Cosmic Ray Intensity Reconstruction ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCES WHEN USING THIS DATA!!!!! NAME OF DATA SET: Cosmic Ray Intensity Reconstruction LAST UPDATE: 2/2008 (Original receipt by WDC Paleo) CONTRIBUTOR: Ilya Usoskin, Sodankyla Geophysical Observatory, University of Oulu. IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2008-013 CONTRIBUTION SERIES CITATION: Usoskin, I.G., et al. 2008. Cosmic Ray Intensity Reconstruction. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2008-013. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCES: Usoskin, I.G., K. Mursula, S.K. Solanki, M. Schuessler, and G.A. Kovaltsov. 2002. A physical reconstruction of cosmic ray intensity since 1610. J. Geophys. Res., 107(A11), 1374. Usoskin, I.G., K. Alanko-Huotari, G.A. Kovaltsov, K. Mursula. 2005. Heliospheric modulation of cosmic rays: Monthly reconstruction for 1951-2004. J. Geophys. Res., 110(A12), A12108. Alanko-Huotari, K., I.G. Usoskin, K. Mursula, and G.A. Kovaltsov. 2006. Global heliospheric parameters and cosmic ray modulation: an empirical relation for the last decades. Solar Physics, 238, 391-404. ABSTRACT (Usoskin et al. 2002): The open solar magnetic flux has been recently reconstructed by Solanki et al. [2000, 2002] for the last 400 years from sunspot data. Using this reconstructed magnetic flux as an input to a spherically symmetric quasi- steady state model of the heliosphere, we calculate the expected intensity of galactic cosmic rays at the Earth’s orbit since 1610. This new, physical reconstruction of the long-term cosmic ray intensity is in good agreement with the neutron monitor measurements during the last 50 years. Moreover, it resolves the problems related to previous reconstruction for the last 140 years based on linear correlations. We also calculate the flux of 2 GeV galactic protons and compare it to the cosmogenic 10Be level in polar ice in Greenland and Antarctica. An excellent agreement between the calculated and measured levels is found over the last 400 years. ABSTRACT (Usoskin et al. 2005): The differential energy spectrum of galactic cosmic rays in the vicinity of the Earth can be parameterized by the so-called force field model which has only one parameter, the modulation potential phi, for a given local interstellar spectrum. Here we present the series of monthly values of the modulation potential phi since February 1951, reconstructed using the data from the worldwide neutron monitor network and calibrated with precise balloon and space-borne direct measurements of cosmic ray energy spectrum. This work provides a long series of a parameter allowing for a quantitative estimate of the average monthly differential energy spectrum of cosmic rays near the Earth. A comparison with other occasional direct measurements of cosmic ray spectra confirms the reliability of the present reconstruction. The results can be applied in studies of long-term solar terrestrial relations and the global evolution of the heliosphere. ABSTRACT (Alanko-Huotari et al. 2006): We study empirical relations between the modulation of galactic cosmic rays quantified in terms of the modulation potential and the following global heliospheric parameters: the open solar magnetic flux, the tilt angle of the heliospheric current sheet, and the polarity of the heliospheric magnetic field. We show that a combination of these parameters explains the majority of the modulation potential variations during the neutron monitor era 1951 - 2005. Two empirical models are discussed: a quasi-linear model and a model assuming a power-law relation between the modulation potential and the magnetic flux. Both models describe the data fairly well. These empirical models provide a simple tool for evaluating various cosmic-ray related effects on different time scales. The models can be extended backwards in time or used for predictions, if the corresponding global heliospheric variables can be independently estimated. GEOGRAPHIC REGION: Polar PERIOD OF RECORD: 1611-2007 AD DESCRIPTION: The data are reconstructions (based on the original method [Usoskin et al. 2002], but using an updated model for the modulation potential [Usoskin et al. 2005] and updated relation between the modulation potential and NM count rate [Alanko-Huotari et al. 2007]) before 1951, and computations, using the method described in [Usoskin et al. 2005] and the data from the world NM network since 1951. Note that the data cannot be reconstructed for the deep phase of the Maunder minimum (1647-1699). DATA: Count rate of a standard polar NM (1-NM-64 at the sea-level in polar region, Pc<0.8 GV). ---------------------------- year N (104 counts/hour) ---------------------------- 1611 4.57 1612 4.42 1613 4.20 1614 4.05 1615 3.97 1616 4.11 1617 4.30 1618 4.37 1619 4.43 1620 4.46 1621 4.48 1622 4.49 1623 4.50 1624 4.45 1625 4.38 1626 4.35 1627 4.35 1628 4.41 1629 4.47 1630 4.50 1631 4.53 1632 4.57 1633 4.59 1634 4.60 1635 4.61 1636 4.61 1637 4.53 1638 4.40 1639 4.25 1640 4.14 1641 4.07 1642 4.05 1643 4.18 1644 4.34 1645 4.40 1646 4.46 ---- ---- 1700 4.76 1701 4.76 1702 4.75 1703 4.75 1704 4.74 1705 4.73 1706 4.72 1707 4.71 1708 4.71 1709 4.70 1710 4.70 1711 4.71 1712 4.71 1713 4.72 1714 4.72 1715 4.72 1716 4.71 1717 4.68 1718 4.64 1719 4.58 1720 4.53 1721 4.49 1722 4.52 1723 4.55 1724 4.56 1725 4.54 1726 4.48 1727 4.40 1728 4.30 1729 4.21 1730 4.17 1731 4.28 1732 4.41 1733 4.46 1734 4.50 1735 4.50 1736 4.43 1737 4.31 1738 4.24 1739 4.19 1740 4.28 1741 4.38 1742 4.41 1743 4.44 1744 4.48 1745 4.49 1746 4.43 1747 4.31 1748 4.22 1749 4.15 1750 4.10 1751 4.09 1752 4.22 1753 4.35 1754 4.39 1755 4.44 1756 4.47 1757 4.48 1758 4.41 1759 4.31 1760 4.24 1761 4.17 1762 4.14 1763 4.13 1764 4.24 1765 4.37 1766 4.42 1767 4.43 1768 4.31 1769 4.12 1770 4.02 1771 3.95 1772 3.92 1773 4.07 1774 4.26 1775 4.31 1776 4.36 1777 4.37 1778 4.25 1779 4.09 1780 4.03 1781 4.00 1782 4.13 1783 4.29 1784 4.35 1785 4.39 1786 4.29 1787 4.13 1788 4.03 1789 3.97 1790 3.94 1791 4.07 1792 4.24 1793 4.26 1794 4.29 1795 4.32 1796 4.37 1797 4.41 1798 4.46 1799 4.50 1800 4.51 1801 4.45 1802 4.36 1803 4.35 1804 4.40 1805 4.46 1806 4.47 1807 4.50 1808 4.53 1809 4.57 1810 4.60 1811 4.63 1812 4.64 1813 4.64 1814 4.63 1815 4.60 1816 4.55 1817 4.50 1818 4.47 1819 4.46 1820 4.50 1821 4.55 1822 4.57 1823 4.60 1824 4.61 1825 4.61 1826 4.55 1827 4.47 1828 4.36 1829 4.27 1830 4.19 1831 4.15 1832 4.26 1833 4.39 1834 4.43 1835 4.35 1836 4.18 1837 4.05 1838 3.96 1839 3.93 1840 4.07 1841 4.25 1842 4.29 1843 4.34 1844 4.39 1845 4.41 1846 4.33 1847 4.20 1848 4.11 1849 4.03 1850 3.98 1851 3.97 1852 4.11 1853 4.26 1854 4.30 1855 4.35 1856 4.41 1857 4.44 1858 4.37 1859 4.22 1860 4.12 1861 4.05 1862 4.02 1863 4.14 1864 4.28 1865 4.31 1866 4.36 1867 4.40 1868 4.42 1869 4.31 1870 4.13 1871 4.03 1872 3.97 1873 3.95 1874 4.10 1875 4.28 1876 4.34 1877 4.39 1878 4.45 1879 4.49 1880 4.49 1881 4.42 1882 4.31 1883 4.24 1884 4.17 1885 4.14 1886 4.24 1887 4.37 1888 4.42 1889 4.46 1890 4.49 1891 4.43 1892 4.30 1893 4.18 1894 4.07 1895 4.01 1896 4.00 1897 4.15 1898 4.31 1899 4.35 1900 4.40 1901 4.45 1902 4.49 1903 4.50 1904 4.42 1905 4.30 1906 4.21 1907 4.15 1908 4.11 1909 4.10 1910 4.22 1911 4.36 1912 4.42 1913 4.47 1914 4.49 1915 4.42 1916 4.27 1917 4.14 1918 4.03 1919 3.97 1920 3.96 1921 4.13 1922 4.30 1923 4.35 1924 4.39 1925 4.31 1926 4.16 1927 4.08 1928 4.01 1929 3.96 1930 3.96 1931 4.13 1932 4.30 1933 4.36 1934 4.40 1935 4.33 1936 4.17 1937 4.04 1938 3.93 1939 3.86 1940 3.84 1941 4.00 1942 4.20 1943 4.25 1944 4.31 1945 4.33 1946 4.17 1947 3.95 1948 3.84 1949 3.77 1950 3.75 1951 4.15 1952 4.22 1953 4.23 1954 4.34 1955 4.32 1956 4.14 1957 3.73 1958 3.67 1959 3.71 1960 3.75 1961 3.93 1962 4.03 1963 4.14 1964 4.31 1965 4.34 1966 4.20 1967 4.02 1968 3.92 1969 3.85 1970 3.87 1971 4.13 1972 4.20 1973 4.23 1974 4.18 1975 4.27 1976 4.30 1977 4.28 1978 4.16 1979 3.96 1980 3.86 1981 3.76 1982 3.72 1983 3.85 1984 3.91 1985 4.09 1986 4.23 1987 4.26 1988 4.01 1989 3.63 1990 3.59 1991 3.60 1992 3.92 1993 4.11 1994 4.16 1995 4.21 1996 4.29 1997 4.31 1998 4.22 1999 4.09 2000 3.82 2001 3.88 2002 3.84 2003 3.81 2004 4.03 2005 4.14 2006 4.28 2007 4.39