Revised version
Twentieth-century climatic warming in China in the context
of the Holocene
Shaowu Wang1), Daoyi Gong2) and Jinhong Zhu1)
1) Department of Geophysics, Peking University, Beijing, 100871, P.R. China
2) Key Laboratory of Environmental Change and Natural Disaster, Institute of Resources Science,
Beijing Normal University, 100875, P.R. China
Submit to The Holocene
Postal address
Shaowu Wang
Department of Geophysics
Peking University
Beijing 100871
P. R. China
Email. swwang@pku.edu.cn
Fax. 86-10-6275-4294
Telephone. 86-10-6275-5568
1
Abstract
Development of an annual mean temperature series of China for the period of 1880-1998 indicated
that 1998 was the warmest year since 1880. During 1998 temperature was of 1.38C higher than the
normal (1961-1990). Annual mean temperatures of China were found using the weighted (according
to the size of regions) average of ten regional series, which covered the whole land area of the
country from Xinjiang and Tibet in the west to Taiwan in the east. Gaps of temperature observations
were filled by using of ice core 18O and tree-ring data for three regions in the west, and
documentary data for seven regions in the east. Since 1951, only observational data were used.
50-year mean temperature anomalies were found from 9th to 20th centuries on the basis of ice
core 18O and tree-ring data in west China, and documentary data in east China. The series do not
show any consistent warm period in west China during the Medieval Warm Period (AD 900 to 1300).
But, temperatures in east China in AD850-1099 and 1200-1299 were about 0.2 C higher than the
average for the last years. Century mean temperatures of China combining west and east regions
from the 9th to 20th century showed that the 20th century was 0.4C warmer than the mean of the
whole period. Temperatures of 9th, 10th, 11th and 13th century were only slightly (0.05-0.10C)
higher than the average. Therefore, the 20th century seems the warmest one in China for the last
millennium or more.
However, the last millennium was not the warmest one in comparing with others for the last ten
millennia. Ten regional temperature series from 10kaBP to the present were analyzed with the same
time resolution (250a) and identical normal (1880-1979). Gaps in a few series in the last millennium
or so were filled by the data carried out in an early paper (Wang et al., 1998a). Average temperatures
were also found on the basis of area weighting of regional series. It shows that the Megathermal was
manifested well in China, temperatures from 8.0 to 3.0kaBP were of 1.5 to 2.0C higher than the
present.
Studies on the relationship between temperature and precipitation indicated that no consistent
correlation was found. However, warm-dry was dominated over warm-wet climate in north China,
but the opposite is true in the very south and in the west. In east China, the 20th century probably
was the driest one during the last millennium. Severe droughts occurred in 20 of the 100 summers of
1900-1999, but the mean frequency was only 10.6 per century.
Key words: Modern Climate Warming, Medieval Warm Period, Megathermal, Climate of 20th
Century in China.
Introduction
Global climate warming has been broadly identified in 1990s (Christy et al. 1994, Jones 1994,
Barnett et al. 1996, Kaplan 1998). Investigations of global mean temperature changes for a few
hundred years or more, by using of proxy data, provide important background knowledge for
understanding of the warming process, including the timing and intensity of it (Jacoby et al. 1994,
Mann et al. 1998, Jones et al. 1998). However the warming, as widely acknowledged, varies
significantly from region to region over the globe. Therefore, studies on the climate warming at the
regional scale, as over China, has meaningful importance. It will improve understanding on the modern
warming, and offer a new possibility to test the theoretical results of numerical simulations with GCMs
(General Circulation Models) for the enhancement of greenhouse effect on the regional scale.
Unfortunately, regional characteristics of the warming was less well examined in China due to the
lack of long enough and homogeneous temperature series. Recently, application of proxy data enable
us to reconstruct different time scale of temperature series in China; (1) Annual mean temperature
series of China for the period of 1880-1998 (Wang et al., 1990a). (2) Decadal mean temperatures were
found by using documentary data in north and east China for the period 1380s to 1980s (Wang 1990c,
Wang 1991). (3) 50-year mean temperature changes were examined on the basis of ice core, tree-ring
and documentary data for the last millennium, to study the characteristics of the Medieval Warm
Period and the Little Ice Age in China (Wang et al., 1998a). (4) Temperature changes for the last 10ka
were investigated by analyzing much pollen data, which has been extensively studied in China during
the last twenty years (Wang and Gong, 2000). All of these studies provided consistent and
homogeneous temperature series of China. Therefore, for the first time there is an opportunity for a
rational assessment of modern climate warming in China.
