NOAA Teacher at Sea
Aboard NOAA Ship Ka’imimoana
August 16-30, 2002
Day 11: August 21, 2002
I awoke and went out on the buoy deck this morning to find rain falling from overcast skies! Here are our observations at 0800 this morning:
Visibility: 12 nautical miles (nm)
Wind direction: 100° (direction from which the wind is blowing)
Wind speed: 15 kts
Sea wave height: 4-5′
Swell wave height: 5-7′
Sea water temperature: 27.4°C
Sea level pressure: 1012.2 mb
Dry bulb temperature: 25.0°C
Wet bulb temperature: 24.0°C
Cloud cover: 8/8, rain from altostratus clouds
If you’ve been mapping out our course on a “chart” of the Pacific Ocean (as I’m sure you all are!), you may have noticed that we’ve made a sudden shift to the south! Why? To divert away from a tropical depression forming to our east! The Commanding Officer, CDR Mark Ablondi, made the decision late last night, after French class, to reverse the order of our trip. Instead of visiting the buoys from north to south along 125°W and then cruising west toward the 140°W line, we’ll first head south along the 140°W meridian and then toward 125°W. Flexibility is key to the success of the trip, especially when considering the safety of the crew. A tropical wave is heading our way with a tropical depression behind it. To our north there are a series of subtropical high pressure cells which will cause the tropical depression to slide due west, very close to our original path, thus the reason for the change. We’re hoping to avoid all signs of the storm. However, we currently have overcast skies and rain falling from beautiful altostratus clouds. The only thing constant about the weather is change – gotta love it!
Our most exciting part of the morning so far has been a live test broadcast with Jennifer Hammond at NOAA’s Silver Spring office and others who will enable a future broadcast to come live to you. We had to attempt it three times because we kept getting disconnected. Larry, our very important computer technician on board, is looking into the cause of the problem. We’ll try another live broadcast test tomorrow morning before our first general broadcast, hopefully later this week (stay tuned on the web site for further information).
The constructed buoy that was going to replace the one to be removed at 8°N, 125°W, will now be used for the 2°N, 140°W replacement. Because ocean currents are much stronger near the equator, the buoys require more flotation. This means that two extra fiberglass inserts are placed inside the buoy (sort of like adding the donut hole to the donut). This will enable the buoy to float more effectively.
We tested the CTD profiler early this afternoon. CTD stands for conductivity, temperature, and depth. This instrument continuously records data as it is lowered through the water column to nearly the bottom of the ocean. It also collects water samples at preselected depths. Water is then brought to the surface from these depths and analyzed for salt and nutrient content. I have been asked to take some of the CTD measurements since we’ll be doing them a few times every day and I’m told it takes 1-2 hours. I’m very interested to see what it entails. I think that Jason will train four of us tomorrow.
Well, I reread my logs and decided that I need to provide some context as to why we’re all on the Ka’imimoana in the first place. El Niño! You’ve all heard the term, I’m sure, but what does it mean, and should it concern us?
Here is the story…
El Niño, Spanish for “the boy” or “the Christ Child”, is a phenomenon that refers to a warm ocean current that typically occurs around December (Christmas-time) off the west coast of Peru and lasts for many months. This appears to be related to a warming of the entire tropical Pacific Ocean.
Let’s go back even further… Under normal ocean and atmosphere conditions (during non-El Niño years), the trade winds in the Pacific blow from east to west across the tropical Pacific Ocean, dragging the ocean water beneath with them (due to friction). Because the water is being moved toward the western Pacific, it piles up such that the actual surface of the water near Indonesia can be up to approximately ½ meter (~1.5′) higher than off the west coast of South America – amazing! The sea surface temperature near Indonesia is also about 8°C (how many °F?) warmer than near South America because it has been warmed by the sun as it crossed the Pacific near the equator. Near South America, cold subsurface water then emerges at the ocean surface to take the place of the water that moved westward. This process is known as “upwelling” and brings cold, nutrient-rich water to the surface, which is attractive to many fish species, including the anchovy.
