Analysis on Temporal-spatial Distribution and Change Trend of the Temperature in Beibei District

[ Objective] The research aimed to analyze temporal-spatial distribution and change trend of the temperature in Beibei District. [ Method] Based on temperature observation data at 6 ground meteorological observatories of Beibei District from 1951 to 2010, EOF and linear trend method were used to analyze temporal-spatial distribution and change characteristics of the temperature in Beibei District in recent 60 years. [ Result] Tem- perature in Beibei District in recent 60 years overall presented rise trend, and average rise velocity was 0.045 ~C/10 a. Temperature rise in autumn was the most obvious, while summer temperature presented decline trend. Average temperature presented gradual rise trend from January to July and gradual decrease trend from August to December. Seen from spatial distribution, temperature in the whole district was higher in the west and lower in the middle. Abnormal spatial distribution of the average temperature in the whole district mainly had consistent higher （lower） type, south- north reverse type and east-west reverse type. [ Condusionl The research provided theoretical basis for effective disaster prevention and reduction in the zone.

Spatial and Temporal Analysis of Maximum and Minimum Temperature Trends in Northern Sudan during (1990-2019)

The study addresses an urgent and globally significant issue of climate change by focusing on the detailed spatial and temporal analysis of temperature trends in Northern Sudan. It fills a critical research gap by providing localized data over a substantial period (1990-2019), which could help in understanding the nuanced impacts of climate change in Sahel regions like Northern Sudan. In addition, the comprehensive coverage of both spatial and temporal dimensions, supported by a substantial dataset from five meteorological stations, provides a thorough understanding of the subject area. The utilization of robust statistical methods (Mann-Kendall test and Sen’s slope analysis) for analyzing temperature trends adds scientific rigor and credibility to the findings. Our results reveal a consistently increasing trend in maximum temperatures across most stations, particularly during the hot season (AMJ). However, the wet season (JAS) shows high maximum temperatures but no significant trend. Moreover, significant increasing trends in minimum temperatures were observed in all stations except Abu Hamed, where the trend, although increasing, did not reach statistical significance during the hot and cold seasons, and the coldest temperatures were observed during the cold season. These findings underscore the complex temperature dynamics in Northern Sudan and highlight the need for continued monitoring and adaptive measures in response to ongoing climate changes in the region.

Effects of temperature and precipitation on drought trends in Xinjiang, China

The characteristics of drought in Xinjiang Uygur Autonomous Region(Xinjiang),China have changed due to changes in the spatiotemporal patterns of temperature and precipitation,however,the effects of temperature and precipitation—the two most important factors influencing drought—have not yet been thoroughly explored in this region.In this study,we first calculated the standard precipitation evapotranspiration index(SPEI)in Xinjiang from 1980 to 2020 based on the monthly precipitation and monthly average temperature.Then the spatiotemporal characteristics of temperature,precipitation,and drought in Xinjiang from 1980 to 2020 were analyzed using the Theil-Sen median trend analysis method and Mann-Kendall test.A series of SPEI-based scenario-setting experiments by combining the observed and detrended climatic factors were utilized to quantify the effects of individual climatic factor(i.e.,temperature and precipitation).The results revealed that both temperature and precipitation had experienced increasing trends at most meteorological stations in Xinjiang from 1980 to 2020,especially the spring temperature and winter precipitation.Due to the influence of temperature,trends of intensifying drought have been observed at spring,summer,autumn,and annual scales.In addition,the drought trends in southern Xinjiang were more notable than those in northern Xinjiang.From 1980 to 2020,temperature trends exacerbated drought trends,but precipitation trends alleviated drought trends in Xinjiang.Most meteorological stations in Xinjiang exhibited temperature-dominated drought trend except in winter;in winter,most stations exhibited precipitation-dominated wetting trend.The findings of this study highlight the importance of the impact of temperature on drought in Xinjiang and deepen the understanding of the factors influencing drought.

Analysis of Temperature Trends and Variations in the Arabian Peninsula’s Upper Atmosphere

In this study, the trends of upper-air temperatures are analysed by utilising radiosonde observations for the barometric levels at 700, 500, 300, 200, 150, 100 and 50 hPa from five meteorological stations within the Arabian Peninsula from January 1986 to August 2015. The mean monthly variations of the temperatures at these levels are characterised and established. The magnitudes of the annual trends of the mean temperatures for each site for the selected barometric levels are studied and statistically tested using Mann-Kendall rank statistics at different significance levels. The temperature trends at different pressure levels show that the upper troposphere and lower stratosphere are warming, while the middle troposphere is cooling which is consistent with the findings of other studies. The variations in upper air temperature observed in this study can be attributed to a range of factors, including increasing greenhouse gas concentrations, changes in atmospheric circulation patterns, variations in solar activity, aerosols and volcanic eruptions, and land use and land cover change.

