Effects of solar activity on noise in CALIOP profiles above the South Atlantic Anomaly

V. Noel (1) , H. Chepfer (1) , C. Hoareau (1) , M. Reverdy (1) , G. Cesana (2)

1 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
2 JPL - Jet Propulsion Laboratory

We show that nighttime dark noise measurements from the spaceborne lidar CALIOP contain valuable infor-mation about the evolution of upwelling high-energy ra-diation 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 par-ticle 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 −1 , 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 pre-dict SAA noise levels will increase anew after 2014, and will affect future spaceborne lidar missions most near 2020.

Domains: Ocean, Atmosphere

V. Noel, H. Chepfer, C. Hoareau, M. Reverdy, G. Cesana. Effects of solar activity on noise in CALIOP profiles above the South Atlantic Anomaly. Atmospheric Measurement Techniques, 2014, 7, pp.1597-1603. ⟨10.5194/amt-7-1597-2014⟩. ⟨hal-01083512⟩