标题： 使用LOFAR通过事件特定的GDAS大气重建空气簇射参数 显示英文标题

标题： Reconstructing air shower parameters with LOFAR using event specific GDAS atmospheres

摘要： 对湿度、压力、温度和折射率等大气参数的有限了解是重建宇宙射线空气簇射中最大簇射深度时的重要系统不确定性之一。 当前的空气簇射蒙特卡洛模拟代码如CORSIKA和无线电插件CoREAS使用各种平均化的参数化大气模型。 然而，为了用于LOFAR数据的宇宙射线分析方法，需要时间依赖性和地点特定的大气模型。 在那里，对于每个检测到的宇宙射线都会使用专门的模拟集，以考虑测量时的实际大气条件。 利用全球数据同化系统（GDAS），一个全球大气模型，我们已在CORSIKA和CoREAS中实现了时间依赖的现实大气剖面。 我们为所有用LOFAR测量的空气簇射生成了现实的事件特定大气，这些事件覆盖了好几年和多种不同的天气条件。 对我们的数据集进行全面重新分析显示，对于大多数数据，我们之前的校正因子表现相当不错；我们发现重建的$X_{\rm max}$中只有很小的系统性偏移，为2 g/cm$^2$。 然而，在极端天气条件下，例如非常低的空气压力，偏移可以达到15 g/cm$^2$。 我们提供了一个校正公式，用于确定由于使用美国标准大气和基于GDAS的大气进行模拟比较而产生的$X_{\rm max}$中的偏移。 显示英文摘要

摘要： The limited knowledge of atmospheric parameters like humidity, pressure, temperature, and the index of refraction has been one of the important systematic uncertainties in reconstructing the depth of the shower maximum from the radio emission of air showers. Current air shower Monte Carlo simulation codes like CORSIKA and the radio plug-in CoREAS use various averaged parameterized atmospheres. However, time-dependent and location-specific atmospheric models are needed for the cosmic ray analysis method used for LOFAR data. There, dedicated simulation sets are used for each detected cosmic ray, to take into account the actual atmospheric conditions at the time of the measurement. Using the Global Data Assimilation System (GDAS), a global atmospheric model, we have implemented time-dependent, realistic atmospheric profiles in CORSIKA and CoREAS. We have produced realistic event-specific atmospheres for all air showers measured with LOFAR, an event set spanning several years and many different weather conditions. A complete re-analysis of our data set shows that for the majority of data, our previous correction factor performed rather well; we found only a small systematic shift of 2 g/cm$^2$ in the reconstructed $X_{\rm max}$. However, under extreme weather conditions, for example, very low air pressure, the shift can be up to 15 g/cm$^2$. We provide a correction formula to determine the shift in $X_{\rm max}$ resulting from a comparison of simulations done using the US-Std atmosphere and the GDAS-based atmosphere.