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Study of the Effect of Temporal Sampling Frequency on DSCOVR Observations Using the GEOS-5 Nature Run ResultsThis is the second part of a study on how temporal sampling frequency affects satellite retrievals in support of the Deep Space Climate Observatory (DSCOVR) mission. Continuing from Part 1, which looked at Earth's radiation budget, this paper presents the effect of sampling frequency on DSCOVR-derived cloud fraction. The output from NASA's Goddard Earth Observing System version 5 (GEOS-5) Nature Run is used as the "truth". The effect of temporal resolution on potential DSCOVR observations is assessed by subsampling the full Nature Run data. A set of metrics, including uncertainty and absolute error in the subsampled time series, correlation between the original and the subsamples, and Fourier analysis have been used for this study. Results show that, for a given sampling frequency, the uncertainties in the annual mean cloud fraction of the sunlit half of the Earth are larger over land than over ocean. Analysis of correlation coefficients between the subsamples and the original time series demonstrates that even though sampling at certain longer time intervals may not increase the uncertainty in the mean, the subsampled time series is further and further away from the "truth" as the sampling interval becomes larger and larger. Fourier analysis shows that the simulated DSCOVR cloud fraction has underlying periodical features at certain time intervals, such as 8, 12, and 24 h. If the data is subsampled at these frequencies, the uncertainties in the mean cloud fraction are higher. These results provide helpful insights for the DSCOVR temporal sampling strategy.
Document ID
20170000990
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Holdaway, Daniel
(Universities Space Research Association Greenbelt, MD, United States)
Yang, Yuekui
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
January 31, 2017
Publication Date
May 20, 2016
Publication Information
Publication: Remote Sensing
Volume: 8
Issue: 5
Subject Category
Earth Resources And Remote Sensing
Report/Patent Number
GSFC-E-DAA-TN38805
Funding Number(s)
CONTRACT_GRANT: NNX15AB51G
CONTRACT_GRANT: NNG11HP16A
Distribution Limits
Public
Copyright
Other
Keywords
GEOS-5
DSCOVR
EPIC
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