New capabilities for space-based cloud and aerosols measurements: The Cloud-Aerosol Transport System (CATS)
Abstract
Current uncertainties in cloud and aerosol properties limit our ability to accurately model the Earth's climate system and predict climate change. These limitations are due primarily to difficulties in adequately measuring aerosols and clouds on a global scale. NASA's A-Train satellites provide an unprecedented opportunity to address these uncertainties. In particular, the Cloud-Aerosol Lidar Infrared Pathfinder Spaceborne Observations (CALIPSO) satellite provides vertical profiles of cloud and aerosol properties. The CALIOP lidar onboard CALIPSO has reached its seventh year of operation, well past its expected lifetime. The ATLID lidar on EarthCARE is not expected to launch until 2016 or later. If the CALIOP lidar fails before a new mission is operational, there will be a gap in global lidar measurements. The Cloud-Aerosol Transport System (CATS), built at NASA Goddard Space Flight Center as a payload for the International Space Station (ISS), is set to launch in the summer of 2014. CATS is an elastic backscatter lidar with three wavelengths (1064, 532, 355 nm) and HSRL capability at 532 nm. Depolarization measurements will be made at all three wavelengths. The ISS orbit is a 51 degree inclination orbit at an altitude of about 405 km. This orbit provides more comprehensive coverage of the tropics and mid-latitudes than sun-synchronous orbiting sensors, with nearly a three day repeat cycle. Thus, science applications of CATS include cloud and aerosol climate studies, air quality monitoring, and smoke/volcanic plume tracking. The primary science objectives of CATS include: continuing the CALIPSO aerosol and cloud vertical profile data record, providing near real time data to support operational applications such as air quality modeling, and advancing technology in support of future mission development using the HSRL channel. Furthermore, the vertical profiles of cloud and aerosol properties provided by CATS will complement current and future passive satellite sensors. In preparation for launch, simulations of the CATS lidar signal are produced using GEOS5 model data. An example of the simulated CATS attenuated total backscatter for the 532 nm parallel channel is shown in Figure 1 using the GEOS5 model forecast from 15 July 2009. The CATS simulations suggest the signal-to-noise ratio (SNR) and minumim detectable backscatter at 532 nm will be better than CALIPSO during nighttime and very similar during daytime operation. An overview of the CATS mission, science objectives and simulated data will be provided. Figure 1. Simulated CATS attenuated total backscatter for the 532 nm parallel channel using the GEOS5 model forecast data from 15 July 2009.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.A43D0302Y
- Keywords:
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- 0305 ATMOSPHERIC COMPOSITION AND STRUCTURE Aerosols and particles;
- 0320 ATMOSPHERIC COMPOSITION AND STRUCTURE Cloud physics and chemistry;
- 0360 ATMOSPHERIC COMPOSITION AND STRUCTURE Radiation: transmission and scattering