Isolating the Observed Influence of Vegetation Variability on the Climate of La Plata River Basin
Isolating the Observed Influence of Vegetation Variability on the Climate of La Plata River Basin
复制标题
分离观测到的植被变化对拉普拉塔河流域气候的影响
作者：
D. Chug;F. Dominguez
这项工作旨在利用观测记录来分离和量化缓慢变化的植被变异对拉普拉塔盆地（LPB）气候的当地和远程生物地球物理影响。过去的研究表明，该季节 LPB 存在强烈的陆地-大气耦合。该分析使用了美国宇航局制作地球系统数据记录用于研究环境（MEaSUREs）植被指数和物候数据集的改良增强植被指数（EVI2）的34年记录（1981-2014年）以及来自全球清单建模和制图研究的第三代标准化差异植被指数（NDVI）。使用 LPB 上的经验正交函数/主成分分析来评估植被指数在空间和时间上的变化的主要模式。南方春季的主导模态是植被偶极子，盆地东北部（西南部）植被指数呈绿化（褐化）或正（负）异常。使用逐步广义平衡反馈评估（SGEFA），可以分离出植被变异对大气的影响。南方春季LPB植被变化的主导模式与西南LPB气温升高和盆地中部和南部降水增加有关。提出了一种机制，解释了东北部LPB由于绿化而导致潜热通量增加和温度降低，以及西南LPB由于褐变而导致感热通量增加、温度升高和表面压力降低的机制。对这种诱发压力梯度的地转响应导致富含水分的风向北异常增强，水分更深地渗透到LPB中，并导致盆地中部和南部降水增加。
This work aims to isolate and quantify the local and remote biogeophysical influences of slowly varying vegetation variability on the climate of La Plata basin (LPB) in the austral spring season (September–November) using observational records. Past studies have shown strong land–atmosphere coupling in LPB during this season. The analysis uses a 34-yr record (1981–2014) of the modified enhanced vegetation index (EVI2) from the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) Vegetation Index and Phenology dataset and the third-generation normalized difference vegetation index (NDVI) from Global Inventory Modeling and Mapping Studies. The dominant patterns of vegetation index variability in space and time are assessed using empirical orthogonal function/principal component analysis over the LPB. The dominant mode in the austral spring is a vegetation dipole, with greening (browning) or positive (negative) vegetation index anomalies in the northeastern (southwestern) part of the basin. Using the stepwise generalized equilibrium feedback assessment (SGEFA), the effect of the vegetation variability on the atmosphere is then isolated. The dominant mode of LPB vegetation variability in austral spring is related to warmer temperatures in the southwest LPB and enhanced precipitation over the central and southern parts of the basin. A mechanism is proposed for the increase in latent heat flux and cooler temperatures in the northeastern LPB due to greening, and the increase in sensible heat flux, warmer temperatures, and decrease in surface pressure in southwestern LPB due to browning. The geostrophic response to this induced pressure gradient leads to anomalous northerly enhancement of moisture-laden winds, deeper penetration of moisture into LPB, and increased precipitation over the central and southern parts of the basin.
影响因子：
4.4
作者：
Knist, Sebastian;Goergen, Klaus;Simmer, Clemens
通讯作者：
Simmer, Clemens