Climate change impact on the water regime of two great Arctic rivers: modeling and uncertainty issues
Climate change impact on the water regime of two great Arctic rivers: modeling and uncertainty issues
复制标题
气候变化对北极两条大河水情的影响：建模和不确定性问题
作者：
A. Gelfan;D. Gustafsson;Yury Motovilov;B. Arheimer;A. Kalugin;I. Krylenko;A. Lavrenov
建立了应用地球物理生态模型(ECOMAG)和基于环境水文预测(HYPE)过程的水文模型，以评估气候变化对勒拿河和麦肯齐河两个泛北极大流域水文情势的可能影响。我们首先评估了水文模型再现历史径流序列的可靠性，并分析了气候变化情景驱动的水文预测。使用五个全球气候模型(GCM)和四个典型集中路径(RCP)情景对三个30年期间(早期-(2006-2035年)、中期(2036-2065年)和本世纪末(2070-2099年))的影响进行了评估。结果特别表明，盆地对RCP2.6的变化，即所谓的“缓解”情景的反应有多年的延迟，因此对潜在的缓解措施也有反应。然后，我们对由GCM和RCP的不确定性引起的水文预测的变异性进行了评估，发现变异性随着预测的时间范围而增加，总体上，Mackenzie的预测变率比Lena的大。最后，我们比较了基于GCM数据的21世纪平均年径流异常与基于改进的观测气候方法在Lena盆地使用的三角洲变化方法所预测的相应异常。我们发现，比较的预测与本世纪初密切相关。因此，对于Lena流域，修正的观测气候学可用作基于水文模型的预测的驱动力，并被视为基于GCM的情景的替代方案。
The ECOlogical Model for Applied Geophysics (ECOMAG) and the HYdrological Predictions for the Environment (HYPE) process-based hydrological models were set up to assess possible impacts of climate change on the hydrological regime of two pan-Arctic great drainage basins of the Lena and the Mackenzie Rivers. We firstly assessed the reliability of the hydrological models to reproduce the historical streamflow series and analyzed the hydrological projections driven by the climate change scenarios. The impacts were assessed for three 30-year periods (early- (2006–2035), mid- (2036–2065), and end-century (2070–2099)) using an ensemble of five global climate models (GCMs) and four Representative Concentration Pathway (RCP) scenarios. Results show, particularly, that the basins react with a multi-year delay to changes in RCP2.6, so-called “mitigation” scenario, and consequently to the potential mitigation measures. Then, we assessed the hydrological projections’ variability, which is caused by the GCM’s and RCP’s uncertainties, and found that the variability rises with the time horizon of the projection, and generally, the projection variability is larger for the Mackenzie than for the Lena. We finally compared the mean annual runoff anomalies projected under the GCM-based data for the twenty-first century with the corresponding anomalies projected under a modified observed climatology using the delta-change method in the Lena basin. We found that the compared projections are closely correlated for the early-century period. Thus, for the Lena basin, the modified observed climatology can be used as driving force for hydrological model-based projections and considered as an alternative to the GCM-based scenarios.