@article {707321,
	title = {Potential predictability of the Madden-Julian Oscillation in a superparameterized model},
	journal = {Geophysical Research Letters},
	volume = {50},
	number = {21},
	year = {2023},
	pages = {e2023GL105705},
	abstract = {The Madden-Julian Oscillation (MJO) is a promising target for improving sub-seasonal weather forecasts. Current forecast models struggle to simulate the MJO due to imperfect convective parameterizations and mean state biases, degrading their forecast skill. Previous studies have estimated a potential MJO predictability 5-15 days higher than current forecast skill, but these estimates also use models with parameterized convection. We perform a perfect-model predictability experiment using a superparameterized global model, in which the convective parameterization is replaced by a cloud resolving model. We add a second silent cloud resolving component to the control simulation that independently calculates convective-scale processes using the same large-scale forcings. The second set of convective states are used to initialize forecasts, representing uncertainty on the convective scale. We find a potential predictability of the MJO of 35-40 days in boreal winter using a single-member ensemble forecast.},
	url = {https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023GL105705},
	author = {Sarah Weidman and Kuang, Zhiming}
}
@article {691558,
	title = {A rotation procedure to improve seasonally varying Empirical Orthogonal Function bases for MJO indices},
	journal = {Geophysical Research Letters.},
	volume = {49},
	number = {15},
	year = {2022},
	abstract = {Various indices have been defined to characterize the phase and amplitude of the Madden-Julian oscillation (MJO). One widely used index is the Outgoing Longwave Radiation (OLR) based MJO index (OMI), which is calculated using the spatial pattern of 30-96-day eastward-filtered OLR. The EOFs used to calculate the OMI in observations are prone to degeneracy and exhibit oscillations on the order of 10-20 days, despite initial filtering of the OLR. We propose a simple modification to the OMI that involves aligning the EOFs between neighboring days while retaining the spatial pattern described by the EOFs. This rotation method is implemented as a postprocessing step of the current OMI calculation and cleanly removes the spurious oscillations and degeneracy issues seen in the standard method. A similar rotation procedure can be implemented in calculations of other MJO indices.},
	url = {https://onlinelibrary.wiley.com/share/author/RBUHWJ6KBXTTBYUHCZBE?target=10.1029/2022GL099998},
	author = {Sarah Weidman and Ned Kleiner and Kuang, Zhiming}
}
@software {691559,
	title = {Software for Empirical Orthogonal Function rotation procedure for MJO indices},
	year = {2022},
	url = {https://github.com/sweidy/eof_rotation},
	author = {Sarah Weidman}
}
@article {691557,
	title = {The Alaskan Summer 2019 Extreme Heat Event: The Role of Anthropogenic Forcing, and Projections of the Increasing Risk of Occurrence},
	journal = {Earth{\textquoteright}s Future},
	number = {9},
	year = {2021},
	abstract = {Extreme heat occurred over Alaska in June{\textendash}July 2019, posing risks to infrastructure, ecosystem, and human health. It is vital to improve our understanding of the causes of such events and the extent to which anthropogenic forcing may alter their likelihood and magnitude. Here, we use multiple large ensembles of climate models, comprising thousands of simulated years, to investigate these issues. Our results suggest that the presence of anthropogenic radiative forcing increased the likelihood of the 2019 extreme heat event by as much as 6\%. Further we show the rate of occurrence of such an extreme heat event is likely to substantially increase in the future with increasing levels of atmospheric greenhouse gases. While uncertainty in projected climate risk from model choice leads to a broad range of future extreme heat event probabilities, some models project that with rapidly increasing levels of greenhouse gases the likelihood of such events would exceed 75\% by 2090.},
	url = {https://doi.org/10.1029/2021EF002163},
	author = {Sarah Weidman and Thomas L. Delworth and Sarah B. Kapnick and William F. Cooke}
}
@mastersthesis {691556,
	title = {Understanding changes in precipitation with climate change over wet and dry land},
	year = {2021},
	type = {Undergraduate thesis},
	abstract = {Observed precipitation increased moderately in both wet and dry regions over the past 60 years, contradicting the wet-gets-wetter, dry-gets-drier (WWDD) mechanism. This study uses the perturbation atmospheric energy budget to understand the projected increase in precipitation over dry and wet land with climate change. Using global climate model output, the change in each term in the perturbation energy budget was calculated as a regional average over wet and dry tropical land. Increases in precipitation over wet and dry tropical land are primarily driven by increases in radiative loss, which are moderated by increases in sensible heat flux. Although the dry static energy flux divergence has a strong spatial pattern, cancellation between the horizontal and vertical advection terms, as well as cancellation between the dynamic and thermodynamic components of vertical advection, result in relatively small contributions from the dry static energy flux divergence towards the change in precipitation in the regional average. Only when wet and dry regions are allowed to change seasonally is WWDD given, suggesting that the movement of wet and dry regions is a significant factor in opposing the WWDD mechanism over land.},
	url = {https://hdl.handle.net/1721.1/138942},
	author = {Sarah Weidman}
}
