Discontinuity of Diurnal Temperature Range Along Elevated Regions

Low-clouds and fog moderate the diurnal temperature range (DTR) through radiative effects. Consequently, frequent foggy events make montane cloud forests (MCFs) stable and unique. However, high-resolution observations in the forest understory are rare. To investigate the DTR variation in elevations, we surveyed the Central Cross-Island Highway in central Taiwan along the altitude of 0–3,000 m across both the non-cloud forest and MCFs. The results from paired weather stations revealed that the DTR increases significantly with altitude in open fields but not in the forest's understory. Furthermore, the continuous observations in altitude indicate that smaller DTRs were found in both open field and understory sites in the MCF compared with those in low- and high-altitude sites. The DTR discontinuity highlights the indispensability of MCF for the mountain ecosystem. Further simulating the integrative effect of the climate and land-use change on fog is crucial for the ecoclimate in mountainous regions.