Figure 1.
(A) Overview of the multi-scale modeling framework; DIN, DON, DIP, and DOP in the box refer to dissolved inorganic (DIN, DIP) and dissolved organic (DON, DOP) nitrogen and phosphorus. (B) Illustrations of polygon-based units as the intermediate modeling scale. (C) Illustrations of the multi-scale framework: from polygon units to different biophysical and administrative scales. *This box also includes manure application on land, biological N2 fixation, atmospheric N deposition, crop export, and human waste applied on land from people that are not connected to sewage systems. **Others include human waste from unconnected populations that are directly discharged to water bodies. ***For a complete overview of inputs and sources see section S1 and Tables S1,S2.