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Most Cited Advances in Climate Change Research Articles

The most cited articles published since 2013, extracted from Scopus.

Introduction of CMIP5 experiments carried out with the climate system models of Beijing climate center

Volume 4, Issue 1, January 2014, Pages 41-49
Xiao Ge Xin | Tong Wen Wu | Jie Zhang

The climate system models from Beijing Climate Center, BCC_CSM1.1 and BCC_CSM1.1-M, are used to carry out most of the CMIP5 experiments. This study gives a general introduction of these two models, and provides main information on the experiments including the experiment purpose, design, and the external forcings. The transient climate responses to the CO2concentration increase at 1% per year are presented in the simulation of the two models. The BCC_CSM1.1-M result is closer to the CMIP5 multiple models ensemble. The two models perform well in simulating the historical evolution of the surface air temperature, globally and averaged for China. Both models overestimate the global warming and underestimate the warming over China in the 20th century. With higher horizontal resolution, the BCC_CSM1.1-M has a better capability in reproducing the annual evolution of surface air temperature over China.

Progress in research on homogenization of climate data

Volume 3, Issue 2, January 2014, Pages 59-67
Li Juan Cao | Zhong Wei Yan

The observation data from ground surface meteorological stations is an important basis on which climate change research is carried out, while the homogenization of the data is necessary for improving the quality and homogeneity of the time series. This paper reviews recent advances in the techniques of identifying and adjusting in homogeneity in climate series. We briefly introduce the results of applying two commonly accepted and well-developed methods (RHtest and MASH) to surface climate observations such as temperature and wind speed in China. We then summarize current progress and problems in this field, and propose ideas for future studies in China. Along with collecting more detailed metadata, more research on homogenization technology should be done in the future. On the basis of comparing and evaluating advantages and disadvantages of different homogenization methods, the homogenized climate data series of the last hundred years should be rebuilt.

Impacts of regional-scale land use/land cover change on diurnal temperature range

Volume 4, Issue 3, January 2013, Pages 166-172
Wen Jian Hua | Hai Shan Chen

The NCAR Community Atmosphere Model (CAM4.0) was used to investigate the climate effects of land use/land cover change (LUCC). Two simulations, one with potential land cover without significant human intervention and the other with current land use, were conducted. Results show that the impacts of LUCC on diurnal temperature range (DTR) are more significant than on mean surface air temperature. The global average annual DTR change due to LUCC is -0.1°C, which is three times as large as the mean temperature change. LUCC influences regional DTR as simulated by the model. In the mid-latitudes, LUCC leads to a decrease in DTR, which is mainly caused by the reduction in daily maximum temperature. However, there are some differences in the low latitudes. The reduction in DTR in East Asia is mainly the result of the decrease in daily maximum temperature, while in India, the decrease in DTR is due to the increase in daily minimum temperature. In general, the LUCC significantly controls the DTR change through the changes in canopy evaporation and transpiration.

Trends of extreme flood events in the Pearl River Basin during 1951-2010

Volume 4, Issue 2, January 2013, Pages 110-116
Zhi Yong Wu | Zhi Yong Wu | Gui Hua Lu | Gui Hua Lu | Zhi Yu Liu | Jin Xing Wang | Heng Xiao

The study investigated the trend of extreme flood events in the Pearl River basin during 1951-2010. Stream flow data at 23 gauging stations were used for the study. The Pearson type III distribution was selected for the flood frequency analysis. Results indicate that extreme flood events increase significantly in the Pearl River Basin since 1980. At the 23 gauging stations, there are 16 (70%) stations show positive (increasing) trends in 1981-2010. Most of the 16 stations are located along the West River and North River. While 7 (30%) stations show negative (decreasing) trends, and are found in the East River and the southeast region of the West River Basin.

