Untangling the importance of dynamic and thermodynamic drivers for wet and dry spells across the Tropical Andes
Untangling the importance of dynamic and thermodynamic drivers for wet and dry spells across the Tropical Andes
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阐明热带安第斯山脉干湿期动态和热力学驱动因素的重要性
DOI：
10.1088/1748-9326/acb72b
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发表时间：
2023
影响因子：
6.7
通讯作者：
Klein C
中科院分区：
文献类型：
--
作者：
Klein C
安第斯山脉的植被和农业取决于南美季风期间的降雨模式。然而，我们对动力(高层风环流)与热力(亚马逊盆地湿度)驱动因素对安第斯山脉降雨的重要性的理解仍然有限。这项研究考察了这些驱动因素对热带安第斯山脉3-7天干湿天气的影响，并评估了由此对植被的影响。利用1985-2018年的再分析和遥感资料，我们发现动力和热力驱动因素在决定降雨型方面都起到了作用。值得注意的是，我们发现高空风是整个热带安第斯山脉降雨量的重要驱动因素，但不是亚马逊低地的降雨量，这表明地形在这种关系中起着至关重要的作用。从热力学的角度来看，我们发现湿天气条件与沿安第斯山脉东部山脚的水汽增加有关，伴随着一股加强的南美低空急流，所有被考虑的地区的水汽通过地形和对流上升到安第斯山脉。我们的结果表明，虽然亚马逊流域湿度的变化在与三天周期相关的日时间尺度上主导着降水变化，但高层动力在5-7天周期的天气时间尺度上起着更重要的作用。考虑到对地面的影响，我们发现在半干旱的安第斯山脉只有5-7天的时间对植被有长期影响。我们的研究强调，在估计热带安第斯山脉的降雨量变化时，包括在未来气候预测的背景下，需要考虑动力和热力学驱动因素。
Andean vegetation and agriculture depend on the patterns of rainfall during the South American monsoon. However, our understanding on the importance of dynamic (upper-level wind circulation) as compared to thermodynamic (Amazon basin moisture) drivers for Andes rainfall remains limited. This study examines the effect of these drivers on 3–7 day wet and dry spells across the Tropical Andes and assesses resulting impacts on vegetation. Using reanalysis and remote sensing data from 1985–2018, we find that both dynamic and thermodynamic drivers play a role in determining the rainfall patterns. Notably, we show that the upper-level wind is an important driver of rainfall across the entire Tropical Andes mountain range, but not in the Amazon lowlands, suggesting a crucial role of topography in this relationship. From thermodynamic perspective, we find wet spell conditions to be associated with increased moisture along the Andes' eastern foothills accompanied by a strengthened South American low-level jet, with moisture lifted into the Andes via topography and convection for all considered regions. Our results suggest that while changes in Amazon basin moisture dominate rainfall changes on daily time scales associated with three day spells, upper-level dynamics play a more important role on the synoptic time scale of 5–7 day spells. Considering impacts on the ground, we find that only 5–7 day spells in the semi-arid Andes have a prolonged effect on vegetation. Our study emphasizes the need to consider both dynamic and thermodynamic drivers when estimating rainfall changes in the Tropical Andes, including in the context of future climate projections.
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影响因子：
7.3
作者：
Gurgiser, Wolfgang;Juen, Irmgard;Kaser, Georg
通讯作者：
Kaser, Georg
带有站点的气候危害红外降水 - 一种新的环境记录，用于监测极端。
影响因子：
9.8
作者：
Funk C;Peterson P;Landsfeld M;Pedreros D;Verdin J;Shukla S;Husak G;Rowland J;Harrison L;Hoell A;Michaelsen J
通讯作者：
Michaelsen J
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影响因子：
2.9
作者：
Trachte
通讯作者：
Trachte
南美低空急流实验（SALLJEX）观测季期间南美高原的湿度变化
影响因子：
--
作者：
M. Falvey;R. Garreaud
通讯作者：
R. Garreaud
影响因子：
11.6
作者：
Kimm, Hyungsuk;Guan, Kaiyu;Wu, Genghong
通讯作者：
Wu, Genghong