Summary
This archive contains fine spatial resolution
translations of climate projections over the
contiguous United States (U.S.) developed using
three downscaling techniques (monthly BCSD Figure 1,
daily BCCA Figure 2, and daily LOCA Figure 3), CMIP3
hydrologic projections over the western U.S., and
two sets of CMIP5 hydrology projections,
corresponding to monthly BCSD climate projections,
and corresponding to daily LOCA climate projections,
both over the contiguous U.S. as well as Canadian
portions of the Columbia River and Missouri River
Basins.
Archive content is based on global climate
projections from the World Climate Research
Programme's (WCRP's) Coupled Model
Intercomparison Project phase 3 (CMIP3) multi-model dataset
referenced in the Intergovernmental Panel on Climate
Change Fourth Assessment Report, and the phase 5 (CMIP5) multi-model dataset
that informed the IPCC Fifth Assessment.
For information about downscaled climate and
hydrology projections development, please see the About
page.
Purpose
The archive is meant to provide access to climate
and hydrologic projections at spatial and temporal
scales relevant to some of the watershed and
basin-scale decisions facing water and natural
resource managers and planners dealing with climate
change. Such access permits several types of
analyses, including:
- assessment of potential climate change
impacts on natural and social systems (e.g.,
watershed hydrology, ecosystems, water and
energy demands).
- assessment of local to regional climate
projection uncertainty.
- risk-based exploration of planning and
policy responses framed by potential climate
changes exemplified by these projections.
Archive History
- November 2007: Archive launched, initially
serving 112 projections of monthly BCSD CMIP3
temperature and precipitation projections over
the contiguous U.S. for the period 1950-2099.
- December 2010: Archive expanded to include
(1) gridded meteorological observations that
guided BCSD CMIP3 application and (2) the
intermediate datasets developed during BCSD
application, namely the 2-degree "regrid" global
climate projections (i.e. over spatially
interpolated global climate model results from
native model resolution to a common 2-degree
grid over the contiguous U.S.) and 2-degree
bias-corrected versions of the regrid
projections.
- August 2011: Archive expanded to include
(1) 53 projections of daily BCCA CMIP3
projections of minimum temperature, maximum
temperature and precipitation for three periods
(1961-2000, 2046-2065, 2081-2100), with results
being of potential interest to ecological
studies requiring information on projected
diurnal temperature range and/or flood-related
studies requiring information about projected
daily precipitation patterns; and, (2) 112
projections of monthly and daily hydrologic
projections in the western U.S. associated with
the monthly BCSD CMIP3 projections.
- May 2013: Archive expanded to include (1)
234 projections of monthly BCSD CMIP5
projections of precipitation and monthly means
of daily-average, daily maximum and daily
minimum temperature; and, (2) 134 projections of
daily BCCA CMIP5 projections of precipitation
and daily maximum and daily minimum temperature,
all covering the period 1950-2099.
- July 2014: Archive expanded to include 97
projections of monthly and daily hydrologic
projections over the contiguous U.S. associated
with monthly BCSD CMIP5 projections.
- September 2016: Archive expanded to include
64 projections of daily LOCA CMIP5 climate
projections over the contiguous U.S. of
precipitation and daily maximum and daily
minimum temperature, all covering the period
1950-2099.
- June 2020: Archive expanded to include 64
projections of daily LOCA CMIP5 hydrology
projections over the contiguous U.S. as well as
Canadian portions of the Columbia River and
Missouri River Basins, daily maximum and daily
minimum temperature, all covering the period
1950-2099.
Through September 2022, this website has served
projections to over 5,400 users, collectively issued
through over 100,000 requests. Geographically, the
requests have covered the contiguous U.S. and parts
of southern Canada and northern Mexico.
Terms of Use
These projections are being distributed to
interested users for consideration in research and
planning applications. Such applications may include
any project carried out by an individual or
organized by a university, a scientific institute,
public agency, or private sector entity for research
or planning purposes. Any decision to use these
projections is at the interested user's discretion
and subject to the Disclaimer provided below.
Disclaimer
These projections are being made available to
provide immediate access for the convenience of
interested persons. They are being made available by
Archive Collaborators (i.e. Bureau
of Reclamation, California-Nevada Climate
Applications Program, Climate Analytics Group, Cooperative Institute for
Research in Environmental Sciences, Lawrence
Livermore National Laboratory, National
Center for Atmospheric Research, Santa
Clara University, Scripps
Institution of Oceanography, Southwest Climate Adaptation
Science Center, U.S. Army Corps of Engineers,
and U.S.
Geological Survey). Archive Collaborators
believe the information to be correct
representations of potential high-resolution
climate/hydrologic variations and changes subject to
the limitations of the CMIP3 and CMIP5 global
climate simulations, and the downscaling methods and
their limitations, as described elsewhere in this
web site. However, human and mechanical errors
remain possibilities. Therefore, Archive
Collaborators do not guarantee the accuracy,
completeness, timeliness, or correct sequencing of
the information. Also, neither Archive
Collaborators, nor any of the sources of the
information shall be responsible for any errors or
omissions, or for the use or results obtained from
the use of this information.
Acknowledgements and Citation of these
Projections
Whenever you publish research based on
projections from this archive, please include two
acknowledgements:
- First, acknowledge the superceding effort.
For CMIP3, the following is language
suggested by the CMIP3 archive hosts
at PCMDI: "We acknowledge the
modeling groups, the Program for
Climate Model Diagnosis and
Intercomparison (PCMDI) and the
WCRP's Working Group on Coupled
Modelling (WGCM) for their roles
in making available the WCRP
CMIP3 multi-model dataset.
