ABSTRACT The two primary methods for averaging daily near-surface air temperature are twice-daily averaging (i.e., the sum of the maximum and minimum divided by two) and hourly averaging (i.e., using the 24 hourly values of a day). To quantify the influence of synoptic (air mass) climatology on the numerical difference between the two types of daily temperature averaging, a synoptic climatology for 215 weather stations across the Contiguous United States (CONUS) was developed for the period 1981–2010 and then correlated with those difference values. A significant correlation is found between air mass frequency and the temperature difference, especially during the non-transition seasons (i.e., summer and winter). This pattern is due to the influence of air mass type on the shape of the daily temperature curve. The correlation results also show spatial variability, as air masses that are more frequent in the northern CONUS (e.g., Dry Polar) influence the diurnal temperature curve differently than air masses more common in the southern CONUS (e.g., Moist Tropical). Future work can capitalize on these results by investigating different geographic regions and utilizing this correlation-based approach to analyze how anticipated future changes in the synoptic climatology of air masses influence the diurnal temperature curve.

中文翻译：

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比较每日平均温度方法：天气气候学在确定空间和季节变化中的作用

摘要 平均每日近地表气温的两种主要方法是每日两次平均（即最大值和最小值之和除以二）和每小时平均（即使用一天的 24 小时值）。为了量化天气（气团）气候学对两种类型的日平均温度之间的数值差异的影响，开发了美国本土 (CONUS) 1981-2010 年期间 215 个气象站的天气气候学，然后进行了相关与这些差异值。发现气团频率与温差之间存在显着相关性，尤其是在非过渡季节（即夏季和冬季）。这种模式是由于气团类型对日温度曲线形状的影响。相关结果还显示了空间变异性，因为在美国大陆北部（例如，干极地）更频繁的气团对昼夜温度曲线的影响与在美国大陆南部更常见的气团（例如，潮湿热带）不同。未来的工作可以通过调查不同的地理区域并利用这种基于相关性的方法来分析气团天气气候学的预期未来变化如何影响昼夜温度曲线，从而利用这些结果。