In this paper, the modern warming is examined in the second section. Then, the warming in the
20th century is compared with that in the Medieval Warm Period and Megathermal in the third section.
Meanwhile, a question often asked in studies of climatic change is do dry or wet conditions accompany
the warming? This question has been argued for long time and no satisfying answer is obtained till
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now. Identification of the warming in 20th century and in the Medieval Warm Period, and examination
of summer rainfall patterns for the last millennium (Wang et al., 1993) facilitated assessing the
problem put forward above. Preliminary results are given in the fourth section.
The Modern Climate Warming
Wang et al., (1963) had proved a significant warming trend in China during the first half of 20th
century on the basis of temperature observations at a few stations. It has been indicated that the
warming trend was mainly limited to the eastern coast region. Temperature changes in inland areas
showed quite different characteristics to the coastal region. However, temperature observation inland
had often been interrupted by wars. These prevented a full understanding of climatic change in China.
In view of the serious gaps in observation series, the Weather-Climate Section of Meteorological
Institute in China has compiled and issued a series of temperature-grade maps of 1911-1980
(Weather-Climate Section, 1984), where temperatures were transformed into grades. The procedures
used in transformation were as following: firstly, temperatures for each month and for each station
were arranged according to their values. Then, the top 12.5% was denoted as grade 1,and next 25% as
2. Grade 3 and grade 4 also cover the next 25% separately. Temperatures in the lowest 12.5% were
grouped into grade 5. Therefore, grade 1, 2, 3, 4 and 5 relate to much above, above, normal, below and
much below normal. Finally, monthly temperature-grade maps were drawn from January 1911 to
December 1980. Greater spatial consistency is observed on these temperature-grade maps than
temperature anomaly maps. It makes relatively easy to interpolate the grads when they were obscure
for the gap of observations. Fortunately, the gaps usually appeared only in single station, but did rarely
cover an area larger than a region in any monthly map. This depends on the maximum collection of the
observations, including that was made under the war (Weather-Climate Section, 1984). Before 1911,
observations were available for a few stations then the temperature-grade maps did not extend back
more. Finally, regional monthly mean temperature grade (no integer figures) were calculated for
Northeast, North, East, South, Central, Southwest and Northwest regions, according to temperature
grads in 5 to 7 key stations in each region. These series provided important information about the
climate warming in China, though Xinjiang, Tibet and Taiwan were not included in the analysis.
Later, Wang (1990a) and Lin et al.,(1995) have extended the annual mean temperature series of
China to 1880 or early. The number of stations used in the analysis varied from less than 5 in 19th
century to 160 or more in second half of 20th century. There are great inhomogeneities in the series for
the coverage was poor and variance was large in early period. It increased the uncertainty in
assessment of the modern warming in China.
Recently, a new temperature series of China was constructed. Firstly, ten regional temperature
series were found which cover the whole mainland and island area (Table 1). Then a temperature series
of China was formed by averaging the ten regional series with weighting according to the size of the
regions. Data sources used in this study are outlined in Table 1. The time period of 1880-1998 was
divided into three parts; 1880-1910, 1911-1950, and 1951-1998 according to the availability of
observational data. In the later part (1951-1998), a regional temperature series was formed by the
average of the temperatures for five key stations for each region. Totally, temperature observations for
fifty stations were used for ten regions. This kind of data source was denoted as O in Table 1. In the
second period (1911-1950), regional temperature grades were applied, and transformed into
temperature anomaly according to the relationship between temperature grade and anomalies for seven
from ten regions, as the grade series are available. For the other three regions; ice core 18O data of
Guliya (Yao et al., 1996) were used in Xinjiang, for it has a correlation coefficient 0.2 to 0.4 with
annual mean temperature observations over the Xinjiang region. These 18O data were adopted as a
regional index, for it correlated with a series of stations well. Therefore, it was not transferred to any
single station. In Tibet, tree-ring data were closely correlated to temperature observation over
Qinghai-Tibet Plateau (Kong et al.,1997). Temperature observations are also available in Lasa for
some years in this period. Therefore, gaps in observed series were filled with tree ring data.
