The Variations of Wind over the Valley Topography of Baihetan Hydropower Station
-
摘要: 位居世界第二大的白鹤滩水电站地处金沙江下游峡谷区,频繁的大风给水电站建设和运行带来了严重影响。掌握水电站坝区大风变化规律,评估峡谷地形对风速的作用,有利于基于周围风场监测和预警峡谷区大风。根据水电站及周边观测资料,对坝区风的变化特征和峡谷地形作用进行了分析。(1) 峡谷区最高频率的风向和最大平均风速的风向均为顺着峡谷的偏南风或偏北风,且偏北风频率达55%以上,峡谷锁定了流经气流。(2) 坝区大风多发生在干季11月—次年5月,且夜间至清晨大风频率比日间高。干季峡谷风效应强,尤其在19时—次日08时。雨季峡谷风效应降低,局地山谷风增强,表现为山风比谷风持续时间长,08时和18时是山风和谷风交替时间。对应干季和夜晚大风频繁,说明峡谷风效应是影响大风的关键因子。(3) 通过狭管效应分析马脖子和葫芦口大桥两个站之间的风速关系,表明峡谷地形使马脖子站风速加强为葫芦口大桥站的1.27倍。利用多种拟合方法建立的两站风速关系表明,当葫芦口大桥站为5 m·s-1以下低风速,各方法都难以拟合峡谷区的风速,当风速在5.0~11.5 m ·s-1时,狭管效应对风速拟合最优,准确率超过70%,对11.5 m ·s-1以上强风速,多项式拟合效果较优,准确率接近65%。Abstract: Baihetan Hydropower Station, the second largest in the world, is located in a canyon over downstream of the Jinsha River. Frequent windy weather has an important impact on the construction and operation of the hydropower station. Based on the meteorological observation data around the hydropower station and its surrounding areas, this paper analyzes the variation characteristics of windy weather in the dam area, and uses the Canyon Wind Index (CWI) to evaluate the impact of terrain effect on the wind. The conclusions of the paper are as follows: (1) The most frequent wind direction and the average wind direction of the maximum wind speed at all stations of the dam area are either southerly wind and northerly wind, both along the direction of the canyon. The frequency of the northerly wind is higher than that of the southerly wind, indicating that the canyon terrain locks the direction of air flows. (2) Gales occur most frequently in the dam area in the dry season from November to May. The CWI shows that the effect of valley wind is stronger in the dry season than that in the rainy season. July to September is a transitional season that witnesses the change of the wind field, and the canyon wind effect is much weakened. The canyon wind effect is an important factor for the gales in the dam area. The daily variation of gale shows that the velocity is higher during the night and in the early morning than that in the rest of the day, and the canyon wind effect is more significant from 19:00 at night to 08:00 of the next day in the dry season. (3) The wind velocities of the northerly wind at the sites of Mabozi station and Hulukou Bridge in the dam area is compared, and the effect of narrow valley topography of the dam area on the wind speed is evaluated. It shows that when the air flow passes through the canyon, the velocity can be magnified by 1.27 times. The effect of narrow canyon can be best fit by the velocities of Mabozi and Hulukou Bridge when the velocity is between 5.0 and 11.5 m · s-1. For high velocities that are more than 11.5 m·s-1, however, the polynormal fit can better reflects the relationship of the velocities between the two sites.
