Effects of solar activity on noise in CALIOP profiles above the South Atlantic Anomaly
We show that nighttime dark noise measurements from the spaceborne lidar CALIOP contain valuable information about the evolution of upwelling high-energy radiation levels. Above the South Atlantic Anomaly (SAA), CALIOP dark noise levels fluctuate by ±6% between 2006 and 2013, and follow the known an...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-06-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | http://www.atmos-meas-tech.net/7/1597/2014/amt-7-1597-2014.pdf |
| Summary: | We show that nighttime dark noise measurements from the spaceborne lidar
CALIOP contain valuable information about the evolution of upwelling
high-energy radiation levels. Above the South Atlantic Anomaly (SAA), CALIOP
dark noise levels fluctuate by ±6% between 2006 and 2013, and follow
the known anticorrelation of local particle flux with the 11-year cycle of
solar activity (with a 1-year lag). By analyzing the geographic distribution
of noisy profiles, we are able to reproduce known findings about the SAA
region. Over the considered period, it shifts westward by
0.3° year<sup>−1</sup>, and changes in size by 6° meridionally and
2° zonally, becoming larger with weaker solar activity. All results are
in strong agreement with previous works. We predict SAA noise levels will
increase anew after 2014, and will affect future spaceborne lidar missions
most near 2020. |
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| ISSN: | 1867-1381 1867-8548 |