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Evaluation of aerosol and cloud properties in three climate models using MODIS observations and its corresponding COSP simulator, as well as their application in aerosol-cloud interactions

Saponaro, Giulia ; Sporre, Moa K. LU orcid ; Neubauer, David ; Kokkola, Harri ; Kolmonen, Pekka ; Sogacheva, Larisa ; Arola, Antti ; De Leeuw, Gerrit ; Karset, Inger H.H. and Laaksonen, Ari , et al. (2020) In Atmospheric Chemistry and Physics 20(3). p.1607-1626
Abstract

The evaluation of modelling diagnostics with appropriate observations is an important task that establishes the capabilities and reliability of models. In this study we compare aerosol and cloud properties obtained from three different climate models (ECHAM-HAM, ECHAM-HAMSALSA, and NorESM) with satellite observations using Moderate Resolution Imaging Spectroradiometer (MODIS) data. The simulator MODIS-COSP version 1.4 was implemented into the climate models to obtain MODIS-like cloud diagnostics, thus enabling model-to-model and modelto-satellite comparisons. Cloud droplet number concentrations (CDNCs) are derived identically from MODIS-COSPsimulated and MODIS-retrieved values of cloud optical depth and effective radius. For CDNC, the... (More)

The evaluation of modelling diagnostics with appropriate observations is an important task that establishes the capabilities and reliability of models. In this study we compare aerosol and cloud properties obtained from three different climate models (ECHAM-HAM, ECHAM-HAMSALSA, and NorESM) with satellite observations using Moderate Resolution Imaging Spectroradiometer (MODIS) data. The simulator MODIS-COSP version 1.4 was implemented into the climate models to obtain MODIS-like cloud diagnostics, thus enabling model-to-model and modelto-satellite comparisons. Cloud droplet number concentrations (CDNCs) are derived identically from MODIS-COSPsimulated and MODIS-retrieved values of cloud optical depth and effective radius. For CDNC, the models capture the observed spatial distribution of higher values typically found near the coasts, downwind of the major continents, and lower values over the remote ocean and land areas. However, the COSP-simulated CDNC values are higher than those observed, whilst the direct model CDNC output is significantly lower than the MODIS-COSP diagnostics. NorESM produces large spatial biases for ice cloud properties and thick clouds over land. Despite having identical cloud modules, ECHAM-HAM and ECHAM-HAM-SALSA diverge in their representation of spatial and vertical distributions of clouds. From the spatial distributions of aerosol optical depth (AOD) and aerosol index (AI), we find that NorESM shows large biases for AOD over bright land surfaces, while discrepancies between ECHAM-HAM and ECHAM-HAM-SALSA can be observed mainly over oceans. Overall, the AIs from the different models are in good agreement globally, with higher negative biases in the Northern Hemisphere. We evaluate the aerosol-cloud interactions by computing the sensitivity parameter ACICDNC D dln.CDNC/=dln.AI/on a global scale. However, 1 year of data may be considered not enough to assess the similarity or dissimilarities of the models due to large temporal variability in cloud properties. This study shows how simulators facilitate the evaluation of cloud properties and expose model deficiencies, which are necessary steps to further improve the parameterisation in climate models.

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publishing date
type
Contribution to journal
publication status
published
in
Atmospheric Chemistry and Physics
volume
20
issue
3
pages
20 pages
publisher
Copernicus GmbH
external identifiers
  • scopus:85079389644
ISSN
1680-7316
DOI
10.5194/acp-20-1607-2020
language
English
LU publication?
no
id
abd775ab-6c91-4a85-8b31-d5c157f8c2f3
date added to LUP
2020-05-18 12:07:06
date last changed
2022-04-18 22:17:22
@article{abd775ab-6c91-4a85-8b31-d5c157f8c2f3,
  abstract     = {{<p>The evaluation of modelling diagnostics with appropriate observations is an important task that establishes the capabilities and reliability of models. In this study we compare aerosol and cloud properties obtained from three different climate models (ECHAM-HAM, ECHAM-HAMSALSA, and NorESM) with satellite observations using Moderate Resolution Imaging Spectroradiometer (MODIS) data. The simulator MODIS-COSP version 1.4 was implemented into the climate models to obtain MODIS-like cloud diagnostics, thus enabling model-to-model and modelto-satellite comparisons. Cloud droplet number concentrations (CDNCs) are derived identically from MODIS-COSPsimulated and MODIS-retrieved values of cloud optical depth and effective radius. For CDNC, the models capture the observed spatial distribution of higher values typically found near the coasts, downwind of the major continents, and lower values over the remote ocean and land areas. However, the COSP-simulated CDNC values are higher than those observed, whilst the direct model CDNC output is significantly lower than the MODIS-COSP diagnostics. NorESM produces large spatial biases for ice cloud properties and thick clouds over land. Despite having identical cloud modules, ECHAM-HAM and ECHAM-HAM-SALSA diverge in their representation of spatial and vertical distributions of clouds. From the spatial distributions of aerosol optical depth (AOD) and aerosol index (AI), we find that NorESM shows large biases for AOD over bright land surfaces, while discrepancies between ECHAM-HAM and ECHAM-HAM-SALSA can be observed mainly over oceans. Overall, the AIs from the different models are in good agreement globally, with higher negative biases in the Northern Hemisphere. We evaluate the aerosol-cloud interactions by computing the sensitivity parameter ACICDNC D dln.CDNC/=dln.AI/on a global scale. However, 1 year of data may be considered not enough to assess the similarity or dissimilarities of the models due to large temporal variability in cloud properties. This study shows how simulators facilitate the evaluation of cloud properties and expose model deficiencies, which are necessary steps to further improve the parameterisation in climate models.</p>}},
  author       = {{Saponaro, Giulia and Sporre, Moa K. and Neubauer, David and Kokkola, Harri and Kolmonen, Pekka and Sogacheva, Larisa and Arola, Antti and De Leeuw, Gerrit and Karset, Inger H.H. and Laaksonen, Ari and Lohmann, Ulrike}},
  issn         = {{1680-7316}},
  language     = {{eng}},
  month        = {{02}},
  number       = {{3}},
  pages        = {{1607--1626}},
  publisher    = {{Copernicus GmbH}},
  series       = {{Atmospheric Chemistry and Physics}},
  title        = {{Evaluation of aerosol and cloud properties in three climate models using MODIS observations and its corresponding COSP simulator, as well as their application in aerosol-cloud interactions}},
  url          = {{http://dx.doi.org/10.5194/acp-20-1607-2020}},
  doi          = {{10.5194/acp-20-1607-2020}},
  volume       = {{20}},
  year         = {{2020}},
}