Collaborative Research: Sundowner Winds EXperiment (SWEX) in Santa Barbara, California

合作研究：加利福尼亚州圣巴巴拉的日落风实验 (SWEX)

• 批准号: 1921596
• 负责人: Zhien Wang
• 金额: $ 13.68万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1921596&HistoricalAwards=false
• 关键词: Collaborative; Research; Sundowner; Winds; EXperiment

Wildfires are among the greatest natural hazards in the Western U.S. and other parts of the world. The numerous tragic events in recent years in California have exposed the great vulnerability of the population to wildfires and the critical need to improve understanding and enhance predictability of windstorms in complex terrain. Coastal Santa Barbara County (SB), with a population exceeding 130,000 inhabitants, is among the most exposed communities to wildfire hazards in southern California. The Santa Ynez Mountains rise abruptly from coastal SB separating the Pacific Ocean on its south face from the Santa Ynez Valley on its north face. Downslope, dry and gusty windstorms are frequently observed on the southern-facing slopes of the Santa Ynez Mountains. These winds typically intensify around sunset and throughout the night, and are known as "Sundowner winds" or "Sundowners". They are considered the most significant fire-weather regime in coastal SB and pose hazardous conditions to aviation. They have enhanced the severity of all major wildfires affecting the SB coastal population. Therefore, improved weather warnings and forecast lead time, including spatiotemporal specificity of where winds will be strongest, are critical to increase resilience to wildfires. Sundowners exhibit large spatiotemporal variability and are driven by unique complex mechanisms. The Sundowner Winds Experiment (SWEX) will investigate these unique aspects of Sundowners to advance the understanding and predictability of these winds, while providing rich data sets for developing new theories of downslope windstorms in coastal environments with similar geographic and climatic characteristics. This will be accomplished with strategic meteorological observations of the atmospheric processes hypothesized to modulate Sundowner winds intensity and spatial variability. These results will significantly contribute to improve the predictability of windstorms in complex terrain in coastal environments, with significant impacts to large communities living in fire prone areas. The project will provide key outreach materials for dissemination to government agencies and the media and will educate the public about fire weather and natural disasters. Moreover, the project will support the development of new educational courses, and the training of undergraduate and graduate students, including minorities, in six universities in the U.S. Sundowners spatiotemporal characteristics are controlled by complex interactions between atmospheric processes occurring upstream, in the Santa Ynez Valley and San Rafael Mountains, and downstream due to the influence of a cool and stable marine boundary layer. The SWEX campaign is designed to enhance spatial measurements to resolve local circulations and vertical profiles from the boundary layer to the mid-troposphere, and from the SB channel to the Santa Ynez Valley. These observations will be used to test hypotheses concerning the mechanisms controlling Sundowner winds, evaluate mesoscale simulations and improve lead time forecasts of Sundowners. More specifically, the multi-sensor platforms and aircraft will be utilized to investigate how the structure and dynamics of the marine and continental Boundary Layers (BL) influence mountain flows during Sundowners and undisturbed periods, including intensity, timing and geographic characteristics of downslope winds, temperatures and humidity. These measurements will enable to examine underlying mechanisms relating high amplitude mountain waves, critical layers, and surface wind intensity leeward of the Santa Ynez Mountains. These observations will be utilized to investigate how variations in BL structure and tropospheric stability control mountain wave flows and the lee-slope jet, and the importance of these mechanisms for the predictability of Sundowner winds. SWEX brings cutting-edge science, the state-of-art facilities at National Center for Atmospheric Research and multiple instrumental platforms to bear on this important problem. It will build linkages with those responsible for predictions and fire response in a region that is representative of many areas with similar vulnerabilities. SWEX will improve the capability of the National Weather Service to forecast weather hazards in the Los Angeles area, specifically in coastal SB. Thus this project has substantial broader impacts.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.

野火是美国西部和世界其他地区最大的自然灾害之一。近年来，加利福尼亚州的众多悲剧事件暴露了人口对野火的巨大脆弱性，以及提高复杂地形中风暴的理解和可预测性的迫切需求。人口超过130,000居民的沿海圣塔芭芭拉县（SB）是南加州野火危害的最暴露社区之一。圣伊内斯山脉从沿海SB突然上升，将其南面的太平洋与北面的圣塔伊兹山谷分开。在圣伊内斯山脉的南部斜坡上经常观察到下坡，干和狂风的风暴。这些风通常在日落和整夜都在加剧，被称为“日落风”或“日落”。它们被认为是沿海SB中最重要的火山风格，并对航空构成危险条件。他们加强了影响SB沿海人口的所有主要野火的严重性。因此，改善的天气警告和预测提前时间，包括风将最强的时空特异性，对于增加对野火的弹性至关重要。日落者表现出较大的时空变异性，并由独特的复杂机制驱动。日落风实验（SWEX）将调查日落者的这些独特方面，以提高这些风的理解和可预测性，同时为在具有相似地理和气候特征的沿海环境中开发新的下坡风风暴的新理论。这将通过对被认为调节日落风强度和空间变化的大气过程的战略气象观察来完成。这些结果将极大地有助于提高沿海环境中复杂地形中暴风雨的可预测性，并对居住在火灾的大型社区产生重大影响。该项目将为政府机构和媒体提供关键的外展材料，并将向公众提供有关火灾天气和自然灾害的教育。 Moreover, the project will support the development of new educational courses, and the training of undergraduate and graduate students, including minorities, in six universities in the U.S. Sundowners spatiotemporal characteristics are controlled by complex interactions between atmospheric processes occurring upstream, in the Santa Ynez Valley and San Rafael Mountains, and downstream due to the influence of a cool and stable marine boundary layer. SWEX活动旨在增强空间测量，以解决从边界层到对流层中部以及从SB通道到圣伊内斯山谷的局部循环和垂直轮廓。这些观察结果将用于测试有关控制日落风，评估中尺度模拟并改善日落者的交付时间预测的机制的假设。更具体地说，将利用多传感器平台和飞机来研究海洋和大陆边界层（BL）的结构和动力学如何影响日落者期间的山流以及不受干扰的时期，包括下坡风，温度，温度，温度和湿度的强度，时机和地理特征。这些测量值将能够检查与圣伊内兹山脉的高振幅山波，临界层和表面风强度相关的基本机制。这些观察结果将用于研究BL结构和对流层稳定性控制山波流和Lee-Slope Jet的变化，以及这些机制对于日落风的可预测性的重要性。 Swex带来了最先进的科学，这是国家大气研究中心的最先进设施，以及多个工具平台，以解决这一重要问题。它将与负责预测和火灾反应的人建立联系，该地区代表许多具有相似脆弱性的领域。 SWEX将提高国家气象局在洛杉矶地区，特别是在沿海SB中的预测天气危害的能力。因此，该项目具有更广泛的影响。该奖项反映了NSF的法定任务，并被认为是使用基金会的知识分子优点和更广泛影响审查标准的评估值得支持的。