Sensitivity of atmospheric response to modeled snow anomaly characteristics
Sensitivity of atmospheric response to modeled snow anomaly characteristics
复制标题
DOI：
10.1029/2003jd004160
复制
发表时间：
2004-03
影响因子：
--
通讯作者：
G. Gong;D. Entekhabi;J. Cohen;D. Robinson
中科院分区：
文献类型：
--
作者：
G. Gong;D. Entekhabi;J. Cohen;D. Robinson
[1]大片陆地表面积雪不仅会降低当地的地表温度，还会影响各种偏远的气候现象。然而，产生这种响应的具体机制和积雪异常特征仍不是很清楚。本文利用大集合大气环流模式(GCM)试验研究了大气对积雪和积雪深度异常响应的敏感性，以及与之相关的地表热力过程。西伯利亚上空实际的、以观测为基础的秋冬强迫雪被开发并用作模式边界条件，以评估(1)包括积雪和雪深分量的综合强迫雪的气候响应，(2)仅包括积雪覆盖的强迫雪，和(3)没有地面反照率响应的强迫雪。结果表明，积雪范围异常并不是唯一对局地温度响应有显著贡献的因素，雪深异常也具有类似的影响。此外，反照率效应不是主要的热力学机制；还涉及与积雪的绝缘性质有关的过程(例如，热导率和潜热通量)。最后，我们发现，实际的积雪覆盖和积雪深度异常需要共同作用才能产生足够强的局地温度响应，以明显调制冬季北极涛动(AO)模式，如先前的研究所表明的那样。这样详细地了解大气对雪异常特征的敏感性，有助于有效地利用雪异常信号中包含的任何潜在的气候可预报性。索引词：1863水文学：冰雪(1827)；1833水文学：水文气候学；3322气象与大气动力学：陆地/大气相互作用；关键词：雪、气候
[1] The presence of snow over broad land surface regions has been shown to not only suppress local surface temperatures, but also influence various remote climate phenomena. However, the specific mechanisms and snow anomaly characteristics which produce this response are still not well understood. In this study, large-ensemble general circulation model (GCM) experiments are performed to investigate the sensitivity of the atmospheric response to snow cover vs. snow depth anomalies, and the relevant surface thermodynamic processes involved. Realistic, observation-based, autumn-winter snow forcings over Siberia are developed and applied as model boundary conditions, to evaluate the climate response to (1) comprehensive snow forcings including snow cover and snow depth components, (2) snow cover only forcings, and (3) snow forcings in the absence of a surface albedo response. Results indicate that snow cover extent anomalies are not the only significant contributor to the local temperature response; snow depth anomalies are shown to have a comparable effect. Furthermore, the albedo effect is not the predominant thermodynamic mechanism; processes related to the insulative properties of the snowpack (e.g., thermal conductivity and latent heat flux) are also involved. Lastly, we find that realistic snow cover and snow depth anomalies acting in conjunction are required to produce a local temperature response which is strong enough to distinctly modulate the winter Arctic Oscillation (AO) mode as shown in previous studies. Such a detailed understanding of the atmospheric sensitivity to snow anomaly characteristics is beneficial for effectively utilizing any potential climate predictability contained in snow anomaly signals. INDEX TERMS: 1863 Hydrology: Snow and ice (1827); 1833 Hydrology: Hydroclimatology; 3322 Meteorology and Atmospheric Dynamics: Land/atmosphere interactions; KEYWORDS: snow, climate