Methodology of transform the later to temperature anomalies was the same as used in Xingjiang. For
Taiwan observational data are available, so proxy data was not used. In the early period (1880-1910),
observations are available for at least one central station in each from the first five regions. It is
denoted as Os in Table 1. In this case when temperature variance is usually greater than that averaged
for five stations, it was reduced a little according to the relationship between number of stations used in
averaging and size of the variance. For Xinjiang and Tibet, ice core (Yao et al., 1996) and tree-ring
(Kong et al., 1997) data were applied in a similar fashion as in the second period. Ice core 18O data of
Dunde (Yao et al., 1990) were used for the Northwest, since it correlated closely to the temperatures of
that region. Transformation of 18O data of Dunde was made as for Xingjiang. For the Middle and
Southwest regions, historical documents were used. For Taiwan, observational data was not enough, so
3
historical data were also incorporated. The usage of historical documents will be described in next
section. The only thing to be noted here is that both ice core and tree-ring data were transformed into
temperature anomaly as following: (1) Normalize temperature and ice core or tree-ring series for the
period of 1961—1990. (2) Normalize the ice core or tree-ring series before 1961 by using of the
normal and variance of 1961-1990. (3) Multiply the variance of temperature for 1961-1990 to the
normalized anomaly of ice core 18O or tree-ring width, and get temperature anomaly. Finally, ten
regional temperatures were averaged according to the areas of the region (last column in Table 1),
forming a temperature series for the country. Areas of the regions are decided according to the
correlation coefficients between temperatures averaged for key station and that for each 11
longitude and latitude grid box over China (Wang et al., 1998b).
Fig.1 illustrates the regionality and location of the stations. The numbers show the order of ten
regions. Black dots or circles indicate geographical locations of the stations with or without
temperature grade data. Full squares show the key stations. Stars denote the central station for each
region. Dunde and Guliya are marked with arrow. Fig.2 gives annual mean temperature anomalies for
1880-1998 referred to the normal of 1961-1990. Positive anomalies were shaded. The curve shows
low-pass filtered result. It is indicated in Fig.2 that the warming in the 20th century started in 1920 and
was interrupted in 1950’s and 1960’s. Temperature increased persistently since 1969. However, it was
still lower than that observed in 1940’s. A new record was set in 1998, temperature anomaly was
1.38C. It is much higher than the previous ones in 1942 and 1994, where the anomaly was the same of
0.92 C. The year of 1998 was the warmest since at least 1880. Preliminary analysis of the
observations from January to August of 1999 in China indicated that it is impossible to make a new
record in 1999. So, the 1998 was probably also the warmest year of the 20th century.
The 1990’s of China also seem to be one of the warmest decade in the 20th century, though the
mean temperature anomaly of 1990-1998 (0.58C) was a little less than that of 1940-1949 (0.62C).
Reconstruction of decadal mean temperature anomalies of ten regions for last 400-600years proves that
mean temperature of 1990-1998 was higher than any other decade in Northeast (1), North (2), East (3),
Taiwan (5) and Xinjiang (9) regions. But, in South (4), Central (6), Southwest (7), Northwest (8)
and Tibet (10) regions, mean temperature of 1940’s was higher than 1990’s (1990-1998), (Wang et al.,
1998a).
Was the 20th century the warmest during the last millennium?
Decadal mean temperature anomalies of North and East China (region 2 and 3 ) for the period of
1380’s-1870’s have been reconstructed by using documentary data (Wang 1990c, Wang 1991).
Procedures of the reconstruction are briefly introduced as following;
(1) Many cold events have been recorded in county gazetteers. Calibration of cold events against
instrumentally observed temperature enables us to assess seasonal temperature anomalies for each type
of the events.
