Category: research

My current research

Poster at AGU

0800h: C41C-0540
Snowpack and Air Interactions of (Semi)volatile Organic Compounds at Alert, Nunavut
Kos, G (gregor.kos@mcgill.ca) and Ariya, PA (parisa.ariya@mcgill.ca), McGill University, Department of Atmospheric and Oceanic Sciences, 805 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada.

Eighteen different (semi)volatile organic compounds (halogenated, aromatic and oxygenates) were determined in surface snow (0-10~cm) together with concurrent measurements of surface air samples. Subsequently, atmosphere-snow interactions were investigated. Samples were collected in the Canadian Arctic (Alert, Nunavut; 82° 29′ 58″ N, 62° 20′ 05″ W) between May 22 and June 2, 2006 during the snowmelt and rising temperatures. Snow samples analysed on site using solid-phase micro-extraction with gas chromatography and flame ionisation detection (GC/FID) and air samples analysed after transfer to Montreal employing a home-built cryo-trap GC/FID system showed a drop in concentration below the detection limit for a number of compounds (e.g. trichloroethene, benzene) in snow on May 30 that corresponded to a sudden increase in ground ozone concentrations and a shift in the origin auf air masses passing the sampling location 72 hrs prior to the sampling event from polar to South-Westerly source regions. Additionally, the warming of the boundary layer and subsequently the snow pack was accompanied by a transformation from dendritic to highly metamorphous snow. Sorption coefficient were used for the estimation of acetone concentrations in snow from air data and vice versa and comparison with measured values showed discrepancies of up to 3 orders of magnitude, indicating highly non-equilibrium conditions. Attempts were made to evaluate the gas/snow interactions using several thermodynamic calculations, the results of which will be discussed.

Conferences coming up

I will be going and presenting to a few meetings in the coming weeks and months –

AGU Fall meeting 2009/San Francisco (December 2008)

  • I am not going myself, but my coauthor will be presenting a poster

Arctic Change Conference 2008/Quebec City (December 2008)

  • I will be giving a talk focusing on my snow work and volatile organic compounds in session T14.

CMOS Congress 2009/Halifax (June 2009)

  • I will be chairing a session on “Identification and Transformation of Organic and Inorganic Species in the Lower Atmosphere, Snow Pack and Connected Compartments”. More info to come, once the scientific programme is out.

News after quite a bit of silence

I have to say the past months have been extremely busy – although I am well prepared, teaching 250 students is quite time consuming, because anything else than lecture preparation takes considerably more time than teaching smaller classes. That includes office hours, email requests, exam marking,….

My research on the other hand keeps me busy as well. I co-authored a review on bioaerosols that was revised under quite a bit of pressure with the deadline coming up fast. With other manuscripts being out for review by co-authors or or journal editors this kept me quite busy! So – here in more detail:

Research

  • “VOC in Snow at Alert” manuscript finalised after long discussions with new ideas coming up after each review; currently with co-authors
  • “Bioaerosol” review submitted
  • Reviews for a “Snow & Bio-Photochemistry” manuscript are in
  • Reviews for a “VOC in snow analysis mansucript in the Quebec-Windsor Corridor” are in

Teaching

  • Assignment 1 corrected for my Analytical Chemistry class (80 students)
  • Midterms corrected for both classes (250 students)
  • Final exams are being prepared

So – no surprise I get so little time to continue writing my blog! 🙂

Data interpretation & comparison

Still busy comparing and interpreting my measurement data with 3rd party measurements – very interesting, but tedious as well. I have obtained ground ozone data from Alert that was recorded during my own measurement campaign and the data confirm the trend that I already observed with column ozone data:

There is a correlation between the depletion event that I observed for the measured VOC species in air and snow and sharply increasing ozone concentrations near ground: Another indicator that VOC in near surface snow contribute to atmospheric processes.

ICASS 2008

ICASS 2008
ICASS 2008

I was on the programme committee for a conference that took place last week and I chaired 2 sessions together with a colleague. Session 1 on ‘Environmental Analysis’ and session 2 on ‘Medical Applications’. It’s been a lot of fun and an interesting meeting. Participants were mostly from and around Montreal, i.e. regional with quite a few from Sudbury (so this is, what regional means in Canada ;). A few came from France, Vietnam and even Japan. Sadly, quite a few could not make it due to Visa problems!

Here is the link to the scientific programme!

Number crunching (again!)

An error in some of the plots of my data has forced me to do review all my data from scratch again. Somewhere in the process of transposing, copying & formatting my data an error occurred and some of my snow data ended up as air data.

I do not have tons of data, but enough to make things difficult, when it gets messed up. Since numbers are similar (though units are not) I did not easily recognise my mistake. Now everything should be fine again, but it took a while to re-calculate all concentrations (18 compounds, 7 days of monitoring, air & snow) and plot them again.

Here is, how things look like: Toluene concentrations in snow and air at Alert in May/June 2006! Note the depletion in snow and air on May 30, which I also observed for quite a few other compounds (though not for all). I currently investigate this event using my other data and model calculations.

Back from vacation

After a month of vacation in Europe I am well rested (?) and ready for new adventures. Quite a few things are about to change – first my full time contract at Concordia has expired. People I replaced are back from their respective sabbaticals and I am back to research.

For the next couple of months I will be doing research at McGill University in the Department of Atmospheric and Oceanic Sciences again. I have one more paper to finish, two are currently under review, so things are looking good. This does, however, not mean that I will be giving up teaching, since I will sign a part-time contract at Concordia and teach two lectures in the fall term (General Chemistry – a new lecture and Analytical Chemistry I again).

And of course my job search is on again … exciting times ahead!

Alert manuscript rolling

After finishing my outline I now work on the details of my Alert manuscript. Still not sure, if it is going to be one or two papers (or a series) since there is a lot of ground to cover. On the other hand I do not want to duplicate any information, so for the moment I work on a single manuscript. With the structure and most figures done – the content tested at conferences, writing is pretty smooth with an established framework.

I typeset the manuscript with LaTeX, using a simple text editor, which is now my favourite way of writing long texts. I draw figures in Plot a drawing program for the Mac – both are open source tools and excellent for scientific writing. For image editing (e.g. map preparation and sampling location marking) I use The Gimp (again, a port for the Mac).

Outlining the next manuscript

With 2 manuscripts under review I started outlining the next manuscript about my field trip to Alert. After several oral presentations and 2 posters one some aspects of my results the material has been under enough scrutiny that it can be written up.

Apart from the new data and a broad range of compounds (aromatic, oxygenated, halogenated) that I detected in Arctic air and snow I would like to focus on the transfer of species between air and snow by comparing my results with calculations using sorption coefficients. I would also like to use back-trajectory calculations again to assess the influence of the movement of air masses on VOC concentrations.

For presentation of the material I will use a few new plots that I tried for a few compounds on the posters, since they illustrate well the change of concentrations in both matrices (for a single compound at a time). With the wealth of data that I have available selecting suitable plots is a crucial task.