Fig. 9: Raw temperature data and the results of multilevel decomposition and coefficient reconstruction through discrete wavelet transform for May 1, 2019, and the corresponding day in 2020.
From: Impact of open visits on the indoor climate of Mogao Caves
The raw outdoor air temperature signals are displayed in a and l, while the indoor air temperature signals of Cave 71 are shown in b and m. Subsequent panels (c–v) illustrate the results from the 8-level wavelet decomposition of these signals: c and n show the low frequency approximation signals; d through v display the medium-high frequency detail signals, segmented into increasingly shorter periods ranging from 8–4 h to 4–2 min.
