clarify units for mass

[mnlevy1981]

@rmshkv was trying to understand the units we use for mass, and digging through the code it's unclear. She was asking about fish yield units, and I tried (unsuccessfully) to trace it through the code. I did notice that, on the forcing side, the zooplankton biomass is called zooC but it's actually the zooplankton wet weight per area (in grams per square meter):

        # Conversion from Colleen:
        # 1e9 nmol in 1 mol C
        # 1e4 cm2 in 1 m2
        # 12.01 g C in 1 mol C
        # 1 g dry W in 9 g wet W (Pauly & Christiansen)
        nmol_cm2_TO_g_m2 = 1e-9 * 1e4 * 12.01 * 9.0

with

        forcing_ds['zooC'].data = forcing_ds['zooC'].data * nmol_cm2_TO_g_m2

[Also, why are we using grams and meters rather than grams and centimeters (cgs) or kilograms and meters (mks)?]

[cpetrik]

Hi Mike and Elena, The native units in FEISTY are grams wet weight per m2 (per day if a rate). Thus, all ESM forcing variables are converted into those units. The fishing yield output is gWW/m2/d. If you want to calculate annual fishing yield, you just multiply by the grid cell area and 365.

…

On Tue, Aug 15, 2023 at 12:43 PM Michael Levy ***@***.***> wrote: @rmshkv <https://github.com/rmshkv> was trying to understand the units we use for mass, and digging through the code it's unclear. She was asking about fish yield units, and I tried (unsuccessfully) to trace it through the code. I did notice that, on the forcing side, the zooplankton biomass is called zooC but it's actually the zooplankton wet weight per area (in grams per square meter): # Conversion from Colleen: # 1e9 nmol in 1 mol C # 1e4 cm2 in 1 m2 # 12.01 g C in 1 mol C # 1 g dry W in 9 g wet W (Pauly & Christiansen) nmol_cm2_TO_g_m2 = 1e-9 * 1e4 * 12.01 * 9.0 with forcing_ds['zooC'].data = forcing_ds['zooC'].data * nmol_cm2_TO_g_m2 [Also, why are we using grams and meters rather than grams and centimeters (cgs) or kilograms and meters (mks)?] — Reply to this email directly, view it on GitHub <#54>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AA5AFXJDVRZXHJN4RQYPNN3XVPGNPANCNFSM6AAAAAA3RP7WPM> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>