Temperature trends and elevation dependent warming during 1965-2014 in headwaters of Yangtze River, Qinghai Tibetan Plateau

The understanding of temperature trends in high elevation mountain areas is an integral part of climate change research and it is critical for assessing the impacts of climate change on water resources including glacier melt, degradation of soils, and active layer thickness. In this study, climate changes were analyzed based on trends in air temperature variables(Tmax, Tmin, Tmean), and Diurnal Temperature Range(DTR) as well as elevation-dependent warming at annual and seasonal scales in the Headwaters of Yangtze River(HWYZ), Qinghai Tibetan Plateau. The Base Period(1965-2014) was split into two subperiods;Period-Ⅰ(1965-1989) and Period-Ⅱ(1990-2014) and the analysis was constrained over two subbasins;Zhimenda and Tuotuohe. Increasing trends were found in absolute changes in temperature variables during Period-Ⅱ as compared to Period-Ⅰ.Tmax, Tmin, and Tmean had significant increasing trends for both sub-basins. The highest significant trends in annual time scale were observed in Tmin(1.15℃ decade-1) in Tuotuohe and 0.98℃ decade-1 in Zhimenda sub-basins. In Period-Ⅱ, only the winter season had the highest magnitudes of Tmax and Tmin0.58℃ decade-1 and 1.26℃ decade-1 in Tuotuohe subbasin, respectively. Elevation dependent warming analysis revealed that Tmax, Tmin and Tmean trend magnitudes increase with the increase of elevations in the middle reaches(4000 m to 4400 m) of the HWYZ during Period-Ⅱ annually. The increasing trend magnitude during Period-Ⅱ, for Tmax, is 1.77, 0.92, and 1.31℃ decade-1, for Tmin 1.20, 1.32 and 1.59℃ decade-1,for Tmean 1.51, 1.10 and 1.51℃ decade-1 at elevations of4066 m, 4175 m and 4415 m respectively in the winter season. Tmean increases during the spring season for> 3681 m elevations during Period-Ⅱ, with no particular relation with elevation dependency for other variables. During the summer season in Period Ⅱ, Tmax, Tmin, Tmean increases with the increase of elevations(3681 m to 4415 m) in the middle reaches of HWYZ. Elevation dependent warming(EDW), the study concluded that magnitudes of Tmin are increasing significantly after the 1990s as compared to Tmax in the HWYZ. It is concluded that the climate of the HWYZ is getting warmer in both sub-basins and the rate of warming was more evident after the 1990s. The outcomes of the study provide an essential insight into climate change in the region and would be a primary index to select and design research scenarios to explore the impacts of climate change on water resources.

Temperature Trends on Gran Canaria (Canary Islands). An Example of Global Warming over the Subtropical Northeastern Atlantic

The variation in temperature on the island of Gran Canaria is studied using the method applied to the nearby island of Tenerife [1]. An upward warming trend of 0.09°C ± 0.05°C (α = 0.01) was seen from 1946 to date, which has accelerated since the seventies to 0.17°C ± 0.10°C (α = 0.01). The increase was higher at night (0.11°C ± 0.05°C) than by day (0.08°C ± 0.06°C), so the temperature range decreased slightly. These values are similar to those of Tenerife and the time series of anomalies for the two islands are highly correlated. On the coast the same relationship to the sea surface temperature was found as in Tenerife, but in the mid-altitude areas to windward, some differences were detected that are hypothetically attributable to the different relief of the two islands.

