Units
has_units holds UCUM (issues
#14 and
#88). BERVO does not define its own
unit terms, and does not map units to a unit ontology such as UO, which cannot carry
the detail these variables need: which element a mass is of, and whether a value is a
total for a grid cell. The rules for writing a unit are in the has_units section of
AGENTS.md. This page records the conversion.
The decisions
| Question | Decision |
|---|---|
EcoSIM's d-2 |
A trailing /{grid}. In EcoSIM it marks a total for a grid cell, and in UCUM d is the day. |
A substance inside a unit (gC, m3 H2O) |
A UCUM annotation on the unit it qualifies: g{C}, m3{H2O}. |
NONE |
UCUM's unity, 1. NA stays for a variable with no numeric magnitude. |
| Syntax | Exponents joined by .. Once a / appears, no . follows it outside parentheses. |
| A duration in years | a, UCUM's Julian year of 365.25 days. Not yr, which is not UCUM, and not 365.d. First used on Time since fire and Fire return interval (issue #134). |
| A duration in months | mo, UCUM's mean Julian month of 30.4375 days, where the source reports months, as TRY does for leaf lifespan. Use a for years and d for days, and keep the source's unit rather than converting. First used on Leaf lifespan (issue #27). |
| An exchange capacity | Moles of charge, UCUM's eq: ceq.kg-1 for cmol(+)/kg. Not cmol, which is an amount of substance. See Charge equivalents (issue #119). |
What d-2 means
EcoSIM builds its d-2 quantities from grid-cell totals. VGeomLayer_vr, declared
[m3 d-2], is set as AREA_3D(3,L,NY,NX)*DLYR_3D(3,L,NY,NX) in StartsMod.F90: the
layer's ground area times its thickness, the volume of the whole cell. EcoSIM's own
AGENTS.md tells its developers to keep "per-area values" apart from "grid-cell
totals". So g d-2 is grams in the grid cell, written here as g/{grid}. {grid} is
unity to a converter, so the dimension is mass, as a total should be.
This reading comes from the code, not from an EcoSIM statement of the convention. If a
d-2 variable turns out to be normalised per square metre, its unit becomes .m-2.
d-3 appears once, on Root autotrophic respiration (BERVO:0000434), and is
treated the same way, since each layer is its own grid cell. t-1 is per time step,
written /{step}, and p-1 is per plant, written /{plant}.
Mapping
All 235 strings that were in the column, with the number of rows each was on.
1572 of the 2707 filled cells changed in the conversion, and three more (the MPa log
rows, see Logarithms) after review: 1575 in all. A note marks a typo fixed on the
way (the row's meaning was clear) or a meaning that looks wrong (converted as written,
and left for a curator).
| Was | UCUM | Rows | Note |
|---|---|---|---|
NA |
NA |
951 | |
NONE |
1 |
222 | two categorical rows, BERVO:0000826 and BERVO:0001740, became NA after review (#108) |
