NOAA Teacher at Sea
Laura Grimm
Aboard NOAA Ship Thomas Jefferson
July 4 – July 22, 2022
Mission: Hydrographic Survey of Lake Erie
Geographic Area of Cruise: Lake Erie
Date: July 21, 2022
Weather Data from the Bridge
Weather Data from the Bridge
Latitude: 41ᵒ 36.7’ N
Longitude: 080ᵒ 40.3’ W
Sky Conditions: Few clouds
Visibility: 10+ miles
Wind Speed: 15.3 knots
Wind Direction: 254ᵒ W
Lake Temperature: 23.6 ᵒC
Wave Height: 3 feet
Dry Bulb: 26.2 ᵒC
Wet Bulb: 22.8 ᵒC
Calculated Relative Humidity: 75%
Science and Technology Log
Humidity: In each blog post, I report the dry bulb and wet bulb temperatures plus the calculated relative humidity.
What is humidity? It is the amount of water vapor in the air. If there is a lot of water vapor in the air, the humidity will be high. The higher the humidity, the “stickier” the air feels outside. Think about a hot August day in Ohio. The air feels sticky and uncomfortable. Chances are that the humidity is high.
What is relative humidity? Relative humidity is the amount of water vapor in the air, expressed as a percentage of the maximum amount of water vapor the air can hold at the same temperature. Warm air can hold more water vapor than cool air. Once you know the wet-bulb and dry-bulb temperatures, you can use a conversion table to calculate the relative humidity. (I discussed this topic in my July 7: Echoes and Flares blog post.)
This video might help you understand the concept further.
These thermometers are used to measure the dry bulb (left) and wet bulb (right) temperature measurements. The dry bulb measures air temperature. The wet bulb thermometer has a tiny sock on the end that is sitting in a container of water. The physics of water evaporating causes the temperature to decrease. So, this thermometer will register a lower temperature. A person then uses a comparison cart to calculate the relative humidity. The dryer the air, the more quickly the water from the sock will evaporate. A larger difference between the dry and wet bulb thermometers will result in a lower relative humidity reading.
Students: We have a “wet wall” also known as a “swamp cooler” in the greenhouse to cool the greenhouse when it gets too warm. How is this related to humidity? How does this work to cool the greenhouse? (Hint: Look up the concept of evaporative cooling.)
Latitude and Longitude: Each time I write a blog post I have told you where I am. I do this by telling you my “address” on the globe by listing the ship’s latitude and longitudinal lines. But just what are latitude and longitude lines and how do they tell you where you are on the globe?
Latitude and longitude are a system of lines used to describe the location of any place on Earth. Think of latitude and longitude as an imaginary grid placed over the world to help you find places. Each place on the Earth has an address. The address is where the lines of latitude and longitude cross. Although these are only imaginary lines, they appear on maps and globes as if they actually existed.
- Latitude are the points north and south of the equator. The equator is halfway between the North and South Poles. It’s an imaginary horizontal line that cuts the planet completely in half. Latitude lines are imaginary lines that are a specific degree away from the equator going to the North and South Pole. Between each line of latitude there are 60 minutes which are then again subdivided into 60 seconds.
- They are also known as “parallels” and run east-west.
- Equator = 0ᵒ; North Pole = 90ᵒN; South Pole = 90ᵒS
- Northern Hemisphere = 0ᵒ through 90ᵒNorth
- Southern Hemisphere = 0ᵒ through 90ᵒSouth
- 1 degree of latitude = 60 nautical miles
- 1 minute of latitude = 1 nautical mile
- 1 nautical mile = 1.15 statute miles (Statute miles are used on land.)
- Longitude are the points east and west of the prime meridian. Like the equator, the prime meridian is an imaginary vertical line that splits the world in half from the North to the South Pole. Longitude are vertical lines going from one pole to the other starting at the prime meridian. I like to think of the lines of longitude like the distance between the edges of sections of an orange. They are further apart near the middle (equator) and get closer together as they near the ends.
- 0ᵒ = the Prime Meridian that passes through Greenwich, England
- 180ᵒ = halfway around the Earth; it is roughly the international dateline
- Western Hemisphere = 0ᵒ through 180ᵒWest of Greenwich
- Eastern Hemisphere = 0ᵒ through 180ᵒEast of Greenwich
- Longitudinal lines vary with distance from the equator
This video may help you understand these concepts more clearly.
What is the latitude and longitudinal address of your town? Use this interactive map to find the latitude and longitudinal address of your house! I found using the “satellite” view handy.
Another way to find out is to go to Google Maps and type in your address. Once the App has found your house, right click on the red pin. At the top of the list will be your latitude / longitude coordinates.
Chizzywinks: This message was recently written on a white board outside of the crew lounge. What are these invaders? They do not seem to bite; however, they are very annoying. They are everywhere!
No one on board seemed to know what they were (other than annoying), so I contacted two friends back home. Drs. Rowe and Nault have expertise in plant pathology and entomology – but, more importantly, they are fly fishermen and really know about the insects that call Lake Erie “Home”.
These lovely, pesky insects are midges. They have many other names, including lake flies, Canadian soldiers, or chizzywinks, just to name a few. They live on the lake bottom as worm-like larvae, many of which are blood red. In this life stage they eat decaying plant matter. Eventually, they enter the pupal stage. This is a nonfeeding stage between the larva and adult, during which it undergoes a complete change within a hardened case. The pupae (more than one pupa) slowly rise to the surface through the water column. They are a major source of food for fish and other aquatic animals. Fishermen consider them good bugs! Those aboard NOAA Ship Thomas Jefferson might beg to differ.
