Dynamic and Buoyancy Pressure

1
Dynamic and Buoyancy Pressure

• A rising thermal
• plus
• Unix basics

2
Some Unix basics(basis of Linux and Mac OS X)

• The command prompt is (do not type it)
• Unix commands presented in Courier font
• ls
• lists your visible files
• ls -a
• lists all files, including invisible
• ls -al
• lists all files, includes size other info
• pwd
• print working directory - shows your location

3
Some Unix basics(continued)

• mkdir TEST
• makes a directory called TEST
• cd TEST
• changes directory to TEST
• cd ..
• moves UP in directory hierarchy
• cd TeST
• command should FAIL Unix is CASE SENSITIVE

4
Some Unix basics(continued)

• touch crap.txt
• makes an empty file
• nedit crap.txt
• invoked Notepad-like text editor
• add some text, save file and exit
• ls -al crap.txt
• see its there
• cp crap.txt crap.txt.backup
• make a copy with cp
• rm crap.txt
• the remove command
• if it removes file without prompting, we need
  to fix that!

5
Some Unix basics(continued)

• mkdir BACKUP
• makes a new directory
• cp crap.txt.backup BACKUP/.
• type exactly as written - there is a space
  before the period
• the period means keep the same name
• ls -al BACKUP/
• see a copy is in the new location
• mkdir BACKUP/more_backup
• a new subdirectory in a directory
• cd BACKUP/more_backup
• move to new subdirectory
• cd
• pwd
• cd by itself always takes you to your home
  directory

6
Some Unix basics(continued)

• cp /home/fovell/part .
• asterisk is wild card character
• copies all files matching text pattern to your
  directory
• ls part
• lists files matching pattern
• cat part1 part2 gt both_parts
• concatenates files
• greater-than sign is output redirect
• more both_parts
• more lists contents, one screen at a time
• hit space bar for next screenfull, type q to
  quit

7
Your Unix PATH

• cp /home/fovell/execute_me .
• execute_me
• - if you receive execute_me command not found
  your PATH needs changing
• - The PATH is an environment variable that tells
  Unix where to find stuff, and the order in which
  to look
• ./execute_me
• - this forces Unix to look in the current
  directory for the program to run

8
Preparation for new usersold users may have a
.cshrc file instead

• cd
• mv .tcshrc .tcshrc_backup
• mv is move command
• .tcshrc or .cshrc is a script file of commands,
  paths, etc., executed for every new terminal
  window
• cat .tcshrc_backup /home/fovell/cshrc_additions_
  fovell gt .tcshrc
• type exactly as shown
• source .tcshrc
• changes to script file in present window do not
  take effect until sourced
• greater-than sign is output redirect
• rm both_parts
• now you should be prompted to confirm file
  removal!
• \rm both_parts
• how to override prompt

9
DTDM on our Synoptic Lab Linux computers
Synoptic Lab computers open during business
hours ONLY and printing is very difficult cp
/home/fovell/DTDM_package_linux.tar . note
space and period! tar xvf DTM_package_linux.t
ar cd DTDM make makes the dtdm executable
file
10
Using DTDM - 2
dtdm lt input_thermal.txt runs model, makes
output less-than sign provides contents of
txt file to the dtdm executable gradsnc
-l starts up GrADS ga-gt is GrADS
prompt ga-gt open thermal.anelastic ga-gt query
file
11
Using DTDM - 3
File 1 DTDM demo simulation Descriptor
thermal.anelastic.ctl Binary
thermal.anelastic.dat Type Gridded Xsize
99 Ysize 1 Zsize 82 Tsize 11 Number of
Variables 17 u 82 0 horizontal velocity
up 82 0 pert horizontal velocity w 82 0
vertical velocity th 82 0 potential
temperature thp 82 0 pert potential
temperature pi 82 0 ndim pressure pip 82
0 pert ndim pressure ppmb 82 0 pert pressure
in millibars pbyc 82 0 buoyancy pressure in
millibars pdyn 82 0 dynamic pressure in
millibars ptot 82 0 total pressure in
millibars dudtd 82 0 U acceleration -
dynamic dudtb 82 0 U acceleration - buoyancy
dudtt 82 0 U acceleration - total dwdtd 82
0 W acceleration - dynamic dwdtb 82 0 W
acceleration - buoyancy dwdtt 82 0 W
acceleration - total
running dtdm model created two new GrADS
files thermal.anelastic.ctl thermal.anelastic.dat
contents of thermal.anelastic.ctl shown at
left
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ga-gt set t 6ga-gt start.gsga-gt d thp
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ga-gt d ppmb
14
ga-gt cga-gt set ccolor 1ga-gt d pbyc
15
ga-gt cga-gt set ccolor 1ga-gt d pdyn
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ga-gt cga-gt set ccolor 1ga-gt d w
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ga-gt cga-gt set gxout shadedga-gt d wga-gt set
gxout contourga-gt set ccolor 1ga-gt d dwdttga-gt
scripts/cbarn.gs
dwdtt is Lagrangian dw/dt, not Eulerian
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ga-gt cga-gt set t 9ga-gt set ccolor 1ga-gt set
cint 2ga-gt d w
19
scripts/thermal.gs
'set mproj off' 'set display color
white' 'clear' 'set grads off' 'scripts/rgbset.gs'
plot w 'set x 30 70' 'set gxout shaded' 'set
clevs -12.5 -10 -7.5 -5 -2.5 0 2.5 5 7.5 10
12.5' 'set ccols 49 47 45 43 41 0 61 62 63
65 67 69' 'd w' 'scripts/cbarn.gs' 'set gxout
contour'
20
Final cautions

• Make backups
• This command runs the model
• dtdm lt input_thermal.txt
• This command destroys the input file!
• dtdm gt input_thermal.txt

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ga-gt set t 6ga-gt scripts/thermal.gs