IBTrACS: A Collaborative Effort to Consolidate Tropical Cyclone Best Track Data Worldwide

Transcription

1 IBTrACS: A Collaborative Effort to Consolidate Tropical Cyclone Best Track Data Worldwide Kenneth R. Knapp and Howard J. Diamond World Data Center for Meteorology Global l Disaster Risk Reduction Introduction The International Best-Tracks Archive for Climate Stewardship (IBTrACS) 1 provides tropical cyclone best-track information on a global scale. IBTrACS functions under the auspices of the World Data Center for Meteorology (WDC) and aims to make data available in a centralized location so as to further our understanding of the distribution, frequency, and intensity of tropical cyclones worldwide. In combining track and intensity estimates from many sources, this consolidated collection of tropical cyclone data provides an extensive global climatology and insight into data uncertainty, which is a critical consideration for climate trending (Knapp et al. 2010). The IBTrACS project: Contains the most complete global set of historical tropical cyclone data available Combines information on individual storms from numerous tropical cyclone datasets in one place for easier comparison. Provides data in popular formats to facilitate analysis Checks the quality of storm inventories, positions, pressures, and wind speeds Passes the information on to the user in various digital formats Socioeconomic Background Tropical cyclones (TCs) have a significant impact on human life, property, and ecology. Small islands, for example, are particularly prone to natural disasters caused by TCs. Small islands also share many distinctive characteristics that increase their sensitivity and vulnerability to climatic factors: In addition to their small physical size, they are surrounded by large expanses of ocean and are relatively isolated from world economic markets. A great deal of research has therefore gone into understanding the distribution, frequency, and intensity of TCs around the world and the ways in which climate change might affect these parameters (CCSP 2008; Chan 2006; Klotzbach 2006; Landsea 2005; and Webster et al. 2005). The impacts caused by varying frequencies and intensities of extreme weather, climate, and sea level events are very likely to change, which further intensifies vulnerability around the world (Parry et al., 2007). Since 1950 in the southwest Pacific, for example, natural disasters have affected more than 3.4 million people and caused over 1,700 reported fatalities in the region (excluding Papua New Guinea). TCs accounted for 76% of the reported disasters worldwide from 1950 to 2004 (World Bank, 2006). Target Audience The audience for this data ranges from the operational Regional Specialized Meteorological Centers (RSMCs) and forecasters, to climate researchers at universities and other institutions, students, insurance companies, coastal planning agencies, and everyday citizens interested in learning more about TCs. Climate and contextual information IBTrACS takes a transparent, unbiased, and strictly scientific approach to building its service, which is maintained at the highest possible quality to meet the majority of needs among users and stakeholders. Various common storm characteristics can be used to define the ways in which an individual storm can impact life and property. These include maximum sustained wind (MSW), the distance at which various wind speeds extend outward from the storm center, rainfall patterns, minimum sea level pressure (MSLP), and storm translation speed. Despite the many facets of a storm, most TC data consist of best estimates of a storm s position and intensity at 6-hour intervals. A series of 6-hour data points is termed tropical cyclone best-track data and is the basic kind of information used in IBTrACS (Knapp, et al. 2010). As defined by the US National Oceanic and Atmospheric Administration s (NOAA) National Hurricane Center, 2 best-track data are a subjectively smoothed representation of a tropical cyclone s location and intensity over its lifetime and generally will not reflect the erratic motion implied by connecting individual center fix positions. Given this subjectivity, the amount of spatial smoothing will vary among agencies. IBTrACS takes two approaches to providing TC data. One is known as the WMO format 3 (IBTrACS-WMO) and is strictly limited to the official best-tracks data provided by the RSMCs. For the first time, IBTrACS has taken TC best-track information from 12 RSMCs and TCWCs from around the world and consolidated that information into a single, quality-controlled, and readily available dataset. The WMO Tropical Cyclone Programme has endorsed IBTrACS as an official archiving and distribution resource for tropical cyclone best track data

