Figure 8. Energetics model of Hillsborough County natural system illustrating 

 the translation of the model into differential equation form. 



N = (k.-kpJJ N-k-N-k.N = differential equation for N 



where 



E = 



N = 



J = 



J = 







J = 







.'.J 



N = 



Energy source (solar, rain, and wind) 



natural biomass 



energy flow coefficients 



inflow of energy (solar insolation) 



energy not used (albedo) 



energy absorbed by system (absorbed insolation) 



J + J = conservation of energy 

 r ^"^ 



k J N 

 r 



J + k NJ 

 r or 



(k^Mc^) jf^=. N_. f^ 

 1+k N 3 4 







319 



