Research On The Temporal-spatial Distribution And Regional Characteristics Of The Geomagnetic Activity Index R_H

Geomagnetic activity has increasingly important influences on human beings. Severe disturbances of geomagnetic field have adverse effects on satellites, communicate, navigation system, electric power and oil pipelines. And then the national economy will suffer huge losses. Indices which are used to describe the level of geomagnetic activity have been created one after another. The study on geomagnetic activity and index has great significance in science and practical value in business. There are still a lot of problems in K index, Kp index and Dst index, though they are widely used now. Considering the requirements for resolution and timeliness of the space weather operation, the range of hourly H component index (rH) with high resolution, which is near-real-time, is been studied. To reflect the local disturbances of geomagnetic activity better, regional geomagnetic index is been designed for China.The observational data from Geomagnetic Network of China, International Real-time Magnetic Observatory Network (INTERMAGNET), and Data Centre for Meridian Space Weather Monitoring Project, also the K index, Kp index, and Dst index from World Data Center for Geomagnetism in Kyoto are organized at first. With the data of geomagnetic observatories both in China and abroad in2001-2013, both temporal and spatial variation characteristics of rH index are analyzed. The results show that the rH has a periodic change in27days, which is the solar rotation cycle. Although no significant seasonal variation is observed in rH, it is also shown that the average of rH in spring and autumn is greater than in summer and winter. For spatial variations, rH increases with the latitude, but the form of these changes are very similar in a broad range of latitude. There are some obvious difference in amplitude and morphology of rH during geomagnetic storms, and the time when rH of different station reaches storm level is also different. We also find that rH has the feature of dusk-dawn asymmetry.At last, the14geomagnetic observatories in China are divided into7regions by using K-means clustering algorithm based on the similarity measurement, the residual index (Ra) of rH index between each two observatories. Then the regional rH index (Rr) of each region is calculated by linear weighted sum method. Comparison with the observational data of H component and other Global geomagnetic activity indices, such as Dst, SYM-H and Kp, indicates that Rr can reflect the regional geomagnetic disturbance effectively.