Archive for the ‘National Oceanic and Atmospheric Administration’ Category

Our carbon buoy gets a makeover

Saturday, July 26th, 2014
The NOAA CO2 buoy measures carbon content in the bay and atmosphere at Pier 15.

The NOAA CO2 buoy measures carbon content in the bay and atmosphere at Pier 15.

July 25, 2014

Since the Exploratorium opened at its waterfront location more than a year ago, we’ve been engaged in a unique experiment with the National Oceanic and Atmospheric Administration. NOAA’s  Pacific Marine Environmental Lab in Seattle lent us a beautiful ocean buoy, outfitted with instruments to measure carbon in the ocean and atmosphere. For the last 15 months, it’s been bobbing in all its white and red glory in the lagoon between Piers 15 and 17, occasionally surrounded by mist from the fog bridge art piece.

Instruments mounted on the buoy have been gathering oceanographic and atmospheric data to help scientists understand how the build-up of carbon dioxide in the atmosphere and ocean affect marine ecosystems. Ours is the only one of NOAA’s CO2 buoys so close to an urban center and a major estuary, both of which add carbon to the bay water. The unusual chemistry of San Francisco bay waters can be a living laboratory for the future, when marine environments become increasingly more acidic (more on that in a later post).

Operations chief Chuck Mignacco steadies the angry bathtub while Chris Raleigh looks on.

Operations chief Chuck Mignacco steadies the angry bathtub while Chris Raleigh looks on.

We’ve reached a milestone with the experiment, the first time we’ve pulled the buoy out of the water for maintenance. It’s a complex choreography of forklift, mobile crane and a balky metal watercraft dubbed “the angry bathtub” to lift the one ton buoy from the water onto our outdoor plaza. Over the next week, our marine technician, Chris Raleigh, will be swapping out and calibrating instruments, scaping off marine growth and repainting the faded red striping all in view of the public.

I was excited to get a look at what’s been growing below the buoy’s water line and woke early to get down to the Exploratorium and document this momentous occasion. As expected, the bottom of the buoy was covered in leafy green and lacy red algae, with some mussels,

After 15 months in the bay, the bottom of the buoy is covered with marine life.

After 15 months in the bay, the bottom of the buoy is covered with marine life.

bryozoans and limpets in between the plants. We even found a few oysters and a small scallop. The shells of the mussels and oysters were very fragile and broke apart in my fingers, quite unlike the thick-shelled tide pool mussels I’m used to handling. I wonder if this could this be from the higher acidity of the water or the fact that these shellfish are protected from wave action.

We even saw growth on the chain floats: solitary stalked tunicates attached along with the slimy colonial tunicates, mussels and osyters. Crawling all around were crabs, segmented worms (which resemble aquatic centipedes), ghost shrimp and some tiny iridescent shrimp of the brightest lime green I’ve ever seen. We took samples and plan to share them with scientists who study invasive and native organisms of the bay.

Just about any surface exposed to bay waters will be colonized with all manner of colorful invertebrates and algae.

Just about any surface exposed to bay waters will be colonized with all manner of colorful invertebrates and algae.

The buoy will be out of the water for a week, getting its yearly make-over before we lift it back into the bay to start collecting live data once more. In my next post, I’ll discuss what we’ve learned from the carbon and oceanographic data we’ve gathered over the last 15 months.

The Ocean’s Carbon Problem: Investigations in San Francisco Bay

Tuesday, September 10th, 2013

Right after we moved the Exploratorium to its new waterfront location, we got a gift from NOAA’s Pacific Marine Environmental Lab in Seattle: a beautiful red-and-white ocean buoy. Normally, these buoys are deployed out at sea to measure dissolved and atmospheric carbon dioxide, but we got to put one right in the lagoon between piers 15 and 17.

Accumulated CO2 in the Atmosphere and Ocean NOAA

Since the beginning of May, the buoy has been collecting CO2 data from the bay waters and the atmosphere in San Francisco and we’ve noticed some interesting patterns in the read-outs. First, it might help to know why we care about dissolved CO2. Carbon dioxide is constantly exchanged between air and water; when atmospheric CO2 levels increase, more of the gas is absorbed by ocean. The increase in dissolved CO2 is increasing the acidity of the ocean, an effect called ocean acidification. Since the start of the industrial age, the ocean has absorbed 30% of the CO2 produced by the burning of fossil fuels, changing the chemistry of the ocean. These chemical changes can have harmful effects on the biology of marine organisms that build shells, including oysters, plankton, and a marine snail called a pteropod, which in turn affect food webs and marine ecosystems.

We see higher levels of dissolved carbon dioxide in San Francisco Bay than offshore in part because urban areas are sources of atmospheric CO2 but also because our location is influenced by both the open ocean outside the Golden Gate and the freshwater estuary in the South Bay. Estuaries typically contain more dissolved CO2 because they have higher levels of organic matter than the open ocean. When organic matter decomposes, it releases CO2 into the water. At Pier 15, we see a decrease in the dissolved CO2 and sea surface temperature (SST) and an increase in salinity as the tide rises and brings in cold salty and less acidic water from the Pacific. As the tide falls, estuary waters flow in from the south bay and the CO2 levels go up, while temperature increases and the salinity goes down. That’s why you see this daily zig-zag in the data.

This shows the dissolved CO2 (above) and oxygen (below) from the buoy at Pier 15.

