- Akinsola, A. A., G. J. Kooperman, W. M. Hannah, K. A. Reed, A. G. Pendergrass, and W.-C. Hsu, 2023: Evaluation of present-day extreme precipitation over the United States: an inter-comparison of convection and dynamic permitting configurations of E3SMv1, Env. Res. Lett., accepted.
- Hsu, W.-C., G. J. Kooperman, W. M. Hannah, K. A. Reed, A. A. Akinsanola, A. Pendergrass, 2023: Evaluating Mesoscale Convection Systems Over the US in Conventional and Multiscale Modeling Framework Configurations of E3SMv1. J. Geo. Res., 128, e2023JD038740.
- Lee, J. M., C. Tao, W. M. Hannah, S. Xie, and D. C. Bader, 2023: Assessment of warm and dry bias over ARM SGP site in E3SMv2 and E3SM-MMF,. J. Atmos. Sci., accepted.
- Yu, S., Hannah, W. M., Peng, L., Bhouri, M. A., Gupta, R., Lin, J., … Khairoutdinov, M. … & Pritchard, M. S. (2023). ClimSim: An open large-scale dataset for training high-resolution physics emulators in hybrid multi-scale climate simulators. arXiv preprint arXiv:2306.08754.
- 2023). Understanding precipitation bias sensitivities in E3SM-multi-scale modeling framework from a dilution framework, J. Adv. Model. Earth Sys., 15, e2022MS003460. , , , & (
- Reed, K. A., Stansfield, A. M., Hsu, W.-C., Kooperman, G. J., Akinsanola, A. A., Hannah, W. M., et al. (2023). Evaluating the simulation of CONUS precipitation by storm type in E3SM. Geophysical Research Letters, 50, e2022GL102409.
- 2022). The DOE E3SM Model version 2: Overview of the physical model and initial model evaluation, J. Adv. Model. Earth Sys., 14, e2022MS003156, https://doi.org/10.1029/2022MS003156. , , , , , , et al. (
- 2022: Convective momentum transport and its impact on the Madden-Julian Oscillation in E3SM-MMF, J. Adv. Model. Earth Sys., 14, e2022MS003206. , , &
- Giorgetta, M. A., Sawyer, W., Lapillonne, X., Adamidis, P., Alexeev, D., Clément, V., Dietlicher, R., Engels, J. F., Esch, M., Franke, H., Frauen, C., Hannah, W. M., Hillman, B. R., Kornblueh, L., Marti, P., Norman, M. R., Pincus, R., Rast, S., Reinert, D., Schnur, R., Schulzweida, U., and Stevens, B., 2022: The ICON-A model for direct QBO simulations on GPUs, Geosci. Model Dev., 15, 6985–7016.
- Hannah, W. M., K. G. Pressel, 2022: Transporting CRM Variance in a Multiscale Modelling Framework, Geosci. Model Dev., 15, 8999–9013.
- Hannah, W. M., K. G. Pressel, M. Ovchinnikov, G. S. Elsaesser, 2022: Checkerboard Patterns in E3SMv2 and E3SM-MMFv2, Geosci. Model Dev., 15, 6243–6257.
- Peng, L., M. S. Pritchard, W. M. Hannah, P. N. Blossey, C. S. Bretherton, 2022: Load-balancing intense physics calculations to embed regionalized high-resolution cloud resolving models in the E3SM and CESM climate models, J. Adv. Model. Earth Sys., 14, e2021MS002841.
- 2022: Assessing two approaches for enhancing the range of simulated scales in the E3SMv1 and the impact on the character of hourly US precipitation. Geophysical Research Letters, 49, e2021GL096717. , , , , &
- Hannah, W. M., A. M. Bradley, O. Guba, Q. Tang, J.-C. Golaz, and J. Wolfe, 2021: Separating Physics and Dynamics grids for Improved Computational Efficiency in Spectral Element Earth System Models. J. Adv. Model. Earth Sys., 13, e2020MS002419.
- Norman. M. R., D. Bader, C. Eldred, W. M. Hannah, B. Hillman, C. R. Jones, J. M. Lee, L. R. Leung, I. Lyngaas, K. G. Pressel, S. Sreepathi, M. A. Taylor, and X. Yuan, 2020: Unprecedented Cloud Resolution in a GPU-Enabled Full-Physics Atmospheric Climate Simulation on OLCF’s Summit Supercomputer, Int. J. of High Perf. Comp. App., doi:10.1177/10943420211027539.
