Hi,

Just by numbers:

RJBT at 300 K 183 GHz is 3.086705214957283e-15

Planck at 300 K 183 GHz is 3.0417434132511342e-15

This means you expect a 1.5 % difference, or about 4.5 K between them.

With hope,
//Richard

Den tis 20 apr. 2021 kl 13:22 skrev Thomas,Renish <
renish.tho...@colostate.edu>:

> Hi Stephan,
>
> I am using Rayleigh jeans. As I need to activate cloud box in some
> instances.
>
> I understand that RJBT instead of Planck can cause a dip in the brightness
> temperatures. Is this the only factor that can cause a bias, or does
> pressure levels, lat/lon grid resolution also cause a bias?
>
> Thanks,
> Renish
>
>
> -------- Original message --------
> From: Stefan Buehler <stefan.bueh...@uni-hamburg.de>
> Date: 4/20/21 6:11 AM (GMT-06:00)
> To: "Thomas,Renish" <renish.tho...@colostate.edu>
> Cc: "arts_users.mi@lists.uni-hamburg.de" <
> arts_users...@mailman.rrz.uni-hamburg.de>
> Subject: Re: [arts-users] Calculated brightness temperature bias causes.
>
> Dear Renish,
>
> do you use Planck or Rayleigh-Jeans brightness temperature? For Planck,
> you should indeed approach the ambient temperature if you go low enough.
>
> Cheers
>
> Stefan
>
> On 20 Apr 2021, at 12:46, Thomas,Renish wrote:
>
> > Hi Everyone,
> >
> > I had some questions about the calculated brightness temperature in
> > ARTS.
> >
> > When I calculate the brightness temperature for an atmospheric
> > scenario in "horizon looking mode" and in clearsky. I get a brightness
> > temperature at 183.31 GHz (Water vapor absorption line), which is
> > about 3 to 6 degrees lower than the ambient temperature.
> >
> > I would assume that at the water vapor absorption line and at low
> > altitudes (~2 km above sea level), I should measure very close to the
> > ambient temperature (Due to high absorption).
> >
> > So, my questions are:
> >
> > 1.)  Is this brightness temperature bias expected?, or can something
> > else cause this?
> >
> > Thanks,
> > Renish
> > _______________________________________________
> > arts_users.mi mailing list
> > arts_users.mi@lists.uni-hamburg.de
> >
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmailman.rrz.uni-hamburg.de%2Fmailman%2Flistinfo%2Farts_users.mi&amp;data=04%7C01%7CRenish.Thomas%40colostate.edu%7C8bb1cd94b52a4724954408d903ed19cb%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C637545139171957024%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=7Qr43Du%2B54FAx%2FWFOIMnjdaHFegsWnBRslp2jGQYxb8%3D&amp;reserved=0
> _______________________________________________
> arts_users.mi mailing list
> arts_users.mi@lists.uni-hamburg.de
> https://mailman.rrz.uni-hamburg.de/mailman/listinfo/arts_users.mi
>
_______________________________________________
arts_users.mi mailing list
arts_users.mi@lists.uni-hamburg.de
https://mailman.rrz.uni-hamburg.de/mailman/listinfo/arts_users.mi

Reply via email to