My approach as an atmospheric scientist is to apply my knowledge of the climate system to the Polar Regions of the Earth. My research has provided the unique opportunity to investigate weather and climate in both the Arctic and the Antarctic, to develop the high-performance computing skills necessary to model these challenging environments, and to evaluate these models both statistically and dynamically. Through this process, my appreciation for the interconnectedness of weather and climate and the impact that climate changes occurring in these regions have on other parts of the world has matured. Through my research, I have forged important collaborations with peers within my area of expertise including those of large-scale atmospheric dynamics, closely-related fields such as paleoclimatology, and I have worked with researchers from the National Center for Atmospheric Science, University of Toronto, and the European Centre for Medium-Range Weather Forecasts.
My research began in 2008 with the Polar Meteorology Group (PMG) at the Byrd Polar and Climate Research Center (BPCRC). Members of the PMG were already developing the polar version of the Weather Research and Forecasting model (Polar WRF), including updating the land surface, snow and sea-ice characteristics and modifying the physics parameterizations. I extended the results of these limited area domain simulations to a larger domain encompassing most of the Northern Hemisphere. This simulation included an Arctic-wide varying sea-ice albedo to better capture the seasonality and effects of melt water ponds on the total albedo. Another key aspect of my research was to select physics parameterizations best suited to the Arctic environment without diminishing the performance of the model in the mid-latitudes. To evaluate Polar WRF, I obtained and quality-controlled an abundant number of surface, upper air, precipitation, and radiation data. This work resulted in two peer-review publications in the Journal of Geophysical Research – Atmospheres on the performance of Polar WRF, one on the surface and upper-level variables and the other on the hydrologic cycle. My analysis of precipitation and clouds with Polar WRF helped identify (i) excessive convective precipitation in the model during summer over land, which was improved through a nudging technique of the atmospheric moisture, and (ii) a lack of cloud cover effects resulting in an overabundance of short-wave radiation at the surface. My research on Polar WRF has been used as an educational resource at the Columbus Zoo and Aquarium’s Polar Frontier and as guidance for improvements of twice-daily 96hr forecasts of the Arctic made available to the public by the PMG.
For my Doctoral Dissertation research, I examined the interaction between the tropics (the El Niño-Southern Oscillation) and high-southern latitude circulation variability (the Southern Annual Mode) to advance our understanding of climate across the Southern Hemisphere over the modern-observing period. I used various 12-month global sea surface conditions as lower boundary conditions in a global climate model, each representing various El Niño and La Niña events from the 1980s, 1990s, and 2000s, including the recently discovered El Niño flavors (the strength and location of maximum sea-surface temperature anomalies varies between the central and eastern tropical Pacific Ocean). This work has resulted in two peer-review publications in the Journal of Climate: one on idealized simulations of strong El Niño flavor events and the other based on observed El Niño flavors (provisionally accepted).
My current research encompasses several strands, with a focus on numerical modeling. I continue to evaluate the performance of the Arctic System Reanalysis (ASR), a gridded data set consisting of a blend of models and observations. ASR reprocesses historical data to reconstruct past weather over the Arctic region. I have focused on the evaluation of the hydrologic cycle, an extension of my earlier research with Polar WRF. My results have led directly to changes in the microphysics scheme used in Polar WRF for ASR resulting in an improved simulation of precipitation. The end product is a state-of-the-art synthesis of modeling and observations for 2000-2012 at three different horizontal resolutions (60 km, 30 km, and 15 km) that will allow researchers to assess and monitor the Arctic climate change that has been witnessed over this period. This work has resulted in one peer-reviewed publication in the Quarterly Journal of the Royal Meteorological Society, with a second submission forthcoming.
