Abstract Vegetation growth and physiological functioning, including carbon uptake and transpiration, can be strongly affected by drought. During water-limited conditions, urban vegetation may be limited in its ability to provide ecosystem services, such as shading and evaporative cooling. While there has been extensive research on drought response in natural vegetation and agricultural systems using remote sensing, drought impacts on urban vegetation have remained understudied. With >50% of people worldwide living in cities and the increased potential for future droughts, it is important to understand how urban vegetation will respond and to evaluate potential impacts. Here, we used repeat flights of NASA airborne imaging spectroscopy (AVIRIS and AVIRIS-NG) to quantify the responses of common urban tree species and turfgrass in downtown Santa Barbara, California, USA to the 2012–2016 California drought. The effects of the drought on vegetation were quantified using several spectral indicators: fractional cover from multiple endmember spectral mixture analysis (MESMA), vegetation indices, and continuum removed absorption features. We used existing tree crown object polygons that were classified to species and had associated estimates of pre-drought leaf area index and biomass. We also included polygons of turfgrass parks and recreational fields. All tree species and turfgrass had four or more spectral indicators with significantly lower mean values (p 0.4), suggesting co-occuring adjustments of greenness, water content, and plant pigments.

中文翻译：

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使用机载成像光谱技术对城市树木和草坪草的干旱响应

摘要 干旱会严重影响植被生长和生理功能，包括碳吸收和蒸腾作用。在缺水条件下，城市植被提供生态系统服务的能力可能会受到限制，例如遮荫和蒸发冷却。虽然使用遥感对自然植被和农业系统的干旱响应进行了广泛的研究，但干旱对城市植被的影响仍未得到充分研究。由于全球超过 50% 的人居住在城市，而且未来干旱的可能性越来越大，因此了解城市植被将如何响应并评估潜在影响非常重要。这里，我们使用 NASA 机载成像光谱（AVIRIS 和 AVIRIS-NG）的重复飞行来量化美国加利福尼亚州圣巴巴拉市中心常见城市树种和草坪草对 2012-2016 年加利福尼亚干旱的响应。干旱对植被的影响使用几个光谱指标进行量化：来自多端元光谱混合分析 (MESMA) 的覆盖率、植被指数和连续谱去除吸收特征。我们使用了现有的树冠对象多边形，这些多边形被分类为物种，并具有对干旱前叶面积指数和生物量的相关估计。我们还包括草坪公园和休闲场地的多边形。所有树种和草坪草都有四个或更多光谱指标，平均值显着较低 (p 0.4)，表明同时发生了绿度调整，