-
Key words:
- Baihetan hydropower station /
- windy weather /
- canyon wind index /
- funneling effect /
- mountainvalley wind
-
表 1 马脖子站和葫芦口大桥站风速关系的拟合方程和效果检验
拟合方法 拟合方程 决定系数R2 狭管效应 U2 = 0.79U1 0.442 6 线性拟合 y = 0.68x + 0.14 0.474 7 多项式拟合 y = 0.05x2 + 0.08x + 1.54 0.507 8 指数拟合 y = 1.11e0.17x 0.492 7 -
[1] 陈文龙. 白鹤滩水电站极端大风天气成因分析[J]. 农业与技术, 2018, 38(23): 138-141. [2] 张俊兰, 张莉. 一次天山翻山大风天气的诊断分析及预报[J]. 沙漠与绿洲气象, 2011, 5(5): 13-17. [3] 苗爱梅, 贾利冬, 武捷. 近51a山西大风与沙尘日数的时空分布及变化趋势[J]. 中国沙漠, 2010, 30(2): 452-460. [4] 潘新民, 祝学范, 黄智强, 等. 新疆百里风区地形与大风的关系[J]. 气象, 2012, 38(2): 234-237. [5] 李燕, 程航, 吴杞平. 渤海大风特点以及海陆风力差异研究[J]. 高原气象, 2013, 32(1): 298-304. [6] 范元月, 张家国, 枚雪彬, 等. 三峡坝区一次冬季持续性晴空大风的成因分析[J]. 暴雨灾害, 2022, 41(2): 184-191. [7] 陈红玉, 钟爱华, 李建美, 等. 风廓线雷达资料在强降水预报中的应用[J]. 云南地理环境研究, 2009, 21(5): 63-68. [8] 秦丽, 李耀东, 高守亭. 北京地区雷暴大风的天气—气候学特征研究[J]. 气候与环境研究, 2006, 11(6): 754-762. [9] 梁钟清, 张艳霞, 钟水新, 等. 地形对一次粤北暖区暴雨的影响研究[J]. 热带气象学报, 2023, 39(4): 536-550. [10] 陈芳丽, 刘显通, 曾丹丹, 等. 珠三角北部一次暖区强降水过程中的地形作用[J]. 热带气象学报, 2022, 38(3): 377-386. [11] 张志田, 谭卜豪, 陈添乐. 丘陵地区深切峡谷风特性现场实测研究[J]. 湖南大学学报(自然科学版), 2019, 46(7): 113-122. [12] 刘雅楠, 徐海明, 张乐英. 冬季东太平洋峡谷风的季节内变化及相联系的海气特征[J]. 大气科学学报, 2020, 43(2): 287-298. [13] XIE S P, XU H M, KESSLER W S, et al. Air-sea interaction over the eastern Pacific warm pool: gap winds, thermocline dome, and atmospheric convection[J]. J Climate, 2005, 18(1): 5-20. [14] 傅抱璞. 河谷内的风速[J]. 气象学报, 1963, 33(4): 518-526. [15] 李永乐, 唐康, 蔡宪棠, 等. 深切峡谷区大跨度桥梁的复合风速标准[J]. 西南交通大学学报, 2010, 45(2): 167 - 173. [16] 洪新民, 郭文华, 熊安平. 山区峡谷风场分布特性及地形影响的数值模拟[J]. 长安大学学报(自然科学版), 2017, 37(5): 56-64. [17] 范维, 居志刚. 白鹤滩水电站坝区大风特征分析[J]. 人民长江, 2013, 44(19): 32-35. [18] 姚增权, 李智边. 三种实时计算风向标准差方法的比较[J]. 应用气象学报, 1990, 1(3): 324-330. [19] 董安祥, 胡文超, 张宇, 等. 河西走廊特殊地形与大风的关系探讨[J]. 冰川冻土, 2014, 36(2): 347-351. [20] 胥雪炎, 李补喜. 不同被解释变量选择对决定系数R~2的影响研究[J]. 太原科技大学学报, 2007, 28(5): 363-365. [21] 赵婉露. 遵义地区循环系统疾病对天气与气候变化的响应及预测应用研究[D]. 成都: 成都信息工程大学, 2019. [22] 贾春晖, 窦晶晶, 苗世光, 等. 延庆-张家口地区复杂地形冬季山谷风特征分析[J]. 气象学报, 2019, 77(3): 475-488. [23] 张人文, 范邵佳, 李颖敏. 2008年秋季从化山谷风观测研究[J]. 热带气象学报, 2012, 28(1): 134-139. [24] WHITEMAN C D. Mountain Meteorology: Fundamentals and Applications[M]. New York: Oxford University Press, 2000: 355. [25] 王云飞, 汪斌, 李永乐. 水库蓄水对山区桥址风特性的影响[J]. 西南交流大学学报, 2018, 53(1): 95-145.