pressure coordinates

[w_xuej@163_com]

I know  interpolating CESM hybrid coordinates to pressure coordinates by using "vinth2p".There are 26 pressure layers, how much is each layer? Besides,is there any tools to interpolate pressure coordinates to hybrid coordinates? Thank you!

 

[hannay]

As you have 26 levels, I assume you are talking about CCSM4 and CESM.

I am not sure I understand your question: "There are 26 pressure layers, how much is each layer?"
Do you mean what are the values for hybrid levels in ccsm4 ?  
You can look at the variable lev in the outfile files:  lev = 3.54463800000001, 7.38881350000001, 13.967214, 23.944625,     37.2302900000001, 53.1146050000002, 70.0591500000003, 85.4391150000003,     100.514695, 118.250335, 139.115395, 163.66207, 192.539935, 226.513265,     266.481155, 313.501265000001, 368.817980000002, 433.895225000001,     510.455255000002, 600.524200000003, 696.796290000003, 787.702060000003,      867.160760000001, 929.648875000002, 970.554830000001, 992.5561 ; 

  

 

[w_xuej@163_com]

Thank you for your reply.I mean that values for pressure levels in CESM corresponding to each hybrid layer.Besides,is there any tools to interpolate pressure coordinates to hybrid coordinates?

 

[hannay]

You can compute pressure from hyam and hybm. At each latitude, longitude and level (lev[k]) pressures are computed using: p(k) = hyam(k)*PO + hybm(k)*PS

 

[w_xuej@163_com]

Thank for your reply.Is there a *.F90  to interpolate pressure coordinates to hybrid coordinates in CESM? or I need to write a procedure by myself?Thank you !

 

[hannay]

I am not aware of any fortran program that does this. 

 

[Yuan Wang]

Hi Hannay, Can I ask how the one-dimensional "lev" is calculated in the model output? I assume each grid point should have different pressure levels based on the hybrid pressure-sigma coordinate system. Thanks in advance,Yuan

 

[eaton]

lev is 1000.*(hyam + hybm) where hyam and hybm are the hybrid coordinate A and B values at the layer midpoints.