Hydrological Drought Indices: Outcomes of Previous Workshops

Transcription

1 World Meteorological Organization Working together in weather, climate and water Hydrological Drought Indices: Outcomes of Previous Workshops Robert Stefanski Chief, Agricultural Meteorology Division WMO

2 Overview of WMO 2

3 World Meteorological Organization WMO OMM United Nations agency for weather, climate, hydrology and water resources and related environmental issues. 189 Members from National Meteorological and Hydrological Services (NMHS) 10 major scientific & technical programmes (Secretariat) 8 Technical Commissions advise & guide activities of programmes (Experts) 6 Regional Associations involved in implementation 3

4 Five priority Areas WMO OMM Global Framework for Climate Services; Aviation meteorological services; Capacity-building for the developing and least developed countries; Implementation of the WMO Integrated Global Observing System (WIGOS) and WMO Information System (WIS); Disaster risk reduction 4

5 WMO Technical Commissions WMO OMM Commission for Aeronautical Meteorology (CAeM) Commission for Agricultural Meteorology (CAgM) Commission for Atmospheric Sciences (CAS) Commission for Basic Systems (CBS) Commission for Climatology (CCl) Commission for Hydrology (CHy) Commission for Instruments and Methods of Observation (CIMO) Joint WMO-IOC Commission for Oceanography and Marine Meteorology (JCOMM) 5

6 Drought 6

7 The Cycle of Disaster Management Source: Wilhite - NDMC 7

8 Comparing drought to other natural WMO OMM hazards slow onset, creeping phenomenon, a nonevent difficult to determine drought onset and end absence of a precise, universal definition impacts are nonstructural and spread over large areas severity and impacts best defined by multiple indices and indicators Source: Wilhite - NDMC 8

9 Comparing drought to other natural WMO OMM hazards no consistent methodology for assessing impacts or a data base for archiving impacts impacts are complex, affect many people, and vary on spatial and temporal timescales, multiple and migrating epicenters mitigation interventions are less obvious water shortages increase conflict regulatory, legal authority (interstate and transboundary issues) makes monitoring, early warning, impact assessment, response, mitigation, and planning difficult! Source: Wilhite - NDMC 9

10 Drought is a normal part of climate in most WMO OMM climate regimes but differs in terms of Causal factors Multiple Regional in scale Forcing functions not well understood Impacts Institutional structure for monitoring, mitigation, response, and planning/policy Societal coping capacity (vulnerability/resilience) Government policies (e.g., data sharing across ministries, response measures) Government/donor response capability Source: Wilhite - NDMC 10

11 Is drought a departure from normal climate or a part of normal climate? 11

12 Drought is a normal part of climate! 12

13 Droughts differ in terms of: WMO OMM Spatial Extent 13

14 Natural and Social Dimensions of Drought WMO OMM Decreasing emphasis on the natural event (precipitation deficiencies) Increasing emphasis on water/natural resource management Increasing complexity of impacts and conflicts Meteorological Rainfall Deficiencies Heat Stress Agricultural Soils Crops Range Livestock Forests Hydrological Water Supply Snow Depth Recreation Tourism Hydropower Socio-economic Societal Impact Time/Duration of the event 14

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16 Components of a Drought Early Warning WMO OMM System Monitoring networks Who is the responsible authority? Multiple networks? Data retrieval systems Data quality control Data analysis converting data into information Interaction with end users/stakeholders Creating an end-to-end-to end system Information delivery timely, reliable 16

17 Key Indicators for Monitoring WMO OMM Drought climate data (precipitation, temperature) soil moisture stream flow ground water reservoir and lake levels snow pack short, medium, and long range forecasts vegetation health/stress and fire danger sectoral impacts 17

18 Drought impacts Droughts have different physical characteristics Society is dynamic so each drought event is superimposed onto society impacts reflect changing vulnerabilities Does your country have a monitoring system for recording drought impacts? How do you incorporate impacts into a drought early warning system? 18

19 Drought Indices Percent of Normal Deciles Palmer Drought Severity Index (PDSI) Surface Water Supply Index (SWSI) Standardized Precipitation Index (SPI) Keetch-Byram Drought Index (KBDI) Vegetation Condition Index (VCI) And many more 19

20 Previous Workshops 20

21 Lincoln Workshop WMO OMM Inter-Regional Workshop on Indices and Early Warning Systems for Drought held in Lincoln, Nebraska, USA from 8 to 11 December 2009 Co-Sponsors: National Drought Mitigation Center (NDMC) United States Department of Agriculture (USDA) United States National Oceanic and Atmospheric Administration (NOAA) United Nations Convention to Combat Desertification (UNCCD) University of Nebraska-Lincoln, School of Natural Resources World Meteorological Organization 21

