The key weather and climate features in the northern hemisphere in December 2015
  Climate The key weather and climate features in the northern hemisphere in December 2015

The key weather and climate features in the northern hemisphere in December 2015

Air temperature

December 2015 proved to be a very warm one in Russia. In the whole European territory, Siberia and Altai almost every day were established record values of daily maximum air temperature. In the first decade of the month the average temperature in the south of Siberia exceeded the norm by 12-16°C, not far below the anomaly have been here in the second decade and only the third - the cold air from the eastern regions of the country came over. In Central Russia in December the thermometer rose to near 10°C of heat. Only in the east, the whole month was colder than usual. Eastern regions of Yakutia, Kolyma, Chukotka and Kamchatka experienced the frost of 50°C. As a result, in general, over the last month the average temperature in the south of Siberia were higher than the norm by 8-10°C, on European territory by 4-6°C. At the same time, in the northeast of the country they fell short of standardd by about  1-2°C. In the Volga region it was the warmest December in history, and in Central Russia - the second warmest. The distribution and size of the anomalies of mean temperature for December in the territory of Russia are very similar with the December two years ago. The only difference is that in the place of the current cold weather in the northeast of the country in December 2013 there, so as in Siberia, were large positive anomalies in temperature (+ 10°C). Therefore, December 2013 is the warmest in the annals of Russia, while December 2015 only rounded out the top five warmest.

In China, as well as in its northern neighbor Russia, last December proved to be abnormally warm. It is among the top ten warmest Decembers in the history of meteorological observations, ie since 1891. At the same time, the anomaly is substantially less than in Russia. The largest of them formed in the north along the border with Mongolia, in the northeast of the border provincial with Russia and North Korea, as well as along the Yellow Sea and the northwest in the Xinjiang Uighur Autonomous Region (+2 ... + 4°C). In the rest of the country, the average temperature for the month was also higher than normal, but less significantly. In Japan and Korea last December turned out to be much warmer than usual (by about 2-3°C), and in Mongolia - by 3-4°C.

In Southeast Asia, the average temperature for the month was above the norm by 1-3°C.

In India, the temperature stayed around the norm. Although much of the country was going in the positive background, however, there are areas where there are weak negative anomalies: Delhi, Mumbai.

Very warm weather went to Central Asia. New daily maximum temperatures were established in Turkmenistan, Uzbekistan, Kyrgyzstan and southern Kazakhstan. In Turkmenistan, the thermometer rose to the summer values of 30°C. In the south of Kazakhstan in the winter months the air warmed up to + 20°C, at a daily rate of that day about 0°C. According to local residents for the first time at this time of year lilacs blossomed.

From South Asia, only the western part of it - the Middle East have not received enough heat. In Jordan, Iraq, Iran, Saudi Arabia, Oman, Azerbaijan and particularly in Turkey, the last month was much colder than normal. Somewhere by 1-2°C, in Turkey - by 2-4°C.

A few cooler than usual was in Greece. But it is the only European country where the average temperature for the month was below normal. Everywhere it significantly exceeded it. On average, by 2.5°C, and in France, Belgium, Holland, Great Britain, Germany, Poland, the Baltic countries - by 4-6°C. Due to the warm weather in a timely manner did not open alpine ski resorts. As a result, December 2015 was the second warmest in the history of meteorological observations in the continent. Even warmer was only a distant December of 1934.

Warm European weather went to the Mediterranean coast of Africa and penetrated far in the south along the Atlantic coast. However, the central regions of the continent (Mali, Niger, Chad, and Burkina Faso) did not get its temperature norm.

The unprecedented weather was established in December in the United States and Canada. Hundreds of cities registered new temperature records, and not only subsistence but monthly. In the second half of the month, no one December day in the United States was over without the temperature record. Basically, all the same, these heat waves spread over the east and Midwest United States, as well as - southeast of Canada. In these territories, the monthly rate of temperature was exceeded by 4-8°C. On some specific days, there was the record cold in the southwestern United States. However, heat overcame cold. December 2015 in the US was the warmest in history, and one year as a whole 2nd warmest after 2012.

In Moscow, as well as in Central Russia, last month was very warm. The average temperature in December 2015 for the third time in the history of the city was positive. For the first time it happened in December 1960: the average temperature for the month reached a value of + 0.1°C. For the second time in December 2006 (+ 1.2°C), and the third time in the past month (+ 0.2°C). Thus, December 2015 was the second best, while the whole 2015 was the warmest in the history of the Russian capital. Now a new absolute maximum annual average air temperature in Moscow is equal to + 7.4°C, which is 0.1°C more than the previous record-holder, 2008.