2 The second approach is known as IBTrACS-ALL and incorporates information from other agencies in addition to RSMC data. These agencies include, but are not limited to, the Joint Typhoon Warning Center, China Meteorological Agency as well as data from other research agencies (e.g., Hong Kong Observatory) and individual researchers (e.g., Neumann). Table 1 summarizes the differences between IBTrACS-WMO and IBTrACS-ALL data: Table 1: WMO versus ALL approaches to data tracking. Differences between the sets are highlighted in bold type. IBTrACS-All IBTrACS-WMO Summary Best track data as provided by all agencies and dataset sources. Best track data only from WMO-sanctioned forecast agencies Parameters (as available) Position Maximum sustained winds Minimum central pressure Storm name Radius of maximum winds Radius of outermost closed isobar And more as provided by each agency Position Maximum sustained winds Minimum central pressure Storm name Washington University RSMC Miami RSMC Honolulu RSMC Tokyo RSMC New Delhi RSMC La Reunión RSMC Nadi TCWC Perth TCWC Darwin TCWC Brisbane TCWC Wellington CMA-Shanghai Typhoon Institute Joint Typhoon Warning Center Hong Kong Observatory NCDC DSI-9636 UCAR ds824.1 RSMC Miami RSMC Honolulu RSMC Tokyo RSMC New Delhi RSMC La Reunión RSMC Nadi TCWC Perth TCWC Darwin TCWC Brisbane TCWC Wellington # of intensity reports per observation time Numerous (as many reports as agencies tracking the system) One (from the official WMO agency) Formats netcdf Comma Separated Variables (CSV) netcdf Comma Separated Variables (CSV) HURDAT format WMO format cxml ATCF 2

3 Data are updated at a minimum on an annual basis and are provided in various formats, some of which are utilized by specific user communities. For example, data are provided in: Cyclone extensive markup language (cxml), which is a format used by the modeling community GIS shapefiles, which is a format used mainly by planners and managers who compare past events with other GIS information (e.g., land use, roads, population, etc.) Comma separated variable (CSV) format, which allows for easy incorporation into databases and spreadsheets IBTrACS data are also provided in other formats that are used throughout the tropical cyclone research community. IBTrACS best-track data are also used to define probability distributions for characteristics of tropical cyclones (e.g., forward motion and intensity) in a risk model, which can in turn be used for a number of analyses relevant to decision making. Economic evaluation, for example, produces normalized datasets that estimate the probability of future losses and costs incurred by tropical cyclones. Risk models are made of three basic components: a hazard component, a damage component, and a loss component. The hazard component provides the probabilities and characteristics of a specific hazard. For a tropical cyclone, it would provide information such as storm track, forward motion, wind field, and decay over land. The damage component of the risk model uses this information to calculate the expected damage, and the loss component estimates costs associated with rebuilding, loss of business, and the liability of a specific company. Good and reliable best-track information for tropical cyclones is key in the decision-making processes of a range of users: The re-insurance industry, for example, uses the information to calculate the risk of providing backup to front-line insurance companies. Coastal planners use IBTrACS information to evaluate the ways in which they can use historical information to make decisions regarding evacuation route planning, reservoir water levels, coastal erosion, etc. Meanwhile, decision-support systems such as Tropical Cyclone Information Processing System (TIPS) could make use of a global dataset like IBTrACS data to facilitate decision making in forecasting and early warning operations. TIPS, which was developed by the Hong Kong Observatory in Hong Kong, China, serves four main functions: 1) To integrate all tropical cyclone-related data for display, including satellite/radar fixes and imageries, forecast tracks from warning centers, and forecast tracks derived from numerical weather models; 2) To assimilate track data for computation of an ensemble track for operational forecasting; 3) To compute key parameters for evaluating local impact to facilitate warning decisions; and 4) To generate and dispatch forecast and warning products to the local public and other weather centers. The system has been in operation since Forecasters at the Hong Kong Observatory find TIPS to be user-friendly and indispensable in TC forecast and warning operations. Lastly, NASA s SERVIR program in Central America 4 has recently demonstrated applications related to adaptation that utilize the IBTrACS