Vanderbilt Institute for Energy and the Environment, Vanderbilt University , PMB 407702, 2301 Vanderbilt Place, Nashville, Tennessee 37240-7702, United States.
Environ Sci Technol. 2015 Mar 3;49(5):2639-47. doi: 10.1021/es504890h. Epub 2015 Feb 9.
Water scarcity is intensified by drought, a phenomenon that impacts many sectors of society and affects virtually all climate zones. The Palmer drought indices are widely used by scientists and policy makers to understand drought and model its components. Despite the spatial heterogeneity and variability in variables required by the Palmer model, regional index values are most commonly used for real-time drought assessment. Local stakeholders charged with developing flexible and tailored water management policies have articulated the need for drought indices calculated at finer spatial resolutions than a regional scale. We use the Pacific Northwest United States (U.S.) as a study area to demonstrate the differences between drought indices calculated for U.S. climate divisions with those calculated at a 0.5° by 0.5° latitude/longitude resolution. Our results indicate that regional values of the two cumulative Palmer drought indices do not represent finer-resolution values well. For half of the study area, the pictures of drought (as determined by regional and finer-resolution values) are drastically different more than 30% of the time. Thus, quite often water managers do not have a clear understanding of the relative severity of drought in their area, which can have serious implications for drought mitigation and adaptation.
水资源短缺因干旱而加剧，这一现象影响着社会的许多部门，几乎影响到所有气候带。帕尔默干旱指数被科学家和政策制定者广泛用于了解干旱并对其组成部分进行建模。尽管帕尔默模型需要空间异质性和变量的可变性，但区域指数值通常用于实时干旱评估。负责制定灵活和定制化水资源管理政策的地方利益相关者已经表达了对计算空间分辨率比区域尺度更精细的干旱指数的需求。我们使用美国太平洋西北地区作为研究区域，以展示为美国气候分区计算的干旱指数与以 0.5°×0.5°经纬度分辨率计算的干旱指数之间的差异。我们的结果表明，这两个累积帕尔默干旱指数的区域值不能很好地代表更精细分辨率的值。在研究区域的一半地区，干旱的情况（由区域和更精细分辨率的值确定）在超过 30%的时间里存在明显差异。因此，水资源管理者往往无法清楚地了解其所在地区干旱的相对严重程度，这可能对干旱缓解和适应产生严重影响。
