Simultaneous Observation Of Sporadic Potassium And Sodium Layers Over Sao Jose Dos Campos, Brazil (23.1 Degrees S, 45.9 Degrees W)

Sporadic potassium (K-s) and sodium (Na-s) layers were investigated using more than 1,500 h of simultaneous Na/K LIDAR data at Sao Jose dos Campos, Brazil (23.1 degrees S, 45.9 degrees W). These events were observed on more than 88% of the analyzed nights. Although Na and K are both alkali metals, their sporadic layers show different behaviors. The Na-s layers were in general 0.7 km wider and occurred similar to 2 km higher than K-s layers. Moreover, the Na-s layers progression is faster than that of K-s layers not only in the process of reaching their maximum amplitude but also in terms of dissipation. Our study showed that most N-s events (80% of K-s layers and 90% of Na-s layers) have a strength factor of upto 5. Moreover, on average, K-s presented a strength factor similar to 1.3 times stronger than that of Na-s. The relative frequency of occurrence for both K-s and Na-s layers exhibits an almost semiannual variation, with maxima in January/October and February/September, respectively. On the other hand, no similar variation was observed in the peak density or in the peak height. The peak density shows an annual variation, with a maximum occurring during winter for K-s events and a semiannual variation with a maxima occurring at the equinoxes for Na-s. Different seasonal behaviors were also seen in the peak height of the identified layers, with K-s presenting a semiannual variation with maxima around January/October, while an annual variation occurred in Na-s with lower layers occurring around winter.