- Akintomide, A., G. Kooperman, K. Reed, A. Pendergrass, W. M. Hannah, 2020: Projected changes in seasonal precipitation extremes over the United States in CMIP6 simulations, Env. Res. Lett., 15, 104078.
- Akintomide, A., G. Kooperman, A. Pendergrass, W. M. Hannah, K. Reed, 2020: Seasonal representation of extreme precipitation indices over the United States in CMIP6 present-day simulations, Env. Res. Lett., 15, 094003.
- Morrison, H., J. M. Peters, A. C. Varble, S. Giangrande, W. M. Hannah, 2020: Thermal chains and entrainment in cumulus updrafts, Part 2: Analysis of idealized simulations. J. Atmos. Sci., 77, 3661-3681.
- Morrison, H., J. M. Peters, A. C. Varble, S. Giangrande, W. M. Hannah, 2020: Thermal chains and entrainment in cumulus updrafts, Part 1: Theoretical description. J. Atmos. Sci., 77, 3637-3660.
- Hannah, W. M., C. R. Jones, B. R. Hillman, M. R. Norman, M. A. Taylor, D. A. Bader, L. R. Leung, M. S. Pritchard, M. D. Branson, G. Lin, K. G. Pressel, and J. M. Lee, 2020: Initial Results from the Super-Parameterized E3SM. J. Adv. Model. Earth Sys., 12, e2019MS001863.
- Peters, J. M., W. M. Hannah, H. Morrison, 2019: The influence of vertical shear on moist thermals. J. Atmos. Sci., 76, 1645–1659.
- Zeng, X., D. Klocke, B.J. Shipway, M.S. Singh, I. Sandu, W. M. Hannah, P. Bogenschutz, Y. Zhang, H. Morrison, M. Pritchard, and C. Rio, 2018: Future Community Efforts in Understanding and Modeling Atmospheric Processes. Bull. Amer. Meteor. Soc., 99, ES159–ES162.
- Mapes,B. E., E. S. Chung, W. M. Hannah, H. Masunaga, A. J. Wimmers, C. S. Velden, 2018: The Meandering Margin of the Meteorological Moist Tropics. Geophys. Res. Lett., 45, 1177– 1184.
- Singh, M. S., Z. Kuang, E. D. Maloney, W. M. Hannah, B. O. Wolding, 2017: Increasing potential for intense tropical and subtropical thunderstorms under global warming. Proc. Natl. Acad. Sci., 114, 11657–11662.
- Hannah, W. M., 2017: Entrainment vs. Dilution in Tropical Deep Convection. J. Atmos. Sci., 74, 3725–3747.
- Hannah, W. M., and A. Aiyyer, 2017: Reduced African Easterly Wave Activity with Quadrupled CO2 in the Super-Parameterized CESM. J. Climate, 30, 8253–8274.
- Russell, J. O., A. Aiyyer, J. D. White, and W. M. Hannah, 2017: Revisiting the Connection Between African Easterly Waves and Atlantic Tropical Cyclogenesis. Geophys. Res. Lett., 43.
- Hannah, W. M., B. E. Mapes, and G. S. Elsaesser, 2016: A Lagrangian View of Moisture Dynamics During DYNAMO. J. Atmos. Sci., 73, 1967-1985.
- Hannah, W. M., E. D. Maloney, and M. S. Pritchard, 2015: Consequences of Systematic Model Drift in DYNAMO Hindcasts with SP-CAM and CAM5, J. Adv. Model. Earth Sys., 7, 1051–1074.
- Hannah, W. M., and E. D. Maloney, 2014: The moist static energy budget in NCAR CAM5 Hindcasts during DYNAMO, J. Adv. Model. Earth Sys., 6, 420-440.
- Hannah, W. M., and E. D. Maloney, 2011: The Role of Moisture-Convection Feedbacks in Simulating the Madden-Julian Oscillation, J. Climate, 24, 2754-2770.
- Maloney, E. D., A. H. Sobel, and W. M. Hannah, 2010: Intraseasonal Variability in an Aquaplanet General Circulation Model, J. Adv. Modeling.Earth. Sys, 2, 24 pp.
