Effects of Urbanization on Regional Extreme-Temperature Changes in China, 1960–2016

Urbanization in China has been expanding dramatically since 1978, significantly affecting the extreme temperature changes in cities, which is a vital indicator of urban climate change. To assess urban-related effect on regional extreme-temperature changes in China, this study employed high-resolution land use data to divide meteorological stations into rural stations, suburban stations, and urban stations, and evaluated the annual and seasonal changes in extreme minimum temperature (TNN), mean temperature (Tavg) and extreme maximum temperature (TXX) at each meteorological station. The result revealed that extreme temperature indices (TNN, TXX) and Tavg increased significantly from 1960 to 2016 with varied degrees in different seasons and different regions. Extreme temperature indices in high latitudes increased more rapidly than in low latitudes; while the trends in summer are slower than in other seasons. Urbanization effects on the trends of TNN, Tavg and TXX were all statistically significant, but urbanization effects on TNN and Tavg were more significant than TXX. The urbanization effects were more significant in low altitudes, especially in North, South, Northwest and Northeast China. In North, Northwest and Northeast China, the urban-related effects on temperature increase were mainly observed in spring and winter, but in South China, the urban-related effects were more evident in summer. This study is valuable for sustainable urban planning in China.

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Effects of Urbanization on Regional Extreme-Temperature Change in China，1960-2016

10.5194/egusphere-egu2020-3514 ◽

2020 ◽

Author(s):

Junliang Qiu ◽

Xiankun Yang ◽

Bowen Cao ◽

Zhilong Chen ◽

Yuxuan Li

Keyword(s):

Temperature Change ◽

Statistical Significance ◽

Extreme Temperature ◽

Maximum Temperature ◽

Seasonal Temperature ◽

Temperature Changes ◽

Low Latitudes ◽

Extreme Minimum Temperature ◽

Land Cover Map ◽

Regional Temperature

<p>Fast urbanization is one of the aggrandizement factors to global warming, but the effects of urbanization on extreme temperature change is still not quantitatively assessed. Based on high-resolution land cover map, this study classified 613 meteorological stations in China into three classes, namely, urban station, suburban station and rural station to simulate the trends of extreme minimum temperature (TNN), mean temperature (Tavg) and extreme maximum temperature (TXX) of each meteorological station. The roles of urbanization in temperature change in the period 1960-2016 were then assessed. The results indicated that annual temperature increased significantly, but seasonal temperature increased with varied degrees. Temperature in high latitudes increased faster than that in low latitudes. Temperature in summer increased slower than that in other seasons. The effects of urbanization on TNN, Tavg and TXX were all statistically significant, but the effects on TNN and Tavg were more noticeable than TXX. The aggrandizement effects of urbanization presented by low-altitude meteorological stations are significant in South China and East China for all temperature indices, despite no statistical significance presented by high-altitude meteorological stations in Southwest China. This paper can provide a reference for understanding the regional temperature changes and the effects of urbanization on its changes in China.</p>

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Change in mean and extreme temperature at Yingkou station in Northeast China from 1904 to 2017

Climatic Change ◽

10.1007/s10584-021-02981-w ◽

2021 ◽

Vol 164 (3-4) ◽

Author(s):

Xiaoying Xue ◽

Guoyu Ren ◽

Xiubao Sun ◽

Panfeng Zhang ◽

Yuyu Ren ◽

...

Keyword(s):

