Observation of SO2 dry deposition velocity at a high elevation flux tower over an evergreen broadleaf forest in Central Taiwan

Dry deposition of nitrogen compounds (NO<sub>2</sub>, HNO<sub>3</sub>, NH<sub>3</sub>), sulfur dioxide and ozone in west and central African ecosystems using the inferential method

“…The V d of O 3 and SO 2 lie well within the range of values determined for other tropical forests (Matsuda et al, 2006, Rummel et al, 2007Tsai et al, 2010) and grasslands (Takahashi et al, 2001;Sorimachi et al, 2003). The modeled V d of NO 2 and NH 3 are within a reasonable range compared to reference values (Zhang et al, 2005Trebs et al, 2006;Kirkman et al, 2002;Delon et al, 2010;Endo et al, 2011).…”

“…In fact, there exists a marked latitudinal gradient over the west and central African zone. Areas with the highest rainfall have the greatest volume of biomass or primary productivity; as a consequence, surface deposition (cuticle) and stomatal uptake become important, and the canopy resistance (R c ) is the main factor determining the deposition rate in vegetative zones (Tsai et al, 2010).…”

“…In addition, V d are higher in the wet season for each ecosystem, especially in dry savannas, where the dry season is well marked. It is considered that higher deposition velocities in the wet season are mainly caused by non-stomatal uptake of wet canopies (Matsuda et al, 2006;Tsai et al, 2010). The interannual variability of V d for the 7 yr period (2002)(2003)(2004)(2005)(2006)(2007) is low and range from 3 to 12 % for NH 3 and SO 2 , from 2 to 11 % for NO 2 and O 3 , and from 2 to 17 % for HNO 3 on the transect of ecosystems.…”

“…In this study, as the cloud cover information was missing, we performed sensitivity tests for the presence of dew by using the constant relative humidity (RH) threshold method for estimating dew condensation (Sentelhas et al, 2008). Various RH thresholds have been used as proxies to determine canopy wetness over forests and grasslands (Tsai et al, 2010;Wichink Kruit et al, 2008Flechard et al, 2011). Thus, we have performed sensitivity tests using a threshold of 90 % for forest, 81 % for wet savanna and 71 % for dry savanna to test the presence of dew.…”

“…Sulfur dioxide (SO 2 ) is one of the important species considering the acid deposition issues, and it is also the precursor of sulfate. Dry deposition estimation of SO 2 is essential to assess ecological impact research, crop growing and air quality research (Tsai et al, 2010). Tropospheric ozone (O 3 ) is known to harm human health, damage vegetation and lead to deterioration of materials.…”