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Remote sensing of tropical tropopause layer radiation balance using A-train measurements

Feldman, D. R. and L'Ecuyer, T. S. and Liou, K. N. and Yung, Y. L. (2008) Remote sensing of tropical tropopause layer radiation balance using A-train measurements. Journal of Geophysical Research D, 113 (D21). D21113. ISSN 0148-0227.

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Determining the level of zero net radiative heating (LZH) is critical to understanding parcel trajectory in the Tropical Tropopause Layer (TTL) and associated stratospheric hydration processes. Previous studies of the TTL radiative balance have focused on using radiosonde data, but remote sensing measurements from polar-orbiting satellites may provide the relevant horizontal and vertical information for assessing TTL solar heating and infrared cooling rates, especially across the Pacific Ocean. CloudSat provides a considerable amount of vertical information about the distribution of cloud properties relevant to heating rate analysis. The ability of CloudSat measurements and ancillary information to constrain LZH is explored. We employ formal error propagation analysis for derived heating rate uncertainty given the CloudSat cloud property retrieval algorithms. Estimation of the LZH to within approximately 0.5 to 1 km is achievable with CloudSat, but it has a low-altitude bias because the radar is unable to detect thin cirrus. This can be remedied with the proper utilization of Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) lidar backscatter information. By utilizing an orbital simulation with the GISS data set, we explore the representativeness of non-cross-track scanning active sounders in terms of describing the LZH distribution. In order to supplement CloudSat, we explore the ability of Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Scanning Radiometer-EOS (AMSR-E) to constrain LZH and find that these passive sounders are useful where the cloud top height does not exceed 7 km. The spatiotemporal distributions of LZH derived from CloudSat and CALIPSO measurements are presented which suggest that thin cirrus have a limited effect on LZH mean values but affect LZH variability.

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Additional Information:©2008. American Geophysical Union. Received 20 March 2008; accepted 8 August 2008; published 12 November 2008. This research was supported by the NASA Earth Systems Science Fellowship, grant NNG05GP90H. Invaluable technical support was provided by Tony Clough, Mark Iacono, and Mark Shepard at AER, Inc. The authors would also like to acknowledge the help provided by Jonathan Jiang, Duane Waliser, Brian Kahn, and Frank Li at NASA JPL, Tony Del Genio at NASA GISS, Sally McFarlane of PNNL, Zhiming Kuang of Harvard, and the Yuk Yung Radiation Group including Jack Margolis, Vijay Natraj, Kuai Le, and King-Fai Li. Additionally, the two anonymous reviewers for the paper provided very useful advice. Finally, the CloudSat Data Processing Team provided crucial technical support.
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Subject Keywords:CloudSat, TTL, Radiation
Issue or Number:D21
Record Number:CaltechAUTHORS:FELjgrd08b
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Official Citation:Feldman, D. R., T. S. L'Ecuyer, K. N. Liou, and Y. L. Yung (2008), Remote sensing of tropical tropopause layer radiation balance using A-train measurements, J. Geophys. Res., 113, D21113, doi:10.1029/2008JD010158.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:12544
Deposited By: Archive Administrator
Deposited On:16 Dec 2008 21:07
Last Modified:03 Oct 2019 00:29

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