Factors influencing export of dissolved inorganic nitrogen by major rivers: A new, seasonal, spatially explicit, global model

摘要: Substantial effort has focused on understanding spatial variation in dissolved inorganic nitrogen (DIN) export to the coastal zone and specific basins have been studied depth. Much less is known, however, about seasonal patterns controls of DIN delivery across large scales. Understanding critical efforts predict impacts eutrophication, such as algal blooms hypoxic areas, which are often phenomena. Here we describe, test, apply a global model that predicts regions for >6000 rivers using Nutrient Export from Watersheds (NEWS2) model. NEWS2-DIN-S used spatially explicit, N inputs was calibrated with measured yield (kg N km−2 season−1) 77 rivers, distributed globally. Of characteristics considered, DIN-transport efficiency positively related runoff negatively temperature (r2 = 0.34–0.60, depending season p < 0.0001), likely due flushing effects increased retention by plants soils, respectively. incorporated these insights performed well predicting (Nash-Sutcliffe Efficiency = 0.54–0.65, season). Catchments were effective retaining average rates lower during growing (3–5% total inputs) compared other seasons (6–10%) major latitude bands. Model output insensitive changes magnitude inputs, suggesting refinement input budgets will not substantially improve performance. Rather, better representation land-to-river transfers could future models because strong landscape attenuation.