----- Original Message -----
Sent: Wednesday, December 12, 2001 10:26
AM
Subject: Re: anomaly
Hi Shen
I have anomalies implemented on our LAS for GTSPP and WOD98
subsurface temperature data.
See the section called "Subsurface Temperature, Isotherm Depth and
Anomalies". The first two GTSPP items contain a monthly anomaly option,
and the third computes seasonal anomalies. Both of these are done with
simple custom .jnl files. See the LAS documentation on custom
initialization scripts.
Here is the part of one of my .xml files that points to a custom .jnl
file:
<!-- GTSPP Subsurface Temperature -->
<subsurf1deg_nc name="1. GTSPP Real-Time, Monthly, Aug 1996 - present"
url="file:/las/las_data/subsurf1deg.nc"
doc="doc/subsurf1deg.nc.html">
<institution name="Pacific
Fisheries Environmental Lab" url="http://www.pfeg.noaa.gov"/>
<variables>
...
...
...
<anomaly name="3. Subsurface
Temperature Anomaly">
<link
match="/lasdata/grids/subsurf1deg_nc_lon_lat_depth_time_series_grid"/>
<properties>
<ferret>
<init_script>subsurf_anom</init_script>
(add a line like this to your xml file)
<fill_levels>"(-4,4,1)(-10,-4,2)(4,10,2)"
</fill_levels>
<contour_levels>(-11000,11000,22000)
(don't want contours)
</contour_levels>
<palette>light_centered.spk
</palette>
</ferret>
</properties>
</anomaly>
The file subsurf_anom.jnl is located in
../lasxml/server/custom
and has the following in it:
set data "/las/las_data/woa98_clim.nc"
set data "$1"
define
axis/x=2.5:357.5:5/unit=degrees/modulo xaxis1
define
axis/y=-87.5:87.5:5/unit=degrees yaxis1
define grid/x=xaxis1/y=yaxis1
subsurf_grid
let
anomaly=t_mean[gxy=subsurf_grid@AVE]-temp[gxy=subsurf_grid@AVE,d=1]
set
var/title="GTSPP Temperature Anomaly (Deg C)" anomaly
The first line is the climatology file
The second line gets the name of the monthly mean file (subsurf1deg.nc
defined in xml file) from the LAS, but you could insert a file name here too
if you want.
Ignore the define axis and grid lines - I compute 5-degree averages from
the 1-degree averages in the
subsurface data files. Also ignore the gxy=...@AVE, but remember to
put include the "d=1" for the climatology dataset number.
That's all there is to it (I think - I could be forgetting something else
I had to do).
I also have an option to compute seasonal (3-month) averaged anomalies,
but that initialization script is a little more complicated. Let
me know if you have any further questions. Lynn
At 8:56 AM -1000 12/12/01, shen yingshuo wrote:
hi there, i wonder if anyone can help me
out. i want my las to show anomaly (monthly - long term
mean)...
of course las can show the difference of two
file (say the diff between jan 1979 and longterm mean of
jan). but that does not satify some researchers who want to get an
anomaly t line plot. say from jan 1950 to dec. 1999 which
means.. ( jan.1950-Ltmean jan, feb.1950-Ltmean feb, and .... dec. 1999
- Ltmean dec). i have already created all the monthly mean data
(which can be linked all together by a des file) and also i have created a
long term mean data (averaged all jan, feb, ... dec. from 1950 to 1999
respectively)..
for reference, please see http://apdrc.soest.hawaii.edu/las
check SODA data
Shen Yingshuo
IPRC-SOEST
Univ. of Hawaii
--------------------------------------------
Lynn
deWitt
ldewitt@pfeg.noaa.gov
Pacific Fisheries Environmental
Laboratories
1352 Lighthouse Avenue
Pacific Grove,
CA 93950-2097
(831)-648-9036