On one of my few daily excursions out of my house during this time of COVID-19 and stay at home orders, I go for a run. Some days, I run through my neighborhood, down a steep hill, past a paper factory, and onto Ediz Hook, a long, narrow piece of land that stretches into the Salish Sea.
It's a beautiful place to run—there is a strip of sandy beach on the side hugging Port Angeles Harbor and a strip of rocks against which waves crash on the other side, reminding me of Maine’s rocky coast. A mile or so in, a trail begins winding its way through the beach grass. I follow this trail, and the stresses of the global pandemic and my own hazy future fade away. Before I know it, I reach the end. The Coast Guard Station, armed with gargantuan boats and a solid gate loom ahead. I pivot, take a breath, and start my voyage back.
I am immediately hit with the force of a wind that I hadn’t before realized was on my back. Each lift of my legs and each pump of my arms is resisted by this powerful wind. And this happens every time I run here. So, why is the wind always blowing against me as I run back towards the land? One explanation is that it is a sea breeze. Sea breezes blow towards the land during the day, and their sisters, land breezes, blow towards the sea during the night. Ultimately, they result from the different speeds at which the land and the sea warm and cool. The sea warms and cools more slowly, causing it to be cooler than the land during the day and warmer than the land during the night. As cool air is more dense than warm air, this creates a pressure gradient. During the day, the cool, more dense air above the sea flows towards the warm, less dense air above the land. As it moves inland, the cool air displaces the warm air. The displaced warm air cools as it rises, becomes more dense, and flows towards the less dense air above the sea. With this, a sea breeze circulation cell is formed, and the cycle repeats. I return to my house breathless, sweaty, and ready to drop. Meanwhile, the sea breeze blows on, unknowing and uncaring.
Miller, S. T. K.,Keim, B. D.,Talbot, R. W., andMao, H.(2003),Sea breeze: Structure, forecasting, and impacts,Rev. Geophys.,41, 1011, doi:10.1029/2003RG000124,3.