[Objective] This study aimed to analyze the characteristics of temperature variation in Zhangqiu City during the past 30 years. [Method] Variation characteristics of average annual maximum temperature, average annual ...[Objective] This study aimed to analyze the characteristics of temperature variation in Zhangqiu City during the past 30 years. [Method] Variation characteristics of average annual maximum temperature, average annual temperature and average annual minimum temperature in Zhangqiu City during the past 30 years were analyzed by using related temperature data during 1981 -2010 collected from National Meteorological Observation Station in Zhangqiu. [Result] Average annual maximum temperature, average annual temperature and average annual minimum temperature in Zhangqiu City showed an upward trend; average annual minimum temperature showed the most significant increasing tendency, with a tendency rate of 1.347 ℃/10 a; followed by average annual temperature; average annual maximum temperature showed the slowest increasing tendency, with a tendency rate of 0.062 ℃/10 a, indicating that the increase of average annual temperature mainly depended on the contribution of average annual minimum temperature. [Conclusion] This study provides reference and scientific basis for climate change monitoring, diagnosis, assessment, forecast and decision-making in Zhangqiu City.展开更多
Based on simulations of 18 CMIP5 models under three RCP scenarios, this article investigates changes in mean temperature and precipitation and their extremes over Asia in the context of global warming targets of 1.5-4...Based on simulations of 18 CMIP5 models under three RCP scenarios, this article investigates changes in mean temperature and precipitation and their extremes over Asia in the context of global warming targets of 1.5-4 ℃, and further compares the differences between 1.5 ℃ and 2 ℃ targets. Results show that relative to the pre-industrial era, the mean temperature over Asia increases by 2.3 ℃, 3.0 ℃, 4.6 ℃, and 6.0 ℃ at warming targets of 1.5 ℃, 2 ℃, 3 ℃, and 4 ℃, respectively, with stronger warming in high latitudes than in low latitudes. The corresponding enhancement in mean precipitation over the entire Asian region is 4.4%, 5.8%, 10.2%, and 13.0%, with significant regional differences. In addition, an increase in warm extremes, a decrease in cold extremes, and a strengthening in the variability of amounts of extreme precipitation are projected. Under the 1.5 ℃ target, compared with the climate under the 2 ℃ target, the mean temperature will be lower by 0.5-1 ℃ over Asia; the mean precipitation will be less by 5%-20% over most of Asia, but will be greater by about 10%-15% over West Asia and western South Asia; extreme high temperatures will be uniformly cooler throughout the Asian region, and the warming in extreme low temperatures will decrease significantly in high latitudes of Asia; extreme precipitation will be weaker over most of Asia but will be stronger over West Asia and western South Asia. Under the 1.5 ℃ and 2 ℃ warming targets, the probability of very hot weather (anomalies greater than 1σ, σ is standard deviation), extremely hot weather (anomalies greater than 3or), and extremely heavy precipitation (anomalies greater than 3σ) occurring will increase by at least once, 10%, and 10%, respectively, compared to the reference period (1861-1900).展开更多
Change related to climate in Macao was studied on the basis of daily temperature observations over the period 1901-2007. The result shows that annual mean surface air temperature in Macao as a whole rose with a warmin...Change related to climate in Macao was studied on the basis of daily temperature observations over the period 1901-2007. The result shows that annual mean surface air temperature in Macao as a whole rose with a warming rate of about 0.066℃ per 10 years in the recent 107 years. The most evident warming occurred in spring and winter. The interdecadal variations of the seasonal mean temperature in summer and winter appeared as a series of waves with a time scale of about 30 years and 60 years, respectively. The annual mean minimum temperature increased about twice as fast as the annual mean maximum temperature, resulting in a broad decline in the annual mean diurnal range. The interdecadal variations of annual mean maximum temperature are obviously different from those of annual mean minimum temperature. It appears that the increase in the annual mean maximum temperature in the recent 20 years may be part of slow climate fluctuations with a periodicity of about 60 years, whereas that in the annual mean minimum temperature appears to be the continuation of a long-term warming trend.展开更多
Monthly temperature and precipitation time-series for the Zhujiang River Basin are analyzed in order to identify changes in climate extremes. Daily temperature and precipitation data from 1961 to 2007 of 192 meteorolo...Monthly temperature and precipitation time-series for the Zhujiang River Basin are analyzed in order to identify changes in climate extremes. Daily temperature and precipitation data from 1961 to 2007 of 192 meteorological stations are used. Two temperature indicators (monthly mean and monthly maximum mean) and three precipitation indicators (monthly total, monthly maximum consecutive 5-day precipitation, and monthly dry days) are analyzed. Tendencies in all five indicators can be observed. Many stations show significant positive trends (above the 90% confidence level) for monthly mean temperatures and monthly maximum mean temperatures. For all months, a significant increase in temperature from 1961 to 2007 can be observed in the entire basin with the coastal area in particular. Positive trends of precipitation extremes can be observed from January to March. Negative trends are detected from September to November. The number of dry days in October increased significantly at 40% of all meteorological stations. Stations with changes of monthly precipitation extremes are scattered over the Zhujiang River Basin. An aggregation of heat waves and droughts can be detected which is accompanied by significant increases of temperature extremes and the negative tendencies in precipitation extremes. The detection of tendencies in climate station density. extremes essentially relies on a good data quality and high展开更多
On 1 April 2017 China established Xiongan New Area in Hebei Province, which was described as ‘a strategy crucial for a millennium to come'. A point of interest for the public is to be aware of the historical climate...On 1 April 2017 China established Xiongan New Area in Hebei Province, which was described as ‘a strategy crucial for a millennium to come'. A point of interest for the public is to be aware of the historical climate change in this new area; however, results from previous global-scale or largerregional-scale averages provide relatively limited information because of the distinct regional differences in climate change. This study analyzes the changes in mean and extreme temperature in this area, based on homogenized daily temperature data for the period 1960–2016. The results show a significant warming in the indices of annual, summer, and winter mean temperature(Tmean), maximum temperature(Tmax), and minimum temperature(Tmin). The linear rate of annual Tmean is 0.34 °C/decade. Temperatures on the hottest day, the warmest night, the coldest day, and the coldest night, every year, all show increasing trends, with the trends in the two nighttime-related indices being significant. An increasing occurrence of warm days, warm nights, hot days, and tropical nights, but a decreasing occurrence of cold days, cold nights, icing days, and frost days, are found, all of which are significant, except for the occurrences of hot days and icing days. A significant extension of the length of the thermal growing season is also found. The magnitudes of change in most of the temperature indices in Xiongan New Area are larger than those of the adjacent Jing-Jin-Ji and North China regional mean. These results could provide valuable information for policymakers, city planners, engineers, and migrants to this new area.展开更多
