Atmospheric & Environmental Physics Research Cluster

Project Description: The atmosphere has two major possibilities to clean itself: (1) by rainout of water soluble particles and gases, and (2) by oxidation reactions resulting in products with higher water solubility which can then be removed by rain. The most important oxidant in the lower atmosphere is the OH radical which is produced during daytime from sunlight in the presence of ozone and water vapour. My research group has achieved - for the first time worldwide - long-term measurements of OH concentrations in the coastal atmosphere which started in 2009 at our Mace Head research station near Carna, Connemara. We are using a highly sophisticated mass spectrometry method based on chemical ionisation of target molecules in conjunction with a broad range of supporting trace gas and aerosol measurement techniques. Our research contributes to better understand the changing composition of the atmosphere as a result of man-made pollution and global climate change. We have detected at least one unidentified oxidant species of similar importance to OH which may result from iodine emissions by seaweed indicating the potential importance of marine biology to the self-cleaning of the atmosphere. Currently, we are planning to extend our measurement programme in a major collaboration with the University of Bristol (UK) and the Research Center Jülich (Germany).

Project Description: The Environmental Protection Agency (EPA) has recently announced a research programme to establish a national survey of the presence of persistent organic pollutants (POPs) in electronic, vehicular, and construction waste in Ireland. Of particular importance are bromine containing substances which have been added to corresponding materials as flame retardants and which may constitute a significant health risk if leached into water systems by rain or other processes. In collaboration with the University of Bristol we have submitted a proposal to the EPA which is currently under review. We anticipate that it will be funded and research will begin in spring 2015. There will be a need for one PhD student to be engaged in field measurements at corresponding sites in Ireland and contributing to the data analysis and a final synthesis report to the EPA. The student will be trained and partially supervised by a postdoctoral fellow who has already strong expertise in this research area. We expect from the student a strong interest for environmental themes, practical engagement with measurement techniques, and basic knowledge of pollutant chemistry (a physics student can do this !). Co-supervision with Prof. Stuart Harrad (Univ. Birmingham, UK)

Project Description: Airborne Particulate Matter (PM) is internationally-acknowledged as a major environmental concern because of its known adverse impacts on human health, and since we spend approximately 89% of our time indoors, indoor PM deserves particular attention. The use of computational models in predicting indoor PM exposure, for individuals and population groups, has been well documented, but the accuracy of such predictions is limited by model input uncertainties, particularly with respect to building ventilation rates and combustion source emission rates. In this project, the latest probabilistic modelling technology will be refined, by providing accurate input data (currently non-existent), generated through experiment, on ventilation and combustion source emission rates. The refined model will then be used to provide, for the first time, accurate PM exposure estimates for occupants of a broad range of buildings who are subject to multiple PM sources. These results will benefit numerous stakeholders, e.g. policy makers, who wish to investigate whether reducing building ventilation rates (for reasons of energy conservation) will result in elevated PM concentrations indoors. In addition, the degree of protection afforded, for example, by staying inside a building during an atmospheric release of PM that is of a biological or radioactive nature can also be accurately assessed for the first time using this model

Project Description: In recent years there has been much emphasis on improving the energy performance of European buildings, this sector accounts for 40% of the total EU energy usage and is the main focus of the Energy Performance Buildings Directive (EPBD, 2002/91/EC; 2010/31/EU).

Energy efficient measures have some obvious direct health benefits such as increasing indoor temperatures and occupant comfort , however it is not clear how increased building air tightness will impact on levels of indoor air pollutants, such as particulate matter. In most developed countries the population is known to spend upward of 80% of their time within indoor environments as a result exposure indoors likely to play a significant role in human health.

The impacts of increasing the energy efficiency of buildings are largely positive; along with reducing energy use, helping to meet National and EU Energy targets, the building retrofit should improve indoor temperature, and reduce moisture, which in turn may improve mental and respiratory health of residents. However there are some concerns that increasing building air tightness may have a negative effect on indoor air quality (IAQ), which in turn could affect health. Drawing on the results from another EPA sponsored project on IAQ in energy efficient homes, this project proposes to evaluate the health benefits of energy efficient retrofits.

Project Description: NUIG/CCAPS, at Mace Head, possess the most fruitful database of continuous measurements of aerosol physics, chemistry, hygroscopicity, scattering and activation into cloud condensation nuclei. In addition, there exists a temporally-parallel data base of cloud properties which is to be combined with the aerosol properties to develop an aerosol-cloud-interaction parameterisation.