Estimation of methane emissions from municipal solid waste landfills in China based on point emission sources

Volume 5, Issue 2, January 2014, Pages 81-91
Bo Feng Cai | Jian Guo Liu | Qing Xian Gao | Xiao Qin Nie | Dong Cao | Lan Cui Liu | Ying Zhou | Zhan Sheng Zhang

The methane (CH4) emissions from municipal solid waste (MSW) landfills in China in 2007 were estimated based on database of the three-dimensional emission factors matrix and point sources, by an IPCC recommended FOD (first-order decay) model. The location, capacity and age of landfills constitute the three dimensions of the emission factors matrix, which were obtained by laboratory analysis and in situ investigation. Key parameters such as waste composition, degradable organic carbon ratio, CH4correction factor, oxidation factor and recovery rate, were carefully analyzed in terms of these three dimensions. The point sources database consists of 2,107 MSW landfills in cities and towns of China in 2007. The results show that the CH4 emissions from MSW landfills were 1.186 Mt in 2007. Compared with the CH4emissions of 2.20 Mt in 2005, the significant discrepancy mainly comes from statistical data of landfills, e.g., number of landfills and amount of waste disposed in landfills. CH4emissions were lower than 700 t for most of the landfills, whereas there were 279 landfills with emissions larger than 1,000 t, and only 10 landfills with emissions larger than 10,000 t. Jiangsu province ranks the largest emitter with 98,700 t while Tibet is the smallest emitter with 2,100 t. In general, the emissions from eastern provinces, such as Jiangsu, Guangdong and Zhejiang, were larger than those from western provinces, such as Ningxia, Tibet and Qinghai.

Surface air temperature simulations over China with CMIP5 and CMIP3

Volume 4, Issue 3, January 2013, Pages 145-152
Yan Guo | Wen Jie Dong | Fu Min Ren | Zong Ci Zhao | Jian Bin Huang

Historical simulations of annual mean surface air temperature over China with 25 CMIP5 models were assessed. The observational data from CRUT3v and CN05 were used and further compared with historical simulations of CMIP3. The results show that CMIP5 models were able to simulate the observed warming over China from 1906 to 2005 (0.84°C per 100 years) with a warming rate of 0.77°C per 100 years based on the multi-model ensemble (MME). The simulations of surface air temperature in the late 20th century were much better than those in the early 20th century, when only two models could reproduce the extreme warming in the 1940s. The simulations for the spatial distribution of the 20-year-mean (1986-2005) surface air temperature over China fit relatively well with the observations. However, underestimations in surface air temperature climatology were still found almost all over China, and the largest cold bias and simulation uncertainty were found in western China. On sub-regional scale, northern China experienced stronger warming than southern China during 1961-1999, for which the CMIP5 MME provided better simulations. With CMIP5 the difference of warming trends in northern and southern China was underestimated. In general, the CMIP5 simulations are obviously improved in comparison with the CMIP3 simulations in terms of the variation in regional mean surface air temperature, the spatial distribution of surface air temperature climatology and the linear trends in surface air temperature all over China.

Modeling an emissions peak in China around 2030: Synergies or trade-offs between economy, energy and climate security

Volume 5, Issue 4, January 2014, Pages 169-180
Qi Min Chai | Qi Min Chai | Hua Qing Xu

© 2015 The Authors. China has achieved a political consensus around the need to transform the path of economic growth toward one that lowers carbon intensity and ultimately leads to reductions in carbon emissions, but there remain different views on pathways that could achieve such a transformation. The essential question is whether radical or incremental reforms are required in the coming decades. This study explores relevant pathways in China beyond 2020, particularly modeling the major target choices of carbon emission peaking in China around 2030 as China-US Joint Announcement by an integrated assessment model for climate change IAMC based on carbon factor theory. Here scenarios DGS-2020, LGS2025, LBS-2030 and DBS-2040 derived from the historical pathways of developed countries are developed to access the comprehensive impacts on the economy, energy and climate security for the greener development in China. The findings suggest that the period of 2025-2030 is the window of opportunity to achieve a peak in carbon emissions at a level below 12 Gt CO2 and 8.5 t per capita by reasonable trade-offs from economy growth, annually -0.2% in average and cumulatively -3% deviation to BAU in 2030. The oil and natural gas import dependence will exceed 70% and 45% respectively while the non-fossil energy and electricity share will rise to above 20% and 45%. Meantime, the electrification level in end use sectors will increase substantially and the electricity energy ratio approaching 50%, the labor and capital productivity should be double in improvements and the carbon intensity drop by 65% by 2030 compared to the 2005 level, and the cumulative emission reductions are estimated to be more than 20 Gt CO2 in 2015-2030.

