分类： 地球科学 >> 地球科学史 提交时间： 2020-06-22 合作期刊: 《干旱区科学》
摘要： Drought is one of the most significant environmental disasters, especially in arid and semi-arid regions. Drought indices as a tool for management practices seeking to deal with the drought phenomenon are widely used around the world. One of these indicators is the Palmer drought severity index (PDSI), which is used in many parts of the world to assess the drought situation and continuation. In this study, the drought state of Fars Province in Iran was evaluated by using the PDSI over 1995–2014 according to meteorological data from six weather stations in the province. A statistical downscaling model (SDSM) was used to apply the output results of the general circulation model in Fars Province. To implement data processing and prediction of climate data, a statistical period 1995–2014 was considered as the monitoring period, and a statistical period 2019–2048 was for the prediction period. The results revealed that there is a good agreement between the simulated precipitation (R2>0.63; R2, determination coefficient; MAE0.95, MAE<1.74, and RMSE<1.78) with the observed data from the stations. The results of the drought monitoring model presented that dry periods would increase over the next three decades as compared to the historical data. The studies showed the highest drought in the meteorological stations Abadeh and Lar during the prediction period under two future scenarios representative concentration pathways (RCP4.5 and RCP8.5). According to the results of the validation periods and efficiency criteria, we suggest that the SDSM is a proper tool for predicting drought in arid and semi-arid regions.
分类： 地球科学 >> 大气科学 提交时间： 2021-09-14 合作期刊: 《干旱区研究》
摘要： 选取腾格里沙漠南缘对气候变化敏感的昌岭山为研究区，通过分析昌岭山优势树种青海云杉树轮宽度年表与气候因子的相关关系，得出5—7月PDSI（帕默尔干旱指数）与树轮宽度年表的相关性较强（r=0.621，P<0.001），干旱是影响树木径向生长的主控气候因子；通过建立树轮宽度年表和PDSI的线性回归方程，重建了研究区过去146 a以来的PDSI干旱变化；同时基于重建的PDSI的年际变化表明：研究区在过去146 a间共经历了4个干旱期（1882—1894年，1915—1936年，1966—1978年，1989—2015年）。周期分析结果显示重建序列存在2 a、2.6~3 a、11 a左右的变化周期，说明研究区气候变化主要受厄尔尼诺-南方涛动（ENSO）和太阳黑子活动的驱动。研究结论对于探讨中国西北干湿变化规律及预测未来气候变化条件下该区域亚高山森林生态系统的变化提供了科学依据。
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