1Jiang Yangming
1. Introduction
We use MODIS data to inverse the temperature and its spatial
distribution in China over the past 10 years. And use the
meteorological data to reconstruct the winter temperature anomaly
time series of the urban, suburban, countryside and meteorological
stations’ neighborhood in the last 60 years. We find that
(1) meteorological observatory's temperature records may be
affected by urban heat island effect;
(2)China temperature fluctuated in the last 60 years and the small
fluctuated cycle is about 7 years;
(3)On the decade-scale, the biggest decadal temperature increased
is 1990s; Although the early 21st century's temperatures is still
in the warm period, but it has emerged the downward trend.
2 The Data Used in temperature inversion
China Winter Temperature is mainly Controlled by the Siberian cold
air, so the temperature’s change is more consistent. We can use
winter temperature as the indicators of climate change.
We use the 202223293132 bands of MODIS from 2000-2010 to inverse
the temperature. The Coordinate system is WGS84, and the spatial
resolution is 0.05 degree. We also use Chinese 722 meteorological
stations' temperature records 1951-2009 in the study.
Using all weather stations' monthly data 1951-2009 to establish
November, December, January and Winter average temperature series.
We systematically analysis each month's temperature trend and the
winter temperature trend, then revise the temperature records.
Specific steps are as follows:
1Converse the 722 weather stations' monthly average temperature
records to monthly average temperature anomaly data
1951-2009.
2Test the conversed temperature data. If the monthly temperature
anomaly is larger than +5 or less than -5 , we will analysis the
credibility of the stations' temperature records and correct
it.
Reconstruct the winter temperature anomaly time series
(1)Change Meteorological stations' temperature records into grid
temperature data: We mainly use the DEM which spatial resolution is
0.05°×0.05° and the temperature records 1951-2010. The main method
is Kriging interpolation.
(2)Use MODIS data to inverse the winter average temperature and its
spatial distribution 2000-2009.
(3) Correct the 1951-2009 temperature which obtained by
interpolated the meteorological records based on the temperature
spatial distribution matrix .
Winter temperature distribution map of 2000 year based on
interpolation
Winter temperature anomaly trend in China
(3-point sliding average curve) from 2000 to 2010
We use MODIS data to inverse China winter temperature anomaly
trends 2000-2009, and find that temperature records affected by
Urban heat island effect.
Greenland temperatures change chart and the temperature changes in
China (Zhu Kezhen, 1973)
4.2 Centennial Temperature Variation Analysis
4.2 Centennial Temperature Variation Analysis
(1) The first two thousand years in Chinese historical five
thousand years, the annual average temperature was 2 degrees
Celsius higher than now.
(2) Cold period started in the first millennium BC (Late Yin, early
Zhou Dynasty), four centuries AD (the Six Dynasties), one thousand
two hundred years AD (Song Dynasty) and one thousand seven hundred
years AD(the Ming and Qing Dynasty). The Han and Tang dynasty was
relatively warmer.
(3)In each 400 to 800 years, we can separate 50-100 years cycle as
a small climate variation cycle, the temperature range form 1 to
0.5 .
4.3 Decadal Temperature Variation Analysis
Apply the cosine of the grid's latitude as weightCalculate
1951-2009 China decadal temperature anomaly trendfigure 6,and find
that compared to 1951-1980 average temperature:
(1) 1950s and 1960s is the cold period;
(2) 1970s -2009 is a warm period, 1990s is the warmest decade of
the 20th century the maximum of 20th century’s interdecadal
temperature range is 0.27
(3)Although the temperature of the last decade is still higher than
the 1951-1980 average temperature, but the temperature has a
downward trend.
Fig6 Interdecadal temperature anomaly trend in Winter since 1950s
in china
4.3 Decadal Temperature Variation Analysis
4.4 Annual temperature variation analysis
Fig7 Chinese winter temperature anomaly change trend from 1951 to
2009
Fig8 Winter temperature anomaly trend of Chinese cities since
1950s
Through comparative analysis two graphs we know that:
(1)There is 30 years whose winter temperatures higher than the
1951-1980 average temperature has 30 years, and 29 years’ less than
the average.
(2) Chinese temperature fluctuated over the past 60 years and the
small fluctuated cycle is about 7 years;
(3) Through the regression analysis on the temperature anomaly, we
know that in the last 60 yearsChina temperature rise about 0.2 city
temperature rise about 0.3 City temperature is higher than
countryside4.05
(4)Since 2000, the temperature variation amplitude decreasedand
temperature has a downward trend.
Summary
(1) The "Warming" in the last 60 years is a normal phenomenon of
climate change.
(2) Human activities has some impact on the temperature in some
region, such as the urban and suburban is significantly warmer than
in countryside.