PM2.5 and tropospheric O3in China and an analysis of the impact of pollutant emission control

Volume 5, Issue 3, January 2014, Pages 136-141
Hua Zhang | Bing Xie | Bing Xie | Shu Yun Zhao | Shu Yun Zhao | Qi Chen | Qi Chen

Copyright © 2014, National Climate Center (China Meteorological Administration). Production and hosting by Elsevier B.V. on behalf of KeAi. This study reviewed the status of PM2.5 and tropospheric O3observations in China (15-55°N, 72-136°E). Initially, the distribution of tropospheric O3over the globe and China was determined based on satellite observations made during 2010-2013. The annual mean values were 29.78 DU and 33.97 DU over the globe and China, respectively. The distribution of PM2.5 and seasonal changes in concentrations in China were then simulated using an aerosol chemistry-climate coupled model system, with an annual mean value of 0.51 × 10-8kg m-3. The contributions from five different aerosols to the simulated PM2.5 concentrations in different seasons were also determined. The relationships among the emissions of aerosols, greenhouse gases and their precursors and radiative forcings were determined with reference to the (IPCC AR5) Intergovernmental Panel on Climate Change the Fifth Assessment Report. From these relationships, the possible effects of controlling O3precursors and (PM) particulate matter on the climate were considered. The influence of the control of O3precursors was not totally clear, and reducing emissions of short-lived greenhouse gases and black carbon was considered a secondary measure for short-term (the next 50 years) climate-change mitigation. Reducing emissions of CO2is still the best strategy for meeting the target of a global average rise in surface air temperature of less than 2 °C. Near- and short-term emission reduction strategies are important for both effective environmental protection and climate-change mitigation.

Method for calculating CO2emissions from the power sector at the provincial level in China

Volume 5, Issue 2, January 2014, Pages 92-99
Cui Mei Ma | Quan Sheng Ge

Based on the detailed origins of each province's electricity consumption, a new method for calculating CO2emissions from the power sector at the provincial level in China is proposed. With this so-called consumer responsibility method, the emissions embodied in imported electricity are calculated with source-specific emission factors. Using the new method, we estimate CO2emissions in 2005 and 2010. Compared with those derived from the producer responsibility method, the power exporters' emissions decreased sharply. The emissions from the power sector in Inner Mongolia, the largest power exporter of China, decreased by 109 Mt in 2010. The value is equivalent to those from Shaanxi's power production and Canada's power and heat production. In contrast, the importers' emissions increased substantially. The emissions from the power sector in Hebei, the largest power importer of China, increased by 74 Mt. Emissions of Beijing, increased by 60 Mt (320%), in 2010. Thus, we suggest that the Chinese government should take the emissions, as calculated from the consumption perspective, into account when formulating and assessing local CO2emission reduction targets.

Earth observation big data for climate change research

Volume 6, Issue 2, January 2015, Pages 108-117
Hua Dong Guo | Hua Dong Guo | Li Zhang | Li Zhang | Lan Wei Zhu | Lan Wei Zhu

© 2015 National Climate Center (China Meteorological Administration). Production and hosting by Elsevier B.V. Earth observation technology has provided highly useful information in global climate change research over the past few decades and greatly promoted its development, especially through providing biological, physical, and chemical parameters on a global scale. Earth observation data has the 4V features (volume, variety, veracity, and velocity) of big data that are suitable for climate change research. Moreover, the large amount of data available from scientific satellites plays an important role. This study reviews the advances of climate change studies based on Earth observation big data and provides examples of case studies that utilize Earth observation big data in climate change research, such as synchronous satellite-aerial-ground observation experiments, which provide extremely large and abundant datasets; Earth observational sensitive factors (e.g., glaciers, lakes, vegetation, radiation, and urbanization); and global environmental change information and simulation systems. With the era of global environment change dawning, Earth observation big data will underpin the Future Earth program with a huge volume of various types of data and will play an important role in academia and decisionmaking. Inevitably, Earth observation big data will encounter opportunities and challenges brought about by global climate change.

Estimate of China's energy carbon emissions peak and analysis on electric power carbon emissions

Volume 5, Issue 4, January 2014, Pages 181-188
Zhi Xuan Wang | Jing Jie Zhang | Li Pan | Fan Yang | Li Na Shi

