Seasonal and Morphological Controls on Nitrate Retention in Arctic Deltas
Seasonal and Morphological Controls on Nitrate Retention in Arctic Deltas
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DOI：
10.1029/2022gl102201
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发表时间：
2023-04
影响因子：
5.2
通讯作者：
D. Knights;A. Piliouras;J. Schwenk;J. Hariharan;Christopher J. Russoniello
中科院分区：
文献类型：
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作者：
D. Knights;A. Piliouras;J. Schwenk;J. Hariharan;Christopher J. Russoniello
对北冰洋硝酸盐负荷量的估计受到三角洲内缺乏实地观测的限制，部分原因是后勤方面的限制。为了克服这一限制，我们使用遥感框架来估计北极三角洲中硝酸盐的保留量。我们通过在网络尺度上耦合五个主要北极三角洲的水文和生物地球化学过程模型来实现这一点。用三角洲河道的二值掩模来模拟网络中的水流方向和流量。使用历史和季节观测对模型进行了参数化。模拟硝酸盐滞留在进水负荷的2.9%到15%之间。留存率在冬季最大，但在春季条件下最小，因为增加的排泄量会将大量硝酸盐输出到海岸。在未来的气候情景下，留存率将下降∼1%-10%。北极三角洲对进入北冰洋的硝酸盐的大小有重要影响，将加工过程纳入三角洲可以改善通量估计。
Estimates of nitrate loading to the Arctic Ocean are limited by the lack of field observations within deltas partly due to logistical constraints. To overcome this limitation, we use a remote sensing framework to estimate retention of nitrate in Arctic deltas. We achieve this by coupling hydrological and biogeochemical process models at the network scale for five major Arctic deltas. Binary masks of delta channels were used to simulate flow direction and magnitude through networks. Models were parameterized using historical and seasonal observations. Simulated nitrate retention ranged from 2.9% to 15% of the incoming load. Retention rates were largest during winter but smallest during spring conditions when increased discharges export large nitrate masses to the coast. Under future climate scenarios, retention rates fall by ∼1%–10%. Arctic deltas have an important effect on the magnitude of nitrate entering Arctic seas and the inclusion of processing in deltas can improve flux estimates.