Based on the observations from 239 meteorological stations located in Central China (Henan, Hubei and Hunan provinces), this paper focuses on the climate change facts during 1961- 2010. There was a significant incre...Based on the observations from 239 meteorological stations located in Central China (Henan, Hubei and Hunan provinces), this paper focuses on the climate change facts during 1961- 2010. There was a significant increasing trend in annual mean temperature for Central China during 1961 -2010. The increasing rate was 0.15℃ per decade, which was lower than the national trend. Since the mid-1980s, temperature increasing was obvious. Large increasing rate was observed in the mid-eastern part of Central China. For the four seasons, the increasing rate in winter was the largest (0.27℃ per decade). The increasing rate in the annual mean minimum temperature was larger than that in the annual mean maximum temperature from 1961 to 2010. As a result, the diurnal range of temperature decreased at the rate of -0.10℃ per decade. The extreme high temperature events were increasing while the extreme low temperature events were significantly decreasing. There was no obvious trend in annual precipitation for Central China during 1961-2010. Precipitation in summer and winter significantly increased; change of precipitation in spring was not obvious; precipitation in autumn was decreasing. The decreasing rate of annual rainy days was -3.4 d per decade. The precipitation intensity increased at the rate of 0.25 mm d-1 per decade. Heavy-rain days significantly increased. Spring and summer started earlier while autumn and winter started later. As a result, spring and summer duration was expanding whereas autumn and winter duration shortened.展开更多
By using the observation data from 89 weather stations in Xinjiang during 1961-2010, this paper analyzed the basic climatic elements including temperature, precipitation, wind speed, sunshine duration, water vapor pre...By using the observation data from 89 weather stations in Xinjiang during 1961-2010, this paper analyzed the basic climatic elements including temperature, precipitation, wind speed, sunshine duration, water vapor pressure, and dust storm in the entire Xinjiang and the subareas: North Xinjiang, Tianshan Mountains, and South Xinjiang. The results indicate that from 1961 to 2010 the annual and seasonal mean temperatures in the entire Xinjiang show an increasing trend with the increasing rate rising from south to north. The increasing rate of annual mean minimum temperature is over twice more than that of the annual mean maximum temperature, contributing much to the increase in the annual averages. The magnitude of the decrease rate of low-temperature days is larger than the increase rate of high-temperature days. The increase of warm days and warm nights and the decrease of cold days and cold nights further reveal that the temperature increasing in Xinjiang is higher. In addition, annual and seasonal rainfalls have been increasing. South Xinjiang experiences higher increase in rainfall amounts than North Xinjiang and Tianshan Mountains. Annual rainy days, longest consecutive rainy days, the daily maximum precipitation and extreme precipitation events, annual torrential rain days and amount, annual blizzard days and amount, all show an increasing trend, corresponding to the increasing in annual mean water vapor pressure. This result shows that the humidity has increased with temperature increasing in the past 50 years. The decrease in annual mean wind speed and gale days lessen the impact of dust storm, sandstorm, and floating dust events. The increase in annual rainy days is the cause of the decrease in annual sunshine duration, while the increase in spring sunshine duration corresponds with the decrease in dust weather. Therefore, the increase in precipitation indicators, the decrease in gales and dust weather, and the increasing in sunshine duration in spring will be beneficial to crops growth.展开更多
To explore the energy saving effect of building envelope, the experiments were carried out through a comparison of basic cubicle in summer. Experiments show that if energy efficiency measures are applied only in the e...To explore the energy saving effect of building envelope, the experiments were carried out through a comparison of basic cubicle in summer. Experiments show that if energy efficiency measures are applied only in the external walls and windows, the energy saving cubicles have an average energy efficiency ratio of 27.75% and 27.05% when the air change rates are 1.1 and 1.4 h-1 in summer, with both values being over the standard target value by 25%. And the indoor air temperature of the energy saving cubicle is below that of the basic cubicle. The daily mean temperature difference between the interior surface of insulation wall and no insulation reaches 1.47℃, and the mean temperature difference is up to 8.52℃ between the interior surface and exterior surface of insulating glass and single glass. The two cubicles were simulated for energy consumption using VisualDOE4.0 software under real weather conditions in summer. The results show that the mean deviation is 10.02% between experimental and simulated energy efficiency ratio. The correctness and validity of simulation results of the VisualDOE4.0 software are proved.展开更多
In this study, observational data from 141 meteorological stations in Northwest China, including temperature, precipitation, dust storm, gale days and wind speed, were analyzed statistically to gain insight of the fea...In this study, observational data from 141 meteorological stations in Northwest China, including temperature, precipitation, dust storm, gale days and wind speed, were analyzed statistically to gain insight of the features of basic climate index and extreme climate events. The results showed that the annual mean temperature and seasonal mean temperature rose significantly, and the rising rate of the annual mean temperature is 0.27℃ per decade; the extreme high temperature days have increased; the interdecadal change of annual precipitation is marked, and the precipitation in winter and summer increased slightly, while decreased slightly in spring and autumn. The annual precipitation increased in the area west of the Yellow River, whereas decreased in the area east of the river. The drought had an increasing trend. There were 17 droughts during 1961-2010, and 10 droughts from 1991 to 2010. The number of droughts in spring and autumn increased, while decreased in summer.展开更多