© 2015 The Authors. China's energy carbon emissions are projected to peak in 2030 with approximately 110% of its 2020 level under the following conditions: 1) China's gross primary energy consumption is 5 Gtce in 2020 and 6 Gtce in 2030; 2) coal's share of the energy consumption is 61% in 2020 and 55% in 2030; 3) non-fossil energy's share increases from 15% in 2020 to 20% in 2030; 4) through 2030, China's GDP grows at an average annual rate of 6%; 5) the annual energy consumption elasticity coefficient is 0.30 in average; and 6) the annual growth rate of energy consumption steadily reduces to within 1%. China's electricity generating capacity would be 1,990 GW, with 8,600 TW h of power generation output in 2020. Of that output 66% would be from coal, 5% from gas, and 29% from non-fossil energy. By 2030, electricity generating capacity would reach 3,170 GW with 11,900 TW h of power generation output. Of that output, 56% would be from coal, 6% from gas, and 37% from non-fossil energy. From 2020 to 2030, CO2 emissions from electric power would relatively fall by 0.2 Gt due to lower coal consumption, and relatively fall by nearly 0.3 Gt with the installation of more coal-fired cogeneration units. During 2020-2030, the portion of carbon emissions from electric power in China's energy consumption is projected to increase by 3.4 percentage points. Although the carbon emissions from electric power would keep increasing to 118% of the 2020 level in 2030, the electric power industry would continue to play a decisive role in achieving the goal of increase in non-fossil energy use. This study proposes countermeasures and recommendations to control carbon emissions peak, including energy system optimization, green-coal-fired electricity generation, and demand side management.

An analysis of China's CO<inf>2</inf> emission peaking target and pathways

Volume 5, Issue 4, January 2014, Pages 155-161
Jian Kun He

© 2015 The Author. China has set the goal for its CO2 emissions to peak around 2030, which is not only a strategic decision coordinating domestic sustainable development and global climate change mitigation but also an overarching target and a key point of action for China's resource conservation, environmental protection, shift in economic development patterns, and CO2 emission reduction to avoid climate change. The development stage where China maps out the CO2 emission peak target is earlier than that of the developed countries. It is a necessity that the non-fossil energy supplies be able to meet all the increased energy demand for achieving CO2 emission peaking. Given that China's potential GDP annual increasing rate will be more than 4%, and China's total energy demand will continue to increase by approximately 1.0%-1.5% annually around 2030, new and renewable energies will need to increase by 6%-8% annually to meet the desired CO2 emission peak. The share of new and renewable energies in China's total primary energy supply will be approximately 20% by 2030. At that time, the energy consumption elasticity will decrease to around 0.3, and the annual decrease in the rate of CO2 intensity will also be higher than 4% to ensure the sustained growth of GDP. To achieve the CO2 emission peaking target and substantially promote the low-carbon development transformation, China needs to actively promote an energy production and consumption revolution, the innovation of advanced energy technologies, the reform of the energy regulatory system and pricing mechanism, and especially the construction of a national carbon emission cap and trade system.

Analysis of China's haze days in the winter half-year and the climatic background during 1961-2012

Volume 5, Issue 1, January 2014, Pages 1-6
Lian Chun Song | Lian Chun Song | Rong Gao | Rong Gao | Ying Li | Ying Li | Guo Fu Wang | Guo Fu Wang

The characteristics of haze days and the climatic background are analyzed by using daily observations of haze, precipitation, mean and maximum wind speed of 664 meteorological stations for the period of 1961-2012. The results show that haze days occur significantly more often in eastern China than in western China. The annual number of haze days is 5-30 d in most parts of central-eastern China, with some areas experiencing more than 30 d, while less than 5 d are averagely occurring in western China. Haze days are mainly concentrated in the winter half-year, with most in winter, followed by autumn, spring, and then summer. Nearly 20% of annual haze days are experienced in December. The haze days in central-eastern China in the winter half-year have a significant increasing trend of 1.7 d per decade during 1961-2012. There were great increases in haze days in the 1960s, 1970s and the beginning of the 21st century. There was also significant abrupt changes of haze days in the early 1970s and 2000s. From 1961 to 2012, haze days in the winter half-year increased in South China, the middle-lower reaches of the Yangtze River, and North China, but decreased in Northeast China, eastern Northwest China and eastern Southwest China. The number of persistent haze is rising. The Longer the haze, the greater the proportion to the number persistent haze. Certain climatic conditions exacerbated the occurrence of haze. The correlation coe±cient between haze days and precipitation days in the winter half-year is mainly negative in central-eastern China. The precipitation days show a decreasing trend in most parts of China, with a rate of around -4.0 d per decade in central-eastern China, which reduces the sedimentation capacity of atmospheric pollutants. During the period of 1961-2012, the correlation coe±cients between haze days and mean wind speed and strong wind days are mainly negative in central-eastern China, while there exists positive correlation between haze days and breeze days in the winter half-year. The mean wind speed and strong wind days are decreasing, while breeze days are increasing in most parts of China, which is benefitial to the reduction of the pollutants di®usion capacity. As a result, haze occurs more easily.

