skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Using Self-Organizing Maps to Identify Coherent CONUS Precipitation Regions

Abstract

Extreme precipitation events have major societal impacts. These events are rare and can have small spatial scale, making statistical analysis difficult; both factors are mitigated by combining events over a region. A methodology is presented to objectively define “coherent” regions wherein data points have matching annual cycles. Regions are found by training self-organizing maps (SOMs) on the annual cycle of precipitation for each grid point across the contiguous United States (CONUS). Using the annual cycle for our intended application minimizes problems caused by consecutive dry periods and localized extreme events. Multiple criteria are applied to identify useful numbers of regions for our future application. Criteria assess these properties for each region: having many more events than experienced by a single grid point, good connectedness and compactness, and robustness to changing the number of regions. Our methodology is applicable across datasets and is tested here on both reanalysis and gridded observational data. Precipitation regions obtained align with large-scale geographical features and are readily interpretable. Useful numbers of regions balance two conflicting preferences: larger regions contain more events and thereby have more robust statistics, but more compact regions allow weather patterns associated with extreme events to be aggregated with confidence. For 6-hmore » precipitation, 12–15 regions over the CONUS optimize our metrics. The regions obtained are compared against two existing region archetypes. For example, a popular set of regions, based on nine groups of states, has less coherent regions than defining the same number of regions with our SOM methodology.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]
  1. Univ. of California, Davis, CA (United States)
Publication Date:
Research Org.:
Univ. of California, Davis, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1595106
Grant/Contract Number:  
SC0016605
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Climate
Additional Journal Information:
Journal Volume: 32; Journal Issue: 22; Journal ID: ISSN 0894-8755
Publisher:
American Meteorological Society
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES; Atmosphere; Climatology; Precipitation; Neural Networks; North America

Citation Formats

Swenson, Leif M., and Grotjahn, Richard. Using Self-Organizing Maps to Identify Coherent CONUS Precipitation Regions. United States: N. p., 2019. Web. doi:10.1175/JCLI-D-19-0352.1.
Swenson, Leif M., & Grotjahn, Richard. Using Self-Organizing Maps to Identify Coherent CONUS Precipitation Regions. United States. doi:10.1175/JCLI-D-19-0352.1.
Swenson, Leif M., and Grotjahn, Richard. Thu . "Using Self-Organizing Maps to Identify Coherent CONUS Precipitation Regions". United States. doi:10.1175/JCLI-D-19-0352.1. https://www.osti.gov/servlets/purl/1595106.
@article{osti_1595106,
title = {Using Self-Organizing Maps to Identify Coherent CONUS Precipitation Regions},
author = {Swenson, Leif M. and Grotjahn, Richard},
abstractNote = {Extreme precipitation events have major societal impacts. These events are rare and can have small spatial scale, making statistical analysis difficult; both factors are mitigated by combining events over a region. A methodology is presented to objectively define “coherent” regions wherein data points have matching annual cycles. Regions are found by training self-organizing maps (SOMs) on the annual cycle of precipitation for each grid point across the contiguous United States (CONUS). Using the annual cycle for our intended application minimizes problems caused by consecutive dry periods and localized extreme events. Multiple criteria are applied to identify useful numbers of regions for our future application. Criteria assess these properties for each region: having many more events than experienced by a single grid point, good connectedness and compactness, and robustness to changing the number of regions. Our methodology is applicable across datasets and is tested here on both reanalysis and gridded observational data. Precipitation regions obtained align with large-scale geographical features and are readily interpretable. Useful numbers of regions balance two conflicting preferences: larger regions contain more events and thereby have more robust statistics, but more compact regions allow weather patterns associated with extreme events to be aggregated with confidence. For 6-h precipitation, 12–15 regions over the CONUS optimize our metrics. The regions obtained are compared against two existing region archetypes. For example, a popular set of regions, based on nine groups of states, has less coherent regions than defining the same number of regions with our SOM methodology.},
doi = {10.1175/JCLI-D-19-0352.1},
journal = {Journal of Climate},
number = 22,
volume = 32,
place = {United States},
year = {2019},
month = {10}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share: