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

Coming Into Port

Sunday, August 4th, 2013

Research Vessel Thomas G. Thompson at sea. Credit: UW

The Tommy Thompson, as it’s affectionately known, is heading back to Newport, Oregon to get ready for the next and final leg of this summer’s construction project for the regional cabled observatory. If all goes as planned, by mid-August they’ll have installed all the observatory’s secondary subnets at the Axial volcano and tested the cables and instruments, including an HD video camera. But, as chief scientist John Delaney says, with oceangoing research, plans are just the starting point. Weather, equipment failures, and occasional human error all factor into a continually evolving set of activities, more like jazz improvisation than a symphony orchestra.

This leg started with some setbacks, from a lost day at port fixing an electrical problem with the ship’s thrusters to being blown out on the first dive by ocean swells at the continental Slope Base. Once we got to Axial though, the team got into a rhythm of laying and testing cable, installing instruments and collecting data, the latter of which provided perhaps the expedition’s most joyous moment when two seismometers detected and recorded an earthquake. On the same 36-hour epic dive, however, we all learned a new term, “hockle.” A hockle is a kink in the electro-optical cable and a few of them were discovered in a cable, which testing showed had restricted its ability to carry data and power. The engineers will do more testing on the next leg and may need to replace some of the damaged cable. Despite those hiccups, the observatory construction work ended on a high note with a successful cable lay at Slope Base where the sea was almost glassy compared to earlier in the expedition. Throughout the cruise, the deck of the R/V Thompson was cleared of bright orange cable as ROPOS reeled out a total of 16 km on the ocean floor.

Over the last two weeks, the scientists also tried out new instruments including a temperature and salinity probe placed right into an extremely hot hydrothermal vent and a bottom-pressure tilt meter that will measure the movement of magma under the volcano. Co-chief scientist Giora Proskurowski deployed a reinforced collection bottle that can bring up a high-pressure gas sample from a hydrothermal vent for testing in the ship. It was exciting to look over Giora’s shoulder until the moment when he released some of the vent’s sulfurous gas, which immediately filled the room with the stench of rotten eggs. He calls it the smell of success, but I beat a hasty retreat.

The expedition was ahead of schedule going into yesterday, so the team was able to do an oceanographic favor for some colleagues in need (on the order of, “since you’re in the neighborhood…”). John Delaney was asked by geologists at Woods Hole Oceanographic Institute (WHOI) to recover a couple of seismometers that didn’t answer to pings and rise to the surface when signaled. (Underwater instruments commonly have an electronic recovery system that, when activated by a ship signal, engage flotation devices. These two prodigal seismometers, placed in different locations, didn’t come home when called). So we set off to the south on a search and rescue mission to find a couple of lost yellow boxes on the bottom of the ocean.

The dive planners didn’t know exactly where the boxes landed so they devised an ROV search pattern that started close to the sites where each seismometer was dropped. It proved unnecessary with the first yellow box, because ROPOS landed almost on top it and clamped on within five minutes of reaching the bottom. The second seismometer proved more difficult. We steamed to the spot described by the WHOI scientists, but the location had brisk winds and a strong current that made it very difficult for the ship to remain on station above the ROV. After one attempt and some waiting, John Delaney decided it served nobody’s interest to jeopardize ROPOS so we gave up on the second seismometer and started our 15-hour steam back to Newport.

Spending two weeks at sea on a history-making project, which this real-time ocean observatory will surely prove to be, is an incredibly immersive, exhausting and exhilarating experience. Part of my job here was to share the experience and the science I was learning along the way. We did some live ship-to-shore programs with audiences at the Exploratorium, experimenting with ways to activate an exhibit space with a distant research project. In the long term, we hope to find ways to connect the Exploratorium’s Bay Observatory, with its own complement of real-time oceanic and atmospheric sensors, to the regional cabled observatory in ways that would let people explore the data, ask questions and find connections between the deep sea and coastal locations.

Under the Sea, Down in the Muck

Saturday, August 3rd, 2013
Whales off coast of Oregon

credit: Mary Miller

One of the ship activities I enjoy most is watching the ROV ROPOS descend through the water column so I can do some wildlife viewing along the way. Of course, you don’t need an ROV to observe animals at sea. We’ve been seeing plenty of albatross throughout this expedition and have been visited by whales the last couple of days once we moved closer to shore.

