It is an important climate parameter and can be used to measure the climate characteristics of a region.
Critical sunshine hours have an important impact on climate and ecological environment. It can control the surface temperature, affect plant growth, change the surface humidity and affect soil erosion.
In addition, the key sunshine time will also affect people's mental health. If the key sunshine time is too short, it will easily lead to psychological depression, anxiety and other symptoms. Therefore, the critical sunshine time is an important climate index, which needs scientific research and management.