Cyclone Center first results published; Can Citizen Scientists Improve Tropical Cyclone Intensity Records?


One of the key questions in climate science is how has the climate changed? The historical observations are the very foundation of our ability to understand and ultimately predict climate processes. Now, you can help the scientific community to reanalyse changes in tropical cyclones over the past 30 years!


One absolutely key aspect to the evidence basis is the evidence for extreme events such as tropical cyclones (typhoons, hurricanes). Sadly, the historical global tropical cyclone record is a mish-mash of official historical season-end retrospective analyses from numerous official forecast centres around the world. These analyses are based upon in-situ, aircraft and, especially for portions of cyclones that are distant from land, satellites. There exists a set of ‘rules’ to define strength based upon image characteristics. But staff at forecast centres have come and gone and centres have interpreted the rules in subtly different ways over the last 30-something years.

So, there does not exist a long-term globally homogeneous record of tropical cyclone intensities even over the period of globally complete satellite observations. Yet such a record is essential if we are to answer questions about whether the number of intense storms has changed or whether their cumulative power has changed or myriad other important questions about these beautiful, powerful, and ultimately destructive phenomena.

Cyclone Center is a citizen scientist project hosted by the Citizen Science Alliance. Its objective is to use the time, skills and dedication of volunteer citizen scientists (like you) to reanalyze global tropical cyclone intensity estimates over a large portion of the satellite era. This uses a simplified approximation to the ‘rules’ used by experts that still provides extremely valuable information. Indeed, today the first paper analysing the results by the international team of scientists supporting the project has been published online in the Bulletin of the American Meteorological Society. Nansen Center senior scientist Dr. Peter Thorne is one of the initiators of the Cyclone Center and co-author of this paper in BAMS.

The paper Cyclone Center: Can Citizen Scientists Improve Tropical Cyclone Intensity Records? shows first and foremost that the volunteer citizen scientists have been making very reasonable and realistic classifications of cyclone strength using Cyclone Center. So, if you get involved then rest assured you will be making a valuable contribution. In particular there is no substitution for the human eyes in recognizing complicated patterns inherent in much cyclone imagery. Cyclone Center volunteers appear in particular to do a better job then automated techniques at getting the critical transition from weak to strong storms.

Users are guided through a set of questions to appropriately assign the cyclone intensity.Users are guided through a set of questions to appropriately assign the cyclone intensity.As if the value of having human reanalysis rather than relying upon automated procedures was not enough, a unique strength of Cyclone Center is having many pairs of human eyes on each and every image. This allows us to get a better handle on how certain we can be through the spread of individual classifications of each and every image. When combined with appropriate requirements on intensification to create many possible storm intensity series we can really start to identify when the storm evolution was more or less certain.

Having many classifications of all images across all basins and years will enable a more consistent analysis globally and through time. There are many thousands of images, so it’s unrealistic to get a single analysis by one individual expert. Even if we did manage that we’d still have no indication of the plausible range so we’d have to then get ten more people to do the same. That would be in excess of 20 person years of expert and that’s if we didn’t give them weekends or public holidays off. By tapping the interest of thousands of citizen scientists, getting each image analyzed several times over under a consistent framework and all answering the same questions we can really get a consistent set of estimates. A little of a lot of people’s time can make this happen. The Chinese proverb ‘many hands make light work’ is a unique strength of Cyclone Center.

Questions include whether the storm is getting more or less intense compared to an image from earlier in the storm lifecycle.Questions include whether the storm is getting more or less intense compared to an image from earlier in the storm lifecycle.



Participation is rewarding, its educational, and you will own a slice of the resulting Cyclone Center analysis. Indeed, several citizen scientist classifiers were co-authors on the paper. So, come click on Cyclone Center and get classifying!

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