Accurate, high‐resolution measurements of the precipitation diurnal cycle are important for understanding local variations in precipitation and the underlying processes which cause them. Combining 16 years of measurements from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) and 4 years from the Global Precipitation Measurement (GPM) Dual‐frequency Precipitation Radar (DPR) creates a 20‐year mean of near surface precipitation rate at 0.1° × 0.1°, hourly resolution from 35°N to 35°S. Similar data sets are created using the same proportions of the TRMM Microwave Imager and GPM Microwave Imager measurements, and 18 years of the Integrated Multi‐satellitE Retrievals for GPM (IMERG) precipitation product. The phase and amplitude of the diurnal variation from each data set are calculated at each grid point using a fast Fourier transform (FFT). The satellite data are validated with 14 years of hourly National Climatic Data Center rain gauge measurements over the southeast United States by applying the same FFT method. Spaceborne radar best represents the unaveraged magnitude and diurnal phase measured by the gauges in this region. Time delays are found in precipitation retrievals from passive microwave observations as well as in the IMERG product. The strengths and weaknesses of these high‐resolution data sets in determining the diurnal cycle of precipitation on a climatological scale are discussed across the tropics and subtropics. In general, when compared to PR and DPR retrievals, IMERG overestimates the global precipitation and has varying time lags, which tend to be larger and earlier over regions where organized convective systems are common.

中文翻译：

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星载雷达，无源微波辐射计和IMERG估算的降水日变化的差异

准确，高分辨率的降水昼夜周期测量对于了解降水的局部变化和引起降水的潜在过程非常重要。来自热带雨量测量团（TRMM）降水雷达（PR）的16年测量和来自全球降水测量（GPM）的4年双频降水雷达（DPR）的测量相结合，得出了近地表降水率的20年平均值。 0.1°×0.1°，小时分辨率从35°N到35°S。使用相同比例的TRMM微波成像仪和GPM微波成像仪测量结果以及18年的GPM（IMERG）降水综合多卫星检索结果创建了相似的数据集。使用快速傅里叶变换（FFT）在每个网格点计算每个数据集的昼夜变化的相位和幅度。通过应用相同的FFT方法，通过美国东南部每小时14年的国家气候数据中心雨量计测量值对卫星数据进行了验证。星载雷达最能代表该地区测距仪测得的非平均幅度和昼夜相位。在被动微波观测以及IMERG产品的降水量检索中发现了时间延迟。在整个热带和亚热带地区，都讨论了这些高分辨率数据集在确定气候尺度上降水日变化周期方面的优缺点。通常，与PR和DPR检索相比，