NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Microphysical Properties of Tropical Tropopause Layer CirrusPervasive cirrus clouds in the tropical tropopause layer (TTL) play an important role in determining the composition of stratospheric air through dehydration of tropospheric air entering the stratosphere. This dehydration affects Earth's energy budget and climate, yet uncertainties remain regarding the microphysical processes that govern TTL cirrus. TTL cirrus were sampled with the NASA Global Hawk UAV for over 30 hr in the Western Pacific in 2014 during the Airborne Tropical TRopopause EXperiment. In situ measurements by a Fast Cloud Droplet Probe and Hawkeye probe (combination Fast Cloud Droplet Probe, Two‐Dimensional Stereo optical array probe, and Cloud Particle Imager) provided particle concentrations and sizing between 1‐ and 1,280‐μm diameter and high resolution images for habit identification. We present the variability in ice concentrations, size distributions, and habits as functions of temperature, altitude, and time since convective influence. Observed ice particles were predominantly small and quasi‐spheroidal in shape, with the percentage of quasi‐spheroids increasing with decreasing temperature. In comparison to the large fraction of the population consisting of quasi‐spheroids, faceted habits (columns, plates, rosettes, and budding rosettes) constituted a smaller percentage of the overall population and exhibited the opposite correlation with temperature. The trend of higher percentages of faceted crystals occurring at warmer temperatures may be due to diffusional growth or aggregation as particles descend through cloud, and/or the more rapid diffusional growth rate at warmer temperatures. Sampling was typically well away from deep convection, however, and very few aggregates were observed, so the trend of higher percentages of faceted habits is likely attributable to diffusional growth.
Document ID
20190025845
Acquisition Source
Langley Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Woods, Sarah ORCID
(Stratton Park Engineering Co., Inc. Boulder, CO, United States)
Lawson, R. Paul ORCID
(Stratton Park Engineering Co., Inc. Boulder, CO, United States)
Jensen, Eric ORCID
(NASA Ames Research Center Moffett Field, CA, United States)
Bui, T. P. ORCID
(NASA Ames Research Center Moffett Field, CA, United States)
Thornberry, Troy ORCID
(National Oceanic and Atmospheric Administration (NOAA) Boulder, CO, United States)
Rollins, Andrew ORCID
(National Oceanic and Atmospheric Administration (NOAA) Boulder, CO, United States)
Pfister, Leonhard ORCID
(NASA Ames Research Center Moffett Field, CA, United States)
Avery, Melody ORCID
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
June 11, 2019
Publication Date
May 4, 2018
Publication Information
Publication: Journal of Geophysical Research: Atmospheres
Publisher: American Geophysical Union
Volume: 123
Issue: 11
ISSN: 2169-897X
e-ISSN: 2169-8996
Subject Category
Meteorology And Climatology
Report/Patent Number
NF1676L-26189
Funding Number(s)
WBS: 967701.02.01.01.95
PROJECT: SCMD-EarthScienceSystem_967701
Distribution Limits
Public
Copyright
Public Use Permitted.
No Preview Available