Fire effects on surface‐atmosphere energy exchange in Alaskan black spruce ecosystems: Implications for feedbacks to regional climate
Fire effects on surface‐atmosphere energy exchange in Alaskan black spruce ecosystems: Implications for feedbacks to regional climate
复制标题
火灾对阿拉斯加黑云杉生态系统地表大气能量交换的影响：对区域气候反馈的影响
DOI：
10.1029/2001jd000530
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发表时间：
2002
影响因子：
--
通讯作者：
F. Chapin
中科院分区：
文献类型：
--
作者：
S. Chambers;F. Chapin
[1]虽然火对地球上第二大生物群落的北方森林的功能和多样性至关重要，但很少有关于这些地区干扰对地表-大气相互作用的影响的详细研究。我们进行了基于塔的微气象测量，在夏季超过6个最近烧毁的黑云杉的立场，不同的年龄在0和14年之间。结果显示为非沉淀条件。有一个最初的减少最小的火灾后从0.09到0.06，然后迅速增加到0.135的演替植被覆盖的增加。对于当地太阳正午附近的晴朗天空条件，由于地表-大气耦合减少而导致的地表温度升高和太阳活动的综合影响，在连续的第一个十年中使正午净辐射减少了9.3%（170 W m−2）。平均每日净辐射下降了5.5%。接近中午，净辐射到地面热通量的相对分区增加了一倍，附近的未燃烧的立场相比，虽然每天的基础上，增加只有在火灾后的头几年显着。减少净辐射，增强地面热通量，减少波文比值以下的第一个十年的继承可能会导致中午减少约80 W m−2的显热通量相比，未燃烧的立场。跨越火痕边界，显热和粗糙度的对比是足够大，以诱导中尺度环流，并可能触发对流发展。由于火痕经常超过104公顷，局部较冷的条件将占上风，抑制行星边界层的发展。由于阿拉斯加内陆有大量的火灾干扰，这些影响可能会导致区域气候模式。
[1] Although fire is crucial to the functioning and diversity of boreal forests, the second largest biome on Earth, there are few detailed studies of the effects of disturbance on surface-atmosphere interactions in these regions. We conducted tower-based micrometeorological measurements in summer over six recently burned black spruce stands that varied in age between 0 and 14 years. Results are presented for nonprecipitating conditions. There was an initial reduction of minimum albedo following fire from ∼0.09 to 0.06 followed by a rapid increase to 0.135 as the cover of successional vegetation increased. For clear-sky conditions near local solar noon, the combined effects of increased surface temperature due to a reduced surface-atmospheric coupling and albedo reduced midday net radiation by 9.3% (∼70 W m−2) for the first decade of succession. The average daily net radiation declined by 5.5%. Near noon, the relative partitioning of net radiation into ground heat flux doubled compared to nearby unburned stands, although on a daily basis the increase was only significant for the first few years following fire. Reduced net radiation, enhanced ground heat flux, and reduced Bowen ratio values following the first decade of succession could lead to a midday reduction of approximately 80 W m−2 in sensible heat flux compared to an unburned stand. Across a fire-scar boundary, the contrast in sensible heating and roughness is sufficiently large to induce mesoscale circulations and possibly trigger convective development. Because fire scars frequently exceed 104 ha, locally cooler conditions would prevail with suppressed planetary boundary layer development. Given the abundance of fire disturbance throughout interior Alaska, these effects may contribute to the regional climate patterns.