Key Words: remote sensing; cloud microphysics; aerosol; RADAR; LIDAR.

Project Description: NUIG/CCAPS, at Mace Head, deploy a CLOUDNET suite of ground-based meteorological, aerosol and cloud remote sensors (microwave humidity/temperature, aerosol LIDAR, and cloud RADAR profilers) and, combining these sensors in a synergetic manner, have been at the forefront of development of cloud microphysical parameters relevant to aerosol-cloud-climate interactions. This PhD involves further development of the retrievals to multiple clouds types and will contribute to reducing the uncertainty in aerosol-cloud-climate interactions.

Key Words: remote sensing; cloud microphysics; RADAR; LIDAR.

Project Description: Air pollution has a direct impact on climate by producing regional haze layers and clouds which scatter and reflect incoming solar radiation. Global diming observed worldwide since the middle of last century turning into global brightening exacerbating global warming. A combined analysis of the air quality trends with those of global radiation across EMEP and IMPROVE networks will highlight future climate changes due to aerosol effects.

Key Words: Air quality, global radiation, cloud, climate forcing.

Project Description: Primary marine organic matter is a unique atmospheric constituent affecting aerosol physico-chemical properties, cloud condensation nuclei and cloud formation in marine atmosphere. Tightly related to biological activity at the ocean surface, primary organic matter in sea spray undergo chemical evolution in the atmosphere affecting its volatility, hygroscopicity and oxidation state. NUIG/CCAPS, at Mace Head, developed a simulated system to study transformation and evolution of primary marine organic matter produced at the lowest trophic level.

Key Words: remote sensing; cloud microphysics; aerosol; RADAR; LIDAR.

Project Description: North-East Atlantic region is a unique natural laboratory for exploring air quality on a regional as well as hemispheric scale. NUIG/CCAPS, at Mace Head, possess the most fruitful database of continuous measurements of air quality. Langrangian approach to air pollution network data and the use of isotopic methods offer unparalleled tools for establishing sources and sinks of particulate air pollution and the trans-boundary pollution budget.

Key Words: Regional Air Quality, trans-boundary air pollution.

Project Description: This project would aim at parameterising the CCN activation efficiency as a function of particle hygroscopicity, composition and size, deploying the long term concurrent measurements of aerosol chemical and physical properties, such as size segregated chemical composition, particle size distribution, hygroscopisity and particle activation to cloud condensation nucleus (CCN). Existing data sets would be used along with the new measurements.

Key Words: Aerosol Mass Spectrometry; CCN activation; aerosol hygroscopic growth.

Project Description: Long term high time resolution aerosol chemical composition measurements at Mace Head capacitate a development of an advanced primary marine organic – chlorophyll parameterization for deployment in the sea spray source function, used for the climate modelling. The project would aim at identifying and quantifying the primary marine organics by combining the ambient marine aerosol measurements obtained by Aerosol Mass Spectrometry (AMS) and source apportionment techniques with laboratory experiments, which then would be used for the development of the parameterization.

Key Words: Aerosol Mass Spectrometry; marine organics; sea spray aerosol.

Project Description: NUIG/CCAPS will deploy the state of the art Weather Research and Forecasting model with coupled Chemistry (WRF-Chem) in conjunction with extensive in-situ measurements from its Global Atmosphere Watch monitoring station to quantify the effect of trans-boundary air pollution for a range of key air quality indicators at both a national and regional level and how this may change under future emission scenarios.

Key Words: air quality, modelling, trans-boundary, climate change

Project Description: NUIG/CCAPS will deploy the state of the art Weather Research and Forecasting model with coupled Chemistry (WRF-Chem) for modelling of the emission, transport, dispersion, aggregation, chemical processing and loss mechanisms of SO2 and ash from volcanic eruptions. The model will be validated with satellite retrieval data and ground based in-situ measurements and operational forecast capabilities will be developed.

Key Words: Volcano, SO2, modelling, ash emissions

Project Description: NUIG/CCAPS, at Mace Head, deploy a CLOUDNET suite of ground-based meteorological, aerosol and cloud remote sensors (microwave humidity/temperature, aerosol LIDAR, and cloud RADAR profilers) and, combining these sensors in a synergetic manner, have been at the forefront of development of cloud microphysical parameters relevant to aerosol-cloud-climate interactions. This PhD involves further development of the retrievals to multiple clouds types and will contribute to reducing the uncertainty in aerosol-cloud-climate interactions.

Key Words: remote sensing; cloud microphysics; RADAR; LIDAR.

