NASA African Monsoon Multidisciplinary Analyses

A dropsondes or dropwindsondes are in situ instruments designed to be released from aircraft. They are equipped with Global Positioning System (GPS) receivers and sensors to collect profile measurements of pressure, temperature, humidity, wind speed, and direction. Dropsondes are important during field investigations because they allow researchers to collect vertical profiles in remote locations and during severe weather events. Dropsondes typically have a vertical resolution of 5 m and provide measurements of wind speed/direction every 0.25 seconds and temperature, pressure, and humidity every 0.5 seconds.

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.

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The Carbon monOxide by Attenuated Laser Transmission (COBALT) is an in situ airborne spectrometer manufactured by Los Gatos Research. It uses off-axis integrated cavity output spectroscopy (OA-ICOS) to measure carbon monoxide in the troposphere and tropopause. COBALT operates at 4.60 μm wavelength and has a typical sampling frequency of 1 Hz. COBALT provides measurements at a precision of 0.2 ppbv and does not require regular calibration.

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 Optical Particle Counter is an instrument based on the principle of light scattering from particles. It is a real time instrument that is typically used to measure particles above 0.05 μm in diameter.

The Precipitation and Imaging Probe (PIP) is an airborne optical spectrometer manufactured by Droplet Measurement Technologies. It measures the size and shape of particles in the size range of 100-6200 μm. It provides 2-dimensional imagery with a pixel resolution of 100 μm. PIP operates at the 660 nm wavelength and has a typical sampling frequency of 1 second. It has a sample area of 260 mm x 6.2 mm and can operate at airspeeds of 10-200 meters per second.

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 one instrument. CAPS measures the size distribution of aerosol, cloud, and liquid droplets for particles between the sizes of 50-1600 μm at a time resolution of 1 Hz. It can also record images of cloud particles and provide measurements of temperature, pressure, and LWC.

A Tunable Diode Laser Absorption Spectrometer (TDLAS) is an airborne or ground-based in situ optical spectrometer. TDLAS measures the wavelength-dependent absorption of light to determine the concentration of various trace gases. It can also determine the gas species' temperature, pressure, velocity, and mass flux when possible. TDLAS has a typical time resolution of 1 second.

The Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) is an in situ spectrometer manufactured by Droplet Measurement Technologies. It can be utilized on both airborne and ground-based platforms to measure aerosol size distribution and concentration. UHSAS determines the particle size by detecting the peak light signals of the aerosol particles which are illuminated by a 1054 nm laser. UHSAS can sample particles within the 60 - 1000 nm size range and has a sampling frequency of 10 Hz.

The Aerodynamic Particle Sizer (APS) is an in situ spectrometer manufactured by TSI Instruments. APS measures aerodynamic particles in the 0.5-20 μm size range. It also measures the light-scattering intensity of the particles in the 0.37-20 μm optical size range. APS provides particle size distributions for 52 channels at a typical sampling time of 1 second. It uses a laser diode operating at 655 nm and has a size resolution of 0.02 μm at 1 μm. APS can be deployed on aircraft, ships, or ground-based platforms.

The Condensation Nuclei Counter (CNC) is optical method for counting atmospheric aerosol particles.

A dropsondes or dropwindsondes are in situ instruments designed to be released from aircraft. They are equipped with Global Positioning System (GPS) receivers and sensors to collect profile measurements of pressure, temperature, humidity, wind speed, and direction. Dropsondes are important during field investigations because they allow researchers to collect vertical profiles in remote locations and during severe weather events. Dropsondes typically have a vertical resolution of 5 m and provide measurements of wind speed/direction every 0.25 seconds and temperature, pressure, and humidity every 0.5 seconds.

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 Diode Laser Hygrometer (DLH) is an in situ airborne hygrometer developed by NASA’s Langley Research Center (LaRC). It uses tunable diode laser absorption to measure water vapor in the atmosphere. DLH operates in the near-infrared region at around 1.4 μm and has a measurement frequency of 100 Hz. It can provide accurate measurements of water vapor even while flying through clouds.

