Changes between Version 13 and Version 14 of CarbonCycleUnits

Timestamp:

12/01/17 12:52:01 (6 years ago)

Author:

smoreira

Comment:

--

CarbonCycleUnits

@@ -55 +55 @@
 
 Lines 410 to 425 show the calculations of the DIC, OC13 and OC14 dynamics. In line 421, we can observe how ODIC is calculated using variable '''vdic''', which includes PHYTO_dif, ZOO_dif, TPP_dif, ODOC_dif and ODOCS_dif.
-[[BR]]
+[[BR]] 
 From the previous analysis of Six and Maier-Reimer (1996) and its equivalences in OCYCC, we have concluded that all those variables are expressed in µmol×kg^-1^, or equivalently in µmol×L^-1^. It is precisely in line 421, where ODIC is calculated, where variable vdic (µmol×kg^-1^) is multiplied by the '''SCANU''' factor equal to 1.0e^-06^. This is precisely the conversion factor, 1 µmol = 10^-6^ mol.
 
 === out_ocycc.f & eco2.f, scale_m factor ===
+
+The output file '''C_reservoirs.txt''' contains some values related to total carbon content in the ocean, atmosphere and vegetation and looking into the values of '''OC_C''' around 39000 coincides with the accepted value of GtC ("gigatons of carbon") of total carbon in the ocean. Calues in this file are written in line 340 of '''out_cycc.f''' and they are calculated in file '''eco2.f'''.
+[[BR]]
+In lines 96 and 230 of eco2.f, initial total carbon inthe ocean is calculated using the following expression: 
+[[BR]]
+ca_oc = ca_oc + (PHYTO_M(i,J,n) + ZOO_M(i,J,n) + ODOC(i,J,n) + OPOC(i,J,n) + ODOCS(i,J,n) + ODIC(i,J,n)*1e06) * fhypt(j) * DVOL(i,J,n) *12 * SCALE_M * 1.028
+[[BR]]
+
+Here we can see that ODIC values are multiplied by 1.0e06, which confirms that phytoplankton, zooplankton and organic carbon are expressed in µmol×kg^-1^ and ODIC is expressed in mol×kg^-1^
+
+Let's have a look more in detail to this equation. The first part of the equation, expressed in µmol×kg^-1^, is turned into µmol×L^-1^ when we multiply by a density value of 1.028 kg/L. Then, it is necessary to multply by 10^3^ to convert the volume of the ocean layer from m^3^ to L. Next step is multiplying by a factor of 10^-6^ to convert µmol into mol before multiplying by the atomic weight of carbon, 12 g/mol to get the total mass in grams. The final step would be multiplying by a factor of 10^-15^ to convert from g to Gt of carbon.
+[[BR]]
+
+This combination of 10^3^x 10^-6^x 10^-15^ turns to be exactly the value of SCALE_M, 1.0e-018.
+
 === out_ocycc.f & eco2.f, scale_b factor ===