Our official cut-off for environmental conditions is a wind speed of 17 knots. However, ideally we would like to be surveying in a Beaufort less than 4. The Beaufort is a scale of wind speed and describes sea state, 4 being a moderate breeze with between 11 to 16 knots of wind and 4 foot waves. However, this varies dramatically depending on which direction the wind is blowing from. If it is an easterly wind, coming from offshore, it has a high fetch, which is the length of water over which wind blows unobstructed. With a westerly wind coming off the land, we may have a low sea state close to shore but as we get to the end of our lines it starts to get choppier, this is because the land is acting as a barrier, but as the wind blows across the water it gradually causes the waves to build.
I wake up at 0645 every morning and open the various marine and aviation web sites that give me an insight into observed and forecast conditions. I check NOAA's national data buoy center for the two buoys that best describe our survey area; Grays Reef and St. Augustine, which update every hour. I call Fernandina Beach Municipal airport to get an automated weather observation telling me how high the ceiling is. We fly at 1000 feet so we need the cloud cover to be at least at 1200 feet or else we will be flying in and out of the clouds. Fog and haze greatly reduce our visibility, and we need a minimum of 2 miles visibility whilst flying our transect lines. 'Patchy' fog is not ideal but can be OK, we just need to go off watch when visibility is reduced to 1nm or less, but could still get a majority of the survey flown in good conditions.
On Dec. 15th, the period of high winds finally ceased, bringing a new issue to contend with. It was foggy in the morning (see picture) and from our field station, conveniently located on the beach, we couldn't even see the pier which is 2 miles to the south. The forecast was for the fog to get worse later in the day, so we seized the moment and took off at 1000. Surprisingly, when the plane got up, they reported back over the marine radio that they had 4 nautical miles of visibility, the seas were flat calm and there was no glare due to the overcast skies - ideal conditions for finding and photographing whales. We had three sightings during the survey flight, including a few favorites, Piper and Picasso, spotted a mile and a half southeast of the St Mary's sea buoy. We also had a very special new mom, Mavynne! Get more information on her by searching for EG #1151 in the Right Whale Catalog. She must have given birth to her sixth calf some time between December 6 (seen alone) and December 15. (Keep reading blogs for history and updates on Mavynne). The day turned out to be long, but very worthwhile.
Yesterday, we were confounded by yet another fog bank, this time we couldn't even see past the surf on the beach - 'sea fog'. This is a type of advection fog that is caused from warm air traveling over colder water, resulting in cooling of the lower layer of air that hangs over the water as fog. When the temperature doesn't rise significantly, and there's no wind, this will linger. By midday it appeared to clear slightly so we quickly jumped into action, and were shortly in the sky only to see a layer of fog stretching out to the horizon. So we had to count our losses, turn around and head back for the airport. Today is calling for more of the same, so we sit, fogged in and frustrated, at this festive Fernandina field site! But it's not all bad, we have caught up on photo analysis, and we are all keeping spirits high since we know we should make the most of this down time. We will be well prepared for when January comes around and we don't have time to catch our breath. So we wait and we wait ...
1) View from our back porch on a clear day.
2) Aerial photo of a Beaufort sea state 2 - ideal conditions for survey.
3) Aerial photo of a Beaufort sea state 6 - we should not be flying!
4) View from our back porch on a foggy day.