2017 Fiscal Year Final Research Report
Study of paleosecular variation in association with dynamics of the Earth's deep interior based on dynamo theory
| Project/Area Number |
15K05270
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Multi-year Fund |
|---|
| Section | 一般 |
|---|
| Research Field |
Solid earth and planetary physics
|
|---|
| Research Institution | Kyushu University |
|---|
Principal Investigator |
|
|---|
| Project Period (FY) |
2015-04-01 – 2018-03-31
|
| Keywords | 地球ダイナモ / コア / 地磁気永年変化 / 安定成層 / 逆転頻度 |
|---|
| Outline of Final Research Achievements |
We have studied long-term/short-term geomagnetic secular variation using numerical models of MHD dynamo. Concerning thickness of a stably stratified layer beneath the core-mantle boundary, a thinner stably stratified layer is preferred to that with seismically inferred thickness, because strong attenuation of the magnetic field intensity and its secular variation through the layer is observed in numerical models. Parameter values of a paleosecular variation model derived from dynamo models show a trend similar to paleomagnetic data in spite of difference in its absolute values. The results suggest a common core dynamics in both numerical dynamos and the geodynamo determining a long-term trend such as polarity reversal frequency.
|
| Free Research Field |
地球惑星内部電磁気学
|
