S
S
S
Alys Thomas1, J.T. Reager1,2,
Jay Famiglietti1,2,3, Matt Rodell4
1 Dept.
of Earth System Science,
2 UC Center for Hydrologic Modeling,
3 Dept. of Civil and Environmental Engineering,
University of California, Irvine
4 Hydrological Sciences Laboratory, NASA GSFC,
Greenbelt, MD.
2013 AGU Fall Meeting
S A quantitative framework for measuring the severity of
regional water storage deficits based on terrestrial water
storage observations from NASA’s Gravity Recovery and
Climate Experiment (GRACE) satellite mission.
2013 AGU Fall Meeting
of Drought Characterization
S provides decision makers with a measurement of abnormal weather
variability, so that protection from possible impacts may be
implemented.
S is complex and there are a wide range of meteorological or
hydrological indices or indicators that can be used.
S requires an accurate selection of drought identification methods,
able to describe in a synthetic and clear manner the evolution of
drought conditions in space and time.
2013 AGU Fall Meeting
S GRACE can contribute to regional drought
characterization by measuring water storage deficits in a
previously-identified, drought-stricken area.
S The duration and magnitude of the deficit can serve as
new metrics to help quantify hydrological drought
severity.
2013 AGU Fall Meeting
Terrestrial Water Storage Anomalies
S Observations of monthly
changes in Earth’s gravity
field caused by mass
redistribution, which, over
land and after removal of the
atmospheric contributions,
are attributed primarily to the
movement of water in various
surface and sub-surface
hydrologic reservoirs.
[Landerer and Swenson, 2012]
• UT, Austin CSR, RL05 TWSA
[ global, 1° grids ]
• Jan 2003 – July 2013
• Analysis for each grid cell:
• Remove the mean
• Apply a 3-month moving average
2013 AGU Fall Meeting
Study
Texas Region
Amazon
Southeastern U.S.
S Records of meteorological
drought for reference
S Large area to minimize
GRACE error
2013 AGU Fall Meeting
Drought
Two drought databases are referenced to identify specific meteorological drought events
S
Office of U.S. Foreign Disaster Assistance
(OFDA)/Centre
for
Research
on
the
Epidemiology
of
Disasters
(CRED)
International Emergency Events
[EM-DAT, 2013; U.S. Drought Monitor, 2013]
S
Maps based on measurements of climatic,
hydrologic and soil conditions as well as
reported impacts and observations from more
than 350 contributors around the country
2013 AGU Fall Meeting
An updated quantitative
…
the substantial
deviation from the
normal annual or
seasonal cycle that can
then be considered a
true deficit
Strong seasonality still
dominates the signal
2013 AGU Fall Meeting
Methodology (1): Monthly
S We compute a 127-month climatology (January 2003-July 2013) for the
GRACE TWSA time series in each study region.
S This climatology represents the characteristic
variability of
water storage and serves as a baseline for identifying the occurrence
and severity of water storage deficits.
S Allows us to:
S characterize unique events, different from the typical annual cycle
S account for regions that have little or strong seasonality
2013 AGU Fall Meeting
Methodology (2): Water Storage
S Water storage deficits:
S calculated as the negative residuals after subtracting
the GRACE monthly climatology from the TWSA
time series.
S This distinguishes between relatively dry (negative)
and wet (positive) conditions
2013 AGU Fall Meeting
Calculation of
Water Storage
Information
about
TWSA, km3
Monthly
Magnitude, M
Water that is “missing”
Peak Magnitude of each event
Water Storage Deficits, km3
Duration, D
2013 AGU Fall Meeting
of Deficit Events
month)
Instantaneous Severity
Instantaneous
Severity(km
(km3 3*/month)
Amazon
Texas Region
Southeastern U.S.
Monthly
Severity, S(t)
S(t) = M (t) ´ D(t)
(Average Magnitude) x (Months, since deficit start)
2013 AGU Fall Meeting
of this GRACE-based framework
1.
a framework that provides additional information about
how much water is missing from a region
{the effects of meteorological drought on the hydrological system}
2.
a clear identification of water storage deficits and
quantification of their severity with an observation that
integrates both surface and subsurface storage
3.
a consistent method for severity calculation that can be
applied globally
2013 AGU Fall Meeting
A.
