Drought and Precipitation Monitoring in the Caribbean

Drought and Precipitation Monitoring in the Caribbean SARI BLAKELEY, ADRIAN TROTMAN CARIBBEAN INSTITUTE FOR METEOROLOGY AND HYDROLOGY (CIMH) Caribbean l Water INTRODUCTION The Caribbean is highly susceptible to precipitation extremes, but until 2009 there was no systematic method to study past droughts or to forecast future ones. To meet this need, the Caribbean Drought and Precipitation Monitoring Network (CDPMN) was established as part of the Caribbean Water Initiative (CARIWIN), a cooperative agreement between the Caribbean Institute for Meteorology and Hydrology (CIMH), the Brace Centre for Water Resource Management at McGill University, and three pilot countries (Guyana, Grenada and Jamaica). A regional network hosted at CIMH, CDPMN centralizes data and indices for the monitoring of drought and wet episodes in the Caribbean. CDPMN has become an important platform for coordinating and addressing the needs of its diverse partners and stakeholders. The Caribbean Drought and Precipitation Monitoring Network serves several purposes. Linking national and local government organizations, the CDPMN collects drought and flood data and makes relevant information available to water managers, farmers, and citizens. Drawing on the broader network, CDPMN also identifies and monitors trends. This information is provided in a monthly update that is made available to the general public, and in more targeted outreach to the directors of 16 national meteorological offices in the region. CDPMN affiliates have been meeting with stakeholders to identify and fill capacity gaps, and to make suggestions regarding drought policy. SOCIOECONOMIC BACKGROUND The Caribbean region responds to changes in the sea surface temperature (SST) in the tropical Pacific, the north Atlantic and the north tropical Atlantic. The islands in this region are subject to fluctuations between precipitation extremes, which can have serious socioeconomic impacts on life in the region. Droughts result in major agricultural losses and adversely affect water resources, impacting all parts of life on island states. This was particularly evident between 2009 and 2010, when water resources in the Caribbean were critically depleted by a drought considered to be the worst on record for many impacted countries. This became a great burden for the agricultural community, which accounts for GDP for up to 31% and employs over 20% of the population in some members of the Caribbean Community (CARICOM) (Farrell, Trotman, & Cox, 2010); due to increased water utility bills, drought also affects the general public as well. Information provided by the CDPMN, including monitoring and forecast information, was instrumental in the formation of national response addressing the 2009-2010 drought throughout the region (Farrell, Trotman, & Cox, 2010). CDPMN information was also useful the next year, when unusually high levels of precipitation lead to flooding and mudslides, causing damage to houses, agriculture, and infrastructure. The sudden shift from drought to heavy rainfall stimulated stakeholder interest in the information provided by CDPMN, and allowed the network to quickly gain traction within the community. TARGET AUDIENCE The CDPMN program is part of the CARIWIN approach to Integrated Water Resources Management, which promotes an interdisciplinary approach to water management and encourages stakeholder input. Following these guidelines, CIMH has focused its efforts on reaching out to governments planning organizations so as to integrate water strategies into national planning, policy design and decision-making. CDPMN uses a participatory process to communicate the diverse needs of stakeholder communities. National meteorological offices and water authorities have become the main recipients of the initiative s climate information, which they use to make national-level policy decisions. That said, micro-level decision-makers, such as farmers, water resource managers, and the general public also have access to the drought forecasting information through CDPMN s website. CLIMATE AND CONTEXTUAL INFORMATION Several different climate processes influence the Caribbean climate. Long-term oscillations, such as the Atlantic Multi-Decadal Oscillation, AMO create sea surface temperature (SST) anomalies in the Atlantic Ocean. The positive phase of AMO, characterized by warm SST anomalies, is associated with increased precipitation in the Caribbean, while the negative phase is associated with drought. Seasonal SST variations in the equatorial Pacific Ocean (i.e., the El Niño Southern Oscillation, or ENSO) also influence the Caribbean. Through the CDPMN, CIMH gathers and compiles relevant climate information from regional meteorological offices throughout the region. Information is also