Atlantis
R/V Atlantis

Chilled Mirror Hygrometers (CMHs) are in situ sensors that directly measure dew point temperature by condensing water vapor onto a chilled mirror surface. The mirror's temperature is lowered with thermoelectric coolers until water vapor from the sample gas condenses as dew or frost. The mirror's temperature is then measured with a platinum resistance thermometer (PRT) to determine the dew point and humidity. CMHs have been used on both airborne and ground-based platforms and serve as the NIST-traceable reference standard for calibrating other sensors.

Sound Detection and Ranging (SODAR) is an active, ground-based acoustic sensor that measures atmospheric winds and turbulence. It emits acoustic energy into the atmosphere and detects the strength and frequency of the backscattered signal. The backscattered signal can be used to determine the horizontal wind field, assuming the scattered energy moves with the mean wind. SODARs are frequently used in boundary layer studies to measure turbulence and wind profiles.

Sunphotometers are passive optical sensors that measure the amount of sunlight. They are pointed directly at the sun to measure direct sunlight, not sunlight scattered by aerosols. These measurements can be used to determine aerosol optical depth by applying Beer’s Law. Sunphotometers have been deployed on aircraft, research vessels, and field sites for aerosol research and monitoring.

The NOAA Chemical Ionization Mass Spectrometer (NOAA-CIMS) is an in situ airborne spectrometer developed by NOAA. It was designed to provide high-precision measurements of reactive nitrogen and halogen species, including nitric acid, nitric oxide, and bromine chloride, in the upper atmosphere. It can also measure ozone and water vapor concentrations. NOAA-CIMS has a detection limit of 30 pptv and a temporal resolution of 1 second.

The Quantum Cascade Laser System (QCLS) is an airborne and ground-based in situ spectrometer developed by Harvard University and Aerodyne Research. QCLS comprises two instruments: the Harvard QCL DUAL and the Harvard QCL CO2. The QCL DUAL uses two thermoelectrically cooled QCL light sources to measure carbon monoxide (CO) at 4.59 microns and methane (CH4) and nitrous oxide (N2O) at 7.87 microns. The QCL CO2 instrument employs a single QCL light source to measure carbon dioxide (CO2) at 4.32 microns. QCLS operates at a measurement frequency of 1 Hz.

C-band radars operate in 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 typically used for short-range weather observations because they are more prone to attenuation.

The Ultra-High Frequency (UHF) Wind Profiler is a ground-based Doppler radar that measures electromagnetic signals to determine wind speed and direction. UHF Wind Profilers operate in the 300-1000 MHz frequency range. Because of their high operating frequency, they provide high-resolution wind measurements within the boundary layer.

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.

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 chemical compounds such as trace gases, halocarbons, volatile organic compounds, nitrates, aerosols, and other chemical species. Measurements can include mixing ratios, composition, particle size, optical properties, and particle size distribution.

The Proton Transfer Mass Spectrometer (PTR-MS) is an in situ spectrometer developed by the University of Innsbruck in Austria and used both on aircraft and on the ground. It detects volatile organic compounds (VOCs) without sample preparation at very low concentrations. PTR-MS employs chemical ionization mass spectrometry, enabling rapid, highly sensitive VOC detection. It has a signal integration time of 0.5 to 1 second.

Eddy Covariance Flux Towers are in situ micrometeorological surface towers. They are equipped with gas sensors to continuously measure trace gas fluxes between the land surface and the atmosphere. Eddy Covariance Towers are typically used to measure fluxes of carbon dioxide (CO2), methane (CH4), and water vapor (H2O). These towers are also equipped with various meteorological sensors to measure air temperature, precipitation, wind, radiation, and soil temperature.

Generic-Radiometers refer to non-specific radiometers on a platform. These are typically passive microwave radiometers that measure brightness temperature. Radiometers can be used to retrieve temperature and water vapor profiles, soil moisture content, ocean salinity, precipitation and cloud properties, and vegetation.

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 Scanning Mobility Particle Sizer (SMPS) is an in situ aerosol sensor manufactured by TSI Incorporated. The SMPS uses a differential mobility analyzer (DMA) to measure the electrical mobility diameter of aerosol particles, thereby determining the size distribution. It also counts aerosol particles using a condensation particle counter (CPC). It detects particles in the 10-1000 nm size range and typically completes each scan in about 10 seconds. The SMPS can be used on airborne or ground-based platforms.

