The Destruction of Kirk

Tropical Storm Kirk would normally be a good candidate this time of year to intensify into a hurricane and threaten the Caribbean, Mexico, and the United States.  However, this morning’s Infrared satellite loop shows a storm on the verge of dying:

Here, the colors indicate cold clouds (convection) and the light gray colors indicate warm, low-level clouds.  Notice the rotating feature of low clouds near the middle of the image emerging from the convection and moving toward the west-northwest – that’s the low-level center of Kirk.

This is what is called a “sheared” tropical cyclone.  The upper level winds in this area are blowing from a different direction and at a much higher velocity than the winds near the surface.  This situation has effectively chopped the storm up vertically.  This is bad for tropical cyclones because the energy that they need to survive is released in the giant convective clouds (thunderstorms).  If this energy is displaced away from the circulation center, the storm will weaken.  Kirk is about to become an ordinary open wave.

Sheared tropical cyclones are not always easy to see on satellite imagery.  Here are a couple of other pages you can look through to see other examples and learn how to classify them on Cyclone Center:

Joaquin: Classifying Shear Storms in Cyclone Center

Examples of typical scene types

-Chris

– Chris Hennon is part of the Cyclone Center Science Team and Professor of Atmospheric Sciences at the University of North Carolina at Asheville

Welcome New Tropical Cyclone Classifiers!

Maybe you are here from a Zooniverse email, or maybe you found us some other way.  Thanks for stopping by and helping us do science!  Here’s some quick tips and advice to help you get comfortable classifying cyclones.

1. Do the tutorial and use the field guide.  Our project can be a little more overwhelming than some others because it is sometimes hard to know what to choose.  Each question has “help” close by – just scroll down to find it!
2. Don’t be afraid to be wrong.  Early on you might be worried that you will choose the wrong picture and screw up the science.  It’s fine!  You are one of many people looking at an image and we’ll account for choices that might not be the best.  It’s how crowd sourcing works.
3. Ask questions in “Talk”.  Use the forum to communicate with us and ask us questions about storms that you are classifying.  We’ll get back to you usually very quickly but always within a day or two.  We like to hear from our classifiers!
4. Know that every classification you do is helping us.  EVERY click is important!  As you complete more images your responses will become even more valuable as you gain experience.  We have a lot to do and we appreciate your contributions.

That will get you started and hopefully keep you going.  Again, please don’t hesitate to contact us with your questions or advice on particular images and patterns.  Thanks for participating!

-Chris

Timeline: How we got here …

How an idea became a dataset, which led to a citizen science project.

The road to this point – having nearly 300,000 image being analyzed by hundreds of helpers – was a long one. This was not foreseen when it all began.

Your Classifications Are Making A Difference

Cyclone Center was the 14th project hosted by Zooniverse when it was launched in September of 2012 and only the second that was based on weather or climate data.  As we come up on our 4th birthday, we’d like share what we’ve learned so far and how your classifications over the next few months will lead to even more exciting findings.

Typhoon Nabi (2005) was a powerful storm that our classifiers successfully completed analyzing.

The reason for Cyclone Center is simple.  Tropical cyclones generally develop over remote areas of the ocean, where there are few if any direct observations of them.  It is vitally important that we know how strong these storms are for societal (e.g. warnings, evacuations, protecting life and property) as well as scientific (e.g. are storms getting stronger with climate change?) reasons.  Since storms are typically not directly measured, scientists use images of them to estimate the wind speed.  Unfortunately, although the algorithm used around the world is basically the same, it is subjective and significant disagreement has crept into the historical record.  Cyclone Center uses a special set of satellite images and classifications from you to determine a more consistent, and thus better, estimate of tropical cyclone winds.

Over the last four years, we have learned much and have had a number of notable accomplishments with your help:

Joaquin: Classifying Shear Storms in Cyclone Center

Tropical Storm Joaquin is moving slowly over warm North Atlantic waters this evening.  If atmospheric conditions were ideal, Joaquin would be well on his way to becoming a hurricane.  Instead, he is struggling to develop because the atmospheric winds are creating strong “shear” which displaces the energy source of the storm away from the center.  Watch the animated image below:

Participate in Real Science – Help Classify Tropical Cyclone Winds

Cyclone Center, now in its third year, is a website that allows citizen scientists like you to help meteorologists like us determine the maximum wind speed (or “intensity”) of historical global tropical cyclones.   We need your help to complete this ambitious project.

