2008-12-20 00:07:36.000 – Ryan Knapp, Staff Meteorologist
My life on the summit is surrounded by darkness. Not the metaphorical type but literally the darkness of the night. My shift currently starts in darkness and ends in darkness. We work twelve hour shifts up here with my shift starting at 1730 EST and ending at 0530 EST the following day. The sun on the summit official sets at around 1615 EST and doesn’t rise again until a bit after 0700 the following morning. So from December 17 until December 27, the summit only receives about nine hours and three minutes of daylight with the remaining 14 hours and 57 minutes totally devoid of sunshine. But there is light at the end of tunnel and it all occurs on the 21st.
December 21st marks the first day of winter which corresponds with the winter solstice at 0704 EST marking the shortest day of the year. After this date, the days will slowly begin to increase once again nudging back into my shift allowing me to witness the sunrises and sunsets without having to wake up earlier or go to sleep later. I am not saying that I sleep 12 hours when I am up here and haven’t seen a sunrise or sunset in months but I usually have to choose one or the other. But luckily I don’t miss too many since we are in the fog over 50 percent of the year with most of that occurring in the winter. So, most of the time sunrises and sunsets are just marked by the clock and the changing in the shades of grey in the fog. So it is like a tree falling in the woods with no one around to hear it, does it make a sound? Well on the summits, it goes: If the summit is in the fog and we were unable to see the sunrise/set, was there a sunrise/set? Of course the answer is yes but in the literal since, no. So, when visitors ask if there is going to be a sunrise in the morning, we usually answer yes but we just won’t get to see it.
But while we are on the subject of sunrises and sunsets, it should be noted that the latest sunrise and earliest sunset do not occur on the shortest day of the year. In fact, the earliest sunset has already occurred on the seventh of December setting at 1612 EST. The latest sunrise occurs on the third of January at 0715 EST. But why the discrepancy and why do they not occur on the solstice? Well it all comes down to our clocks and how we measure time, the earth orbit and the earth rotation. We use atomic clocks to keep track of times where as a day measured from true solar noon (sun at highest point) to true solar noon the following day exceeds 24 hours in length. Therefore, the sunrise/set appears to be later/earlier in relation to our time pieces. The discrepancies between these times eventually add up, and to keep things “lined up,” we have leap years to keep calendar years in sync with astronomical and seasonal years. The earth’s orbit is not a perfect circle. And lastly, the rotation of the earth is slightly faster in winter in conjunction with the “wobble” of the earth. So after reading this, hopefully you don’t feel so much in the dark as you were prior to reading this.
Ryan Knapp, Staff Meteorologist