g d-2 |
g/{grid} |
174 | three Log … rows became 1 after review; see Logarithms |
g d-2 h-1 |
g.h-1/{grid} |
171 | |
m |
m |
87 | |
g m-3 |
g.m-3 |
66 | |
m3 d-2 |
m3/{grid} |
52 | |
mol m^-3 |
mol.m-3 |
52 | |
m2 h-1 |
m2.h-1 |
51 | |
g g-1 |
g.g-1 |
50 | |
m3 d-2 h-1 |
m3.h-1/{grid} |
43 | |
MJ d-2 h-1 |
MJ.h-1/{grid} |
35 | |
h-1 |
h-1 |
31 | |
mol d-2 h-1 |
mol.h-1/{grid} |
26 | |
m2 d-2 |
m2/{grid} |
21 | |
m3 m-3 |
m3.m-3 |
19 | |
h |
h |
18 | |
oC |
Cel |
15 | |
mol^2 m^-6 |
mol2.m-6 |
14 | |
gC d-2 h-1 |
g{C}.h-1/{grid} |
13 | |
m3 H2O d-2 h-1 |
m3{H2O}.h-1/{grid} |
13 | |
m^3 mol^-1 |
m3.mol-1 |
13 | |
MPa |
MPa |
12 | three Log … rows became 1 after review; see Logarithms |
gC d-2 |
g{C}/{grid} |
12 | |
mol^3 m^-9 |
mol3.m-9 |
12 | |
umol m-2 s-1 |
umol.m-2.s-1 |
12 | |
Mpa |
MPa |
11 | typo: Mpa is not a unit; megapascal is MPa |
kJ g-1 C |
kJ.g-1{C} |
11 | |
C |
Cel |
10 | suspect: most of these rows are functions, factors or element masses, not temperatures |
K |
K |
10 | |
MJ d-2 |
MJ/{grid} |
10 | |
mol d-2 |
mol/{grid} |
10 | |
mol m-3 |
mol.m-3 |
10 | |
uM |
umol.L-1 |
10 | |
g solute /g gas |
g{solute}.g-1{gas} |
9 | |
umol mol-1 |
umol.mol-1 |
9 | |
d-2 |
/{grid} |
8 | |
g C m-3 |
g{C}.m-3 |
8 | |
g N m-3 |
g{N}.m-3 |
8 | |
MJ d-2 t-1 |
MJ/{grid}/{step} |
7 | suspect: several rows are water transfers, not energy |
g/d2/h |
g.h-1/{grid} |
7 | |
gN d-2 h-1 |
g{N}.h-1/{grid} |
7 | |
ppmv |
[ppm]{vol} |
7 | |
MJ d-2 K-1 |
MJ.K-1/{grid} |
6 | |
degree |
deg |
6 | |
h^-1 |
h-1 |
6 | |
kPa |
kPa |
6 | |
oC\|K |
Cel\|K |
6 | |
MJ m-2 h-1 |
MJ.m-2.h-1 |
5 | |
Mg d-2 |
Mg/{grid} |
5 | |
Mg d-2 h-1 |
Mg.h-1/{grid} |
5 | |
g m-2 |
g.m-2 |
5 | |
gN gC-1 |
g{N}.g-1{C} |
5 | |
gN m-3 |
g{N}.m-3 |
5 | |
m2 m-2 |
m2.m-2 |
5 | |
m3 d-2 t-1 |
m3/{grid}/{step} |
5 | |
mm h-1 |
mm.h-1 |
5 | |
Mg m-3 |
Mg.m-3 |
4 | |
g C g-1 N h-1 |
g{C}.g-1{N}.h-1 |
4 | |
g/mol |
g.mol-1 |
4 | |
gP d-2 h-1 |
g{P}.h-1/{grid} |
4 | |
m d-2 |
m/{grid} |
4 | suspect: a length per grid cell; the root length rows may mean m, the conductance row m.h-1 |
m g-1 |
m.g-1 |
4 | |
m2 |
m2 |
4 | |
m3 H2O d-2 |
m3{H2O}/{grid} |
4 | |
m^6 mol^-2 |
m6.mol-2 |
4 | |
mg P kg-1 |
mg{P}.kg-1 |
4 | |
mg kg-1 |
mg.kg-1 |
4 | |
mm d-1 |
mm.d-1 |
4 | |
umol g-1 h-1 |
umol.g-1.h-1 |
4 | |
0-1 |
1 |
3 | |
MJ d-2 t-1\|W m-2 |
MJ/{grid}/{step}\|W.m-2 |
3 | |
MJ/K |
MJ.K-1 |
3 | |
W m-2 |
W.m-2 |
3 | |
g C g-1C h-1 |
g{C}.g-1{C}.h-1 |
3 | |
g kg-1 |
g.kg-1 |
3 | |
g m-2 h-1 |
g.m-2.h-1 |
3 | |
g/m2/hr |
g.m-2.h-1 |
3 | |
gC |
g{C} |
3 | |
gP gC-1 |
g{P}.g-1{C} |
3 | |
kJ/kg |
kJ.kg-1 |
3 | |
kg Mg-1 |
kg.Mg-1 |
3 | |
m MPa-1 h-1 |
m.MPa-1.h-1 |
3 | |
m h-1 |
m.h-1 |
3 | |
m2 d-2 h-1 |
m2.h-1/{grid} |
3 | |
m3 d-2 h-1\|m s-1 |
m3.h-1/{grid}\|m.s-1 |
3 | |
mg Ca kg-1 |
