The PMIP Variables


Note: the PMIP variables were originally defined in Newsletter 6. Make sure you read this newsletters to understand all the technical details!

 

 

 

Group 1 variables

The following variables are functions of longitude, latitude, time (in the case of seasonal and monthly data), and for zg, ta, u, v, hus, hur, stfuv, and potuv they are also a function of pressure level (as indicated in the NOTES column).

     
NameUnitsTitleNotes
orogmSurface Elevation   
sftland%Percentage Land % of grid cell that is land1
seaice%Percentage of Area Covered by Sea Ice % of area of grid cell that is sea-ice covered; i.e., 100 times the product of (fraction of time sea ice is present in cell) and (fraction of cell covered) 2
snow%Percentage of Area Covered by Snow % of area of grid cell that is snow covered; i.e., 100 times the product of (fraction of time snow is present in cell) and (fraction of cell covered)2
simkg/(m²)Sea Ice Mass per Unit Area   
rsdtW/(m²)TOA Incident Shortwave Radiation insolation (+ down) 
rsutW/(m²)TOA Reflected Shortwave Radiation + up 
rltW/(m²)TOA Outgoing Longwave Radiation + up 
rsdsW/(m²)Surface Incident Shortwave Radiation + down 
rsusW/(m²)Surface Reflected Shortwave Radiation + up 
rlsW/(m²)Surface Net Longwave Radiation + down 
hfssW/(m²)Surface Sensible Heat Flux + down 
hflsW/(m²)Surface Latent Heat Flux + down 
mrsokg/(m²)Soil Moisture AMIP units were cm 
snmkg/(m²)Snow Mass per Unit Area mass of snow on ground per unit area 
mrromm/dayRunoff   
prmm/dayTotal Precipitation include liquid & solid phase, convective & large scale precip 
prcmm/dayConvective Precipitation if available; (include both liquid & solid phase precip.) 
prsnwemm/daySnowfall (Liquid Water Equivalent) include both convective & large scale 
evsmm/daySurface Evaporation include both evaporation & sublimation  
prwkg/(m²)Total Precipitable Water AMIP units were mm 
tasCSurface Air Temperature 2-meter screen temp 
tgCGround Temperature skin temperature 
pmslhPaMean Sea Level Pressure   
usfcm/sEastward Surface Wind Speed at 10 m 
vsfcm/sNorthward Surface Wind Speed at 10 m 
tauuN/(m²)Eastward Surface Wind Stress at surface 
tauvN/(m²)Northward Surface Wind Stress at surface 
hursfc%Surface Relative Humidity at 2 m 
clt%Total Cloudiness % of atmospheric column covered by clouds 
clwg/(m²)Cloud Water Content if available 
rltcsW/(m²)TOA Outgoing Longwave Clear Sky Radiation Method II; + up3
rstcsW/(m²)TOA Net Shortwave Clear Sky Radiation (net=incident-reflected) + down3
rlscsW/(m²)Surface Net Longwave Clear Sky Radiation Method II; + down3
rsdscsW/(m²)Surface Incident Shortwave Clear Sky Radiation Method II; + down3
rsuscsW/(m²)Surface Reflected Shortwave Clear Sky Radiation Method II; + up3

1 In calculating the "Percentage Land" for a grid cell, include sea ice as "ocean" and glacial ice as "land". For models with non-fractional coverage of land or ocean within a grid cell, the "Percentage Land" should either be 0.0 or 100.0.

2 In calculating "Percentage Sea Ice" for a grid cell, compute
(100/n) * [sum-over-n f-sub-n]
where n is the time-index and f-sub-n is the fraction of sea ice in the grid cell at time n. For models that allow a grid cell to be partially ocean and partially land, the fraction of sea-ice in the grid cell should be calculated relative to the total area of the cell, not just the ocean area.

3 Method II for calculating clear-sky fluxes is the normal procedure used in model-model intercomparisons (see, for example, Cess, R.D. and G.L. Potter, 1987: Exploratory studies of cloud radiative forcing with a general circulation model. Tellus, 39A, 460-473) The clear-sky fluxes are computed during each sampling interval and then time-averaged (without weighting by cloud fraction).

 

Group 2 variables

The following variables are functions of longitude, latitude, pressure level (as indicated in the NOTES column), and time (in the case of seasonal and monthly data).

NameUnitsTitleNotes
zgmGeopotential Height at 200, 500 and 850 hpa
taCTemperature at 200 and 850 hpa
um/sEastward Wind Speed at 200 and 850 hpa
vm/sNorthward Wind Speed at 200 and 850 hpa
husg/kgSpecific Humidity at 200 and 850 hpa
hur%Relative Humidity at 200 and 850 hpa
stfuvm²/sHorizontal Wind Velocity Stream Function at 200 and 850 hpa
potuvm²/sHorizontal Wind Velocity Potential at 200 and 850 hpa
 

Group 3 variables

The following variables are functions of latitude, pressure level and time (in the case of seasonal and monthly data). The pressure levels od the cross sections are : 10, 20, 30, 50, 70, 100, 150, 200, 250, 300, 400, 500, 700, 850, 1000 hPa.

NameUnitsTitleNotes
um/sEastward Wind Speed  
vm/sNorthward Wind Speed  
taCTemperature  
husg/kgSpecific Humidity  
hur%Relative Humidity  
clt%Percent Clouds % of layer occupied by clouds
stfmmm²/sMean Meridional Stream Function  

Home Top Last updated 2001/10/09 16:35:54