Europe Mars Bulletins
19 December 2012
Europe Mars Bulletin Vol. 20 No.12
Winter Cereal Hardening is Progressing Well

The last dekad of November presented milder thermal conditions than usual in late autumn. Weather conditions changed in the first dekad of December and real winter conditions established across Europe. Severe and frequent frost events ruled the continent. Excessive precipitation was recorded for the British Isles and in the northern Mediterranean, though precipitation was abundant in most of Europe.
Currently thick and contiguous snow covers not only northern and eastern Europe, but also central Europe and the Balkan Peninsula. According to our simulations winter cereals hardening is progressing well and so far no frost kill damage has been simulated.
Agro-Meteorological Overview
The last dekad of November presented milder thermal conditions than usual in late autumn. Weather conditions changed dramatically in the first dekad of December and real winter conditions established across Europe. Severe and frequent frost events ruled the continent. Excessive precipitation was recorded for the British Isles and in the northern Mediterranean, though precipitation was abundant in most of Europe. Currently thick and contiguous snow covers not only northern and eastern Europe, but also central Europe and the Balkan Peninsula.
Observed Temperatures
During November the temperature showed significant
fluctuation, but the overall seasonal decreasing of
temperatures was moderate and less than
climatologically expected. The last dekad of November
was warmer than usual for most of Europe with the
exception of the western part of the Iberian Peninsula,
some regions in Maghreb and the British Isles. Positive
thermal anomalies from +4 to +6°C compared to the
average temperature manifested in a wide strip between
the Adriatic and northern Baltic regions. In the last days
of November an arctic cold air intrusion started causing
sharp decreases in temperature and consequently below
average thermal conditions characterized the first dekad
of December for most of Europe, with the exception of
south eastern Europe including eastern Mediterranean.
Also the Black Sea area and southern Russia remained
warmer than usual.
After 6 December harsh winter frosts occured in central
Europe. The temperature decreased below -10°C
between the Baltic and Adriatic Sea, but in Poland, the
Czech Republic and Slovakia as low as -15°C- -18°C
minimum values were recorded. Only the southern
coastline of the Atlantic and the Mediterranean Sea
remained frost free.
The cold spell of December brought the risk of winter kill
damage. To evaluate the risk a frost kill model is run. Our
model simulates the hardening index of a crop and thus provides an estimate of the low-temperature tolerance
of cereals, taking into account plant physiology
(hardening process, i.e. transformation of the cellular
starch into glucose, thereby raising the freezing point of
the cellular liquids). In our model a fully hardened winter
cereal is considered to tolerate –18°C.
The results of model runs based on observed weather
conditions up to 10 December 2012 indicate no or slight
low-temperature tolerance of winter cereals along the
shore of southern Europe. Crops achieved medium frost
tolerance in France, Benelux countries, the UK, central
Spain, northern Balkan, Turkey, eastern Ukraine and
southern districts of Russia. Winter crops are almost or
fully hardened in an area from Germany to Belarus and
western Ukraine just as the northern agricultural zones
of Europe. No frost damages are simulated until now on
the basis of our frost kill analysis. Taking into account the
medium range weather forecast until 26 December the
period is simulated to remain free of damage.
The active temperature sum (Tbase=0°C) for the
considered time-period indicates characteristically +20-
+50 growing degree days surplus eastward of Poland-
Croatia l with a remarkable local maximum close to the
Sea of Azov and further with decerasing intensity
towards the Caspian Sea. The above average thermal
conditions on these territories favoured the
development of winter crops.
Observed Precipitation
The precipitation amount from 21 November until 10
December was above average in Germany, Bulgaria,
Romania, Turkey, Belarus, most of Ukraine and large
areas of central Russia. Excessive precipitation surpassed
150 mm in Middle England, in some regions on the
western and northern shore of the Iberian Peninsula as well as in the Alpine region, northern Italy, and along the
western coast of Tyrrhenian, Adriatic, Ionian and Aegean
Sea. These areas received a rain surplus of over 75 mm as
compared to the long term average.
Favourably plentiful rain was also recorded in Morocco
and Algeria. Hardly any precipitation (<10 mm) was measured in eastern Spain, in western Scandinavia, and in smaller districts of Austria, Hungary, Slovakia and Poland.
Primarily most of Scandinavia and the northern areas of Russia were snow covered, but starting the last days of November, more and more thick snow covered central Europe. On 10 December snow covered not only most of Scandinavia, but also areas from eastern France and Germany to Russia including Poland, central Europe, northern Italy, the Balkan Peninsula and Ukraine as well as Turkey. Snow depth has a significant spatial variability, but reaches characteristically 5-15 cm on the lowlands and exceeds 20 cm on given regions of the Balkan, Romania and Ukraine.
Weather Forecast for the Coming Days: 13 December to 22 December
Colder than usual weather is expected in eastern and northern Europe, moderate frost events in central Europe. Abundant rain is forecast for the western half of Europe and in Turkey.
Forecast Temperatures
Over the next few days, Spain, France, Benelux and western Germany will experience cumulated active temperature (Tbase=0°C) above the long term average (by 20 GDD), whereas in northern Italy, and locally in Mediterranean areas lower than usual accumulation of temperatures is foreseen. In western Europe and south of Maghreb the mean temperatures could exceed the seasonal values by +2 - +4°C. Colder than usual weather is forecast for eastern and northern Europe and also for northern Italy. Severe frost events (Tmin<-20°C) will be concentrated in northern Russia, Belarus and northern Ukraine. Spain, Portugal, southern France, Ireland and southern Italy are forecast to be frost free.
Forecast Precipitation
Low pressure over the Atlantic is going to dominate the weather over western and central Europe. Therefore abundant precipitation is forecast around the Atlantic coast, mainly in the United Kingdom, Ireland, Spain, Portugal and France, but also in western Germany, the alpine region, northern Italy and in Turkey. In these areas cumulated rainfall will exceed long term average (LTA) by 50 mm, and locally the total amount of rainfall may exceed 50 mm. In central Europe, three or four days of precipitation are expected, with cumulated values not exceeding 30 mm, which could create a few centimetres of snow cover (mainly in Germany, Poland, the Czech Republic, and Romania). During the following three to four days some snow is expected also in northern Italy and in the Balkan Peninsula. Very scarce precipitation is expected in Russia, Belarus and central Ukraine (all mainly as snow).
December 2012
Source: MARS BULLETIN – EC - JRC
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