What is meant by the inputs to the NRLMSISE-00 Atmosphere Model?

In the documentation for the NRLMSISE-00 Atmosphere Model, there are four inputs that I find confusing.

https://se.mathworks.com/help/aeroblks/nrlmsise00atmospheremodel.html

Port 2 - N years, specified as an array.

Port 3 - N days of a year (1 to 365 (or 366)), specified as an array.

Port 4 - N seconds in a day, specified as an array, in universal time (UT).

Port 5 - N local apparent solar timed, specified as an array, in hours.

What is meant and why an array for each of them?

Answer 1

[Jinal]

Hi Maria,

As per my understanding, you wish to know about certain input ports of the NRLMSISE-00 Atmosphere Model block. Please find below a brief explanation of the same.

Port_2 – Years : Year Port_3 – Days : day of the year Port_4 – Seconds : Time of the day in universal time Port_5 – Local solar time : local apparent solar time, which refers to the time based on the current position of the sun. By default, these inputs are supposed to be specified as an array.

An input parameter called ‘Input local apparent solar time’ is also available for the block. You need to select this check box to input the local apparent solar time. By default it is set to ‘off’. You can refer this link for more information.

Hope this helps.

[Maria]

Thanks for your answer. It makes it a bit more clear, but I am still confused why there should be an array. For example, why should the year be an array? What is varying along the array?

[Jinal]

I believe array is just the structure used for storing the input values. The year array would only contain one element. Similarly the days, seconds and local solar time arrays would also be of size one.

[Smit]

Hi,

I am still confused about the N seconds in a day in UT. Is there a way to determine this parameter? Is it always going to be a constant number such as 86400?

Let me know.

Thanks!