22 Workshop Objectives WMO OMM To review and assess drought indices currently used around the world for the three types of drought (meteorological, agricultural, and hydrological); To review and assess the strengths, weaknesses and limitations of existing drought indices and early warning systems; To develop a consensus standard index for each of the three types of drought; To develop guidelines for WMO Members in implementing and improving drought early warning systems. 22

23 Workshop Sessions WMO OMM Drought Indices and Early Warning Systems for Drought: An Overview Drought Indices in Current Use: Regional Perspectives (Africa, Asia, South America, North and Central America, South-West Pacific, and Europe) Impacts of Drought Hydrological and Agricultural Droughts Drought Monitoring: Current and Emerging Technologies Breakout Sessions to Develop Consensus Standard Indices for Different Types of Droughts 23

24 Breakout Groups WMO OMM Mostly followed methodology from Keyantash and Dracup (2002) The Quanification of Drought: An Evalution of Drought Indices Bulletin of AMS - August 2002 Used following criteria: Robustness Tractability Transparency Sophistication Extendability Dimensionality 24

25 Meteorological Drought Group Precipitation Percentiles (includes deciles and quartiles) Percent of Normal Precipitation Palmer Drought Severity Index (PDSI) Standardized Precipitation Index (SPI) 25

26 Meteorological Drought WMO OMM Indices Robust Tract Trans Soph. Extend. Dim. Sum SPI Percentile Ranking PDSI Percent of Normal Note: Percentile rankings include deciles and quartiles. 26

27 Meteorological Drought Outcome Standardized Precipitation Index (SPI) and Percentiles were very close, but the SPI had a slightly higher score Percent of Normal Precipitation was ranked third PDSI was a distant fourth Recommendation: Use drought indices that are based on a sound statistical and historical perspective (SPI and Percentiles). The SPI is the recommended Meteorological drought index. 27

28 Agricultural Drought Outcome No consensus (17 indices) Conclusions Water Balance models are quite good since they take into account soil and crop growth NDVI is very useful and is comparable with hydrological balance For all indices, a temperature component is important 28

29 Hydrological Drought Group WMO OMM Not well understood ~ complex Lags meteorological indices Basin specific Managed systems and unmanaged systems and interconnections (eg. northern Rocky Mountains and the Missouri river) Complicated by water scarcity (competition for resources on average years) Major changes in land use (or wild fires) can corrupt time series data Data hungry and not easy to calculate 29

30 Indices considered WMO OMM Reservoir Levels (unique to location/system and apatite for restrictions) Composite Hydro Index Low flow index (e.g. 7 day moving average inflow) % NRR type (departure from the mean) SPI as a surrogate in areas with sparse data 30

31 Hydrology Summary Table WMO OMM INDEX Robust. Tract. Trans. Sophis. Extend. Dimen. SUM Reservoir Level (managed) Percent Normal Rainfall SPI Composite Hydro Index Low Flow Index

32 Hydrological Drought Outcome No consensus (6 indices) Recommendations Examine composite indices that take into account streamflow, precipitation, reservoir levels, snowpack, groundwater levels such as: Surface Water Supply Index (SWSI) Aggregate Dryness Index (ADI) Normalised ADI (NADI) (Barua and Perera 2009) Also suggested; Streamflow drought Index (SDI) Nalbantis and Tsakiris (2009) Artificial Neural Networks (Perera et al. 2009) 32

33 Lincoln Declaration - Recommendations The National Meteorological and Hydrological Services (NMHSs) around the world are encouraged to use the SPI to characterize meteorological droughts and provide this information on their websites, in addition to the indices currently in use. A comprehensive user manual for the SPI should be developed that will provide a description of the index, the computation methods, specific examples of where it is currently being used, the strengths and limitations, mapping capabilities, and how it can be used. 33

34 Lincoln Declaration - Recommendations Two working groups with representatives from different regions and observers from UN Agencies and Research Institutions (and water resource management agencies for hydrological droughts) be established to further discuss and recommend, by the end of 2010, the most comprehensive indices to characterize agricultural and hydrological droughts. Recognizing the need to develop a framework for an integrated approach for drought monitoring to address all sectoral needs, a comprehensive study of consensus drought indicators is needed for potential global application. 34

35 Lincoln Declaration - Recommendations A simple, systematic analysis of drought impacts in different sectors should be initiated in all affected countries in order to provide useful decision-making information for policy-makers. Drought indices and early warning systems must be implemented from the beginning with the end-users in mind. To accomplish this goal, a multi-disciplinary approach incorporating user involvement is absolutely necessary. 35

