Collaborative Research: Understanding the Influence of Turbulent Processes on the Spatiotemporal Variability of Downslope Winds in Coastal Environments

合作研究：了解湍流过程对沿海环境下坡风时空变化的影响

• 批准号: 2331728
• 负责人: Leila Carvalho
• 金额: $ 89.77万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2331728&HistoricalAwards=false
• 关键词: Collaborative; Research; Understanding; Influence; Turbulent

Downslope windstorms in coastal terrain have resulted in many serious wildland fires. The overall conditions leading to those windstorms are well-known, however the details about the timing and severity of the winds are difficult to forecast due to a lack of knowledge about the small-scale mechanisms that drive the most severe winds in complex terrain. This award provides funding for the analysis and numerical modeling of data from the Sundowner Wind Experiment in the coastal Santa Barbara region of California. Sundowner winds are a specific type of downslope windstorm in the Santa Barbara area and they get their name from the tendency of the winds to strengthen into the evening and overnight hours. The research team plans a multi-faceted approach to provide societal benefits from this project, including working with the local National Weather Service office and Santa Barbara County Fire Department. Students will be involved with the project and outreach will be conducted at K-12 and community colleges in California and Virginia.The overarching goal of this project is to advance the understanding of interactions between downslope windstorms and upstream/downstream atmospheric boundary layer characteristics in coastal mountains by combining observations and numerical simulations. The Sundowner Winds Experiment (SWEX) was conducted from April 1 to May 15, 2022, in the coastal topography surrounding Santa Barbara, CA. Sundowner winds are a dry and gusty downslope wind on the southern facing slope of the Santa Ynez Mountains that can be associated with critical fire weather conditions. This project will use SWEX datasets and perform numerical simulations using the Weather Research and Forecasting model (WRF-km, 1.25km grid spacing) and Large Eddy Simulations (LES, 50m grid spacing) to improve the understanding of mechanisms associated with lee slope jets and near-surface wind variability. The research team will also investigate biases in WRF-km simulations. Three main objectives are targeted:1) Identify mechanisms responsible for the spatiotemporal variability of lee slope wind structure during Sundowners and quiescent periods using SWEX observations.2) Examine the skill of WRF-km in representing lee slope wind structure and identify relevant processes contributing to model biases.3) Investigate the performance of LES at 50m grid spacing in representing lee slope wind structure, and the contribution of turbulent processes to biases in simulated surface winds.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

沿海地形的下坡风暴导致许多严重的野外大火。 导致暴风雨的总体条件是众所周知的，但是由于缺乏对驱动复杂地形中最严重风的小规模机制的了解，因此很难预测风的时间和严重性。 该奖项为加利福尼亚州沿海圣塔芭芭拉地区的Sundowner Wind实验的数据分析和数值建模提供了资金。 日落风是圣塔芭芭拉（Santa Barbara）地区的一种特定类型的下坡风风暴，他们的名字从风的趋势中得名为傍晚和一夜之间。 研究小组计划采用多方面的方法来从该项目中提供社会利益，包括与当地国家气象服务办公室和圣塔芭芭拉县消防局合作。 学生将参与该项目，外展活动将在K-12和加利福尼亚州和弗吉尼亚州的社区大学进行。该项目的总体目标是通过结合观测和数字模拟来促进沿海山脉中沿海山脉和上游/下游大气边界层特征的了解。 日落风实验（SWEX）于2022年4月1日至2022年5月15日在加利福尼亚州圣塔芭芭拉的沿海地形进行。 日落风是圣伊内斯山脉南部斜坡上的干燥而阵风的下坡风，可能与关键的火灾天气有关。 该项目将使用SWEX数据集并使用天气研究和预测模型（WRF-KM，1.25公里网格间距）和大型涡流模拟（LES，50m网格间距）进行数值模拟，以提高对与Lee Slope Jets和近距离风变的机制的理解。 研究团队还将调查WRF-KM模拟中的偏见。 针对三个主要目标：1）确定使用SWEX观察期间Lee Slope风结构和静止期间的时空变化的机制。2）检查WRF-KM在代表Lee Slope风结构中的技能该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛的影响评论标准来评估的，这是对模拟地面风的偏见的过程。