Northeast China ◽

Extreme Temperature ◽

Maximum Temperature ◽

Data Set ◽

The Past ◽

Significant Downward Trend ◽

Cold Events ◽

Temperature Indices ◽

Increasing Trends ◽

Change In Mean

AbstractThe understanding of centennial trends of extreme temperature has been impeded due to the lack of early-year observations. In this paper, we collect and digitize the daily temperature data set of Northeast China Yingkou meteorological station since 1904. After quality control and homogenization, we analyze the changes of mean and extreme temperature in the past 114 years. The results show that mean temperature (Tmean), maximum temperature (Tmax), and minimum temperature (Tmin) all have increasing trends during 1904–2017. The increase of Tmin is the most obvious with the rate of 0.34 °C/decade. The most significant warming occurs in spring and winter with the rate of Tmean reaching 0.32 °C/decade and 0.31 °C/decade, respectively. Most of the extreme temperature indices as defined using absolute and relative thresholds of Tmax and Tmin also show significant changes, with cold events witnessing a more significant downward trend. The change is similar to that reported for global land and China for the past six decades. It is also found that the extreme highest temperature (1958) and lowest temperature (1920) records all occurred in the first half of the whole period, and the change of extreme temperature indices before 1950 is different from that of the recent decades, in particular for diurnal temperature range (DTR), which shows an opposite trend in the two time periods.

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Trends in Thailand’s Extreme Temperature Indices during 1955-2018 and Their Relationship with Global Mean Temperature Change

Applied Environmental Research ◽

10.35762/aer.2020.42.2.8 ◽

2020 ◽

pp. 94-107

Author(s):

Atsamon Limsakul

Keyword(s):

Global Warming ◽

Extreme Temperature ◽

Local Scale ◽

Maximum Temperature ◽

Temperature Extremes ◽

Global Mean Temperature ◽

Temperature Distributions ◽

Mean Temperature ◽

Temperature Indices ◽

Global Mean

Trends in Thailand’s extreme temperature indices and their relationship with global mean temperature (GMT) change are analyzed, based on longer quality controlled temperature data during 1955–2018. Widespread significant trends of extreme temperature indices with a clear warming evident in all indices are observed, consistent with the earlier results and general global warming. Changes associated with the upper tails of the minimum and maximum temperature distributions are the dominant feature of Thailand’s extreme temperature indices accounting for more than 65% of the total variance. Analysis of the probability distribution functions (PDFs) of combined extreme temperature indices further shows significant shifts in their distributions toward warmer conditions in the recent decades. The results suggest that daytime and nighttime temperatures in Thailand have become more extreme and that the changes are related to shifts in multiple aspects of the daily temperature distributions. With long-term temperature records, this study provides more confident and robust evidence of trends in Thailand’s temperature extremes occurred since the second half of 20th century. Another noteworthy finding is that most of Thailand’s extreme temperature indices show a distinct linear relationship with GMT, indicating that local-scale changes in temperatures and its extreme at local scale are related almost linearly to GMT change. The extrapolated values of the indices with strong linearity with GMT show substantial distinction with nearly 50% increase between 2 global warming levels set by Paris Agreement, highlighting that half a degree increase in GMT will lead to greatly increase in Thailand’s temperature extremes.

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Expected changes in future temperature extremes and their elevation dependency over the Yellow River source region

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-9-13609-2012 ◽

2012 ◽

Vol 9 (12) ◽

pp. 13609-13634

Author(s):

Y. Hu ◽

S. Maskey ◽

S. Uhlenbrook

Keyword(s):

Interannual Variability ◽

Yellow River ◽

Source Region ◽

Extreme Temperature ◽

Maximum Temperature ◽

The Yellow River ◽

Hot Days ◽

Yellow River Source ◽

Temperature Indices ◽

Ipcc Sres

Abstract. Using the Statistical DownScaling Model (SDSM) and the outputs from two global climate models we investigate possible changes in mean and extreme temperature indices and their elevation dependency over the Yellow River source region for the period 2081–2100 under the IPCC SRES A2, A1B and B1 emission scenarios. Changes in interannual variability of mean and extreme temperature indices are also analyzed. The validation results show that SDSM performs better in reproducing the maximum temperature-related indices than the minimum temperature-related indices. The projections show that by the end of the 21st century all parts of the study region may experience increases in both mean and extreme temperature in all seasons, along with an increase in the frequency of hot days and warm nights and with a decrease in frost days. Interannual variability increases in all seasons for the frequency of hot days and warm nights and in spring for frost days while it decreases for frost days in summer. Autumn demonstrates pronounced elevation-dependent changes in which six out of eight indices show significant increasing changes with elevation.

