Dear all

I wonder if any body let me know what does mean this term in CERES-
Wheat 2.0 which Ritchie and Godwin used to photoperiod calculation
as following:

"In the model, calculated photoperiods include civil twilight".

Many thanks
Abdolali
Abdolali Ghaffari PhD student
(MCR) Wye College, University of London
Wye, Ashford
Kent TN25 5AH UK
Tel:+44-(0)1233 812401 ext. 391
Fax:+44-(0)1233 812855
E-Mail: [log in to unmask]