Using Standardized Precipitation Index for Monitoring

1st Joint DMCSEE-JRC
Workshop On Drought Monitoring
21.-25. September 2009
Ljubljana, Slovenia
Using Standardized Precipitation Index for
Monitoring and Analyzing Drought
presented by Ertan TURGU*
[email protected]
Research Department
*Turkish State Meteorological Service, Ankara, Turkey
1st Joint DMCSEE-JRC Workshop On Drought Monitoring 21.-25. September 2009 Ljubljana, Slovenia
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TSMS
Drought Assessment Tools
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Percent of Normal
Rainfall Deciles
Palmer Drought Severity Index (PDSI)
Crop Moisture Index (CMI)
Surface Water Supply Index (SWSI)
Standardized Precipitation Index (SPI)
NDVI based indices
U.S. Drought Monitor
Key Indicators for Drought Monitoring
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Climate data(Precipitation,Temperature)
Soil moisture
Snowpack
Vegetation stress,
Stream flow levels
Ground water levels
Reservoir and lake levels
Short, medium and long-range forecasts
1st Joint DMCSEE-JRC Workshop On Drought Monitoring 21.-25. September 2009 Ljubljana, Slovenia
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Standardized Precipitation Index(SPI)
Strengths
• minimal data requirements (only monthly
precipitation data)
• simple and quick
• can help assess drought severity
• can answer such questions as; when, how
long, and how severe a drought is.
• can be computed for different time scales
• can be used for comparison between
locations
While Palmer's indices are water
balance indices that consider water supply
(precipitation), demand(evapotranspiration)
and loss (runoff), the Standardized
Precipitation Index (SPI) is a probability
index which is negative for drought, and
positive for wet conditions. As the dry or
wet conditions become more severe, the
index becomes more negative or positive.
Weaknesses
• Requires transformation to normal
distribution
• Requires long rainfall record (>30 years)
• Ignores water demand and other losses
1st Joint DMCSEE-JRC Workshop On Drought Monitoring 21.-25. September 2009 Ljubljana, Slovenia
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SPI software and SPI Classification:
•Intensity (severity)
•Frequency
•Duration (onset - end)
•Spatial Extent (area affected by)
Charts of SPI Values at 3 and 6 months Time Scales:
1st Joint DMCSEE-JRC Workshop On Drought Monitoring 21.-25. September 2009 Ljubljana, Slovenia
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Chart of Equiprobability Transformation from Fitted Gamma to Standard Normal
Distributions
we can determine minimum amount of rainfall that is required to avoid from a
drought formation at different severity categories and varying time scales.
1st Joint DMCSEE-JRC Workshop On Drought Monitoring 21.-25. September 2009 Ljubljana, Slovenia
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DROUGHT OCCURENCES AND SPATIAL ANALYSIS:
28°
32°
36 °
4 0°
4 4°
BULGARIA
KIR KLA RE LI
GR
EEC
E
E DÝRN E
KAS TAMON U
G IR ESU N
KAR S
CA NK IR I
A MAS YA
C O RU M
ARMENIA
G U MU SH AN E
BAY BU RT
TO KA T
BI LE CI K
I GD I R
ANKARA
ER ZUR U M
KIR IK KA LE
ESK IS EH IR
B ALIK ESI R
AR DA HA N
RI ZE
TRA BZO N
O RD U
B O LU
Y ALO VA
BU RS A
Ç AN A KKA LE
AR TVIN
SA MSU N
K AR AB UK
ÝSTANBUL
ÝZMÝT A DA PAZ AR I
40 °
GEORGIA
SEA
B AR TIN
ZON GU LD AK
TEK IR DA G
YOZG AT
40 °
A G RI
ER ZIN C AN
S IV AS
KU TAH YA
KI R SEH IR
MA NI SA
TU NC EL I
B IN GO L
A FYO N
U SA K
NE VS EH IR
ÝZ MÝR
BU RD U R
V AN
EL AZI G
BI TL IS
MAL ATY A
A YD IN
DE NI ZL I
IRAN
M US
K AYS ER I
A KSA R AY
N IGD E
K ONY A
DI YAR BA KI R
S IIR T
B ATMA N
A DI YA MAN
IS PAR TA
H AKK AR I
S IR NA K
K AH RA MAN MA RA S
MU G L A
MAR DI N
K AR AMA N
OSM AN IYE
AN TAL YA
ME RS IN
SA NL I UR FA
G AZI AN TEP
IRAQ
AD AN A
K IL IS
A NTA KYA
36 °
36°
3 - MONTH MODERATE DROUGHT
OCCURRENCES (%)
MEDITERRANEAN SEA
5
km
28 °
32°
28 °
7
36 °
32°
9
11
13
40 °
36°
44 °
4 0°
DMÝ
250
200
100
0
15 0
SYRIA
50
▲ SPI index has been applied
to long-term precipitation data at
101 stations for 1951-2001
period.
