Electronic Supplementary Material
Assessment of urban effect on observed warming trends during 1955-2012 over China:
a case of 45 cities
Climatic Change
Kai Jin a, Fei Wang a, b, c *, Deliang Chen d, Qiao Jiao b, Lei Xia c, e, LuukFleskensf, g, Xingmin Mu a, b, c
aInstitute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China
bCollege of Natural Resources and Environment, Northwest A&F University,Yangling 712100, Shaanxi, China
cInstitute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of water Resources, Yangling 712100, Shaanxi, China
d Department of Earth Sciences, University of Gothenburg, Box 460, 405 30 Gothenburg, Sweden
e University of Chinese Academy of Sciences, Beijing 100049, China
f Soil Physics and Land Management Group, Wageningen University, P.O. Box 47, 6700AA, Wageningen, The Netherlands
g Sustainability Research Institute, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
E-mail: Mr. Kai Jin () and corresponding author, Dr. Fei Wang ()
Contents
SI-1 Meteorological stations and corresponding cities
SI-2 Trends of annual mean temperature of each meteorological stations in 1955-2012
SI-3 Urban impact indicators (Uii) in China
SI-4 Urban warming and their contribution to total warming for each station
Abbreviations and nomenclaturesAu / Urban area: Built-up land area, in km2
Dir / Direction: Direction of meteorological station relative to city center, 16 azimuth
Dis / Distance: the distance from meteorological station to city center, in km
NDVI / Normalized Difference Vegetation Index, unitless
OLS / Operational Linescan System
PC / Principal component
PCA / Principal Component Analysis
Pop / Population: non-agricultural population, in million
R / Radius: the radius of city shape simplified as circle, in km
Rd / Distance coefficient: the ratio of Dis and R, unitless
Tmax / Annual mean daily maximum temperature, in °C
Tmean / Annual mean daily temperature, in °C
Tmin / Annual mean daily minimum temperature, in °C
UHI / Urban Heat Island
Uii / Urban impact indicator: the degree of the urbanization impact on the recorded surface temperature, in %
ESM / Electronic Supplemental Material
SI-1 Meteorological stations and corresponding cities
The characters of the 45 meteorological stations and corresponding cities are listed in Table S1.
We generalizes the urban area with NDVI to determine the city centerstaking account of the fact that vegetation coverage in the northwestern and northern parts of China is low, yet in small cities (Popless than 0.50 Million) it is high. Wang et al. (2006) showed that the mean NDVI of Beijing urban region varied from 0.27 to 0.39 during the period 1984 to 2004. Therefore, the following threshold values of NDVI for city areas were determined: NDVI ranging from 0.2 to 0.3 for the six cities in the northwest, for the 6 small cities in other regions ranging from 0.2 to 0.5, and for the other 33 cities ranging from 0.2 to 0.4.
Table S1Meteorological stations and corresponding cities
Name (abbr.) / Pop(million) / Au
(km2) / Dis
(km) / R
(km) / Rd / Na / NDVI / Dir
(16 azimuth) / Latitude
(°N) b / Longitude
(°E) b
Baoding (BD) / 0.93 / 100 / 2.8 / 5.6 / 0.5 / 1 / 0.2-0.4 / E / 38.85 / 115.52
