Abstract The Albany Thicket (AT) biome contains outstanding global biodiversity as well as the potential to achieve carbon credits associated with water-efficient Crasslucean acid metabolism (CAM). Understanding the water fluxes in the AT is crucial to determining carbon (C) sequestration rates and water-use efficiency. Despite large variation in water fluxes across the AT, only a few studies have been conducted in this region with their results validated against short periods of observed data. This study aims to evaluate three models of water fluxes over AT against data from an eddy covariance (EC) system active from October 2015 to May 2018. ET was modelled using the BioGeoChemistry Management (BGC-MAN) model, a biophysical model (Penman-Monteith-Leuning (PML)) and a remotely-sensed product (MOD16), and their results compared with that from the EC system. More than three decades of rainfall data from Climate Hazards Group InfraRed Precipitation with Station Data (CHIRPS) was used to assess some rainfall characteristics of the region. The mean annual rainfall is 404 mm and mean monthly rainfall ranges from 16.0–50.7 mm, with minima likely to occur in winter period (between May and July) and monthly maxima in the summer period (between October and March). Among the three hydrological years in this study, total ET for 2016-2017 exceeded rainfall received by about 7% which shows that AT is likely to be supported by groundwater at some point but this requires further investigations. Generally, the three models applied in this study performed reasonably well when compared with the measured ET. The cumulative ET from BGC-MAN was slightly higher than that from EC by 16% and 8% in 2015-2016 and 2017-2018 hydrological years respectively while PML was slightly lower by 3% and 17% in 2016-2017 and 2017-2018; additionally, MODIS was slightly lower by 14% and 7% in 2016-2017 and 2017-2018, respectively. However, the correlation between the ET from EC and simulated ET from the three models was significant at p

中文翻译：

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用于确定南非东开普省奥尔巴尼丛林水通量的三种模型的比较

摘要 奥尔巴尼灌木丛 (AT) 生物群落包含出色的全球生物多样性以及实现与节水的景天酸代谢 (CAM) 相关的碳信用额的潜力。了解 AT 中的水通量对于确定碳 (C) 封存率和用水效率至关重要。尽管整个 AT 的水通量变化很大，但在该地区仅进行了少数研究，其结果针对短期观察数据进行了验证。本研究旨在根据 2015 年 10 月至 2018 年 5 月期间活跃的涡流协方差 (EC) 系统的数据评估 AT 上的三个水通量模型。 ET 使用生物地球化学管理 (BGC-MAN) 模型、生物物理模型 (Penman- Monteith-Leuning (PML)) 和遥感产品 (MOD16)，并将他们的结果与 EC 系统的结果进行比较。来自气候灾害组红外降水与站点数据 (CHIRPS) 的三十多年的降雨数据用于评估该地区的一些降雨特征。年平均降雨量为 404 毫米，月平均降雨量为 16.0-50.7 毫米，最小值可能出现在冬季（5 月和 7 月之间）和夏季（10 月和 3 月之间）月最大值。在本研究的三个水文年中，2016-2017 年的总 ET 超过接收的降雨量约 7%，这表明 AT 可能在某个时候受到地下水的支持，但这需要进一步调查。通常，与测量的 ET 相比，本研究中应用的三个模型表现相当不错。BGC-MAN的累积ET在2015-2016和2017-2018水文年分别比EC略高16%和8%，而PML在2016-2017和2017-2018年分别略低3%和17% ; 此外，2016-2017 年和 2017-2018 年 MODIS 分别小幅下降 14% 和 7%。然而，来自 EC 的 ET 和来自三个模型的模拟 ET 之间的相关性在 p