Hydrometeorological reconstructions for northeastern Mongolia derived fromtree rings: 1651-1995

Reconstructions of annual (prior August- current July) precipitation and st reamflow, 345 yr in length (1651-1995), are presented for northeastern Mong olia based on tree- ring width data. These precipitation and streamflow rec onstructions account for 54% and 48% of the respective variance in instrume ntal data over the past 50 years. Variations in instrumental precipitation and streamflow are within the range of those reconstructed over the length of tree- ring records. However, there appear to be more frequent extended w et periods during the twentieth century. Multitaper spectral analysis revea led statistically significant peaks at 10.8 and 12.8 yr for the precipitati on reconstruction, and at 12.8 and 20.3- 23.8 yr for the streamflow reconst ruction. Similarly, singular spectrum analysis identified spectral modes of variation at 12 and 21 yr for both series. These spectra resemble those fo und for tree- ring- based precipitation reconstructions in central China as well as the western United States, and may reflect solar influences on the climate of Mongolia.