Typically, CPCs can detect particles with a size range of 7 nm-3 μm, can measure particle concentrations up to 100,000 particles/cc, and can provide measurements at 1-second intervals. CPCs are manufactured by TSI Incorporated and can be deployed on airborne, shipborne, and ground-based platforms.

If instrument model information is not available, can use this instrument entry for temperature, pressues, wind speed, wind direction, humidity

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The Nevzorov liquid water content (LWC) and total water content (TWC) probe is a constant-temperature, hot-wire probe designed for aircraft measurements of the ice and liquid water content of clouds. The probe consists of two separate sensors for measurements of cloud liquid and total (ice plus liquid) water content. Each sensor consists of a collector and a reference winding. The reference sensors are shielded from impact with cloud particles, specifically to provide an automatic compensation for convective heat losses.

The Rosemount Icing Detector (RICE) is an in situ airborne probe manufactured by Rosemount Inc. It is a magnetostrictive oscillation probe that detects changes in the frequency of oscillation due to ice buildup on the sensing cylinder. These changes in frequency can be related to the rate of ice accretion, which can be used to derive liquid water content. RICE has a typical sampling rate of 1 second.

A TUNABLE DIODE LASER is a solid-state laser in which as lasing is achieved by passing an injection current through the active region of a semiconductor across the p-n junction; tunable meaning it is used with a technique based upon the measurement of light absorption upon irrigating a sample using a tunable laser source.

The High Volume Precipitation Spectrometer 3 (HVPS-3) is an in situ airborne particle imager manufactured by SPEC Inc. It uses a 128-photodiode array to provide imagery of precipitation particles. The imagery can be used to determine the shape, size, and concentration of the particles. HVPS-3 has a pixel resolution of 150 μm and a maximum field of view of 1.92 cm.

The 2D-C/P Hydrometeor Imaging Probe (2D-C/P) is an in situ, airborne instrument that captures imagery of hydrometeors. It collects these images by recording the status (illuminated or shadowed) of the photodiode array as the shadow of the hydrometeors passes over. 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.

The Cloud Particle Imager (CPI) is an airborne imager manufactured by SPEC Inc. CPI collects high-resolution (2.3 μm pixel size) images of cloud particles that pass through its sample volume. It uses a charge-coupled device (CCD) camera that operates at 810 nm to record images and can take up to 74 frames per second with a refresh rate of 40 Hz. The imagery from CPI can be used to derive microphysical properties such as particle size and habit.

The King Probe is an airborne cloud probe 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 provides measurements of cloud liquid water content (LWC) by measuring the heat released when water droplets are vaporized. The King Probe operates at a constant temperature (~100 C) and has a data output rate of 1 to 10 Hz. It is typically used in cloud microphysics and aircraft icing studies.

The Cloud Imaging Probe (CIP) is an in situ airborne optical array probe manufactured by Droplet Measurement Technologies. CIP records cloud particle images by capturing the shadow of the particles as they pass through the laser. It also provides information on the particle size distribution and cloud liquid water content. CIP has a typical resolution of 25 μm and can measure particles in the size range of 12.5 μm - 1.55 mm.

The 2D-Stereo Particle Probe (2D-S) is an in situ airborne optical imaging probe developed by SPEC Inc. The 2D-S uses two diode laser beams to produce stereo cloud particle images through linear array shadowing. Through the imagery, cloud particle size distribution, particle number concentration, and ice/liquid water content can be determined. It has a resolution of 10 µm and can measure hydrometeors in the 25-1280 µm range.

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The Next Generation Weather Radar (NEXRAD) is a network of high-resolution, S-band radars operated by the National Weather Service (NWS), the Federal Aviation Administration (FAA), and the United States Air Force. NEXRAD measures the magnitude of the returned energy to provide reflectivity, velocity, and spectrum width observations, which can be processed to create mosaic maps of precipitation. NEXRAD radars typically operate with a 0.9 degree beamwidth, 0.25-1 km spatial resolution, and 230-460 km maximum range. There are currently over 160 NEXRAD radars operating in the United States and select overseas locations.