- Matsumoto, H., R. P. Dziak, D. K. Mellinger,M. Fowler, J. Haxel, A. Lau, C. Meinig, J Bumgardner, and W. M. Hannah, 2006: Autonomous Hydrophones at NOAA/OSU and a New Seafloor Sentry System for Real-time Detection of Acoustic Events,
Oceans’06 MTS/IEEE-Boston, Boston, MA, 18–21 September 2006, 4 pp.
Conference Presentations
2019 | E3SM All Hands Meeting | Grid Imprinting Issues in E3SM | oral | Westminster, CO |
2018 | Pan-GASS UMAP Conference | A Super-Parameterized Model for the Exascale Era: Results from the new SP-E3SM | oral | Lorne, Austrailia |
2017 | AGU Fall Meeting | Entrainment and Dilution in Tropical Deep Convection | oral | New Orleans, LA |
2016 | AMS Tropical | Entrainment and Dilution in Tropical Deep Convection | oral | San Juan, PR |
2014 | Research Intersections | Climate Model Data For Non-Climate Scientists | oral | Miami, FL |
2014 | AGU Fall Meeting | A Lagrangian View of Moisture-Convection Dynamics | oral & poster | San Francisco, CA |
2014 | AMS Tropical Conference | DYNAMO Hindcasts with SP-CAM | oral & poster | San Diego, CA |
2013 | Young Scientist Symposium on Atmospheric Research | The Moist Static Energy Budget in DYNAMO Hindcasts | oral | Fort Collins, CO |
2013 | AGU Fall Meeting | The MSE Budget in Hindcast Experiments During DYNAMO | poster | San Francisco, CA |
2012 | MJO Workshop | poster | Honolulu, HI | |
2012 | AGU Fall Meeting | Vertically Varying Cumulus Entrainment and Convectively Coupled Equatorial Waves in a GCM | poster | San Francisco, CA |
2012 | NOAA Climate Diagnostics and Prediction Workshop | poster | Fort Collins, CO | |
2012 | Young Scientist Symposium on Atmospheric Research | Height Variable Entrainment in a GCM | oral | Fort Collins, CO |
2011 | CMMAP Winter Team Meeting | oral | Berkeley, CA | |
2010 | AMS Tropical Conference | The Role of Moisture-Convection Feedbacks in Simulating the MJO | oral | Tucson, AZ |
Paper Discussions
- Benestad (2016): A Mental Picture of the Greenhouse Effect
- Benestad et al. (2015): Learning from mistakes in climate research
- Biasutti and Sobel (2009): Delayed Rainfall over the African Sahel in a Warmer Climate
- Boer (1993): Climate Change and the Regulation of the Surface Moisture and Energy Budgets
- Chikira (2014): How can Radiative Heating Influence Atmospheric Humidity?
- Convective Parameterization Reading list
- Cook (2015): Role of Inertial Instability in the West African Monsoon Jump
- de Roode et al. (2012): Parameterization of the Vertical Velocity Equation for Shallow Cumulus Clouds
- Diaz and Aiyyer (2013): Energy Dispersion in African Easterly Waves
- Dilution of Convection
- Judd et al. (2008): A Geometric Understanding of Model Error
- Lappen and Schumacher (2014): The Role of Tilted Heating in the MJO
- Manabe and Wetherald (1975): The Effects of 2xCO2 on the Climate of a GCM
- O’Gorman (2011): The Effective Static Stability Experienced by Eddies in a Moist Atmosphere
- Pendergrass and Hartmann (2014): The Atmospheric Energy Constraint on Global-Mean Precipitation
- Ramanathan (1981): Ocean-Atmosphere Interactions in the CO2 Climate Problem
- Raymond and Jiang (1990): Long-Lived Mesoscale Convective Systems
- Skinner and Diffenbaugh (2014): Projected Changes in African Easterly Wave Intensity and Track in Response to Greenhouse Forcing
- Thorncroft and Blackburn (1999): Maintenance of the African Easterly Jet
Computer Tips / Tricks
- CDO vs NCO
- CDO: Bulk Diagnosis of Model Output
- CDO: Calculating Flux Terms
- CDO: Extracting a variable across several files
- CESM: Apparent Errors from shr_sys_flush()
- Github vs. Bitbucket
- NCL: A Function for Calculating Effective Static Stability
- NCL: A substitute for pointers when dealing with arrays of different sizes
- NCL: Averaging in blocks (i.e. converting to longer time steps)
- NCL: Cropping the white space from a PNG file
- Screen Recordings in Mac OSX
Atmospheric Model Info
- A Toy Lagrangian Thermal Model
- CESM: A [more] Portable Climate Model for Single-Column Experiments
- CESM: Adding an Idealized Land Mass to an Aqua-Planet
- CESM: Apparent Errors from shr_sys_flush()
- CESM: Aqua-Planet Mode with Prescribed SST
- CESM: Aqua-Planet with a Slab Ocean Model (SOM)
- CESM: Building CESM 1.2 on Mac OSX
- CESM: Common Errors when Building CESM 1.2 (OSX)
- CESM: Porting issues on a Generic Linux Machine
- Convective Parameterization Reading list
- What is Super-Parameterization?
