DOI: 10.1002/jgrd.50354
论文题名: On the scale estimation using truncated swath measurements from low Earth orbiting satellites
作者: Liu Q.
刊名: Journal of Geophysical Research Atmospheres
ISSN: 21698996
出版年: 2013
卷: 118, 期: 10 起始页码: 4816
结束页码: 4833
语种: 英语
英文关键词: cloud size
; mean object area fraction (MOAF)
; MOAF-equivalent radius (MER)
; MODIS
; scale estimation
; swath truncation
Scopus关键词: Masks
; Pixels
; Area fraction
; MOAF-equivalent radius (MER)
; MODIS
; Scale estimation
; swath truncation
; Radiometers
; cloud
; data assimilation
; Earth
; EOS
; MODIS
; satellite
; swath bathymetry
英文摘要: Truncation effect caused by limited swath width of low Earth orbiting (LEO) satellites results in inevitable underestimation of object scale when using pixel-counting methods. A new approach is proposed to obtain more accurate object scale through truncated measurements. The approach is based upon the mean object area fraction (MOAF), which depicts the relative population of object points in a varying-size domain and proves to be less sensitive to truncation effect. The MOAF-equivalent radius (MER) is deduced by comparing the actual MOAF with the standard one inferred from a circle object. Numerical simulations are implemented to demonstrate the MER characteristics. In contrast to area-equivalent radius (AER) that is merely determined by the absolute amount of object points, MER relies on the overall spatial structure of the object. For objects with irregular shapes, the MER value is generally smaller than AER in the absence of truncation. Nevertheless, taking the actual AER as true scale, MER has significantly reduced biases compared to AER once the object is truncated. This advantage can be reinforced when focusing on size statistics of analogous objects, because negative and positive biases associated with various truncation situations coexist in MER, against the uniform negative biases of AER. When applied to MODIS cloud mask data that are restricted in individual granules, MER has consistently larger values than AER for most truncated clouds. Compared with the explicitly problematic estimation from AER due to truncation, MER offers a notable elevation on the estimated cloud size and gets closer to the truth. Key Points A method is proposed to estimate object scale using truncated swath measurementsMean object area fraction (MOAF) is capable of mitigating truncation effectsMOAF-equivalent radius (MER) has lower biases than pixel-counting methods ©2013. American Geophysical Union. All Rights Reserved. 资助项目: 40805007
; 41175032
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63708
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: School of Earth and Space Sciences, University of Science and Technology of China, Anhui Hefei 230026, China
Recommended Citation:
Liu Q.. On the scale estimation using truncated swath measurements from low Earth orbiting satellites[J]. Journal of Geophysical Research Atmospheres,2013-01-01,118(10)