Overview and utility of the Vancouver 2010 and Snow-V10 monitoring metwork

An innovative monitoring network was established (i) to support the nowcasting service to meet the mandate essential federal service of safety and security of the public in a large event scenario, (i) to support the nowcasting service to the Vancouver Olympic Committee for the safe, efficient and fair operation of the sporting events, (iii) to support nowcasting research, (iv) to support scientific studies related to precipitation, visibility, and wind observations and (v) to support the validation of models and nowcasts for the Vancouver 2010 Winter Olympic Games. The alpine events were conducted at Whistler Mountain, which is located about 100 km from the west coast of Canada. The valley is about 650 m ASL and the mountain top is just above 2000 m. With warm coastal and complex terrain, substantial changes in the weather occurs below the mountain crest including strong wind intensities and direction, mid-level clouds, precipitation phase and intensity. The remote sensing component of the network included a valley Doppler C Band radar, an upstream wind profiler, vertically pointing K Band Doppler radars, ceilometers and a microwave profiling radiometer. This was supplemented by in-situ observation sites located along the mountain slope. Besides the usual meteorological measurements, these sites also included state of the art precipitation, visibility and wind sensors reporting every minute. An innovation was the fitting of a mini-weather station (measuring T, RH, and pressure) on a gondola that had a repeat time of about 40 minutes. A research specific site with about 30 different sensors was established to study fog, visibility, and low cloud characteristics. Examples of the utility of the observation network for nowcasting and science in complex terrain will be presented. With the coastal complex terrain requirements and the above normal warm winter, bright band detection to sense the rain-snow boundary was a critical weather feature. Detection of the inflow-outflow using Doppler radars and wind profilers were also important to nowcast phase change. Upslope and downslope wind flow was commonly observed and related to visibility and precipitation patterns. Radiometric profiling of relative humidity, water vapour and temperature helped with the nowcasting of low cloud. High temporal sampling with precipitation sensors demonstrated their value in validating high resolution model and estimating precipitation intensity and amounts.