Seasonal variation of mesospheric iron layers at Arecibo: First results from low-latitudes

Abstract

We present the annual variation of the distribution of neutral iron of the low-latitude mesopause region measured at the Arecibo Observatory using resonance fluorescence lidar. A comparison was made between our low-latitude measurements and similar mid-and high-latitude observations of Fe column abundance, centroid height, and RMS width of the layer. We find that the annual variation of the height and width of the layer are essentially anti-correlated with previous measurements, while the column abundance lags its midlatitude counterpart by roughly three months. We suggest that the latitudinal differences in Fe layer properties result from variations in the distribution of mesospheric ozone and O2, which in turn affect the iron chemistry at the two latitudes.