provided by the European Center for Medium- Range Weather Forecasting (ECMWF), the International Institute for Climate and Society (IRI), and the UK Meteorological Office. Data and information are used to produce a number of drought monitoring and forecasting tools, including a Standardized Precipitation Index, Deciles and a Standard Precipitation Index Outlook, developed using the Caribbean Precipitation Outlook. The Climate Predictability Tool (CPT) is used to produce the Precipitation Outlook, which is then used to develop the Standardized Precipitation Outlook (SPI). The SPI compares current precipitation data to climatological precipitation data (on the order of 30 years or more) in order to identify drought. A negative index indicates drought conditions, whereas a positive index indicates wet conditions. As the dry or wet conditions become more severe, the index becomes more negative or positive. An index that approximates zero indicates normal precipitation levels. The CDPMN computes SPI at several time scales to capture the various scales of both short-term and long-term drought. In order to 1

monitor the potential effects of drought, indices based on the last onemonth of precipitation data provide a short-term analysis, which is useful for understanding the potential soil moisture composition and the stress that could be placed on crops. Measurements based on the last three months of data provide an indication of available moisture and are particularly useful at the beginning of the growing season. Meanwhile measurements based on six months of data can show the effects of rainfall distribution on stream flow and reservoir levels during a drought. Finally, indices based on twelve months of data are useful for predicting a potential long-term drought, which may impact groundwater availability. The tercile predictions of the Caribbean Precipitation Outlook are used in conjunction with the climatological distribution of rainfall data, and actual rainfall data to produce the Standardized Precipitation Index outlook. Essentially, the SPI Outlook provides a projection (as a range) of the SPI index value, based on the three tercile probabilities of the Precipitation Outlook. In addition to the SPI, a Precipitation Outlook is generated using the Climate Predictability Tool (CPT). Although not a direct product of CDPMN, it is used in conjunction with the SPI, the SPI Outlook, and the deciles to monitor drought conditions. Because the Caribbean is sensitive to ENSO, these forecasts are based on SST anomalies in the tropical Pacific; they rely on NOAA/NCDC Extended Reconstructed Sea Surface Temperature dataset made available by the IRI. In this case, the CPT uses SST and precipitation data from 1979 to 2011 to train the model and then uses the previous three months SST anomalies to generate forecasts for the following three-month period. This forecast generates probabilities for above-normal, normal, and below-normal precipitation. Table 1 illustrates an example of the SPI Outlook generated every month by CIMH through the CDPMN. For any month, the abovenormal, normal and below-normal indices 1 are generated by the SPI Calculator for a given station. Table 1: SPI and Precipitation Outlooks generated monthly by CIMH through CDPMN SPI Outlook Generated for the CIMH station for June 2012 1 month 3 month 6 month 12 month Probability Upper Boundary.38 to 2.17.19 to 3.30.12 to 3.27.65 to 2.73 25 Middle -.6 to.38 -.84 to.19 -.78 to.12.21 to.65 40 Lower Boundary -2.38 to -.6-2.85 to -.84-2.07 to -.78 -.3 to -.21 35 For the forecast based on one-month precipitation data, the upper boundary ranges from near normal (.38) to exceptionally wet (2.17), whereas the middle ranges from abnormally dry (-.6) to near normal (.38) and the lower boundary ranges from exceptionally dry (-2.38) to abnormally dry (-.6). The column on the far right is the forecast generated for the Precipitation Outlook by the CPT expressed in percent probabilities. Deciles are yet another monitoring tool being used in conjunction with the SPI. Both use the same precipitation information to summarize and analyze current precipitation conditions but deciles rank the rainfall data such that the lowest 10% of the rainfall values are in the first decile and the highest 10% are the tenth decile. 