( Various images of Hector )
I was fortunate to assist and aid the esteemed photographic/video artist from Sydney, Murray Fredericks who has been visiting Darwin for the past 6 seasons camping on the Tiwi Islands in a remote location capturing time lapse and still imagery for his ‘Hector Project’ exhibition which has been showcased in Australia, England and Germany. Murray was finalising and collecting more unique images of Hector for clients and his galleries using a PhaseOne XF 100MP camera – truly one of the world’s finest professional units.
You can view Murray’s exquisite work here:
Technical text courtesy: N Andrew Crook – National Center for Atmospheric Research, Boulder, Colorado
Hector is the name given to a thunderstorm complex that develops regularly over the Tiwi Islands just north of mainland Australia during the transition season (Nov–Dec, Feb–Mar). The Tiwi’s consist of two relatively flat islands (Melville in the east, Bathurst in the west), which together cover approximately 150 km in the east–west direction and 50 km in the north–south direction. Convective activity maximizes during the afternoon indicating the importance of diurnal heating. The storms, which are easily visible from Darwin 100 km to the south, are among the world’s tallest often reaching a height of 20 km.
The regular occurrence of the storms over isolated, basically flat, terrain makes the islands an excellent testing ground for observational and modeling studies. The storms have been the subject of two recent field pro- * The National Center for Atmospheric Research is sponsored by the National Science Foundation. Corresponding author address: Dr. N. Andrew Crook, NCAR, P.O. Box 3000, Boulder, CO 80307. E-mail: email@example.com grams: Island Thunderstorm Experiment (ITEX) in 1988 (Skinner and Tapper 1994) and Maritime Continent Thunderstorm Experiment (MCTEX) in 1995 (Carbone et al. 2000).
These field programs successfully characterized the structure of convection over the Tiwi Islands in various flow regimes. They also gave an idea of the functional relationship between convective strength and various external parameters, although the small sample size of the dataset limited the conclusions that could be drawn. Numerical simulations of the Hector convective system have been performed by Golding (1993) and Saito et al. (2001). Golding (1993) used the U.K. Met. Office’s mesoscale model at 3-km resolution to examine two cases from ITEX and was able to simulate the development of deep convection over the islands.
Deep convection develops over the heat source when a moisture profile with positive convective available potential energy (CAPE) is added to the nonlinear model. The sensitivity of the convective strength (defined by the accumulated rainfall and total condensate) to wind speed and direction, surface fluxes, and low-level moisture is then examined. It is shown that the strength increases as the wind speed decreases and as the wind direction turns toward the major axis of the island, in agreement with the prediction of increased low-level convergence from the linear and nonlinear dry models. Sensitivity experiments indicate that the convective strength increases as both the heat and moisture fluxes increase. The strength is more sensitive to the heat flux since this drives the large-scale convergence and sea breezes that generate convection. As the low-level moisture in the upstream sounding increases, the accumulated rainfall over the islands increases monotonically; however, the total condensate reaches a maximum at a CAPE of around 1500 J kg 21 and then decreases thereafter. It is shown that the low-level moisture is an important predictor of the form of convective development. Finally, simulations with a single coastline are performed to show that one of the reasons the Hector convective system is so strong is that it develops over an island where the land–sea circulation from all coastlines can contribute.
Lightning images as we flew around Hector and a behind the scenes video link below.