The High Altitude Monolithic Microwave integrated Circuit (MMIC) Sounding Radiometer (HAMSR) is an airborne microwave sounder developed by the Jet Propulsion Laboratory under the NASA Instrument Incubator Program. HAMSR measures brightness temperature which can be used to derive three-dimensional profiles of temperature, water vapor, and cloud liquid water in the atmosphere. It operates across 25 spectral channels in 3 microwave bands (50-60 GHz, 118 GHz, 183 GHz) and has a sampling frequency of 5 seconds. HAMSR has a horizontal spatial resolution of 2 km at nadir and a field of view of about 40 km at an altitude of 20 km.

The Langley Aerosol Research Group Experiment (LARGE) is an in situ airborne instrument suite that measures aerosol and cloud microphysical and optical properties such as size distribution, number concentration, and scattering and absorption coefficient. LARGE consists of multiple instruments including the Ultra-High Sensitivity Aerosol Spectrometer (UHSAS), Particle-Into-Liquid Sampler (PILS), Particle Soot Absorption Photometer (PSAP), Cloud and Aerosol Spectrometer (CAS), Cloud Imaging Probe (CIP), and additional cloud and aerosol sensors. The LARGE instruments operate across the 450-700 nm wavelength range, can detect particles in the size range between 0.003-20μm, and have a measurement frequency of 1 Hz. It is typically used for airborne measurements, but it also can be deployed on ground-based platforms such as vehicles.

The Airborne Second Generation Precipitation Radar (APR-2) is a cross-track scanning, dual-frequency airborne precipitation radar. It measures radar backscatter from rainfall to provide measurements of reflectivity, Doppler velocity, and linear depolarization ratio (LDR). APR-2 operates at 13.4 GHz and 35.6 GHz and has a pulse repetition frequency (PRF) of 5000 Hz. At a flight altitude of 11,000 feet, it has a horizontal resolution of 730 m at 13.4 GHz and 920 m at 35.6 GHz. APR-2 has a vertical resolution of 60 m and a ground swath width of 10 km.

The Lidar Atmospheric Sensing Experiment (LASE) is an airborne lidar system developed at NASA Langley Research Center (LaRC). LASE uses the differential absorption lidar technique to provide profile measurements of water vapor and aerosols in the atmosphere. LASE operates at the 815 nm wavelength and has a measurement frequency of 5 Hz. For aerosol scattering profiles, LASE has a horizontal resolution of 200m and a vertical resolution of 30m. It has a horizontal resolution of 5 km and a vertical resolution of 0.2 km for water vapor measurements.

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.

The Meteorological Measurement System (MMS) is an in situ airborne instrument used for measuring atmospheric state parameters. MMS provides high-resolution and accurate measurements of atmospheric pressure, temperature, and wind direction/speed immediately around the plane. Additional parameters can be derived such as potential temperature, true airspeed, turbulence dissipation rate, and Reynolds number. Measurements of all parameters are typically collected at a rate of 20 Hz.

Nephelometers are in situ airborne or ground-based optical sensors. They measure the total scattering and backscattering of aerosol particles in the atmosphere. Nephelometers operate across three wavelengths: 450 nm, 550 nm, and 700 nm, and have a typical time resolution of 1 Hz.

FLUXNET is a global network of eddy covariance flux towers. Each tower is equipped with gas sensors to continuously measure the fluxes of trace gases such as carbon dioxide, methane, and water vapor between the land surface and the atmosphere. These towers are also equipped with various meteorological sensors to measure air temperature, precipitation, winds, radiation, and soil temperature. Currently, FLUXNET has over 250 flux tower sites across the globe in various vegetation types such as tundra, tropical, forest, and grasslands.

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The ZEUS Long-Range Lightning Detection Network is a ground-based network of ZEUS lightning detection systems across Europe, Africa, and Brazil. ZEUS detects the sferics emitted by a cloud-to-ground lightning strike in the very low frequency (VLF) spectrum (7-15 kHz). The lightning location and time are determined by using the arrival time difference (ATD) technique. ZEUS can measure 70 sferics per second and has a spatial accuracy of 10-20 km within the network periphery.

This data will be added in future versions

This data will be added in future versions

This data will be added in future versions.

The Sferics Timing and Ranging Network (STARNET) is a long-range lightning detection network across South America and the Atlantic Ocean. It uses Very Low Frequency (VLF) receivers to measure sferics from lightning strikes. It operates at 7-15 kHz and measures 130 sferics per second. STARNET has a location accuracy of 2 to 10 km in South America and around 20 km in the Atlantic Ocean.

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.