Influences of urban temperature on the electricity consumption of Shanghai

Volume 5, Issue 2, January 2014, Pages 74-80
Yi Ling Hou | Yi Ling Hou | Hai Zhen Mu | Guang Tao Dong | Jun Shi

By using data of daily electricity consumption and temperature for the period 2003-2007 in Shanghai, the variation of energy consumption and the correlations between energy consumption and temperature are analyzed. The results indicate that winter and summer are the two peak seasons of energy consumption due to the urban residential heating and cooling demand. The base temperature of electricity and daily temperature is 10° C in winter and 22° C in summer respectively. When the outdoor temperature is below 10° C, the heating demand becomes obvious, and with over 22° C the cooling demand. The spatial distribution of cooling degree-days (CDD) and heating degree-days (HDD) clearly shows urbanization effects. By the influence of urbanization the central city experiences greater CDD in summer and lower HDD in winter. The projected temperature for 2011-2050 implies a significant increase in CDD and a decrease in HDD. This may have implications on the future energy demand if the current energy consumption pattern does not change.

Natural and human-induced changes in summer climate over the East Asian monsoon region in the last half century: A review

Volume 6, Issue 2, January 2015, Pages 131-140
Ren He Zhang

© 2015 National Climate Center (China Meteorological Administration). Production and hosting by Elsevier B.V. In the last half century, a significant warming trend occurred in summer over eastern China in the East Asian monsoon region. However, there were no consistent trends with respect to the intensity of the East Asian summer monsoon (EASM) or the amount of summer rainfall averaged over eastern China. Both of the EASM and summer rainfall exhibited clear decadal variations. Obvious decadal shifts of EASM occurred around the mid- and late 1970s, the late 1980s and the early 1990s, and the late 1990s and early 2000s, respectively. Summer rainfall over eastern China exhibited a change in spatial distribution in the decadal timescale, in response to the decadal shifts of EASM. From the mid- and late 1970s to the late 1980s and the early 1990s, there was a meridional tri-polar rainfall distribution anomaly with more rainfall over the Yangtze River valley and less rainfall in North and South China; but in the period from the early 1990s to the late 1990s and the early 2000s the tri-polar distribution changed to a dipolar one, with more rainfall appearing over southern China south to the Yangtze River valley and less rainfall in North China. However, from the early 2000s to the late 2000s, the Yangtze River valley received less rainfall. The decadal changes in EASM and summer rainfall over eastern China in the last half century are closely related to natural internal forcing factors such as Eurasian snow cover, Arctic sea ice, sea surface temperatures in tropical Pacific and Indian Ocean, ocean-atmospheric coupled systems of the Pacific Decadal Oscillation (PDO) and Asian-Pacific Oscillation (APO), and uneven thermal forcing over the Asian continent. Up to now, the roles of anthropogenic factors, such as greenhouse gases, aerosols, and land usage/cover changes, on existing decadal variations of EASM and summer rainfall in this region remain uncertain.

A simulation study on climatic effects of land cover change in China

Volume 4, Issue 2, January 2013, Pages 117-126
Yan Yu | Yan Yu | Zheng Hui Xie

The regional climate model RegCM4 was used to investigate the regional climate effects of land cover change over China. Two 24-year simulations (1978-2001), one with the land cover derived from the MODIS data and the other with the CLCV (Chinese land cover derived from vegetation map) data, were conducted for a region encompassing China. The differences between the MODIS and CLCV data reflect characteristics of desertification and degradation of vegetation in China. Results indicate that the land cover change has important impacts on local climate through mechanisms related to changes in surface energy, water budgets and macro-scale circulation. In summer, the land cover change leads to a decrease in surface air temperature over southern China, a reduction in precipitation and an increase in surface air temperature in the transitional climate zone and the northern Tibetan Plateau, and an increase in inter-annual variability of surface air temperature in the marginal monsoon zone and northwestern China. Strengthened southwesterly winds increase precipitation to some extent in central and eastern Inner Mongolia by enhancing water vapor transport. In winter, enhanced northerly winds, bringing more dry and cold air, lead to a reduction in precipitation and temperature over areas south of the Yellow River.

