During
this winter, mean surface air temperatures were 0.5¡æ above normal in China and
domain difference is very obvious. Mean surface air temperatures were 1¡æ below
normal in Northeast China and most of Inner Mongolia and western Xinjiang.
Positive temperature anomalies above 1¡æ were in most of the Tibet Plateau and
Yunan, western Sichuan and southeastern South China, the central value above
4¡æ in part of the Tibet Plateau. In this season, rainfall totals were 30%
~200% more than normal in the northern Northeast, most of the Northwest, regions
from the southeastern Tibet Plateau to southern Sichuan, with maximum above 200
in southern Xinjiang. Meanwhile, precipitation totals were 30~80% less than
normal in the southwestern and northeastern Tibet Plateau, most of North China
and parts of South China.
During
this winter, mean surface air temperatures anomalies were 2¡æ below in most of
mid-latitude Eurasia with 4¡«6¡æ below normal in central Russia. Positive anomalies above 1¡æ were
the Tibet Plateau, northern South Asia, coastal north-central Russia,
north-central U.S.A and Alaska, central and eastern Australia, with central
value above 4¡æ in the Tibet Plateau.
In
the winter, rainfall totals were 30% more than normal in most of mid-latitude
Eurasia, western Australia, northwestern U.S.A and parts of Argentina, with
maximum above 200% in parts of China¡¯s Xinjiang. Precipitation totals were
30~80% less than normal in most of Russia, western Europe, most of South Asia,
southern and central America, eastern Australia. Meanwhile, no rainfall was
observed in northern South Asia during this season.
General Circulation Features
Northern
Hemisphere: During
the winter, the mean 500hPa geopotential height field exhibited 3-wave pattern.
In the height anomaly field, above 4 dam anomalies controlled in the regions
from northern North Atlantic Ocean to the North Polar Region, the central North
Pacific, regions from West Asia to Central Asia, with central values above 12
dam over the North Atlantic Ocean to the Polar Region. Heights were near normal
in the rest regions. Subtropical highs both in the northern hemisphere and in
the Northwest Pacific were stronger and larger than normal.
Southern
Hemisphere:
In
the
mean 500hPa geopotential height anomaly field,
negative anomalies mainly covered latitudes between 40¡ãS~60¡ãS,
with anomalies below -4 dam over the ocean south to Australia, the ocean south
to Africa and south-central South Pacific. Meanwhile, 4 dam above-normal heights
were observed over parts of the South Polar Region, south-central South Indian
Ocean.