Colorado Snow Study April 2015

In early April, Prof. Andrew Ault, Dr. Jessica Axson, and graduate student Hongru Shen from the Ault lab along with Dr. Jessie Creamean from NOAA, Boulder set out to Silverton Colorado for a short field study to collect snow and aerosol samples from a remote site in the San Juan Mountains of Colorado to examine dust deposition in the area. 

Google Map showing Silverton, CO and the Swamp Angel Sampling Site in the San Juan Mountains. 

April 2^nd: After arriving in Silverton the night before, the four of us set to out meet with Chris Landry and Jay Wlez from the Center for Snow & Avalanche Studies (CSAS; http://www.snowstudies.org) to trek out to the Swamp Angel Study Plot. To get to the site, we had to use snow shoes and carry in the instrument and supplies. The stunning location was surrounded by mountain ridges, including Red Mountain and Trico Peak.

Prof. Ault and Hongru Shen starting their trek to the sampling site for set up. 

Dr. Creamean, Jay Welz, and Chris Landry at the Swamp Angel Site

To collect aerosols, we used a 3 stage impactor with three different size cuts at <700 nm, 700 nm – 2.5 mm, and 2.5 mm<.  The impactor was run on battery power to avoid aerosol production and was kept safe from weather in an metal enclosure. 

Impactor at the sampling site.

For each night sampling, the instrument was strapped to the platform for stability (Show in picture are Prof. Ault, Dr. Axson and Hongru Shen). 

April 3^rd : To sample during the day and night, we changed samples every morning around 9:00-10:00 and again at 16:00-16:30.  Andy and Jessie head off to the airport, with Hongru and I remaining to collect 2 more days of sampling. We believe over Thursday night that we may have had a small dust event, evident by the loading on our top stage (2 um<) the following morning.

Sampling stage 1 (2.5 um<) after dust event. 

April 4^th: For the next two days of sampling, there was no visible loading on the top stage, but very small and still visible loading on the bottom two stages. Snow samples were collected all three days for offline analysis using IC and NTA.

April 5^th:  After packaging and shipping all of our equipment, Dr. Axson and Hongru Shen traveled back to Ann Arbor. We both enjoyed the beautiful mountain views from the flight from Durango to Denver.

Image of the Rocky Mountains on flight from Durango to Denver Colorado.