Figure 1.
Location of Adirondack Park in New York State and the elevation (unit: m) distribution in the Park (upper panel), and the land cover distribution pattern of the Park (lower panel).
The location of the Huntington Wildlife Forest is represented by the star. In this paper, we used the same color scheme to represent the LUCs in all the figures.
Figure 2.
Daily average seasonal meteorological conditions at Huntington Wildlife Forest for the period 2009–2011 measured by CASTNET.
Temperature and wind speed exhibited much diurnal variations. However their annual patterns followed the same patterns presented here. Precipitation and snow were mainly event-based. The area between the gray vertical dashed lines represent the leaf-on period.
Figure 3.
Atmospheric Hg deposition modeling scheme used in this study.
Wet Hg deposition is considered as precipitation Hg deposition, while dry Hg deposition is considered as the sum of modeled dry deposition to the non-forested areas and deciduous forest in the leaf-off period, and litterfall and net throughfall (throughfall minus precipitation deposition) Hg deposition to the coniferous forest and deciduous forest in the leaf-on period.
Figure 4.
Measured diurnal and seasonal atmospheric Hg concentrations (mean 95% confidence value) from 2009–2011 at the Huntington Wildlife Forest in the Adirondack Park.
GOM, gaseous oxidized Hg; PBM, particulate bound Hg; GEM, gaseous elemental Hg. Units for GOM and PBM are pg m, and for GEM is ng m
.
Figure 5.
Box plots of deposition velocities (cm s) for the major land use categories (LUCs) in the Adirondacks.
The upper and lower bars represent the 5th and 95th percentile values, respectively; the bars represent the median (red bars) and mean (white bars) values.
Figure 6.
The cumulative and seasonal patterns of annual dry Hg deposition (left panel; GEM left axis, GOM and PBM right axis), and annual dry Hg deposition patterns of the three forms of atmospheric Hg to water, coniferous and deciduous forests in the Adirondacks (right panel).
Figure 7.
Spatial distribution patterns of atmospheric Hg deposition (unit:g m
yr
to the Adirondack Park, including: a) wet deposition, b) litterfall deposition (LF), c) surface GEM evasion, d) throughfall deposition (TF), e) the sum of LF and net TF (TF - wet deposition), f) the modeled dry deposition (sum of GEM, GOM and PBM deposition), and g) the total net Hg deposition (wet+dry - evasion).
Figure 8.
Plot a): Relationships of modeled Hg dry deposition fluxes with elevation (GEM left axis, GOM and PBM right axis).
The logistic equations used are shown in SI Table A. Plot b): The effect of the scaling factor () on the modeled dry Hg deposition, and the comparisons with field data (solid lines: modeled dry deposition; while the dotted, dashed, and dash-dotted lines: the field data of litterfall Hg deposition and the sum of litterfall (LF) and net throughfall (TF) Hg deposition, respectively). Note that the net throughfall Hg for deciduous forest is small, with the values for LF Hg deposition and the sum of LF and TF Hg deposition as 14.7
g m
yr
and 14.9
g m
yr
, respectively. In this study, we used a value of 0.1, and the corresponding modeled dry Hg deposition to coniferous (dark green triangle symbol) and deciduous (blue triangle symbol) forests were: 17.5
g m
yr
and 12.4
g m
yr
, respectively. The blue circle that nearly supersedes the dark green triangle represents the modeled net dry Hg deposition to deciduous forest (17.9
g m
yr
).