Notes
- The Perturbation Kinetic Energy Budget
- The Perturbation Available Potential Energy Budget
- The Budgets of Perturbation Vorticity and Enstrophy
PhD Dissertation
Tropical Deep Convection, Entrainment, and Dilution
during the DYNAMO Field Campaign
The bulk of my dissertation was about making the distinction between entrainment and dilution in convection. The word “entrainment” is often used to imply that it is synonymous with dilution. I set out to answer whether this was the case by devising a method for directly measuring dilution. Dilution varies a lot depending on what quantity is being diluted, and this can get very complicated when a quantity is not conserved for moist adiabatic processes. For example, buoyancy and total water will have very different dilution rates for the same rate of mass entrainment.
Masters Thesis
The Role of Moisture-Convection Feedbacks in
Simulating the Intraseasonal Oscillation
My master’s thesis analyzed the sensitivity of the NCAR Community Atmosphere Model (CAM) to varying strength of the Tokioka et al. (1988) minimum entrainment threshold which suppresses deep convection. Increasing this threshold enhances the tropical intraseasonal variability in the model and produces a more coherent MJO as well as a drier and colder mean climate in the model. The Gross Moist Stability (GMS; see Raymond et al. 2009) was also reduced which may be responsible for allowing the model to build up the large-scale moisture anomalies associated with the MJO. Further analysis showed that changes to the time mean GMS is not a reliable metric for diagnosing the model’s ability to simulate a realistic MJO. This is because further CAM simulations which used an alternative method to enhance the MJO did not exhibit this change to the mean GMS. It appears that looking at the intraseasonal fluctuations of GMS provides a better diagnostic for assessing a model’s ability to sustain MJO variability.
Undergraduate Research
Internal Rays of the Mandelbrot Set
My undergraduate thesis focused on mapping the internal structure of the Mandelbrot set (see image below) by projecting a unit disc and the associated internal rays onto the various cardiod and circular bulbs of the Mandelbrot set. The points within these bulbs are associated with a specific period of attracting cycle for a certain connected Julia set defined by some hyperbolic polynomial. I was able to find a relationship between the period of a given bulb and the period of an attached bulb based on the angle of the internal ray which projects onto the connection point. None of this is particularly useful, but it was an interesting project that I really enjoyed working on with my advisor Dave Brown.
SOSUS Hydrophone Data Acquisition System
for Geo-Acoustic Montioring
I did a few internships during my undergraduate days at the Hatfield Marine Science Center (HMSC) with Bob Dziak’s Geo-Acoustics group. The first summer I was there I developed software to record acoustic data from the SOSUS hydrophone array which is operating at the Whidbey Island naval base in Puget Sound.
QUEphone: An Autonomous “Quasi-Eulerian”
Geo-Acoustic Hydrophone
The second summer at HMSC I was able to work on another hydrophone project called the Quasi-Eulerian Hydrophone (QUEphone). The QUEphone is an ARGO float with a hydrophone. This device can control its own buoyancy so that it can move up and down in the water column, which allows near real-time monitoring of acoustic events. Most of the time the float sits on the ocean floor and listens for seismic events. If a significant event occurs the float can pop up to the surface and communicate to the land station via satellite. This has many applications including early tsunami warning, but also offers a cheap alternative to acoustic monitoring with a moored hydrophone array which requires a ship to retrieve the data. When the QUEphone is ascending/descending it gets pushed around by the ocean currents so it can’t be as accurate for locating the source of seismic events as a moored hydrophone array, which is why it’s called Quasi-Eulerian.