2.3 THE ISC LONG‑TERM DRY DEPOSITION MODEL2.3.1

GeneralThe concepts upon which the ISC long‑term dry deposition model are based are discussed in Sections 1.1.6.3 and 1.3.

2.3.2

Point and Volume Source EmissionsThe seasonal deposition at the point located at a particular distance (r) and direction (θ) with respect to the base of a stack or the center of a volume source for particulates in the n

^{th}particle size category is given by:where the vertical term for deposition, V

_{dn}, was defined in Section 1.3.2. K and D are described in Equations (1‑1) and (1‑63), respectively. Q_{τ}is the product of the total time during the l^{th}season, of the seasonal emission rate Q for the i^{th}wind‑speed category, k^{th}stability category. For example, if the emission rate is in grams per second and there are 92 days in the summer season (June, July, and August), Q_{τ,l-3}is given by 7.95 x 10^{6}Q_{l-3}. It should be noted that the user need not vary the emission rate by season or by wind speed and stability. If an annual average emission rate is assumed, Q_{τ}is equal to 3.15 x 10^{7}Q for a 365‑day year. For a plume comprised of N particle size categories, the total seasonal deposition is obtained by summing Equation (2‑7) over the N particle size categories. The program also sums the seasonal deposition values to obtain the annual deposition.2.3.3

Area and Open Pit Source EmissionsThe area and open pit source dry deposition calculations for the ISCLT model are based on the numerical integration algorithm for modeling area sources used by the ISCST model. Section 1.3.3, Equation (1-61), describes the numerical integration for the Short Term model that is applied to specific wind directions by the Long Term model in a trapezoidal integration to calculate the sector average. The process of calculating sector averages for area sources in the Long Term model is described by Equation (2-6) in Section 2.2.3.

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APLICACIONES castellano: DIS CUS DES RAD english: DIS CUS DES RAD

português: DIS CUS DES RAD italiano: DIS CUS DES RAD