关于时次的设定的疑问，求大师帮忙

lt9171

'reinit'
'open e:/grads/h/h500.ctl'
'set parea 1 10 1 8'
'set grads off'
'set grid off'
'set xlopts 1 5 0.16'
'set ylopts 1 5 0.16'
'set map 1 1 10'
'set t 1 12'
'have=ave(h,t+0,t=48,12)'
'modify have seasonal'
'set t 1 48'
'hano=h-have'
'set time dec1982'
'set gxout shaded'
'set cmax 0';'d hano'
'set gxout contour';'d hano'
'draw title 500hPa anomalous height fields for Dec1982'
'draw xlab LON';'draw ylab LAT'
'print'
pull dumy
想问下这两个t都代表什么意思呢？希望看到的人帮个忙啊，谢谢了

river

去看 传说中的谁 分享一个经验贴吧