模拟气候变化和CO_2增加对高寒草原土壤有机碳的影响(英文)

Modeling the Effects of Climate Change and Elevated CO_2 on Soil Organic Carbon in an Alpine Steppe

本研究的目标是利用CENTURY模型分析气候变化、大气CO2浓度倍增、气候变化与大气CO2浓度倍增共同作用对藏北高原高寒草原土壤有机碳的影响。结果表明:未来50年不同气候变化情景下土壤表层(0-20cm)有机碳呈降低趋势,变化率为49.77%-52.36%。P1T0情景(降水增加,温度不变)、P0T1情景(降水不变,温度增加)和P1T1情景(降水增加,温度增加)下的模拟结果相近。其中P1T1情景下高寒草原土壤有机碳损失的最多(模拟结束时的土壤有机碳为844.40 g C m-2),P0T1情景下土壤有机碳损失49.77%。相对CO2不变情景而言,CO2倍增情景下土壤有机碳增加12.87%。CO2增加对土壤有机碳的影响大于气候变化单独作用对土壤有机碳的影响。气候变化与大气CO2浓度倍增共同作用导致土壤有机碳降低。未来50年P1T1+2×CO2情景下土壤有机碳降低52.39%,P0T1+2×CO2情景下土壤有机碳降低49.81%,P1T0+2×CO2情景下土壤有机碳降低52.30%。因此,高寒草原土壤有机碳含量随降水、温度和大气CO2浓度的变化而变化。

The objective of this study was to analyze the effects of climate change and doubled atmospheric CO2 concentrations, as well as the combined effects of climate change and doubling atmospheric CO2 concentrations on soil organic carbon （SOC） in the alpine steppe of the northern Tibetan Plateau using the CENTURY model. The results indicate that SOC loss in climate change scenarios varied from 49.77 52.36% in the top 20 cm. The simulation results obtained for a P1T0 scenario （increased precipitation and unchanged temperature）, POT1 scenario （unchanged precipitation and increased temperature）, and P1T1 scenario （increased precipitation and increased temperature） were similar. The alpine steppe in the P1T1 scenarios lost the greatest amount of SOC （844.40 g C m-2, representing the least amount of SOC） by the end of the simulation. The simulation for POT1 scenarios resulted in a 49.77% loss of SOC. However, SOC increased 12.87% under the COs doubling scenario, compared with the unchanged CO2 scenario. CO2 enhancement effects on SOC were greater than the climate change effects on SOC alone. The simulation of combined climate change and doubling atmospheric CO2 led to a decrease in SOC. This result indicated a decrease of 52.39% in SOC for the P1T1 ＋ 2 × CO2 scenario, 49.81% for the POT1 ＋ 2 ×CO2 scenario, and 52.30% for the P1T0 ＋ 2 ×CO2 scenario over the next 50 years. Therefore, SOC content in the alpine steppe will change because of changes in precipitation, temperature and atmospheric CO2 concentrations.