data program. SERVIR integrates satellite observations, ground-based data, and forecast models to monitor and forecast environmental changes and improve response to natural disasters in Central America, the Caribbean, Africa, and the Himalayas. It helps inform science-based decision making in the areas of climate change, health, agriculture environment, water and weather. Implementation Processes and mechanisms Stakeholder and issue identification In April 1998 in Hainan, China, the Warning Process sub-group of the Tropical Cyclone Impact Group at the Fourth International Workshop on Tropical Cyclones (IWTC-IV) recommended the development of improved and enhanced best-track data. This recommendation was critical in the formation of IBTrACS. An internal requirement at the NCDC-World Data Center for Meteorology for a global best-track dataset was also critical. Rather than developing a dataset that solely met the needs of the NCDC-WDC, however, the IBTrACS team began working with tropical cyclone scientists. The entire IBTrACS project began as a grassroots effort and evolved through collaboration with the WMO TC Programme, as well as the coordination of a wide variety of users via an online Tropical Storms mail listserv. Decisions were made collectively by the IBTrACS team based on published papers (Kruk and Knapp, 2012; Knapp et al. 2012), interaction with users and the tropical cyclone research community at scientific conferences, and the experience of individuals involved in TC best-tracks work. The World Data Center for Meteorology is part of the new International Council for Science s World Data System, 5 which aims for full and open sharing of data. It was therefore decided the IBTrACS would be organized under that banner. Today, there are several institutional stakeholders involved in supporting IBTrACS work. The IBTrACS program is supported by the World Data Center for Meteorology, Asheville, North Carolina, United States, which is maintained by the US Department of Commerce (DoC) and the US National Oceanic and Atmospheric Administration (NOAA). IBTrACS is collocated with and operated by the National Climatic Data Center (NCDC) in Asheville, and the WMO TC Programme was involved as a collaborator throughout IBTrACS s development and evolution. Stakeholders that rely on IBTrACS for information come from several different user-group sectors including evacuation planners, RSMCs, forecasters, researchers, students, and insurance providers. All users are asked to register for the data they wish to access. In doing so, they are automatically made a member of the IBTrACS community where they can both receive and contribute information to the overall project effort. User input and feedback on dataset issues and usage is requested regularly. Furthermore, user input is used to justify and make further improvements to the data. A number of data providers also have stake in the IBTrACS effort. Data is provided by a number of RSMCs (Miami, Honolulu, Tokyo, New Delhi, La Reunión, and Nadi) and TCWCs (Perth, Darwin, Brisbane, and Wellington), along with Joint Typhoon Warning Center, China Meteorological Agency, Korea Meteorological Administration; as well as data from other research agencies (e.g., Hong Kong Observatory) and individual researchers (e.g., Neumann). 3

4 Stakeholder involvement Data is provided by a number of RSMCs (Miami, Honolulu, Tokyo, New Delhi, La Reunión, and Nadi) and TCWCs (Perth, Darwin, Brisbane, and Wellington), along with the Joint Typhoon Warning Center, China Meteorological Agency, Korea Meteorological Administration and data from other research agencies (e.g., Hong Kong Observatory) and individual researchers (e.g., Neumann). The IBTrACS team then combines the information from various datasets, simplifies interagency comparisons, and makes the data accessible to end-users in several different digital formats. Essentially, IBTrACS serves as an intermediate communicator between the data providers and end-user community. The IBTrACS workshops in particular provide a platform for dialogue between sectors. The data providers - national and international agencies - offer guidance regarding the proper use and processing of their dataset. In turn, IBTrACS presents user requests to those providers. In this way, IBTrACS can advocate for the users to the agencies and speak to the users on behalf of the agencies. The information that goes into IBTrACS is generally made available by either File Transfer Protocol (FTP) connection or . While the data are not voluminous (i.e. when file sizes are smaller), they are easily transported in digital form. Once the IBTrACS team compiles the data, they are made available at no cost and in a variety of formats including netcdf, Comma Separated Value (CSV), and ArcGIS. Funding mechanisms The IBTrACS business model follows that of NOAA s National Climatic Data Center (NCDC), which also hosts the WDC. Essentially this involves providing the highest quality climate data products possible within existing resource constraints. That is, the IBTrACS program itself does not have its own stream of funding, but rather exists by leveraging with other activities at NCDC, including the U.S. Global Climate Observing System Program. 