mm/submm site properties. RAChamberlin, CSO. May 3, 2004.1

South Pole Site Characteristics

Altitude: 2,800m (9,300 ft)Surface pressure: 650-680 mbAverage winter time temperature: -58 C (-72F)Average winter time windspeed: 6m/s (12 kts)Peak recorded windspeed: 22m/s (45 kts)Median winter time precipitable water vapor column: 0.28mmDeep inversion layer is common in winter

mm/submm site properties. RAChamberlin, CSO. May 3, 2004.2

Raw data from May 17, 1995 Radiosonde ascent

mm/submm site properties. RAChamberlin, CSO. May 3, 2004.3

Water Vapor Column Annual Cycle

Ref: Chamberlin, R. A. 2001, JGR-Atmos. 106, 20101

From RH indications From T indications assuming saturation

Data averaged from years 1961-1999

mm/submm site properties. RAChamberlin, CSO. May 3, 2004.4

Ref: Lane, A.P. 1998, in ASP Conf. Ser. 141, 289

Water vapor column from three submm-sites

mm/submm site properties. RAChamberlin, CSO. May 3, 2004.5

Tsky(K) = T0 + h*Tatm(1-exp(-to*Airmass))

Opacity from skydips (492GHz)

Ref: Chamberlin, R.A., Lane A. P., Stark, A. A. 1997, ApJ, 476, 428

Increasing Water

Vapor

mm/submm site properties. RAChamberlin, CSO. May 3, 2004.6

Comparison of water vapor column to opacity

Ref: Chamberlin, R. A. 2002, in ASP Conf Ser. 266, 172

Winter time interannual variation

mm/submm site properties. RAChamberlin, CSO. May 3, 2004.7 Ref: Radford S. J. & Chamberlin, R. A. 2000, ALMA Memo 334.1

Comparison of mm-wave opacity at three sites (225 GHz)

Cum

ulat

ive

dist

ribut

ion

mm/submm site properties. RAChamberlin, CSO. May 3, 2004.8

Comparison of submm-wave opacity at three sites (~860GHz)

Ref: Peterson J. B, Radford, S. J., et al. 2003, PASP, 115, 383

mm/submm site properties. RAChamberlin, CSO. May 3, 2004.9 Ref: Peterson J. B, Radford, S. J., et al. 2003, PASP, 115, 383

Comparison of submm-wave opacity stability at three sites (860 GHz)

mm/submm site properties. RAChamberlin, CSO. May 3, 2004.10

Ref: Chamberlin, R. A., et al. 2003, in Proc. of SPIE 4885, 609 Chamberlin, R. A., Martin, C. L. 2003, in Proc of AMOS, MEDB, Kihei, Maui, HI 96753

THz atmospheric transmission