选取了2008年的地磁总场与分量组合观测系统FHDZ-M15的观测资料，利用一阶差分计算参考背景噪声的方法，对子夜时段参考背景噪声和特静时段参考背景噪声两个时段进行分析比较。结果显示，选用特静时段方法计算出的参考背景噪声普遍比用子夜时段计算出的参考背景噪声要小，但都能反映出参考背景噪声随季节和纬度的变化而变化。

Selected the observed files of geomagnetic field and component combination observation system FHDZ-M15,by the method of calculating reference background noise with first order difference, based on data of 4 stations in the year of 2008 respectively, we analyze midnight period and particular static period. The result reveals that the noise caculating by the data of particular static period is generally smaller than that of midnight period, however, both noise can show us that the reference background noise changes with the season and latitude