(2) Cold events are grouped into three categories, in which the seasonal temperature anomaly was
about –0.5C, –1.0C, and –2.0C, the latter were expressed as a non-dimensional quantity of –0.5,
–1.0 and –2.0, and named as the Severity Index (Table 2).
(3) There were some cases, especially in 17th and 19th century, severity of the cold events seems
much greater than what has happened in the 20th century, Cold events also had greater geographical
coverage. Such extents have not found in the last one hundred years or more. The Severity Index of
this kind of the event was considered as –3.0. Meanwhile, there are also a few records of very hot
summers or mild winters. It is very important to include these in analysis, especially for revealing the
warm decades. Therefore, a Severity Index of 1.5 was applied for very hot or warm seasons.
(4) Decadal Severity Indices were found by summation of the ten years included in the decade.
Correlation coefficient was calculated between decadal mean temperature anomalies for 1880’s-1970’s
and simultaneous decadal Severity Indices. It varied between 0.6 to 0.7 from region to region. This
relationship was used to transform the Severity Indices to decadal mean temperature anomalies.
Temperature anomalies were reconstructed for decadal rather than for each year because usually
documentary records are available only in about 10% to 30% of the seasons examined, so it is
impossible to estimate temperature anomalies year to year and season to season.
Finally, decadal mean temperature anomalies were averaged for four seasons to find the annual
mean. Fig. 3 shows decadal mean temperature anomalies from 1380’s to 1990’s (1990-1998) for north
(a) and east (b) China, and for China (c) as a whole. The latter extended only to 1600’s, as temperature
series for other regions were shorter especially in northeast China. Before 1380’s in some regions and
1600’sin some other's documentary data were not enough to ensure get a reliable indices for ten year
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period, then decadal mean temperature anomalies were not reconstructed.
Three cold spells (I, II, and III), which characteristics the Little Ice Age in China are clearly
manifest in Fig.3. It has been found that there were two cold stages (1 and 2) in each of the cold spells.
Mean temperature anomaly for each of the stages is given in Table 3. Reference period here is
1880-1979. Temperature anomalies of 1920’s-1940’s, the warmest 30 consecutive years in 20th
century, were shown in Table 3 for comparison. Fig.3 and Table 3 suggest that the 20th century was
significantly warmer than at least the four or five previous centuries in China. Temperatures in the
warm spell of the 20th century (1920’-1940’s) were about 1 C higher than those for the cold stage, for
example, 1620’s-1690’s during the Little Ice Age.
However it is well known that a warm period, so called the Medieval Warm Period (MWP)
probably occurred during AD 900-1300 over a great deal of land area of the earth, though the intensity
and timing of warming climate is still debated (Hughes and Diaz 1994). Therefore, assessment of the
characteristics of modern warming in China is critical for answering the question:“ Was the 20th
century the warmest during the last millennium?” Unfortunately, many of items of documentary data
are considerably reduced in early period. All together 489 items of disaster records, related to
temperature anomalies, have been identified for whole China. Data sources are outlined in Table 4,
which have been compiled in recent years mainly on the basis of Dynastic Histories. Considering the
availability of data, one is unable to reconstruct seasonal temperature series from region to region, and
has to reduce the time resolution to 50 years. Consequently a unified temperature series of 50-year
mean anomaly was built for east part of China (1st to 7th regions in Fig.1). The procedure used was the
same as in reconstruction of decadal mean temperature series. The only change was that the omission
of category 0.5 from cold event identification. A correlation coefficient of 0.9 between the Severity
Index and 50-year mean temperature was calculated for the period 15th to 20th centuries. Then the
Severity Index was transferred to temperature anomaly from 9th to 14th centuries.
In west China, the only data source that could be used in analysis was ice core and tree-ring.
Wang et al. (1998) have reconstructed decadal mean temperature anomaly series for the last
millennium for 8th to 10th regions (Northwest, Xinjiang and Tibet). Now, these three regional series
were extended to AD 800, combined to a single one, to form the 50-year mean anomalies of the west
part of the country. Simple average of the two series was calculated, for the size of area occupied by
east seven regions (0.48) and west three regions (0.52) is nearly the same. The anomalies are
referenced to the average of 1880-1979 in Fig.4, while broken lines show the average for whole period
from the 9th to 20th centuries. Reconstruction of temperature series indicated that the 20th century was
indeed the warmest one over China as a whole during the last millennium.
