Revisiting cloud overlap with a merged dataset of liquid and ice cloud extinction from CloudSat and CALIPSO
We update the parameterization capturing the variation of parameters that describe how cloud occurrence (layer cloud fraction) and layer cloud optical depth (COD) distributions overlap vertically. Our updated analysis is motivated by the availability of a new dataset constructed by combining two pro...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2022-12-01
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| Series: | Frontiers in Remote Sensing |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/frsen.2022.1076471/full |
| _version_ | 1828088514934210560 |
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| author | Lazaros Oreopoulos Nayeong Cho Nayeong Cho Dongmin Lee Dongmin Lee |
| author_facet | Lazaros Oreopoulos Nayeong Cho Nayeong Cho Dongmin Lee Dongmin Lee |
| author_sort | Lazaros Oreopoulos |
| collection | DOAJ |
| description | We update the parameterization capturing the variation of parameters that describe how cloud occurrence (layer cloud fraction) and layer cloud optical depth (COD) distributions overlap vertically. Our updated analysis is motivated by the availability of a new dataset constructed by combining two products describing the two-dimensional extinction properties of liquid and ice phase clouds (and their mixtures) according to active cloud observations by the CloudSat and CALIPSO satellites. As before, cloud occurrence overlap is modeled with the decorrelation length of an inverse exponential function describing the decay with separation distance of the relative likelihood that two cloudy layers are overlapped maximally versus randomly. Similarly, cloud optical depth distribution vertical overlap is described again with a decorrelation length that describes the assumed inverse exponential decay with separation distance of the rank correlation between cloud optical depth distribution members in two cloudy layers. We derive the climatological zonal variability of these two decorrelation lengths using 4 years of observations for scenes of ∼100 km scale length, a typical grid size of numerical models used for climate simulations. As previously, we find a strong latitudinal dependence reflecting systematic differences in dominant cloud types with latitude, but substantially different magnitudes of decorrelation length compared to the previous work. The previously used parameterization form is therefore updated with new parameters to describe the latitudinal dependence of decorrelation lengths and its seasonal shift. Similar zonal patterns of decorrelation length are found when the analysis is broken down by different cloud classes. When the revised parameterization is implemented in a cloud subcolumn generator, simulated column cloud properties compare to observations quite well, and so do their associated cloud radiative effects, but improvements over the earlier version of the parameterization are marginal. |
| first_indexed | 2024-04-11T05:28:00Z |
| format | Article |
| id | doaj.art-361bc850a9634947907f0b23edb5a1cc |
| institution | Directory Open Access Journal |
| issn | 2673-6187 |
| language | English |
| last_indexed | 2024-04-11T05:28:00Z |
| publishDate | 2022-12-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Remote Sensing |
| spelling | doaj.art-361bc850a9634947907f0b23edb5a1cc2022-12-23T04:42:02ZengFrontiers Media S.A.Frontiers in Remote Sensing2673-61872022-12-01310.3389/frsen.2022.10764711076471Revisiting cloud overlap with a merged dataset of liquid and ice cloud extinction from CloudSat and CALIPSOLazaros Oreopoulos0Nayeong Cho1Nayeong Cho2Dongmin Lee3Dongmin Lee4NASA-GSFC, Earth Sciences Division, Greenbelt, MD, United StatesGESTAR-II University of Maryland Baltimore County, Baltimore, MD, United StatesNASA-GSFC, Earth Sciences Division, Greenbelt, MD, United StatesGESTAR-II Morgan State University, Baltimore, MD, United StatesNASA-GSFC, Earth Sciences Division, Greenbelt, MD, United StatesWe update the parameterization capturing the variation of parameters that describe how cloud occurrence (layer cloud fraction) and layer cloud optical depth (COD) distributions overlap vertically. Our updated analysis is motivated by the availability of a new dataset constructed by combining two products describing the two-dimensional extinction properties of liquid and ice phase clouds (and their mixtures) according to active cloud observations by the CloudSat and CALIPSO satellites. As before, cloud occurrence overlap is modeled with the decorrelation length of an inverse exponential function describing the decay with separation distance of the relative likelihood that two cloudy layers are overlapped maximally versus randomly. Similarly, cloud optical depth distribution vertical overlap is described again with a decorrelation length that describes the assumed inverse exponential decay with separation distance of the rank correlation between cloud optical depth distribution members in two cloudy layers. We derive the climatological zonal variability of these two decorrelation lengths using 4 years of observations for scenes of ∼100 km scale length, a typical grid size of numerical models used for climate simulations. As previously, we find a strong latitudinal dependence reflecting systematic differences in dominant cloud types with latitude, but substantially different magnitudes of decorrelation length compared to the previous work. The previously used parameterization form is therefore updated with new parameters to describe the latitudinal dependence of decorrelation lengths and its seasonal shift. Similar zonal patterns of decorrelation length are found when the analysis is broken down by different cloud classes. When the revised parameterization is implemented in a cloud subcolumn generator, simulated column cloud properties compare to observations quite well, and so do their associated cloud radiative effects, but improvements over the earlier version of the parameterization are marginal.https://www.frontiersin.org/articles/10.3389/frsen.2022.1076471/fullactive observationscloud overlapcloud radiative effectssubgrid variabilitydecorrelation length |
| spellingShingle | Lazaros Oreopoulos Nayeong Cho Nayeong Cho Dongmin Lee Dongmin Lee Revisiting cloud overlap with a merged dataset of liquid and ice cloud extinction from CloudSat and CALIPSO Frontiers in Remote Sensing active observations cloud overlap cloud radiative effects subgrid variability decorrelation length |
| title | Revisiting cloud overlap with a merged dataset of liquid and ice cloud extinction from CloudSat and CALIPSO |
| title_full | Revisiting cloud overlap with a merged dataset of liquid and ice cloud extinction from CloudSat and CALIPSO |
| title_fullStr | Revisiting cloud overlap with a merged dataset of liquid and ice cloud extinction from CloudSat and CALIPSO |
| title_full_unstemmed | Revisiting cloud overlap with a merged dataset of liquid and ice cloud extinction from CloudSat and CALIPSO |
| title_short | Revisiting cloud overlap with a merged dataset of liquid and ice cloud extinction from CloudSat and CALIPSO |
| title_sort | revisiting cloud overlap with a merged dataset of liquid and ice cloud extinction from cloudsat and calipso |
| topic | active observations cloud overlap cloud radiative effects subgrid variability decorrelation length |
| url | https://www.frontiersin.org/articles/10.3389/frsen.2022.1076471/full |
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