求助一个关于距平场的问题

764859472

下载了2012年一日4次和daily的资料，想画6月份某点的距平场的图，
'reinit'
'sdfopen d:\4.nc'
'set grid off'
'set lon 125'
'set lat 50'
'set t 1'
'have=ave(hgt,t=725,t=848,1)'
'modify have diurnal'
'set t 725 848'
'define hano=hgt-have'
'd hano'，

grads提示modify error：time not varying for this defined variable。请问问题出在哪里？另外问一下大概的gs文件应该是啥样？

river

看一下官方的例子吧
modify

modify varname type
This command defines a climatological variable, which is year-independent. varname is a defined grid. There are two options for type:

seasonal    - For creating monthly or multi-monthly climatologies
diurnal     - For creating climatologies over a time period less than a day
Usage Notes

Example

Say you have a 50-year timeseries of monthly mean sea surface temperatures (a variable named sst with 600 time steps) and you want to create a climatology and then look at the monthly anomalies. First, set the time range for 1 to 12, to span a complete year. Second, define the variable "sstclim" which will contain the January mean in the first time step, the February mean in the second time set, etc. Then use 'modify' to turn 'sstclim' into a climatological variable. This means that the calendar year associated with 'sstclim' (the first year in the original sst data set) becomes a wild card. Then you can define the anomaly by subtracting the climatology from the original time series. The commands are as follows:

'set t 1 12'
'define sstclim = ave(sst, t+0, t=600, 12)'
'modify sstclim seasonal'
'set t 1 last'
'define anom = sst - sstclim'

lysx

学习了！！！

764859472

river 发表于 2014-9-7 07:30
看一下官方的例子吧
modify

我的资料是逐日资料，不是逐月资料。请问该怎么改？

river

764859472 发表于 2014-9-7 08:48
我的资料是逐日资料，不是逐月资料。请问该怎么改？

其实我也不知道怎么改，你说你的资料是逐日资料，那是有多少年的，还是只有很多年六月份的？你说求六月份的距平，是求多年平均后的6月份平均？问题描述不清，没有人能帮你的

lqouc

764859472 发表于 2014-9-7 08:48
我的资料是逐日资料，不是逐月资料。请问该怎么改？

1 have那一句少了个define吧
2 如果是想画距平的时间序列，根本不用modify，去掉那一句就好了

764859472

river 发表于 2014-9-7 10:58
其实我也不知道怎么改，你说你的资料是逐日资料，那是有多少年的，还是只有很多年六月份的？你说求六月份 ...

是2012年一整年逐日的资料。

river

764859472 发表于 2014-9-7 11:09
是2012年一整年逐日的资料。

就是你想求六月份每个时次的距平？那就按6楼的改