How does the model calculate the time?

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Moderator: Katrijn

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Sou
Posts: 51
Joined: Wed Sep 03, 2014 7:46 pm
Full name: Soudeh Afsharian

How does the model calculate the time?

Post by Sou »

Hi,
I'm wondering whether the model consider 0-12 hours as the night and 12-24 as day!I tried to list the solar radiation value for 2 days and noticed that for the first 12 hours this quantity is 0 and from 12-24 it has values. Is that right? If so, it's not realistic!

1 / 1: 0.0
2 / 2: 0.0
3 / 3: 0.0
4 / 4: 0.0
5 / 5: 0.0
6 / 6: 0.0
7 / 7: 0.0
8 / 8: 0.0
9 / 9: 0.0
10 / 10: 0.0
11 / 11: 0.0
12 / 12: 0.0
13 / 13: 56.1
14 / 14: 148.1
15 / 15: 239.8
16 / 16: 317.4
17 / 17: 372.8
18 / 18: 401.3
19 / 19: 400.9
20 / 20: 371.6
21 / 21: 315.5
22 / 22: 237.4
23 / 23: 145.5
24 / 24: 53.7
25 / 25: 0.0
26 / 26: 0.0
27 / 27: 0.0
28 / 28: 0.0
29 / 29: 0.0
30 / 30: 0.0
31 / 31: 0.0
32 / 32: 0.0
33 / 33: 0.0
34 / 34: 0.0
35 / 35: 0.0
36 / 36: 0.0
37 / 37: 56.1
38 / 38: 148.1
39 / 39: 239.8
40 / 40: 317.4
41 / 41: 372.8
42 / 42: 401.3
43 / 43: 400.9
44 / 44: 371.6
45 / 45: 315.5
46 / 46: 237.4
47 / 47: 145.5
48 / 48: 53.7


thank you,
Sou
ropponen
Posts: 7
Joined: Thu Dec 04, 2014 11:45 am
Full name: Janne Ropponen

Re: How does the model calculate the time?

Post by ropponen »

Hi Sou!

Have you checked that the time_zone model parameter is set correctly? From the manual:
time_zone: Time zone, i.e. the difference of the local time with respect to GMT [hours]. Difference is positive (negative) eastwards (westwards) from Greenwich (0).

The parameter time_zone is of type REAL and must be between -12.0 and 12.0 and is used to reset the start and end dates to GMT where necessary. A time zone must be given for the calculation of solar radiance and the astronomical Greenwich argument at the local time when the start and end dates are not expressed in GMT.
Sou
Posts: 51
Joined: Wed Sep 03, 2014 7:46 pm
Full name: Soudeh Afsharian

Re: How does the model calculate the time?

Post by Sou »

ropponen wrote:Hi Sou!

Have you checked that the time_zone model parameter is set correctly? From the manual:
time_zone: Time zone, i.e. the difference of the local time with respect to GMT [hours]. Difference is positive (negative) eastwards (westwards) from Greenwich (0).

The parameter time_zone is of type REAL and must be between -12.0 and 12.0 and is used to reset the start and end dates to GMT where necessary. A time zone must be given for the calculation of solar radiance and the astronomical Greenwich argument at the local time when the start and end dates are not expressed in GMT.
Hi,
Yes I included (-5) for my time zone. So I assume the outputs are on standard time bases not local time, right? If so, then I can say that 12-5= 7, so the first 12 zeroes are form 7pm to 7am. If that's a case, then my problem is solved! do you agree with me?
thank you:)
Sou
Katrijn
Posts: 87
Joined: Fri Nov 29, 2013 3:04 pm
Full name: Katrijn Baetens

Re: How does the model calculate the time?

Post by Katrijn »

Hi Sou,

changing the time zone does not change the output times and values (you can double check by changing the time zone in the cones test case if you want). I don't know if you use amplitudes and phases at the boundaries? if so, pay attention to the fact that the phase is dependent on the time reference. that is probably what's causing the unwanted time shift in your results.
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