Quantifying Drought Propagation from Soil Moisture to Vegetation Dynamics Using a Newly Developed Ecohydrological Land Reanalysis
Quantifying Drought Propagation from Soil Moisture to Vegetation Dynamics Using a Newly Developed Ecohydrological Land Reanalysis
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DOI：
10.3390/rs10081197
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发表时间：
2018-07
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影响因子：
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通讯作者：
Y. Sawada
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作者：
Y. Sawada
尽管土壤水分和植被动态之间的相互作用对理解干旱的复杂性质很重要，但很少有土地再分析明确模拟植被的生长和衰老。在这项研究中，我提供了一种新的土地再分析，通过逐次同化卫星微波亮度温度观测到陆地表面模式（LSM），明确模拟了地下土壤湿度与植被动态之间的相互作用。同化卫星微波亮度温度观测数据提高了LSM同时模拟土壤湿度和叶面积指数（LAI）季节循环的能力。通过分析这一新的陆地再分析模拟的土壤湿度和LAI，我确定了在LAI季节峰值的气候年数上显著损害LAI的干旱事件，并量化了全球无雪地区从土壤湿度到LAI的干旱传播。平均而言，浅土层（0 ~ 0.45 m）土壤水分在LAI季节气候日数高峰前迅速从干旱状态恢复，而较深土层（1.05 ~ 2.05 m）土壤水分和LAI在LAI季节气候日数高峰后约100 d从干旱状态恢复。
Despite the importance of the interaction between soil moisture and vegetation dynamics to understand the complex nature of drought, few land reanalyses explicitly simulate vegetation growth and senescence. In this study, I provide a new land reanalysis which explicitly simulates the interaction between sub-surface soil moisture and vegetation dynamics by the sequential assimilation of satellite microwave brightness temperature observations into a land surface model (LSM). Assimilating satellite microwave brightness temperature observations improves the skill of a LSM to simultaneously simulate soil moisture and the seasonal cycle of leaf area index (LAI). By analyzing soil moisture and LAI simulated by this new land reanalysis, I identify the drought events which significantly damage LAI on the climatological day-of-year of the LAI’s seasonal peak and quantify drought propagation from soil moisture to LAI in the global snow-free region. On average, soil moisture in the shallow soil layers (0–0.45 m) quickly recovers from the drought condition before the climatological day-of-year of the LAI’s seasonal peak while soil moisture in the deeper soil layer (1.05–2.05 m) and LAI recover from the drought condition approximately 100 days after the climatological day-of-year of the LAI’s seasonal peak.