Changes in climatic factors and extreme climate events in Northeast China during 1961-2010

Volume 4, Issue 2, January 2013, Pages 92-102
Chun Yu Zhao | Ying Wang | Xiao Yu Zhou | Yan Cui | Yu Lian Liu | Da Ming Shi | Hong Min Yu | Yu Ying Liu

This study focuses on examining the characteristics of climate factors and extreme climate events in Northeast China during 1961-2010 by using daily data from 104 stations, including surface air temperature, precipitation, wind speed, sunshine duration, and snow depth. Results show that annual mean temperature increased at a significant rate of 0.35°C per decade, most notably in the Lesser Khingan Mountains and in winter. Annual rainfall had no obvious linear trend, while rainy days had a significant decreasing trend. So, the rain intensity increased. High-temperature days had a weak increasing trend, and low-temperature days and cold wave showed significant decreasing trends with rates of -3.9 d per decade and -0.64 times per decade, respectively. Frequency and spatial scope of low-temperature hazard reduced significantly. Warm days and warm nights significantly increased at 1.0 and 2.4 d per decade, while cold days and cold nights decreased significantly at -1.8 and -4.1 d per decade, respectively. The nighttime warming rate was much higher than that for daytime, indicating that nighttime warming had a greater contribution to the overall warming trend than daytime warming. The annual mean wind speed, gale days, and sunshine duration had significant decreasing trends at rates of -0.21 m s-1per decade, -4.0 d per decade and -43.3 h per decade, respectively. The snow cover onset dates postponed at a rate of 1.2 d per decade, and the snow cover end date advanced at 1.5 d per decade, which leads to shorter snow cover duration by -2.7 d per decade. Meanwhile, the maximum snow depth decreased at -0.52 cm per decade. In addition, the snow cover duration shows a higher correlation with precipitation than with temperature, which suggests that precipitation plays a more important role in maintaining snow cover duration than temperature.

The economic impact of emission peaking control policies and China's sustainable development

Volume 5, Issue 4, January 2014, Pages 162-168
Yi Wang | Le Le Zou

© 2015 National Climate Center (China Meteorological Administration). To achieve the goals of national sustainable development, the peaking control of CO2 emissions is pivotal, as well as other pollutants. In this paper, we build a Chinese inter-regional CGE model and simulate 13 policies and their combinations. By analyzing the energy consumptions, coal consumptions, relating emissions and their impacts on GDP, we found that with the structure adjustment policy, the proportion of coal in primary fossil fuels in 2030 will decrease from 53% to 48% and CO2 emissions will decrease by 11.3%-22.8% compared to the baseline scenario. With the energy intensity reduction policy, CO2 emissions will decrease by 33.3% in 2030 and 47.8% in 2050 than baseline scenario. Other pollutants will also be controlled as synergetic effects. In this study we also find that although the earlier the peaking time the better for emission amounts control, the economic costs can not be ignored. The GDP will decrease by 2.96%-8.23% under different scenarios. Therefore, integrated policy solutions are needed for realizing the peaks package and more targeted measures are required to achieve the peaks of other pollutants earlier.

Observed climate changes in Southwest China during 1961-2010

Volume 4, Issue 1, January 2014, Pages 30-40
Zhen Feng Ma | Jia Liu | Shun Qian Zhang | Wen Xiu Chen | Shu Qun Yang

The present study focused on statistical analysis of interannual, interdecadal variations of climate variables and extreme climate events during the period of 1961-2010 using observational data from 376 meteorological stations uniformly distributed across Southwest China, which includes Yunnan, Guizhou, Chongqing, Sichuan and Tibet. It was found that temperatures in most of the region were warming and this was especially evident for areas at high elevation. The warming was mostly attributable to the increase in annual mean minimum temperature. The characteristics of high temperature/heat waves are increase in frequency, prolonged duration, and weakened intensity. Annual precipitation showed a weak decreasing trend and drier in the east and more rainfall in the west. The precipitation amount in flood season was declining markedly in the whole region; rainfall from extreme heavy precipitation did not change much, and the portion of annual precipitation contributed by extreme heavy precipitation had an increasing trend; annual non-rainy days and the longest consecutive non-rainy days were both increasing; the extreme drought had a decreasing trend since the 1990s; the autumn-rain days displayed a downward fluctuation with apparent periodicity and intermittency. The number of southwestern vortices was decreasing whereas the number of moving vortices increased.

