Understanding Future Changes in Midlatitude Orographic Precipitation

了解中纬度地形降水的未来变化

• 批准号: 2024212
• 负责人: Nicholas Siler
• 金额: $ 43.18万
• 依托单位: Oregon State University
• 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: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2024212&HistoricalAwards=false
• 关键词: Understanding; Future; Changes; Midlatitude; Orographic

Orographic precipitation refers to rain and snow that develops due to air that is forced upward over mountainous terrain. Orographic precipitation depends on numerous factors, and how those factors change in future climate states will impact the climatology of the amount and location of precipitation in relation to the terrain. One common result from climate modeling is that precipitation on the downslope side of mountains will increase, which would have a large impact on water resources and potential flooding. This study will analyze an existing high-resolution numerical simulation and perform new simulations to determine the physical mechanisms behind these changes. The work has direct impact on farmers, water-resource managers, and other stakeholders in the Western US, and the researchers will engage with this group through the participation in the Climate Impacts Research Consortium. Multiple graduate students will also be trained.The research team will conduct a numerical modeling study to better understand the potential changes in orographic precipitation in future climate states. Prior modeling has provided evidence that precipitation will increase in the “rain shadow” areas on the lee side of mountainous terrain. The research team will analyze existing output from a 35-year high-resolution “pseudo-global warming” simulation and conduct new simulations to address the following research questions: 1) What types of storms contribute most to the pattern of precipitation change in the Cascades and Sierra Nevada? 2) What mechanisms – dynamic, thermodynamic, and/or microphysical – contribute to orographic precipitation change, and what is their relative importance? 3) How sensitive are the results to differences in model parameterizations, especially related to cloud microphysics? 4) Does the pattern and mechanisms of precipitation change in the Cascades and Sierra Nevada hold lessons for other midlatitude mountain ranges, such as the Andes or Southern Alps?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.

地形降水是指由于空气被迫向上越过山区地形而形成的雨和雪。 地形降水取决于许多因素，这些因素在未来气候状态中的变化将影响降水量和降水位置与地形的气候学关系。 气候模拟的一个常见结果是，山区下坡一侧的降水量将增加，这将对水资源和潜在的洪水产生重大影响。 这项研究将分析现有的高分辨率数值模拟，并进行新的模拟，以确定这些变化背后的物理机制。 这项工作对美国西部的农民、水资源管理者和其他利益相关者产生了直接影响，研究人员将通过参与气候影响研究联盟与这一群体接触。 研究团队将进行数值模拟研究，以更好地了解未来气候状态下地形降水的潜在变化。 先前的模拟已经提供了证据表明，在山区地形背风侧的“雨影”区域，降水量将增加。 研究小组将分析35年高分辨率“伪全球变暖”模拟的现有输出，并进行新的模拟，以解决以下研究问题：1）什么类型的风暴对喀斯喀特山脉和内华达州山脉的降水变化模式贡献最大？2)什么机制-动力学，热力学，和/或微物理-有助于地形降水变化，它们的相对重要性是什么？ 3)结果对模式参数化的差异有多敏感，特别是与云微物理学有关的？4)喀斯喀特山脉和内华达州山脉降水变化的模式和机制是否对其他中纬度山脉，如安第斯山脉或南阿尔卑斯山脉有借鉴意义？该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。

项目成果

Understanding drivers of glacier-length variability over the last millennium

了解过去千年冰川长度变化的驱动因素

• DOI: 10.5194/tc-15-1645-2021
• 发表时间: 2021
• 期刊: The Cryosphere
• 作者: Huston, Alan;Siler, Nicholas;Roe, Gerard H.;Pettit, Erin;Steiger, Nathan J.
• 通讯作者: Steiger, Nathan J.