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Chajnantor Plateau

The Atacama Pathfinder Experiment (APEX) is an existing 12m radiotelescope situated at an altitude of 5105m on the plateau of Chajnantor in Chile where the future interferometer ALMA (Atacama Large Millimetre Array) is under construction. The figure indicates the two sites, as well as the sligthly lower (4865m) sites of NANTEN2 and ASTE.


Landsat image of the Atacama desert near San Pedro de Atacama. (Image courtesy of ESO/Cornell U.)

The following plot shows the transmission of the first decile (10 %, grey) and the three quartiles (25 % red, 50 % blue, 75 % green) of the pwv statistics between 2008 and 2010 extracted from the IASI satellite. 



The left plot shows the transmission in percent for values of pwv=0.3mm (grey), 0.6mm (red), and 1mm (blue) against frequency/wavelength for a frequency range 0-2000 GHz. The frequency resolution is 200 MHz. The right plot shows curves for pwv=0.1mm (grey), 0.2mm (red), and 0.3mm (blue). All models were calculated for winter conditions (temperature and pressure profiles from july).

0-2000 GHz

Zooms into some THz-windows at higher frequency resolution. All models are valid for pwv=0.2mm.
200 micron df=200 MHz 290 micron df=50 MHz 350 micron df=50 MHz 450 micron df=50 MHz






Gzipped-ascii-files of data in two-column format. First column: Frequency in GHz, second column: Transmission (to get opacity take -ln(transmission)). The frequency resolution (df) is indicated for each model.
Frequency [GHz] 0-2000 (df=200 MHz)
535-750 (df=50 MHz) 750-950 (df=50 MHz) 950-1110 (df=50 MHz) 1195-1670 (df=200 MHz)
pwv=0.1mm alma-0-2000-01




pwv=0.2mm alma-0-2000-02
alma-535-750-02 alma-750-950-02 alma-950-1110-02 alma-1195-1670-02
pwv=0.3mm alma-0-2000-03




pwv=0.4mm alma-0-2000-04




pwv=0.5mm alma-0-2000-05




pwv=0.6mm alma-0-2000-06




pwv=1mm alma-0-2000-1