Statistical downscaling estimation of recent rainfall trends in the eastern slope of the Andes mountain range in Argentina
Statistical downscaling estimation of recent rainfall trends in the eastern slope of the Andes mountain range in Argentina
复制标题
阿根廷安第斯山脉东坡近期降雨趋势的统计降尺度估计
DOI：
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发表时间：
2010
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影响因子：
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通讯作者：
J. Labraga
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作者：
J. Labraga
基于多元线性回归技术的降雨降尺度统计模型已经在阿根廷西部的安第斯地区开发和测试，这是一个扩展的山区，三种不同的降雨制度占主导地位，降雨具有很大的时空变异性。验证程序的重点是该模式重现近几十年来观测到的降雨趋势的能力。在阿根廷西北部的热带夏季雨区，降尺度模式对月降水变化的平均贡献率为77%，模式令人满意地再现了上世纪最后20年观测到的负线性趋势。在干旱的阿根廷中西部，一个在两种不同降雨制度之间快速过渡的地区，模型的表现相当差（平均为解释方差的50%），即使如此，模型仍然能够捕捉到该地区北部和南部部门之间线性趋势的显著差异。在阿根廷西南部的中纬度冬季降雨区，用降尺度模式计算的月方差平均为71%，模式能够重现20世纪90年代雨季开始的单一变化。所取得的结果表明，即使在像阿根廷西部这样地形复杂的地区，在月尺度和流域尺度上，在大气变量和降雨量之间建立重要而有用的统计关系也是可行的。
Statistical models for rainfall downscaling based on multiple linear regression techniques have been developed and tested in the Andean Region of west Argentina, an extended mountainous region where three different rain regimes predominate and rainfall has great spatial and temporal variability. The verification procedure was focused on the model’s ability to reproduce observed rainfall trends in recent decades. In the northwest of Argentina, domain of the tropical summer rain regime, the monthly rainfall variance accounted for by downscaling models was 77% on average and models reproduced satisfactorily the negative linear trend observed in the last two decades of the past century. In the arid central-west Argentina, a region of rapid transition between two different rain regimes, model performance was rather poor (an average of 50% of explained variance), even so models were able to capture outstanding differences in the linear trend between the northern and southern sectors of the region. In the southwest of Argentina, domain of the mid-latitude winter rain regime, the monthly variance accounted for by downscaling models was 71% on average and models were capable to reproduce a singular change in the onset of the rainy season that occurred during the 1990s. The results achieved demonstrate that it is feasible to establish significant and useful statistical relationships between atmospheric variables and rainfall at monthly and river basin scales, even for a topographically complex region like western Argentina.