NASA Laboratory for Atmospheres 2011 Instrument Systems Report

Studies of the atmosphere require a comprehensive set of observations, relying on instruments flown on spacecraft, aircraft, and balloons, as well as those deployed on the surface. The Laboratory of Atmospheres has an active program of instrument systems development that provides: 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 serve as calibration references for satellite mission planning and 4) instruments for future field validation campaigns that support ongoing space missions. Laboratory scientists participate in the design of the instruments, data processing algorithms, calibration techniques, and the data processing systems. The Laboratory has well-equipped labs and test equipment to support the development and testing of instrument systems. For example, a radiometric calibration and development facility exists that supports the calibration for ultraviolet and visible (UV/VIS) space-borne solar backscatter instruments. A class 10,000 clean room is maintained.

The features and characteristics of 36 instrument systems that currently exist or are under development are summarized in this document. The report is organized into five sections: Lidar, Passive Optical, Microwave, In-Situ, and Research and Development. The first four sections summarize existing systems that are considered operational in that they are performing measurements in the laboratory or have operated in the field and are capable of being deployed on short notice. The fifth section describes systems that are under study, of low Technical Readiness Level (TRL), or of new designs undergoing development and testing.

The lidar systems in Section 1 are designed for surface or airborne platforms for measurements of clouds, aerosols, methane, water vapor pressure, temperature and winds. Lasers capable of generating radiation from 300 nm to 1100 nm are available, as is a corresponding range of sensitive photon detectors. The various systems provide high sensitivity measurements based on returns from backscatter, or Raman scattering, including intensity and polarization. Measurements of the frequency (Doppler) shift of light scattered from various atmospheric constitutes can also be made.

The passive optical sensors in Section 2 operate on the surface or from aircraft. The Solar Disk Sextant (SDS) is the single balloon-borne platform. The systems consist of radiometers and spectrometers that measure atmospheric
parameters such as trace gases, aerosols, optical properties, or altitude profiles of various species. The systems operate mostly in the spectral bands from 300 nm to 940 nm; one system (SMART) reaches 1,230 nm. Spatial resolution is typically in the 0.5–1 km range; spectral resolution is generally in the 0.5 nm range.

Section 3 contains summaries of microwave sensors that are deployed on the surface or in aircraft. The systems consist of both active (radar) and passive (radiometer) systems. These systems are important for studies of processes involving water in various forms. The dielectric properties of water in various forms affect microwave brightness temperatures, which are separable into atmospheric parameters such as rainfall rate and key elements of the hydrological cycle. The radar systems operate in the range from 9.6 GHz to 94 GHz and have measurement accuracies from -5 to 1 dBZ; radiometers operate in the 50 GHz to 874 GHz range with accuracies from 0.5 to 1 degree K.

An important in situ capability is discussed in Section 4. COMMIT is a complete mobile facility housed in a 20-
foot trailer that had traveled widely over the globe in conjunction with SMART (passive optical) to support numer-
ous fi eld and validation campaigns.

Section 5 covers systems that are not yet available for experimental operations. Seven instruments fall into this
category with at least one in each of the three areas previously described. Four of the systems are entirely new designs
while the remaining three are improvements over existing systems. All of the instruments are intended to support
and contribute to future space missions which include GPM, IceSat-2, ASCENDS, ACE, Geo-CAPE, and 3D
Winds.

Instrument systems evolve and change over time and therefore the report will be updated as required, typically every
three to fi ve years. Th e previous report was completed in 2005; 18 new instruments programs began since that time
and are included in the 2010 report. A copy of this report can be found on the Laboratory for Atmospheres Web
site at http://atmospheres.gsfc.nasa.gov/.

We wish to thank all of the Laboratory members who contributed material on the various instrument systems, and
especially the eff orts of Chuck Cote (GEST/Caelum Research) who managed and coordinated the report prepara-
tion as well as Judith Clark (TIMS) and Omega Williams for their formatting, proofreading, editing, and printing
support.

Sincerely,

Dr. William Lau's signature

William K.-M. Lau, Chief

Chares Cote's signature

James R. Irons, Associate Chief