Journal
JOURNAL OF CLIMATE
Volume 33, Issue 7, Pages 2485-2508Publisher
AMER METEOROLOGICAL SOC
DOI: 10.1175/JCLI-D-19-0439.1
Keywords
Atmosphere; North America; Atmospheric circulation; Drought; Pattern detection
Categories
Funding
- California Department of Water Resources [82-19834]
- NASA National Climate Assessment support [80NM0018F0563]
- Institute of the Environment and Sustainability at the University of California, Los Angeles
- Center for Climate and Weather Extremes at the National Center for Atmospheric Research
- Nature Conservancy of California
Ask authors/readers for more resources
Persistent winter ridging events are a consistent feature of meteorological drought across the western and southwestern United States. In this study, a ridge detection algorithm is developed and applied on daily geopotential height anomalies to track and quantify the diversity of individual ridge characteristics (e.g., position, frequency, magnitude, extent, and persistence). Three dominant ridge types are shown to play important, but differing, roles for influencing the location of landfalling atmospheric rivers (ARs), precipitation, and subsequently meteorological drought. For California, a combination of these ridge types is important for influencing precipitation deficits on daily through seasonal time scales, indicating the various pathways by which ridging can induce drought. Furthermore, both the frequency of ridge types and reduced AR activity are necessary features for explaining drought variability on seasonal time scales across the western and southwestern regions. The three ridge types are found to be associated in different ways with various remote drivers and modes of variability, highlighting possible sources of subseasonal-to-seasonal (S2S) predictability. A comparison between ridge types shows that anomalously large and persistent ridging events relate to different Rossby wave trains across the Pacific with different preferential upstream locations of tropical heating. For the South-ridge type, centered over the Southwest, a positive trend is found in both the frequency and persistence of these events across recent decades, likely contributing to observed regional drying. These results illustrate the utility of feature tracking for characterizing a wider range of ridging features that collectively influence precipitation deficits and drought.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available