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Historical Variability And Future Changes In Seasonal Extreme Temperature Over Iran

10.21203/rs.3.rs-739242/v1 ◽

2021 ◽

Author(s):

Azar Zarrin ◽

Abbasali Dadashi-Roudbari ◽

Samira Hassani

Keyword(s):

Climate Change ◽

General Circulation ◽

Extreme Temperature ◽

Maximum Temperature ◽

Cmip5 Models ◽

Daily Minimum Temperature ◽

Daily Maximum Temperature ◽

Important Indicator ◽

Taylor Diagram ◽

Temperature Indices

Abstract The extreme temperature indices (ETI) are an important indicator of climate change, the detection of their changes over the next years can play an important role in the Climate Action Plan (CAP). In this study, four temperature indices (Mean of daily minimum temperature (TN), Mean of daily maximum temperature (TX), Cold-spell duration index (CSDI), and Warm-spell duration index (WSDI)) were defined by ETCCDI and two new indices of the Maximum number of consecutive frost days (CFD) and the Maximum number of consecutive summer days (CSU) were calculated to examine ETIs in Iran under climate change conditions. We used minimum and maximum daily temperature of five General circulation models (GCMs) including HadGEM2-ES, IPSL-CM5A-LR, GFDL-ESM2M, MIROC-ESM-CHEM, and NorESM1-M from the set of CMIP5 Bias-Correction models. We investigated Two Representative Concentration Pathway (RCP) scenarios of RCP4.5 and RCP8.5 – during the historical (1965-2005) and future (2021-2060 and 2061-2100) periods. The performance of each model was evaluated using the Taylor diagram on a seasonal scale. Among models, GFDL-ESM2M and HadGEM2-ES models showed the highest, and NorESM1-M and IPSL-CM5A-LR models showed the lowest performance in Iran. Then an ensemble model was generated using Independence Weighted Mean (IWM) method. The results of multi-model ensembles (MME) showed a higher performance compared to individual CMIP5 models in all seasons. Also, the uncertainty value was significantly reduced, and the correlation value of the MME model reached 0.95 in all seasons. Additionally, it is found that WSDI and CSU indices showed positive anomalies in future periods and CSDI and CFD showed negative anomalies throughout Iran. Also, at the end of the 21st century, no cold spells are projected in almost every part of Iran. The CSU index showed that Iran's summer days are increasing sharply, according to the results of the RCP8.5 scenario in spring (MAM) and autumn (SON), the CSU will increase by 18.79 and 20.51 days, respectively at the end of the 21st century. It is projected that in the future, the spring and autumn seasons will be shorter and, summers, will be much longer than before.

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Analysis of some extreme temperature indices over Iraq

MAUSAM ◽

10.54302/mausam.v71i3.40 ◽

2021 ◽

Vol 71 (3) ◽

pp. 423-430

Author(s):

AL-TIMIMI YASEEN K ◽

AL-LAMI ALAA M ◽

AL-SHAMARTI HASANAIN K A ◽

AL-MAAMORY SAMIR K.

Keyword(s):

Extreme Temperature ◽

Regression Method ◽

Maximum Temperature ◽

Data Display ◽

Annual Average ◽

Maximum Value ◽

Increasing Trend ◽

Temperature Indices ◽

Maximum Temperatures ◽

Negative Impacts

Climate change has negative impacts on different sectors. Generally, data display significant changes in the properties of extreme events. Daily minimum and maximum temperatures data for 36 meteorological stations of Iraq (1981-2017) were analysed to detect the significant trend and the magnitude trend extreme temperature indices over the 36-year period. RClimDex was used to compute indices and simple regression method was used for trend analysis. The results show that all stations displayed a significant increase in the annual average of maximum value of maximum temperature TXx and the annual average of maximum value of minimum temperature TNx. For the annual diurnal temperature range, about 81.6% of stations have a decreasing trend, while 18.4% have an increasing trend. The TXn index shows 78.9 has a decreasing trend for all stations except 5.3% have no change and 15.8% have an increasing trend. In contrast, the represent of TNn index demonstrate a decreasing trend for 63.2% of stations and 31.6% have an increasing trend fall all stations. Analysis of temperature extremes revealed a significant increase in most stations, which also shows that the country has seen a trend of warming.