B.
C.
D.
E.
Region
No. of
events
B.
≥ 3 months
Time span
of each
event
C.
Peak Magnitude
(P)
No. of
events
≥ 3 months
Time
Jan-03
span
to
of
Jun-03
each
event to
Nov-03
A.
Region
Amazon
Amazon
Amazon
7
Area:
6,140,600 km 2
7
Area:
6,140,600 km 2
Zambezi
1
1,340,600 km 2
Zambezi
Southern
Texas
Great
Plains
1,340,600 km 2
Area:
Southern
Great
Plains
778,770
km 2
Area:
Jul-04
Jan-03 to
Dec-04
Jun-03to
Dec-05
Nov-03 to
Feb-07
Jul-04to
Oct-07
Dec-04 to
Feb-10
Dec-05to
Feb-11
Feb-07 to
Aug-11
Oct-07to
Oct-11
Feb-10 to
Aug-12
Feb-11to
Jan-13
Aug-11 to
Oct-11to
Jan-03
Dec-07to
Aug-12
Jan-13
S Summary of Results
F.
G.
H.
Duration
(D)
Average water
storage deficit
Total Severity
(S)
D.3
km
E.
(months)
F. 3
km
G.
(km3 months)
Coincides with a
meteorological
drought?
H.
Peak Magnitude
-407 (M
(P)ar-03)
Duration
6
(D)
Average water
-277
storage
deficit
Total Severity
-1662
(S)
-442 km
(Apr-04)
(months)
9
km3
-283
3
(km-2547
months)
Coincides with a
N
meteorological
drought?
Y
-407 (Mar-03)
-512 (Jul-05)
6
13
-277
-279
-1662
-3627
N
Y
-442 (Apr-04)
-235 Apr-07)
9
9
-283
-129
-2547
-1161
Y
N
-512 (Jul-05)
-370 (May-10)
13
13
-279
-253
-3627
-3289
Y
Y
-235 Apr-07)
-23 (Oct-11)
9
3
-129
-19
-1161
-57
N
N
-370 (May-10)
-175 Nov-12)
13
6
-253
-109
-3289
-654
3
-23 (Oct-11)
3
-19
-57
-222 (Apr-05)
-175 Nov-12)
60
6
-88
-109
-5280
-654
1
Nov-05 to
Jan-03 to
Aug-06
Dec-07
-28 (Jan-06)
-222 (Apr-05)
10
60
-17
-88
-170
-5280
4
Nov-08 to
Apr-09to
Nov-05
Aug-06
Jun-09 to
-25 (Feb-09)
-28 (Jan-06)
6
10
-15
-17
-90
-170
-21 (Aug-09)
4
-11
-44
4
Sep-09
Nov-08 to
Oct-10
to JulApr-09
13
Jun-09 to
Sep-09to
Dec-05
-25 (Feb-09)
-68 (Jan-13)
6
34
-15
-43
-90
-1462
778,770 km 2
Southeastern
Southeastern
United
States
U.S.
3
Area:
Southeastern
United
733,760States
km 2
Mar-09
Oct-10
to Jul13
Oct-10 to
Mar-11to
Dec-05
Mar-09to
Jun-11
3
Area:
Mar-13
Oct-10 to
Mar-11
Y
N
±11.25
N
mm/69.12
km3
Y
N
(Amazon)
Y
Y
N
±14.55
Y
mm/11.33
km3
N
N
(Texas),
Y
-21 (Aug-09)
4
-11
-44
N
-66 (Nov-07)
-68 (Jan-13)
14
34
-42
-43
-588
-1462
Y
Y
-21 (Jan-11)
-66 (Nov-07)
3
14
-24
-42
-72
-588
-60 (Jun-12)
6
-15
-90
-21 (Jan-11)
3
-24
-72
±16.02
N
mm/11.75
km3
Y
N
(SE
USA)
N
2013 AGU Fall Meeting
for Water Resources
S The severity metric ( S ) is most associated with reports of
A.
B.