But the creatures you glimpse as you descend to the deep are rarely, if ever, seen near the surface and many are adapted to life in the cold and dark. They often have large eyes and languid locomotion as befits an environment that has scarce resources, light and activity.

The first 200 meters or so is the photic zone, the region of the ocean where light penetrates and photosynthesis dominates the food chain. Jellyfish are often spotted here and the water can appear cloudy and full of white flakes and jelly-like particles, commonly known as “marine snow.” I was lucky enough to study at UC Santa Cruz with Mary Silver, a plankton specialist who was a pioneer in the study of marine snow. Before she focused on it, most marine biologists considered the non-living flocculant material an annoyance that clouded the ocean and fouled their net samples. But in the 1970s, Mary started sampling marine snow and discovering the true nature of this material. What she found was a complex stew of discarded larvacean houses*, dead organic material, and the general debris and detritus of the marine ecosystem, much of it teeming with bacteria and other single-cell organisms… in other words a potential food source for larger animals. By nibbling on marine snow, fish and other grazers can receive a nutritious meal that would otherwise be too diffuse and small for them to consume directly.  Eventually this organic-rich material sinks to the sea floor to be picked over by the resourceful bottom creatures we’ll soon see when ROPOS arrives there.

Nudibranch swimming through the water columnAs we descend beyond the sunlit surface waters, the cameras and lights on ROPOS let us peer into this little-known realm. A nudibranch undulates like a synchronized swimmer past the camera and then we spy one of our distant relatives, a solitary salp. A model of ocean efficiency, the salp looks like a jellyfish but it’s actually more closely related to humans and other vertebrates. It moves by pumping water through its body, filtering the seawater and extracting a meal at the same time.

After 90 minutes or so of descent, we reach the bottom with its compliment of crawling, swimming and sedentary creatures. The fish known as rattail dominates the swimming creatures while brittle stars–mobile, long-legged scavengers–populate the mud and rock bottom. Spider crabs are also frequent visitors. Attracted by vibrations, they come around to investigate ROPOS and the equipment surrounding it.

But my absolute favorite is the octopus. This is the intelligentsia of invertebrates, with complex eyes, large brains and fast reflexes.  They don’t seem disturbed by the invasion of lights and equipment of the ocean observatory, some will even act as ad-hoc inspectors of the cables.  I never get tired of watching their antics, whether it’s the Graneledone pacifica crawling with nimble arms across the bottom or the aptly named Dumbo octopus we see swimming in the water column as ROPOS makes it way back up the ship.

*Larvaceans, small tadpole-like invertebrates, build elaborate mucus houses and pump water through filters to collect plankton and bacteria for food. When the house gets mucked up, the larvacean discards it and builds another.

Underwater Photos Credit: OOI-NSF/UW/CSSF

One Small Quake for Axial, One Giant Leap for the Ocean Observatory

Saturday, July 27th, 2013

ROPOS control room where the ROV is piloted and controlled

Here’s the current dive plan:  Go to the sea floor, deploy and connect instruments, collect some data, return to ship. Sounds straightforward, but this is a scheduled 32-hour dive and the devil is in the details and the unexpected events. Routine as it can sometimes seem to me watching the unflappable ROPOS operators, meticulous engineers and calm scientists in the ROPOS control room, the team is dealing with continually changing conditions, equipment issues, opportunities, and problems.

For one thing, the weather picked up yesterday and the ship started rocking and rolling, so they cut the last dive short and put off an instrument survey for the next dive. The team wanted to get ROPOS up quickly so they could turn around and dive again with a basket full of instruments that will help complete the subnet at Axial seamount.

