Home / Standards / GB/T 46138-2025 GB/T 46138-2025 Active Grade of geomagnetic activity 地磁活动水平分级 Standard Type GBT ICS 07.060 CCS A47 Status 现行 Issue Date 2025-08-29 Implementation 2025-12-01 Responsible Dept 中国气象局 Drafting Unit N/A