The Diurnal Dynamics of Gross Primary Productivity Using Observations From the Advanced Baseline Imager on the Geostationary Operational Environmental Satellite‐R Series at an Oak Savanna Ecosystem
The Diurnal Dynamics of Gross Primary Productivity Using Observations From the Advanced Baseline Imager on the Geostationary Operational Environmental Satellite‐R Series at an Oak Savanna Ecosystem
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DOI：
10.1029/2021jg006701
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发表时间：
2022-03
期刊：
影响因子：
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通讯作者：
A. M. Khan;P. Stoy;J. Joiner;D. Baldocchi;J. Verfaillie;M. Chen;J. Otkin
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文献类型：
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作者：
A. M. Khan;P. Stoy;J. Joiner;D. Baldocchi;J. Verfaillie;M. Chen;J. Otkin
总初级生产力（GPP）是全球碳循环中最大的通量，基于卫星的 GPP 估算长期以来一直被用来研究 GPP 的趋势和年际变化。随着最近对地球静止卫星的更新，我们现在可以在与极轨卫星相当的空间分辨率和与涡协方差（EC）塔站相当的时间频率下探索 GPP 的日变化。我们使用对地静止运行环境卫星 R 系列 (GOES-R) 上的高级基线成像仪的观测结果来测试次日卫星数据捕获美国加利福尼亚州橡树稀树草原 EC 站点的 GPP 昼夜变化的能力，该站点受到季节性土壤湿度下降的影响。我们比较了三种估计 GPP 的方法：(a) 光利用效率模型，(b) 植被近红外反射率与光合有效辐射 (LIN-NIRvP) 的乘积与 EC 塔 GPP 之间的线性关系，以及 (c) NIRvP 与 EC GPP 之间的光响应曲线 (LRC-NIRvP)。 LRC-NIRvP 在冬季（2 µmol CO2 m−2 s−1）、春季（2.51 µmol CO2 m−2 s−1）、夏季（1.43 µmol CO2 m−2 s−1）和秋季（1.35 µmol CO2 m−2 s−1）实现了最低平均绝对误差。在干燥的夏季，生态系统经历了与入射太阳辐射峰值相关的每日峰值 GPP 向早晨的最大转变。 LRC-NIRvP 和光利用效率模型与夏季每日 GPP 峰值向早晨移动的这些模式一致。我们的结果可以帮助对地球静止卫星进行 GPP 的日间估计，这些卫星对白天波动的环境条件很敏感。
Gross primary productivity (GPP) is the largest flux in the global carbon cycle and satellite‐based GPP estimates have long been used to study the trends and interannual variability of GPP. With recent updates to geostationary satellites, we can now explore the diurnal variability of GPP at a comparable spatial resolution to polar‐orbiting satellites and at temporal frequencies comparable to eddy covariance (EC) tower sites. We used observations from the Advanced Baseline Imager on the Geostationary Operational Environmental Satellite‐R series (GOES‐R) to test the ability of subdaily satellite data to capture the shifts in the diurnal course of GPP at an oak savanna EC site in California, USA that is subject to seasonal soil moisture declines. We compared three methods to estimate GPP: (a) a light‐use efficiency model, (b) a linear relationship between the product of near‐infrared reflectance of vegetation and photosynthetically active radiation (LIN‐NIRvP) and EC tower GPP, and (c) a light response curve (LRC‐NIRvP) between NIRvP and EC GPP. The LRC‐NIRvP achieved the lowest mean absolute error for winter (2 µmol CO2 m−2 s−1), spring (2.51 µmol CO2 m−2 s−1), summer (1.43 µmol CO2 m−2 s−1), and fall (1.35 µmol CO2 m−2 s−1). The ecosystem experienced the largest shift in daily peak GPP in relation to the peak of incoming solar radiation toward the morning hours during the dry summers. The LRC‐NIRvP and the light‐use efficiency model were in agreement with these patterns of a shift in peak daily GPP toward the morning hours during summer. Our results can help develop diurnal estimates of GPP from geostationary satellites that are sensitive to fluctuating environmental conditions during the day.