▲ Here, our aim is to identify
some areas vulnerable to
drought at comparable time
steps based on their occurence
frequencies.
S IN O P
BLACK
44°
BULGARIA
KIR KL A RE LI
S IN O P
BLACK
E DÝRN E
B AR TIN
GR
EE
CE
ZO N GU L D AK
TEK IR DA G
KAS TAMO N U
O R DU
TRA BZO N
KA RS
CA NK IR I
A MAS YA
C O RU M
ARMENIA
GU MU SH AN E
BAY BU RT
TO KA T
BI LE CI K
I GD I R
ANKARA
ER ZUR U M
KIR IK KA LE
ES KIS EH IR
B AL IK ESI R
AR DA HA N
RI ZE
G IR ESU N
B OL U
Y AL OVA
BU RS A
ÇA NA KKA LE
AR TVIN
SA MSU N
K AR AB UK
ÝSTANBUL
ÝZMÝT A DA PAZ AR I
40°
GEORGIA
SEA
YOZG AT
40 °
A GRI
ER ZIN C AN
S IV AS
KU TAH YA
K IR SEH IR
MA NI SA
U S AK
TU NC EL I
B IN GO L
A FYO N
NE VS EH IR
ÝZMÝR
DE NI ZL I
BU RD U R
BI TL IS
MAL ATY A
N IGD E
KO N YA
VA N
EL AZI G
A KS AR AY
AYD IN
IRAN
M US
K AYS ER I
DI YAR BA KI R
S IIR T
B ATMA N
A DI YA MAN
IS PAR TA
S IR NA K
H AKK AR I
K AH RA MAN MA RA S
MU GL A
MAR DI N
K AR AMA N
OSM AN IYE
AN TALYA
ME RS IN
G AZ IAN TEP
SA NL I UR FA
IRAQ
AD AN A
K IL IS
A NTA KYA
36°
36°
6 - MONTH MODERATE DROUGHT
OCCURRENCES (%)
MEDITERRANEAN SEA
28°
5
32°
36 °
7
9
11
40 °
1st Joint DMCSEE-JRC Workshop On Drought Monitoring 21.-25. September 2009 Ljubljana, Slovenia
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44°
DMÝ
25 0
2 00
15 0
1 00
0
50
SYRIA
km
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1.
2.
3.
CONCLUSION
In this study, frequency and severity of
meteorological droughts in Turkey have been
investigated from a hazard concept and a detailed
analysis of geographical variations in terms of the
drought vulnerability using the Standardized
Precipitation Index (SPI) is presented. Frequency of
drought events at different severity categories and
critical (threshold) rainfall data are computed at
different time scales to identify drought
vulnerability.
Monitoring drought requires multiple indicators or
indices.
New approahes such as numerical hydrological
models and numerical weather prediction models can
be used for monitoring drought together with
drought indexes.
1st Joint DMCSEE-JRC Workshop On Drought Monitoring 21.-25. September 2009 Ljubljana, Slovenia
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TSMS
Thank you for your attention…
[email protected]
1st Joint DMCSEE-JRC Workshop On Drought Monitoring 21.-25. September 2009 Ljubljana, Slovenia
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