[arts-users] Problem about caculating the impact of winds
Hi Everyone, I had a question about caculating the impact of winds by using lookup table in ARTS. I use the larger frequency grid when generate the table, such as 3 GHz band, 0.5 MHz setp. However, when I caculate the y using the frequency grid with 1 GHz band and 1 MHz step, error messages occur as follow (But it is OK when I set the frequency step to 2 MHz): Runtime-error in source calculation at index 0: Run-time error in agenda: propmat_clearsky_agenda Run-time error in method: propmat_clearskyAddFromLookup Problem with gas absorption lookup table. At least one frequency is outside the range covered by the lookup table. The version of ARTS is 2.4.0. Regards, Wang___ arts_users.mi mailing list arts_users.mi@lists.uni-hamburg.de https://mailman.rrz.uni-hamburg.de/mailman/listinfo/arts_users.mi
Re: [arts-users] Calculated brightness temperature bias causes.
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 > Date: 4/20/21 6:11 AM (GMT-06:00) > To: "Thomas,Renish" > 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&data=04%7C01%7CRenish.Thomas%40colostate.edu%7C8bb1cd94b52a4724954408d903ed19cb%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C637545139171957024%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=7Qr43Du%2B54FAx%2FWFOIMnjdaHFegsWnBRslp2jGQYxb8%3D&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
Re: [arts-users] Calculated brightness temperature bias causes.
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 Date: 4/20/21 6:11 AM (GMT-06:00) To: "Thomas,Renish" Cc: "arts_users.mi@lists.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&data=04%7C01%7CRenish.Thomas%40colostate.edu%7C8bb1cd94b52a4724954408d903ed19cb%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C637545139171957024%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=7Qr43Du%2B54FAx%2FWFOIMnjdaHFegsWnBRslp2jGQYxb8%3D&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
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://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
[arts-users] Calculated brightness temperature bias causes.
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://mailman.rrz.uni-hamburg.de/mailman/listinfo/arts_users.mi