Once at the surface, the adults emerge and get rid of their pupal cases in the surface film of the water. They often emerge by the thousands. In fact, in certain places around the world there can be so many midges that once they die, they are considered fertilizer.
The adults look like “mosquito-like” flies, but don’t bite. Many are eaten by birds.
Once the larvae emerge as flying adults, they stop eating and have only one thing on their minds – mating. According to Water Blogged, a blog published by the Science and Stories of the Center for Limnology at the University of Wisconsin-Madison, the adults “gather in huge clouds and, well, get to know one another. After mating, the male eventually expires, with the female not far behind – but first she’ll return to the water to lay her eggs.” The eggs laid on the surface sink to the bottom, and the cycle begins again.
(Students – Compare and contrast the life cycle of a midge and the monarch butterfly or darkling beetles.)
Learn more about the midge in this video.
Meet the Crew
Justin Witmer has worked on NOAA Ship Thomas Jefferson as the Chief Electronics Technician for the past 3 years. Prior to this position he worked for the Norfolk Naval Shipyards. He is a sailor at heart having spent 20 years in the U.S. Navy.
What does your job entail? He is responsible for most of the things on TJ that plug into a wall. This includes the maintaining and repairing the sonars (which are essential to the hydrographic work), other ship sensors, computers, etc. From the sonar on the keel to the wind bird at the top, he is responsible for the electronics in between.
Where do you do most of your work? I work mostly from my office which is right off the Survey Control Room where I do computer and user account maintenance as well as electronics troubleshooting duties.
What do you like most about your job? I like to troubleshoot electronics issues.
What do you like the least about your job? Administrative paperwork.
What do you like about working on a ship? I’ve always enjoyed the general atmosphere of living on a ship. With a good crew it is much like a large group home. You can choose to get along with everyone, and if you can’t, the ship is large enough that you can generally get away from those you don’t see eye-to-eye with.
If budget was not an issue, what tool would you like me to invent that would make your job easier? A cable stretcher.
Can you share with us one or two things about yourself that don’t have to do with work? He lives in Norfolk, VA, speaks fluent Turkish, and like to play music (bass and tuba). He also likes amateur radio. His job lines up nicely with his hobbies – all except, perhaps, playing tuba.
So much of what TJ does to complete its mission relies on computers, sensors, and electronics. Thank you, Justin, for all you do to keep the electronics aboard TJ ship shape! Thank you for your service.
Personal Log
Safety is paramount. Since discussing safety drills in my July 8, 2022 blog, I have done my homework. I know what the signals mean, what to take, and where to go. Today, we had three drills: fire, man overboard, and abandoned ship. During abandoned ship drills, we need to take our personal flotation devices (PFDs), also known as life vests, and our Survival Immersion Suit which is lovingly called our “Gumby” suit. We are expected to put on our suit in less than 2 minutes. It is made from Neoprene to maximize flotation and hypothermia protection. Being red, it can easily be seen in the water. It also has a light and a place where we can blow up a head pillow.
A friend helped me practice putting on my Gumby suit. I succeeded in putting it on I just over a minute!
Q: Where is Dewey? Hint: He is sitting on a very important piece of equipment that we need when we want to lower or raise the anchor.
A: Dewey is sitting on the anchor windlass. According to Wikipedia, “An anchor windlass is a machine that restrains and manipulates the anchor chain on a boat, allowing the anchor to be raised and lowered by means of chain cable. A notched wheel engages the links of the chain or the rope.” In other words, it is the machine that lowers and raises the anchor.
I learned a lot new information today! The steel pipe on each side of the windlass where the anchor chains pass through is called a hawsepipe. I think because the chain goes up and down in the hawsepipe, a hawsepiper (*) refers to a ship’s officer who began his/her career in a non-traditional way. They did not attend a maritime academy to earn an officer’s license. They worked their way into their career like a chain travels through a hawsepipe.
(*) Remember this word. I will be using it in a future blog post.
The anchor is usually very heavy and made of metal. It is used to help keep the ship from drifting away from a fixed place due to wind or current.
TJ has a stockless anchor. Watch the following video to see how a windlass and a stockless anchor work together to secure a ship. The chain really does a lot of work!
Lake Erie Fact:
Lake Erie’s primary inlet is the Detroit River which comes from Lake Huron. Its natural outflow is via the Niagara River, which provides hydroelectric power to Canada and the U.S. as it spins huge turbines near Niagara Falls.
Soon we will start sampling the bottom to see if we are traveling over mud, clay, sand, gravel, or shells (most likely to be zebra mussels). This is important information for ships to know who want to anchor in the area.
I have mixed feelings about this experience coming to an end. I really miss my husband, friends, cats, home, garden, etc. Just this morning, I made the comment to Chief Hydrographer in Charge, Erin, how this has been an incredible experience . . . especially for a nerd who is super excited about STEM content and promoting STEM careers. With minimal preparation, I was plopped into this information-rich environment with local experts who were willing and excited to answer all my questions AND I had the time to ask more questions, follow research leads, process my learning through writing, and get a taste of living at sea.
We pull into the Port of Cleveland on July 22. It will be hard to say, “Good-bye” to TJ, this extraordinary learning experience, and all my new friends. It will be easy to greet my husband after 19 days being away. It will also be time to move forward and plan on how I will share what I have learned with the students at Dalton Local Schools.
It’s been a full day. Ta-Ta for now!
