Dynamical Effects of Solar Ultraviolet Variations in the Lower Stratosphere

平流层下部太阳紫外线变化的动力学效应

• 批准号: 0424840
• 负责人: Lon Hood
• 金额: $ 22.62万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0424840&HistoricalAwards=false
• 关键词: Dynamical; Effects; Solar; Ultraviolet; Variations

This project is designed to test mechanisms for transmitting the direct upper stratospheric effects of solar ultraviolet variations to lower levels in the tropical and subtropical atmosphere, using a combination of observational and mechanistic modeling techniques. The results of previous research showing that the dynamical effects of solar ultraviolet variations in the tropical lower stratosphere may occur through a modulation of the Brewer-Dobson circulation will be investigated in greater detail to establish the presence or absence of solar-induced decadal variations in extratropical wave forcing. Using accurate ozone profile data and Eliassen-Palm planetary wave flux divergences, the existence of decadal variations in wave forcing and tropical upwelling rates will also be investigated This project with also extend existing studies showing that the occurrence and/or timing of stratospheric sudden warmings at high winter latitudes can be influenced by upper stratospheric zonal winds, which are in turn perturbed by the direct effects of solar ultraviolet variations on ozone photochemistry and radiative heating. Specifically, evidence will be sought to determine if the observed thermal responses to 27-day solar ultraviolet variations in the tropical tropopause region are caused by solar ultra-violet-induced changes in the occurrence of sudden stratospheric warmings. This should enable identification of dipole and quadrupole structures of the response, which would be indicative of the dynamical effects of extratropical warmings and wave absorption events. Successful identification of the cause(s) of these variations will impose significant new constraints on climate models so that the solar forcing contribution to climate change can be more accurately estimated. The project will facilitate the training of one graduate research assistant.

该项目旨在测试太阳紫外线变化对上层平流层的直接影响传递到热带和亚热带大气下层的机制，同时使用观测和机制建模技术。以前的研究结果表明，太阳紫外线变化对热带平流层下部的动力学影响可能是通过调制布鲁尔-多布森环流而产生的，将对这些结果进行更详细的研究，以确定太阳引起的对流层外波强迫的十年变化是否存在。利用精确的臭氧廓线数据和Eliassen-Palm行星波通量散度，还将研究波强迫和热带上升流速率的十年变化。而臭氧层又受到太阳紫外线变化对臭氧光化学和辐射加热的直接影响的干扰。具体而言，将寻求证据，以确定所观察到的热带对流层顶区域27天太阳紫外线变化的热响应是否是由太阳紫外线引起的平流层突然变暖的变化引起的。这应该能够识别偶极和四极结构的响应，这将是指示的动力学效应的外辐射变暖和波吸收事件。成功地识别这些变化的原因将对气候模型施加重要的新约束，从而可以更准确地估计太阳强迫对气候变化的贡献。该项目将有助于培训一名研究生助理。