How is a hourly averaged parameter computed?

[jahirbgoode]

Hello.

I'm modelling heat transfer in a domain that's being heated by many sources, one of them being solar radiation. I did the computations on many solar geometry angles every 10 minutes and got to the point where the measured daily insolation (provided by POWER) is nearly equal to the one I get from the mathematical model. This is, mostly, because I'm using the All Sky Insolation Clearness Index (ALLSKY_KT) alongsinde the solar angles and the solar constant acoording to the time and place I'm studying.

The problem arises when I try to compute the energy received at near 90°zenith angle (sunrise and sunset) becuase KT is given on a hourly basis and the values around these times should be smaller than the neighbouring hourly average. I used some correlations in order to compute the air mass and then KT but the values (at least for the sunrise) seem to be way smaller and I get an abrupt change between the computed values and the ones I got from POWER.

So my question is, how the hourly average is computed? Is the value of HR = 6 the average between 6 AM and 7 AM? This is a very simple question but I'd prefer to be certain about the numbers I'm using.

Thanks!

EDIT: I'm evaluating solar irradiance at 29.03° North for September 24th up until the 26th.

[ASDC - David W.]

Hi jahirbgoode,

A subject matter expert has been contacted relating to your question on how the hourly averaged parameter is computed.

Thank you,

David W.
NASA Langley ASDC DAAC Lifecycle

[ASDC - pstackhouse]

Dear Jahirbgoode,

To get started to answer this question, it would help you could specify the latitude and time period of the data that you are evaluating? This will impact the final answer.

Thanks.

Paul Stackhouse

[jahirbgoode]

Hello, Paul.

Right now, I'm evaluating solar irradiance at 29.03° North for September 24th up until the 26th.

Thanks.

[jahirbgoode]

Hi, Whitney.

I specified it in my last comment. I edited the original post too and just in case it's for 29.03° North for September the 24th to 26th.