The phrase “sea breeze” conjures up a variety of images for many people. Relaxing on the beach, a cleverly named cocktail, or even the familiar scent of a candle. For me, the term is a reminder of the extra effort I will have to put in when out bicycling in the Cleveland area. The term sea breeze and its counterpart land breeze refer to an atmospheric interplay between ground and water temperature, convection, and air pressure. This process results in a breeze that either blows toward or away from large water bodies depending on temperature and most often time of day.
Let’s get technical for a few moments. Sea breezes occurs because of the unequal heating rates of land and water. Open water which has been warmed by the sun all day cools at a slower rate than the adjacent coastal dry land. In turn the warm water heats the air above it by convection. The warming air expands becoming less dense creating a zone of low-pressure air. At the same time, the air over dry land cools quicker after sunset creating a zone of high-pressure air. The high-pressure air over dry land flows toward the low-pressure zone over water and the sea breeze is formed. The process is reversed in the afternoon. The sun warms the dry land at a faster rate than it does open water. Low-pressure air forms over land while high-pressure air forms over water and the land breeze develops flowing toward land. Basically, the sea or land breeze flows or advects toward the area which is cooler. This YouTube video provides a visual explanation. It is also important to note that the urban heat island effect present in large built environments can exaggerate the heating and cooling effect.
In my experience the Cleveland area land breeze and sea breeze are most noticeable in either the early morning or early afternoon, respectively. What this means to me as a cyclist is that I seem to be always pedaling into a headwind. Since I live in the City of Cleveland cycling in the summer involves leaving early to beat the heat and riding in a southerly direction away from Lake Erie battling the land breeze on the way out. By the time I get to my turn around point the inversion has occurred and I pedal into the sea breeze on the way home. While this phenomenon makes pedaling a bit more difficult the breezes provide a cooling respite during breaks and can ultimately make you a stronger cyclist. Here are some tips to beating the headwind. And if you can’t beat it maybe just celebrate it with your own personal take on a race like this one from the Netherlands.
Blog Author: Brent Eysenbach, Senior Program Manager