[ferret_users] how to calculate growth rate of a variable

[Yogesh Tiwari <yogesh.mpi@xxxxxxxxxxxxxx>]

Dear Ferret Users,
I have CO2 mixing ratio(ppm) time series data during the period of 1991-2000. 
I would like to calculate CO2 growth rate /ppm.a-1

Kindly can any one advise how to calculate above in ferret.
 
My data file looks like;
 
time, year, month, day, hour, min, sec, lat, long, height, CO2
1991.476722 1991 6 24 0 5 0 -38.93 145.15 4270 353.680 
1991.476741 1991 6 24 0 15 0 -39.20 145.22 4270 353.950 
1991.476747 1991 6 24 0 18 0 -39.43 145.28 4270 353.510 
-----------------------------------------------
2000.740788 2000 9 28 3 5 0 -38.00 145.00 2280 366.750 
2000.740794 2000 9 28 3 8 0 -38.00 145.00 1830 366.550 
2000.740803 2000 9 28 3 13 0 -38.00 145.00 1220 370.550 
Many great thanks, 
 
Best Regards,
Yogesh
-- 
Yogesh K. Tiwari (Dr.rer.nat), 
Scientist,
Indian Institute of Tropical Meteorology, 
Homi Bhabha Road,
Pashan,
Pune-411008
INDIA

Phone: 0091-99 2273 9513 (Cell) 
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