Scheduled Downtime
On Tuesday 24 October 2023 @ 5pm MT the forums will be in read only mode in preparation for the downtime. On Wednesday 25 October 2023 @ 5am MT, this website will be down for maintenance and expected to return online later in the morning.
Normal Operations
The forums are back online with normal operations. If you notice any issues or errors related to the forums, please reach out to help@ucar.edu

Accessing Surface Pressure within CAM Module

Hi,I am looking to access the value of the surface pressure at a gridbox for use in a parameterization I am trying to implement within the mo_lightning.F90 module in CAM5. In looking at other examples in the code I came across the reference "state(c)%ps(i)" which I assume gives the surface pressure at a chunk "c" and column "i." When I print out the value of this to a log file however I am getting values between 600 and 700 hPa, which are too low to be surface pressures. I'm wondering if anyone has encountered this issue before or has suggestions for the best way to go about accessing the surface pressure within CAM5.Thank you for your help,Spencer
 

eaton

CSEG and Liaisons
The surface pressure is in the state object, state%ps as you've seen.  Pressures between 600 and 700 hPa are certainly reasonable at certain spots on the globe. 
 

santos

Member
I don't know how many of those values you are getting, but 700 hPa is completely reasonable for columns located over tall mountain ranges. Some columns may have an average surface height that's several kilometers above sea level, so ps is much lower than 1000 hPa at those columns.
 
Yes, I understand that in some locations these pressures might be reasonable, but the issue is that I'm seeing these values at all columns (and gridboxes). I see no columns where the surface pressure is near 1000 hPa, which makes me wonder whether I am doing things correctly. Spencer
 
Top