Typhoons, scorching hot weather and other disastrous or extreme
weather will be more common in the city this year than last, the
Shanghai Meteorological Bureau forecast yesterday.
Average temperatures in the city for the year will be slightly
higher than the average of 16.2 degrees Celsius recorded over the
past 10 years, the bureau said. The number of days with highs
topping 35 degrees will also be higher than normal, according to
the forecast.
Precipitation levels will be close to the average over the last
decade of 1,190.8 millimeters, including the June to September
flood period, which will receive a normal amount of rain - close to
the 642.2 millimeters average of the past several years.
The bureau will release a specific forecast for the year in
May.
Last year was relatively free of disastrous weather in the city,
with Shanghai receiving a long, hot summer and a short, wet fall,
the bureau said yesterday as it released a list of the 10 main
weather phenomenon in the city during 2006.
High temperatures
The average temperature in the city last year was 18.3 degrees,
2.1 degrees higher than normal. That was the highest average
temperature recorded in the city since records were first kept in
1873.
Longest summer
Shanghai had its longest summer in 51 years last year, running
from May 20 to October 23. The summer saw 27 days with highs
topping 35 degrees, 18 days more than the average over the past 10
years.
The average temperature during July and August was 30.1 degrees,
2.3 degrees higher than the average for recent years. That was the
highest average recorded since 1873 for the same period.
Late autumn
Autumn didn't arrive in the city until October 23, its latest
entrance in 134 years. The season arrives after five consecutive
days with average temperatures below 22 degrees. The average
temperature in October was 22.3 degrees, the highest ever recorded
in the city.
The warm weather was great for flower lovers in the city, as
osmanthus, chrysanthemums and orchids went into blossom at the same
time.
Earliest typhoon
Typhoon Chanchu affected the city from May 17 to 19, bringing
heavy rains and strong winds. It was the earliest point of the year
for a tropical cyclone to hit the city in history.
Cold front
A strong cold front entered the city on March 12, dropping
temperatures by 10.3 degrees within two days. The strongest cold
front of the year damaged some crops.
Dry plum rain season
The city had a relatively dry and hot plum rain season, which
lasted from June 13 to July 12. The city received only 183.8
millimeters of rain during the period, far less than the average
244.4 millimeters in recent year. During the plum rain season, the
city suffered through seven days with highs topping 35 degrees,
second only to 1917 for the same period, which had nine such
days.
Lightning strike
Lightning strikes were the most serious weather phenomenon to
hit the city last year. Five people were killed and one was injured
by lightning. Strikes also destroyed the communication equipment at
a satellite earth station as well as 620 household electrical
appliances.
November rain
The city had much more rain in the past fall than average for
the same period. From November 16 to 30 the city received 136.6
millimeters, almost four times the average over recent years. The
rain damaged many crops, especially rice and wheat.
Haze and fog
The city had six hazy days last year, about two or three more
than normal. It also had 14 foggy days, which affected the city's
air quality, visibility, and traffic.
In the city, nearly 100 flights delayed because of haze or fog
last year, and highway and elevated roads were closed for 13
times.
Haze and fog were mainly caused by warm weather and pollution
from vehicles and factories.
Fog: The term is used when visibility is one kilometer or less,
the relative humidity is 95 percent or more and atmospheric
obscurity is caused by suspended microscopic water droplets or wet
hygroscopic particles.
Haze: The term is used, whatever the horizontal visibility, when
the relative humidity is less than 95 percent and visibility is
reduced by very small, dry, solid particles suspended in the
atmosphere.
Solar flare
Although the solar flare eruption on December 13 and 14 did not
have much effect on the Yangtze River Delta, the electron density
of the area soared to around 17 TEC units - a measure of electors
per square meter. The eruption, which was the most serious since
1957 in low solar activity years, unleashed enough radiation to
disrupt radio communications in other parts of the country,
including the provinces of Guangdong and Hainan, as well as the
municipality of Chongqing.
Solar flares: A solar flare is a tremendous explosion on the sun
that happens when energy stored in "twisted" magnetic fields,
usually above sunspots, is suddenly released.
In a matter of just a few minutes they heat material to many
millions of degrees and produce a burst of radiation across the
electromagnetic spectrum, including from radio waves to x-rays and
gamma rays.
(Shanghai Daily January 12, 2007)
