The diurnal surface fluxes-atmosphere relations in Taiwan's montane cloud forests
Abstract
Studies have revealed the impact of atmospheric conditions on the land surface, especially in semi-arid regions, while the surface fluxes can also potentially feedback to the boundary layer development. However, in cool and humid montane cloud forests, land-atmosphere interactions are not thoroughly and widely understood. There are several flux measurement sites in Taiwan's montane cloud forests, which provide an excellent place to explore the interactions between cloud/fog and surface fluxes. Usually, in the afternoon, water vapor brought by mountain wind saturates, thus favoring fog formation. Our study utilized long-term observations from Chi-Lan and Lienhuachih flux towers as well as Community Land Model to analyze the diurnal characteristics of latent heat flux and carbon flux and to further investigate the effects of cloud and fog on surface fluxes. An asymmetric diurnal latent heat flux with an early peak at 9 a.m. was found in Chi-Lan montane cloud forest, while this phenomenon was not found in Lienhuachih station. Results indicate that fog and dew both contribute to the canopy water in Chi-Lan that causes high canopy evaporation after the sunrise, resulting in the asymmetric diurnal latent heat flux. The latent heat flux will decrease when cloud or fog exists due to the lack of incoming solar energy. On the contrary, the carbon flux is not significantly reduced under cloudy conditions. Under the foggy conditions, the carbon flux will also decrease because the fog blocks solar radiation.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.B41L2466G
- Keywords:
-
- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0426 Biosphere/atmosphere interactions;
- BIOGEOSCIENCES;
- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0438 Diel;
- seasonal;
- and annual cycles;
- BIOGEOSCIENCES