Research Interests
The Stanier Research Group has wide-ranging interests in atmospheric science, climate science, and air pollution.
Our main current projects focus on (1) health effects of atmospheric pollution, focusing on ultrafine particulate matter; (2) modeling of CO2, CO, carbonyl sulfide, and stable isotopes in the carbon cycle; and (3) chemistry and physics of ultrafine, nanosized, and nucleated atmospheric particles.
LINKS TO PROJECT MANAGEMENT WEBSITES
Our research portfolio includes atmospheric science problems motivated by both climate change and by human health. The investigations share a set of tools that we have developed in our lab and in collaborator labs. These include measurements such as Scanning Mobility Particle Sizing, the Dry-Ambient Aerosol Size Spectrometer technique for measurement aerosol water content, thermal and hygroscopic TDMA, and cloud condensation nuclei. This also includes (in collaboration with the Carmichael group) 3D chemical transport models that we apply to carbon cycle gases, gas phase pollutants, and aerosols. We also have developed box, 1D and 2D process models that combine dispersion, motor vehicle emissions, and new particle formation.
Many of our projects involve detailed data analysis at the interface between models and measurements. This is particularly true for carbon cycle gases, new particle formation, and organic aerosols. For example, to facilitate detailed data analysis of particle data, we have developed in house MATLAB-based software for ingesting and processing aerosol size distribution measurements. Through collaboration with the Carmichael group, we use state-of-the-art data assimilation tools including 4dvar adjoint modeling of pollution transport (e.g. CO2) and aerosol transport.
Through ongoing collaborations with UI researchers, we have begun to work on aspects of heterogeneous atmospheric chemistry (Grassian Group) and LIDAR measurement of boundary layer dynamics as it relates to carbon and pollutant transport (Eichinger Group).
Some photos and figures from our research are below. For the nuts and bolts (and possibly more up-to-date info), please see the publications page. It is our intention to improve this page to include introductory material on each of the atmospheric problems that we study -- the "what" and "why" of aerosol health effects, carbon cycle budgets, new particle formation, etc. But until that is done, I have tried to give detailed captions to some images below.
Gallery of Some Images and Figures from Our Research
Upward looking photo of the WKWB transmitter tower which is now (as of July 1, 2007) sampling CO2 and CO as part of the NOAA global monitoring network (station ID WBI -- for West Branch Iowa). Met stations can be seen sticking out to the left. There are three of them, one is all the way at the top, very difficult to make out. Carbon dioxide and carbon monoxide are continuously pumped down from the three levels of the tower and analyzed by continuous spectroscopic analyzers. The idea is that a network of sites like these provides the data for "top down" estimation of carbon fluxes, particularly those associated with forest regrowth and crop production. For more information, go to the NOAA global monitoring division website.
NASA DC-8 CO2 measurements CO2 along ICARTT DC-8 flight path on July, 20, 2004. These were the inspiration and data source for much of Elliott Campbell's thesis. These summertime flights offered a test of the models and carbon flux estimates that we combined to make atmospheric CO2 predictions. Measured values shown in top and bottom plots. Modeled CO2 is black line, bottom plot. Model-measurement agreement deteriorates at low altitudes over agricultural lands, indicating underestimate (and poor predictive ability) of crop CO2 drawdown in model.
Obvious to most folks... this is not from our research but rather from the Intergovernmental Panel on Climate Change (IPCC). This figure is from the "Summary for Policy Makers" of the Fourth Assessment Report work Working Group I (Climate Science Group). This figure is important to the motivation for our work. Our carbon cycle work is tied to the largest positive forcing (long-lived greenhouse gases). Our New Particle Formation research is motivated by the largest negative forcing -- the cloud albedo effect.
In the jargon, the source is IPCC 2007:WG1-AR4 SPM. Links to IPCC and to the Working Group 1 AR4 documents for download.
A cool picture taken by Alica Kalafut during the MILAGRO field campaign in Mexico City. We took our Dry-Ambient Aerosol Size Spectrometer to Mexico City and sampled at the T0 station. Greg Carmichael's group from the University of Iowa worked on forecasting for the field study, and Bill Eichinger's group did LIDAR measurements throught central mexico.
The main pieces of the dry-ambient aerosol size spectrometer awaiting tubing and wiring in building 32 in Mexico City, site T0.
Cover of JGR Special Issue showing corresponding between new particle formation (NPF) and aerosol composition. Aerosol composition data from Qi Zhang and Jose Luis Jimenez (University of Colorado) Link to special section of JGR here. New Particle Formation (NPF) is important as a source of atmospheric particles that can serve as cloud condensation nuclei. NPF occurs in both remote and polluted (including urban) environments. There is likely a large difference in the health effects between nucleated sulfate-organic particles and nanosized combustion particles. Tools for separating these particles and their health effects are needed.
Our aerosol sampling trailer at the Bondville Experimental Atmospheric Research Site near the University of Illinois. This was our first deployment. We sampled NPF events on 25% of the days, based on 21 days of sampling.
This collage shows part of our approach to New Particle Formation (NPF). These are predictions from a vertically-resolved aerosol dynamics model that includes sulfuric acid particle growth, and nucleation by binary and ternary mechanisms. The SO2, NH3 and meteorological parameters are extracted from the University of Iowa STEM model and from the MM5 met model. Here we contrast (on the left) predictions by a model sensitive to ammonia, with one that is not. On the right, we show the difference in the particle size distribution evolution at different elevations.
Regression result to determine the aerosol mass fraction (yield) of secondary organic aerosol with accurate temperature dependence and uncertainty bounds. These types of regressions are required to put secondary organic aerosols into Chemical Transport Models. Example is for alpha pinene ozonolysis but technique is general. See The Coupled Partitioning, Dilution, and Chemical Aging of Semivolatile Organics and other papers involving secondary organic aerosols in the publications page.
About 2% change in aerosol volume for every degree of heating or cooling. In a continuing collaboration with researchers at the Carnegie Mellon Center for Atmospheric Particle Studies, these are published results on the temperature sensitivity of SOA concentrations. Stanier, Pathak, et al. 2007.
Polystyrene Latex Spheres used for size calibration, SEM image. These are 1 micron calibration aerosols, imaged at the University of Iowa Central Microscopy Research Facility (CMRF).
Page maintained by C. Stanier