Last year in the Northern Hemisphere was warmest in the history of regular meteorological observations on the planet, that is, since 1891. The anomaly of mean annual air temperature for the first time exceeded + 1.0ºC, which is 0.2ºC more than last year, which until this year was considered extremely warm. The first inter-annual growth was very rapid - more than 0.2°C.

In the entire history of regular meteorological observations on the planet average monthly air temperature in the Northern Hemisphere exceeded the norm by 1ºC in a total of 5 times (in January 2007, February 1998 and 2002, March 2008 and November 2010), on 2015 in occurred in 10 months out of 12. Moreover, from September to the end of the year anomaly monthly average temperature reaches + 1.1ºC.

On all continents, on average for the year it was warmer than usual. The exception was only a small area on the Atlantic coast of Canada. The largest anomaly average temperature (+ 4 ... 5ºC) was registered in the Arctic in the north of the Barents and Kara seas. Anomalies of more than + 2 ... + 3ºC cover large areas of Eurasia and North America. El Niño has affected the growth of the air temperature in the eastern Pacific Ocean, and the Gulf Stream - in the west of the Atlantic Ocean. There anomaly was over + 1-2ºC.

2015 – the second warmest in the annals of the United States, China and Europe.

In Russia 2015 is the second warmest in history. Record high temperatures retains 2007. Besides the Arctic territories mentioned above, large anomalies (more than + 3ºC) registered in most parts of Siberia and the North Urals. In the North-West, Central and Southern Far Eastern Federal Districts 2015 was the warmest in meteorological annals since 1891, and in the Siberian Federal District, repeated record achievement of 2007 and 2011.

 

The temperature of the ocean surface

In the Pacific retained the active phase of the El Niño. The anomalies of sea surface temperature (SST) in the equatorial latitudes exceeded by +2 ... 3°C. The average value of the surface temperature of the Pacific Ocean in the Northern Hemisphere of the 5th month in a row achieved an absolute maximum. Almost at all the waters from the equator to the Bering Sea monthly average SST was higher than normal, and only in the west of the temperate latitudes of Japan and Okhotsk seas, so as to the east of Japan, in December were negative SST anomaly. Noticeably higher than normal water temperature was not only in equatorial latitudes and in the east of the ocean, but also in the west - in the South China and East China Sea and south of Japan.

The average value of surface temperature anomalies of the Atlantic Ocean in the Northern Hemisphere remained at the level of recent months - about 0.5°C. Still significantly above the normal temperature of the water was in the Gulf Stream and the Gulf of Mexico (anomalies + 1-2°C), and off the coast of Europe. Much of the water area of the ocean between Newfoundland and Greenland and further away to the east was occupied by the negative SST anomalies. In some places, the water temperature was below normal by 1°C or more.

Throughout 2015 the average surface temperature of the Pacific Ocean in the Northern Hemisphere was higher than normal. This became especially noticeable in the spring, when after more than three years of a neutral phase of Southern Oscillation began a new El Niño. Gradually anomaly increased and by the end of the year in the eastern equatorial latitudes, ie where is the development of El Niño, it have exceeded a monthly basis of +3°C.  This El Nino is the second in its power and influence of atmospheric processes in the Pacific region in the modern history of meteorological observations. The championship is retained by El Nino 1997 / 98. Some processes show that the peak of the current El Niño will be passed in spring or mid-summer 2016. The situation will return to the neutral phase. The average surface temperature of the Pacific Ocean in the eastern part of the equatorial, tropical and temperate latitudes partly exceeded the norm in 2015 by 1.0-1.5°C.

Throughout the year, Gulf Stream remained abnormally warm. In its mid flow SST anomaly often exceed ± 2°C. For the whole year, average SST was over the norm by 1-2°C. It should be noted that over the same area for the whole year and in some months were formed large positive temperature anomalies. In more northern latitudes (50-55 ° N) were negative SST anomaly that may impede the advection of warm water in the northeast. On the surface of the marginal seas of the Arctic Basin, annualized positive anomalies were observed, sometimes in excess of 0.5°C.