mg{Ca}.kg-1 |
3 | |
s m-1 |
s.m-1 |
3 | |
umol m-3 |
umol.m-3 |
3 | |
MJ h-1 |
MJ.h-1 |
2 | |
MJ m-1 |
MJ.m-1 |
2 | |
MJ/d2/h |
MJ.h-1/{grid} |
2 | |
MJ/m3/K |
MJ.m-3.K-1 |
2 | |
MPa h m-2 |
MPa.h.m-2 |
2 | |
Pa |
Pa |
2 | |
cmol kg-1 |
cmol.kg-1 |
2 | both became ceq.kg-1 (#119) |
degrees from horizontal |
deg |
2 | |
g |
g |
2 | |
g g-1C h-1 |
g.g-1{C}.h-1 |
2 | |
g g-1C h-1 |
g.g-1{C}.h-1 |
2 | |
g H m-3 |
g{H}.m-3 |
2 | |
g N m-2 h-1 |
g{N}.m-2.h-1 |
2 | |
g P m-3 |
g{P}.m-3 |
2 | |
g m^-3 |
g.m-3 |
2 | |
g micr C g-1 subs C |
g{C_microbial}.g-1{C_substrate} |
2 | |
g subs. C g-1 micr. C |
g{C_substrate}.g-1{C_microbial} |
2 | |
gC d2 h-1 |
g{C}.h-1/{grid} |
2 | typo: d2 was missing its minus sign |
gC gC-1 |
g{C}.g-1{C} |
2 | |
gO d-2 h-1 |
g{O}.h-1/{grid} |
2 | |
h m-1 |
h.m-1 |
2 | |
kJ g-1 N |
kJ.g-1{N} |
2 | |
kg m-2 |
kg.m-2 |
2 | |
m d-1 |
m.d-1 |
2 | |
m d-2 h-1 |
m.h-1/{grid} |
2 | |
m m-3 |
m.m-3 |
2 | |
m p-1 |
m/{plant} |
2 | |
m t-1 |
m/{step} |
2 | |
m-1 |
m-1 |
2 | |
m-2 |
m-2 |
2 | |
m3 H2O (gC)-1 |
m3{H2O}.g-1{C} |
2 | |
mg Al kg-1 |
mg{Al}.kg-1 |
2 | |
mg Fe kg-1 |
mg{Fe}.kg-1 |
2 | |
mm |
mm |
2 | |
mol N m-3 |
mol{N}.m-3 |
2 | |
mol m-2 |
mol.m-2 |
2 | |
mol^4 m^-12 |
mol4.m-12 |
2 | |
uM /umol mol-1 |
umol.L-1/(umol.mol-1) |
2 | |
umol e- umol CO2 |
umol{e-}.umol-1{CO2} |
2 | typo: the CO2 denominator was missing its -1 |
umol umol-1 |
umol.umol-1 |
2 | |
J (mole K)^-1 |
J.mol-1.K-1 |
1 | |
J m-2 |
J.m-2 |
1 | |
J/g/K~MJ/m3/K |
J.g-1.K-1\|MJ.m-3.K-1 |
1 | |
MJ d-2 |
MJ/{grid} |
1 | |
MJ d-2 h-1 |
MJ.h-1/{grid} |
1 | |
MJ K-1 |
MJ.K-1 |
1 | |
MJ d-1 |
MJ.d-1 |
1 | |
MJ d-2 h-1\|W m-2\|MW m-2 |
MJ.h-1/{grid}\|W.m-2\|MW.m-2 |
1 | |
MJ k-1 d-2 |
MJ.K-1/{grid} |
1 | typo: k-1 for K-1 |
MJ m h-1 K-1 |
MJ.m.h-1.K-1 |
1 | |
MJ m-1 h-1 K-1 |
MJ.m-1.h-1.K-1 |
1 | |
MJ m-2 d-1 |
MJ.m-2.d-1 |
1 | |
MJ m-3 |
MJ.m-3 |
1 | suspect: a heat flux in MJ m-3 |
MJ/K d-2 |
MJ.K-1/{grid} |
1 | |
MJ/K/gC |
MJ.K-1.g-1{C} |
1 | |
MJ/h |
MJ.h-1 |
1 | |
MJ/h\|MJ m-2 h-1\|W m-2 |
MJ.h-1\|MJ.m-2.h-1\|W.m-2 |
1 | |
MPa h m-4 |
MPa.h.m-4 |
1 | |
MPa\|Pa |
MPa\|Pa |
1 | |
Mg d-2 t-1 |
Mg/{grid}/{step} |
1 | |
Mg m-1 s |
Mg.m-1.s-1 |
1 | typo: a viscosity is Mg m-1 s-1; EcoSIM declares VISCW = 1.0E-06 [Mg m-1 s], which is 1 mPa s only with s-1 |
Mg m-3\|kg m-3 |
Mg.m-3\|kg.m-3 |
1 | |
Mg soil/gC |
Mg{soil}.g-1{C} |
1 | |
MgC m-3 |
Mg{C}.m-3 |
1 | |
W m-1 K-1 |
W.m-1.K-1 |
1 | |
cm |
cm |
1 | |
cm\|m |
cm\|m |
1 | |
dS m-1 |
dS.m-1 |
1 | |
degrees north |
deg |
1 | |
eqv (gC)^-1 |
eq.g-1{C} |
1 | |
g /d2 |
g/{grid} |
1 | |
g C g-1 C |
g{C}.g-1{C} |
1 | |
g C g-1 soil |
g{C}.g-1{soil} |
1 | |
g C m-2 |
g{C}.m-2 |
1 | |
g H2O g-1 C |
g{H2O}.g-1{C} |
1 | |
g J-1 |
g.J-1 |
1 | |
g Mg-1 |
g.Mg-1 |
1 | |
g Mg-1\|g g-1 |
g.Mg-1\|g.g-1 |
1 | |
g N g-1 C |
