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Mechanisms for Interannual Mechanisms for Interannual Variations in Summer Streamflow Variations in Summer Streamflow from Headwater Catchments in from Headwater Catchments in
Western MexicoWestern Mexico
David J. Gochis, Nat’l Center for Atmos. Res.Luis Brito-Castillo, CIBNOR, Guaymas, Son. MX
Presented: NOAA Climate Diagnostics and Pred. Workshop, Oct. 27, 2005
AcknowledgementsAcknowledgements
• Balaji Rajagopalan and Katrina Grantz (CU-Boulder)
– Grantz, K., B. Rajagopalan, M. Clark, and E. Zagona, Spatio-Temporal Variability of the North American Monsoon (submitted), Journal of Climate, Special issue on the North American Monsoon, 2005.
• http://civil.colorado.edu/~balajir/ publications
• CNA
• NOAA-OGP GEWEX Americas Prediction Project: NA16GP2002
Objectives…Objectives…
• Provide a basic overview of the hydroclimatology of the headwater region in the Sierra Madre Occidental
• Characterize rainfall-runoff relationships governing streamflow on intra-seasonal to inter-annual timescales
• Explore interannual variability of streamflow associated with the North American Monsoon, and the relationship between cool season and warm season flows
Data:Data:
Timeseries of monthly streamflow• 15 headwater catchments• BANDAS dataset, courtesy CNA
NCEP/Climate Prediction Center
1x1 gridded daily precipitation• uniformly disagg. to 0.1 • monthly averaged across basins
Water Management Issues:Gila River
Gila River BasinArizona and New Mexico
Basic Hydroclimatology
The “Monsoon” Water YearThe “Monsoon” Water Year
• Monthly mean cycle dominated by warm season rainfall associated with the N. American Monsoon (NAM)
• Jul-Aug-Sep flow volume accounts for 50-85% of total annual flow
• Minor appearance of secondary max in Dec-Jan in response to synoptic transient systems
• Maximum recorded flows occur during monsoon, late fall or early winter
Previous Findings…Previous Findings…(Dettinger and Diaz, (Dettinger and Diaz, JHMJHM; Gochis et al., 2003, ; Gochis et al., 2003, JHMJHM; Grantz ; Grantz
et al., 2005 (submitted et al., 2005 (submitted J.ClimJ.Clim))
Latitudinal transition to a summer-dominated regime proceeding southward from Mogollon Rim.
Monthly Percent of Mean Annual Flow Volume
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
1 2 3 4 5 6 7 8 9 10 11 12
Month
% o
f Ann
ual F
low
Salt River near Chrysotile, AZ
Verde River, Camp Verde, AZ
Gila River near Clifton, AZ
San Pedro @ Charleston, AZ
Rio Sonoita, Sonora, MX
Rio Mayo, Sonora, MX
Rio Fuerte, Sinaloa, MX
Gila River near RedRock, NM
0
50
100
150
200
250
300
350
400
450
1 2 3 4 5 6 7 8 9 10 11 12
Month
Str
eam
flo
w (
cfs
)
Regionalization of Precipitation and Regionalization of Precipitation and Streamflow Streamflow (Gochis and Brito-Castillo, J. Hydrol. in press)(Gochis and Brito-Castillo, J. Hydrol. in press)
• VARIMAX rotated EOF analysis of seasonal (JAS) streamflow reveals three distinct regions of coherent streamflow variability:
•EOF1 – north•EOF2 – south•EOF3 – east
• Explain ~ 71% of the JAS variance
• Nearly identical EOF analysis of seasonal (JAS) precipitation reveals three very similar regions
• Explain ~ 86% of the JAS variance
Regionalized Rainfall-Runoff Analyses: Regionalized Rainfall-Runoff Analyses: Runoff Coefficient (Qr=Q/P)Runoff Coefficient (Qr=Q/P)
• Seasonal increase in Qr peaking in Oct• Reductions in precipitation in greater proportion than reduction in streamflow result in the marked increase in Oct values• Distinct sub-regional differences in this evolution
