Large-Scale Atmospheric Circulation over the Pacific Northwest
Large-scale atmospheric circulation refers to patterns of movement in the atmosphere on the scale of 1000s of kilometers. Different patterns are associated with and can be the driving force behind different weather conditions on the ground, like storms or heat waves. This work evaluates how well climate models can capture these patterns, and analyzes how these patterns may change over the Pacific Northwest in future global warming.
Publications:
Taylor, G., P. C. Loikith, H. K. Lee, B. Lintner, and C. M. Aragon, 2023: Projections of Large-Scale Atmospheric Circulation Patterns and Associated Temperature and Precipitation over the Pacific Northwest using CMIP6 Models, J. Climate, 36, 7257-7275, https://doi.org/10.1175/JCLI-D-23-0108.1
Taylor, G., P. C. Loikith, C. M. Aragon, D. E. Waliser, and H. Lee, 2023: CMIP6 Model Fidelity at Simulating Large-Scale Atmospheric Circulation Patterns and Associated Temperature and Precipitation over the Pacific Northwest. Clim. Dyn., 60, 2199-2218, https://doi.org/10.1007/s00382-022-06410-1.
Aragon, C. A., P. C. Loikith, N. McCullar, and A. Mandilag, 2020: Large Scale Meteorological Patterns Associated with Extreme Precipitation Events over Portland, OR. Int. J. Climatol., https://doi.org/10.1002/joc.6487. RMets Link
Presentations:
Projections of Large-Scale Atmospheric Circulation Patterns and Associated Temperature and Precipitation Anomalies over the Pacific Northwest using CMIP6 Models, Fall Meeting of the American Geophysical Union, New Orleans, LA, December 2021 (talk by Graham Taylor).
Evaluating CMIP6 Model Fidelity at Simulating Large-Scale Atmospheric Circulation Patterns and Associated Temperature and Precipitation over the Pacific Northwest, Fall Meeting of the American Geophysical Union, New Orleans, LA, December 2021 (poster by Paul Loikith).
Projections of Large-Scale Meteorological Patterns, Temperature, and Precipitation over the Pacific Northwest using CMIP6 Models, Virtual 11th Northwest Climate Conference, April, 2021 (talk by Graham Taylor).
Projections of Future Large-Scale Meteorological Patterns, Temperature, and Precipitation over the Pacific Northwest, Virtual Fall Meeting of the American Geophysical Union, December, 2020 (poster by Graham Taylor).
Assessing Climate Change Impacts on Precipitation Over Bull Run Watershed, Northwest Climate Conference, Portland, Oregon, October, 2019 (poster by Graham Taylor)
Evaluation of CMIP5 model fidelity at capturing wet season large-scale meteorological patterns over the Pacific Northwest using self-organizing maps, Northwest Climate Conference, Portland, Oregon, October, 2019 (talk by Christina Aragon)
The range of large-scale circulation patterns over the Pacific Northwest in winter (December-January-February). 500 hPa anomalies are shaded and height is contoured, with a bold contour at 5600m.
Patterns range from rain producing "troughs" (Node 1) to warm and dry "ridges" (Node 10-12), and everything in between.
This research tests how well climate models simulate these patterns and the associated meteorology (temperature and precipitation), and analyzes what models say about the future.
Temperature anomalies (difference from average in °C) associated with winter circulation patterns, as simulated by climate models.
Model patterns are compared to observed patterns and the differences in pattern shape and strength are quantified.
Accurate simulation of temperatures associated with circulation gives us more confidence in the future projections of climate models.
Precipitation anomalies (% of average) associated with each winter circulation pattern, as simulated by climate models.
The range of large-scale circulation patterns over the Pacific Northwest in summer (June-July-August). 500 hPa anomalies are shaded and height is contoured, with a bold contour at 5780m.
Patterns are not uniformly frequent. For example, Node 1 and Node 9 are relatively rare summer storm patterns (note the precipitation anomalies below), while Node 6 and 7 are very frequent average summer patterns.
Future changes in the frequency of rare summer rain patterns may be highly impactful.
Temperature anomalies (difference from average in °C) associated with summer circulation patterns, as simulated by climate models.
Precipitation anomalies (% of average) associated with each summer circulation pattern, as simulated by climate models.