Evaluation of downward and upward solar irradiances simulated by the Integrated Forecasting System of ECMWF using airborne observations above Arctic low-level clouds
<p>The simulations of upward and downward irradiances by the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts are compared with broadband solar irradiance measurements from the Arctic CLoud Observations Using airborne measurements during polar Day (...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2024-04-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/24/4157/2024/acp-24-4157-2024.pdf |
| _version_ | 1797217532318318592 |
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| author | H. Müller A. Ehrlich E. Jäkel J. Röttenbacher B. Kirbus M. Schäfer R. J. Hogan R. J. Hogan M. Wendisch |
| author_facet | H. Müller A. Ehrlich E. Jäkel J. Röttenbacher B. Kirbus M. Schäfer R. J. Hogan R. J. Hogan M. Wendisch |
| author_sort | H. Müller |
| collection | DOAJ |
| description | <p>The simulations of upward and downward irradiances by the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts are compared with broadband solar irradiance measurements from the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign. For this purpose, offline radiative transfer simulations were performed with the ecRad radiation scheme using the operational IFS output. The simulations of the downward solar irradiance agree within the measurement uncertainty. However, the IFS underestimates the reflected solar irradiances above sea ice significantly by <span class="inline-formula">−</span>35 <span class="inline-formula">W m<sup>−2</sup></span>. Above open ocean, the agreement is closer, with an overestimation of 28 <span class="inline-formula">W m<sup>−2</sup></span>. A sensitivity study using measured surface and cloud properties is performed with ecRad to quantify the contributions of the surface albedo, cloud fraction, ice and liquid water path and cloud droplet number concentration to the observed bias. It shows that the IFS sea ice albedo climatology underestimates the observed sea ice albedo, causing more than 50 % of the bias. Considering the higher variability of in situ observations in the parameterization of the cloud droplet number concentration leads to a smaller bias of <span class="inline-formula">−</span>27 <span class="inline-formula">W m<sup>−2</sup></span> above sea ice and a larger bias of 48 <span class="inline-formula">W m<sup>−2</sup></span> above open ocean by increasing the range from 36–69 to 36–200 <span class="inline-formula">cm<sup>−3</sup></span>. Above sea ice, realistic surface albedos, cloud droplet number concentrations and liquid water paths contribute most to the bias improvement. Above open ocean, realistic cloud fractions and liquid water paths are most important for reducing the model–observation differences.</p> |
| first_indexed | 2024-04-24T12:03:21Z |
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| id | doaj.art-c516c76f5c3f4cc4b9393c289b6bdf86 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-24T12:03:21Z |
| publishDate | 2024-04-01 |
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| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-c516c76f5c3f4cc4b9393c289b6bdf862024-04-08T13:19:28ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242024-04-01244157417510.5194/acp-24-4157-2024Evaluation of downward and upward solar irradiances simulated by the Integrated Forecasting System of ECMWF using airborne observations above Arctic low-level cloudsH. Müller0A. Ehrlich1E. Jäkel2J. Röttenbacher3B. Kirbus4M. Schäfer5R. J. Hogan6R. J. Hogan7M. Wendisch8Leipzig Institute for Meteorology (LIM), Leipzig University, Leipzig, GermanyLeipzig Institute for Meteorology (LIM), Leipzig University, Leipzig, GermanyLeipzig Institute for Meteorology (LIM), Leipzig University, Leipzig, GermanyLeipzig Institute for Meteorology (LIM), Leipzig University, Leipzig, GermanyLeipzig Institute for Meteorology (LIM), Leipzig University, Leipzig, GermanyLeipzig Institute for Meteorology (LIM), Leipzig University, Leipzig, GermanyEuropean Centre for Medium-Range Weather Forecasts, Reading, United KingdomDepartment of Meteorology, University of Reading, Reading, United KingdomLeipzig Institute for Meteorology (LIM), Leipzig University, Leipzig, Germany<p>The simulations of upward and downward irradiances by the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts are compared with broadband solar irradiance measurements from the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign. For this purpose, offline radiative transfer simulations were performed with the ecRad radiation scheme using the operational IFS output. The simulations of the downward solar irradiance agree within the measurement uncertainty. However, the IFS underestimates the reflected solar irradiances above sea ice significantly by <span class="inline-formula">−</span>35 <span class="inline-formula">W m<sup>−2</sup></span>. Above open ocean, the agreement is closer, with an overestimation of 28 <span class="inline-formula">W m<sup>−2</sup></span>. A sensitivity study using measured surface and cloud properties is performed with ecRad to quantify the contributions of the surface albedo, cloud fraction, ice and liquid water path and cloud droplet number concentration to the observed bias. It shows that the IFS sea ice albedo climatology underestimates the observed sea ice albedo, causing more than 50 % of the bias. Considering the higher variability of in situ observations in the parameterization of the cloud droplet number concentration leads to a smaller bias of <span class="inline-formula">−</span>27 <span class="inline-formula">W m<sup>−2</sup></span> above sea ice and a larger bias of 48 <span class="inline-formula">W m<sup>−2</sup></span> above open ocean by increasing the range from 36–69 to 36–200 <span class="inline-formula">cm<sup>−3</sup></span>. Above sea ice, realistic surface albedos, cloud droplet number concentrations and liquid water paths contribute most to the bias improvement. Above open ocean, realistic cloud fractions and liquid water paths are most important for reducing the model–observation differences.</p>https://acp.copernicus.org/articles/24/4157/2024/acp-24-4157-2024.pdf |
| spellingShingle | H. Müller A. Ehrlich E. Jäkel J. Röttenbacher B. Kirbus M. Schäfer R. J. Hogan R. J. Hogan M. Wendisch Evaluation of downward and upward solar irradiances simulated by the Integrated Forecasting System of ECMWF using airborne observations above Arctic low-level clouds Atmospheric Chemistry and Physics |
| title | Evaluation of downward and upward solar irradiances simulated by the Integrated Forecasting System of ECMWF using airborne observations above Arctic low-level clouds |
| title_full | Evaluation of downward and upward solar irradiances simulated by the Integrated Forecasting System of ECMWF using airborne observations above Arctic low-level clouds |
| title_fullStr | Evaluation of downward and upward solar irradiances simulated by the Integrated Forecasting System of ECMWF using airborne observations above Arctic low-level clouds |
| title_full_unstemmed | Evaluation of downward and upward solar irradiances simulated by the Integrated Forecasting System of ECMWF using airborne observations above Arctic low-level clouds |
| title_short | Evaluation of downward and upward solar irradiances simulated by the Integrated Forecasting System of ECMWF using airborne observations above Arctic low-level clouds |
| title_sort | evaluation of downward and upward solar irradiances simulated by the integrated forecasting system of ecmwf using airborne observations above arctic low level clouds |
| url | https://acp.copernicus.org/articles/24/4157/2024/acp-24-4157-2024.pdf |
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