Change Trends of Accumulated Temperature and Effects on Agricultural Production in Shenyang during Recent 58 Years

[Objective] The aim was to study the change trend of accumulated temperature in Shenyang in recent 58 years, as well as its effect on agricultural production. [Method] Based on the surface temperature data in Shenyang, the change trends of ≥0 ℃ and ≥10 ℃ accumulated temperature in Shenyang in recent 58 years were analyzed by means of climatic statistics method, and the effects of accumulated temperature variation on agricultural production were discussed. [Result] In recent 58 years, the first day with temperature ≥0 ℃ advanced 10 d, and the last day put off slightly, while sustained days prolonged 13 d, and ≥0 ℃ accumulated temperature increased by 343 ℃·d; meanwhile, the first day with temperature ≥10 ℃ advanced 9 d, and the last day put off 8 d, while sustained days prolonged 16 d, and ≥10 ℃ accumulated temperature increased by 370 ℃·d; compared with the first 20 years, sustained days with temperature ≥0 ℃ and ≥10 ℃ prolonged 9 d in the last 20 years, and ≥0 ℃ and ≥10 ℃ accumulated temperature increased by 196 and 202 ℃·d, respectively. In addition, the increase of heat resources affected agricultural production in Shenyang. [Conclusion] The study could provide theoretical foundation for grasping heat resources variation and adjusting agriculture distribution.

Future Extremes Temperature: Trends and Changes Assessment over the Mono River Basin, Togo (West Africa)

This study assessed the extreme temperatures trends and changes over Mono River Basin under the highest greenhouse gas emission scenario RCP8.5. Simulations of five (5) regional climate models (RCMs) provided by Africa-CORDEX program were selected from the eighth (8) considered. Future trends in temperature percentiles, including extremes, are used to assess changes in the distribution of daily temperature over Mono Basin in Togo. Changes of temperature and Extreme low (high) temperatures from the baseline period 1961-2010 were computed for future (2051-2100). This analysis reveals that in the north of the basin, for the positive trends, the maximum is 0.82°C·year-1 given by model MPI-ESM2 at Tchamba while the strongest negative change is 0.26°C·year-1 given by model MIROC at Sotouboua. In the south of the basin, the strongest negative trend is of 0.03°C·year-1 given by model (A) CNRM-CMA5. The maximum ones of the trends for models-mean are all positive except at Anié. Higher percentiles of minimum and maximum temperature will increase at a greater rate than the lower percentiles during dry and rainy seasons (with differences more pronounced for maximum values) over the north. Concerning future changes, almost all the RCMs predicted an increase of maximum and minimum temperatures over most parts of the Mono Basin, particularly in the north. Finally, results predicted an increase of TX90P (TX10P) and TN90P (TN10P) from 10% to 45% (13% to 40%) and 0% to 35% (12% Mean value), respectively over Mono Basin.

MODIS-Derived Nighttime Arctic Land-Surface Temperature Nascent Trends and Non-Stationary Changes

Arctic nighttime land-surface temperatures derived by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors onboard the NASA Terra and Aqua satellites are investigated. We use the local equator crossing times of 22:30 and 01:30, respectively, in the analysis of changes, trends and variations on the Arctic region and within 120° sectors. We show increases in the number of days above 0°C and significant increase trends over their decadal periods of March 2000 through 2010 (MODIS Terra) and July 2002 through 2012 (MODIS Aqua). The MODIS Aqua nighttime Arctic land-surface temperature change, +0.2°C ± 0.2°C with P-value of 0.01 indicates a reduction relative to the MODIS Terra nighttime Arctic land-surface temperature change, +1.8°C ± 0.3°C with P-value of 0.01. This reduction is a decadal non-stationary component of the Arctic land-surface temperature changes. The reduction is greatest, -1.3°C ± 0.2°C with P-value of 0.01 in the Eastern Russia— Western North American sector of the Arctic during the July 2002 through 2012.

Observed changes in surface air temperature and precipitation in the Hindu Kush Himalayan region over the last 100-plus years

In this paper, we analyzed the long-term changes in temperature and precipitation in the Hindu Kush Himalayan (HKH) region based on climate datasets LSAT-V1.1 and CGP1.0 recently developed by the China Meteorological Administration. The analysis results show that during 1901e2014 the annual mean surface air temperature over the whole HKH has undergone a significant increasing trend. We determined the change rates in the mean temperature, mean maximum temperature, and mean minimum temperature to be 0.104
C per decade, 0.077
C per decade, and 0.176
C per decade, respectively. Most parts of the HKH have experienced a warming trend, with the largest increase occurring on the Tibetan Plateau (TP) and south of Pakistan. The trend of precipitation for the whole HKH is characterized by a slight decrease during 1901e2014. During 1961e2013, however, the trend of the annual precipitation shows a statistically significant increase, with a rate of 5.28% per decade and has a more rapid increase since the mid-1980s. Most parts of northern India and the northern TP have experienced a strong increase in the number of precipitation days (daily rainfall 1 mm), whereas Southwest China and Myanmar have experienced a declining trend in precipitation days. Compared to the trends in precipitation days, the spatial pattern of trends in the precipitation intensity seems to be more closely related to the terrain, and the higher altitude areas have shown more significant upward trends in precipitation intensity during 1961e2013.

