Rain pulses followed by interstorm drying periods are the fundamental units of water input into ecosystems on subweekly time scales. It is essential to understand landscape‐scale vegetation responses on these unit time scales as they may describe sensitivity of landscape water, carbon, and energy cycles to shifts in rainfall intensity and frequency, even if the average seasonal precipitation remains unchanged. Because pulse investigations are primarily carried out in drylands, little is known about the characteristics and extent of ecosystem plant pulse responses across the broader range of climates and biomes. Using satellite‐based plant water content (from vegetation optical depth) and plant carbon uptake observations from eddy covariance towers across the continental United States climate gradient (dry to humid), we characterize large‐scale plant carbon and water uptake responses to rain pulses during spring and summer months. We find that while all ecosystems in the study region show discernable plant water content and carbon flux responses to rain pulses, drier ecosystems exhibit more frequent and longer duration responses. Unlike mesic environments, drylands show significantly different responses under varying antecedent soil moisture and pulse magnitude conditions; the largest water and carbon uptakes follow large pulses on initially wet soils. We detect soil moisture thresholds primarily in drylands, which can partly explain dryland vegetation's different responses under dry and wet conditions. We conclude that vegetation responds to individual pulses of water availability across all climates and therefore a range of ecosystems are sensitive to rainfall distributions beyond simple seasonal precipitation totals.

中文翻译：

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水分脉冲后景观植物水分含量和碳通量行为：从旱地到环境

在下周的时间尺度上，降雨脉冲和暴风雨间的干旱期是向生态系统输入水的基本单位。必须了解这些单位时间尺度上的景观尺度植被响应，因为它们可能描述了景观水，碳和能量循环对降雨强度和频率变化的敏感性，即使平均季节降水量保持不变。由于脉冲调查主要在干旱地区进行，因此人们对整个气候和生物群落范围内的生态系统植物脉冲响应的特征和程度了解甚少。使用基于卫星的植物水分含量（来自植被的光学深度）和整个美国大陆气候梯度（干燥至潮湿）的涡度协方差塔的植物碳吸收观测值，我们表征了春季和夏季月份植物对雨水脉冲的碳和水吸收响应。我们发现，虽然研究区域中的所有生态系统均显示出可识别的植物水分含量和碳通量对降雨脉冲的响应，但较干燥的生态系统却显示出更频繁，持续时间更长的响应。与干旱环境不同，旱地在变化的土壤湿度和脉冲强度条件下表现出明显不同的响应。在最初潮湿的土壤上，最大的水和碳吸收量跟随着大的脉冲运动。我们主要在干旱地区检测土壤水分阈值，这可以部分解释干旱地区在干燥和潮湿条件下的不同响应。