Project Description: Investigation of physical processes responsible for the spreading of oil products in ice free and ice covered waters will help to develop technology for the remediation of Arctic environment and reduction of environmental risks in the Arctic associated with oil contamination.

Surface waves propagating from clean waters into areas covered by a flexible surface cover, e.g. an oil slick or sea ice, will become (a) heavily damped due to frictional forces. The air-sea momentum fluxes that force the oceanic mean flows (b) depend on the waves and hence these will also be affected by the surface cover. In the wave damping process the waves exert a stress on the surface cover, hence (c) inducing mean flows that bring about changes in the surface cover properties, which will in turn impact on (a) the wave damping. Very few studies have considered the full coupling between the waves, the momentum fluxes, and the mean flow, and experimental evidence to validate components of such theories is lacking.

The primary aims of the proposed project are to determine:

• how different surface covers will damp waves,
• how these surface covers impact on the air-sea fluxes,
• how much of the lost wave momentum will lead to increased mean flow,
• how the near surface turbulence and effective viscosity are affected by the covers.

Project Description: Present area, thickness and mobility of the Arctic ice cover is a manifestation of climate change with huge implications for ocean circulation, global weather, economics and governance. The seasonal sea ice cycle drives large variations in the transport of heat, buoyancy, and the compounds that fuel the biogeochemical cycles. The role of ocean, either directly or through feedback mechanisms, is under debate.

Estimates of oceanic heat fluxes are dwarfed by large uncertainties, mainly due to lack of observations of sufficient quality. It is, however, beyond doubt that the circulation patterns of the Atlantic Water layer in the Arctic Ocean and the presence of a cold halocline layer “protecting” the ice cover are sensitive to diapycnal mixing rates in the ocean. Identifying principal mechanisms for ocean heat transport processes and quantifying their contribution are crucial for the Arctic heat budget as well as global scale weather and climate. NICE will contribute in better constraining climate models and reducing the errorbars on ocean heat fluxes. It is not the aim of NICE to produce new parameterizations for climate models – a task for a larger coordinated project – however, the knowledge gained and data collected will pave the way for observationbased parameterizations.

Project Description: One of the most important issues facing society is how the future water cycle may be affected by a changing climate. The exponential increase in the vapour-carrying capacity of the atmosphere with temperature implies that changes could be severe. The distribution of rainfall, and associated floods and droughts, is arguably the single most societally-relevant aspect of climate change. Since the vast majority of the water cycle takes place over the oceans, it is clear that changes in water cycle over the ocean must be monitored. There are clearly significant technical challenges associated with measuring precipitation over the ocean. However, the recent launch of satellites capable of sensing sea surface salinity (SSS), such as ESA’s Soil Moisture Ocean Salinity (SMOS) mission, offer a potential way forward. Since SSS is largely determined by the local balance between evaporation and precipitation, it is anticipated that changes in SSS, as measured by SMOS, may be used as a proxy for changes in the water cycle over the ocean. A potential problem for this methodology is related to the fact that SMOS only samples the upper centimetre of the water column. In areas where strong near-surface salinity gradients exist, changes in the upper centimetre may not be representative of those in the upper several metres of the ocean. There remains a pressing need to investigate the magnitudes of these gradients, under different mixing regimes. The field component of the proposed project is strongly associated with the Salinity Processes in the Upper-ocean Regional Study 2 (SPURS2) program. This investigation will take place in the eastern equatorial Pacific Ocean in late 2015. The low salinities in this region are driven by some of the largest rainfall rates on the planet. This high rainfall plays a key role in determining the upper-ocean stratification, in particular by forming small freshwater “puddles” which can cover the upper several metres of the water column and suppress vertical mixing. The overarching goal of this project is two-fold. Firstly, we will seek to understand and quantify how strong salinity gradients are. Secondly, we will directly compare SMOS estimates of SSS with in-situ measurements. Microstructure profilers are a common method of measuring salinity structure in the upper ocean. Unfortunately, almost all of these operate in a downward profiling mode. A consequence of this is that they are not able to observe the crucial upper 5-10 metres, which is required in order to validate SMOS measurements. In order to capture this region, an upwardly rising profiler must instead be used. The Air-Sea Interaction Profiler (ASIP) is one such profiler. ASIP is extremely well-suited to observing the upper ocean, particularly in its almost unique ability to sample the upper several metres of the water column in high-resolution. This will allow us to understand the salinity structure in this under-sampled region, and allow for a proper validation of SMOS. It is anticipated that this comparison will allow for potential biases in SMOS to be identified, and permit corrections to be ultimately developed.