Hi everyone! I have run a BSSP370cmip6 compost case to conduct local iron fertilization simulation in CESM2.1.3.
However, the surface iron concentration had a significant decrease somewhere (for example, the North Pacific, the mid-Atlantic) when I did iron fertilization simulation in the Southern Ocean by increasing the iron fraction in the atmospheric coarse and fine dust and black carbon flux here. Based on my current understanding, the iron concentration outside the fertilization area should increase relative to the control run (due to iron from fertilized area by ocean currents advection). This change pattern confused me a lot, which made me uncertain whether I made correct modifications.
At first, I thought the decrease in iron concentration might be the calculation error in atm coarse/fine dust or black carbon flux, since these fluxes are passed dynamically from the coupler. But the same decrease also occurred when I doubled iron flux from sediment or river files. So I wonder if there are seesaw effects in the CESM iron cycle. For example, when I increased atm iron input in the Southern Ocean (or somewhere), the atm iron input decreased in other areas to make total iron flux steady. I also tried to explain the decrease from Fe scavenge and biological uptake, but it didn't seem to work. I also tried to explain this from the intensified stratification, but I only run 2 years and take the final year average for results analysis. I thought 2 years is too short to see climate change influences. Maybe I should run a longer simulation to allow the ocean system sufficient time to respond to local iron fertilization?
Thank you sincerely for your time and any suggestions!
However, the surface iron concentration had a significant decrease somewhere (for example, the North Pacific, the mid-Atlantic) when I did iron fertilization simulation in the Southern Ocean by increasing the iron fraction in the atmospheric coarse and fine dust and black carbon flux here. Based on my current understanding, the iron concentration outside the fertilization area should increase relative to the control run (due to iron from fertilized area by ocean currents advection). This change pattern confused me a lot, which made me uncertain whether I made correct modifications.
At first, I thought the decrease in iron concentration might be the calculation error in atm coarse/fine dust or black carbon flux, since these fluxes are passed dynamically from the coupler. But the same decrease also occurred when I doubled iron flux from sediment or river files. So I wonder if there are seesaw effects in the CESM iron cycle. For example, when I increased atm iron input in the Southern Ocean (or somewhere), the atm iron input decreased in other areas to make total iron flux steady. I also tried to explain the decrease from Fe scavenge and biological uptake, but it didn't seem to work. I also tried to explain this from the intensified stratification, but I only run 2 years and take the final year average for results analysis. I thought 2 years is too short to see climate change influences. Maybe I should run a longer simulation to allow the ocean system sufficient time to respond to local iron fertilization?
Thank you sincerely for your time and any suggestions!