The world is facing a big challenge of climatic change, mainly due to increasing concentrations of GHGs (greenhouse gases) in the atmosphere. Many researches indicated that the climate change occurred disproportiona...The world is facing a big challenge of climatic change, mainly due to increasing concentrations of GHGs (greenhouse gases) in the atmosphere. Many researches indicated that the climate change occurred disproportionately on developing countries such as MENA (Middle East and North Africa) countries. The climatic model CGCM3.1 (T47) 2 is used in this research to explain the changes in average temperatures and the rainfall on the MENA region with special emphases on Iraq. Historical records (1900-2009) and future (2020-2099) were studied and compared; each period was divided to four sub-periods of thirty years. The results showed that the average monthly temperature for the four historical periods fluctuated between the lowest and highest value as follows: 9.2-32.9, 10.3-32.7, 9.3-32.8 and 8.6-33.9 (℃). The rainfall for historical periods kept on the same distribution during the past 109 years, and fluctuated between the lowest and highest value of 21.3 mm and 37.6 mm with an average that reached up to 26.51 mm. For the future period, the maximum average monthly temperature reached up to 37.41 (℃) during June and minimum average monthly temperature reached up to 4.24 (℃) during January. The average monthly temperature fluctuated giving a clear impression that the future portends a higher temperature. The average monthly rainfall, for the future period, fluctuated between the lowest and highest value of 12.91 mm and 20.63 mm with an average that reached 16.84 mm which represent a reduction percentage of about 36.47% relative to the historical record of rainfall for the sanae months.展开更多
The observed global mean temperature is the highest on record for the past decade but has plateaued to form an apparent"hiatus"in global temperature rise,with an almost zero short-term trend. Several speaker...The observed global mean temperature is the highest on record for the past decade but has plateaued to form an apparent"hiatus"in global temperature rise,with an almost zero short-term trend. Several speakers presented results on the hiatus and suggested possible mechanisms.展开更多
The results from three methods aimed at improving precipitation type (e.g., rain, sleet, and snow) estimation are presented and compared in this paper. The methods include the threshold air temperature (AT), thres...The results from three methods aimed at improving precipitation type (e.g., rain, sleet, and snow) estimation are presented and compared in this paper. The methods include the threshold air temperature (AT), threshold wet bulb temperature (WBT) and Koistinen and Saltikoff (KSS) methods. Dot graphs are plotted to acquire the threshold air temperature or the threshold wet bulb temperature using daily averaged air temperature, wet bulb temperature and precipitation data at 643 stations from 1961 to 1979 (precipitation types are not labeled in the database from 1980 to present) in China. The results indicate that the threshold AT or WBT methods are not able to differentiate rain, sleet and snow in the most regions in China; sleet is difficult to differentiate from other precipitation types based on the two threshold methods. Therefore, one threshold AT and WBT method was used in this study to differentiate rain and snow. Based on Gaussian- Kriging interpolation of threshold air temperature (To) and wet bulb temperature (Tw), the To and Tw contour lines and contour surfaces are calculated for China. Finally, a comparison between the KSS, AT and WBT methods are provided in which the KSS method is calculated based on air temperature and relative humidity. The results suggest that the KSS method is more appropriate for water phase estimation than are the other methods; the maximum precision for rain and snow is 99% and 94%, respectively. The AT method performs better than the WBT method when the critical air temperature is 2℃.展开更多
Daily climate data at 110 stations during 1961-2010 were selected to examine the changing characteristics of climate factors and extreme climate events in South China. The annual mean surface air temperature has incre...Daily climate data at 110 stations during 1961-2010 were selected to examine the changing characteristics of climate factors and extreme climate events in South China. The annual mean surface air temperature has increased significantly by 0.16℃ per decade, most notably in the Pearl River Delta and in winter. The increase rate of the annual extreme minimum temperature (0.48℃ per decade) is over twice that of the annual extreme maximum temperature (0.20℃ per decade), and the increase of the mean temperature is mainly the result of the increase of the extreme minimum temperature. The increase rate of high-temperature days (1.1 d per decade) is close to the decrease rate of low-temperature days (-1.3 d per decade). The rainfall has not shown any significant trend, but the number of rainy days has decreased and the rain intensity has increased. The regional mean sunshine duration has a significant decreasing trend of -40.9 h per decade, and the number of hazy days has a significant increasing trend of 6.3 d per decade. The decrease of sunshine duration is mainly caused by the increase of total cloud, not by the increase of hazy days in South China. Both the regional mean pan evaporation and mean wind speed have significant decreasing trends of -65.9 mm per decade and -0.11 m s-1 per decade, respectively. The decrease of both sunshine duration and mean wind speed plays an important role in the decrease of pan evaporation. The number of landing tropical cyclones has an insignificant decreasing trend of -0.6 per decade, but their intensities show a weak increasing trend. The formation location of tropical cyclones landing in South China has converged towards 10-19°N, and the landing position has shown a northward trend. The date of the first landfall tropical cyclone postpones 1.8 d per decade, and the date of the last landfall advances 3.6 d per decade, resulting in reduction of the typhoon season by 5.4 d per decade.展开更多
Using numerical model simulations, global surface temperature is projected to increase by l^C to 4~C during the 21 st century, primarily as a result of increasing concentrations of greenhouse gases. In the present stu...Using numerical model simulations, global surface temperature is projected to increase by l^C to 4~C during the 21 st century, primarily as a result of increasing concentrations of greenhouse gases. In the present study, a predictive technique incorporating driving forces into an observation time series was used to project the global mean surface temperature under four representative sce- narios of future emissions over the 21st century.展开更多
