低空急流季节性日变化特征对塔克拉玛干沙漠风能利用的影响

Impact of seasonal diurnal variation characteristics of low-level jet on wind energy utilization in Taklimakan Desert

摘要

随着风电机组的高大化发展，风机轮毂高度已进入低空急流最大风切变影响范围。新疆塔克拉玛干地区作为中国重要的风光能源基地，上空广泛分布偏东方向的低空急流。为加深对塔克拉玛干地区低空风场的认识，厘清低空急流对风能利用的潜在影响，利用2017年ERA5模式层逐小时再分析资料，针对塔克拉玛干地区的风廓线特征并结合低空急流的定义，依据最大风速上下垂直切变、距地面高度及风速阈值，给出了强、弱低空急流的判定条件，并通过低空急流覆盖范围和持续时间定义了低空急流日的判定标准，结合多窗口能谱密度估计方法，对新疆南疆塔克拉玛干地区的东风低空急流季节内变率和季节变化特征进行分析。结果显示：2017年共有183 d符合出现低空急流的判定条件，夏季(50 d)最多，冬季(11 d)最少。结果表明：塔克拉玛干沙漠上空低空急流仅在日时间尺度上存在显著的周期性，不同季节强、弱低空急流风速和高度的日变化趋势基本相同，但在风速大小上存在差异，表现为春、夏强于秋、冬，强低空急流主要为夜间低空急流。

Abstract

With the development of the wind turbines becoming taller and taller, the height of wind turbines has entered the range of maximum wind shear influence of low-level jets. As an important wind and solar energy base in China, the Taklimakan region in Xinjiang is widely distributed with low-level jets in the east direction. In order to deepen the understanding of the low-level wind field in the Taklimakan region and clarify the potential impact of low-level jets on wind energy utilization. Using the hourly ERA5 reanalysis model level data in 2017, based on the wind profile characteristics of the Taklimakan region and the definition of low-level jets, the criterion to identify the strong and weak low-level jets is given based on the height and vertical shear of the maximum wind speed and wind speed threshold. The determination criteria for low-level jet day is defined through the coverage and duration of the low-level jets. The spatiotemporal distribution and intraseasonal variation characteristics of the low-level jets in the Taklimakan desert were analyzed. In 2017, there were 183 days that met the conditions for the criteria of low-level jets day, with the most days in summer(50 days) and the fewest days in winter(11 days). The result show that the low-level jets over the Taklimakan Desert has significant periodicity only in the diurnal scale. The diurnal variation trends of wind speed and height of strong and weak low-level jets in different seasons are basically the same, but there are differences in wind speeds. It is stronger in spring and summer than in autumn and winter.

关键词

低空急流 / 塔克拉玛干沙漠 / 日变化 / 风能利用 / 多窗口能谱密度估计

Key words

low-level jet / taklimakan desert / diurnal variation / wind energy utilization / multitaper power spectral density estimation

Author summay

韩梓航(1994—), 男, 工程师, 博士, 主要从事中尺度数值模拟与预报。E-mail: [e-mail]

基金资助

湖北省自然科学基金(2022CFD170)