As a result of my modeling work on ENSO and the large-scale atmospheric circulation over the Southern Hemisphere, I have collaborated with researchers from the Ice Core Paleoclimatology Group at BPCRC to examine decadal relationships between tropical variability and the high-southern latitudes drawn from an ice core record on the Bruce Plateau on the Antarctic Peninsula. This work shows the relationships between climate indices that we most often use to make inferences of current climate are not static in time, limiting the ability to use the same relationships to evaluate climates of the past. This work has resulted in a peer-reviewed publication in the Journal of Climate (provisionally accepted). An upcoming model investigation will target the relationship between El Niño and the accumulation records derived from ice cores at opposite side of the Pacific Ocean (Peru and Himalayas).
Finally, I am working on a NASA project entitled Accurate Meteorology over Antarctica Based on GPS RO Profiles for GRACE Mass Balance Determination. This project aims to estimate more accurately the atmospheric mass signal over Antarctica so that it may be removed from the total mass variations measured by the Gravity Recovery and Climate Experiment (GRACE). This will be achieved by improving estimates of the surface pressure (PSFC) field over the Antarctic and the Southern Ocean by assimilating Global Positioning System (GPS) Radio Occultation (RO) profiles into Polar WRF and the WRF Data Assimilation system (WRFDA). This technique has already been shown to reduce monthly mean surface pressure biases across many locations in Antarctica, with distinct improvements over the high interior of Antarctica and in the favored Southern Ocean cyclogenesis region of Adélie Land. This project has a high societal impact factor, as the contribution of Antarctica to global sea-level rise depends on the respective changes in the amount of snow that it receives every year and the amount of ice released into the ocean at its margins. Improved measurements from GRACE will help constrain the errors associated with assessing ice loss from the continent.
My goal for future research is to maintain this modeling approach to climate science through evaluation and improvement of the current state-of-the-art model performance. The two-pronged approach to my climate studies thus far have allowed me to analyze the Arctic and Antarctic regional climate changes and their impacts on the larger-scale climate of Earth. For the Antarctic, climate modeling has improved tremendously over the last decade. Despite the advancement in our observing network over the Southern Hemisphere, there are still errors present in the reanalysis products used to validate our models. It is therefore necessary to improve these validation products by evaluating them against available field observations. For Antarctica, this should lead to better products used to improve global climate models as well as mesoscale models that are key tools to understanding the regional climate changes that are occurring over the continent.
For the Arctic, many researchers are beginning to uncover links between Arctic amplification and mid-latitude weather, such as extremes in temperature and precipitation events. I think there are several directions of research suited to my experience. First, my evaluation of atmosphere-ocean interaction using global climate models in the Southern Hemisphere can be applied to the broad impacts of the changing Arctic on large-scale global climate as well. This includes understanding and quantifying how the changing landscape (more open water, less frozen ground) contributes to changes in mid-latitude weather through links with the jet stream and other atmospheric dynamics. Second, I would like to extend my regional modeling to localized phenomenon such as the development of polar lows and how climate change in the Arctic, particularly the loss of sea ice, contributes to their development and trends. Finally, my experience and collaboration with ASR is an advantage for future research in the Arctic. ASR is an important addition to the existing repertoire of observations and reanalyses and is well suited to aid researchers in understanding the sea-ice decline and links to mid-latitude weather due to its superb sea-ice and Arctic land surface descriptions. In all of these research strands, I would like to apply analytical approaches that are well suited to large and complex data sets in order to understand further linkages between the Polar Regions and the rest of the world.
Lastly, collaborators and I have recently submitted a National Science Foundation (NSF) Exploratory Pathways proposal under the Advancing Informal STEM Learning program solicitation. This project aims to develop an interactive, intuitive, and visually appealing web application that will allow users to visualize current and past conditions of our planet’s atmosphere and oceans. The highlight of this endeavor is that our web application will generate interest and excitement among youth and young adults in the informal STEM environments, which are equally important for teaching. With success, subsequent work will adapt this visual application to formal learning settings as well under instructor-led question-based inquiry in order to improve scientific reasoning in the classroom. Funding from NASA, NOAA, and the NSF is predicated on proposals having a strong broader impact component. Therefore, outreach to community is critical for both a faculty member’s service contribution but also for securing funding from federal agencies for their research initiatives.