However, temperatures
in the Medieval Warm Period were only a little higher than the average of last 1200 years in east part,
but were much lower in west part of China.
However, it is worth noting that the last millennium was not the warmest one in the Holocene in
China. Study on temperature changes for last 10ka using pollen series indicate that climate in the so
called Megathemal (3.0 to 8.0ka BP) was considerably warmer than the present (1880-1970). Table 5
shows the location of these pollen data sites. Maximum anomaly varied between 1.5～2.0℃ (Fig.5).
Therefore, the climatic warming of the 20th century still lay in between the limitation of natural
variability, no matter what the warming attribute: anthropogenic or natural.
Does dry condition predominated when the climate was warm?
It is often stated that the climate in China during the Megathemal (3.0 to 8.0kaBP) was warmer
and wetter than the present. This point of view has been supported by pollen and archaeological
evidence (Shi, 1992; Shi Zhang,1996). However, experience in monthly to seasonal climate predictions
suggested that temperatures usually were higher than the normal when drought predominated.
Therefore, the relationship between temperature and precipitation anomalies in climatic change is
examined here by using of observations and reconstructed climatic series.
Fig.6 shows the correlation between annual mean temperatures and total precipitation calculated
on the basis of a 160-station data set for the period of 1951-1998. Negative correlations dominated in
the north and northeast part of the country. Therefore, warm-dry conditions predominated in north
China over warm-wet. However, positive correlations were found in the southeast part of the country,
inferring the predominance of warm -wet conditions.
This relationship was tested by using climatic data for an earlier period. Fig. 2 indicated that the
30-year period of 1920-1949 was the warmest during 1880’s to 1990’s, and 1880-1909 was the coldest.
Therefore, 30-year mean anomalies of annual total precipitation for both warm (1920-1949) and cold
(1880-1909) periods and the difference between them are given in Fig.7, where a 35-station data set of
annual precipitation was used, which was reconstructed by combining the observations with
documentary evidence (Ye et al., 1998; Wang et al. 2000). Fig.7 shows that warm-dry and cold-wet
5
predominated in north part of the country, but warm-wet and cold-dry hold a dominant position in
southeast.
Similar character in the relationship of precipitation to temperature was further confirmed by a
summer rainfall type chronicle, which was built in 1981 (Wang and Zhao, 1981), extended to AD 950
in 1993 (Wang et al., 1993), and updated to 1999. Six types were identified according to empirical
orthogonal function(EOF) analysis, the first three EOFs explain 40%-50% of the total variance. A brief
description of rainfall characteristics is given in Table 6.
Frequency of summer rainfall types in Table 7 indicated that type 2 and type 5 occurred more
often in the warm 30-year period (1920-1949), implying droughts in the north or over whole area of
east China, while no type 1 was observed. On the contrary, in the cold 30-year period type 1a and type
4 were found to be more frequent, inferring floods occupied the whole east part of the country or
predominated over the North. Summer rainfall makes about 40%-50% contribution in south and
60%-70% in north to the total annual precipitation, so the rainfall variability in summer characterizes
to a great extent the climatic change of precipitation, especially in the east part of China.
Frequencies of summer rainfall types during the Medieval Warm Period and the Little Ice Age
were compared to the normal (AD950 to 1999). A contrast of a greater frequency of type 2 and 1b in
MWP and of type 4 and 3 in LIA is clear. It proves again that warm/dry (or cold/wet) climate was
predominant in north and warm/wet (or cold/dry) climate in southeast China. See Table 8.
Predominance of warm-dry conditions in north part of China in the Medieval Warm Period should
be attributed to the natural climate variability, for in that time anthropogenic impact was still negligible.
However, precipitation in the north part of China also decreased significantly in warm decade of 20th
century, in 1920-1949 (Fig. 7a).
