Attributing the impacts of land-cover changes in temperate regions on surface temperature and heat fluxes to specific causes: Results from the first LUCID set of simulations
Attributing the impacts of land-cover changes in temperate regions on surface temperature and heat fluxes to specific causes: Results from the first LUCID set of simulations
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DOI：
10.1029/2011jd017106
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发表时间：
2012-06-30
影响因子：
4.4
通讯作者：
Voldoire, A.
中科院分区：
文献类型：
--
作者：
Boisier, J. P.;de Noblet-Ducoudre, N.;Voldoire, A.
温带地区地表降温是历史上土地利用引起的土地覆盖变化（LULCC）的一种常见的地球物理响应。然而，LUCID所涉及的气候模式显示，温度变化的幅度和季节划分存在显着差异。LULCC引起的冷却是由吸收的太阳辐射的减少，但其幅度是30%至50%，将从单一的辐射变化的预期。这是由于对总湍流能量通量的直接影响（与除蒸散效率或表面粗糙度等地表覆盖特性的变化有关，而不是与其他地表覆盖特性的变化有关），总湍流能量通量在所有季节都会减少，从而在所有模式中引起相对变暖。这些过程的规模因模型而异，导致对LULCC的气候反应不同。为了解决这种不确定性，我们分析了LULCC对地表潜热，潜热和总湍流能量通量的影响，使用多元统计分析来模拟模型的响应。不同的两个主要的“功能”不同，从一个模型到另一个解释的差异：土地覆盖分布和模拟LULCC的敏感性。后者解释了一半以上的模型间传播，并驻留在如何参数化的陆面功能，特别是关于蒸散分配在不同的土地覆盖类型，以及叶面积指数在通量计算的作用。这种不确定性必须通过对我们的陆面模型进行更严格的评估来缩小。
Surface cooling in temperate regions is a common biogeophysical response to historical Land-Use induced Land Cover Change (LULCC). The climate models involved in LUCID show, however, significant differences in the magnitude and the seasonal partitioning of the temperature change. The LULCC-induced cooling is directed by decreases in absorbed solar radiation, but its amplitude is 30 to 50% smaller than the one that would be expected from the sole radiative changes. This results from direct impacts on the total turbulent energy flux (related to changes in land-cover properties other than albedo, such as evapotranspiration efficiency or surface roughness) that decreases at all seasons, and thereby induces a relative warming in all models. The magnitude of those processes varies significantly from model to model, resulting on different climate responses to LULCC. To address this uncertainty, we analyzed the LULCC impacts on surface albedo, latent heat and total turbulent energy flux, using a multivariate statistical analysis to mimic the models' responses. The differences are explained by two major 'features' varying from one model to another: the land-cover distribution and the simulated sensitivity to LULCC. The latter explains more than half of the inter-model spread and resides in how the land-surface functioning is parameterized, in particular regarding the evapotranspiration partitioning within the different land-cover types, as well as the role of leaf area index in the flux calculations. This uncertainty has to be narrowed through a more rigorous evaluation of our land-surface models.