2 This provides users with a different way to understand the relative severity of any particular drought. Regional maps are already being created and are available on the website for users. Unfortunately, because many countries do not provide sufficient data to the CDPMN, national precipitation deciles are only currently available for Barbados. Once more countries provide comprehensive station data, decile maps and trends will be generated for other national outlooks. IMPLEMENTATION PROCESSES AND MECHANISMS STAKEHOLDER AND ISSUE IDENTIFICATION CDPMN set out to work with the stakeholders it identified when it was created under CARIWIN, intending to focus on the agricultural and water resource sectors. CIMH and McGill University identified these sectors because they are the groups affected most immediately by drought. CDPMN also has a list of prioritized users, such as health care institutions, emergency services, and diplomatic missions, which are entitled to water resources before anyone else, due to the importance of their work. While the regional entities were at first primary users, national meteorological offices and water authorities increasingly use the regional SPI to monitor drought. CDPMN hopes to see its information integrated even more into policies by hydrological offices, water utilities, ministries of health and national emergency management organizations. For the most part, farmers are unaware of the existence of CDPMN and therefore do not use this service in their decisions, and there is potential for the drought information to be used by a more diverse group of stakeholders, including the general public. 1 See the Appendix for detail regarding SPI classifications 2 See Appendix 2 for detail regarding decile classifications. 2

STAKEHOLDER INVOLVEMENT CDPMN is operated by CIMH, which manages all related project funds and allocates some of its budget to the project as well. Researchers at CIMH generate the drought monitoring information and the regional precipitation forecasting for CDPMN. CIMH is responsible for maintaining CDPMN s website, where it posts this information. 3 In the future, it is expected that CDPMN will mainly be used at the national level, which makes water resources, meteorological services, and disaster agencies key stakeholders. INFORMATION DISSEMINATION The stations precipitation data is sent directly to CIMH, which produces the SPI, deciles and SPI Outlook in an effort to centralize data, create indices for monitoring drought and abnormally wet periods, and provide an outlook of the future up to three months in advance. Two members of CIMH are primarily in charge of computing the forecasts and publishing them on the institute s website. Additionally, the directors of the various national ministries of agriculture, water resources, and meteorological offices are in direct, regular contact with the researchers at CIMH via email. During periods of drought, as evidence during 2010, CDPMN keeps authorities up to date with the latest forecasts and leaves a scrolling announcement on their website to warn all of its visitors as well. In the future, CDPMN imagines that other groups could help distribute information, such as schools, business, church and community leaders. INFORMATION TAILORING Through its website, CDPMN makes an effort to help users to interpret information. For example, the Precipitation Outlook (created by CIMH, but distributed through the CDPMN), SPI and deciles pages are accompanied by descriptions of how the forecasts are generated and how they should be interpreted. The site also includes an explanation of the outlook and their implications for the region, as well as an explanation of different climate factors that may be affecting rainfall, such as ENSO or AMO. FUNDING MECHANISMS CDPMN currently receives funding for training and awarenessraising through CARIWIN, a six-year project launched in 2007 and funded through the Brace Centre for Water Resource Management at McGill University. This funding is made available from the Canadian International Development Agency (CIDA). CDPMN is currently in its pilot phase, which will conclude at the end of 2012. CIMH also provides in-kind support for CDPMN by means of personnel; funds are also allocated from the Caribbean Meteorological Organization (CMO). At the end of 2012, when CDPMN wraps up the pilot phase of its development, CIDA funding will no longer be available. Instead, CIMH will partner with the UN Food and Agriculture Organization of Brazil to support CDPMN, which will provide USD $70,000 for the year. These funds will help CIMH to downscale the regional monitoring and forecasts to a national level; pilot activities all already underway in Jamaica, Grenada, and St. Lucia. It is expected that this tailoring is likely to bring in more funds for drought and precipitation forecasting from countries interested in continuing CDPMN services. In the more distant future, it is unclear where funding will come from, how stable it may be, or if a shift in its source will push CDPMN to change significantly. It is hoped that the funding for CDPMN will be stable, since it is the only source of information for drought monitoring and prediction in the Caribbean, and its important mitigation role in the 2009-2010 drought won it so much attention from Caribbean governments and their national