Probability distribution and projected trends of daily precipitation in China

Volume 4, Issue 3, January 2013, Pages 153-159
Li Ge Cao | Jun Zhong | Jun Zhong | Bu Da Su | Jian Qing Zhai | Macro Gemmer

Based on observed daily precipitation data of 540 stations and 3,839 gridded data from the high-resolution regional climate model COSMO-Climate Limited-area Modeling (CCLM) for 1961-2000, the simulation ability of CCLM on daily precipitation in China is examined, and the variation of daily precipitation distribution pattern is revealed. By applying the probability distribution and extreme value theory to the projected daily precipitation (2011-2050) under SRES A1B scenario with CCLM, trends of daily precipitation series and daily precipitation extremes are analyzed. Results show that except for the western Qinghai-Tibetan Plateau and South China, distribution patterns of the kurtosis and skewness calculated from the simulated and observed series are consistent with each other; their spatial correlation coefficients are above 0.75. The CCLM can well capture the distribution characteristics of daily precipitation over China. It is projected that in some parts of the Jianghuai region, central-eastern Northeast China and Inner Mongolia, the kurtosis and skewness will increase significantly, and precipitation extremes will increase during 2011-2050. The projected increase of maximum daily rainfall and longest non-precipitation period during flood season in the aforementioned regions, also show increasing trends of droughts and floods in the next 40 years.

Influence of urbanization on the thermal environment of meteorological station: Satellite-observed evidence

Volume 6, Issue 1, January 2015, Pages 7-15
Tao Shi | Tao Shi | Yong Huang | Hong Wang | Chun E. Shi | Yuan Jian Yang

© 2015 National Climate Center (China Meteorological Administration). In this paper, five national meteorological stations in Anhui province are taken as typical examples to explore the effects of local urbanization on their thermal environment by using Landsat data from 1990 to 2010. Satellite-based land use/land cover (LULC), land surface temperature (LST), normalized difference vegetation index (NDVI) are used to investigate the effects. The study shows that LULC around meteorological stations changed significantly due to urban expansion. Fast urbanization is the main factor that affects the spatial-temporal distribution of thermal environment around meteorological stations. Moreover, the normalized LST and NDVI exhibit strong inverse correlations around meteorological stations, so the variability of LST can be monitored through evaluating the variability of NDVI. In addition, station-relocation plays an important role in improving representativeness of thermal environment. Notably, the environment representativeness was improved, but when using the data from the station to study climate change, the relocation-induced inhomogeneous data should be considered and adjusted. Consequently, controlling the scale and layout of the urban buildings and constructions around meteorological stations is an effective method to ameliorate observational thermal environment and to improve regional representativeness of station observation. The present work provides observational evidences that high resolution Landsat images can be used to evaluate the thermal environment of meteorological stations.

Review of recent studies of the climatic effects of urbanization in China

Volume 7, Issue 3, September 2016, Pages 154-168
Zhong Wei Yan | Zhong Wei Yan | Jun Wang | Jiang Jiang Xia | Jin Ming Feng

© 2016 National Climate Center (China Meteorological Administration) This paper summarizes recent studies on the effects of urbanization on climate in China. The effects of urbanization on local climate trends have been re-estimated based on homogenized observations and using improved methods. In this respect, the effect of urbanization on the observed warming trend of local surface air temperatures during the last few decades is determined as being about 20% at urban stations such as the Beijing Observatory. The large-scale weakening trend of wind speed is also about 20% more prominent at the city center than its surroundings. The effect of urbanization on precipitation is not profound, but results of high-resolution regional climate modeling suggest that this effect may depend on the urban extent. Although the urban heat island (UHI) should favor local atmospheric convection and hence precipitation, the increasingly extending urban land-use may reduce precipitation over the urban cluster in North China. It is found that urbanization can play a more notable role in extreme events than usual weather. High-resolution simulations show a positive feedback between the UHI and the super-heat wave in Shanghai during July–August 2013. Relevant studies dealing with urban climate adaptation are discussed in relation to recent findings.