Recently Shi et al., (1999) indicated that the frequency of warm-wet (or cold-dry) predominated a
little over that of warm-dry (or cold-wet) in the far-west according to ice core data. Fig.6 also shows
some positive correlation in the western part of the country. Therefore, the characteristics of climatic
change in the north China may vary from west to east. However, changes of precipitation seem
considerably complex, and vary with time scale examined. Consequently, no unique link between
precipitation change and temperature was found. Long series of about 2000 years of Shi et al. (1999)
came to the same conclusion. The wet condition observed during the Megathermal may be related to
the change of forcing factors of much larger time scale, which are differ from that of annual to decadal
time scale. However, precipitation changes during the Megathermal need to be examined in detail with
much more evidences.
Conclusions
1. 1998 was the warmest year since 1880 in China.
2. The 1990s (1990-1998) were the second warmest decade since 1880’s. The mean temperature
anomaly (0.58℃) of it was a little colder than that of 1940’s (0.62℃).
3. The 20th century in China was the warmest during the last millennium or more (9th to 20th century).
Century mean temperature anomaly was 0.40℃ in reference of the average of 1200 years.
4.However, mean temperature of the last millennium was 0.3℃ lower than the present (1880-1979)
and was much colder than that between 3.0 and 8.0ka BP in which temperature was 1.5-2.0℃
higher than the present.
5. Evidence shows precipitation, especially in summer, mostly was below normal in north China when
climate was warm in MWP, or in 1920-1949. However, precipitation may be greater than at present
during the Megathermal.
Acknowledgement: This research is supported by National Key Program for Developing Basic Sciences
(G199804900-part 1) and the National Natural Science Foundation of China (49635190).
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Table 1 Data sources used in construction of regional temperature series for 1880-1998
1880-1910
1911-1950
1951-1998
Weighting
1 Northeast
Os
G
O
0.131
2 North
Os
G
O
0.084
3 East
Os
G
O
0.043
4 South
Os
G
O
0.059
5 Taiwan
Os, H
O
O
0.011
6 Middle
H
G
O
0.072
7 Southwest
H
G
O
0.071
8 Northwest
ID
G
O
0.198
9 Xinjiang
IG
IG
O
0.149
10 Tibet
Tr
Tr,Os
O
0.182
O observational data of five key stations
G temperature grade of five key stations
Os observational data of a single station
H Historical documents
ID Dunde ice core 18O
IG Guliya ice core 18O
Tr tree- ring width
Table 2 Definition of the Severity Index for North China
Index
spring
summer
Frost in April,
Heavy flood,
-0.5
heavy snowing,
frost
prolonged rain
Frost in May,
Frost in August,
frost damaging
rain lasted for a
grain,
couple of ten days,
-1.0
Snowing in
light snowing,
May,
glazing,
glazing
-2.0
Severe frost,
bitter cold,
damaging grain,
frozen lake,
river or well,
snow cover
maintained
Frost in June or
July,
bitter cold as in
winter,
snowing,
freezing on the
ground
autumn
Prolonged rain in
September,
snowing
Frost damaging
grain,
heavy snowing,
freezing on the
ground
Snowing lasted for
several ten days,
bitter clod,
travel on the frozen
lake or river
winter
Heavy
snowing,
heavy gazing
Heavy
snowing,
snowing lasted for
several ten days,
bitter cold,
damaging trees to
death,
frozen well
Heavy
snowing
without melting
till spring,
frozen lake,
river or sea
Table 3. Three cold spells in the Little Ice Age and the temperature anomalies (with respected to
1880-1970s. In C)
Cold Spells
Warm period
Time
I1
I2
II1
II2
III1
III2
1450s
1490s
1560s
1620s
1790s
1830s
1920
/
/
/
/
/
/
/
1470s
1510s
1600s
1690s
1810s
1890s
1940s
Northern China
-0.29
-0.06
-0.47
-0.63
-0.45
