Stream water temperature responses to air temperature and precipitation changes using an elasticity approach in steep forested catchments

We examined stream water temperature variations in response to air temperature and precipitation in 22 steep forested catchments. We conducted an elasticity approach, based on hysteresis loop analysis, stream water temperature, air temperature, and precipitation. Here, hysteresis loops were classified by rising and falling limbs on air temperature. Temporal variations of stream water temperature depended on air temperature rising and falling periods. Based on stream water temperature and both temperature and precipitation elasticities, temperature elasticity increased with increases in stream water temperature during the rising period. However, precipitation elasticity increased with decreases in stream water temperature. The stream water temperature of the steep forested catchments was sensitive to air temperature from an elasticity perspective. Therefore, from an elasticity standpoint, our findings showed that temperature elasticity increased with increasing stream water temperature, whereas precipitation elasticity increased as stream water temperature decreased. Additionally, the variations in stream water temperature were attributed to elasticity responses due to the effect of forested ecosystems and hydrological conditions, even if our study design allowed for the creation of inferences regarding the resilience of forested headwater streams. Further long-term sustainable stream water management plans should be made carefully to include site monitoring for the sensitivity of stream water temperature to environmental factors depending largely on spatial characteristics that had temporal variations.