Global Climate Changes and Humidity Variations Over East Europe and Asia by Historical Data

Historical, or documentary, data serve as an important independent source of information on past climates, including humidity, precipitation, and river runoff. These data, covering time scales of several hundreds to several thousand millennia, fill in the gap between data of direct, instrumental, observations and paleodata. Extensive data bases of such proxies have been compiled from the Chinese, Russian, and other historical sources. However, a variety of human-induced factors (national mentality, wars, etc.) that affected registration of climatic and hydrological events often prevent scholars from application of such data to the quantification of past climate changes.An approach is proposed to quantify changes in mean annual air temperature, precipitation, and river runoff derived from historical data on extreme events Use of a fraction of climate extremes of a certain kind among all extremes registered during the time interval (usually several decades) eliminate partly human-induced factors. Application of this technique is exemplified by the records from East European Plain covering the last millennium.A qualitative analysis of climate changes during the last 2,500-3,000 years over the whole extratropical Asia and East Europe is also presented. Major phases of thermal changes during this period. Iron Age cooling. Medieval climate optimum, and Little Ice Age, can be traced over the whole Eurasia, but they are usually aged from earlier times in eastern sectors of the continent The similar pattern of set in characterizes periods of increased precipitation and river runoff.Negative correlation of temperature and humidification anomalies appears to be the important feature in the arid sectors of Eurasia, whereas in most other regions correlation of these parameters is usually positive, hut less intensive. As a first approximation, eight regions can be discerned in the extratropical Asia and East Europe by the differences in their humidity response to the large-scale changes in air temperature during the last millennia.