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37 Recommendations from Murcia Given enhanced availability and access to data, tools, and guidance materials, meeting recommends that countries move beyond the use of just rainfall data in computation of indices for the description of agricultural droughts and their impacts. It is important to use more comprehensive data on rainfall, temperature, and soils in computing drought indices. Hence, greater cooperation is required between different ministries and agencies responsible for addressing drought issues at the sub-national, national, and regional levels. Recognizing that diverse data and information are required for the use of a composite approach (such as the U.S. Drought Monitor), the meeting recommends that all countries examine this option. 37

38 Current Actions The recommendation to use the SPI was approved by the WMO Executive Council in June 2010 and by WMO Congress in The UN International Strategy for Disaster Risk Reduction (ISDR) is providing funding for the meetings of the working groups on agricultural (June Spain) and hydrological (Sep Geneva) drought indices. With these recommendations, WMO contributed to ISDR on chapter on drought risks for the 2011 UN Global Assessment Report on Disaster Risk Reduction. 38

39 Other Initiatives WMO OMM Integrated Drought Management Programme High-Level Meeting on National Drought Policies 39

40 Proposed Integrated Drought Management Programme WMO and the Global Water Partnership are proposing an Integrated Drought Management Programme. Similar to APFM Targeting intergovernmental, governmental and nongovernmental organizations involved in drought monitoring, prediction, drought risk reduction and management. Primary beneficiaries are expected to be governmental institutions, agencies responsible for developing drought management policies and/or implementing systems for drought monitoring, prediction, preparedness and mitigation. The principal approach to develop global co-ordination of efforts to strengthen drought monitoring, risk identification, drought prediction and early warning services and development of drought management knowledge base. 40

41 Proposed Integrated Drought Management Programme (cont) The expected services to be provided are: Regional coordination of drought monitoring, prediction and early warning activities Inception of pilot projects and coordination of regional projects to showcase best practices Collection and dissemination of information and knowledge on good practices; Guidelines, methodologies, tools and supporting documentation on policy development and management practices and procedures; and Capacity building and advice on Integrated Drought Management. 41

42 Goals of National Drought Policy (1) WMO OMM Proactive mitigation and planning measures, risk management, public outreach and resource stewardship as key elements of effective national drought policy. Greater collaboration to enhance the national/regional/global observation network and information delivery system to improve public understanding of and preparedness for drought. Incorporation of comprehensive governmental and private insurance and financial strategies into drought preparedness plans. 42

43 Goals of National Drought Policy (2) Recognition of a safety net of emergency relief based on sound stewardship of natural resources and self-help at diverse governance levels. Coordination of drought programs and response in an effective, efficient and customer-oriented manner. 43

44 Why a HMNDP is needed? WMO OMM Despite the repeated occurrences of droughts throughout human history and the large impacts on different socio-economic sectors, no concerted efforts have ever been made to initiate a dialogue on the formulation and adoption of national drought policies. Amongst all the countries in the world, only Australia has a national drought policy which provides a clear description of when and how communities affected by droughts could seek drought relief under a legal framework. 44

45 Why a HMNDP is needed? (2) WMO OMM HMNDP could ensure that government actions transcend far beyond the conventional reactive approaches. In fact, it has been demonstrated traditional drought assistance or relief programs actually result in less self-reliance and more dependence on governments, increasing the vulnerability of sectors to future drought events. If more acceptable results are to be achieved while dealing with droughts, a new approach should be taken and new attitude adopted in dealing with droughts. 45

46 Why a HMNDP is needed? (3) A high level meeting could help develop such a new approach through developing a common understanding of the issues involved, discussing the different approaches that could be incorporated into a national drought policy and finally establishing a framework of a national drought policy that could help all the nations around the world. 46

47 Suggested Steps for Organization of HMNDP Seek the approval of the WMO Congress for this proposal (May 2011). Develop a comprehensive concept note on national drought policy through an Expert Meeting (July 2011) followed by meeting of the HMNDP International Organizing Committee (HIOC) (2011/2012). Organize a Symposium on Integrated Drought Information System (SIDIS) and refine the concept note further (Nov 2011). Engage diplomatic missions in Geneva to seek their comments on the concept note (Dec 2011); get comments from capitals (Feb 2012); revise the concept note and organize first meeting with missions (Feb 2012). 47

48 Suggested Steps for Organization of HMNDP (2) Organize second meeting of HIOC to discuss and finalize programme for HMNDP (March 2012) Organize second meeting with missions (May 2012), get their final endorsement of the revised concept note and programme for HMNDP. Organize the HMNDPI ( Nov-Dec 2012). 48

49 World Meteorological Organization Working together in weather, climate and water Thank You WMO