Baotou (BT) / 1.15 / 178 / 3.1 / 7.5 / 0.4 / 1 / 0.2-0.3 / E / 40.67 / 109.85
Beijing (BJ) / 8.79 / 1226 / 17.4 / 19.8 / 0.9 / 1 / 0.2-0.4 / SE / 39.80 / 116.47
Changchun (CC) / 2.51 / 267 / 11.0 / 9.2 / 1.2 / 2 / 0.2-0.4 / W / 43.90 / 125.22
Changde (CD) / 0.50 / 65 / 2.9 / 4.5 / 0.6 / 1 / 0.2-0.5 / NW / 29.05 / 111.68
Chifeng (CF) / 0.52 / 72 / 0.9 / 4.8 / 0.2 / 1 / 0.2-0.4 / W / 42.27 / 118.93
Dalian(DL) / 2.48 / 258 / 19.9 / 9.1 / 2.2 / 2 / 0.2-0.4 / E / 38.90 / 121.63
Datong (DT) / 1.15 / 91 / 4.4 / 5.4 / 0.8 / 1 / 0.2-0.3 / E / 40.10 / 113.33
Guangzhou (GZ) / 4.91 / 780 / 11.7 / 15.8 / 0.7 / 1 / 0.2-0.4 / NE / 23.17 / 113.33
Guiyang (GY) / 1.51 / 132 / 2.2 / 6.5 / 0.3 / 1 / 0.2-0.4 / E / 26.58 / 106.73
Haikou (HK) / 0.90 / 91 / 10.1 / 5.4 / 1.9 / 2 / 0.2-0.4 / SW / 20.00 / 110.25
Hangzhou (HZ) / 2.56 / 327 / 8.6 / 10.2 / 0.8 / 1 / 0.2-0.4 / S / 30.23 / 120.17
Hanzhong (HZg) / 0.25 / 31 / 0.4 / 3.1 / 0.1 / 1 / 0.2-0.5 / S / 33.07 / 107.03
Harbin (HB) / 3.41 / 331 / 11.3 / 10.3 / 1.1 / 1 / 0.2-0.4 / E / 45.75 / 126.77
Hefei (HF) / 1.61 / 225 / 8.7 / 8.5 / 1.0 / 2 / 0.2-0.4 / SE / 31.78 / 117.30
Hohhot (HH) / 0.84 / 150 / 1.7 / 6.9 / 0.2 / 1 / 0.2-0.4 / E / 40.82 / 111.68
Huiyang (HY) / 1.18 / 94 / 1.4 / 5.5 / 0.3 / 1 / 0.2-0.4 / E / 23.08 / 114.42
Jinan (JN) / 2.77 / 305 / 10.4 / 9.9 / 1.1 / 1 / 0.2-0.4 / SE / 36.60 / 117.05
Kunming (KM) / 1.72 / 233 / 10.8 / 8.6 / 1.3 / 1 / 0.2-0.4 / SW / 25.00 / 102.65
Liuzhou (LZ) / 0.89 / 110 / 3.5 / 5.9 / 0.6 / 1 / 0.2-0.4 / N / 24.35 / 109.40
Mianyang (MY) / 0.61 / 80 / 4.1 / 5.0 / 0.8 / 1 / 0.2-0.4 / SW / 31.45 / 104.73
Nanchang (NC) / 1.74 / 109 / 6.6 / 5.9 / 1.1 / 2 / 0.2-0.4 / S / 28.60 / 115.92
Table S1 (continued)
Name (abbr.) / Pop(million) / Au
(km2) / Dis
(km) / R
(km) / Rd / N a / NDVI / Dir
(16 azimuth) / Latitude
(°N) b / Longitude
(°E) b
Nanjing (NJ) / 4.47 / 575 / 8.0 / 13.5 / 0.6 / 1 / 0.2-0.4 / SE / 32.00 / 118.80
Nanyang (NY) / 0.55 / 77 / 6.4 / 5.0 / 1.3 / 1 / 0.2-0.4 / NE / 33.03 / 112.58
Qinzhou (QZ) / 0.20 / 34 / 2.8 / 3.3 / 0.9 / 1 / 0.2-0.5 / SE / 21.95 / 108.62
Qiqihar (QH) / 1.11 / 135 / 9.6 / 6.6 / 1.5 / 1 / 0.2-0.4 / NW / 47.38 / 123.92
Rizhao (RZ) / 0.60 / 61 / 4.0 / 4.4 / 0.9 / 1 / 0.2-0.4 / NW / 35.43 / 119.53
Shantou (ST) / 4.88 / 170 / 8.7 / 7.4 / 1.2 / 3 / 0.2-0.4 / N / 23.40 / 116.68
Shenyang (SY) / 4.44 / 325 / 14.8 / 10.2 / 1.5 / 1 / 0.2-0.4 / SE / 41.73 / 123.52
Shijiazhuang (SJ) / 2.31 / 175 / 9.9 / 7.5 / 1.3 / 1 / 0.2-0.4 / W / 38.03 / 114.42
Tangshan (TS) / 1.63 / 209 / 6.4 / 8.2 / 0.8 / 1 / 0.2-0.4 / NW / 39.67 / 118.15
Urumchi (UM) / 1.58 / 236 / 3.9 / 8.7 / 0.4 / 1 / 0.2-0.3 / SE / 43.78 / 87.65
Weifang (WF) / 0.98 / 123 / 8.5 / 6.3 / 1.4 / 1 / 0.2-0.4 / NE / 36.75 / 119.18
Wuhan (WH) / 4.45 / 425 / 20.9 / 11.6 / 1.8 / 1 / 0.2-0.4 / W / 30.62 / 114.13
Wuwei (WW) / 0.21 / 25 / 3.2 / 2.8 / 1.1 / 1 / 0.2-0.3 / SE / 37.92 / 102.67
Xiamen (XM) / 1.09 / 127 / 10.0 / 6.4 / 1.6 / 3 / 0.2-0.4 / NW / 24.48 / 118.07
Xining (XN) / 0.91 / 64 / 13.8 / 4.5 / 3.1 / 1 / 0.2-0.4 / N / 36.72 / 101.75
Xinyang (XY) / 0.44 / 48 / 5.2 / 3.9 / 1.3 / 1 / 0.2-0.5 / W / 32.13 / 114.05
Yichang (YCg) / 0.70 / 71 / 2.4 / 4.8 / 0.5 / 1 / 0.2-0.4 / E / 30.70 / 111.30
