Snow Sampling Procedure

From WikiYoungIPY-UA

Overall Synopsis: The goals of this sampling procedure are: 1) To sample the snow without contamination 2) To check for contamination using field blanks before and after sampling. We are sampling snow cores throughout the depth of the snowpack so that we get a picture of the snow-season averaged deposition of chemicals to the snow. The samples will be melted under controlled laboratory conditions and the concentration (mass per volume of liquid water) of impurities will be determined. If we multiply the concentration by the snow water equivalent (SWE, in depth of water for the snowpack), we get the loading of impurities that will be deposited to the ground or lake upon snow melt. This loading is in mass per area of the ground or lake.

1) Prepare yourself for sampling. You should have the snow sampling kit, and a shovel to dig a pit. Dig a snowpit to the surface of the ground or lake ice surface.

Put on the snow sampling Tyvek suit. Then put on two sets of the gloves. If it is cold, you can wear thin liner gloves inside the plastic gloves. Open the vacuum-sealed plastic bag that contains the coring tube.

2) Measure the first field blank. Open the blue-capped tube labelled “Blank1”. This sample tube will receive the blank sample. Place the uncapped tube into the snow away from where you will take the sample. Now open a tube of ultrapure water and pour the water down the coring tube, directing the water output into “Blank1” sample tube. Contamination on the coring tube will now flow with the water into the “Blank1” sample. Some of the water will probably miss the “Blank1” sample, which is fine; just try to get 10-20 milliliters of water. When you run out of the water to pour in, the corer, lay the corer on the snow, and cap off the sample tube.

We will analyze this sample to determine how much contamination existed on the corer before you started the measurements.

3) Sample a core of snow. At the edge of your snowpit, probably about 6-8 inches back from the face, push the corer (sharp end down) into the snow down to the base. If the snow is too deep to get in the corer, simply go half way down, and then repeat to get the lower portion. Use the spatula to peel the face of the snow pit back to corer, then put it under the corer to keep the sample in the tube. Try to get as much of the snow pack as you can without contaminating the sample with dirt from the ground (not a problem on lake ice).

Open a core bottle and place it mouth down onto the core coupler. Then, remove the core from the snow pack and invert to transfer the snow into the core bottle. If the snow is hard, you will need to bounce the core bottle to shake the snow into the bottle. Measure the height of the snow pack where you took the core, and record this height in your records along with the sample bottle name.

4) Sample two more cores (to fill the three core bottles). If there are thinner or thicker regions of the snow pack, take cores from somewhere thin, somewhere thick, and an average spot. Record as much detail as possible regarding the snow condition where you sampled.

5) Now take another blank. The procedure is the same as step 2, but now the sample is “Blank2”. We will analyze this sample to determine how dirty the corer got during the measurements.

6) Pack up the samples and sampling kit and ship it all back to Fairbanks. The samples should remain frozen, so make sure that we are here to receive the samples before you ship them.