ROPOS launches are tricky with ocean swells

With waves increasing to about 2 meters (6 feet) the launch crane operator waited for a swell to pass and eased ROPOS into the water and on its way down before the next surge pulled down on the wire holding the ROV. Ninety minutes later, ROPOS was on the bottom, setting down the instrument basket and getting to work. Even removing instruments from the basket is a well-choreographed series of events, I’ve heard it described here as a ballet. It’s a ballet with four principal dancers: an ROV driver, two men each operating a robotic arm, and the vehicle itself. This team is so skilled and their moves so well-rehearsed, they often don’t even speak to each other as one robotic arm clamps on the basket, the other lifts out an instrument and ROPOS floats up and across the sea floor to find the precise location to deploy the seismometer. Setting the instrument platform down on a flat patch of lava, a robotic arm turns four screws in succession to level the instrument (the difference between this piece of construction equipment and the bubble level familiar to carpenters is the deep sea levelers use a marble rather than a bubble to find the center point). Only when it’s settled and level will ROPOS connect the instrument to the cable, awaiting the flow of electrons from the ship to awaken the instruments.

On this dive, the team deployed two seismometers and one “tiltometer,” more properly known as the bottom pressure tilt meter. This instrumentROPOS connected cable to the Axial subnetwas developed by Bill Chadwick at NOAA’s Pacific Marine Environmental Laboratory to record the expansion and contraction of the volcano from the flow of magma below. Bill was a scientist-in-residence at the Exploratorium last year and he’s been studying the Axial volcano for two decades. He was on the ship in spirit and on the phone last night as the ROPOS team eased his instrument in place. It’s painstaking work and you can sometimes see the scientists and engineers squirm in their seats, wanting to reach out and help ROPOS complete this delicate task. But their instruments are in good hands, these Canadians know their ROV and they finished the task ahead of schedule.

Then it was time for the engineers to flip a switch (actually click on a computer screen) and activate the cable network that powers the instruments and carries data back through ROPOS to the ship. The plan was to collect data for six hours to make sure the instruments were working and the subnet infrastructure was ready to be plugged into the primary network that connects to the shore station and the Internet when the observatory goes live next year.

First in-situ earthquake recorded in real-time at Axial Volcano.

Once all the equipment was turned on and systems verified, the team in the ROPOS control room settled in to wait for data. For those awake at 4:30 AM, they didn’t have to wait long. Within 15 minutes, there was a tremor on Axial, picked up by one seismometer, then the other in quick succession. It was a nice moment for the night owls working on the R/V Thompson and for those of us who woke up to a beautiful data graph the next morning.

As the Spool Turns

Wednesday, July 24th, 2013

9 PM Aboard the Thomas G. Thompson

ROV ROPOS with cable spool attached Today, it was all about the cables that deliver power and data to the ocean observatory’s secondary nodes at the Axial volcano. As anyone with an old house knows, wiring can be a troublesome thing and you definitely don’t want to take any chances with it. Earlier this morning, the ROV ROPOS attached a large spool of bright orange cable to its belly and set out to descend almost a mile to the sea floor to connect to the equipment waiting on the bottom and lay the cable. As I watched from the back of the ROPOS control room, the shift supervisor asked to zoom the camera in on the cable loops for a closer look. He didn’t like what he saw. The normally plump, round “oily” cable was flattened, indicating that it might be leaking oil and exposing the wiring inside to the corrosive seawater outside. Rather than take a chance that it would fail in the future, the team of scientists and engineers onboard decided to bring the spool back up for a closer look and some testing of the cable.

A major activity of Visions 13 expedition this summer is to lay extension cables for the Regional Scale Network of the Ocean Observatories Initiative. In total, this network of instruments, cameras, and interactive experiments will be connected to shore by 900 km (560 miles) of backbone cable. This is no ordinary cable: it can carry up to 200 kilowatts of power and up to 240 gigabits of data a second. It’s rugged as well, built to endure a long trip to the seafloor where it’s exposed to corrosive seawater and pressures up to 4000 pounds per square inch. This is the true infrastructure that will make interactive, 24/7 oceanography possible. To be sure, the instruments that plug into it are state-of-the art. But as chief scientist John Delaney says, the young scientists of today will dream up new instruments and experiments in the future and that infrastructure will be there for the 30-year lifetime of the cabled observatory.