The changing process and trend of ground temperature around tower foundations of Qinghai-Tibet Power Transmission line

After the construction of Qinghai-Tibet Highway and Railway, the Qinghai-Tibet Power Transmission(QTPT) line is another major permafrost engineering project with new types of engineering structures. The changing process and trend of ground temperature around tower foundations are crucial for the stability of QTPT. We analyzed the change characteristics and tendencies of the ground temperature based on field monitoring data from 2010 to 2014. The results reveal that soil around the tower foundations froze and connected with the artificial permafrost induced during the construction of footings after the first freezing period, and the soil below the original permafrost table kept freezing in subsequent thawing periods. The ground temperature lowered to that of natural fields, fast or slowly for tower foundations with thermosyphons,while for tower foundations without thermosyphons, the increase in ground temperature resulted in higher temperature than that of natural fields. Also, the permafrost temperature and ice content are significant factors that influence the ground temperature around tower foundations. Specifically, the ground temperature around tower foundations in warm and ice-rich permafrost regions decreased slowly, while that in cold and ice poor permafrost regions cooled faster. Moreover, foundations types impacted the ground temperature, which consisted of different technical processes during construction and variant of tower footing structures. The revealed changing process and trend of the ground temperature is beneficial for evaluating the thermal regime evolution around tower foundations in the context of climate change.

Trends in extreme high temperature at different altitudes of Southwest China during 1961–2014

This study analyzed the trends in extreme high temperature in Southwest China based on the observed daily maximum temperature and average temperature data from 410 Chinese stations recently released by the China Meteorological Administration.The authors found that the trends in extreme high temperature at different altitudes of Southwest China exhibit staged variations during a recent 50-year period(1961–2014).The trends in mean temperature and maximum temperature also exhibit phase variation.All temperature-related variables increase gently during the period 1975–94,whereas they increase dramatically during the recent period of 1995–2014,with a rate that is approximately two to ten times more than that during 1975–94.In addition,the trends in mean temperature,maximum temperature,and the frequency of extreme high temperature in the low altitudes transit from negative to positive in the two periods,while they increase dramatically in the mid-and high-altitude areas during 1995–2014,the well-known global warming hiatus period.In particular,the maximum temperature increases much faster than that of average temperature.This result implies that the regional temperature trend could be apparently different from the global mean temperature change.

Analysis of Monthly, Seasonal and Annual Air Temperature Variability and Trends in Taiz City - Republic of Yemen

Climate change is one of the most important issues of today’s World. Climate scientists have concluded that the earth’s surface air temperature warmed by 0.6 ± 0.2℃ during the 20th century, accompanied by changes in the hydrologic cycle. Of all the climate elements, temperature plays a major role in detecting climate change brought about by urbanization and industrialization. This study focuses on the variability and trends of the mean annual, seasonal and monthly surface air temperature in Taiz city, Republic of Yemen, during the period 1979-2006. The results of the analysis of the whole period reveal a statistically significant increasing trend in practically all the months and seasons. A tendency has also been observed towards warmer years, with significantly warmer summer and spring periods and slightly warmer autumn and winter, an increase of 1.79℃ and 1.18℃ has been observed in the mean summer and mean winter temperature, respectively. Positive trends of about 1.5℃ in the annual mean temperature were found for the whole period. The air temperature time series are analyzed, so that the variability and trends can be described.