The Single Particle Soot Photometer (SP2) is an in situ laser-induced photometer developed by Droplet Measurement Technologies. SP2 measures the black carbon (BC) mass in individual aerosol particles and their optical and physical properties. The device detects aerosol particles with diameters of 200-400 nm and can analyze up to 25,000 particles per second. It operates at a sampling rate of 1 Hz and uses a wavelength of 1.06 μm. It can be used on airborne or ground-based platforms and paired with a Humidified-Dual SP2 (HD-SP2).

The Picarro gas concentration analyzer is an in situ airborne or ground-based sensor manufactured by Picarro, Inc. It uses Wavelength-Scanned Cavity Ring Spectroscopy (WS-CRDS) to measure trace gases such as carbon dioxide, carbon monoxide, methane, and water vapor. For carbon dioxide measurements, the laser operates at 1603 nm, while 1651 nm is used for methane and water vapor measurements. Picarro has a typical sampling time of 2.5 seconds. Depending on the model, Picarro can also provide measurements of carbon isotopes for gas concentrations.

NOx/NOxy is an in situ chemiluminescence instrument that measures nitrogen oxides and ozone in the atmosphere. It provides spatial resolution better than 100 meters at typical DC-8 research flight speeds. NOx/NOxy can be deployed on ground-based, airborne, and shipborne platforms, supporting a range of atmospheric chemistry and air quality studies.

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.

The Aerodynamic Particle Sizer (APS) is an in situ spectrometer manufactured by TSI Instruments. It measures aerodynamic particles in the 0.5-20 μm size range and light-scattering intensity in the 0.37-20 μm optical size range. The 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. The APS can be deployed on aircraft, ships, or ground-based platforms.

The Condensation Nuclei Counter (CNC) is an in situ optical sensor produced by Droplet Measurement Technologies and TSI, Inc. It detects cloud condensation nuclei (CCN) by supersaturating the sampled air, making CCN particles detectable. The particles are then measured by an optical particle counter (OPC). The CNC detects 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.

The Fourier Transform Spectrometer (FTS) is a high-resolution spectrometer used in both airborne and ground-based applications. FTS measures the solar radiance reflected from the surface, which can be used to estimate atmospheric concentrations of carbon monoxide (CO), carbon dioxide (CO2), and methane (CH4). It offers a spatial resolution of approximately 100m by 1000m and operates at a measurement frequency of 1 Hz during typical research flights.

The High-Performance Liquid Chromatograph (HPLC) is an in situ ground-based analyzer that separates and identifies components in a sample of air or a mixture. It works by injecting a liquid into the sample, causing different flow rates for each component as they pass through the column. As each component exits the column, its concentration is measured at high resolution. In Earth science research, HPLC is commonly used to detect various trace species in the atmosphere, such as formaldehyde, hydrogen peroxide, and volatile organic compounds (VOCs). Although primarily used for laboratory analysis and ground-based measurements, it can also be employed for airborne measurements.

The Tandem Differential Mobility Analyzer (TDMA) is an in situ airborne and ground-based analyzer that measures aerosol particle properties, including size distribution and concentration. It measures 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 submicron particles. A typical TDMA measurement sequence takes approximately 45 minutes to complete.

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

The Particle Soot Absorption Photometer (PSAP) is an in situ airborne photometer manufactured by Radiance Research. It applies Beer's Law to measure changes in light transmission caused by aerosol particles. These measurements help determine aerosol absorption and extinction. The PSAP operates at three wavelengths (467, 530, and 660 nm) and has a 1-second time resolution. It is typically deployed on aircraft but can also be used on ships and vehicles.

Thermo Scientific Gas Analyzers are in situ gas analyzers manufactured by ThermoFisher Scientific. They provide precise measurements of trace gases, including ozone, carbon dioxide, carbon monoxide, and sulfur dioxide. Thermo Scientific Gas Analyzers can be deployed on aircraft, research vessels, and ground-based platforms.

Ceilometers are ground-based remote-sensing instruments that measure cloud ceilings and vertical visibility. They use a laser or another light source to detect backscatter from clouds, precipitation, and aerosols. Ceilometers provide detailed, precise measurements in all weather conditions and are cost-effective to operate. They are commonly used in boundary-layer and cloud research.

The Aerosol Mass Spectrometer (AMS) is an in situ spectrometer developed by Aerodyne Research. It uses quadrupole mass spectrometry to measure aerosol chemical composition and properties. It detects particles from 40 nm to 1 micron in size and offers a time resolution of up to 10 Hz. It can be installed on aircraft, research vessels, mobile laboratories, or other ground-based platforms.