Temporal dynamics of precipitation in an extreme mid-latitude monsoonal climate

Trends of precipitation over the twentieth century are examined by a variety of methods to more fully describe how precipitation has changed in the Russian Far East. Data used are considered to represent conditions of the extreme monsoonal climate of the high-to-mid-latitude climate of the Russian Far East region for the period 1911 to 2005. The study examines within-year characteristics of the 95-year time series. The results show variability of precipitation is high in all months, but especially so during the cold season. Trends in the data indicate that both the wettest and driest months of the year are getting wetter. There are some distinct shifts in the trend patterns. Most noticeable is a shift from positive trends to negative trends. Overall, the results show the highest twentieth century precipitation in the early 1960s and in the late 1970s, with a general decrease since the mid-1980s. This differs from trends and means for Russia as a whole. The results also show standard normals to be different from a complete record of monthly precipitation data. Further, it may not enough to use a limited period times series such as a 30-year normal to represent a steady average for a year or a season, as the mean changes through time; in particular, for a steady cold season, mean one should use the full period.