ИСТИНА

Report is devoted to changes of Moscow climate since the 18th century, including the end of Little Ice Age. Regular meteorological measurements started in Moscow in 1779 when one of Mannheim network stations was founded there. It operated up to 1797 and its data were printed at Ephemerides. High accuracy of measurements at Mannheim network is confirmed by high correlation co-efficient between temperature in Moscow and two closest stations (Warsaw and St. Petersburg): up to 0.82÷0.84. Different methodical questions were studied. It was found that a probable error due to thermometer installation close to the northern building wall is ±0.1÷0.2 ºС; the error due to unknown height of measurements is ±0.1; the calibration accuracy in Mannheim was also about ±0.1. Thus, a total error of the air temperature in the 18th century was not higher than ±0.3÷0.4 ºС. The mean annual temperature at that time was from 2.5 to 5 ºС whereas now it is close to 7 ºС. The minimal values at the end of Little Ice Age were extremely low: up to –39 ˚С that took place in December 17th, 1788. Later measurements in Moscow were renewed since 1810 and broken again in August of 1812 due to Napoleon invasion and terrible Moscow fire. Then they were renewed again. For the first time unknown data series of everyday measurements made by Lange in 1816÷1817 were found. It is especially interesting because the famous 1816 ‘Year Without a Summer’ was noted almost everywhere in the World as a result of Mount Tambora eruption. Nevertheless, in Moscow summer of 1816 was comparatively cool (15.8 ˚С on average) but not extremely cold. Thus, for the first time all available data about mean annual air temperature in Moscow have been collected. The power trend of the 4th degree indicates three main changes of the total tendency of Moscow climate: firstly: warming at the end of the 18th century was followed by slow cooling later; secondly: strong new warming started at the end of the 19th century; and finally: current warming has been slightly decelerated during last decades as is seen from upward convexity of the trend.