We studied the impact of sea surface temperature anomaly(SSTA) in the Japan Sea and the sea area east of Japan on the winter rainfall and air temperature in Northeast(NE) China using the singular value decomposition(S...We studied the impact of sea surface temperature anomaly(SSTA) in the Japan Sea and the sea area east of Japan on the winter rainfall and air temperature in Northeast(NE) China using the singular value decomposition(SVD) and empirical orthogonal function(EOF). The monthly-mean rainfall data observed at 160 stations in China, monthly-mean sea surface temperature(SST) of the Hadley Center for Climate Prediction and Research and monthly-mean air temperature from the NCEP reanalysis during 1960–2011 were used. Correlation analysis indicates that the SSTAs in the Japan Sea in September may last for three or four months and are an important index for forecasting the winter rainfall and air temperature in NE China. Positive SSTAs in the central Japan Sea and in the sea area east of Tokyo correspond to positive rainfall anomaly and negative air temperature anomaly in NE China. With the rise of SST in the Japan Sea, a weak cyclone appears over the Japan Sea. The northeasterly wind transports water vapor from the Okhotsk to NE China, resulting in more rainfall and lower air temperature. Negative SSTA years are accompanied by warmer air temperature and less snow in NE China. The 1000 h Pa geopotential height anomaly and wind anomaly fields are simulated by IAP-9L model, which supports the analysis results.展开更多
An experimental investigation was conducted to measure the temperature variation across the flow channel and to determine the performance of a natural convection solar air heater at various tilt angles from 15, 30 and...An experimental investigation was conducted to measure the temperature variation across the flow channel and to determine the performance of a natural convection solar air heater at various tilt angles from 15, 30 and 45°. The results of the temperature profile across the air gap showed that heat transfer from the absorber plate to the air stream was mainly by convection. At a particular section, mean air temperature could be calculated from the arithmetic mean of the temperature profile across the air gap to within ± 2 ℃. The axial air temperature distribution was non linear and did not increase much beyond 1 m of collector length. It tended to decrease towards the end of the collector. Overall glass, absorber plate and mean air temperatures over the entire length of the solar air heater could be determined by averaging the mean axial temperatures to within ± 2 ℃. The heater performed better as inclination increased.展开更多
Changes of air temperatures and atmosphere circulation at three high mountainous stations in Bulgaria are investigated for the period of 1941-2008.The three stations are located on peaks Musala,Cherni vrah and Botev,w...Changes of air temperatures and atmosphere circulation at three high mountainous stations in Bulgaria are investigated for the period of 1941-2008.The three stations are located on peaks Musala,Cherni vrah and Botev,where air temperature data have good quality.Some missing data were recovered using the method of differences. A significant mean annual air temperature rise happened in high mountainous parts of Bulgaria- the warming is in the order of 0.7°C for the entire period.The increase is very prominent particularly in the last 30 years.Main contributors to this overall tendency are summer months-June,July and August.To some degree,January also could be included in this group.November trend shows temperature rise at the beginning of the investigated period.One of the causes for such a tendency is atmosphere circulation in respective months.It also shows signs of considerable reorganization in both winter and summer.There is an increase of the cases of warm atmosphere patterns typical for winter, summer and autumn seasons in Bulgaria.Meridional circulation has essential significance for air temperatures during the cold half of the year.In January and June atmosphere circulation has a substantial influence on the thermal regime of air in high mountains of Bulgaria.In July,August and November this influence is reduced.There are no cycles in air temperatures for the investigated period.展开更多
The purpose of this paper is to present a simple way to approximate the dependence of the global mean air temperature at Earth's surface on atmospheric concentration of carbon dioxide. Current discussions include ene...The purpose of this paper is to present a simple way to approximate the dependence of the global mean air temperature at Earth's surface on atmospheric concentration of carbon dioxide. Current discussions include energy aspects of the greenhouse effect and the global warming. The starting point for the research are laws of thermodynamics, energy equilibrium and absorption and emission property of the atmosphere. According to the calculations, the natural and the anthropogenic changes effect the atmosphere. By the year 2100 the CO2 concentration will be doubled in comparison with the value of the pre-industrial ages. The doubled CO2 concentration will mean a temperature change about 1 ℃-1.5 ℃.展开更多
The data observed by a spectral airglow temperature imager (SATI) at Beijing National Observatory of Space Environment from July 23, 2008 to July 3l, 2009 are used to study night mesopause temperature in Beijing. Fr...The data observed by a spectral airglow temperature imager (SATI) at Beijing National Observatory of Space Environment from July 23, 2008 to July 3l, 2009 are used to study night mesopause temperature in Beijing. From variations of temperature at 87 and 94 km obtained from OH (6-2) and 02 (0-1) airglow spectra, temperature at night is shown lowest in the summer and highest in the winter. In summer, average temperature at 87 km is 173.9 K, lower than average temperature 180.1 K at 94 km. But in winter, average temperature at 87 Ion is 201.2 K, higher than average temperature 194.8 K at 94 kin. The altitude of mesopause in Beijing is below 87 km in summer and above 94 km in winter. There are about 120-150 days when the mesopause locates below 87 km, which is in agreement with the results of SABER/TIMED. Variations of temperatures at 87 and 94 km are analyzed by harmonic method. Our results show that amplitudes of annual oscillation of temperature at 87 and 94 km are 17.5 and 7.8 K respectively. Amplitudes of semi-annual oscillation at 87 and 94 km are 1.6 and 5.3 K, which are smaller than those of annual oscillation. Although there are differences among different observations because of different locations and different instruments, our results are in general agreement with observation at similar latitude as Beijing.展开更多
文摘[Objective] This study aimed to analyze the characteristics of temperature variation in Zhangqiu City during the past 30 years. [Method] Variation characteristics of average annual maximum temperature, average annual temperature and average annual minimum temperature in Zhangqiu City during the past 30 years were analyzed by using related temperature data during 1981 -2010 collected from National Meteorological Observation Station in Zhangqiu. [Result] Average annual maximum temperature, average annual temperature and average annual minimum temperature in Zhangqiu City showed an upward trend; average annual minimum temperature showed the most significant increasing tendency, with a tendency rate of 1.347 ℃/10 a; followed by average annual temperature; average annual maximum temperature showed the slowest increasing tendency, with a tendency rate of 0.062 ℃/10 a, indicating that the increase of average annual temperature mainly depended on the contribution of average annual minimum temperature. [Conclusion] This study provides reference and scientific basis for climate change monitoring, diagnosis, assessment, forecast and decision-making in Zhangqiu City.