Brown carbon in the cryosphere: Current knowledge and perspective

Volume 7, Issues 1-2, March 2016, Pages 82-89
Guang Ming Wu | Guang Ming Wu | Zhi Yuan Cong | Zhi Yuan Cong | Shi Chang Kang | Shi Chang Kang | Kimitaka Kawamura | Kimitaka Kawamura | Ping Qing Fu | Yu Lan Zhang | Xin Wan | Shao Peng Gao | Bin Liu

© 2016 National Climate Center (China Meteorological Administration) Recently, the light-absorbing organic carbon, i.e., brown carbon (BrC), has received an increasing attention, because they could significantly absorb the solar radiation in the range of short wavelengths rather than the purely scattering effect. BrC is ubiquitous in the troposphere. It could undergo long range transport within the atmospheric circulation. After the deposition on the surface of snow or ice in the cryospheric region, as the major light absorbing impurities with black carbon and dust, BrC could reduce the snow albedo and accelerate the glacier melting. In this context, this paper summarized the current knowledge of BrC (in aerosols and snow) in the cryospheric regions including the Arctic, Antarctic, and Alpines. Although some works have been conducted in those region, the current dataset on the optical properties of BrC like Absorption Ångström Exponent (AAE) and Mass Absorption Efficiency (MAE) is still limited, which hampers stimulating an accurate evaluation of its climate effects. Especially in the Himalayas and Tibetan Plateau, where very limited information concerning BrC is available. Considering biomass burning as a dominant source of BrC, a large amount of emissions from biomass burning in South Asia could reach the Himalayas and Tibetan Plateau, where the climate effect of BrC merits more investigation in the future.

China's INDC and non-fossil energy development

Volume 6, Issues 3-4, September 2015, Pages 210-215
Jian Kun He

© 2015 National Climate Center (China Meteorological Administration). Global climate change promotes the energy system reform. Achieving a high proportion of renewable energy becomes the major countries' energy strategy. As proposed in its Intended Nationally Determined Contributions (INDC), China intends to raise the proportion of non-fossil energy in primary energy consumption to about 20% by 2030. That ambitious goal means the non-fossil energy supplies by 2030 will be 7-8 times that of 2005, and the annual increase rate is more than 8% within the 25 years. Besides, the capacity of wind power, solar power, hydropower and nuclear power reaches 400 GW, 350 GW, 450 GW, and 150 GW respectively, and China's non-fossil power capacity is even greater than the U.S.'s total power capacity. In addition, the scale of natural gas increases. Consequently, by 2030, the proportion of coal falls from the current 70% to below 50%, and the CO2 intensity of energy consumption decreases by 20% compared with the level of 2005, which play important roles in significantly reducing the CO2 intensity of GDP. Since China has confirmed to achieve the CO2 emissions peak around 2030, at that time, the newly added energy demand will be satisfied by non-fossil energy, and the consumption of fossil fuel will stop growing. By 2030, non-fossil energy accounts for 20%, and the large scale and sound momentum of new and renewable energy industry will support the growth of total energy demand, which plays a key role in CO2 emissions peaking and beginning to decline, and lays the foundation for establishing a new energy system dominated by new and renewable energy in the second half of the 21st century as well as finally achieving the CO2 zero-emission.

Decoupling economic growth from CO2emissions: A decomposition analysis of China's household energy consumption

Volume 7, Issue 3, September 2016, Pages 192-200
Xiao Wei Ma | Xiao Wei Ma | Yi Ye | Yi Ye | Xiu Qing Shi | Xiu Qing Shi | Le Le Zou

© 2016 National Climate Center (China Meteorological Administration) This paper analyzes Chinese household CO2emissions in 1994–2012 based on the Logarithmic Mean Divisia Index (LMDI) structure decomposition model, and discusses the relationship between household CO2emissions and economic growth based on a decoupling indicator. The results show that in 1994–2012, household CO2emissions grew in general and displayed an accelerated growth trend during the early 21st century. Economic growth leading to an increase in energy consumption is the main driving factor of CO2emission growth (an increase of 1.078 Gt CO2) with cumulative contribution rate of 55.92%, while the decline in energy intensity is the main cause of CO2emission growth inhibition (0.723 Gt CO2emission reduction) with cumulative contribution rate of 38.27%. Meanwhile, household CO2emissions are in a weak state of decoupling in general. The change in CO2emissions caused by population and economic growth shows a weak decoupling and expansive decoupling state, respectively. The CO2emission change caused by energy intensity is in a state of strong decoupling, and the change caused by energy consumption structure fluctuates between a weak and a strong decoupling state.

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