On the Limits of CALIOP for Constraining Modeled Free Tropospheric Aerosol

Duncan Watson-Parris, Nick Schutgens, David Winker, Sharon P. Burton, Richard A. Ferrare, Philip Stier

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

The spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument provides valuable information on the vertical distribution of global aerosol and is often used to evaluate vertical aerosol distributions in general circulation models (GCMs). Here we show, however, that the detection limit of the CALIOP retrievals mean background aerosol is not detected, leading to substantially skewed statistics that moreover differ significantly by product. In the CALIOP Level 2 product this missing low-backscatter aerosol results in the retrieved aerosol distribution significantly overrepresenting aerosol backscatter and extinction in the middle and upper troposphere if taken to be representative of the undetected aerosol. The CALIOP Level 3 product assumes no aerosol where none is detected, which then leads to an underestimation in the aerosol extinction profile in the upper troposphere. Using the ECHAM-HAM GCM, we estimate that the mean fraction of aerosol undetected by CALIOP daytime (nighttime) retrievals is 41% (44%) globally.

Original languageEnglish
Pages (from-to)9260-9266
Number of pages7
JournalGeophysical Research Letters
Volume45
Issue number17
Early online date3 Aug 2018
DOIs
Publication statusPublished - 16 Sep 2018

Fingerprint

optical radar
aerosols
aerosol
polarization
backscatter
general circulation model
troposphere
extinction
CALIOP
retrieval
vertical distribution
daytime
products

Keywords

  • aerosol
  • free troposphere
  • model evaluation

Cite this

Watson-Parris, D., Schutgens, N., Winker, D., Burton, S. P., Ferrare, R. A., & Stier, P. (2018). On the Limits of CALIOP for Constraining Modeled Free Tropospheric Aerosol. Geophysical Research Letters, 45(17), 9260-9266. https://doi.org/10.1029/2018GL078195
Watson-Parris, Duncan ; Schutgens, Nick ; Winker, David ; Burton, Sharon P. ; Ferrare, Richard A. ; Stier, Philip. / On the Limits of CALIOP for Constraining Modeled Free Tropospheric Aerosol. In: Geophysical Research Letters. 2018 ; Vol. 45, No. 17. pp. 9260-9266.
@article{eb1b91248f59461481823f801aae84b9,
title = "On the Limits of CALIOP for Constraining Modeled Free Tropospheric Aerosol",
abstract = "The spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument provides valuable information on the vertical distribution of global aerosol and is often used to evaluate vertical aerosol distributions in general circulation models (GCMs). Here we show, however, that the detection limit of the CALIOP retrievals mean background aerosol is not detected, leading to substantially skewed statistics that moreover differ significantly by product. In the CALIOP Level 2 product this missing low-backscatter aerosol results in the retrieved aerosol distribution significantly overrepresenting aerosol backscatter and extinction in the middle and upper troposphere if taken to be representative of the undetected aerosol. The CALIOP Level 3 product assumes no aerosol where none is detected, which then leads to an underestimation in the aerosol extinction profile in the upper troposphere. Using the ECHAM-HAM GCM, we estimate that the mean fraction of aerosol undetected by CALIOP daytime (nighttime) retrievals is 41{\%} (44{\%}) globally.",
keywords = "aerosol, free troposphere, model evaluation",
author = "Duncan Watson-Parris and Nick Schutgens and David Winker and Burton, {Sharon P.} and Ferrare, {Richard A.} and Philip Stier",
year = "2018",
month = "9",
day = "16",
doi = "10.1029/2018GL078195",
language = "English",
volume = "45",
pages = "9260--9266",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "17",

}

Watson-Parris, D, Schutgens, N, Winker, D, Burton, SP, Ferrare, RA & Stier, P 2018, 'On the Limits of CALIOP for Constraining Modeled Free Tropospheric Aerosol' Geophysical Research Letters, vol. 45, no. 17, pp. 9260-9266. https://doi.org/10.1029/2018GL078195

On the Limits of CALIOP for Constraining Modeled Free Tropospheric Aerosol. / Watson-Parris, Duncan; Schutgens, Nick; Winker, David; Burton, Sharon P.; Ferrare, Richard A.; Stier, Philip.

In: Geophysical Research Letters, Vol. 45, No. 17, 16.09.2018, p. 9260-9266.

Research output: Contribution to JournalArticleAcademicpeer-review

TY - JOUR

T1 - On the Limits of CALIOP for Constraining Modeled Free Tropospheric Aerosol

AU - Watson-Parris, Duncan

AU - Schutgens, Nick

AU - Winker, David

AU - Burton, Sharon P.

AU - Ferrare, Richard A.

AU - Stier, Philip

PY - 2018/9/16

Y1 - 2018/9/16

N2 - The spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument provides valuable information on the vertical distribution of global aerosol and is often used to evaluate vertical aerosol distributions in general circulation models (GCMs). Here we show, however, that the detection limit of the CALIOP retrievals mean background aerosol is not detected, leading to substantially skewed statistics that moreover differ significantly by product. In the CALIOP Level 2 product this missing low-backscatter aerosol results in the retrieved aerosol distribution significantly overrepresenting aerosol backscatter and extinction in the middle and upper troposphere if taken to be representative of the undetected aerosol. The CALIOP Level 3 product assumes no aerosol where none is detected, which then leads to an underestimation in the aerosol extinction profile in the upper troposphere. Using the ECHAM-HAM GCM, we estimate that the mean fraction of aerosol undetected by CALIOP daytime (nighttime) retrievals is 41% (44%) globally.

AB - The spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument provides valuable information on the vertical distribution of global aerosol and is often used to evaluate vertical aerosol distributions in general circulation models (GCMs). Here we show, however, that the detection limit of the CALIOP retrievals mean background aerosol is not detected, leading to substantially skewed statistics that moreover differ significantly by product. In the CALIOP Level 2 product this missing low-backscatter aerosol results in the retrieved aerosol distribution significantly overrepresenting aerosol backscatter and extinction in the middle and upper troposphere if taken to be representative of the undetected aerosol. The CALIOP Level 3 product assumes no aerosol where none is detected, which then leads to an underestimation in the aerosol extinction profile in the upper troposphere. Using the ECHAM-HAM GCM, we estimate that the mean fraction of aerosol undetected by CALIOP daytime (nighttime) retrievals is 41% (44%) globally.

KW - aerosol

KW - free troposphere

KW - model evaluation

UR - http://www.scopus.com/inward/record.url?scp=85053279202&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85053279202&partnerID=8YFLogxK

U2 - 10.1029/2018GL078195

DO - 10.1029/2018GL078195

M3 - Article

VL - 45

SP - 9260

EP - 9266

JO - Geophysical Research Letters

JF - Geophysical Research Letters

SN - 0094-8276

IS - 17

ER -