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Title: An Intercomparison of Microphysical Retrieval Algorithms for Upper-Tropospheric Ice Clouds

Abstract

The large horizontal extent, location in the cold upper troposphere, and ice composition make cirrus clouds important modulators of the earth’s radiation budget and climate. Cirrus cloud microphysical properties are difficult to measure and model because they are inhomogeneous in nature and their ice crystal size distribution and habit are not well characterized. Accurate retrievals of cloud properties are crucial for improving the representation of cloud scale processes in large-scale models and for accurately predicting the earth’s future climate. A number of passive and active remote sensing retrievals exist for estimating the microphysical properties of upper tropospheric clouds. We believe significant progress has been made in the evolution of these retrieval algorithms in the last decade; however, there is room for improvement. Members of the Atmospheric Radiation Measurement program (ARM) Cloud Properties Working Group are involved in an intercomparison of optical depth (tau), ice water path, and characteristic particle size in ice clouds retrieved using ground-based instruments. The goals of this intercomparison are to evaluate the accuracy of state-of-the-art algorithms, quantify the uncertainties, and make recommendations for improvement. Currently, there is significant scatter in the algorithms for difficult clouds with very small optical depths (tau<0.3) and thick ice clouds (tau>1).more » The good news is that for thin cirrus (0.3« less

Authors:
; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
985043
Report Number(s):
PNNL-SA-48156
Journal ID: ISSN 0003-0007; ISSN 1520-0477; KP1205010; TRN: US201016%%1657
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Bulletin of the American Meteorological Society, 88(2):191-204; Journal Volume: 88; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 97 MATHEMATICAL METHODS AND COMPUTING; ALGORITHMS; ICE; CLOUDS; PARTICLE SIZE; REMOTE SENSING; SATELLITES; TROPOSPHERE; WATER; PHYSICAL PROPERTIES; AIRCRAFT; COMPARATIVE EVALUATIONS

Citation Formats

Comstock, Jennifer M., d'Entremont, Robert, DeSlover, Daniel, Mace, Gerald G., Matrosov, S. Y., McFarlane, Sally A., Minnis, Patrick, Mitchell, David, Sassen, Kenneth, Shupe, Matthew D., Turner, David D., and Wang, Zhien. An Intercomparison of Microphysical Retrieval Algorithms for Upper-Tropospheric Ice Clouds. United States: N. p., 2007. Web. doi:10.1175/BAMS-88-2-191.
Comstock, Jennifer M., d'Entremont, Robert, DeSlover, Daniel, Mace, Gerald G., Matrosov, S. Y., McFarlane, Sally A., Minnis, Patrick, Mitchell, David, Sassen, Kenneth, Shupe, Matthew D., Turner, David D., & Wang, Zhien. An Intercomparison of Microphysical Retrieval Algorithms for Upper-Tropospheric Ice Clouds. United States. doi:10.1175/BAMS-88-2-191.
Comstock, Jennifer M., d'Entremont, Robert, DeSlover, Daniel, Mace, Gerald G., Matrosov, S. Y., McFarlane, Sally A., Minnis, Patrick, Mitchell, David, Sassen, Kenneth, Shupe, Matthew D., Turner, David D., and Wang, Zhien. Thu . "An Intercomparison of Microphysical Retrieval Algorithms for Upper-Tropospheric Ice Clouds". United States. doi:10.1175/BAMS-88-2-191.
@article{osti_985043,
title = {An Intercomparison of Microphysical Retrieval Algorithms for Upper-Tropospheric Ice Clouds},
author = {Comstock, Jennifer M. and d'Entremont, Robert and DeSlover, Daniel and Mace, Gerald G. and Matrosov, S. Y. and McFarlane, Sally A. and Minnis, Patrick and Mitchell, David and Sassen, Kenneth and Shupe, Matthew D. and Turner, David D. and Wang, Zhien},
abstractNote = {The large horizontal extent, location in the cold upper troposphere, and ice composition make cirrus clouds important modulators of the earth’s radiation budget and climate. Cirrus cloud microphysical properties are difficult to measure and model because they are inhomogeneous in nature and their ice crystal size distribution and habit are not well characterized. Accurate retrievals of cloud properties are crucial for improving the representation of cloud scale processes in large-scale models and for accurately predicting the earth’s future climate. A number of passive and active remote sensing retrievals exist for estimating the microphysical properties of upper tropospheric clouds. We believe significant progress has been made in the evolution of these retrieval algorithms in the last decade; however, there is room for improvement. Members of the Atmospheric Radiation Measurement program (ARM) Cloud Properties Working Group are involved in an intercomparison of optical depth (tau), ice water path, and characteristic particle size in ice clouds retrieved using ground-based instruments. The goals of this intercomparison are to evaluate the accuracy of state-of-the-art algorithms, quantify the uncertainties, and make recommendations for improvement. Currently, there is significant scatter in the algorithms for difficult clouds with very small optical depths (tau<0.3) and thick ice clouds (tau>1). The good news is that for thin cirrus (0.3},
doi = {10.1175/BAMS-88-2-191},
journal = {Bulletin of the American Meteorological Society, 88(2):191-204},
number = 2,
volume = 88,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2007},
month = {Thu Feb 01 00:00:00 EST 2007}
}