meteorological offices. MANAGEMENT AND DECISION MAKING CDPMN was created as part of CARIWIN. Since CARIWIN was established as a joint project with McGill University, the original proposal was approved by the administration. At this point, CIMH has almost complete autonomy in managing CDPMN and making decisions. CDPMN s work is strengthened through CIMH s partnership with various Caribbean government agencies, in particular national meteorological services and educational institutes, which send meteorological information, use CDPMN s drought information, and provide feedback on the site. Stakeholder decision making informed by CDPMN happens in a variety of ways, as demonstrated by the 2009-2010 drought. During this time, the information provided by CDPMN proved to be accurate and became highly valued by regional governments. Once the severity of the potential drought was recognized, CDPMN contacted affected governments and issued an alert on their website. The governments of Grenada and Barbados asked CIMH to issue warnings to their public. Governments used the drought information provided by the CDPMN in different ways. In Grenada, for instance, the Ministry of Agriculture partnered with the National Water And Sewage Authority and the National Disaster Management Agency to promote water conservation, through radio, television, press conferences, print media, and educational programs. Many water tools, including as hoses, were outlawed to prevent car washing and other unnecessary uses 4of water. Several countries issued water rationing and water-use laws. EVALUATION CIMH gathers feedback on the CDPMN from a diverse set of stakeholders throughout the Caribbean. It organizes and holds workshops, bringing together ministries of agriculture, water authorities, meteorological offices, and national disaster management agencies, as well as representatives from CARIWIN communities, discussing in particular the evolution and impacts of the 2009-2010 drought. These workshops include trainings, presentations, and round table discussions in order to allow participants to learn more about the CIMH projects and provide feedback. Teaching participants to better use available tools is an important part of the workshops, as is gathering information on how the tools on the site, and the site in general may be improved. Workshops have helped CIMH to gain a better understanding of how to make its information more accessible to the general public. National meteorological offices also have direct contact via email and phone calls with the institute, which allow them to articulate their needs and expectations. As a result of these interactions, CIMH has continually updated its webpage to make it more user-friendly, adding features such as the scrolling announcements, and in-depth explanations of forecasts. 3 Please visit http://www.cimh.edu.bb/?p=home to visit CIMH s website 4 Conversation held with former Director of Grenada Meteorological Office, John Peters 3

CAPACITIES EXISITING CAPACITIES CIMH researchers have played a key role in developing CDPMN; in recent years, however, other countries have started to participate as well. Prior to 2012, the forecasts for the Precipitation Outlook were created solely by the CPT prediction generated at CIMH. However, as of 2012, CIMH has incorporated input from several countries to generate a consensus forecast. This broader participation is an asset for the CDPMN, which uses the Precipitation Outlook on its site. As national networks become established the capacity will be increased, as these national agencies will form part of the regional network. There are however capacity concerns within CIMH and the national agencies. Many persons perform the activities of both CDPMN and the Precipitation Outlook on their own time out of interest in, and the importance of, the activity and outputs. CAPACITY GAPS CDPMN is an evolving service, and there are several ways in which it could be improved. First, the SPI Outlooks is relatively difficult to understand. The SPI is generated using a SPI calculator, with projected rainfall from climatological data fitted to historical rainfall according to the four time scales and is divided into 3 tercile ranges. The boundaries for the tercile ranges are used to project the boundaries of the index. The changing index is difficult to understand as opposed to changing the probabilities for a standardized, static index. Also, it is not immediately apparent that the 1-, 3-, 6-, and 12-month indices are all forecasts for the same month generated from different data. Although the website offers an explanation on how to read the outlooks, the technical information is not easily understood by the average user, though it may be useful to users who already possess meteorological knowledge. Another central challenge is that SPI