To estimate the deposition effect of PM2.5 (particle matter with aerodynamic diameter <2.5 µm) in forests in northern China, we used the gradient method to measure the deposition velocity of PM2.5 during the winter and spring above a deciduous forest in Olympic Forest Park and above a coniferous forest in Jiufeng National Forest Park. Six aerosol samplers were placed on two towers at each site at heights of 9, 12 and 15 m above the ground surface. The sample filters were exchanged every four hours at 6∶00 AM, 10∶00 AM, 2∶00 PM, 6∶00 PM, 10∶00 PM, and 2∶00 AM. The daytime and nighttime deposition velocities in Jiufeng Park and Olympic Park were compared in this study. The February deposition velocities in Jiufeng Park were 1.2±1.3 and 0.7±0.7 cm s−1 during the day and night, respectively. The May deposition velocities in Olympic Park were 0.9±0.8 and 0.4±0.5 cm s−1 during the day and night, respectively. The May deposition velocities in Jiufeng Park were 1.1±1.2 and 0.6±0.5 cm s−1 during the day and night, respectively. The deposition velocities above Jiufeng National Forest Park were higher than those above Olympic Forest Park. The measured values were smaller than the simulated values obtained by the Ruijgrok et al. (1997) and Wesely et al. (1985) models. However, the reproducibility of the Ruijgrok et al. (1997) model was better than that of the Wesely et al. (1985) model. The Hicks et al. (1977) model was used to analyze additional forest parameters to calculate the PM2.5 deposition, which could better reflect the role of the forest in PM2.5 deposition.

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During the period From November 1998 to October 1999, the air sulfur dioxide (SO2) and sulfate (SO2−4) concentrations were measured and rain water was collected on farmland at Yingtan, a typical red soil area in the Jiangxi province of China. Based on hourly meteorological data and surface resistance data from the literature, the dry deposition velocities of SO2 and SO2−4 were computed using a three‐layer resistance analogy model, and sulfur dry deposition was calculated. The wet deposition was obtained from precipitation amount and sulfur concentrations in rainwater. The average dry deposition velocities of SO2 and SO2−4 on farmland were found to be 0.38 ± 0.16 cm s−1 (monthly average 0.16–0.55 cm s−1) and 0.20 ± 0.12 cm s−1 (monthly average 0.15–0.27 cm s−1), respectively. The annual total sulfur deposition for the study region is about 103 kg S ha−1, of which 83% is dry deposition. The uncertainties due to measurement and the dry deposition model are less than 30%. It is also found that atmospheric deposition plays a key role in sulfur circulation within the agrecosystem, accounting for more than 90% of the total sulfur input to farmland

The relationships between soil respiration and environmental factors determine the effect of warming soil on the carbon balance in temperate forest ecosystems and on changes in atmospheric CO2 concentrations. Here, we used 3 years of data regarding soil respiration rates (Rs), soil temperature (Ts), and soil volumetric water content (θ) from a 50-year-old mature cedar ( Platycladus orientalis L.) plantation at Jiufeng Mountain, Beijing, China, to demonstrate the seasonal and interannual variation of Rs dependence on Ts and θ throughout the period 2008–2010. We used the exponential model to calculate the temperature sensitivity indicator Q10 and we examined the annual and seasonal patterns of Rs and Q10. The Rs correlated with Ts annually (p < 0.05). The Rs–Ts exponential relationship was significant in the autumn and winter (p < 0.05), while the combined Ts and θ relationships with Rs were significant in the spring and summer (p < 0.001). The spring Rs anomalies caused by drought appeared to have carryover effects that translated to Rs anomalies in the following summer. Finally, the summer Rs, which was influenced by the coincident precipitation and θ anomalies, determined the magnitude of the annual total amount of soil respiration. This result has implications for how abiotic factors may drive shifts in seasonal patterns of soil respiration under a changing climate.

Tibetan Plateau (TP), as the "third pole" of world, has experienced significant and rapid warming over the past several decades with a warming rate of about twice the global rate (Chen et al., 2015), even during the period of the global hiatus (Duan & Xiao, 2015;You et al., 2016). Such rapid warming has caused glacier retreat and permafrost degradation (Bibi et al., 2018;Yao et al., 2019) and has been proved to be partly related to the changes of cloud properties (e.g., reduced total and low cloud covers during daytime allowed more solar radiation to reach the surface) (