基金Acknowledgments This research was jointly supported by the National Key Research and Development Program of China (2016YFA0600701), the National Natural Science Foundation of China (41675069), and the Climate Change Specific Fund of China (CCSF201731).
文摘Based on simulations of 18 CMIP5 models under three RCP scenarios, this article investigates changes in mean temperature and precipitation and their extremes over Asia in the context of global warming targets of 1.5-4 ℃, and further compares the differences between 1.5 ℃ and 2 ℃ targets. Results show that relative to the pre-industrial era, the mean temperature over Asia increases by 2.3 ℃, 3.0 ℃, 4.6 ℃, and 6.0 ℃ at warming targets of 1.5 ℃, 2 ℃, 3 ℃, and 4 ℃, respectively, with stronger warming in high latitudes than in low latitudes. The corresponding enhancement in mean precipitation over the entire Asian region is 4.4%, 5.8%, 10.2%, and 13.0%, with significant regional differences. In addition, an increase in warm extremes, a decrease in cold extremes, and a strengthening in the variability of amounts of extreme precipitation are projected. Under the 1.5 ℃ target, compared with the climate under the 2 ℃ target, the mean temperature will be lower by 0.5-1 ℃ over Asia; the mean precipitation will be less by 5%-20% over most of Asia, but will be greater by about 10%-15% over West Asia and western South Asia; extreme high temperatures will be uniformly cooler throughout the Asian region, and the warming in extreme low temperatures will decrease significantly in high latitudes of Asia; extreme precipitation will be weaker over most of Asia but will be stronger over West Asia and western South Asia. Under the 1.5 ℃ and 2 ℃ warming targets, the probability of very hot weather (anomalies greater than 1σ, σ is standard deviation), extremely hot weather (anomalies greater than 3or), and extremely heavy precipitation (anomalies greater than 3σ) occurring will increase by at least once, 10%, and 10%, respectively, compared to the reference period (1861-1900).
文摘Change related to climate in Macao was studied on the basis of daily temperature observations over the period 1901-2007. The result shows that annual mean surface air temperature in Macao as a whole rose with a warming rate of about 0.066℃ per 10 years in the recent 107 years. The most evident warming occurred in spring and winter. The interdecadal variations of the seasonal mean temperature in summer and winter appeared as a series of waves with a time scale of about 30 years and 60 years, respectively. The annual mean minimum temperature increased about twice as fast as the annual mean maximum temperature, resulting in a broad decline in the annual mean diurnal range. The interdecadal variations of annual mean maximum temperature are obviously different from those of annual mean minimum temperature. It appears that the increase in the annual mean maximum temperature in the recent 20 years may be part of slow climate fluctuations with a periodicity of about 60 years, whereas that in the annual mean minimum temperature appears to be the continuation of a long-term warming trend.