Outlooks have not been validated. Researchers at CIMH are working to create hindcasts for the SPIs Outlooks, 5 but there are several datasets that are missing dates or have only partial time series. This has complicated the process. As a result, it is hard for the user to know how reliable the Outlooks are. Additionally, though Precipitation and SPI Outlooks are generated regionally, national outlooks would be very useful as well. This would require countries to consistently contribute more data to the project, however, which has proved difficult. There may also be capacity issues that limit the production of national outlooks. LOOKING TOWARD THE FUTURE GOALS The use of SPIs and Deciles were instrumental in assessing the severity of the 2009-2010 drought, and has been employed ever since, but CDPMN still needs to validate these indices CDPMN is comparing SPI and Deciles to other drought indices, the Palmer Drought Severity Index (PDSI) and the Standardized Precipitation Evaporation Index (SPEI), but the comparison is not yet finished. Currently, CDPMN generates outlooks for the upcoming three months (SPI Outlook) 5 Please visit http://www.cimh.edu.bb/?p=home to visit CIMH s website based on four different timescales for the dataset. The next step for CDPMN is to create longer-range forecasts to give decision makers and users a better idea of the distant future. However, this is a difficult goal to achieve since it requires more information and rigorous validation of the methods used, and cannot be accomplished until the SPI has been validated and its efficiency verified. PROJECT EXPANSION CDPMN hopes to offer national as well as regional outlooks. It also hopes that other countries in the Caribbean that are not a part of CMO will begin to contribute their data in order to create a more robust regional outlook. Non- Caribbean Meteorological Organization (CMOan organization of 16 Caribbean nations to promote and coordinate regional activities in meteorological sciences) states, including the Dominican Republic and Cuba, also contribute to the regional products. CIMH is in the process of creating a centralized data system that could automatically update the information from all involved stations. This would make accessing the information simpler and facilitate the creation of the SPIs, Deciles and SPI Outlooks. In order to make such a centralized system possible, CMO and non-cmo countries would need to contribute national meteorological information. This would require CIMH to work more closely with governments to monitor the weather and use the climate information to predict the SPI, Deciles and other indices and indicators. LESSONS LEARNED Although still in its infancy as a service, CDPMN has provided the Caribbean community with an opportunity to learn more about the successful provision of climate information. To begin, CDPMN has revealed the extent to which regional climate factors must be understood to produce appropriate forecasts. Prior to 2009-2010, the majority of the region was unaware that a drought of such intensity, and impacts created, were possible. CDPMN was able to create a way of monitoring and predicting drought. Although the resources for CDPMN were limited, it was still able to produce information that was useful and incorporated into many governments decisions. In addition to its practical utility, a service such as CDPMN can play an important role in drawing public attention to problems like drought that may have been inadequately handled previously. Affected governments are using the CDPMN s service to create policies and formulate action plans for the next extreme drought. Another important lesson has to do with CDPMN s ability to scale and provide tailored information being dependent upon its users. Although national forecasts would be very useful, CDPMN is unable to provide them unless it can get long-term precipitation data. This illustrates the need for more data sharing between climate service institutions and governments. Additionally, although there is data available in some countries, the communication of this data to CIMH is not always promptly given, which hinders the production of timely climate information. THE WAY FORWARD CDPMN has improved since it was created in 2009. It has proved useful during and acted as a major catalyst in the development of policies throughout the Caribbean. However, there are challenges in its future development. Even though CDPMN is confident about its utility in the region, the question where funding will come from after 2012 is uncertain. Another issue is that CDPMN must be validated, as both the comparison indices and the generation of national forecasts requires a lot of data. 4

