Construction of Digital Image Database of 44-year Synoptic Observation of Solar Chromosphere in Kyoto University

Kitai Reizaburo, kitai@kwasan.kyoto-u.ac.jp, Kyoto University
Ueno Satoru, Kyoto University
Katoda Miwako, Kyoto University
Hada Yuko, Kyoto University
Hayashi Hiroo, Kyoto University
Asai Ayumi, Kyoto University

Abstract
Solar activity is known to cyclically change in 11 years. However, the amplitude of the variation is not constant but modulated in long term span. The long term variation of solar activity is thought as one of the origin of the global warming or cooling of the earth. In Kyoto University, a continuous synoptic observation of solar chromospheres in CaIIK monochromatic light had been done during the years 1926-1969. CaIIK spectroheliographic images and white light images had been taken on daily base. All the images were recorded in photographic plates. In view of the long term span of the data and the uniqueness of full solar disk images, we think that the data is scientifically a very valuable one. Since we have a risk of aging and degradation of these old photographic plates, we have started a project to digitize all the plates and develop a digital image database for public use via IUGONET ( Inter-university Upper atmosphere Global Observation NETwork ) system. Our plan of the project consists of six stages. (1) Compilation of meta-database and its publication. (2) Digitization of all the plates and development of image database. (3) Visualization of long term solar chromospheric variation. (4) Measurement of solar plage area and brightness. (5) Comparative study between variations of sunspot number and plage activity. (6) Study on the long term character of terrestrial upper atmosphere heating with the solar plage activity as a proxy of solar EUV irradiation. In the present paper, we will give the basic plan, the present status of our project and some preliminary scientific results.