The aim of this study is to analyze the spatial and temporal structure of drought over the continental United States (CONUS) and their teleconnection at different timescales from observations and climate models. We use the standardized precipitation evapotranspiration index (SPEI) at 12- and 24-month timescales as the drought index. Spatial patterns of drought regimes are delineated by using the principal component analysis (PCA) while the temporal characteristics of the variability of each drought pattern and teleconnection with climate indices are analyzed by using the wavelet analysis. Wavelet coherence of the drought pattern and four climate indices: El Niño-Southern Oscillation (ENSO), Pacific decadal oscillation (PDO), Atlantic multidecadal oscillation (AMO), and North Atlantic Oscillation (NAO) are analyzed. The results show that major drought patterns are located over the Northwest, South, Upper Midwest, and East regions. The spatial pattern of the drought regimes is similar for the 12- and 24-month timescale drought. ENSO influences the drought over West and South at decadal timescales throughout the study period (1950–2015) while intermittent significant coherence is observed at interannual timescale. The coherence of NAO and PDO with SPEI-12 is decreased during recent decades. Generally, regional climate model (RCM)-simulated drought patterns are more localized in a smaller area over the region compared to the spatial extent of observed drought patterns. Power spectra of seasonal to interannual variability (2–5-yr period) of all four drought patterns from RCM simulations are similar to those from the observations. However, at larger periodicities (decadal variations) among-RCM spread increases with increasing periods.

这项研究的目的是从观测和气候模型分析美国大陆（CONUS）上干旱的时空结构及其在不同时间尺度上的遥相关性。我们使用12个月和24个月时间尺度上的标准化降水蒸散指数（SPEI）作为干旱指数。利用主成分分析（PCA）描绘了干旱状况的空间格局，同时利用小波分析分析了每种干旱格局的变异性和与气候指数的遥相关的时间特征。分析了干旱模式和四个气候指数的小波相干性：厄尔尼诺-南方涛动（ENSO），太平洋年代际振荡（PDO），大西洋多年代际振荡（AMO）和北大西洋涛动（NAO）。结果表明，主要的干旱模式位于西北，南部，中西部上，东部地区。对于12个月和24个月的时间尺度干旱，干旱制度的空间格局相似。在整个研究期间（1950-2015年），ENSO在年代际尺度上影响西部和南部的干旱，而在年际尺度上观测到间歇性的显着连贯性。近几十年来，NAO和PDO与SPEI-12的一致性降低了。通常，与观测到的干旱模式的空间范围相比，区域气候模式（RCM）模拟的干旱模式更多地位于该区域的较小区域中。RCM模拟得出的所有四种干旱模式的季节到年际变化的功率谱（2-5年期）与观测值相似。然而，