Support of this dataset is
provided by the Office of
Science, U.S. Department of
Energy." PCMDI also requests
that in first making reference to
the projections from this archive,
please first reference the CMIP3
dataset by including the phrase "the
World Climate Research
Programme's (WCRP's) Coupled
Model Intercomparison Project
phase 3 (CMIP3) multi-model
dataset". Subsequent references
within the same publication might
refer to the CMIP3 data with terms
such as "CMIP3 data", "the
CMIP3 multi-model dataset", "the
CMIP3 archive", or the "CMIP3
dataset".
For CMIP5, , the model output should
be referred to as "the CMIP5
multi-model ensemble
[archive/output/results/of
simulations/dataset/ ...]". In
publications, you should include a
table (referred to below as Table
XX) listing the models and
institutions that provided model
output used in your study. In this
table and as appropriate in figure
legends, you should use the CMIP5
official model names found in "CMIP5
Modeling Groups and their Terms
of Use". In addition, an
acknowledgment similar to the
following should be included in your
publication:
"We acknowledge the World Climate
Research Programme's Working Group
on Coupled Modelling, which is
responsible for CMIP, and we thank
the climate modeling groups (listed
in Table XX of this paper) for
producing and making available their
model output. For CMIP the U.S.
Department of Energy's Program for
Climate Model Diagnosis and
Intercomparison provides
coordinating support and led
development of software
infrastructure in partnership with
the Global Organization for Earth
System Science Portals."
where, "Table XX" in your paper should
list the models and modeling groups that
provided the data you used. In addition
it may be appropriate to cite one or
more of the CMIP5 experiment design
articles listed on the CMIP5 reference
page.
- Second, generally acknowledge this archive
as "Downscaled CMIP3 and CMIP5 Climate and
Hydrology Projections" archive at
http://gdo-dcp.llnl.gov/downscaled_cmip_projections/.
To reference specific information in the
archive, you may also use the following
references:
- (for original reference to this
website) Maurer, E. P., L. Brekke, T.
Pruitt, and P. B. Duffy (2007),
'Fine-resolution climate projections
enhance regional climate change impact
studies', Eos Trans. AGU, 88(47),
504.
- (for reference to all BCSD and BCCA
downscaled content, including CMIP3 and
CMIP5), you can reference the technical memorandum
using the following citation:
Reclamation, 2013. 'Downscaled CMIP3 and
CMIP5 Climate and Hydrology Projections:
Release of Downscaled CMIP5 Climate
Projections, Comparison with preceding
Information, and Summary of User Needs',
prepared by the U.S. Department of the
Interior, Bureau of Reclamation,
Technical Services Center, Denver,
Colorado. 47pp.
- (for BCSD CMIP3 hydrologic
projections) Reclamation, 2011.
'West-Wide Climate Risk Assessments:
Bias-Corrected and Spatially Downscaled
Surface Water Projections', Technical
Memorandum No. 86-68210-2011-01,
prepared by the U.S. Department of the
Interior, Bureau of Reclamation,
Technical Services Center, Denver,
Colorado. 138pp.
- (for BCSD CMIP5 hydrologic
projections) you can reference the technical memorandum
using the following citation:
Reclamation, 2014. 'Downscaled CMIP3 and
CMIP5 Climate and Hydrology Projections:
Release of Hydrology Projections,
Comparison with preceding Information,
and Summary of User Needs', prepared by
the U.S. Department of the Interior,
Bureau of Reclamation, Technical
Services Center, Denver, Colorado. 110
pp.
- (for LOCA CMIP5 projections) you
can reference: Pierce, D. W., D. R.
Cayan, and B. L. Thrasher, Statistical
Downscaling Using Localized Constructed
Analogs (LOCA), Journal of
Hydrometeorology, 15(6), 2558-2585,
2014.; and Pierce, D. W., D. R. Cayan,
E. P. Maurer, J. T. Abatzoglou, and K.
C. Hegewisch, 2015: Improved bias
correction techniques for hydrological
simulations of climate change. J.
Hydrometeorology, v. 16, p. 2421-2442.
DOI:
http://dx.doi.org/10.1175/JHM-D-14-0236.1.
- (for LOCA CMIP5 hydrologic
projections) you can reference the technical memorandum
using the following citation: Vano, J.,
J. Hamman, E. Gutmann, A. Wood, N.
Mizukami, M. Clark, D. W. Pierce, D. R.
Cayan, C. Wobus, K. Nowak, and J.
Arnold. (June 2020). Comparing
Downscaled LOCA and BCSD CMIP5 Climate
and Hydrology Projections - Release of
Downscaled LOCA CMIP5 Hydrology. 96 p.
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Figure 1.
Central Tendency Changes in Mean-Annual
Precipitation over the contiguous U.S. from
1970-1999 to 2040-2069 for BCSD3, BCSD5, and
Difference.
Figure 2.
BCCA CMIP3 Daily Climate Analysis example -
Calendar-day, ensemble-mean change in
20-year diurnal temperature range for three
percentiles of diurnal range: 10th, 50th and
90th for the period pairs shown.
Figure 3. Comparison of the ensemble median
of max daily precipitation for three daily
downscaling methods. Shown is the difference
(first column) between the historical period
(1970-1999) and the future period
(2040-2069) for each method: BCCA (top),
BCSDm (middle) and LOCA (bottom). The second
column shows differences between future
changes of each method, each row represents
differences between pairs of methods:
LOCA-BCSDm (top), LOCA-BCCA (middle) and
BCSDm-BCCA (bottom).
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