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Climate extremes in multi-model simulations of stratospheric aerosol and marine cloud brightening climate engineering

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-9593-2015 ◽

2015 ◽

Vol 15 (16) ◽

pp. 9593-9610 ◽

Cited By ~ 19

Author(s):

V. N. Aswathy ◽

O. Boucher ◽

M. Quaas ◽

U. Niemeier ◽

H. Muri ◽

...

Keyword(s):

Extreme Precipitation ◽

Extreme Temperature ◽

The Arctic ◽

Large Temperature ◽

Frequency Of Occurrence ◽

Climate Engineering ◽

Temperature Changes ◽

Dry Spell ◽

Low Latitudes ◽

The Mean

Abstract. Simulations from a multi-model ensemble for the RCP4.5 climate change scenario for the 21st century, and for two solar radiation management (SRM) schemes (stratospheric sulfate injection (G3), SULF and marine cloud brightening by sea salt emission SALT) have been analysed in terms of changes in the mean and extremes of surface air temperature and precipitation. The climate engineering and termination periods are investigated. During the climate engineering period, both schemes, as intended, offset temperature increases by about 60 % globally, but are more effective in the low latitudes and exhibit some residual warming in the Arctic (especially in the case of SALT which is only applied in the low latitudes). In both climate engineering scenarios, extreme temperature changes are similar to the mean temperature changes over much of the globe. The exceptions are the mid- and high latitudes in the Northern Hemisphere, where high temperatures (90th percentile of the distribution) of the climate engineering period compared to RCP4.5 control period rise less than the mean, and cold temperatures (10th percentile), much more than the mean. This aspect of the SRM schemes is also reflected in simulated reduction in the frost day frequency of occurrence for both schemes. However, summer day frequency of occurrence increases less in the SALT experiment than the SULF experiment, especially over the tropics. Precipitation extremes in the two SRM scenarios act differently – the SULF experiment more effectively mitigates extreme precipitation increases over land compared to the SALT experiment. A reduction in dry spell occurrence over land is observed in the SALT experiment. The SULF experiment has a slight increase in the length of dry spells. A strong termination effect is found for the two climate engineering schemes, with large temperature increases especially in the Arctic. Globally, SULF is more effective in reducing extreme temperature increases over land than SALT. Extreme precipitation increases over land is also more reduced in SULF than the SALT experiment. However, globally SALT decreases the frequency of dry spell length and reduces the occurrence of hot days compared to SULF.

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Urbanization Effect on Trends of Extreme Temperature Indices of National Stations over Mainland China, 1961–2008

Journal of Climate ◽

10.1175/jcli-d-13-00393.1 ◽

2014 ◽

Vol 27 (6) ◽

pp. 2340-2360 ◽

Cited By ~ 117

Author(s):

Guoyu Ren ◽

Yaqing Zhou

Keyword(s):

