磁偏角（D）的水平梯度不仅随纬度变化，而且随经度变化。
The horizontal gradient of the declination (D) varies not only with latitude, but also with longitude.
机场运行需要跑道上的磁偏角，但本次实际观测数据表明，机场路道上的磁偏角因受机场环境影响，不同地方变化很大，不能反映机场整个区域的实际情况。
According to the specified observation data, it found that the magnetic declinations on airdrome runway varied greatly; therefore, it couldn't reflect the real condition for the airdrome whole area.
机场运行需要跑道上的磁偏角，但本次实际观测数据表明，机场路道上的磁偏角因受机场环境影响，不同地方变化很大，不能反映机场整个区域的实际情况。
According to the specified observation data, it found that the magnetic declinations on airdrome runway varied greatly; therefore, it couldn't reflect the real condition for the airdrome whole area.
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