For many transformations, particularly when automated, please use the udunits2 software where possible. For example, in R, you can use
library(udunits2)
## transform meters to mm
ud.convert(10, "m", "mm")
## equivalently, via the udunits synonym database
ud.convert(10, "meters", "millimeters")
## it can also handle more complex units
ud.convert(10, "m/s", "mm/d")
NB: Many of these conversions have been automated within PEcAn{target="_blank"}.
Table: Useful conversions for entering site, management, yield, and trait data [To-Do: Fix these!]
| From ((X)) | to ((Y)) | Conversion | Notes |
|---|---|---|---|
| (X_2=) root production | (X_1=) root biomass & root turnover rate | (Y = X_2/X_1) | Gill (2000) |
| DD(^{\circ}) MM' SS'' | XX.ZZZZ | (\textrm{XX.ZZZZ} = \textrm{DD} + \textrm{MM}/60+\textrm{SS}/3600) | to convert latitude or longitude from degrees, minutes, seconds to decimal degrees |
| lb | kg | (Y=X\times 2.2) | |
| mm/s | (\mu) mol CO(_2) m(^{2}) s(^{-1}) | (Y=X\times 0.04) | |
| m(^2) | ha | (Y = X/10^4) | |
| g/m(^2) | kg/ha | (Y=X\times 10) | |
| US ton/acre | Mg/ha | (Y = X\times 2.24) | |
| m(^3)/ha | cm | (Y=X/100) | units used for irrigation and rainfall |
| % roots | root:shoot (q) | (Y=\frac{X}{1-X}) | (% \text{roots} = \frac{\text{root biomass}}{\text{total biomass}}) |
| (\mu) mol cm(^{-2}) s(^{-1}) | mmol m(^{-2}) s(^{-1}) | (Y = X/10) | |
| mol m(^{-2}) s(^{-1}) | mmol m(^{-2}) s(^{-1}) | (Y = X/10^6) | |
| mol m(^{-2}) s(^{-1}) | (\mu) mol cm(^{-2}) s(^{-1}) | (Y = X/ 10^5) | |
| mm s(^{-2}) | mmol m(^{-3}) s(^{-1}) | (Y=X/41) | Korner et al. [1988] |
| mg CO(_2) g(^{-1}) h(^{-1}) | (\mu) mol kg(^{-1}) s(^{-1}) | (Y = X\times 6.31) | used for root_respiration_rate |
| (\mu) mol | mol | (Y= X\times 10^6) | |
| julian day (1--365) | date | see https://www-air.larc.nasa.gov/tools/jday.htm{target="_blank"} (NASA Julian Calendar) | |
| spacing (m) | density (plants m(^{2})) | (Y=\frac{1}{\textrm{row spacing}\times\textrm{plant spacing}}) | |
| kg ha(^{-1}) y(^{-1}) | Mg ha(^{-1}) y(^{-1}) | (Y= X/1000) | |
| g m(^{-2}) y(^{-1}) | Mg ha(^{-1}) y(^{-1}) | (Y= X/100) | |
| kg | mg | (Y=X\times 10^6) | |
| cm(^2) | m(^2) | (Y=X\times 10^4) |