6 IBTrACS relies on limited resources to ensure that the effort can continue to serve the customers and stakeholders it has acquired over the past years. management and decision making As noted earlier, the IBTrACS service involves input from a number of international partners and organizations. While they have no formal role in the management of IBTrACS (the effort is too small for that type of involvement), these partners do have a large say in how IBTrACS is structured and how decisions are made by the IBTrACS team to try to meet the needs of all users within the financial constraints at hand. This is done in several ways. First, partner must register for the dataset, which also allows the IBTrACS team to communicate with them. Second, partners must have an address at IBTrACS. Team@noaa.gov, which provides an avenue for users to provide feedback. Finally, partners have access to a global tropical storms forum, which gives them the opportunity to provide feedback and communicate with the IBTrACS team. Ultimately, all decisions concerning the project are made by consensus of the team. Criteria used in making decisions include: would it benefit users? Is the process/decision scientific? Those were the driving forces behind the development of the IBTrACS initiative and are still the motivating factors behind the project today. evaluation IBTrACS is evaluated and input is solicited annually with the announcement of that year s updated product. However, evaluation it is not limited to a yearly basis. The IBTrACS team is always open to input from users and data providers and aims to put forth the best service possible. IBTrACS encourages users to share their activities and uses of the service, which demonstrate the value of IBTrACS s work across the spectrum of climate science, including, but not limited to facilitating adaptation to climate change. IBTrACS primarily receives advice and input from its users at the IBTrACS workshops, where an array of international stakeholders come together to for discussion. Thus far, there have been two international IBTrACS workshops staged in Asheville, North Carolina in spring 2009 and a third workshop in Honolulu, Hawaii held in April Also, as stated above, we often request and receive user feedback via contact with users via . Capacities Existing capacities The National Climatic Data Center (NCDC), which promotes the provision of services to the climate community, was a major asset to the development of IBTrACS. Supported by NCDC s many years of experience, IBTrACS had the human, infrastructural, institutional, and procedural capacities (e.g., servers, web access, experience in building climate datasets, data stewardship, etc.) necessary to build the IBTrACS service. The IBTrACS team members also had the necessary scientific and programming experience that comes with years of working in the field. Their background was essential in establishing this type of effort. Scientists are particularly enthusiastic because of the freedom offered by this kind of activity, and the IBTrACS team is acutely aware of the uniqueness of the opportunity. Capacity gaps IBTrACS s global coordination of the best-tracks data is complicated by instances in which there is overlapping coverage for the same basin. In these cases, conflicts must be settled in the best interest of the community. Resources are also a constant issue, and while the IBTrACS team would ideally have a full-time dedicated staff to maintaining the IBTrACS project, that is simply not possible. That said, the IBTrACS team recognizes that all such services are under stress, and it just takes greater flexibility to ensure that activities like IBTrACS can continue. The IBTrACS Team recognized early on that if best-track data were to be utilized widely throughout the end-user community, it would be necessary to provide the data in formats already in use rather than in a new format only. To encourage early adoption and use of the IBTrACS data, the team therefore provided information in many of the common best-track formats. This has been a large part of IBTrACS s success

