Text version of Coastal Dynamics introductory video
Dr. Corene Matyas
Hi, I’m Dr. Corene Matyas, and I’m a climatologist. My research focuses on severe weather events and more specifically, on hurricanes.
Hurricanes are a collection of thunderstorms that form over warm ocean waters and are organized by the atmosphere and Earth’s rotation into a spiral shape. It is the low pressure in the storm’s center that causes air to flow inwards, and faster winds evaporate more water from the ocean and uplift it into the atmosphere where it condenses to form clouds and rainfall. Because air flows faster in circles of smaller radii, the fastest winds are located near the center of the hurricane.
My research looks at the rainfall that hurricanes produce. Unlike the more predictable pattern of winds, rainfall can be heavy in several places within the spiral bands of a hurricane, both close to the circulation center and over 100 kilometers away. Although moving over the land decreases wind speeds and removes the energy source of warm waters from underneath the storm, rainfall can actually be enhanced by the converging air as it slows down once over the rough land surface. The increased friction of the land surface causes air to Òpile upÓ, so that it has no choice but to rise up into the atmosphere, taking with it moisture from the ocean that can be converted into rainfall.
Measuring wind speeds and rainfall rates within hurricanes is a difficult job. Winds can be so high that they damage the very equipment used to measure them. Sometimes we have to estimate the wind speeds using debris that is left behind. We can look at trees that are damaged by the winds to help determine where the fastest winds occurred and in what direction or directions they came from. This can help us locate where the center of circulation tracked over land.
This weather station, equipped with a wind vane and anemometer for measuring winds, also has a tipping bucket rain gauge to measure rainfall rates. Water collects in the funnel and drains down into the hole into the bucket. Each bucket holds 0.01 inches of water. When it is full, it tips over and this motion is recorded to calculate the rainfall rate. Rain gauges like these are problematic because as fast winds blow inside hurricanes, the rain will not fall inside the bucket to be measured, so the rainfall totals measured by this device may be as much as 50% less than the actual amount that reached the ground. To obtain a better measurement, I can use this laser disdrometer. A laser beam extends between the two heads and hydrometeors block portions of the beam as they pass through. From the amount of beam blockage that occurs, we can tell how many hydrometeors passed through, and what ranges of sizes they were. This allows us to calculate a more accurate rainfall rate, even when winds are blowing very fast.
It is important for us to be able to accurately forecast where heavy rainfall will occur in advance of many types of storm systems, including hurricanes. This will allow us to evacuate flood-prone areas and save lives. The leading cause of death in the US from land-falling hurricanes is rainfall, not the winds and storm surge, as used to be the case. My research is working towards improving rainfall forecasts and minimize the destruction that hurricanes cause.
Dr. Arnoldo Valle-Levinson
Hello. I am Dr. Arnoldo Valle-Levinson, and I am an oceanographer. There are four different types of oceanographers: biological oceanographers, geological oceanographers, chemical oceanographers, and physical oceanographers. Biological oceanographers study all the kinds of life that exist in the ocean and the interactions of this life with the ocean. Geological oceanographers study the sediments and minerals in the ocean, how the sediments are distributed, and the implications of those sediments for the EarthÕs history. Chemical oceanographers study the chemistry of ocean water, the distribution of chemicals, and the effects of pollution on the ocean. Physical oceanographers study waves, tides, circulation in the ocean, and how the ocean interacts with the atmosphere. There are physical oceanographers who study large-scale phenomena like the effects of the ocean on climate change, like El Nino. I am a physical oceanographer who studies small-scale processes. I study estuaries. Estuaries are systems where fresh water from rivers and salty water from the oceans mix. This mixing creates a special type of circulation called estuarine circulation. This is a very challenging topic to study because estuaries are influenced by tides, winds, and the shape (or topology) of the Earth’s surface.
Why is estuarine circulation important? Estuarine circulation is important because many species of commercial and ecological importance, like blue crab, grouper, and flounder, depend on estuaries to complete their life cycle. For example, blue crab mature females go to the lower part of the estuary to release their eggs. The eggs are buoyant, which means they float to the surface. After the eggs float to the surface, estuarine circulation takes the eggs to the ocean. The young crabs travel up and down in the water column, and tidal currents and wind driven currents help the crabs return to the estuary to find food and shelter. This is why estuaries are called "nursery grounds" for many species.
Dr. Pete Adams
Hi. I’m sure most of you have walked on a beach along a coast or a lake or even a river. Have you ever wondered about the sand that you walk on? Where did it come from? Where’s it going? How does it move around?
Well, I think of these things ALL THE TIME. Actually, it’s my job to think about these things.
My name is Dr. Peter Adams and I’m a scientist. More specifically, I’m a geologist that studies how the surface of the Earth changes through time. That type of geology is called geomorphology: "geo-" meaning Earth, "morpho-" meaning change, and "-ology" meaning study of.
Why should we care about geomorphology? Geomorphology is responsible for the landscapes we live in. The mountains we hike in, the rivers we boat in, and the coasts where we recreate are all shaped by geomorphic processes.
My work as a geomorphologist is focused on measuring and modeling the rates and processes by which water, wind, and ice move material between rivers, coasts and oceans. I do this by setting up instruments that measure wave conditions, devices that measure ground motion, and cameras that document beach change. This is the measurement side of things. On the modeling side, I use high-powered computers to simulate how waves deliver energy and how the coast responds to this energy. This "modeling" technique helps scientists understand how changing one variable (e.g. wave height) can result in the change of another variable beach width.
In this module we present information about how beach morphology changes with wave conditions, and present two activities to give students an understanding of the dynamic processes operating along the coast.
The first activity involves going to the beach and measuring cross-shore beach profiles and beach sediment size. Students will learn how to measure beach topography, how to evaluate sediment size, and the relationship between sediment size and beach slope. Students can compare their results with large data sets that have been collected by numerous researchers all over the world.
We have also included background information on beach slope measurements, sediment properties, and sand budgets, as well as links to some websites that give excellent information on coastal processes and human interaction with the coast.
Given the strong links between climate change, coastal processes, and the proximity of large population centers to the coast (Miami, Tampa/St. Pete, and Jacksonville), coastal geomorphology is a topic that has great relevance for students in the state of Florida, and addresses several of the Sunshine State Standards.
Additionally, it will be clear how coastal geomorphology links to the modules that deal with hurricanes and coastal hydrodynamics.