基金the National Basic Research Program of China(973 Program)(No. 2010CB428401)the Special Fund of Climate Change of the China Meteorological Administration (CCSF-09-16)by the National Natural Science Foundation of China(40910177)
文摘Monthly temperature and precipitation time-series for the Zhujiang River Basin are analyzed in order to identify changes in climate extremes. Daily temperature and precipitation data from 1961 to 2007 of 192 meteorological stations are used. Two temperature indicators (monthly mean and monthly maximum mean) and three precipitation indicators (monthly total, monthly maximum consecutive 5-day precipitation, and monthly dry days) are analyzed. Tendencies in all five indicators can be observed. Many stations show significant positive trends (above the 90% confidence level) for monthly mean temperatures and monthly maximum mean temperatures. For all months, a significant increase in temperature from 1961 to 2007 can be observed in the entire basin with the coastal area in particular. Positive trends of precipitation extremes can be observed from January to March. Negative trends are detected from September to November. The number of dry days in October increased significantly at 40% of all meteorological stations. Stations with changes of monthly precipitation extremes are scattered over the Zhujiang River Basin. An aggregation of heat waves and droughts can be detected which is accompanied by significant increases of temperature extremes and the negative tendencies in precipitation extremes. The detection of tendencies in climate station density. extremes essentially relies on a good data quality and high
基金sponsored by the National Key R&D Programof China(grant number 2016YFA0600404)Key Technology of Integration of Meteorological and Application Projects(grant number CMAGJ2015Z16)+1 种基金the Youth Innovation Promotion Association of CAS(grant number 2016075)the Jiangsu Collaborative Innovation Center for Climate Change
文摘On 1 April 2017 China established Xiongan New Area in Hebei Province, which was described as ‘a strategy crucial for a millennium to come'. A point of interest for the public is to be aware of the historical climate change in this new area; however, results from previous global-scale or largerregional-scale averages provide relatively limited information because of the distinct regional differences in climate change. This study analyzes the changes in mean and extreme temperature in this area, based on homogenized daily temperature data for the period 1960–2016. The results show a significant warming in the indices of annual, summer, and winter mean temperature(Tmean), maximum temperature(Tmax), and minimum temperature(Tmin). The linear rate of annual Tmean is 0.34 °C/decade. Temperatures on the hottest day, the warmest night, the coldest day, and the coldest night, every year, all show increasing trends, with the trends in the two nighttime-related indices being significant. An increasing occurrence of warm days, warm nights, hot days, and tropical nights, but a decreasing occurrence of cold days, cold nights, icing days, and frost days, are found, all of which are significant, except for the occurrences of hot days and icing days. A significant extension of the length of the thermal growing season is also found. The magnitudes of change in most of the temperature indices in Xiongan New Area are larger than those of the adjacent Jing-Jin-Ji and North China regional mean. These results could provide valuable information for policymakers, city planners, engineers, and migrants to this new area.
基金supported by the Climate Change Special Project of China Meteorological Administration:The Assessment Report Preparation of the Climate Change of Central China (No. CCSF-10-04)
文摘Based on the observations from 239 meteorological stations located in Central China (Henan, Hubei and Hunan provinces), this paper focuses on the climate change facts during 1961- 2010. There was a significant increasing trend in annual mean temperature for Central China during 1961 -2010. The increasing rate was 0.15℃ per decade, which was lower than the national trend. Since the mid-1980s, temperature increasing was obvious. Large increasing rate was observed in the mid-eastern part of Central China. For the four seasons, the increasing rate in winter was the largest (0.27℃ per decade). The increasing rate in the annual mean minimum temperature was larger than that in the annual mean maximum temperature from 1961 to 2010. As a result, the diurnal range of temperature decreased at the rate of -0.10℃ per decade. The extreme high temperature events were increasing while the extreme low temperature events were significantly decreasing. There was no obvious trend in annual precipitation for Central China during 1961-2010. Precipitation in summer and winter significantly increased; change of precipitation in spring was not obvious; precipitation in autumn was decreasing. The decreasing rate of annual rainy days was -3.4 d per decade. The precipitation intensity increased at the rate of 0.25 mm d-1 per decade. Heavy-rain days significantly increased. Spring and summer started earlier while autumn and winter started later. As a result, spring and summer duration was expanding whereas autumn and winter duration shortened.
基金supported by China Meteorological Administration (CMA) Specific Research on ClimateChange (No. CCSF-10-06)the National Key Scientific Research Program of Global Change (No. 2010CB951001)
文摘By using the observation data from 89 weather stations in Xinjiang during 1961-2010, this paper analyzed the basic climatic elements including temperature, precipitation, wind speed, sunshine duration, water vapor pressure, and dust storm in the entire Xinjiang and the subareas: North Xinjiang, Tianshan Mountains, and South Xinjiang. The results indicate that from 1961 to 2010 the annual and seasonal mean temperatures in the entire Xinjiang show an increasing trend with the increasing rate rising from south to north. The increasing rate of annual mean minimum temperature is over twice more than that of the annual mean maximum temperature, contributing much to the increase in the annual averages. The magnitude of the decrease rate of low-temperature days is larger than the increase rate of high-temperature days. The increase of warm days and warm nights and the decrease of cold days and cold nights further reveal that the temperature increasing in Xinjiang is higher. In addition, annual and seasonal rainfalls have been increasing. South Xinjiang experiences higher increase in rainfall amounts than North Xinjiang and Tianshan Mountains. Annual rainy days, longest consecutive rainy days, the daily maximum precipitation and extreme precipitation events, annual torrential rain days and amount, annual blizzard days and amount, all show an increasing trend, corresponding to the increasing in annual mean water vapor pressure. This result shows that the humidity has increased with temperature increasing in the past 50 years. The decrease in annual mean wind speed and gale days lessen the impact of dust storm, sandstorm, and floating dust events. The increase in annual rainy days is the cause of the decrease in annual sunshine duration, while the increase in spring sunshine duration corresponds with the decrease in dust weather. Therefore, the increase in precipitation indicators, the decrease in gales and dust weather, and the increasing in sunshine duration in spring will be beneficial to crops growth.
基金Project(2006BAJ01A05) supported by National Science and Technology Pillar Program during the 11th Five-year Plan Period of China
文摘To explore the energy saving effect of building envelope, the experiments were carried out through a comparison of basic cubicle in summer. Experiments show that if energy efficiency measures are applied only in the external walls and windows, the energy saving cubicles have an average energy efficiency ratio of 27.75% and 27.05% when the air change rates are 1.1 and 1.4 h-1 in summer, with both values being over the standard target value by 25%. And the indoor air temperature of the energy saving cubicle is below that of the basic cubicle. The daily mean temperature difference between the interior surface of insulation wall and no insulation reaches 1.47℃, and the mean temperature difference is up to 8.52℃ between the interior surface and exterior surface of insulating glass and single glass. The two cubicles were simulated for energy consumption using VisualDOE4.0 software under real weather conditions in summer. The results show that the mean deviation is 10.02% between experimental and simulated energy efficiency ratio. The correctness and validity of simulation results of the VisualDOE4.0 software are proved.