5 Looking toward the future Goals The goals for the future of IBTrACS are simply to continue providing updated information on an annual basis and improve online access to information whenever possible. If resources were available, the IBTrACS team would like to look into producing more user-oriented products (e.g., tailored maps, mobile devices). However, this type of expansion will depend on the support and collaboration of other parties (e.g., universities, students, companies). IBTrACS success will be measured by its longevity and its continued ability to annually collect, coalesce, and distribute to global users the data upon which they have come to depend. Project expansion As is the case in any program, more things could be done throughout the development of the IBTrACS initiative. Additional storm characteristics such as the radius of maximum winds, maximum gusts, and rainfall would improve the depiction of tropical cyclones by the hazard component of a risk model, lead to more realistic estimates of future losses and costs, and improve estimates of the benefits of mitigation efforts (Anaman, et al, 1997). Particular emphasis could be put on scaling up the project on the side of new products and applications. lessons learned To encourage early adoption and use of the IBTrACS data, the team provided information in many of the common best-track formats. This has been a large part of IBTrACS s success. The greatest lesson learned in the IBTrACS case is simply in the power of collaboration and the use of a science-based approach to identify and fulfill a need. The driving force behind the success of IBTrACS has been its bottomup grassroots strategy, in which scientists and users work together to develop a service that serves the widest range of users possible. the way forward IBTrACS success will be measured by its longevity: the continued ability to annually collect, consolidate, and distribute data to users around the globe.in a resource-constrained environment, the greatest challenges are to continue the existing IBTrACS effort, work to improve access to data, and develop new applications and related products. Ultimately, IBTrACS must continue to serve the diverse community of users who have come to depend on it for their needs with respect to tropical cyclone best-track data. 5

6 Principles of the GFCS IBTrACS addresses all of the principles of GFCS, as is demonstrated in the above description. Principle 1: Principle 2: All countries will benefit, but priority shall go to building the capacity of climate-vulnerable developing countries. The primary goal of the Framework will be to ensure greater availability of, access to, and use of climate services for all countries. Principle 3: Framework activities will address three geographic domains; global, regional and national Principle 4: Operational climate services will be the core element of the Framework. 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. Principle 7: The role of the Framework will be to facilitate and strengthen, not to duplicate. Principle 8: The Framework will be built through user provider partnerships that include all stakeholders. References Anaman, K.A., Lellyett, S.C., Drake, L., Noar, P.F., Sullivan, P.J., Henderson-Sellers, A.,Thampapillai, D.J., 1997: Economic and Social Benefits of Meteorological Services provided by the Australian Bureau of Meteorology. Macquarie University/Bureau of Meteorology Final Project Report. CCSP, 2008: Weather and climate extremes in a changing climate Regions of focus:north America, Hawaii, Caribbean, and U.S. Pacific Islands. U.S. Climate Change Science Program Synthesis and Assessment Product 3.3, National Climatic Data Center, 164 pp. Chan, J. C. L., 2006: Comment on Changes in tropical cyclone number, duration, andintensity in a warming environment. Science, 311, 1713, doi: / science Klotzbach, P. J., 2006: Trends in global tropical cyclone activity over the past twenty years ( ). Geophys. Res. Lett., 33, L10805, doi: /2006gl Knapp, K.R., M.C. Kruk, D.H. Levinson, H.J. Diamond, and C.J. Neumann, 2010:The International Best Track Archive for Climate Stewardship (IBTrACS). Bull. Amer. Meteor. Soc., 91, ; doi: /2009BAMS Kruk, M. C., K. R. Knapp, and D. H. Levinson, 2010: A technique for combining global tropical cyclone best track data. Journal of Atmospheric and Oceanic Technology, 27, Landsea, C. W., 2005: Hurricanes and global warming. Nature, 438, E11 E13. Parry, M.L., O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson (eds). Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge, United Kingdom and New York, NY, USA. Webster, P. J., G. J. Holland, J. A. Curry, and H.-R. Chang, 2005: Changes in tropical cyclone number, duration, and intensity in a warming environment. Science, 309, World Bank, 2006, Not if, but when. Adapting to natural hazards in the Pacific Islands region; A policy note, The World Bank, East Asia and the Pacific Region, Pacific Islands Country Management Unit, Washington, D C, 46 pp. 6