Variations Trend of Soil Temperature at Deep Layers in Xining from 1961 to 2010

[Objective] The aim was to analyze the changes trend of mean earth temperature at 0.8, 1.6 and 3.2 m deep to the ground in Xining from 1961 to 2010. [Method] Using the data of monthly mean soil temperatures at 0.8,1.6 and 3.2 m in Xining from 1961 to 2010, the linear trend, climatic anomalous and climate abrupt of deep soil temperature during recent 50 years were analyzed by using of linear trend analysis, accumulated variance and signal noise ratio methods. [Result] In terms of linear trend, the annual mean soil temperatures at 0.8 m in recent 50 years, as well as 1.6 and 3.2 m in recent 45 years displayed a weak increasing trend in Xining. Comparing with the average air temperature in the same period, the rising range of deep soil temperature is obvious less. The average soil temperatures at 0.8 m was the highest in 1980s, but it was the lowest in the 1960s. In spring, autumn and winter in the 1980s, the average soil temperature was a little higher than many other years at 1.6 m. In four seasons in the 1980s, the average soil temperature was obvious higher at 3.2 m. The annual soil temperatures at 0.8 m were anomalous warm in 1991, and from 1987 to 1992, as well as in 1994, 2007 and 2009. The annual soil temperatures at 3.2 m were anomalous warm. In the 1990s, there were four years which were anomalous warm at 3.2 m, as well as five years at 0.8 m and five years at 1.6 m. [Conclusion] The study provided theoretical basis for the development of climate changes in Xining.

Sea Surface Temperature Extremes of Different Intensity in the China Seas During the Global Warming Acceleration and Hiatus Periods

Based on the daily OISST V2 with 0.25ohorizontal resolutions, the present study looks into the variations of sea surface temperature (SST) extremes in the China Seas for different segments of the period 1982-2013. The two segments include the warming acceleration period from 1982 to 1997 and the hiatus period from 1998 to 2013 when the global mean surface temperature (GMST) did not significantly increase as expected, or even decreased in some areas.First, we construct the regional average time series over the entire China Seas (15°-45°N, 105°-130°E) for these SST extremes. During the hiatus period, the regionally averaged 10th, 1th and 0.1th percentile of SSTs in each year decreased significantly by 0.40℃, 0.56℃ and 0.58℃ per decade, respectively. The regionally averaged 90th, 99th and 99.9th percentile of SSTs in each year decreased slightly or insignificantly. Our work confirm that the regional hiatus was primarily reflected by wintertime cold extremes. Spatially, the trends of cold extremes in different intensity were nonuniformly distributed. Cold extremes in the near-shore areas were much more sensitive to the global warming hiatus. Hot extremes exhibited non-significant trend in the China Seas during the hiatus period. In short, the variations of the SST extremes in the two periods were non-uniform spatially and asymmetric seasonally. It is unexpected that the hot and cold extremes of each year during 1998-2013 were still higher than those extremes during 1982-1997. It is obvious that compared with the warming acceleration period, hot extremes were far more likely to occur in the recent hiatus as a result of a 0.3℃ warmer shift in the mean temperature distribution. Moreover, hot extremes in the China Seas will be sustained or amplified with the end of warming hiatus and the continuous anthropogenic warming.

Trend Analysis of the Mean Annual Temperature in Rwanda during the Last Fifty Two Years

Climate change and global warming are widely recognized as the most significant environmental dilemma the world is experiencing today. Recent studies have shown that the Earth’s surface air temperature has increased by 0.6°C - 0.8°C during the 20th century, along with changes in the hydrological cycle. This has alerted the international community and brought great interest to climate scientists leading to several studies on climate trend detection at various scales. This paper examines the long-term modification of the near surface air temperature in Rwanda. Time series of near surface air temperature data for the period ranging from 1958 to 2010 for five weather observatories were collected from the Rwanda National Meteorological Service. Variations and trends of annual mean temperature time series were examined. The cumulative sum charts (CUSUM) and bootstrapping and the sequential version of the Mann Kendall Rank Statistic were used for the detection of abrupt changes. Regression analysis was performed for the trends and the Mann-Kendall Rank Statistic Test was used for the examination of their significance. Statistically significant abrupt changes and trends have been detected. The major change point in the annual mean temperature occurred around 1977-1979. The analysis of the annual mean temperature showed for all observatories a not very significant cooling trend during the period ranging from 1958 to 1977-1979 while a significant warming trend was furthermore observed for the period after the 1977-1979 where Kigali, the Capital of Rwanda, presented the highest values of the slope (0.0455/year) with high value of coefficient of determination (R2 = 0.6798), the Kendall’s tau statistic (M-K = 0.62), the Kendall Score (S = 328) with a two-sided p-value far less than the confidence level α of 5%). This is most likely explained by the growing population and increasing urbanization and industrialization the country has experienced, especially the Capital City Kigali, during the last decades.