基金supported by the Special Project on Climate Change in China Meteorological Administation(No. CCSF2010-5)
文摘In this study, observational data from 141 meteorological stations in Northwest China, including temperature, precipitation, dust storm, gale days and wind speed, were analyzed statistically to gain insight of the features of basic climate index and extreme climate events. The results showed that the annual mean temperature and seasonal mean temperature rose significantly, and the rising rate of the annual mean temperature is 0.27℃ per decade; the extreme high temperature days have increased; the interdecadal change of annual precipitation is marked, and the precipitation in winter and summer increased slightly, while decreased slightly in spring and autumn. The annual precipitation increased in the area west of the Yellow River, whereas decreased in the area east of the river. The drought had an increasing trend. There were 17 droughts during 1961-2010, and 10 droughts from 1991 to 2010. The number of droughts in spring and autumn increased, while decreased in summer.
文摘The world is facing a big challenge of climatic change, mainly due to increasing concentrations of GHGs (greenhouse gases) in the atmosphere. Many researches indicated that the climate change occurred disproportionately on developing countries such as MENA (Middle East and North Africa) countries. The climatic model CGCM3.1 (T47) 2 is used in this research to explain the changes in average temperatures and the rainfall on the MENA region with special emphases on Iraq. Historical records (1900-2009) and future (2020-2099) were studied and compared; each period was divided to four sub-periods of thirty years. The results showed that the average monthly temperature for the four historical periods fluctuated between the lowest and highest value as follows: 9.2-32.9, 10.3-32.7, 9.3-32.8 and 8.6-33.9 (℃). The rainfall for historical periods kept on the same distribution during the past 109 years, and fluctuated between the lowest and highest value of 21.3 mm and 37.6 mm with an average that reached up to 26.51 mm. For the future period, the maximum average monthly temperature reached up to 37.41 (℃) during June and minimum average monthly temperature reached up to 4.24 (℃) during January. The average monthly temperature fluctuated giving a clear impression that the future portends a higher temperature. The average monthly rainfall, for the future period, fluctuated between the lowest and highest value of 12.91 mm and 20.63 mm with an average that reached 16.84 mm which represent a reduction percentage of about 36.47% relative to the historical record of rainfall for the sanae months.
文摘The observed global mean temperature is the highest on record for the past decade but has plateaued to form an apparent"hiatus"in global temperature rise,with an almost zero short-term trend. Several speakers presented results on the hiatus and suggested possible mechanisms.
基金supported by National asic Research Program of China (Grant Nos. 013CBA01806)National Natural Sciences oundation of China (Grant Nos. 91025011, 1222001)
文摘The results from three methods aimed at improving precipitation type (e.g., rain, sleet, and snow) estimation are presented and compared in this paper. The methods include the threshold air temperature (AT), threshold wet bulb temperature (WBT) and Koistinen and Saltikoff (KSS) methods. Dot graphs are plotted to acquire the threshold air temperature or the threshold wet bulb temperature using daily averaged air temperature, wet bulb temperature and precipitation data at 643 stations from 1961 to 1979 (precipitation types are not labeled in the database from 1980 to present) in China. The results indicate that the threshold AT or WBT methods are not able to differentiate rain, sleet and snow in the most regions in China; sleet is difficult to differentiate from other precipitation types based on the two threshold methods. Therefore, one threshold AT and WBT method was used in this study to differentiate rain and snow. Based on Gaussian- Kriging interpolation of threshold air temperature (To) and wet bulb temperature (Tw), the To and Tw contour lines and contour surfaces are calculated for China. Finally, a comparison between the KSS, AT and WBT methods are provided in which the KSS method is calculated based on air temperature and relative humidity. The results suggest that the KSS method is more appropriate for water phase estimation than are the other methods; the maximum precision for rain and snow is 99% and 94%, respectively. The AT method performs better than the WBT method when the critical air temperature is 2℃.
基金supported by the Special Climate Change Research Program of China Meteorological Administration (No. CCSF-09-11, CCSF-09-03, CCSF2011-25, and CCSF201211)the Science and Technology Planning Project of Guangdong province (No.2011A030200021)
文摘Daily climate data at 110 stations during 1961-2010 were selected to examine the changing characteristics of climate factors and extreme climate events in South China. The annual mean surface air temperature has increased significantly by 0.16℃ per decade, most notably in the Pearl River Delta and in winter. The increase rate of the annual extreme minimum temperature (0.48℃ per decade) is over twice that of the annual extreme maximum temperature (0.20℃ per decade), and the increase of the mean temperature is mainly the result of the increase of the extreme minimum temperature. The increase rate of high-temperature days (1.1 d per decade) is close to the decrease rate of low-temperature days (-1.3 d per decade). The rainfall has not shown any significant trend, but the number of rainy days has decreased and the rain intensity has increased. The regional mean sunshine duration has a significant decreasing trend of -40.9 h per decade, and the number of hazy days has a significant increasing trend of 6.3 d per decade. The decrease of sunshine duration is mainly caused by the increase of total cloud, not by the increase of hazy days in South China. Both the regional mean pan evaporation and mean wind speed have significant decreasing trends of -65.9 mm per decade and -0.11 m s-1 per decade, respectively. The decrease of both sunshine duration and mean wind speed plays an important role in the decrease of pan evaporation. The number of landing tropical cyclones has an insignificant decreasing trend of -0.6 per decade, but their intensities show a weak increasing trend. The formation location of tropical cyclones landing in South China has converged towards 10-19°N, and the landing position has shown a northward trend. The date of the first landfall tropical cyclone postpones 1.8 d per decade, and the date of the last landfall advances 3.6 d per decade, resulting in reduction of the typhoon season by 5.4 d per decade.
