Studies of the Earth’s atmosphere require a comprehensive set ofobservations that rely on instruments flown on spacecraft, aircraft, andballoons as well as those deployed on the surface. Within NASA’sGoddard Space Flight Center (GSFC) Earth Sciences Division-Atmospheres, laboratories and offices maintain an active program ofinstrument system development and observational studies thatprovide: 1) information leading to a basic understanding of atmospheric processes and their relationships with the Earth’s climate system, 2) prototypes for future flight instruments, 3) instruments to serveas calibration references for satellite missions, and 4) instruments forfuture field validation campaigns that support ongoing space missions.Our scientists participate in all aspects of instrument activity, includingcomponent and system design, calibration techniques, retrieval algorithmdevelopment, and data processing systems. The Atmospheres Programhas well-equipped labs and test equipment to support the developmentand testing of instrument systems, such as a radiometric calibration anddevelopment facility to support the calibration of ultraviolet and visible(UV/VIS), space-borne solar backscatter instruments.

This document summarizes the features and characteristics of 46instrument systems that currently exist or are under development. Thereport is organized according to active, passive, or in situ remotesensing across the electromagnetic spectrum. Most of the systems areconsidered operational in that they have demonstrated performance inthe field and are capable of being deployed on relatively short notice. Other systems are under study or of low technical readiness level (TRL). The systems described herein are designed mainly for surface or airborne platforms. However,two Cubesat systems also have been developed through collaborative efforts. The Solar Disk Sextant (SDS) is the singleballoon-borne instrument.

The lidar systems described herein are designed to retrieve clouds, aerosols, methane, water vapor pressure, temperature, and winds. Most of the lasers operate at some wavelength combination of 355, 532, and 1064 nm. Thevarious systems provide high sensitivity measurements based on returns from backscatter or Raman scattering includingintensity and polarization. Measurements of the frequency (Doppler) shift of light scattered from various atmosphericconstitutes can also be made.

Microwave sensors consist of both active (radar) and passive (radiometer) systems. These systems are important for studying processes involving water in various forms. The dielectric properties of water affect microwave brightness temperatures, which are used to retrieve atmospheric parameters such as rainfall rate and other key elements of thehydrological cycle. Atmosphere radar systems operate in the range from 9.6 GHz to 94 GHz and have measurementaccuracies from -5 to 1 dBZ; radiometers operate in the 50 GHz to 874 GHz range with accuracies from 0.5 to 1 degreeK; conical and cross-track scan modes are used.

Our passive optical sensors, consisting of radiometers and spectrometers, collectively operate from the UV into the infrared. These systems measure energy fluxes and atmospheric parameters such as trace gases, aerosols, cloud properties, or altitude profiles of various species. Imager spatial resolution varies from 37 m to 400 m depending onaltitude; spectral resolution is as small as 0.5 nm.

Many of the airborne systems have been developed to fly on multiple aircraft.

In situ systems provide a wide range of unique observing capabilities that are used to validate satellites measurements and tobetter understand the interaction among atmospheric variables through direct observations. These observing systemsconsist of both ground and airborne sensors. Measurements are made with instruments such as rain gauges,disdrometers, gas analyzers, and laser-based detectors. A complete mobile facility (COMMIT), housed in a 20-foot trailer,has traveled widely over the globe to support numerous field and validation campaigns.

Instrument systems evolve and change over time, and therefore this report has been updated as required, typically everythree to five years. The previous report was completed in 2011; 18 new instruments programs have begun since thattime and are included in this 2017 report. An electronic version of this report is posted on the Earth Sciences Division-Atmospheres Website at: http://earth.gsfc.nasa.gov/.

We want to thank all of the Laboratory members who contributed material on the various instrument systems, and especially the efforts of Chuck Cote (SSAI) and Omega Williams (610) who managed and coordinated the report preparation as well as Judith Clark (TIMS) for formatting, proofreading, and editing support.

Sincerely,

Steven Platnick Karen Mohr

Deputy Director for Atmospheres Associate Deputy Director for Atmospheres

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