Mainland China ◽

Extreme Temperature ◽

Maximum Temperature ◽

Daily Minimum Temperature ◽

Urbanization Effect ◽

Detection And Attribution ◽

Time Period ◽

Term Change ◽

Temperature Indices

Abstract Understanding the long-term change of extreme temperature events is important to the detection and attribution of climate change. It is unclear, however, how much effect urbanization has had on trends of the extreme temperature indices series constructed based on the commonly used datasets on a subcontinental scale. Applying a homogenized daily temperature dataset of the national reference climate stations and basic meteorological stations, and a rural station network previously developed, urbanization effects on trends of extreme temperature indices in mainland China for the time period 1961–2008 are evaluated. It is found that 1) the country-averaged annual- and seasonal-mean extreme temperature indices series generally experience statistically significant trends; 2) annual-mean urbanization effects in the country as a whole are statistically significant for daily minimum temperature (Tmin), maximum temperature (Tmax), and mean temperature of Tmin and Tmax (Tavg), reaching 0.070°, 0.023°, and 0.047°C (10 yr)−1, respectively, with the largest values for annual-mean Tmin occurring in north China; 3) annual- and seasonal-mean urbanization effects for the declining diurnal temperature range (DTR) are highly significant, and the largest seasonal-mean DTR decline because of urbanization occurs in winter and spring; 4) annual-mean urbanization effects for the lowest Tmin, summer days, tropical nights, and frost days series are significant, but an insignificant urbanization effect is detected for icing days series; 5) urbanization has led to a highly significant decline of annual cold nights at a rate of −1.485 days (10 yr)−1 and a highly significant increase of annual warm nights at a rate of 2.264 days (10 yr)−1. Although urbanization effects are also significant for cold days and warm days, they are relatively smaller, and 6) the smallest absolute values of annual-mean urbanization effects for most of the indices series are found to dominantly appear during 1966–76, a well-known deurbanization period resulting from the Cultural Revolution.

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Temporal variability of extreme temperature indices in Utah during the past few decades

Revista Brasileira de Meteorologia ◽

10.1590/s0102-77862013000400002 ◽

2013 ◽

Vol 28 (4) ◽

pp. 364-372 ◽

Cited By ~ 1

Author(s):

Carlos Antonio Costa dos Santos ◽

José Ivaldo Barbosa de Brito ◽

Elder Guedes dos Santos ◽

Tantravahi Venkata Ramana Rao ◽

Vicente de Paulo Rodrigues da Silva

Keyword(s):

Temporal Variability ◽

Extreme Temperature ◽

Quality Data ◽

Maximum Temperature ◽

Data Set ◽

High Quality Data ◽

The Past ◽

Air Temperatures ◽

Temperature Indices ◽

Minimum Air Temperature

The main objective of this study was to analyze the trends in five annual extreme indices of temperature for Utah, USA. The analyses were conducted for 28 meteorological stations, during the period from 1970 to 2006, characterized by high quality data set. The analyses of extreme temperature indices have identified an increase in the maximum and minimum air temperatures in Utah. Predominantly, the minimum air temperature is increasing in the studied region. Most of Utah has shown a decrease in the diurnal temperature range, which indicates that the minimum temperature is increasing faster than the maximum temperature.

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Climate Change Projections of Extreme Temperatures for the Iberian Peninsula

Atmosphere ◽

10.3390/atmos10050229 ◽

2019 ◽

Vol 10 (5) ◽

pp. 229 ◽

Cited By ~ 12

Author(s):

Carolina Viceto ◽

Susana Cardoso Pereira ◽

Alfredo Rocha

Keyword(s):

Iberian Peninsula ◽

Heat Wave ◽

Heat Waves ◽

Extreme Temperature ◽

Extreme Heat ◽

Recovery Factor ◽

Maximum Temperature ◽

Weather Research And Forecasting ◽

Temperature Changes ◽

Temperature Thresholds

The comprehensive characterization of heat waves and extreme hot days is fundamental for policymakers due to its vast implications for human health. This study evaluates extreme temperature changes over the Iberian Peninsula for the present climate and future projections, considering extreme temperature indices, cold/heat waves, and a recovery factor, using the Weather Research and Forecasting model. The projected temperatures show an increase of over 6 °C. An increase in the number of summer days and tropical nights and a decrease in frost days is expected. The number of heat waves and their duration and intensity are expected to increase. The number of heat wave days are expected to increase, with much of the average summer season being under heat wave conditions. The recovery factor is expected to decrease. Cold spells are projected to decrease in terms of number, intensity, duration, and number of spell days, whereas the recovery factor is expected to increase. Heat wave analysis was combined with maximum temperature thresholds to isolate extreme heat waves. The results show an increase in extreme heat wave days, with regions experiencing over 10 heat wave days with maximum temperature surpassing 45 °C for the long-term future.

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