Yichun (YCn) / 0.26 / 32 / 5.1 / 3.2 / 1.6 / 1 / 0.2-0.5 / NE / 27.80 / 114.38
Yinchuan (YC) / 0.71 / 106 / 8.0 / 5.8 / 1.4 / 2 / 0.2-0.3 / W / 38.48 / 106.22
Yueyang (YY) / 0.94 / 78 / 6.3 / 5.0 / 1.3 / 1 / 0.2-0.4 / NW / 29.38 / 113.08
Yulin (YL) / 0.16 / 74 / 5.2 / 4.9 / 1.1 / 1 / 0.2-0.3 / SE / 38.27 / 109.78
Yuxi (YX) / 0.14 / 21 / 2.9 / 2.6 / 1.1 / 1 / 0.2-0.4 / SE / 24.33 / 102.55
Zhengzhou (ZZ) / 1.93 / 282 / 6.4 / 9.5 / 0.7 / 1 / 0.2-0.4 / S / 34.72 / 113.65
Note:a is the number of city centers (N); bis the Latitude and Longitude of the meteorological stations.
Table S2Descriptive statistics of selected characteristics of 45 meteorological stations and cities
Au (km2) / Pop(million) / Dis (km) / R (km) / RdMean / 193.96 / 1.72 / 7.25 / 7.10 / 1.03
Median / 123.00 / 1.11 / 6.40 / 6.30 / 1.10
Standard deviation / 216.93 / 1.72 / 4.87 / 3.43 / 0.57
Minimum (City) / 21.00 (YX) / 0.14 (YX) / 0.40 (HZ) / 2.60 (YX) / 0.10 (HZ)
Maximum (City) / 1226.00 (BJ) / 8.79 (BJ) / 20.90 (WH) / 19.80 (BJ) / 3.10 (XN)
Coefficient of variation / 1.12 / 0.99 / 0.67 / 0.48 / 0.56
SI-2 Trends of annual mean temperature of each meteorological stations in 1955-2012
The trends of Tmean, Tmin and Tmax of the 45 stations were detected by linear regressions between temperature and year using observed temperature datain 1955-2012(Table 1 and Fig. S1).
Generally, the temperature increase in 1955-2012 over the China except for GY (decreasing). The warming trends become weaker from the north part to the south part of China. The change rate of Tmin is bigger than that of Tmean, and the change rate of Tmax is relatively low.
Fig. S1Trends of annual mean temperature of each meteorological stations in 1955-2012
(a, b, c depict annual mean daily temperature, annual mean daily minimum temperature and annual mean daily maximum temperature, respectively)
SI-3 Urban impact indicators (Uii) in China
The Urban impact indicators (Uii)of the 45 stations were calculated using the formulae shown in Fig. 2 (Fig. S2). The mean Uii of all stations is 11.2% (Table 1), but it varies greatly among the cities with a coefficient of variation of 0.81. The difference of Uii between stations is very large from 1.0% (minimum in YX) to 38.2% (maximum in BJ).
Fig. S2 Urban impact indicators (Uii) of the 45 meteorological stations in China
(According to the Uii of 45 meteorological stations included in this study, the impact of urbanization is divided into five levels: marginal impact (Uii < 5%), slight impact (5% ≤ Uii < 10%), medium impact (10% ≤ Uii < 15%), evident impact (15% ≤ Uii < 25%), and severe impact (Uii ≥ 25%))
SI-4Urban warming and their contribution to total warming for each station
The Urban warming here (Y, in °C per decade, Table S3) is the warming rate caused by urbanization (indicated as Uii, in %). The regression equations here are from Fig.4 (constants are set as 0), and as below:
YTmin = 0.48 * X (S1)
YTmean = 0.41 * X (S2)
The contribution of urbanization to the total warming(in %, Table S3) is theproportion of Urban warming (in °C per decade) in temperature change trend (in °C per decade) of each meteorological station (formulaS3) as below.