-0.32
0.49
Eastern China
-0.31
-0.61
-0.47
-0.57
-0.41
-0.58
0.43
Whole China
-0.47
-0.40
-0.30
0.43
8
Table 4. Sources of the documentary evidence (AD 800-AD 1399)
No. Year
Dynasty
Disasters
Items
1 A.D.800-1399
Tang-Ming
Cold winter
42
Warm winter
40
Cold summer
34
Warm summer
36
2 A.D.800-941
Mid.Tang-Wudai Cold events
12
A.D.960-1100
Beisong
Temp.anomalies
15
A.D.1288-1340
Yuan
Heavy snow
13
A.D.962-1228
Song
Cold & warm events 67
3 A.D.962-1127
Beisong
Cold events
19
A.D.1018-1371
Song-Ming
Serevere cold events 7
A.D.821-1399
Tang-Ming
Cold winter
36
4 A.D.627-904
Tang
Freeze
33
A.D.814-947
Nantang, Beiqi Freeze, hot summer 5
A.D.821-903
Tang
Sea ice
2
A.D.962-1237
Song
Freeze
36
A.D.988-1113
Liao
Freeze
7
A.D.1197-1232
Jin
Freeze
10
A.D.1284-1368
Yuan
Freeze
30
5 A.D.628-902
Tang
Frost,snow
10
A.D.647-904
Tang
Serevere cold events 17
A.D.821-903
Tang
Sea ice
3
6 A.D.928-1113
Liao
Freeze
15
Table 5. Pollen data sites
Region
Site
1 East. North
Gushantun
2 North
East Hebei
3 East
Jianhu Lake
4 South
Pear River Delta
5 Taiwan
Riyuetan Lake
6 Central
Dongting Lake
7 Sou. East
Guizhou
8 Nor. West
Qinghai Lake
9 Xinjiang
Aibi Lake
10 Tibet
Bangong Lake
Latitude (N)
42
40
34
23
24
29
28
37
45
34
References
Wang,1990b,17-18p
Wang,1990b,17-18p
Wang 1990b,18-19p
Wang 1990b,18-19p
Shi and Zhang,1996,292p
Shi and Zhang,1996,297p
Shi and Zhang,1996,299p
Shi and Zhang,1996,439p
Wen and Wen,1996,146p
Wen and Wen,1996,120p
Wen and Wen,1996,156-157p
Gao,1997,73-74p
Gao,1997,78p
Gao,1997,92p
Gao,1997,172-173p
Gao,1997,175-176
Gao,1997,177p
Gao,1997,182-183p
Man,1998,26p
Man,1998,26p
Man,1998,26p
Deng,1998,48-49p
Longitude (E)
126
118
120
114
121
113
109
100
83
80
Reference
Shi,1992,p33-39
Shi,1992,p1-38
Shi,1992,p80-93
Shi,1992,p121
Shi,1992,p91
Shi,1992,p120
Shi,1992,p123
Shi,1992,p48-65
Shi,1992,p168-174
Shi,1992,p197-205
Table 6 Characters of droughts and floods by types
Type
Summer rainfall pattern
1a
Floods over east China (to the east of 105E), but mainly along the
middle and lower reaches of the Changjiang River
1b
Floods along the middle and lower reaches of the Changjiang River,
droughts to the north and the south of it
2
Floods in the south of the Changjiang River and droughts in the north
of it
3
Droughts along the middle and lower reaches of the Changjiang River,
floods to the north and the south of it
4
Droughts in the south of the Changjiang River and floods in the north
of it
5
Droughts over almost whole area to the east of 105E
9
Table 7 Frequency of summer rainfall types during 1920-1949 and 1880-1909
Years
1a
1b
2
3
4
5
total
1920-1949
0
3
6
4
30
9
8
1880-1909
3
4
6
3
30
6
8
normal
4.9 4.4
6.7 5.7 5.1
3.2
30
Table 8 Percentage frequency of summer rainfall types during the Medieval Warm Period and the Little
Ice Age
Period
1a
1b
2
3
4
5
Total
MWP(AD 950-1099)
16.0
16.4
26.4
16.0
14.8
10.4
250a(100%)
(AD1200-1299)
LIA(1620-1699)
13.9
12.2
20.5
22.8
20.6
10.0
180a(100%)
(1790-1819)
(1830-1899)
Normal
16.5
14.6
22.5
18.9
16.9
10.6
1050a(100%)
Figure captions
Fig. 1. Ten climatic regions and stations over China. Regional mean temperatures are obtained by
averaging 5 stations' observations (those stations are shown as " " and "") for each region in the
period 1951-1998. " " denote that temperature grades data are used to calculate the regional
temperature for the period 1911-1950. Regional mean temperatures are generally calculated using
single stations' data for 1880-1910, these stations are shown as "". Due to the lack of data for
Region 8 and 9, the ice core data are incorporated, and for Region 10 the tree-ring data are also
used in the earlier period. To interpolate the gaps in records some other stations labeled "" also
take part in. " " indicate the ice core sites.
