Separating the effects of changes in land cover and climate: a hydro-meteorological analysis of the past 60 yr in Saxony, Germany
Separating the effects of changes in land cover and climate: a hydro-meteorological analysis of the past 60 yr in Saxony, Germany
复制标题
DOI：
10.5194/hess-18-389-2014
复制
发表时间：
2013-07
影响因子：
6.3
通讯作者：
M. Renner;K. Brust;K. Schwärzel;M. Volk;C. Bernhofer
中科院分区：
文献类型：
--
作者：
M. Renner;K. Brust;K. Schwärzel;M. Volk;C. Bernhofer
了解并量化气候和土地利用/土地覆盖变化对可用水量的影响是调整水管理的先决条件；然而，很难区分这些不同影响的影响。在本文中，我们阐述了一种基于 Budyko 框架的分离和归因方法。我们假设蒸散量 ( E T ) 受到降水 ( P ) 和蒸发需求 ( E 0 ) 的气候强迫的限制，但会受到地表特性的影响。气候变化（即 E 0 / P ）或地表变化对 E T 的影响改变了描述相对水（ E T / P ）和能量分配（ E T / E 0 ）的两个无量纲度量，这使我们能够分离和量化这些影响。我们使用 1950-2009 年期间覆盖德国联邦萨克森州大部分地区的 68 个中小型河流流域，使用分离方法来量化环境因素对 E T 的作用。该地区可以被视为典型的中欧景观，具有相当大的人为影响。从长远来看，大多数盆地都遵循布迪科曲线，我们将其解释为气候、土壤和植被强烈相互作用的结果。但两组盆地有偏差。低海拔地区以农业为主的盆地超过了布迪科曲线，而一组高海拔、森林覆盖的盆地则远低于布迪科曲线。当可视化水和能源相对分配的十年动态时，气候和地表变化的影响变得显而易见。 1960 年后，森林覆盖较高的盆地经历了巨大的地表变化，这表明空气污染造成的树木损害导致年 E T 下降了 38% 左右。相比之下，地势较低、以农业为主的地区在此期间没有出现显着变化。然而，自20世纪90年代以来，有效的工业污染缓解措施已经建立，明显的增亮和再生导致大多数流域的ET显着增加。总之，关于水和能量平衡的数据对于了解长期气候和土地覆盖如何控制蒸散以及水的可用性是必要的。此外，检测到的地表变化影响在空间和时间上与独立的森林损害数据一致，从而证实了分离方法的有效性。
Understanding and quantifying the impact of changes in climate and land use/land cover on water availability is a prerequisite to adapt water management; yet, it can be difficult to separate the effects of these different impacts. In this paper we illustrate a separation and attribution method based on a Budyko framework. We assume that evapotranspiration ( E T ) is limited by the climatic forcing of precipitation ( P ) and evaporative demand ( E 0 ), but modified by land-surface properties. Impacts of changes in climate (i.e., E 0 / P ) or land-surface changes on E T alter the two dimensionless measures describing relative water ( E T / P ) and energy partitioning ( E T / E 0 ), which allows us to separate and quantify these impacts. We use the separation method to quantify the role of environmental factors on E T using 68 small to medium range river basins covering the greatest part of the German Federal State of Saxony within the period of 1950–2009. The region can be considered as a typical central European landscape with considerable anthropogenic impacts. In the long term, most basins are found to follow the Budyko curve which we interpret as a result of the strong interactions of climate, soils and vegetation. However, two groups of basins deviate. Agriculturally dominated basins at lower altitudes exceed the Budyko curve while a set of high altitude, forested basins fall well below. When visualizing the decadal dynamics on the relative partitioning of water and energy the impacts of climatic and land-surface changes become apparent. After 1960 higher forested basins experienced large land-surface changes which show that the air pollution driven tree damages have led to a decline of annual E T on the order of 38%. In contrast, lower, agricultural dominated areas show no significant changes during that time. However, since the 1990s effective mitigation measures on industrial pollution have been established and the apparent brightening and regrowth has resulted in a significant increase of E T across most basins. In conclusion, data on both, the water and the energy balance is necessary to understand how long-term climate and land cover control evapotranspiration and thus water availability. Further, the detected land-surface change impacts are consistent in space and time with independent forest damage data and thus confirm the validity of the separation approach.