Precipitation

Most of the territory of the Russian Federation in December received normal precipitation and above. The exceptions are the western regions of central and northern regions of the Far Eastern federal districts, where their amount for the month reached only half or less of the norm. On the contrary, the Russian North, the Volga region, the Urals and North Caucasus, Siberia and the Primorye in some areas exceeded the rate of 2 times or more. On New Year active atmospheric vortices caused heavy snowfalls in the south. In Krasnodar and Stavropol Territories, Rostov Region. and the Republic of Kalmykia per day fell up to 20 mm of precipitation. Around the same time, in southern Siberia, another cyclone has caused new daily maximum rainfall in Altai, Novosibirsk region, in the south of the Krasnoyarsk Territory and Khakassia. Here, the amount of daily precipitation in some places exceeded 25mm.

A huge amount of rainfall, 2-4 times higher than the norm, went to Kazakhstan and northern regions of Uzbekistan. While in the rest of Central Asia, they were less than half of the norm.

There was almost no rainfall in most parts of Pakistan and India. Only in the north and in the mountains in the south were rains. In the extreme south of India, they began in November and had already caused great damage to the state Tamiland. For the first three days of December in the state capital Chennai dropped 437mm of precipitation, which is more than 2 times higher than the monthly norm. Indian meteorologists believe that the rains like that have not been in these south countries for the last 100 years. In December, in the south India and in the neighboring state of Sri Lanka monthly rainfall was exceeded by 2-4 times.

In neighboring China in December were a lot of rain. The country, especially the northeastern, western and southern provinces were literally flooded. There rainfall were exceeded by 2-4 times. Downpours also touched Japan. In the capital, Tokyo, in a day resulted to 70mm of rain, and there are areas where they exceeded 200mm.

Although mainly in the Middle East it was dry, but some cyclones broke here from the Mediterranean, bringing heavy rains and snowfall in the mountains. Thus, in the first days of winter, the snow has covered northwestern Iran.

Azores anticyclone, whose center in December often located on the Mediterranean, provided the Europeans sunny and dry weather. On the continent, there were many areas where the precipitation in December did not exist. Only in the north of the UK and the Scandinavian countries, they made the norm and more. Especially it was in the United Kingdom. At the beginning and at the end of the month, torrential rains caused catastrophic floods here. In the first decade of the month, they broke out in the northwest of England and southern Scotland. At the end of the month an atmospheric storm "Eve" brought to the northwest of England rains that caused record flooding for these places.

The abundance of rainfall in December 2015 in the United States was striking. According to NOAA (US National Center for Oceanic and Atmospheric Administration) last December was the most "wet" in the country's history. Vast areas in the Midwest, in the northwest and southeast received in 2-4 times more precipitation than the norm. Almost on the entire territory from the Atlantic to the Rocky Mountains total precipitation for the month exceeded the norm. Earlier this month, heavy rains caused flooding in the state of Washington. On Christmas winter snowstorm hit the southern states of Texas, Oklahoma and New Mexico. In places where snow is an exotic, blizzard drifts piled up to three meters. Snow storm penetrated far to the south, and covered northern Mexico. Snow depth in this southern country reached 30cm. Such was not seen for the last 50 years. Surprisingly, but to the north in the Midwest instead of snow were heavy rains. In the states of Missouri, Illinois, Arkansas were the record floods that have led to numerous deaths and destruction.

In neighboring Canada, precipitation was significantly less. Only on the Atlantic coast and in the south part they dial up to norms, while in some places even more.

According to NOAA, 2015 in the United States was the third wettest in the history of meteorological observations in the country.

In Moscow, the amount of precipitation in December was 61mm. It is practically the norm. The amount of precipitation in 2015 is also a norm.

Typically, wet and dry periods are offset when calculating the annual precipitation. For example, in Russia, we can recall the March record-breaking snowfalls in the middle reaches of the Amur River, the severe floods in Ussuriysk in August, a very rainy June in the European territory. And here is the deficit of precipitation in September and October. However, the average for the year in most parts of Russia annual precipitation amount correspond to norms.

A lot of rain this year went to China, the United States, the Scandinavian countries, and that is very nice, the Sahel region, which is therefore not in need of food aid. During the summer monsoon rainfall deficit was observed in India and this was reflected in annual precipitation, finally, the most severe drought continued to dominate in California. Some experts describe it not just as strong for the whole period of regular meteorological observations, ie more than 100 years, but in the last millennium.

In Moscow, after drought of the last year in 2015 fell the norm of the precipitation.

 
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