Jul Oct
Jul-Aug-Sep
Seasonal Evolution of Precipitation, Runoff and Runoff Coefficient
0
0.2
0.4
0.6
0.8
1
1.2
J un J ul Aug Sep Oct
Month
0
50
100
150
200
250
EOF1 Qr
EOF2 Qr
EOF3 Qr
EOF1 P
EOF2 P
EOF3 P
EOF1 Q
EOF2 Q
EOF3 Q
21%
34%
19%
• Relationship between JAS P and Q is non-linear and the runoff fraction (Qr=Q/P) exhibits substantial interannual variability
• Tendency for Qr to trend towards the 1:1 line (increase in value) with higher precipitation values
• This feature is most pronounced in EOF2(south) which receives the most rainfall
• Possible indication that in-basin abstractions are being met so that basins produce runoff with higher efficiency with greater seasonal precipitation
Precipitation-Runoff Precipitation-Runoff Processes: Runoff Processes: Runoff FractionFraction
JAS Regionalized Precip. vs Streamflow
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
0 100 200 300 400 500 600 700
JAS Streamflow (mm)
JA
S P
rec
ipit
ati
on
(m
m)
Q EOF1
Q EOF2
Q EOF3
1:1
Streamflow Diagnostics:Precipitation – Streamflow Relationship
Precipitation – streamflow relationship is non-linearHigh rainfall very little infiltration high streamflowDecaying influence of in-basin abstractions
JAS Regionalized Precip. vs Streamflow
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
0 100 200 300 400 500 600 700
JAS Precipitation (mm)
JA
S S
tre
am
flo
w (
mm
)
Q EOF1
Q EOF2
Q EOF3
1:1
Interannual Relationships
Timeseries of Jan-Apr Flows
y = 0.4562x - 876.62
y = 0.1486x - 268.35
y = 0.0914x - 170.390
50
100
150
200
250
300
1940 1950 1960 1970 1980 1990 2000 2010
Str
ea
mfl
ow
(m
m) EOF1
EOF2
EOF3
Linear (EOF2)
Linear (EOF1)
Linear (EOF3)
Timerseries of Jul-Aug-Sep Flows
y = 0.196x - 297.94
y = -1.0476x + 2258.2
y = -0.6322x + 1326.6
0
50
100
150
200
250
300
350
400
1940 1950 1960 1970 1980 1990 2000 2010
Streamflow (mm)
Zone 1 (North)
Zone 2 (South)
Zone 3 (East)
Linear (Zone 1 (North))
Linear (Zone 2 (South))
Linear (Zone 3 (East))
Linear Trend in Flow Volume
Jan-Apr Jul-Sep
Region (mm/yr) (mm/yr)
EOF1 0.149 0.196
EOF2 0.456 -1.048
EOF3 0.091 -0.632
Streamflow Diagnostics:Volume Analysis (summer)
San Francisco River at Clifton, AZJuly, Aug: decreasing trendSep, Oct: increasing trend
San Francisco River at Clifton, AZ JULY
y = -0.4539x + 976.79
0
50
100
150
200
250
300
1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Year
Str
eam
flo
w (
cfs)
San Francisco River at Clifton, AZ AUGUST
y = -0.695x + 1558.6
0
200
400
600
800
1000
1200
1400
1600
1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Year
Str
eam
flo
w (
cfs)
San Francisco River at Clifton, AZ SEPTEMBER
y = 0.1866x - 221.29
0
100
200
300
400
500
600
700
800
900
1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Year
Str
eam
flo
w (
cfs)
San Francisco River at Clifton, AZ OCTOBER
y = 3.8691x - 7403.9
0
500
1000
1500
2000
2500
3000
3500
4000
4500
1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Year
Str
eam
flo
w (
cfs)
Date of Center of Mass (DOY)
0
50
100
150
200
250
300
350
1930 1940 1950 1960 1970 1980 1990 2000 2010
Year
DO
Y
SEXT
RAMO
BATO
MAYO
CHIN
URIQ
HUMA
PIAX
PRES
BALU
ACAP
CHOI
BADI
TAMA
Date of Center of Mass (DOY)
0
50
100
150
200
250
300
350
1930 1940 1950 1960 1970 1980 1990 2000 2010
Year
DO
Y
EOF1
EOF2
EOF3
Annual Streamflow Annual Streamflow Center of VolumeCenter of Volume
(Procedure by Stewart et al., 2004)
All Basins
EOF Comp.
