| DOI: | 10.2172/1036481
|
| 报告号: | DOE/ER64569-2
|
| 报告题名: | Parameterization and analysis of 3-D radiative transfer in clouds |
| 作者: | Varnai, Tamas
|
| 出版年: | 2012
|
| 发表日期: | 2012-03-16
|
| 国家: | 美国
|
| 语种: | 英语
|
| 英文关键词: | cloud
; solar radiation
; three-dimensional
|
| 中文主题词: | 大气辐射
; 散射
; 太阳辐射
; 云
; 雷达
|
| 主题词: | ATMOSPHERIC RADIATION
; SCATTERING
; SOLAR RADIATION
; CLOUDS
; RADAR
|
| 英文摘要: | This report provides a summary of major accomplishments from the project. The project examines the impact of radiative interactions between neighboring atmospheric columns, for example clouds scattering extra sunlight toward nearby clear areas. While most current cloud models don't consider these interactions and instead treat sunlight in each atmospheric column separately, the resulting uncertainties have remained unknown. This project has provided the first estimates on the way average solar heating is affected by interactions between nearby columns. These estimates have been obtained by combining several years of cloud observations at three DOE Atmospheric Radiation Measurement (ARM) Climate Research Facility sites (in Alaska, Oklahoma, and Papua New Guinea) with simulations of solar radiation around the observed clouds. The importance of radiative interactions between atmospheric columns was evaluated by contrasting simulations that included the interactions with those that did not. This study provides lower-bound estimates for radiative interactions: It cannot consider interactions in cross-wind direction, because it uses two-dimensional vertical cross-sections through clouds that were observed by instruments looking straight up as clouds drifted aloft. Data from new DOE scanning radars will allow future radiative studies to consider the full three-dimensional nature of radiative processes. The results reveal that two-dimensional radiative interactions increase overall day-and-night average solar heating by about 0.3, 1.2, and 4.1 Watts per meter square at the three sites, respectively. This increase grows further if one considers that most large-domain cloud simulations have resolutions that cannot specify small-scale cloud variability. For example, the increases in solar heating mentioned above roughly double for a fairly typical model resolution of 1 km. The study also examined the factors that shape radiative interactions between atmospheric columns and found that local effects were often much larger than the overall values mentioned above, and were especially large for high sun and near convective clouds such as cumulus. The study also found that statistical methods such as neural networks appear promising for enabling cloud models to consider radiative interactions between nearby atmospheric columns. Finally, through collaboration with German scientists, the project found that new methods (especially one called stepwise kriging) show great promise in filling gaps between cloud radar scans. If applied to data from the new DOE scanning cloud radars, these methods can yield large, continuous three-dimensional cloud structures for future radiative simulations. |
| URL: | http://www.osti.gov/scitech/servlets/purl/1036481
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| Citation statistics: |
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| 资源类型: | 研究报告
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/40846
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| Appears in Collections: | 过去全球变化的重建
影响、适应和脆弱性
科学计划与规划
气候变化与战略
全球变化的国际研究计划
气候减缓与适应
气候变化事实与影响
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| File Name/ File Size |
Content Type |
Version |
Access |
License |
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| 1036481.pdf（63KB） | 研究报告 | -- | 开放获取 | | View
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| Recommended Citation: | |
Varnai, Tamas. Parameterization and analysis of 3-D radiative transfer in clouds. 2012-01-01.
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