The caterpillar was climbing up the twig that protruded from the trunk of the Flamboyant tree, almost to the wall of Alexander’s hut, munching the edges of the sweet leaves as it went. It ate continuously, only stopping when it got too dark to see the leaf. Dawn saw it start eating again. It rained, the caterpillar didn’t stop eating. The wind blew, the caterpillar didn’t stop eating. The sun shone, making the middle of the day very hot until the leaves started to wilt but still the caterpillar carried on eating.
It didn’t stop eating until,one day, it felt a different urge come upon it. It stopped eating. It extruded a thread and then dangled from the twig. It dangled, dangled and waited as its body absorbed the nutrients from all those leaves and, as it did, it slowly changed form inside its protective case.
*
Andrew Higginson was a meteorologist at the Woods Hole Marine Oceanographic Institute on Cape Cod. Today was a big day for him. A tropical storm had been forming for several days in the Caribbean and today there was a meeting of the specialists, with Andrew in the chair, in room 115C to discuss the issue and the storm prognosis.
Andrew had worn a suit and tie as he was the chairman but the other six men were dressed in ‘student shabby’ with overtones of ‘tropical indolence.’ This meant that they all wore sandals or flip flops, surfers shorts and Tee shirts. A couple went even further and had the 70’s haircut, which meant a pigtail. ‘A right bunch of scruffy pirates,’ thought Andrew. They certainly didn’t look like dedicated scientists at the top of their field, as they unarguably were.
The exception was the smartly dressed woman sitting at the end of the tale. She wore a black, all-encompassing dress with vivid red geometric patterns embossed on it, all topped off by a long, flowing golden scarf. No one knew who she was and why she was here. She was Dr Constanza Grant-Price, ‘Connie’ to her friends. She said nothing, but listened intently to what the others reported and jotted neat notes on her A4 pad with a 0.5 mm fine-point drawing pen.
It was the 15th August, right in the middle of the North Atlantic hurricane season so a rapidly forming tropical cyclone was not unexpected, but this one seemed to be getting larger than normal but still didn’t seem to be building with the usual speed.
Once they were all seated, the coffee machine severely depleted, Andrew stood up and pointed to the first Keynote slide showing on the screen, shone from the projector mounted in the ceiling.
‘This satellite picture shows tropical storm “Ira”. You can see the anticlockwise swirl and the size across the centre. It is a larger than average storm and its parameter ratio is within normal limits but there is one strange thing in its development.
As you know, these storms normally follow a similar pattern even though they vary in the quantity of entrained energy so they grow at a daily, known, rate. This one is different however. “Ira” is growing more slowly than normal and the rate of change is slowing down. If this rate continues on its present path, it will stop growing in six days time.
I’ll now go around the table asking each of you to give your view of your own specialist area as it relates to this incipient . After we have all the data from each of you, I will open and chair a free discussion to try and get to the bottom of this.
Shall we start with you Tom? ‘
‘OK. As you know, my speciality is ocean water temperature. Our measurements show that the upper 50 metres of the ocean under the developing cyclone is, at 28oC, well above the cyclone genesis minimum of 26.5oC. This means that, from my point of view, the cyclone should be developing, driven by the energy it is gaining from the warm ocean,’
‘Thank you, Tom. You next David.’
‘Using the Emmanuel model of Maximum Potential Intensity I have found that the limit of intensity, using the ocean temperatures that Tom has given me, is very high so we potentially have here a very intense storm - “Ira” should be a big one! If it slowing down and appears to be heading for a zero-growth stasis, then that is very strange and outside of our normal parameters.’
‘OK, thanks David, do you have any ideas James?’
‘Well, err, as you all know, I deal with the Coriolis force and its effect on the tropical cyclogenesis. In this case, the storm centre or the surface expression of the storm centre - the epi centre if you will - is about 1900 km North of the equator. This easily meets the need for the epicentre to be at least 500 km from the equator to allow tropical cyclogenesis, so there is nothing unusual there - in my field anyway.’
‘Thanks for that contribution James.’ said Andrew. ‘Have you managed to identify the low level disturbance that set ‘Ira” off in the first place, Paul?’
‘There is nothing of note, Andrew, so we have to assume as usual that it was the depression last week in the ITC.’
