Cross-secondary spectra (top row) and cross-correlations (bottom row) from December 4–5, 2023. The observation has been split into four parts of equal length in time, shown in chronological order. The colors denote the complex phase of the cross-secondary spectra, while their brightness denotes the power. The cross-correlation functions are obtained as the Fourier transform of the cross-secondary spectra. They illustrate the temporal shift corresponding to the linear phase evolution in the cross-spectra.