Why am I needed?

First,  there are way too many images (nearly 300,000!) for us to do it alone!  Second, your responses as a group are almost always just as good as an expert!  And third, there are disagreements in the historical record that must be addressed.    For instance, there are studies in published literature that suggest that typhoon activity is both increasing and decreasing in the western Pacific Ocean. Clearly both cannot be true!

Why are there questions about tropical cyclone data? 

Spawns of El Nino? Hurricanes Iselle and Julio Aim For Hawaii

Cyclone Center is tracking two storms as we classify this afternoon.

It has been quite a remarkable week in the eastern and central Pacific that has culminated in two hurricanes taking aim at the Hawaiian Islands today.  Hurricane Iselle has shown herself to be quite resilient as she has maintained her hurricane strength despite moving over cooler ocean waters.  Hurricane warnings are out for the big island as residents prepare for a significant event.  Meanwhile, Hurricane Julio is following close behind, continuing to intensify despite his movement over cooler waters.  The graphic below from the Central Pacific Hurricane Center shows the likelihood of significant winds over the next few days in the islands:

Kulab says “Please Classify Me!”

Not much has been happening in recent weeks in the tropics (with the notable exception of the extreme western Pacific), so allow me to try generate some fake excitement by highlighting one of our four featured storms – KULAB.  Why Kulab?  

A Quiet Hurricane Season in the Atlantic?

The official start of the hurricane season in the North Atlantic was June 1 and most experts are predicting a relatively quiet season, pointing to relatively cool water temperatures in place and a developing El Nino in the Pacific.   El Nino can be thought of as a substantial warming of ocean water in the central and/or eastern Pacific which in turn alters global weather patterns.  Atlantic hurricanes typically encounter more hostile atmospheric conditions during El Nino events, limiting their potential to develop and strengthen.  Most of the inactive seasons in the Atlantic over the past 20 years have occurred during El Nino events.

Featured Storm – Hurricane Emily (2005)

By the time Emily made her appearance in the second week of July, the 2005 Atlantic season had already produced four named storms (tropical storm strength or better) and was on its way to a record breaking performance.  So it was hard to stand out from the crowd that year, but Emily sure did.

Emily formed the way many of the strongest tropical cyclones do in the Atlantic – as a tropical “wave” or disturbance that left the coastline of Africa on July 6.  She struggled at first to get her act together, as dry air penetrated her core and the upper level winds in the area kept trying to rip her apart.  But Emily kept it together long enough to obtain tropical storm status on July 11.  But the fun was just beginning.

Hurricane Emily readies herself for the final plunge into Mexico

The next day, the “steering winds”, or the upper level winds in the atmosphere that push the system along, increased in intensity.  Emily’s forward speed increased from a sluggish 10 kt. to a quite respectable 17 kt.  Although this initially made Emily’s environment less favorable,  recon planes noticed her winds at the surface unexpectedly began to increase.  Everything seemed to fall into place and just 2 days later Emily was a major Category-4 hurricane with maximum winds near 115 kt.

As Emily passed south of Jamaica, the records began to fall.  She became the earliest (since records began in the 19th century)  tropical cyclone to reach Category-5 status.  Furthermore, Emily to this day is the only known storm to ever achieve Cat-5 intensity in the month of July in the Atlantic.

Fortunately, Emily spent most of her time over the ocean when she was strongest.   But she did pass directly over Grenada, Cozumel Mexico, and northeastern Mexico near San Fernando.  Damage was unexpectedly light in the Yucatan, with mostly minor wind damage and flooding reported.  Northern Mexico appeared to receive the worst of the storm, with 90,000 people driven from their homes and thousands of buildings destroyed.  Miraculously only 6 deaths were reported from the storm, 4 in Jamaica when a car was pushed over a cliff from flood waters.

Go to Cyclone Center today and start classifying Hurricane Emily.  She was truly a memorable one.  Much of the information given here and more can be found in the U.S. National Hurricane Center tropical cyclone report for Emily.

– Chris Hennon is part of the Cyclone Center Science Team and Associate Professor of Atmospheric Sciences at the University of North Carolina at Asheville