"as, the icy fang
And churlish chiding of the winter’s wind...
Even till I shrink with cold, I smile"
Duke in As You Like It (2.1.2)
During the winter months, materials used in every day life shrink. Rubber, plastic, metals, and concrete contract, causing head aches for architects and engineers. Car tires deflate slightly because of the contracting air inside. We may not enjoy this as much as Shakespeare's Duke, but we learn to deal with it.
The natural world is also vulnerable to the effects of the cold. Water, the building block of life, contracts by roughly 0.2% from summer into winter. This may seem like a minor change but it can have a noticeable effect on large volumes of water.
The Hudson River Estuary is a large body of water that is connected to an even larger body of water, the Atlantic Ocean.The contraction of this large water mass by as little as 0.2% results in a noticeable change in water level. Using HRECOS data, we can observe a decline in the Hudson River water levels every winter and a rise in water level every spring and summer.
Why is this important? Knowing how to measure the thermal contraction and expansion of the Hudson River water enables us to evaluate other environmental influences accurately. In order to observe the impact of a drought or global warming, for example, we first need to filter out the noise of seasonal cycles.
Another reason why this phenomenon is important is because of its role in sea level rise. According to some estimates, global sea levels are rising at a rate of 3.1 mm per year and that half of this rise is due to the thermal expansion of the water itself (Antov, Levitus, and Boyer, 2005).
There are multiple influences on water level in the Hudson River. For that matter, there are multiple influences on all of the parameters we measure. The Hudson River is a rapidly changing and complex system. One of the primary goals of HRECOS is to provide high frequency data that will allow users to filter and understand the many factors that define this familiar yet mysterious river system.