基金supported by the National Natural Science Foundation of China (Grant Nos.40890052 and 41275087)
文摘Using numerical model simulations, global surface temperature is projected to increase by l^C to 4~C during the 21 st century, primarily as a result of increasing concentrations of greenhouse gases. In the present study, a predictive technique incorporating driving forces into an observation time series was used to project the global mean surface temperature under four representative sce- narios of future emissions over the 21st century.
基金supported by Innovation and Research Foundation of Ocean University of China(No.201261009)the National Natural Science Foundation of China(Nos.40930844 and 10735030)the National Basic Research Program of China(the 973 Program)under grant No.2005CB422 301
文摘We studied the impact of sea surface temperature anomaly(SSTA) in the Japan Sea and the sea area east of Japan on the winter rainfall and air temperature in Northeast(NE) China using the singular value decomposition(SVD) and empirical orthogonal function(EOF). The monthly-mean rainfall data observed at 160 stations in China, monthly-mean sea surface temperature(SST) of the Hadley Center for Climate Prediction and Research and monthly-mean air temperature from the NCEP reanalysis during 1960–2011 were used. Correlation analysis indicates that the SSTAs in the Japan Sea in September may last for three or four months and are an important index for forecasting the winter rainfall and air temperature in NE China. Positive SSTAs in the central Japan Sea and in the sea area east of Tokyo correspond to positive rainfall anomaly and negative air temperature anomaly in NE China. With the rise of SST in the Japan Sea, a weak cyclone appears over the Japan Sea. The northeasterly wind transports water vapor from the Okhotsk to NE China, resulting in more rainfall and lower air temperature. Negative SSTA years are accompanied by warmer air temperature and less snow in NE China. The 1000 h Pa geopotential height anomaly and wind anomaly fields are simulated by IAP-9L model, which supports the analysis results.
文摘An experimental investigation was conducted to measure the temperature variation across the flow channel and to determine the performance of a natural convection solar air heater at various tilt angles from 15, 30 and 45°. The results of the temperature profile across the air gap showed that heat transfer from the absorber plate to the air stream was mainly by convection. At a particular section, mean air temperature could be calculated from the arithmetic mean of the temperature profile across the air gap to within ± 2 ℃. The axial air temperature distribution was non linear and did not increase much beyond 1 m of collector length. It tended to decrease towards the end of the collector. Overall glass, absorber plate and mean air temperatures over the entire length of the solar air heater could be determined by averaging the mean axial temperatures to within ± 2 ℃. The heater performed better as inclination increased.
文摘Changes of air temperatures and atmosphere circulation at three high mountainous stations in Bulgaria are investigated for the period of 1941-2008.The three stations are located on peaks Musala,Cherni vrah and Botev,where air temperature data have good quality.Some missing data were recovered using the method of differences. A significant mean annual air temperature rise happened in high mountainous parts of Bulgaria- the warming is in the order of 0.7°C for the entire period.The increase is very prominent particularly in the last 30 years.Main contributors to this overall tendency are summer months-June,July and August.To some degree,January also could be included in this group.November trend shows temperature rise at the beginning of the investigated period.One of the causes for such a tendency is atmosphere circulation in respective months.It also shows signs of considerable reorganization in both winter and summer.There is an increase of the cases of warm atmosphere patterns typical for winter, summer and autumn seasons in Bulgaria.Meridional circulation has essential significance for air temperatures during the cold half of the year.In January and June atmosphere circulation has a substantial influence on the thermal regime of air in high mountains of Bulgaria.In July,August and November this influence is reduced.There are no cycles in air temperatures for the investigated period.
文摘The purpose of this paper is to present a simple way to approximate the dependence of the global mean air temperature at Earth's surface on atmospheric concentration of carbon dioxide. Current discussions include energy aspects of the greenhouse effect and the global warming. The starting point for the research are laws of thermodynamics, energy equilibrium and absorption and emission property of the atmosphere. According to the calculations, the natural and the anthropogenic changes effect the atmosphere. By the year 2100 the CO2 concentration will be doubled in comparison with the value of the pre-industrial ages. The doubled CO2 concentration will mean a temperature change about 1 ℃-1.5 ℃.
基金supported by the National Natural Science Foundation of China (Grant No. 40974086)the National Important Basic Research Project (Grant No. 2011CB811405)
文摘The data observed by a spectral airglow temperature imager (SATI) at Beijing National Observatory of Space Environment from July 23, 2008 to July 3l, 2009 are used to study night mesopause temperature in Beijing. From variations of temperature at 87 and 94 km obtained from OH (6-2) and 02 (0-1) airglow spectra, temperature at night is shown lowest in the summer and highest in the winter. In summer, average temperature at 87 km is 173.9 K, lower than average temperature 180.1 K at 94 km. But in winter, average temperature at 87 Ion is 201.2 K, higher than average temperature 194.8 K at 94 kin. The altitude of mesopause in Beijing is below 87 km in summer and above 94 km in winter. There are about 120-150 days when the mesopause locates below 87 km, which is in agreement with the results of SABER/TIMED. Variations of temperatures at 87 and 94 km are analyzed by harmonic method. Our results show that amplitudes of annual oscillation of temperature at 87 and 94 km are 17.5 and 7.8 K respectively. Amplitudes of semi-annual oscillation at 87 and 94 km are 1.6 and 5.3 K, which are smaller than those of annual oscillation. Although there are differences among different observations because of different locations and different instruments, our results are in general agreement with observation at similar latitude as Beijing.