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Drought monitoring and mitigationby FAO 5-
16 N
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ber,
2010
by FAOin selected regions of the world
Zoltan Balint - Chief Technical Advisor & Peris Muchiri – Meteorologist at
ion
Mee
ting,
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eva,
15
& Peris Muchiri – Meteorologist
FAO – Somalia Water and Land Information Management
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Consultation Meeting on the Proposed Integrated Drought Management ProgrammeGeneva, Switzerland, 15-16 November, 2010
What is drought?
Food shortage can be caused by•Arid conditions
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Interpretation of drought in the media, in relief work, etc. is often too wide: drought is anything that results in food h t •Floods
•Diseases•Human conflicts •Market problems •Unsatisfactory use of resources or•Real drought
Drought is: atio
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5shortage.
Food shortage = Drought?
Serious anomaly - Long duration
Drought is:
“an extended period during which fresh water availability (particularly rainfall and soil moisture) is below normal and temperatures (and or winds) are high…”
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Understand (phenomena, threat) Monitor Take mitigating
actions
To be able to manage drought we need to
Plan
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OBJECTIVE ASSESSMENTS
EVIDENCE BASED DECISIONS
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MONITORING SYSTEMS
PROPER METHODS & DATA
RELIABLE INFORMATION
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How to measure the severity of drought?Drought indexes
- Physical indexes (water balance)- Statistical indexes (time series analysis)
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•Single parameter (precipitation, NDVI) •Multiple parameter
Multiple parameter
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precipitation temperature soil moisture wind
Combined effect
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precipitation temperature soil moisture wind
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deficiency
Distributionand run-lengthin antecedent
period(s)
excess
Distributionand run-lengthin antecedent
period(s)
deficiency
Distributionand run-lengthin antecedent
period(s)
no data
No methodology
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Comparative analysis
Combined Drought Index (CDI)Includes the above 6 parameters
The Combined Drought Index (CDI) includes:
• Rainfall amounts and the run-length of the rainfall deficits 6
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deficits,
• NDVI and the run-length of the below average NDVI values,
• Temperature and the run-length of the above average temperatures on
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temperatures.
Note: Run-length is the number of dekads (or time units) continuously under or above the average.
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ACTUAL VALUE MULTI-YEAR AVERAGEcompared to
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Ratio Climatic conditions
1.0
Greater than 1.0 Better than normal
normal
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Smaller than 1.0 Worse than normal
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The CDI for dry years ranges between 0.0 and 1.0
Precipitation drought index
)(,
1
)(,
1 0),(
0)(,
,
1
*1 P
im
n
k
Pkm
n
k
IP
jkjm
IP
jjmi
mi R
Rn
Pn
PPDI
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Temperature drought index
Vegetation drought index
)(,
1
)(,
0)(,
1 0),(
,
1
*
1
Tim
n
k
Tkm
IP
jjmi
n
k
IP
jkjm
mi R
Rn
T
Tn
TDI
)(1
)(),
0)(,
1
* NDVI
n
k
NDVIkm
IP
jjmi
i
Rn
NDVIVDI on
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g g
Combined drought index
)(,
1 0),(
,1 NDVI
imn
k
IP
jkjm
mi RNDVI
n
VDI
mimimimi VDITDIPDICDI ,,2,, *25.0*25.0*5.0
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The above mathematical expressions in words can be written as below, where LTM stands for long-term mean or long-term average and summation (average) as well as run-length is calculated for the chosen interest period (e.g. 5 dekads, 3 months etc.)
Precipitation Drought Index =(actual rainfall sum / LTM rainfall sum) * Square root of (LTM of the longest rainfall deficit runs / actual longest rainfall deficit run)
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Vegetation Drought Index =(actual average NDVI / LTM average NDVI) * Square root of (LTM of the longest NDVI deficit runs / actual longest NDVI deficit run)
Temperature Drought Index = (LTM average temperature / actual average temperature) * Square root of (LTM of the longest excess temperature runs / actual longest excess temperature run)
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the longest excess temperature runs / actual longest excess temperature run)
It is important to note that the PDI, VDI and TDI are drought indexes by themselves. In case of missing time series they can be calculated on their own or in any combination with the available time series.
The CDI (the combination of the above three) basically answers the question:Where are we now compared to the multi-year average situation?
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Kenya - Dagoretti
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Kenya - Kakamega
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Somali stations
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Debrecen 1980 -2000
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Szeged 1951 -2000
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CONCLUSIONSDrought is a complex natural phenomenon with several socio-economic impacts
For monitoring drought, objectively measurable indexes are needed to measure as many contributing parameters as possible
Rainfall and soil moisture deficiency, excess temperature and wind as well as the run-length of the stress periods (continuous deficiency or excess of the above parameters) need to be included in the chosen drought monitoring index.
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The Combined Drought Index (CDI) meets the above requirements, although due to lack of data wind is not yet included
The CDI can calculate the Precipitation Drought Index, the Temperature Drought Index and the Vegetation Drought Index individually or in any combination of the three.
There is flexibility in choosing the Interest Period (No. of dekads or months,) depending on the purpose of the research
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sultaThe CDI gives good approximations even with data series less then 20 years long
and works well in data scarce environment
The results of the CDI time series can be the inputs into further statistical analysis
Initial socio-economic tests confirmed the drought periods calculated by the CDI. Further, scientific socio-economic analysis is under way. Based on the statistical and the socio-economic analysis a drought classification system (mild, medium, severe, extreme) can be developed.
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Drought Preparedness Planning and Mitigation by FAO in
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g ythe Near East Region
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recommends six steps that are fundamental in developing and implementing a national drought
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The Near-East Drought Preparedness Planning Manual
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Step 1: Creating Political Momentum and Authority Step 2: Strategic Planning and CoordinationStep 3: Fostering Involvement and Developing Common Understandings Step 4: Investigating Drought Monitoring Risk and
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Management Options Step 5: Writing a Drought Preparedness Plan Step 6: Implementing a Drought Preparedness Plan
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Conclusions and Recommendations of the Review Report
Gain a better understanding of the drought hazardFocus more attention on drought mitigation and preparedness planning
Moving from treating drought as an emergency to a new approach of long-term planning and implementing sustainable practices Strengthening governments’ drought mitigation and preparedness efforts
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5Strengthening governments’ drought mitigation and preparedness effortswith assistance from the United Nations and other organizations, Supporting and participating in regional networks and mechanisms
The creation of guidelines to assist countries in the preparation and implementation of national action programs for combating drought
Involving and mobilizing all communities
Establishment of drought early warning systems
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Creation of enabling mechanisms that would be entrusted with drought mitigation measures
Understand (phenomena, threat) Monitor Plan Take mitigating
actions
Acknowledgements:
Note:The Combined Drought Index was developed in 2009 in FAO-SWALIM by Zoltan Balint, Francis Mutua and Peris Muchiri
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Contacts:
1. Kenya Meteorological Department – for providing data
2. Michele Bernardi – FAO Rome – for providing advice
3. University of Nebraska, Lincoln – for contributing to the two above reports
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Zoltan Balint: [email protected] Mutua: [email protected] Muchiri: [email protected] Bazza: [email protected] Frenken: [email protected] Bernardi: [email protected]
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Thank you for your attention
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Somalia Water and Land Information Management System WM
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