Laying cable on the ocean floor has a long and storied history, beginning in 1850 with a telegraph cable between England and France. The first audacious attempt to wire Europe and North America with a trans-Atlantic communications cable was dreamt up by Massachusetts paper magnate Cyrus W. Field. In 1857, 2,500 miles of cable was coiled into drums and loaded aboard two sailing vessels each loaded with 1500 tons weight. The heavy cable kept breaking on route, even as engineers tried repairing it as was being spooled across the ship deck. But after much frustration, they finally succeeded in joining the two continents and the first telegraph was sent from Queen Victoria to President James Buchanan on August 16, 1858.  Alas, the cable began degrading and the connection only lasted for two weeks. It took another eight years before the next, more successful cable was laid and it persisted.

Co-chief scientist Giora Proskurowski checks the oil recovered from cable.

For today, the cable coiled on the Thompson’s deck will no doubt fair much better than Cyrus Field’s first submarine telegraph cable. The return trip to the surface proved that the oily cable didn’t contain as much oil as it should so the engineers drained it and will perform pressure testing later to make sure there are no leaks. If it holds, they plan to refill it with a special silicon oil, seal the cable ends and return it again to the sea floor to connect it to a seismometer that will rest on the Axial seamount until the next volcano. Cyrus Field would be proud.

Waiting for the (not terribly) Big One

Monday, July 22nd, 2013

Aboard the R/V Thomas G. Thompson, 2 PM

Axial Seamount node, courtesy of Univ. of Washington

We’re spending a few days at the Axial Caldera, laying cable that will eventually connect instruments, sensors and HD cameras to the entire regional network to study and interact with this underwater volcano in real time. Axial Seamount is a great study site because it’s an active volcano (albeit not nearly as explosive as Mount St. Helens was in 1980) . From recent events scientists think it erupts about every 10-12 years. In fact, right now ROPOS is laying cable directly over fresh lava from an eruption in 2011.

The regional cabled observatory  component of the National Science Foundation’s Ocean Observatories Initiative will instrument and wire the volcano so that the next eruption can be studied in real time from beginning to end. Chief scientist, John Delaney, says this is valuable both to investigate the underlying mechanisms and geology of submarine vulcanism, whose eruptions can trigger tsunamis, but also measure the gases, heat and fluids that flow from beneath the sea floor and contribute to living communities in the deep sea (more on the chemistry and biology of these systems in later posts).

Axial Seamount is part of a chain of underwater volcanoes that dot the length of the spreading zone where the Juan de Fuca tectonic plate pulls away from the Pacific plate. The earth’s crust is thinner along these undersea volcanic ridges, which means it doesn’t take as much pressure for the magma below to erupt through the surface and start flowing. [The Hawaiian Islands are also a chain of volcanoes so productive that they’ve now become aerial volcanoes. The Big Island of Hawaii is the youngest in the chain and growing all the time from the eruptions of the Kilauea volcano. The next in line, Loihi Seamount, is about 1000 meters below the surface just off the Big Island.]

More than 60% of the planet’s vulcanism happens underwater but that has been difficult to study up to now because, well, itEruptive blast, courtesy of NSF and NOAA happens underwater.  In 2009, during an expedition sponsored by NOAA and NSF, scientists filmed an active eruption during an ROV dive in the Lau Basin in the Eastern Pacific, complete with sound, but they couldn’t stay long. When completed, the cabled observatory will have eyes, ears and sensors on the Axial Volcano to capture its every burp and lava flow with instruments that include a tripod-mounted bottom tilt and pressure instrument that will measure the inflation and deflation of the seafloor (an indication of magma rising up), a titanium-encased broadband seismometer and low-frequency hydrophone to detect earthquakes in real time, and HD video and still cameras to capture the live action of events on the sea floor. These instruments will help scientists better understand when and how volcanoes erupt and the ways they contribute to the biology, chemistry and overall geology of the ocean.

History on the High Sea

Sunday, July 21st, 2013

1 PM aboard the Thomas G Thompson

ROPOS being lifted back onboard TGT

History is being made on the Visions 13 expedition, but it sometimes comes in fits and starts. We’ve been holding here on the edge of the continental shelf 3000 meters (6000 feet) below us waiting to launch the ROV ROPOS. The crew first tried this morning around 6 AM, with the aim of placing a one-ton “medium power junction box” on the study site known as Slope Base. Everything was going smoothly until the combined load of the ROV and junction box was being lowered into the water and a swell lifted the ship, pulling the ROV load down relative to the ship and straining the cable. Called a “snap-load” this isn’t safe for the ROV or the junction box, so the crane operator lifted the ROV safely back onto the ship’s deck to wait for the weather to cooperate or come back another day.

