About the Project
Overview:
Snowpacks emit many chemical species to the overlying atmosphere, which affect air composition, chemistry and even climate. One example is the nitrogen oxides NO and NO2, which alter concentrations of ozone (O3), a pollutant and greenhouse gas, and the hydroxyl radical (OH), which is responsible for the removal of many other atmospheric pollutants. Changes in O3 can influence regional energy balance and climate, whereas OH controls levels of the greenhouse gas methane – as up to 40% of the Earth’s land surface is covered seasonally by snow or ice, these processes can have a substantial impact. Nitrous acid gas (HONO) is a particularly reactive nitrogen species, related to NO and NO2, which has been observed previously at surprisingly high levels in air above snow, suggesting a large snowpack source may be present. The aim of this project is to quantify the HONO snow source at the BAS Halley Research Station in Antarctica (75ºS) in summer.
The project will use a new HONO monitor to measure atmospheric HONO concentrations and emissions at Halley, and to perform lab experiments under controlled conditions using snow samples to investigate HONO formation. The data will be used together with an air-snow model to assess the importance of HONO for atmospheric composition above snow, and to improve global chemistry climate models. The project will be based much of the time at BAS/Cambridge and will be supervised by Dr Bloss (Birmingham, www.atmos.bham.ac.uk) and Dr Frey (BAS, http://www.antarctica.ac.uk).
Methodology:
The project will use a LOPAP HONO monitor, unique in the UK, to measure HONO production at the BAS Halley Research Station in Antarctica, and in the laboratory in the UK. A range of other (established) atmospheric measurement instruments (e.g. for NOx, O3, and physical / meteorological factors such as illumination levels) will also be used. Field experiments will take place at the Halley station over a summer season (November – February), following extensive training in the UK. Complementary laboratory studies using snowblock samples will take place in the British Antarctic Survey cold-room facilities in Cambridge.
Training and skills:
CENTA students will attend 45 days training throughout their PhD including a 10 day placement. In the first year, students will be trained as a single cohort on environmental science, research methods and core skills. Throughout the PhD, training will progress from core skills sets to master classes specific to the student’s projects and themes.
Full training in the specific instrumental techniques and modelling tools will be provided, with day-to-day help and guidance available from members of both research groups. Ahead of measurements at Halley, the candidate will assist with fieldwork, including use of the LOPAP instrument, at other locations. Full training for fieldwork at Halley will be provided by BAS. The candidate will be trained in an interdisciplinary environment, both in Birmingham and Cambridge. They will be encouraged to attend the NERC NCAS Atmospheric Science training course, and supported in preparing results for publication in peer-reviewed journals and at national / international conferences.
Partners and collaboration:
This project is offered as a CASE award, as a collaboration between the University of Birmingham (Bloss) and the British Antarctic Survey in Cambridge (Frey); BAS will make an additional contribution to the researcher’s stipend. The student will be registered at Birmingham, but will spend substantial time at BAS in Cambridge for instrument training, and fieldwork training. Their summer field season will involve being away from the UK for ca. 4 months, including travel time to/from Halley. The supervisory team has substantial experience of working together in related projects previously, including field measurements at Halley.
Possible timeline:
Year 1: Training in use of the LOPAP HONO monitor (Birmingham), NOx monitors and other instruments (BAS). Participation in (other funded) fieldwork with the Birmingham group to gain further experience in HONO measurements. Attend NCAS Summer School. Preparation for Antarctic field campaign.
Year 2: Field measurements at Halley; initial analysis and development of model framework for result interpretation. Initial laboratory snowblock experiments at BAS.
Year 3: Data analysis and interpretation, using snowpack-boundary layer photochemical model; follow-up laboratory experiments / tests as necessary; presentation of results at international conference (e.g. EGU, Vienna or AGU, San Francisco); thesis preparation & viva.
References
Bloss, W. J. et al., Coupling of HOx, NOx and halogen chemistry in the Antarctic boundary layer, Atmos. Chem. Phys., 10, 10 187–10 209, 2010.
Legrand, M. et al., Large mixing ratios of atmospheric nitrous acid (HONO) at Concordia (East Antarctic plateau) in summer: a strong source from surface snow?, Atmos. Chem. Phys. Disc., 14, 11 749–11 785, 2014.
New perspectives on Air-Ice Chemical Interactions (AICI) Special Issue (2013) Eds. V. F. McNeill, E. Wolff, T. Bartels-Rausch, and H. Pfeiffenberger. Atmos. Chem. Phys. (http://www.atmos-chem-phys.net/special_issue275.html)
Air Ice Chemical Interactions (AICI) Special Issue (2007) Eds. P. Shepson, B. Sturges, and E. Wolff. Atmos Chem Phys. (http://www.atmos-chem-phys.net/special_issue80.html)