Characteristics of daily extreme-wind gusts along the Lanxin Railway in Xinjiang, China

Severe wind is a major natural hazard in Xinjiang Uygur Autonomous Region, China. Using a 55-station network, we collected wind statistics along the Lanxin Railway, particularly in the Alashankou, 30-li, and 100-li wind zones. Wind speed and direction varies throughout the province: the mean speed of extreme wind gusts is greater in the north where wind direction is mainly western and northwestern; in the south the wind direction is primarily northeastern and southeastern. Detailed analyses show that the prevailing direction of extreme winds follows the gaps of the mountain. The terrain effect enhances wind speed and creates the three wind zones. Severe winds occur mostly in during April and August and are caused primarily by Siberian cold fronts (spring) and thunderstorms (summer). We analyzed the probability of extreme wind speed using the Gumbel Model, and calculated annual maximum daily extreme wind speed values for the three wind zones over desired return periods.