Steam Fog on an Autumn Morning in Blacksburg, Virginia
November 07, 2010
During autumn, steam fog rising over ponds and lakes is almost as common as falling leaves. Due to thermal inertia, the water temperature is typically higher than that of the ambient air, thus its equilibrium vapor pressure is higher. When the liquid evaporates and rises into the cooler air, it eventually cools to that of the air temperature, condensing just above the water surface. The air temperature at the time the photo was snapped was 40 degrees F (4.5 C). Note the gold-orange leaves belong to a willow oak tree (Quercus phellos), and the lavender flowers are native purple asters (Symphyotrichum patens). Photo taken in Blacksburg, Virginia on October 28, 2010 at 8:49 a.m. Eastern Daylight Time.
Photo details: Camera Maker: Canon; Camera Model: Canon EOS REBEL T1i; Focal Length: 35.0mm; Aperture: f/8.0; Exposure Time: 0.013 s (1/80); ISO equiv: 100; Exposure Bias: none; Metering Mode: Matrix; Exposure: Landscape Mode; White Balance: Auto; Flash Fired: No (Manual);Color Space: sRGB.