‘In English, please Paul.
‘Oh, sorry - ITC is just a TLA ( three letter abbreviation ). It means Intertropical convergence zone.’
‘Now we come to the vertical wind shear. Anything unusual that you have seen recently? Viv?’
‘No, the vertical wind shear has been fairly weak over the last couple of weeks between the tropopause and the ocean surface so ‘Ira” should have been free to develop massively upwards.’Just the normal temperatures and pressures, I’m afraid, nothing unusual.’
‘Well Graham, we are all relying on you to come up with something surprising, you are least representative of the six parameters required for a tropical cyclone generation. What have you got for us?’
‘At first I thought it must be the upper level jet stream that was slowing down the storm’s development but that was normal for this time of year. I then checked the data for weaker wind speeds and higher minimum pressures - a baroclinic initiation, we call it. That was also normal.So I have to tell you that there is no favourable trough interaction that I could see.’
Andrew stood up and used his laser pointer to set a red dot on the screen. He highlighted the six parameters in turn and checked each one of as being within the normal range and so could not account for the slow and about to stop, development of the storm. The six specialist storm scientists started volubly defending their positions, each saying that one of the others must have got their data wrong, each defended their own numbers until there was quite a hubbub in the room and there was no resolution in sight.
The meeting wasn’t coming up with any solutions so he decided to close it and regroup at 1000 the following morning. ‘Have a think about it overnight and hopefully we will come to a conclusion tomorrow’ he half shouted at their departing backs. ‘Will you be here tomorrow Connie? he asked.
‘Yes, of course, I am just as puzzled as anyone but I am sure we will get it sorted out tomorrow.’
*
The dangle was coming to an end, there was movement inside the case. The case split at the bottom, the end furthest from the thread that was supporting it from the branch of the flamboyant tree. The tree had stood for many years on the headland overlooking Nelson’s Dockyard in Antigua.
The caterpillar wasn’t interested in the history of the place. In fact the caterpillar had disappeared. It had metamorphosed into a different creature, one that was slowly easing itself moistly from the confines of its home. It managed to emerge fully and then carefully stretched out its long, weak legs. It stood there for some moments still folded up, as it had been made. Eventually the creature realised that it had wings and experienced an irresistible desire to stretch them out. It slowly and carefully did so. Its wings were revealed in all their black, gold and red glory, vivid patterns embossed on them. The creature waited, the wings drying and stiffening in the tropical sun.
After five short minutes the wings were dry and ready to use. The creature knew the time had come but was not aware of the consequences so it gave into its need. It jumped into the warm, gentle breeze. The butterfly flapped its wings and fluttered by the flamboyant tree that was its birthplace. It now had to search for a mate among the myriad others from the same tree, family tree, and lay the eggs that would be the start of the next cycle, the next generation.
*
It was five minutes past ten the next morning. All were there in the meeting room except Connie.
Andrew said,’Does anyone have any suggestions as to why ‘Ira’s” development is so slow and looks like it will not develop into a full cyclone?’
‘I do,’ said a voice from the opening door. ‘I have just come from the zoo physics department and we are fairly sure we have got the answer.’ Constanza walked to her seat at her accustomed place at the end of the table and sat down, arranging her notes neatly on the table in front of her.
Seven pairs of eyes followed her progress, all agog to see what she had found that they couldn’t unearth from all their data.
‘If I may explain Andrew?’ He just nodded, impatient to hear the denouement of the mystery.
‘You probably don't know either me or my department. My speciality is chaos theory as it applies to the living world. I study things like shoals of fish and flocks of birds and how they manage to fly or swim as a coherent swarm or shoal with no communication between the individuals.
I had a hunch last evening so I telephoned my colleague who is doing some field research on cyclical metamorphism, especially as it applies to butterflies on Antigua. He told me that the 13 year cycle butterflies were all emerging from their cases over the last few days. Their wing flapping has resulted in the effect, predicted by chaos theory, that it would have on the weather. They only live for three days, just long enough to mate and lay their eggs so I predict that ‘Ira’ will resume its development tomorrow and turn into a large tropical cyclone.’
The windows rattled in the increasing wind as Connie gathered up her notes and fluttered out of the room, leaving behind seven incredulous - and seriously miffed - meteorologists.