• No consistent long-term trend in CoV date though EOF2 has had more frequent early peaks since mid 1990s
• Marked increase in CoV date variability since 1976-1977 climate shift most evident in individual basins
• Effect is to increase the occurrence of early season peaks prior to DOY 200 (7/19)
• Only EOF 1 (North) exhibits a weakly sig. correl. w/ ENSO
• Shift due possibly to shift in onset, decreased summer flows or increased cool season flows
Correlation Scores Between SOI and EOF Zone Averaged Runoff
-0.50
-0.40
-0.30
-0.20
-0.10
0.00
0.10
0.20
0.30
0.40
0.50
SOI (Oct-Mar) SOI (Jan-Jun) SOI (Apr-Sep) SOI (Jun-Sep)
Lag
Co
rrel
atio
n
Zone 1
Zone 2
Zone 3
Jul-Aug-Sep
n SOI (Oct-Mar) SOI (Jan-Jun) SOI (Apr-Sep) SOI (Jun-Sep)
39 Zone 1 -0.06 0.05 0.18 0.20
55 Zone 2 -0.18 0.03 0.40 0.42
33 Zone 3 -0.04 0.09 0.15 0.15
JAS Total Q JAS Total Q Correlation to ENSO: Correlation to ENSO: SOISOI
• Clear evolution towards stronger correlations at ‘decreasing’ lags
• Peak correlation occurs with EOF2 and concurrent SOI (sig. @ 95% level)
• Sign of correl. indicates that higher flows occur during La Nina (high SOI) and low flows occur during El Nino (low SOI)
SS
S – Significant @ 95%
JAS Total Q Correlation JAS Total Q Correlation to ENSO: TNI & Nino to ENSO: TNI & Nino 3.43.4
• Character of correlation is markedly different with respect to regions
• EOFs 1(North) and 3(East) exhibit modest negative correlations with TNI and N3.4 at all nearly all
• EOF2(South) exhibits no long term correl. with TNI or N3.4
TNI – ‘Trans-Nino Index’ of Trenberth and Stepaniak, 2001, J. Clim
Correlation Scores Between TNI and EOF Zone Averaged Runoff
-0.50
-0.40
-0.30
-0.20
-0.10
0.00
0.10
0.20
0.30
0.40
0.50
TNI (Oct-Mar) TNI (Jan-Jun) TNI (Apr-Sep) TNI (Jun-Sep)
Lag
Co
rre
lati
on
Zone 1
Zone 2
Zone 3
S SSS
SS
S
Correlation Scores Between Nino3.4 and EOF Zone Averaged Runoff
-0.50
-0.40
-0.30
-0.20
-0.10
0.00
0.10
0.20
0.30
0.40
0.50
Nino 3.4 (Oct-Mar) Nino 3.4 (Jan-Jun)
Nino 3.4 (Apr-Sep)
Nino 3.4(Jun-Sep)
Lag
Co
rre
lati
on
Zone 1
Zone 2
Zone 3
S SS S
SS S
1. S
an P
edro
del C
onchos
2. C
hin
ipas
3. M
ayo
4. U
rique
5. B
ato
pila
s
6. C
hoix
7. S
extin
8. H
um
aya
9. B
adiraguato
10. T
am
azula
11. R
am
os
12. P
iaxtla
13. P
resid
io
14. B
alu
art
e
15. A
caponeta
All Years
La Nina (Hi SOI)
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
Fraction of Annual Average
Basins
Composite
Composite JJAS Average Fraction of Total Annual Streamflow - SOI Based
All Years
El Nino (Lo SOI)
La Nina (Hi SOI)
Influence of ENSO on NAM Influence of ENSO on NAM Water ResourcesWater Resources
• Using composite El Niño/La Niña years from SOI:
• Spatially, it is seen that La Niña’s influence is enhanced in EOF2(south)
• Reason for large influence of La Niña is combined factor of more summer precip. and reduced winter precip. especially in southern basins during La Niñayears:
Effect of ENSO on Annual Flow Partitioning - JJAS Season Flows
0
200000
400000
600000
800000
1000000
1200000
1400000
1600000
1800000
Basins
Tota
l Str
eam
flow
Vol
ume
All Year JJAS
El Nino JJAS
La Nina JJAS
El Niño: Pct Change in JJAS Flow La Niña: Pct Change in JJAS Flow
EOF1 decreases During El Nino
Large sensitivityin EOF2
• Compositing EOF Qr values by strongest correlate (SOI-EOF2, TNI-EOF1 and 3) it is shown that higher JAS runoff fractions tend to occur with La Nina than with El Nino
• Difference in composite means significant @ 90% level in EOFs 1 and 2
• ENSO composite averages bound the all year averages
Interannual Variability Interannual Variability of the Runoff Fraction of the Runoff Fraction (Qr):(Qr):
Qr EOF1(TNI)
Qr EOF2(SOI)
Qr EOF3(TNI)
All Years
El Nino
La Nina0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
JAS Runoff Fraction for EOF Regions Separated by ENSO Phase
All Years
El Nino
La Nina
JJAS Composite JJAS Composite Difference MapsDifference MapsNCEP/NCAR Rean.:NCEP/NCAR Rean.:
• Subtracting SOI-based El-Nino from La-Nina years yields:
• Enhanced Pacific-North American continent SLP gradient
• Weaker E. Pac. Trade winds south of Mexico occur during La Nina compared to El Nino along with increased meridional component…
• Increased meridional winds into Mexico during La Nina present up to mid-levels (though more confined to the coast)
Flux into Mx. increased
Flux out of Mx. decreased
• Modestly enhanced PW field over entire NAM region (except E. Chih) w/ enhanced differences in southern region
JJAS Composite JJAS Composite Difference MapsDifference MapsNCEP/NCAR Rean.:NCEP/NCAR Rean.:
