From soliver at nrao.edu  Tue Jun  1 15:44:38 2004
From: soliver at nrao.edu (Stacy Oliver)
Date: Tue, 1 Jun 2004 12:44:38 -0700
Subject: [asac][almanews] ALMA Memo 500 Released
Message-ID: <002401c44810$e9538ce0$2802a8c0@radler>

ALMA MEMO #500

Wind power spectrum near Chajnantor

S. Sakamoto (NAOJ), H. Ishizaki (NAOJ), K. Kohno (IoA, U. Tokyo) 

2004-05-20 

Keywords: site testing, wind, gust, pointing 

We present wind power spectral density up to ~ 1 Hz measured near Cerro
Chajnantor.
The power spectral density of variable component is represented by its
value around
0.1 Hz. Median values of the wind power spectral density are smaller
than those 
predicted by the Simiu model with a roughness length of 0.05m in most
cases. The
90-percentile values of the wind power spectral density are
approximately three 
times larger than the corresponding median values. The wind power
spectral density
is not a simple function of mean wind velocity, and sometimes shows
significant 
suppression after sunset. There exists no significant change of the wind
power
spectral density and roughness length that depend on the wind direction.
Agreement
of wind velocity measured at 8.0 m and 3.0 m above the surface within a
few 10% 
difference supports small roughness length (<< 0.5). The van der Hoven
spectrum 
extracted from long-term weather station data implies that the weather
system in 
this area is very stable and change of mean wind velocity (i.e.,
duration of gusty
conditions) is dominated by the diurnal cycle. 

View a pdf version of ALMA Memo #500. 
http://www.alma.nrao.edu/memos/html-memos/alma500/memo500.pdf

_______________________________________________
Almanews mailing list
Almanews at listmgr.cv.nrao.edu
http://listmgr.cv.nrao.edu/mailman/listinfo/almanews


From soliver at nrao.edu  Mon Jun 14 17:01:22 2004
From: soliver at nrao.edu (Stacy Oliver)
Date: Mon, 14 Jun 2004 14:01:22 -0700
Subject: [asac][almanews] ALMA Memo 501 Released
Message-ID: <003701c45252$bfbd0bd0$85dbc5ce@radler>

ALMA Memo # 501

Estimation of ALMA Data Rate 

R. Lucas (IRAM), J. Richer (MRAO), D. Shepherd (NRAO),
L. Testi (Osservatorio Astrofisico di Arcetri),
M. Wright (BIMA), C. Wilson (McMaster University)

2004-06-07

Keywords: Computing, Data Rate 

In order to assess more firmly the estimated data rates on which
The ALMA Computing IPT has based the design of software and hardware,
the SSR has calculated the data rate for a sample of programmes in
the DRSP prepared by the ALMA Science IPT. Due to the limitations
in the process, the results are lower limits to the required data
rates, which are compatible with the present ALMA specifications. 

View a pdf version of ALMA Memo #501. 
http://www.alma.nrao.edu/memos/html-memos/alma501/memo501.pdf

_______________________________________________
Almanews mailing list
Almanews at listmgr.cv.nrao.edu
http://listmgr.cv.nrao.edu/mailman/listinfo/almanews