PRINCIPLES OF THE GFCS Principle 1: Principle 2: All countries will benefit, but priority shall go to building the capacity of climate-vulnerable developing countries. All Caribbean countries are vulnerable to climate change, and CIMH works with as many as are willing to participate. Climate change threatens to exacerbate both the strength of hurricanes and the intensity of droughts. The primary goal of the Framework will be to ensure greater availability of, access to, and use of climate services for all countries. CIMH s primary mission is to offer climate information to Caribbean countries. For CDPMN, this means that the website is updated monthly with the status of rainfall (and as national networks develop in the future, water availability and resource), outlooks, interpretation of these, and scrolling alerts when the region faces drought. This makes the information available for all users. Finally, CIMH is in contact with the meteorological offices directors of sixteen CMO member countries, and sending them warnings and advice when necessary. Principle 3: Framework activities will address three geographic domains; global, regional and national CDPMN is a service geared towards those in the Caribbean, and therefore incorporates global factors to monitor climate and create forecasts and allows for national interpretation through the use of station data. The service also is intent on forming national networks for information flow. Principle 4: Operational climate services will be the core element of the Framework. CDPMN s intent is to make climate information available to decision makers so that they can prepare for climate variability and mitigate damages. Principle 5: Climate information is primarily an international public good provided by governments, which will have a central role in its management through the Framework. Principle 6: The Framework will promote the free and open exchange of climate-relevant observational data while respecting national and international data policies. CDPMN offers all of its knowledge for decision makers for free. Principle 7: The role of the Framework will be to facilitate and strengthen, not to duplicate. CDPMN is generating new information. Before 2009, no other institute was researching how to monitor and predict droughts and floods and influence policy and planning decisions in the Caribbean. Principle 8: The Framework will be built through user provider partnerships that include all stakeholders. The website was built as a result of engagement with stakeholders who were faced with the potential catastrophic overflow of Devils Lake. Other partners were engaged to provide the maximum benefit for stakeholders. For example, geographically relevant data from and links to other agencies are available on the DSS for use by Devils Lake decision makers. 5

APPENDIX 1: ABBREVIATIONS AMO- Atlantic Multidecadal Oscillation CARICOM- Caribbean Community CARIWIN- Caribbean Water Initiative CDPMN- Caribbean Drought and Precipitation Monitoring Network CIDA- Canadian International Development Agency CIMH- Caribbean Institute for Meteorology and Hydrology CMO- Caribbean Meteorological Organization CPT- Climate Prediction Tool ENSO- El Niño Southern Oscillation GFCS - Global Framework on IRI- International Research Institute for Climate and Society IWRM- Integrate Water Resource Management NADMA- National Disaster Management Agency, Grenada NAWASA- National Water And Sewage Authority, Grenada NOAA- National Oceanic and Atmospheric Administration NWIS- National Water Information System, Grenada PDSI- Palmer Drought Severity Index SPI- Standardized Precipitation Index SST- Sea Surface Temperature UWI- University of West Indies 6

APPENDIX 2: DECILE CLASSIFICATION Deciles Implications for rainfall Percentage of rankings Decile 10 Very Much Above Average Highest 10% Decile 8-9 Above Normal Next Highest 20% Decile 4-7 Normal Middle 40% Decile 2-3 Below Normal Next Lowest 20% Decile 1 Very Much Below Normal Lowest 10% APPENDIX 3: DECILE MAPS Barbados Decile Maps, an example map for national deciles generated in October 2009 for October 2009 7

Precipitation Outlooks, first map generated in June 2012 for June-July-August 2012, second map generated in May 2012 for May-June-July 2012 Regional Decile Maps generated in May 2012 Regional SPI Outlooks generated in May 2012 8

APPENDIX 4: MEMBER COUNTRIES IN THE CMO Anguilla British Virgin Islands Guyana St. Lucia Antigua and Barbuda Cayman Islands Jamaica St Vincent and the Grenadines Barbados Dominica Montserrat Trinidad and Tobago Belize Grenada St Kitts/Nevis Turks and Caicos Islands APPENDIX 5: SPI CLASSIFICATION SPI Value Classification -2.01 Exceptionally Dry -2.00 to 1.61 Extremely Dry -1.60 to -1.31 Severely Dry -1.30 to -.81 Moderately Dry -.80 to -.51 Abnormally Dry -.50 to.50 Normal.51 to.80 Abnormally Wet.81 to 1.30 Moderately Wet 1.31 to 1.60 Severely Wet 1.61 to 2.00 Extremely Wet 2.01 Exceptionally Wet 9