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The climatic and agroclimatic characterization of October on the territory of the Republic of Moldova
In October the average monthly air temperature is 5-6°C lower comparing to September and varies between +8°C in the Northern part and pînă la +11°C in the Southern part. The coldest October the beginning of instrumental observations was recorded in 1946, 1951 and 1976, when the average monthly air temperature varied between +4,0°C (Briceni, 1946) and +7,8°C (Ceadîr-Lunga, 1976). The warmest October was in 1896 and 1966, when the average monthly air temperature varied between +12,5°C (Briceni, 1966) and +15,1°C (Comrat, 1896). The average daily air temperature values during the month oscillated between -1..-8°C (1912) and +21..+24°C (2006). The stable transition of the average daily air temperature through +10°C is recorded between 7 and 20 October, through +8°C (beginning of the heating season) – between 18 and 31 October. The absolute minimum of the air temperature in October since the beginning of instrumental observations constituted -10,8°C (Chişinău, 29 October 1912), the absolute maximum +33,6°C (Leova, 2 October 1952). During October the frosts are recorded everywhere. The average date of the frost occurrence on the soil surface is between 1-15 October, in the air – between 12 and 26 October. Still, in the last years there weren’t recorded frosts during October (1989, 1996). The average long term quantity of precipitations in October constitutes 20-40 mm. Since the beginning of observations the highest monthly quantity of precipitations had fallen in the area of the meteorological post Codrii-2 (Lozova village, Străşeni district, 1998) – 210 mm, and the highest daily quantity – at the post Codrii-4 (Lozova village, Străşeni district, 1998) – 133 mm. The number of days with precipitations in October is in average 7-9 days. The precipitations fall mainly in the form of rain, sometimes snow. In the last years, in the second half of October the snow layer may be recorded (Briceni, 17 October 1976), but it melts very fast. The fogs may occur in October (in average 2-5 days), thunderstorms (in average a day). The hail may be also recorded in October, but its frequency is very low (in average once in 10 years). Amongst the hazardous meteorological phenomena for this month the most dangerous are the frosts that may be recorded almost yearly. The heavy rains and the storms are recorded in average once in 8 years. The probability of the torrential heavy rains in October reduces in average to once in 30 years, and of the long lasting heavy rains – in average once in 50 years. According to long term average data, until 10 October the seeding of the autumn crops finishes. The autumn wheat seeded after this term ends the autumn vegetation period without reaching the twinning phase and has a poorly developed root system not resilient to the winter frost. The autumn wheat, seeded in optimal terms, namely in the first decade of October, registers the appearance of the third leaf and in the second decade – the mass twinning. In October, the average productive humidity reserves in the arable soil layer constitute 15-25 mm. Such a quantity ensures satisfactory conditions for the development of the autumn wheat. According to the long term average data, in the second decade of October (the stable transition of the average daily air temperature through +10ºÑ) the active vegetation of the crops ends. In this period the sugar beet, potato, fruits and late vegetables harvesting is finalized. The early autumn frosts reduce the vegetation period of the grapes. Besides this, the wood ripeness process (accumulation of reserve and protection substances against the winter frosts) is disturbed. The most dangerous are the early autumn frosts with the intensity - 6°Ñ and lower, because they damage the formed buds. In the northern and central part of the republic the probability of such frosts does not exceed 10% of years and in southern - 5% of the years.
Chief MCMC T. Bugaeva Chief AFC T. Mironova
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