Department of Physical Geography and Regional Geographic Analysis, Universidad de Sevilla, 41004 Seville, Spain.
Department of Physical Geography and Regional Geographic Analysis, Universidad de Sevilla, 41004 Seville, Spain.
Sci Total Environ. 2024 Dec 1;954:176453. doi: 10.1016/j.scitotenv.2024.176453. Epub 2024 Sep 21.
Iberian Peninsula ecosystems are especially vulnerable to global warming, and variations in climate patterns may alter the wide variety of services they provide. Despite this, seasonal variations in Iberian ecosystems have been understudied. Thus, this study aims to characterise land surface phenology (LSP) patterns in the Iberian Peninsula over 21 years (2001-2021), considering three phenometrics: the start (SOS), the end (EOS), and the length of the growing season (LOS). These were estimated from 8-day image composites of EVI2 (Two-band Enhanced Vegetation Index), derived from the surface reflectance product MOD09Q1 at a 250-metre spatial resolution. Phenometrics and in-situ human phenological observations of plant phenophases were also compared. Pearson's correlation coefficient, p-value, and absolute differences between paired phenometrics and phenophases were calculated to quantify uncertainty between both phenological approaches. Generally, SOS and EOS dates were later in the Alpine and Atlantic biogeographic regions. SOS occurred in March-April and EOS between October-December. Natural vegetation land cover types had similar phenological dynamics, with SOS occurring between late winter and spring and EOS between autumn and early winter. However, phenometric dates were earlier in Mediterranean savannas, grasslands, and scrublands. Atlantic evergreen broadleaf vegetation showed the strongest correlations between SOS and the first (r = 0.96) and second (r = 0.68) leaf unfolding. In contrast, Mediterranean evergreen broadleaf vegetation had unclear correlations. Atlantic deciduous broadleaf vegetation showed a moderate correlation between SOS and first (r = 0.52) and second (r = 0.57) leaf unfolding. The correlation between SOS and the first (r = 0.14) and second (r = 0.13) leaf unfolding was weaker for Mediterranean deciduous broadleaf vegetation. EOS and autumn phenophases generally showed unclear consistency. Higher spatial resolution satellite data may improve the consistency between EOS and autumn phenophases in Iberian ecosystems, as well as between SOS and spring phenophases in heterogeneous Mediterranean ecosystems.
伊比利亚半岛的生态系统特别容易受到全球变暖的影响，气候模式的变化可能会改变它们提供的各种服务。尽管如此，伊比利亚生态系统的季节性变化研究还不够充分。因此，本研究旨在 21 年间（2001-2021 年）描述伊比利亚半岛的土地表面物候（LSP）模式，考虑到三个物候指标：开始期（SOS）、结束期（EOS）和生长季长度（LOS）。这些指标是根据 MOD09Q1 表面反射率产品生成的 8 天 EVI2（双波段增强植被指数）图像组合估算得出的，空间分辨率为 250 米。还比较了物候指标和植物物候阶段的现场人类观测。计算了 Pearson 相关系数、p 值和成对物候指标和物候阶段之间的绝对差异，以量化两种物候方法之间的不确定性。通常，阿尔卑斯和大西洋生物地理区域的 SOS 和 EOS 日期较晚。SOS 发生在 3-4 月，EOS 在 10-12 月之间。自然植被土地覆盖类型具有相似的物候动态，SOS 发生在冬季末到春季，EOS 发生在秋季到初冬。然而，地中海稀树草原、草原和灌丛的物候日期更早。大西洋常绿阔叶植被 SOS 与第一（r=0.96）和第二（r=0.68）叶展开之间具有最强的相关性。相比之下，地中海常绿阔叶植被的相关性不明确。大西洋落叶阔叶植被 SOS 与第一（r=0.52）和第二（r=0.57）叶展开之间呈中度相关性。地中海落叶阔叶植被 SOS 与第一（r=0.14）和第二（r=0.13）叶展开之间的相关性较弱。EOS 和秋季物候阶段通常一致性不明确。高空间分辨率卫星数据可能会提高伊比利亚生态系统中 EOS 和秋季物候阶段之间以及地中海生态系统中 SOS 和春季物候阶段之间的一致性。