Contribution = Y/Trend * 100%(S3)
Table S3Magnitude of urban warming and their contribution to total warming for each station
Name (abbr.) / Urban warming(°C per decade) / Contribution
(%) / Name (abbr.) / Urban warming
(°C per decade) / Contribution
(%)
Tmin / Tmean / Tmin / Tmean / Tmin / Tmean / Tmin / Tmean
Baoding (BD) / 0.07 / 0.06 / 14.30 / 20.50 / Nanyang (NY) / 0.03 / 0.02 / 7.99 / 14.45
Baotou (BT) / 0.09 / 0.08 / 16.59 / 18.45 / Qinzhou (QZ) / 0.04 / 0.03 / 15.92 / 15.63
Beijing (BJ) / 0.18 / 0.16 / 34.61 / 39.17 / Qiqihar (QH) / 0.02 / 0.01 / 3.62 / 4.25
Changchun (CC) / 0.02 / 0.02 / 4.21 / 5.05 / Rizhao (RZ) / 0.03 / 0.03 / 13.47 / 10.18
Changde (CD) / 0.05 / 0.04 / 15.99 / 18.41 / Shantou (ST) / 0.05 / 0.04 / 17.84 / 15.24
Chifeng (CF) / 0.06 / 0.05 / 19.07 / 20.20 / Shenyang (SY) / 0.03 / 0.03 / 20.97 / 14.75
Dalian(DL) / 0.03 / 0.03 / 9.91 / 9.64 / Shijiazhuang (SJ) / 0.03 / 0.02 / 4.62 / 6.38
Datong (DT) / 0.06 / 0.05 / 21.44 / 18.31 / Tangshan (TS) / 0.09 / 0.08 / 28.70 / 29.05
Guangzhou (GZ) / 0.11 / 0.10 / 56.05 / 53.20 / Urumchi (UM) / 0.12 / 0.10 / 27.75 / 36.40
Guiyang (GY) / 0.06 / 0.05 / 100 / 100 / Weifang (WF) / 0.01 / 0.01 / 6.66 / 7.20
Haikou (HK) / 0.01 / 0.01 / 3.94 / 4.96 / Wuhan (WH) / 0.03 / 0.02 / 6.28 / 7.86
Hangzhou (HZ) / 0.14 / 0.12 / 41.69 / 37.84 / Wuwei (WW) / 0.03 / 0.02 / 7.49 / 6.96
Hanzhong (HZg) / 0.04 / 0.04 / 15.53 / 18.85 / Xiamen (XM) / 0.01 / 0.01 / 22.53 / 24.06
Harbin (HB) / 0.10 / 0.09 / 20.10 / 20.85 / Xining (XN) / 0.01 / 0.01 / 11.90 / 5.65
Hefei (HF) / 0.03 / 0.03 / 12.44 / 11.60 / Xinyang (XY) / 0.01 / 0.01 / 4.47 / 5.52
Hohhot (HH) / 0.09 / 0.08 / 14.02 / 15.64 / Yichang (YCg) / 0.04 / 0.04 / 23.46 / 32.80
Huiyang (HY) / 0.07 / 0.06 / 22.84 / 31.21 / Yichun (YCn) / 0.01 / 0.01 / 2.53 / 3.85
Jinan (JN) / 0.04 / 0.03 / 17.62 / 26.62 / Yinchuan (YC) / 0.02 / 0.02 / 5.34 / 5.26
Kunming (KM) / 0.03 / 0.02 / 5.46 / 6.85 / Yueyang (YY) / 0.02 / 0.02 / 6.79 / 8.85
Liuzhou (LZ) / 0.07 / 0.06 / 25.70 / 37.05 / Yulin (YL) / 0.05 / 0.04 / 12.62 / 14.01
Mianyang (MY) / 0.06 / 0.05 / 26.75 / 45.69 / Yuxi (YX) / 0.00 / 0.00 / 1.91 / 2.23
Nanchang (NC) / 0.03 / 0.02 / 11.71 / 13.34 / Zhengzhou (ZZ) / 0.11 / 0.10 / 30.95 / 37.62
Nanjing (NJ) / 0.17 / 0.15 / 57.96 / 59.41
Reference:
Wang W, Shen W, Liu X (2006) Research on the relation of the urbanization and urban heat island effect changes in Beijing based on remote sensing. Research of Environmental Sciences 19:44-48.doi:10.3321/j.issn:1001-6929.2006.02.014
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