Dear friend
one question of mine is about cycle_length.
What cycle_length do in climatology file? Does it mean that climatology fields will repeat for latter years with 360 or 365.25 days as a cycle? or clomatology data are just for first year?
Also i can not completely find that what different between choosing 360 or 365.25 as a cycle_length is. When 360 is correct and when 365.25? i think it is not related to leap year because it just add 1 day to year's day.
Thanks for any note
cheers
jafar
lenght_cycle
Re: lenght_cycle
cycle_length means that that field will repeat after a certain number of days. If you pick a cycle_length of 360, then apply a wind forcing with 365/366 days per year, your climatology seasons will become shifted after a few years. If you only run for one or two years, it doesn't matter that much. For an idealized problem, months of 30 days is a nice clean way to go, so a cycle_length of 360 is perfect for that. What exactly are you planning to do? Run for decades of an idealized problem? Run for one year only? Run with three-hourly realistic winds with a real calendar?
Re: lenght_cycle
at first thanks for your reply
All forces of mine are for 365/366 days per year, and i want to run model for 5 years. So if cycle_length be 360, climatology's fields will shift about five days per year and after 5 years, climatology season will shift to Early days of previous month . Therefore it seems that lcycle_length of 356.25 it better
. Is not it?
If climatology fields are as a auxiliary field to reach to approximately good results, it will be helpful just for first year results. because if exactly same climatology 's fields repeat for latter years, it will be effect on results which obtained by solving State and Navier Stoke equations in latter years, too. Therefor climatology's filed will play a role as a external force to restrict resulted fields in latter years
.
especially when climatology's fields were far rome Reality, will have negative effect on model results
I become appreciate to receive you idea about it
all the best
jafar
All forces of mine are for 365/366 days per year, and i want to run model for 5 years. So if cycle_length be 360, climatology's fields will shift about five days per year and after 5 years, climatology season will shift to Early days of previous month . Therefore it seems that lcycle_length of 356.25 it better
. Is not it?If climatology fields are as a auxiliary field to reach to approximately good results, it will be helpful just for first year results. because if exactly same climatology 's fields repeat for latter years, it will be effect on results which obtained by solving State and Navier Stoke equations in latter years, too. Therefor climatology's filed will play a role as a external force to restrict resulted fields in latter years
.especially when climatology's fields were far rome Reality, will have negative effect on model results
I become appreciate to receive you idea about it
all the best
jafar
Re: lenght_cycle
It sounds like you want a cycle_length of 365.25 days.
As for climatology nudging, it is one tool, but a rather blunt tool. Ideally, you won't need it at all and can get a reasonable result without it. I would try that first. Then, if you evaluate your results and find that things are drifting you can either figure out why and fix it or use climatology nudging as a bandaid. We have one domain where the boundary conditions were building up oddities and a band of climatology nudging just at the edge helped control that, but usually we try to avoid climatology nudging.
As for climatology nudging, it is one tool, but a rather blunt tool. Ideally, you won't need it at all and can get a reasonable result without it. I would try that first. Then, if you evaluate your results and find that things are drifting you can either figure out why and fix it or use climatology nudging as a bandaid. We have one domain where the boundary conditions were building up oddities and a band of climatology nudging just at the edge helped control that, but usually we try to avoid climatology nudging.