Physically based model of the contribution of red snow algal cells to temporal changes in albedo in northwest Greenland
Physically based model of the contribution of red snow algal cells to temporal changes in albedo in northwest Greenland
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DOI：
10.5194/tc-14-2087-2020
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发表时间：
2020-06-29
期刊：
影响因子：
5.2
通讯作者：
Aoki, Teruo
中科院分区：
文献类型：
--
作者：
Onuma, Yukihiko;Takeuchi, Nozomu;Aoki, Teruo
雪和冰的表面附着力被无机杂质大大降低，如风成矿物粉尘（MD）和炭黑（BC），也被有机杂质，如生活在雪中的微生物。在本文中，我们提出了在2014年消融季节期间在格陵兰岛西北部的积雪上观察到的表面冰、雪颗粒大小、MD、BC和雪藻细胞浓度的时间变化，以及我们试图用基于物理的雪冰模型再现冰的变化。我们还试图重现无机杂质和红雪藻（雪藻）对水螅的影响。MD和红雪藻在表面雪的浓度被发现在8月初增加，而雪的粒度和BC被发现在整个消融季节没有显着变化。从7月下旬到8月上旬，地表温度下降了0.08。该模型模拟的时间序列与研究期间观察到的时间序列一致。8月上旬，红雪藻对地表浮游植物的影响不大。这可能是由于与以前在北极地区的研究报告的红雪细胞丰度（类似于10（8）个细胞L-1）相比，更小的细胞丰度（4.9 x 10（4）个细胞L-1）。用雪藻模型模拟雪中二氧化碳的浓度，直到融化季节结束，结果表明，在格陵兰西北部的积雪中，三种杂质导致的二氧化碳总减少量为0.102，而红色雪藻导致的二氧化碳减少量为0.004。最后，我们进行了情景模拟，使用雪藻模型，再加上雪藻模型，以模拟在格陵兰西北部温暖的条件下，红色的雪开花对雪藻可能产生的影响。结果表明，在温暖的条件下（表面雪温为+1.5摄氏度），红雪藻生长减少的辐射量达到0.04，相当于2014年消融季节的辐射强迫为7.5 W m（-2）。这种耦合的雪覆盖度模型有可能动态模拟雪覆盖度，包括有机和无机杂质的影响，导致在格陵兰岛的积雪的表面雪覆盖度的适当估计。
Surface albedo of snow and ice is substantially reduced by inorganic impurities, such as aeolian mineral dust (MD) and black carbon (BC), and also by organic impurities, such as microbes that live in the snow. In this paper, we present the temporal changes of surface albedo, snow grain size, MD, BC and snow algal cell concentration observed on a snowpack in northwest Greenland during the ablation season of 2014 and our attempt to reproduce the changes in albedo with a physically based snow albedo model. We also attempt to reproduce the effects of inorganic impurities and the red snow algae (Sanguina nivaloides) on albedo. Concentrations of MD and red snow algae in the surface snow were found to increase in early August, while snow grain size and BC were found to not significantly change throughout the ablation season. Surface albedo was found to have decreased by 0.08 from late July to early August. The albedo simulated by the model agreed with the albedo observed during the study period. However, red snow algae exerted little effect on surface albedo in early August. This is probably owing to the abundance of smaller cells (4.9 x 10(4) cells L-1) when compared with the cell abundance of red snow reported by previous studies in the Arctic region (similar to 10(8) cells L-1). The simulation of snow albedo until the end of the melting season, with a snow algae model, revealed that the reduction in albedo attributed to red snow algae could equal 0.004, out of a total reduction of 0.102 arising from the three impurities on a snowpack in northwest Greenland. Finally, we conducted scenario simulations using the snow albedo model, coupled with the snow algae model, in order to simulate the possible effects of red snow blooming on snow albedo under warm conditions in northwest Greenland. The result suggests that albedo reduction by red snow algal growth under warm conditions (surface snow temperature of +1.5 degrees C) reached 0.04, equivalent to a radiative forcing of 7.5 W m(-2) during the ablation season of 2014. This coupled albedo model has the potential to dynamically simulate snow albedo, including the effect of organic and inorganic impurities, leading to proper estimates of the surface albedo of snow cover in Greenland.