g{N}.g-1{C} |
1 | |
g N, g-1 C |
g{N}.g-1{C} |
1 | |
g O m-3 |
g{O}.m-3 |
1 | |
g P g-1 C |
g{P}.g-1{C} |
1 | |
g P m-2 h-1 |
g{P}.m-2.h-1 |
1 | |
g cm-3 |
g.cm-3 |
1 | |
g d-2 t-1 |
g/{grid}/{step} |
1 | |
g g-1 h-1 |
g.g-1.h-1 |
1 | |
g gC-1 |
g.g-1{C} |
1 | |
g h-1 |
g.h-1 |
1 | |
g m-3\|umol mol-1 |
g.m-3\|umol.mol-1 |
1 | |
g p-1 |
g/{plant} |
1 | |
g/cm3~ton/m3 |
g.cm-3\|t.m-3 |
1 | |
g/d2 |
g/{grid} |
1 | |
gC d-2 hr-1 |
g{C}.h-1/{grid} |
1 | |
gC d-3 hr-1 |
g{C}.h-1/{grid} |
1 | suspect: EcoSIM declares d-3, a per-volume grid measure; still a total per grid cell |
gC m-3 |
g{C}.m-3 |
1 | |
gC/d2/hr |
g{C}.h-1/{grid} |
1 | |
gC/h |
g{C}.h-1 |
1 | |
gN |
g{N} |
1 | |
gN d-2 |
g{N}/{grid} |
1 | |
gO m-3 |
g{O}.m-3 |
1 | |
gP |
g{P} |
1 | |
gP d-2 |
g{P}/{grid} |
1 | |
ha-1\|m-2 |
har-1\|m-2 |
1 | |
kPa\|Pa |
kPa\|Pa |
1 | |
kg m-3 |
kg.m-3 |
1 | |
m h-1\|h m-1 |
m.h-1\|h.m-1 |
1 | |
m h-1\|m s-1 |
m.h-1\|m.s-1 |
1 | |
m s-1 |
m.s-1 |
1 | |
m2 g-1 |
m2.g-1 |
1 | |
m2 ha-1 |
m2.har-1 |
1 | |
m2 m-3 |
m2.m-3 |
1 | |
m3 |
m3 |
1 | |
m3 H2O/d2/h |
m3{H2O}.h-1/{grid} |
1 | |
m3 H3O d-2 h-1 |
m3{H2O}.h-1/{grid} |
1 | typo: H3O for H2O |
m3 d-2 h-1\|m SWE s-1 |
m3.h-1/{grid}\|m{SWE}.s-1 |
1 | |
m3 g-1 |
m3.g-1 |
1 | |
m3 gC-1 |
m3.g-1{C} |
1 | |
m3 pore m-3 litr |
m3{pore}.m-3{litter} |
1 | |
m3 s-1 |
m3.s-1 |
1 | |
m^9 mol^-3 |
m9.mol-3 |
1 | |
mg C kg-1 |
mg{C}.kg-1 |
1 | |
mg CaCO3 kg-1 pH-1 |
mg{CaCO3}.kg-1/{pH} |
1 | |
mg Cl kg-1 |
mg{Cl}.kg-1 |
1 | |
mg K kg-1 |
mg{K}.kg-1 |
1 | |
mg Mg kg-1 |
mg{Mg}.kg-1 |
1 | |
mg Mn kg-1 |
mg{Mn}.kg-1 |
1 | |
mg N kg-1 |
mg{N}.kg-1 |
1 | |
mg Na kg-1 |
mg{Na}.kg-1 |
1 | |
mg S kg-1 |
mg{S}.kg-1 |
1 | |
mg Zn kg-1 |
mg{Zn}.kg-1 |
1 | |
mol h-1 |
mol.h-1 |
1 | |
mol m^-^3 |
mol.m-3 |
1 | typo: stray caret |
mol/d2/h |
mol.h-1/{grid} |
1 | |
mol^11 m^-33 |
mol11.m-33 |
1 | |
mol^11 mol^-33 |
mol11.m-33 |
1 | typo: mol^-33 for m^-33, as its sibling SYCAH1 has |
mol^8 m^-24 |
mol8.m-24 |
1 | |
n m-3 |
{cells}.m-3 |
1 | |
nephelometric turbidity units |
{NTU} |
1 | |
oC-1 |
K-1 |
1 | a Celsius degree cannot take an exponent in UCUM; per degree Celsius is per kelvin |
s |
s |
1 | |
s h-1 |
s.h-1 |
1 | |
s m-1\|s h-1 |
s.m-1\|s.h-1 |
1 | |
s/day |
s.d-1 |
1 | |
s/hour |
s.h-1 |
1 | |
umol e- umol-1 PAR |
umol{e-}.umol-1{PAR} |
1 | |
umol mol-1\|gC m-3 |
umol.mol-1\|g{C}.m-3 |
1 |
Logarithms
A logarithm has no unit, whatever the unit of the value it was taken of. Six Log …
rows carried the unit of that value, g d-2 or MPa, and now take 1, as Log soil
porosity (BERVO:0001508, NONE on main) does after the conversion: BERVO:0001509, BERVO:0001510,
BERVO:0001511, BERVO:0001516, BERVO:0001517, BERVO:0001518. This settles the
log rows of issue #95. Its question
about the two volumetric water contents is still open.
