The Long-Term Field Experiment Observatory and Preliminary Analysis of Land-Atmosphere Interaction over Hilly Zone in the Subtropical Monsoon Region of Southern China

To improve current understanding of the water cycle, energy partitioning and CO2 exchange over hilly zone vegetative land surfaces in the subtropical monsoon environment of southern China, a long-term field experiment observatory was set up at Ningxiang, eastern Hunan Province. This paper presents a preliminary analysis of the field observations at the observatory collected from August to November 2012. Results show that significant diurnal variations in soil temperature occur only in shallow soil layers (0.05, 0.10, and 0.20 m), and that heavy rainfall affects soil moisture in the deep layers (>= 0.40 m). During the experimental period, significant diurnal variations in albedo, radiation components, energy components, and CO2 flux were observed, but little seasonal variation. Strong photosynthesis in the vegetation canopy enhanced the CO2 absorption and the latent heat released in daylight hours; Latent heat of evaporation was the main consumer of available energy in late summer. Because the field experiment data are demonstrably reliable, the observatory will provide reliable long-term measurements for future investigations of the land-atmosphere interaction over hilly land surfaces in the subtropical monsoon region of southern China.