Observed Trends in Extreme Temperature over the Klang Valley, Malaysia

This study investigates the recent extreme temperature trends across 19 stations in the Klang Valley, Malaysia, over the period 2006^-16. Fourteen extreme index trends were analyzed using the Mann-Kendall non-parametric test, with Sen’s slope as a magnitude estimator. Generally, the annual daily mean temperature, daily mean maximum temperature, and daily mean minimum temperature in the Klang Valley increased significantly, by 0.07°C yr^-1, 0.07°C yr^-1 and 0.08°C yr^-1, respectively. For the warm temperature indices, the results indicated a significant upward trend for the annual maximum of maximum temperature, by 0.09°C yr^-1, and the annual maximum of minimum temperature, by 0.11°C yr^-1. The results for the total number of warm days and warm nights showed significant increasing trends of 5.02 d yr^-1 and 6.92 d yr^-1, respectively. For the cold temperature indices, there were upward trends for the annual minimum of maximum temperature, by 0.09°C yr^-1, and the annual minimum of minimum temperature, by 0.03°C yr^-1, concurrent with the decreases in the total number cold days (TX10P), with -3.80 d yr^-1, and cold nights (TN10P), with -4.33 d yr^-1. The 34°C and 37°C summer days results showed significant upward trends of 4.10 d yr^-1 and 0.25 d yr^-1, respectively. Overall, these findings showed upward warming trends in the Klang Valley, with the minimum temperature rate increasing more than that of the maximum temperature, especially in urban areas.

Variation Characteristics and Trends of Temperature and Evaporation in Huanren County in Recent 60 Years

Based on the data of daily average temperature and evaporation in Huanren County from 1953 to 2012, the changing characteristics and trends of temperature and evaporation were analyzed by using climatic tendency rate and sliding Ttest method. The results showed that annual av- erage temperature in Huanren County showed a significant increasing trend in recent 60 years, and its linear tendency rate was 0.26 ℃/10 a. Tem- perature increase was in other seasons except for summer. There was a sudden change in annual average temperature in 1987, and winter average temperature changed suddenly in 1969 and 1985, while there were no sudden changes in average temperature in other seasons. Annual average evaporation also decreased, and its linear trend rate was -8.19 mm/10 a; average evaporation tended to decrease in spring and summer and in- creased in autumn and winter. In a word, the climate tended to be warm and dry in Huanren County.

Analysis of Changing Characteristics and Trends of Temperature and Precipitation in Yanshi City in Recent 50 Years

Based on meteorological observation data of temperature and precipitation in Yanshi City from 1961 to 2010, annual and interdecadal variations of annual average temperature, annual average maximum temperature, annual average minimum temperature, and annual average pre- cipitation in Yanshi City in recent 50 years were analyzed, and then M-K test of changing trend of annual average temperature was conducted. The results showed that from 1961 to 2010, annual average temperature, annual average maximum temperature and annual average minimum tempera- ture showed a significantly increasing trend in Yanshi City, rising by 0.30, 0.20 and 0.50 ~（3/10 a respectively. Annual average temperature was the lowest in the 1970s and the highest in 2000 -2010. There was a sudden change in annual average temperature in 1995. In the 50 years, annual av- erage precipitation in Yanshi City increased by 1.8 mm/10 a, but the increase was not significant. The minimum of annual average precipitation 511.3 mm appeared in the 1960s, while the maximum 553.2 mm appeared in 2000 -2010.

Trends of summertime extreme temperatures in the Arctic

Extreme temperature events can influence the natural environment and societal activities more so than mean temperature events. This study used daily data from 238 stations north of 60°N, obtained from the Global Summary of the Day dataset for the period 1979~015, to investigate the trends of summertime extreme temperature. The results revealed most stations north of 60°N with trends of decrease in the number of cold days （nights） and increase in the number of warm clays （nights）. The regional average results showed trends of consistent decline （rise） of cold days and nights （warm days and nights） in Eurasia and Greenland. Similarly, the trends of the seasonal maximum and minimum values were most significant in these regions. In summer, of three indices considered （i.e., Arctic Oscillation, Arctic dipole, and E1 Nifi^Southem Oscillation）, the largest contributor to the trends of extreme temperature events was the Arctic dipole. Prevailing southerly winds in summer brought warm moist air across northern Eurasia and Greenland, conducive to increased numbers of warm days （nights） and decreased numbers of cold day （nights）. Moreover, we defined extreme events using different thresholds and found the spatial distributions of the trends were similar.