Noctilucent clouds observed from the ground: sensitivity to mesospheric parameters and long-term time series

Earth, Planets and Space

Table 1 Two-dimensional regression analysis: coefficients for Equation 1

Time series	Year range	b₁number/year	b₂number/Lyα	b ₃	Lag (years)
Moscow relative NLC number	1990 to 2013	−0.001 ± 0.009	−0.15 ± 0.10	1.1 ± 0.5	0
Moscow relative NLC brightness	1990 to 2013	−0.040 ± 0.241	−3.48 ± 2.52	23.7 ± 12.4	0
Lithuanian relative NLC number	1992 to 2013	0.216 ± 0.317	−5.27 ± 3.15	50.3 ± 15.0	1
Canadian relative NLC number	1990 to 2013	0.048 ± 0.310	0.66 ± 3.13	10.9 ± 15.5	2
PMC frequency	1990 to 2013	−0.030 ± 0.035	−0.68 ± 0.36	5.0 ± 1.8	0
PMC albedo	1990 to 2013	−0.009 ± 0.031	−0.13 ± 0.28	5.9 ± 1.5	2

The table contains the results of ground-based NLC observations and of the space-borne PMC measurements at 50 to 64°N (the latter are consistent with DeLand and Thomas (2014) and are provided by M. DeLand). Lag equal to 0 means that the NLC/PMC cycle is exactly in the anti-correlation with the solar cycle, while positive lag means that the maximum of NLC/PMC is delayed with respect to minimum of Ly alpha flux.