The data also shows a longer two-week pattern of decreased levels of dissolved CO2 corresponding to an increase in dissolved oxygen. We think the increased oxygen is from a bloom of phytoplankton which take up carbon dioxide (decreasing the dissolved CO2 levels) and release oxygen (increasing the O2 levels) as they grow. I heard from scientists at Bodega Marine lab that this bloom also corresponded to an upwelling event off the coast which brings cold, nutrient-rich waters from the deep up to the surface feeding the phytoplankton bloom. This is similar to what happens with atmospheric carbon dioxide in the summer. As plant life grows in the summer it absorbs CO2, causing a temporary dip in the levels of atmospheric carbon dioxide. In the winter, plants shed their leaves which decay and release CO2 into the atmosphere, creating a yearly zig-zag in the gas levels.

The CO2 buoy is part of our Wired Pier project which places scientific instruments and sensors in the water and on the roof of Pier 15. In the coming months we’ll post more of these data stories, but you can access the current real-time feeds and other locations at

Clouds from Both Sides

Monday, September 10th, 2012

Whenever possible, I try to book a window seat on plane flights and look at clouds. If I remember to take my camera out of the carry-on bag, I like to shoot pictures of the pretty or interesting clouds and share them with other cloud afficianadoes.

Boundary Layer Clouds

You can see the atmospheric boundary layer from a plane by looking for the flatish cloud tops.

Here’s a picture I took on a return flight from Colorado last week just as the sun was going down. When the tops of clouds form a fairly flat layer like this, it can indicate a demarcation in the atmosphere where conditions change from a turbulent air mass below the cloud tops where most of what we experience as weather oocurs to a more stable layer of the atmosphere. (The exception being really strong thunder-head clouds that punch through the others… when you see those anvil-shaped clouds from a plane, the pilot is usually trying to skirt around the often powerful storms below).

That transition point where clouds flatten out signifies the top of what’s technically known as the atmospheric boundary layer or planetary boundary layer. Generally about one or two kilometers thick, the boundary layer is affected by daytime heating and nighttime cooling, surface winds, fog and most clouds… in other words, weather.

Surprisingly the temperature above the boundary layer is generally warmer than the layer below. The way meteorologists traditionally measure the height of the boundary layer is by sending up weather balloons that continously measures temperature as they rise. When the temperature of air take a clear turn from gradual cooling towards warmth that signifies the top of the boundary layer. The National Weather Service for the Bay Area launches a weather balloon from the Oakland Airport twice a day to measure the height of the boundary layers and collect other atmospheric data for their forecasts.

As the Exploratorium prepares to move to the piers, we are making plans to install instruments and sensors that will monitor weather conditions, including an instrument to  measure the height of the boundary layer without having to launch balloons (although we’d love to also launch weather balloons!). Called a radiometer, it detects the temperature inversion through microwave radiation measurments. It’s one of the instruments that will make up our “Wired Pier,”  a set of sensors that will collect data about the Bay waters and atmosphere.

Rainy Day… Again?!?

Wednesday, June 1st, 2011

Mary arrives at ExploratoriumIt’s June 1 and I got thoroughly soaked on my bike ride into work today. By now in the San Francisco bay area, we’re usually into a spring pattern of mild, sunny days that have school kids and working adults thinking about playing hooky and heading for the beach. But for the last three months we’ve had what seems like relentless cold, rainy weather–more dead winter than a mere 20 days till official summer.

I gave our local National Weather Service meteorologist, Tom Evans, a call to ask him what’s up with the weather (all the while controlling the irrational desire to blame him for my miserable bike ride this morning). He confirmed that our weather, indeed, has been unusual with higher than normal rainfall, especially for a La Nina year. “We’ve been getting a lot of weather systems from the Northwest, picking up moisture from the tropics that’s giving us heavier rain periods than we usually see.”

Let’s back up a second and  talk about La Nina which I have some familiarity with from a webcast project I did years ago. Perhaps less well-know than it’s opposite twin El Nino, La Nina refers to cooler than normal water temperatures in the equatorial Pacific Ocean off the coast of South America. This cooler water disrupts normal climate patterns, with warmer, drier weather than normal in the Southwest and cooler, wetter weather in the Northwest. In the bay area,  climate patterns could go either way, but usually tends to the warmer, drier side. But not this year. Tom did a little study and found only three La Nina winters in the last 50 that  have been significantly wetter than normal in the bay area: 1955-56, 1973-74 and 2010-11. This year has been a real doozy. Our rainfall has continued into May (and now June) with an accumulated total in San Francisco  of over 30 inches or 175% of normal. We’ve had mountain snowfall at nearly twice the normal accumulation and it kept snowing in the Sierras, even into May when the annual Amgen Tour of California bike race had to cancel its first stage in Lake Tahoe because it *snowed* nearly a foot that day.

According to Tom and NOAA’s National Centers for Environmental Prediction (NCEP)  office, we are transitioning away from La Nina to a neutral ocean condition so maybe there’s a glimmer of hope that we’ll have some kind of spring… but not right away. On the NCEP website comes this ominous statement: “Atmospheric circulation anomalies associated with La Nina remain significant.” In plain English, Tom Evans says there’s nothing in the current condition of the atmosphere that will force a change in the jet stream. That means additional cool, rainy weather will be moving in as if on a conveyer belt over the next several days with another strong storm predicted for Friday. “The good news is that the Climate Prediction Center is telling us we should have a normal summer this year, but we have to get into a summer pattern  first… it might be awhile yet.”