Fig. 2. Annual mean temperature anomalies of China. All ten regions are multiplied by area
weights and then added together to form a single series for whole China. Reference period is
1961-1990.
Fig. 3. Temperatures in China since 1380. (a) Northern China, (b) Eastern China, (c) Whole China.
The means of the whole series are shown as the dotted lines. In C.
Fig. 4. Temperature of China since A.D.800. (a) The eastern China, (b) the western China, (c)
whole China. The means of the whole series are shown as the dotted lines. In C.
Fig. 5. Temperature of China in Holocene for ten regions' mean.
Fig. 6. Correlation between the annual temperature and precipitation. Areas with confidence limit
of 0.05 are shaded. Data for 160 stations are used for the period 1951-98.
Fig.7. Anomalies of the mean annual precipitation for (a) 1920-40, (b) 1880-1909 and (c) the
difference between them. With respect to 1961-90.
10
50N
1
Harbin *
9
2
*Jiuquan
40N
Hetian *
Dunde
8
Beijing
*
Guliya
6
10
30N
Lasa
Wuhan *
*
3
* Shanghai
7
*
Kunming
*
4
* Taipei
5
Guangzhou
20N
70E
80E
90E
100E
110E
120E
130E
Fig. 1. Ten climatic regions and stations over China. Regional mean temperatures are obtained by
averaging 5 stations' observations (those stations are shown as " " and "") for each region in the
period 1951-1998. " " denotes that temperature grades data are used to calculate the regional
temperature for the period 1911-1950. Regional mean temperatures are generally calculated using
single stations' data for 1880-1910, these stations are shown as "". Due to the lack of data for
Region 8 and 9, the ice core data are incorporated, and for Region 10 the tree-ring data are also
used in the earlier period. To interpolate the gaps in records some other stations labeled "" also
take part in. " " indicate the ice core sites. See Table 1 and text for details.
1.0
0.5
0.0
-0.5
-1.0
1880
1900
1920
1940
1960
1980
2000
Fig. 2. Annual mean temperature anomalies of China. All ten regions are multiplied by area
weights and then added together to form a single series for whole China. Reference period is
1961-1990.
11
0.5
0.0
(a)
-0.5
0.5
(b)
0.0
-0.5
0.5
(c)
0.0
-0.5
1400
1450
1500
1550
1600
1650
1700
1750
1800
1850
1900
1950
2000
Fig. 3. Temperatures in China since 1380. (a) Northern China, (b) Eastern China, (c) Whole China.
The means of the whole series are shown as the dotted lines. In C.
0.2
0.0
(a)
-0.2
-0.4
0.2
-0.6
(b)
0.0
-0.2
-0.4
-0.6
0.2
0.0
(c)
-0.2
-0.4
-0.6
800
900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
Fig. 4. Temperature of China since A.D.800. (a) The eastern China, (b) the western China, (c)
whole China. The means of the whole series are shown as the dotted lines. In C.
12
Temp./ Cel. Degree
2
1
0
-1
-2
10
9
8
7
6
5
4
3
2
1
0 KaBP
Fig. 5. Temperature of China in Holocene for ten regions' mean.
50N
40N
30N
20N
80E
100E
120E
Fig. 6. Correlation between the annual temperature and precipitation. Areas with confidence limit
of 0.05 are shaded. Data for 160 stations are used for the period 1951-98.
13
b) 1880-1909
50N
50N
40N
40N
30N
30N
20N
20N
100E
50N
a) 1920-1940
110E
120E
130E
110E
120E
130E
100E
110E
120E
130E
c) a-b
40N
30N
20N
100E
Fig.7. Anomalies of the mean annual precipitation for (a) 1920-40, (b) 1880-1909 and (c) the
difference between them. With respect to 1961-90.
14