Such is the nature of ocean research. You never want to take unnecessary risk with equipment or crew so we wait until conditions improve or change the plan. In the meantime, back to history.

The chief scientist of the expedition, John Delaney, explained the reasoning for a cabled ocean observatory in a two-hour conversation he had with  graduate students yesterday. Here’s the condensed version (you can watch John’s Ted talk for a more complete version):

  • The oceans are the planet’s life support system
  • The oceans are complex and their geological, chemical and biological systems are little known
  • If you want to understand how the entire Earth system operates, you need to monitor the ocean with a seafloor observatory that operates continuously and share the data with everyone.

John also points out that the need to understand Earth’s complex and interacting systems is urgent. The oceans and the planet are undergoing rapid environmental change that will affect the lives of billions of Earth’s inhabitants. In order to adapt to and mitigate these changes, we need to understand why and how our life support system is changing and what the future might bring. That is why the National Science Foundation, and by extension all us taxpayers, are investing more than $385 million in funding the Ocean Observatories Initiative of which the Visions 13 expedition is a part.

Finding My Way on a Research Ship

Saturday, July 20th, 2013

Aboard the R/V Thompson, Newport Oregon

View of Yakuina Bridge

Taken from the bow of TGT looking out the harbor mouth

We’re about to head out to the jobsite of the world’s deepest construction site, about 300 miles off the coast of Oregon. Before we head out of Newport Oregon, a few engineering chores still need doing aboard the Thomas G. Thompson (aka TGT) a 274 foot research vessel operated by the University of Washington (UW or as the locals say “U-dub”). The ship was named after the chemist and oceanographer Thomas G. Thompson who devoted his career to the chemical study of seawater and founded the UW oceanography lab.

My task for the day is to settle in and figure out where things are on the ship so I don’t embarrass myself walking into someone’s sleeping quarters, wander into a restricted area or interrupt a private meeting. It requires that you think in 3D since ships are laid out by decks or levels with many passageways and cubbyholes that pretty much look the same. You move between levels via ladders (ship term, even though they more closely resemble stairs) that are in different parts of the ship so you have to think about which way to turn when you reach the level you think is your destination. Starting from the engine room in the bowels of the ship, there are seven levels to the top level where the wheelhouse (04 level) is located, from which the captain controls the ship. Moving down four levels from the wheel house (these decks have living quarters for the officers) is the very important 01 deck, also known as the Foc’sle deck, where the galley and mess hall are located, along with the lounge where you can read, watch movies or play board games. At meals, the whole ship comes together and you can find yourself chatting with a deck hand, a grad student or the chief scientist, learning something new with every knosh.

The deck below the Foc’sle is the main deck where the science labs, ROV control room and the computer lab are located. I have bench space in the computer lab where I have access to wifi and can watch the live monitors that show video from cameras on the ROV, the control room and the outside decks of the ship. I’m in here with a videographer, Ben Fundis, a UW science writer, Nancy Penrose, Giora Proskurowski, co-cheif scientist for this leg of the cruise, and Ed McNichol, a multi-talented connectivity, media production, and camera guru who makes sure the ship’s satellite connections, the multiple video cameras, and the data are all operating correctly so the science is being captured and the video streams and live shows are getting out to the Internet.

Sleeping quarters on TGT

I’m sleeping mid-ship on the deck below the main level in a two-bunk stateroom with Nancy as my roommate. We have a comfortable, spacious cabin, sharing a bathroom with two ladies on the other side. Mid-ship is a great location once we’re underway because it’s farther away from the noise of the huge diesel engines near the stern (back) or the waves crashing against the bow (front). There’s also less movement in the lower middle of the ship, so once we get under way (hopefully later this evening) it’ll be easier to sleep. I don’t anticipate any trouble sleeping, I love the movement of a ship at sea. As long as it’s not too rough, I feel like a baby in a cradle being rocked to sleep.

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.”