Daily variability of cloud fraction from EPIC observations
Abstract
The Earth Polychromatic Imaging Camera (EPIC) aboard the Deep Space Climate Observatory (DSCOVR) is located at the L1 Lagrangian point, approximately 1.5 million kilometers away. From this perspective, EPIC offers a global view of the Earth and captures its atmosphere at different locations and time of the day; the left edge of the images corresponds to sunrise while the right edge to sunset, being noon in the areas in the middle of the image. Taking advantage of that unique feature, we investigate the cloud fraction over ocean compared to land, and study the daily evolution providing a spatial (latitude) and temporal (daily) analysis for the latitudes from 60°S to 60°N. We use four years of data starting in June 2015 and we observe that the behavior over ocean has a distinctive convex shape, in agreement with previous investigations using data from the International Satellite Cloud Climatology Project (ISCCP), with higher cloud fractions at early morning and late afternoon. However, we do not find such pattern over land, where the behavior is mainly flat with a slight increase in the afternoon. Since EPIC's pixel resolution depends on the VZA, we investigate a variety of situations to analyze its impact on the results. We present the analysis of the cloud fraction for different latitudes, for the globe as a whole and separately for each Hemisphere, and study the effect of the viewing zenith angle on cloud fraction retrievals.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A43L2977D
- Keywords:
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- 3311 Clouds and aerosols;
- ATMOSPHERIC PROCESSES;
- 3359 Radiative processes;
- ATMOSPHERIC PROCESSES;
- 3360 Remote sensing;
- ATMOSPHERIC PROCESSES