Fig. 13: Raw relative humidity data outside and inside Cave 71 on May 1 (left column) and May 6 (right column), 2019, along with the signals after multilevel decomposition and coefficient reconstruction using discrete wavelet transform.
From: Impact of open visits on the indoor climate of Mogao Caves
a and l display the raw outdoor relative humidity signals; b and m depict the raw indoor relative humidity signals of Cave 71. Subsequent panels c–v illustrate the results from the 8-level wavelet decomposition of (b) and (m): c and n present the low frequency approximation signals; d–v detail the medium-high frequency detail signals, with d and o covering the 8–4 h range; e and p the 4–2 h range; f and q the 2–1 h range; g and r the 1–0.5 h range; h and s the 30–15 min range; i and t the 15–8 min range; j and u the 8–4 min range; k and v the 4–2 min range.