Suspect meanings
These were converted faithfully and are listed so a curator can check the rows. The validator cannot see any of them, because each is valid UCUM.
m d-2on 4 rows (BERVO:0000354,BERVO:0001101,BERVO:0001102,BERVO:0001452): a length per grid cell; the root length rows may mean m, the conductance row m.h-1.gC d-3 hr-1on 1 row (BERVO:0000434): EcoSIM declares d-3, a per-volume grid measure; still a total per grid cell.MJ d-2 t-1on 7 rows (BERVO:0000580,BERVO:0000581,BERVO:0001146,BERVO:0001150,BERVO:0001442,BERVO:0001446,BERVO:0001447): several rows are water transfers, not energy.Con 10 rows (BERVO:0000760,BERVO:0000885,BERVO:0000926,BERVO:0001074,BERVO:0001353,BERVO:0001354,BERVO:0001362,BERVO:0001363,BERVO:0001435,BERVO:0001653): most of these rows are functions, factors or element masses, not temperatures.MJ m-3on 1 row (BERVO:0001489): a heat flux in MJ m-3.
pH as an annotation
Soil lime buffer capacity (BERVO:0001904) is mg{CaCO3}.kg-1/{pH}, with pH as an
annotation. UCUM has [pH], but it is a special unit, and UCUM does not let a special unit be
combined with other units in a term. The annotation keeps the meaning in the string without
breaking that rule.
Charge equivalents
Exchange capacities are reported in centimoles of charge per kilogram, cmol(+)/kg,
the same number as meq/100 g. UCUM writes a mole of charge as eq, so the unit is
ceq.kg-1. cmol.kg-1 is an amount of substance, and for a divalent ion such as Ca2+ one
mole is two moles of charge, so the two readings differ by the ion's valence (issue
#119).
These rows take ceq.kg-1: Soil cation exchange capacity (BERVO:0000883), Soil anion
exchange capacity (BERVO:0000884), Soil exchangeable acidity (BERVO:0002024), Soil
effective cation exchange capacity (BERVO:0002162) and Soil total exchangeable bases
(BERVO:0002163). Soil clay fraction cation exchange capacity (BERVO:0002161) takes
ceq.kg-1{clay}.
These keep their units:
Cation exchange capacity of soil organic carbon(BERVO:0000141) was already in charge,eq.g-1{C}.- The alkalinity and acidity rows of water (
BERVO:0002057toBERVO:0002066) were already in charge,meq.L-1. Exchangeable tracers(BERVO:0001701) staysmol/{grid}. EcoSIM holds each exchangeable ion as an amount of the ion, dividing a divalent cation's share of the exchange capacity by 2 and a trivalent one's by 3. Only the array's two capacity entries are in charge, as the row's Comment says.
EcoSIM declares CEC_vr and AEC_vr as cmol kg-1, but reads them in meq/100 g and
multiplies by 10, so it holds mmol of charge per kg. The generic terms take the
conventional scale. The rows' Comments record the difference.
What the validator checks
- Every value is valid UCUM, when
ucumvertis installed. CI installs it fromsrc/scripts/requirements.txt. Without it, the validator says so in a warning. NONEis an error; the value is1.- A space is an error; UCUM joins units with
.. dwith any exponent but 1 or -1 is an error, because it is almost certainly an EcoSIM grid-cell total written as UCUM days.- A
.after a/is an error, because UCUM reads left to right.
It does not check that a unit fits its quantity.