SOARING SEA BREEZES IN NORTHLAND NEW ZEALAND
WEST COAST SEA
THE By Paul Rockell
It is a part of the country most of us don’t know much about and its challenges are unique. As promised last month, this is the first of two stories on flying the sea breezes that form along the skinny piece of land at the top of the country. End of front near Whangarei Heads
Whangarei under the seabreeze
In the north of the North Island of New Zealand is a three hundred kilometre long peninsula. In essence this runs north to south and is only seventy kilometres at its widest. It rises high on basement greywacke to twelve hundred feet in the east and falls rapidly to the Pacific Ocean. The land to the west falls gradually to the Tasman Sea only interrupted by ancient volcanic remnants often joined over great distances by consolidated sand tombolos. Being subjected to high rainfalls and warm temperatures and never experiencing glaciations, most of Northland is characterised by eroding rolling hills either covered in native bush or exotic pinus radiata. The valley floors are intensively farmed, mostly dairying, but with fields quite large enough for landing gliders. Most New Zealand glider pilots have little knowledge of what is available to gliding up here, no more than us Northlanders know anything about mountain peaks, snow and wave. This is a small account of some of the climatic features we are blessed with in this small area of New Zealand. Northland is quite uncluttered with air space regulations and in my view is a soaring paradise to those with the old pioneering spirit. Do not all come at once. As the sun comes up on a summer’s day, I check the view towards the east coast. If the Northland peninsula is free of cloud with maybe a little valley mist but out at sea there are towering cumulus, that’s a sure sign the day is going to be a very soarable and more than likely involve sea breeze and convergence. On a good summer’s day in the north with our long coastlines and large harbours, there are myriads of sea breeze fronts and general convergences all with their differing cloud bases and characteristics to be explored. West Coast Sea Breeze From mid December to mid March, when the ground has dried out sufficiently and the equinoctial winds are long gone: if the anticyclonic high pressure is centred on us or Map showing the usual position of the leading edge of the West Coast sea breeze front.
not too far south, the wind that day will favour us with a slight easterly breeze. All that day’s heat will flow towards the western side of Northland to meet the cool moist air sucked in off the Tasman Sea, producing one of our better sea breezes. Very occasionally this will run the length of Northland, over three hundred kilometres long. Most likely it is the original long white cloud of Aotearoa as seen from the first arriving canoes. If the day heats up nicely, at midday I will take a peek over the homestead ridge to observe the cloud development in the interior. At about the same time the east coast sea breeze will be pulling back inland and overhead the dairy farms and airstrip where I live some fifteen kilometres from the sea. Gliders need to launch quickly at this time before the thermals move too far inland. For me, after a leisurely lunch, it is a simple
The west coast sea breeze beyond the Tangihuia hills south of Dargaville
14
August 2009
matter of filling up a drink bottle, stowing fruit bars, rounding up Helen and any stray grandchildren and off to the DG400’s T hangar, pull out GNZ and go, usually getting
