Impacts of anthropogenic forcing and internal variability at the watershed scale - going from the daily to the hourly time scale

流域尺度上的人为强迫和内部变异的影响 - 从每日到每小时的时间尺度

• 批准号: RGPIN-2020-07242
• 负责人: Brissette, Francois
• 金额: $ 3.13万
• 依托单位: École de technologie supérieure
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=753898
• 关键词: Impacts; anthropogenic; forcing; internal; variability

Climate change resulting from the anthropogenic impact on radiative forcing is now well established. In addition to increases in projected surface temperatures, the changes will affect all major components of the water cycle, including variability and intensity of rainfall at various spatial and temporal scales. The knowledge of the impacts of these changes comes largely from general circulation and earth system models. However, due to the limitations related to the available computing power, the outputs of these models have mostly been available at the daily time-step until recently. Changes at the sub-daily scales are therefore less well documented. Nevertheless, releases of higher-resolution regional climate models (convection-permitting or not) indicate that the impacts of anthropogenic forcing will be greater for short-duration and intense rainfall. We can thus predict a disproportionate impact on small watersheds whose hydrological response is rapid and commensurable with that of convective precipitation systems. Similarly, we can also predict a decrease in the impact of snowmelt related floods to those related to summer fall precipitation over small watersheds (<1000 km2). In hydrology, these results point to major impacts towards small rural and urbanized watersheds. The potential impacts of anthropogenic forcing change on the hydrology of these basins have been poorly studied for two main reasons: 1-There is no reliable hydrometeorological database at sub-daily time steps in North America (as well as in the majority of the world, except for a few European countries) to study these watersheds in sufficient numbers; 2-There are still few climate models whose main outputs (e.g. temperature and precipitation) are available at the sub-daily time steps. This research program specifically aims to fill this knowledge gap by using the tools and methodologies developed within our research laboratory and elsewhere to study the impacts of climate change at the daily time step on small to medium-size watersheds. These tools and methods will be combined with the use of new databases and outputs of climate models with high temporal and spatial resolution to thus be able to tackle the study of small to mdieum-size watersheds up to the hourly time step and below.

人类对辐射强迫的影响所造成的气候变化现已得到充分确认。除了预估的地表温度升高外，这些变化还将影响水循环的所有主要组成部分，包括在不同时空尺度上的降雨变率和强度。对这些变化影响的认识主要来自大气环流和地球系统模式。然而，由于可用计算能力的限制，直到最近，这些模型的输出大多是在日常时间步长可用的。因此，亚日尺度的变化记录较少。然而，发布的高分辨率区域气候模式（允许或不允许对流）表明，对于短时强降雨，人为强迫的影响将更大。因此，我们可以预测对小流域的不成比例的影响，这些小流域的水文响应迅速，与对流降水系统的水文响应可比较。同样，我们还可以预测，在小流域（<1000 km2）上，融雪相关洪水的影响将减少与夏秋降水相关的洪水的影响。在水文学方面，这些结果指出了对小型农村和城市化流域的重大影响。人为强迫变化对这些流域水文的潜在影响的研究很少，主要有两个原因：1 .在北美（以及世界上大多数国家，除了少数欧洲国家），没有可靠的亚日时间步长的水文气象数据库来研究这些流域的足够数量；在亚日时间步长的气候模式中，主要输出（如温度和降水）仍然很少。本研究项目旨在通过使用我们研究实验室和其他地方开发的工具和方法来研究气候变化在日常时间步对中小型流域的影响，从而填补这一知识空白。这些工具和方法将与使用新的数据库和具有高时间和空间分辨率的气候模式的输出相结合，从而能够处理每小时及以下时间步长的中小型流域的研究。