The latest experiment in data visualization: small multiples, inspired by the Climate Lab Book. The full file is large enough for a poster, if you’re the kind of person who likes to have a quick visual overview of El Niño/La Niña events and long-term SST variability hanging in your office (I definitely am).
If you want a not-too-technical introduction to the current state of my research, check this out.
I made this poster for an event at Boston College tomorrow. The goal: introduce freshmen in an introductory climate class to an area of active climate research (and recruit interested students for our lab). I swapped the jargon/technical details for field photos. After all, scuba pictures capture students’ attention in a way no graph can!PDF research overview
Tropical cloud-watching never gets old. Near the equator, the warm ocean generates a ton of fuel for cloud growth. Over the course of a few hours, you can watch a small cloud grow into a tower tens of thousands of feet tall. If you look at satellite images of the Pacific, you’ll often see a band of these clouds just north of the Equator. That band is called the Intertropical Convergence Zone (ITCZ), which I’ve discussed before, and is the pillar of global atmospheric circulation.
The seasonal movement of the ITCZ over the Marshalls provides the country’s drinking water. Needless to say, it’s pretty important; when it’s too far from the Marshalls, wells and catchments run dry. However, it’s hard to simulate the ITCZ accurately in climate models, which makes its future behavior difficult to predict. As a first step, though, we can look at how its location and strength has changed in the past.
Unfortunately, I haven’t found many good visualizations of the ITCZ through time, so I made my own. This video shows monthly precipitation from 1979 through 2016, from NOAA’s Global Precipitation Climatology Project (GPCP).
Brief rant: Mapping the Pacific is hell. Most files and programs pretend that the world ends at the International Date Line, which runs smack-dab down the middle of the Pacific. So, when I tried to map the Pacific Islands, everything beyond the date line simply didn’t exist, and it took nearly a week to fix it. The result, though, is worth it, because I can finally generate plots that show the outlines of the oft-ignored Pacific Islands and reefs!
What climate patterns can we identify here?
In the past few weeks, I’ve been reading this book on climate change and tradition in the Marshall Islands, and it’s yielded some interesting quotes on how the Marshallese perceive sea level rise.
For example, when asked what would happen if the Marshall Islands are submerged, one resident had a simple solution:
It’s a funny answer, but it masks the nervous uncertainty that many Marshallese people share about their future. In the coming decades, the rate of sea level rise will depend on how aggressively we mitigate our carbon emissions, so estimates of future sea level rise can vary. Some Marshallese imagine a future in which the ocean engulfs the tops of their palm trees. That’s a bit extreme: most estimates put sea level rise between 0.6 and 1 meter by 2100.
These misconceptions led me to dig through the tide gauge records on Kwajalein Atoll, available here:
Some observations: 1) Sea level is rising. 2) There are sudden but temporary dips in sea level, in 1983 and 1997 for example. These drops in sea level match El Niño events. For the same reason, sea level dropped in 2015, but has since risen back up to pre-El Niño levels.
Sea level rise will continue to accelerate in the next century, reaching ~0.4 meters by 2100 (compared to 1986-2005) in the very best case, but more likely between 0.6 and 1 m.
Is that enough to put the Marshall Islands under water?
Even though the rate changes, sea level is clearly rising. It’s already about a foot higher than in 1880, and is expected to rise by up to a meter by the end of the century (if melting of polar ice sheets accelerates, this number could be much higher). This figure was inspired by Dr. Ed Hawkins’ now-famous climate spiral, and took advice from this talk on making beautiful figures.
Boston’s Long Wharf is flooding.
This flooding is part of a “king tide” – a tide higher than all others. When the sun, moon, and Earth are in alignment, and close to each other, the tides will have especially high amplitudes – that is, the highest high tides and the lowest low tides. If you want a general introduction to how tides work, check out this Crash Course Astronomy video.
So, with this week’s supermoon, the tides are especially strong – some of the strongest of the year. During high tide, salt water is sneaking through storm drains and spilling over seawalls all along our coasts.
This kind of flooding is often called “nuisance flooding” or “clear-day flooding” because it isn’t associated with storm surges or winds. But let’s be clear: this “nuisance flooding” is exactly how sea level rise works.
What’s more, these floods will become more common as sea level rises.
“Science and art belong to the whole world, and the barriers of nationality vanish before them.”
– Johann Wolfgang van Goethe, scientist, writer, & statesman
In the deserts of Arizona, I always talked about oceans the same way that we might talk about unicorns: It’d be nice to see one, but good luck with that.
Going to grad school in New England means I finally have an ocean within walking distance of my office. So, between SCUBA and oceanography courses, I’m taking every chance to learn more about the Atlantic.
Boston University has partnered with the Stellwagen Bank Marine Sanctuary to use the Research Vessel Auk to collect seawater and plankton data around the Sanctuary (a rectangular area stretching roughly from Cape Cod to Cape Ann). I know the phrase “collect data” can sound inherently boring, so here’s a whale picture to convince you that it’s actually fascinating:
On Tuesday, June 28, we surveyed sites along the southern coast of Arno. Apparently it’s a good place to spot marine life. Even though dolphins have been chasing our boat every day, Tuesday was truly exceptional. A pilot whale started following us, and I was able to snag some video (thanks to Diane for posting it!):
Diane and I went to the Marshall Islands with the goal of locating corals that would make good candidates for climate records. At Arno, this involved three dives per day for five days. That’s a lot of time underwater, especially since each dive was roughly an hour long. Though Diane was unfortunately unable to dive with us until the last day, I was lucky enough to dive with Kalena de Brum, who works for the Marshall Islands Marine Resources Authority, instead. She has a sharp eye for hidden wonders underwater!
Simon and Sara identify, measure, and photograph corals along a transect at each site. Kalena and I swim in the general area of each transect, scouting for corals. We’re looking for corals of the genus Porites, which you might know as lobe coral. The ideal Porites for sampling is a solid, tall mound, without any bore holes from clams or worms.
Good Porites, as it turns out, are really hard to find. When we spot one, I note its size, depth, and condition, and my dive buddy takes pictures.