* This script computes the average over end of cent. dry regional avg (a regioanl projection)
* A way to test the persistency of prec patterns or trends in prec anomalies.
* of prec patterns or trends in prec anomalies. 
* data are saved from prec_write.gs for sesonal averages.  
* anomalies relative to base period 1901-1960.

 'reinit'
 'open pra_jja_1850-2100_0160.ctl'

* define eoc centered on 2085 30yr avg and 30yr running mean
 'set t 15 236'
 'define pa2085m=ave(pra,t=221,t=250)'
 'define pa30m=ave(pra,t-14,t+15)' 

 'set lon 0 360'
 'set lat -90 90'
* 'set t 15 236'
* define prec anom greater and less than 0 (areas < 0 set to undefined)
 'define pa2085mdry1=maskout(pa2085m,-pa2085m)'
 'define pa2085mwet1=maskout(pa2085m,pa2085m)'

* define wet & dry regions of 30yr rm anoms that are > or < 0 of 30yr eoc avg 
 'define pa30mdry1=maskout(pa30m,-pa2085m)'
 'define pa30mwet1=maskout(pa30m,pa2085m)'

 'set x 1'
 'set y 1'
 
* aave does not include undefined values in its averaging
 'define pdryproj1=aave(pa30mdry1,lon=0,lon=360,lat=-23,lat=23)'
 'define pwetproj1=aave(pa30mwet1,lon=0,lon=360,lat=-23,lat=23)'

 'set vpage 0 8.5 5.5 11'
 'set grads off'
 'set grid off'

 'set cmark 0'
 'set ccolor 3'
 'd pwetproj1'
 'draw title \\cnrm JJA 23S-23N avg over eoc WET region avg \\Relative to 1901-1960'
 'draw string 2.25 4.5 Wet: aave 30yr runmean > 0 for eoc 30yr avg'

 'set vpage 0 8.5 0 5.5'
 'set grads off'
 'set grid off'

 'set cmark 0'
 'set ccolor 8'
 'd pdryproj1'

'draw title \\cnrm JJA 23S-23N avg over eoc DRY region avg'
 'draw string 2.25 4.5 Dry: aave 30yr runmean < 0 for eoc 30yr avg'

 'print'
 '!mv grads.eps cnrm_wetdry_jja_regional_ave_23S-23N_0160.eps'


* define clim, anom.
function ca(var,t1,t2)
 'set time 't1' 't2
* climatology
 'define 'var'c=ave('var',t+0,time='t2',1yr)'
 'modify 'var'c seasonal'
*anom
 'define 'var'a='var'-'var'c'

 say 'mean, anom, are defined for  ' var

return
**********