Warm ocean water is important for many reasons, primarily because it has a direct relationship with the atmosphere above it. Above warm water, evaporation increases, winds at the surface flow together, and clouds form. Thunderstorms form much more easily under these conditions causing rain. Heat is transferred from the ocean to the atmosphere in this process, known as “convection”. This shows why there is such a direct and important link between the ocean’s temperature and the winds in the atmosphere. Convection usually occurs over the warmest water and winds blow toward the warm rising air from all directions. Energy is transferred and this is one of the important flows across earth. I always tell my students that the earth constantly tries to maintain a balance and this is why there is movement. Earth is dissatisfied with excess heat near the equator and cold air hovering around the poles. In a move toward equilibrium, the wind flows and the ocean currents move…energy is being transferred! Okay, I could go on for days about this because I love it so much. Let’s move on to El Niño. During El Niño events, which typically occurred every 3-7 years in the past, but may be happening more often now, large-scale winds that normally blow from east to west across the Pacific Ocean diminish, and occasionally even reverse direction. Now, the warm water that is typically found in the western Pacific moves toward the eastern Pacific and, voila!, little upwelling occurs along the coast of South America resulting in fewer nutrients for the phytoplankton and other marine life that survive on the nutrients brought from below. With warmer water in the eastern Pacific, the process of convection shifts eastward with the warm water so the rising air and ensuing storms are found closer to the central Pacific.
Why is this important? El Niño results in changes to temperature and rainfall on a GLOBAL basis. For instance, because convection shifts eastward, parts of northeastern Australia often experience a major drought while the coast of Chile can receive severe floods. The 1997 El Niño event, one of the strongest ever experienced and recorded, resulted in heavy rains over the southern U.S., record rains in California, and a mild winter in the mid-western states of the U.S. At times, the monsoon that affects Southeast Asia arrives much later than normal. We are on the Ka’imimoana to help predict upcoming El Niño events . This is done with the help of 70 buoys that are located on the tropical ocean surface between 8°N and 8°S latitude. Sensors on these buoys measure atmospheric conditions like wind speed, wind direction, air temperature, relative humidity, radiation, and ocean temperature data from the surface to 500 meters below, to help determine if an El Niño event is occurring, or not. We do know that an El Niño is currently forming in the Pacific. Now, we need to ensure that all possible data are available by checking to make sure the sensors are functioning properly and that data are being sent via satellite to researchers who are using models to predict the severity of this event.
With early prediction of an El Niño, countries can adjust the types of crops that they grow, and plan in areas such as water resources, fisheries, and reserves of grain and fuel. Countries that have experienced the effects of El Niño in the past can also effectively plan in advance for drought, floods, and extreme weather, a consequence of the phenomenon, El Niño.
If you are a teacher, I’m writing a lesson plan related to the current El Niño conditions in the Pacific that you can use in your classroom. I will provide optional assignments so that you can use it from the middle school to college level. Please check my lesson plans in the next week to find this activity. Paul Freitag, Chief Scientist on board, is assisting with the exercise by providing current ocean temperature data and informed ideas.
I have remarked a few times today how helpful everyone is on the ship regarding questions that the new people have (that includes me!) or things that we need. This is a tremendous group of people. The Doc helped lower my bunk bed on the first day, after I spent 15 minutes trying every possible hole, button, lever, etc., until she discovered it was actually screwed into the wall. Doug McKay is helping me practice my knot tying which I started learning with my husband in Honolulu; I hope to be of some use on the RHIB or on the decks in the future when things need to be tied down.
John Kermond has answered every imaginable question, many times more than once. He has been very patient. The Chief Scientist endures my many inquiries about the TAO buoys and manages to come up with appropriate manuscripts and manuals whenever I need extra information. The Captain took the time to provide an overview of Pacific Ocean weather this morning before our test broadcast. It’s amazing how many questions I have each day. I even had to learn how to open the doors to go out on the deck. There is a lever that you lift to a certain point which allows you to exit; you then need to lower the lever again once you leave. This keeps the doors from flying open on their own and also keeps them water tight. I ended up sleeping with my stateroom door open the entire first night on the ship because I didn’t realize that it clicks shut only after much force. I woke up and the door was wide open. Taking a shower is always interesting. I’ve learned to stand with my feet wide apart to brace myself and I often use the walls for stability. Fortunately, I don’t even need to think about many of these details anymore. It’s remarkable how we all adjust to our surroundings.
Spiderman is the movie of choice tonight. I’m writing to you from my corner computer and peering out at a group of about 8 people sitting in the main lounge watching the movie. I haven’t watched any movies so far, but I am signed up for the game tournaments to start sometime later this week. In the first round I’m competing against the Commanding Officer (CO) in Scrabble (Yikes!), against the Chief Scientist in Yahtzee (Yikes again!), and am partners with our Cadet on board when we play Sequence. This is an evening program initiated by the Doc to keep morale high on the ship. Sounds good to me!
Well, I’m off to fold laundry before going to bed. Another outstanding day on the ship…I could really get used to this!
Hope all is well with you. Keep in touch!