C.
D.
E.
F.
widespread,
catastrophic
meteorological
drought.
Region
A.
Region
Peak Magnitude
(P)
Duration
(D)
Average water
storage deficit
Total Severity
(S)
D.3
km
E.
(months)
F. 3
km
G.
(km3 months)
No. of
events
≥ 3 months
Time
Jan-03
span
to
of
Jun-03
each
event to
Nov-03
Peak Magnitude
-407 (Mar-03)
(P)
Duration
6
(D)
Average water
-277
storage
deficit
Total Severity
-1662
(S)
-442 km
(Apr-04)
(months)
9
km3
-283
3
(km-2547
months)
Coincides with a
N
meteorological
drought?
Y
-407 (Mar-03)
-512 (Jul-05)
6
13
-277
-279
-1662
-3627
N
Y
-442 (Apr-04)
-235 Apr-07)
9
9
-283
-129
-2547
-1161
Y
N
-512 (Jul-05)
-370 (May-10)
13
13
-279
-253
-3627
-3289
Y
Y
-235 Apr-07)
-23 (Oct-11)
9
3
-129
-19
-1161
-57
N
N
-370 (May-10)
-175 Nov-12)
13
6
-253
-109
-3289
-654
Y
N
-23 (Oct-11)
3
-19
-57
N
-222 (Apr-05)
-175 Nov-12)
60
6
-88
-109
-5280
-654
Y
N
-28 (Jan-06)
-222 (Apr-05)
10
60
-17
-88
-170
-5280
Area:
7
Area:
6,140,600 km 2
Zambezi
1
1,340,600 km
2
Zambezi
Southern
Great Plains
1,340,600 km2
Coincides with a
meteorological
drought?
H.
Time span
of each
event
C.
7
6,140,600 km 2
H.
No. of
events
B.
≥ 3 months
Amazon
Amazon
G.
1
Jul-04
Jan-03 to
Dec-04
Jun-03to
Dec-05
Nov-03 to
Feb-07
Jul-04to
Oct-07
Dec-04 to
Feb-10
Dec-05to
Feb-11
Feb-07 to
Aug-11
Oct-07to
Oct-11
Feb-10 to
Aug-12
Feb-11to
Jan-13
Aug-11 to
Oct-11to
Jan-03
Dec-07to
Aug-12
Jan-13
Nov-05 to
Jan-03 to
Aug-06
Dec-07
3
Y
Y
2013 AGU Fall Meeting
for Water Resources cont.
Texas Water Storage Deficits
SE USA Water Storage Deficits
S Possible to monitor the intra-seasonal persistence of total water
storage deficits and surpluses (even in the wet season).
S Understanding the time evolution of deficit helps us understand the
severity of individual events
S Understanding the spatial evolution of deficits
2013 AGU Fall Meeting
S
S
S
S
Questions?
References
S
EM-DAT: The OFDA/CRED International Disaster Database (2013), Universite catholique de Louvain, Brussels, Belgium,
http://www.emdat.be/, Accessed January 2013.
S
Landerer, F. W., and S. C. Swenson (2012), Accuracy of scaled GRACE terrestrial water storage estimates, Wat. Resour. Res., 48,
W04531, doi: 10.1029/2011WR011453.
S
Tapley, Byron D., S. Bettadpur, J. C. Ries, P. F. Thompson, and M. M. Watkins (2004), GRACE Measurements of Mass
Variability in the Earth System. Science, 305 (5683), 503, doi: 10.1126/science.1099192.
S
U.S. Drought Monitor (2013), University of Nebraska-Lincoln, National Drought Mitigation Center (NDMC), the U.S.
Department of Agriculture (USDA), and the National Oceanic and Atmospheric Administration (NOAA).
http://droughtmonitor.unl.edu/archive.html.
Presenter Contact Info: Alys Thomas, thomasac@uci.edu
2013 AGU Fall Meeting
2013 AGU Fall Meeting
Drought cont.
S Standardized Precipitation Index
2013 AGU Fall Meeting
2013 AGU Fall Meeting
2013 AGU Fall Meeting
Water Storage Deficits
3-month SPI