Natural lightning and the associated clouds are known to behave differently over land and ocean, but many questions remain. We expand the related observational datasets by obtaining simultaneous quasi-static electric field observations over coastal land, near-shore water, and deep ocean regions during both fair-weather and thunderstorm periods. Oceanic observations were obtained using two 3-m NOAA buoys that were instrumented with Campbell Scientific electric field mills to measure the quasi-static electric fields. These data were compared to selected electric field records from the existing on-shore electric field mill suite of 31 sensors at Kennedy Space Center (KSC). Lightning occurrence times, locations and peak current estimates for both onshore and ocean were provided by the U.S. National Lightning Detection Network. The buoy instruments were first evaluated on-shore at the Florida coast, and the first system was calibrated for field enhancements and to confirm proper behavior of the system in elevated-field environments. The buoys were then moored 20 mi and 120 mi off the coast of KSC in February (20 mi) and August (120 mi) 2014. Diurnal fair-weather fields at both ocean sites matched will with each other and with those found during the Carnegie cruise, but mean values were 33% smaller, due at least in-part to constraints on the calibration procedure. Diurnal fair-weather fields variations at coastal and inland sites were a poorer match than offshore, likely because the offshore environment is “cleaner” with limited variations in local space charge, lower surface aerosol densities, little surface heating to disturb the surface charge layer during fair weather, and fewer local radioactive sources to modulate the near-surface electrical conductivity. Storm-related static fields were 4-5× larger at both oceanic sites than over land, likely due to decreased screening by near-surface space charge produced by corona current. The time-evolution of the electric field and field changes during storm approach are sufficiently different over land and ocean to warrant further study. This work shows the quality, accuracy, and reliability of these data, and has demonstrated the practicality of off-shore electric field measurements for safety- and launch-related decision making at KSC.

众所周知，自然闪电和相关的云层在陆地和海洋上的行为不同，但是仍然存在许多问题。我们通过获取在晴天和雷暴期间对沿海土地，近岸水域和深海区域的同时准静态电场观测值来扩展相关的观测数据集。使用两个3 m的NOAA浮标获得了海洋观测结果，这些浮标由Campbell Scientific电场研磨仪进行了测量，以测量准静态电场。将这些数据与肯尼迪航天中心（KSC）现有的陆上电场磨机套件（包括31个传感器）中选定的电场记录进行了比较。美国国家闪电检测网络提供了陆上和海洋的闪电发生时间，位置和峰值电流估计。首先在佛罗里达海岸的岸上对浮标仪器进行了评估，并且对第一个系统进行了校准以增强场强，并确认该系统在高场环境中的正常运行。然后，分别在2014年2月（20英里）和8月（120英里）的KSC海岸将浮标停泊在20英里和120英里处。两个海洋站点的日间晴天场相互匹配，并且与卡内基期间发现的场相匹配巡航，但平均值至少减少了33％，这至少部分是由于校准程序的限制。与沿海地区相比，沿海和内陆地区昼间的晴天天气场变化较差，这可能是因为海上环境“更清洁”，局部空间电荷变化有限，地表气溶胶密度较低，在晴朗的天气中，几乎没有表面加热会干扰表面电荷层，而较少的本地放射源会调节近地表电导率。在两个海洋站点，与风暴有关的静态场都比陆地上大4-5倍，这可能是由于电晕电流产生的近地表空间电荷的屏蔽作用减弱了。风暴进场期间电场和场变化的时间演化在陆地和海洋上有足够的差异，值得进一步研究。这项工作显示了这些数据的质量，准确性和可靠性，并证明了海上电场测量对于KSC安全和发射相关决策的实用性。在两个海洋站点，与风暴有关的静态场都比陆地上大4-5倍，这可能是由于电晕电流产生的近地表空间电荷的屏蔽作用减弱了。风暴进场期间电场和场变化的时间演化在陆地和海洋上有足够的差异，值得进一步研究。这项工作显示了这些数据的质量，准确性和可靠性，并证明了海上电场测量对于KSC安全和发射相关决策的实用性。在两个海洋站点，与风暴有关的静态场都比陆地上大4-5倍，这可能是由于电晕电流产生的近地表空间电荷的屏蔽作用减弱了。风暴进场期间电场和场变化的时间演化在陆地和海洋上有足够的差异，值得进一步研究。这项工作显示了这些数据的质量，准确性和可靠性，并证明了海上电场测量对于KSC安全和发射相关决策的实用性。