Tropospheric Transmission Curves for radioastronomical observatories

N. Schneidera,b, J. Urbanc, P. Barond
aIRFU/SAp CEA/DSM, Laboratoire AIM CNRS - Universite Paris Diderot, F-91191 Gif-sur-Yvette, France
bLAB/Observatoire de Bordeaux, Floirac/France
cChalmers University of Technology, Department of Radio and Space Science, 41296 Goeteborg, Sweden
dNational Institute for Communication and Information Technology, Koganei, Tokyo, Japan


For astronomical and aeronomical observations in the mm/submm/FIR range, it is of prime importance to asses the quality of the atmosphere in terms of transparency since all ground-based wave observations are restricted by transmission losses, mainly due to broadband extinction from tropospheric H2O and O2. Only extremely dry sites like Mauna Kea/Hawaii, the ALMA site of Chajnantor or Antarctica allow to access atmospheric windows in the spectral range above ~800 GHz. With the successfull start of SOFIA (Stratopsheric Observatory for Far-Infrared Astronomy), the frequency range up to a few THz is now open for observations.

We show here tropospheric transmission curves for existing earth-bound observatories, possible future sites, as well as airborne observatories or balloon experiments in the frequency range 0-2000 GHz (some sites up to 10000 GHz), calculated by the forward- and inversion model MOLIERE-5 (Microwave Observation LIne Estimation and REtrieval, Urban et al. 2004, J. Quant. Spectros. Radiat. Transfer 83,529). We present models for different values of precipitable water vapour (pwv), typically between 0.1 mm and 1 mm.

Details of the model as well as information on the observatories can be found in Schneider, Urban & Baron 2009, Planetary and Space Science, Vol. 57, Issue 12, p. 1419-1433 (see also this preprint). A summary describes the main features of the model and its parameters. 

MOLIERE was used for site testing in Antarctica:
"Site testing for submillimetre astronomy at Dome C in Antarctica",
Tremblin P., Minier V., Schneider N., et al.,  2011, A&A, 535, 112 

All plots and data files can be freely used if they are cited using the paper reference (Schneider, Urban & Baron, 2009) and/or the website.

Please contact N. Schneider for models at other geographical locations and/or other values of pwv. All authors can be contacted for further details and questions concerning the models and MOLIERE.


A list of radiotelescopes working in the (sub)mm-wavelengths range is given in this table. Sites where we performed model calculations are underlaid in red.

Telescope/Site Location latitude/longitude altitude [m] contact
European Sites

Metsahovi Kylmala/Finland 24d 23m E, 60d 13m N 60
OSO Onsala/Sweden 11d 55m E, 57d 23m N 23
IRAM Sierra Nevada/Spain 3d 23m W, 37d 4m N 2920

Chilenian Sites

NANTEN2 Pampa la Bola/Chile 67d 42m W, 22d58m S 4860
ASTE Pampa la Bola/Chile 67d 45m W, 22d58m S 4860
APEX Chajnantor/Chile 67d 42m W, 23d00m S 5105
ALMA Chajnantor/Chile 67d 42m W, 23d00m S 5105
CCAT Cerro Chajnantor/Chile 66d 44m W, 22d 59m S 5612

Hawaiian Sites

CSO Mauna Kea/Hawaii 155d 28m W, 19d 49m N 4092
JCMT Mauna Kea/Hawaii 155d 28m W, 19d 49m N 4092

US Sites

CfA Cambridge/USA 74d 00m W, 40d 42m N 6
SMT Mt. Graham/USA 109d 53m W, 32d 42m N 3186
KP12 Kitt Peak/USA 111d 37m W, 31d 57m N 1914


DOME-C Concordia-Station/Antarctica 123d 20m E, 75d 6m S 3233
DOME-A Dome Argus/Antarctica 77d 21m W, 80d 22m S 4093
DOME-F Dome Fuji/Antarctica 39d 42m E, 77d 19m S 3810
SPT South Pole/Antarctica 180d W, 90d S 2835


SRAO Seoul/Korea 37d 27m E, 126d 57m S 181
Qinghai Delingha/China 97d 33m E, 37d 22m N 3200
MOPRA Coonabarabran/Australia 31d 16m E, 149d 5m S 866
NRO Nobeyama/Japan 142d 43m E, 35d 56m N 1350
SOFIA Stratospheric Observatory aircraft 13000
balloon 35000