Land surface impacts on subseasonal and seasonal predictability
Land surface impacts on subseasonal and seasonal predictability
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DOI：
10.1029/2011gl049945
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发表时间：
2011-12
影响因子：
5.2
通讯作者：
Zhichang Guo;P. Dirmeyer;T. DelSole
中科院分区：
文献类型：
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作者：
Zhichang Guo;P. Dirmeyer;T. DelSole
本文表明，实际初始化的陆地表面状态显著提高了夏季2 - 3个月的大气可预测性。土地初始化对大气可预测性影响的空间结构可以通过土壤水分记忆时间和地表-蒸散发耦合强度的同步影响来解释。提出了一种基于土壤水分和蒸发异常的替代方法。结果还表明，地表对大气可预测性的影响随季节而变化，在寒带春季和秋季可预测性增强相对较小，在寒带夏季可预测性增强最大。值得注意的是，从春季到夏季，气温和降水的可预测性随着提前时间的增加而增加。这种增加被诊断为可预测性从陆地向大气的“转移”：在春季，土壤湿度的可预测性很高，但由于缺乏陆地-大气耦合，这种可预测性不会影响大气；在夏季，耦合增加，从而将可预测性从陆地转移到大气。
This paper shows that realistically initialized land surface states enhance atmospheric predictability significantly out to two‐to‐three months during summer. The spatial structure of the impact of land initialization on atmospheric predictability can be explained by the simultaneous influence of soil moisture memory time and land surface‐evapotranspiration coupling strength. A proxy for this impact based on soil moisture and evaporation anomalies is proposed. The results also show that the impact of the land surface on atmospheric predictability varies with season: enhancement of predictability is relatively small during boreal spring and autumn, and reaches a maximum during boreal summer. Remarkably, the predictability of atmospheric temperature and precipitation increases with lead time from spring to summer. This increase is diagnosed as a “transfer” of predictability from land to atmosphere: during spring, the soil moisture predictability is high, but this predictability does not impact the atmosphere due to lack of land‐atmosphere coupling; during summer, the coupling increases, thereby transferring the predictability from land to atmosphere.