F and G needs to be solved

4. Carbon export in upwelling regions. This problem will guide you through the solution of a box model to estimate how much carbon is produced and exported by the biological pump in an upwelfing region similar to the California Current. A schematie of the box model is shown at the end of the homework (Figure 3). Uxe it as your guide. We consider a surface "upwelling box" located next to the coast, which extends for 500 km in the north-south direction, and 50km offshore. That is, the surface area of the upwelling region is 50050km2. The mean upwelling velocity (w) at the base of the box is w=3103m5 1. typical of the California Current (this corresponds to about 950m1 ). The deep water upwelling into the box has a aitrate (NO5) concentration NO3 div =30 mmol m3 and the water in the box has a nitrate concentration NO9=10 mmol m3. (a) Calculate the total transport of water U upwelling into the box, and express your answer in Sverdrups (Sv), a typical ocean transport unit (1Sv=104m3s1). (b) Calculate the residence time of water in the upwelling box (relative to upwelling). assuming that the vertical thickness of the box is 100m. Express your result in units of days. (c) Convince yourself that the conservation equation for nitrate in the box, NO3, wit, is: VdtdNO3surf=UNO3deepU+NO3surfII Where V is the volume of the box (you won't need the actual value). U is the water transpont upwelling into the box and exiting from the offshore side, and is the export of organic nitrogen sinking out of the box by the biolocical pump. Assume seady state and find an expression for the export of organic nitrogen (d) Plug in the numerical values for the upwelling rate U and the nitrate concentrations NOsetp and NOant and determine the value of the organic nitrogen export, expressing it in units of mol 51+ (e) Calculate the residence time of nitrate in the upwelling box (surface), relative to the organic nitrogen export. Express your result in units of days. How does it compare to the residence time of water you found in (b)? (f) Calculate how much organic carbon is exported from the surface box, assuming that it follows a Redfield Ratio (106:16) with organic nitrogen export you found in (d). Express your answer in units of gs1 (a) California's carbon emissions as CO2 to the atmosphere are approximately 120MtC4. where 1Mt=1012g (here only the mass of carbon is considered). How much higher (or lower) would the upwelling rate need to be, so that carbon sequestration by the biological pump in the upwelling region could balance all of California's carbon emissions? Estimate this quantity by taking the ratio of California carbon emission rate to the export of erganic C from that you found in (f)