Another strategy is to use a sequential
sampler. The one shown in the auxiliary materials of the reference below
is fitted with three heaters and can collect 96 sequential snow (or surface
water or groundwater samples) at an interval as short as 10 minutes.
Two collectors have been collecting
precipitation samples in Northern California this last week, and two more
will be set up this coming week.
Coplen, T. B., Neiman, P.J., White,
A.B., Landwehr, J.M., Ralph, F.M., and Dettinger, M.D., 2008, Extreme changes
in stable hydrogen isotopes and precipitation characteristics in a landfalling
Pacific storm: Geophysical Research Letters, v. 35, L21808, doi:10.1029/2008GL035481.
Ty
Tyler B. Coplen
U.S. Geological Survey
431 National Center
Reston, VA 20192
Tel: +1 703-648-5862
Email: [log in to unmask]
We collect snow routinely for isotope analysis (originally on a mass
spec, now on the Picarro). Our field guy collects fresh snow weekly
from flat platforms (usually just plywood on a stand in the open)
into a 3" diameter jar with a tight lid. He brushes off the
rest of
the snow so the platform only collects fresh snow. The sample is
put
in a refrigerator to thaw overnight and then poured into exetainer
vials and capped and put back into the refrigerator until
analysis. I use the exetainer vials because it has a tight-fitting
cap, and because I can fill it to the top to eliminate air
space. This method has worked well for the last 5 years. For
the
Picarro, be careful that the sample doesn't have any particles in it
that might foul the needle. You should be able to see anything that
would cause a problem. Taking the sample from the very top of the
exetainer works, but you could also filter the snow water into the
exetainer through quartz wool.
Any method that 1) only collects current snow, 2) keeps the snow
contained as it thaws and 3) keeps the melt water from evaporating
until analysis, should be fine.
I like snow. It's easy.
Lola.
.
At 01:22 AM 1/22/2010, you wrote:
>Hello,
>
>I will be collecting snow samples for water isotope analyses using
a
>Picarro instrument. I would appreciate information on what sort of
>sample vials to use and any additional information on snow sample
>collection techniques.
>
>Thank you,
>Anne
>
>************************************************
>Anne Nolin
>Landolt et Cie Chair for Sustainable Futures, Ecole Polytechnique
>Federale de Lausanne and
>Associate Professor, Department of Geosciences
>Wilkinson 104
>Oregon State University
>541-737-8051 (office)
>541-737-1200 (fax)
>http://www.geo.oregonstate.edu/people/faculty/nolina.htm
>[log in to unmask]
>skype: AnneNolin; 541-497-7213
>************************************************