JAS Total Q ENSO JAS Total Q ENSO Correlation Modulated Correlation Modulated by PDO:by PDO:
• Brito-Castillo et al showed that correlations between ENSO and streamflow are significantly modulated by PDO (~ 76-77 shift)
• Correls. between concurrent SOI and Q increase in EOFs 2 and 3 during low PDO phase (79-99) compared to full record and compared to PDO high phase (45-76)
• Correl. between concurrent TNI and Q are significantly negative in EOFs 1(North) and 2(south) in high PDO phase (45-76)
• Low PDO phase exhibits weaker correl in EOF1, no correl in EOF2 but stronger correl in EOF3(East)
Correlation Scores Between SOI and EOF Zone Averaged Runoff for High and Low PDO Phases
-0.50
-0.40
-0.30
-0.20
-0.10
0.00
0.10
0.20
0.30
0.40
0.50
SOI-PDO High (1945-1976:Jun-Sep) SOI-PDO Low (1976-1999:Jun-Sep)
Lag
Co
rre
lati
on
Zone 1
Zone 2
Zone 3
Correlation Scores Between TNI and EOF Zone Averaged Runoff for High and Low PDO Phases
-0.60
-0.50
-0.40
-0.30
-0.20
-0.10
0.00
0.10
0.20
0.30
0.40
0.50
TNI-PDO High (1945-1976:Jun-Sep) TNI-PDO Low (1976-1999:Jun-Sep)
Lag
Co
rre
lati
on
Zone 1
Zone 2
Zone 3
S
S
S
SS
S
S
ConclusionsConclusions
• The North American Monsoon System exerts significant influence on regional streamflow both in the U.S. and in Mexico with effects being much more pronounced in Mexico
• Headwater systems in the Sierra Madre obtain, on average 50-85% of their annual flow from July-Oct in response to monsoon rains, compare to ~25% for Gila R.
• 3 coherent regions capture a significant majority of the spatial coherence in seasonal precipitation and streamflow (North, South and East)
• Monthly and seasonal rainfall runoff correlations and runoff fraction exhibit sub-regional behavior that is reasonably well encapsulated by the EOF composites; southern basins appear to achieve a ‘conditioned state’
ConclusionsConclusions• SOI impact on EOF2 (south) streamflow seems quite clear
• Significant positive correl.• La Nina (+ SOI) occurs with increased JJAS flow while El Nino (- SOI) occurs with decreased
JJAS flow• Reduced cool season flows also occur during La Nina results in JJAS having possessing large
fraction of annual flow• Mechanisms for increased streamflow seems to be that SOI favors the northward transport of
tropical moisture into southern MX resulting in higher PW values
• Impact of SOI on northern regions is not as well resolved • ENSO as defined by TNI or Nino3.4 indices exhibits neg. correl. with
EOF1 streamflow (and less so with EOF3, perhaps Atlantic influenced?)• Relationship mostly expressed through reduced JJAS flow during El Nino events and NOT as
substantial increase of JJAS flow during La Nina as with SOI• Broadly consistent with findings of Grantz and Rajagopalan
• PDO effects:• SOI:Q correlation in EOF2 increases during low PDO phase (1977-1999) compared full record
while TNI:Q correlation in EOF1 is greater during high PDO phase (1945-1976).• Nearly all basins exhibit higher JJAS fractions of total annual flow prior to 1977 than after 1977
though differences are on the order of 5-10%.• Change in JAS fraction of annual flow is explained by all basins exhibiting greater than or equal
cool season flows post 1977 compared to pre 1977. Increase in cool season flows result in shift in ‘center of volume’ of annual streamflow since 1977.
• Changes in JJAS flows across 1976-77 climate shift are regional dependent with EOF1 possessing increases in JJAS flow post 1977, EOF2 flows generally decreasing since 1977 and EOF3 flows showing mixed signals
NAME research is funded bythe NOAA-OGP with contributions from NSF, NASA and the Mexican Government
Publications:
–Gochis, D.J., L. Brito-Castillo, W.J. Shuttleworth, 2005: Hydroclimatology of the North American Monsoon region in northwest Mexico. J. Hydrol, In press.
–Grantz, K., B. Rajagopalan, M. Clark, and E. Zagona, Spatio-Temporal Variability of the North American Monsoon (submitted), Journal of Climate, Special issue on the North American Monsoon, 2005.
PDO Effect on JJAS StreamflowPDO Effect on JJAS Streamflow
JJAS Average Streamflow Pre- & Post-1977
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
SPDCSEXT
RAMO
BATO
MAYO
CHINURIQ
HUMA
PIAX
PRESBALU
ACAPCHO
I
BADI
TAMA
Basins
Str
ea
mfl
ow
(m
m)
Pre 1977
Post 1977
East North South Low Elev.
JAS Standardized Streamflow Anomalies - High - Low
East Northwest South Low Elev.
(Graphical Assist. by Todd Lane - NCAR)
1976-77 Climate Shift
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