The Upper Troposphere (UT) water vapor distribution has a very important influence on global energy and water cycle. The spatial-temporal distribution of water vapor in UT has been analyzed using humidity profile data retrieved from AIRS (Atmospheric Infrared Sounder) which is on board of Aqua satellite. In order to make sure that the accuracy of the humidity profile data meets the needs of the climate characteristics analyses, we run a validation on the relative humidity against the sounding observation data in JICA field campaign in 2008. The result shows that the two data sets have a good correlation, and the absolute error is within 5% in 200 hPa. Therefore, the AIRS relative humidity data in 200 hPa can be used for the climate characteristics analysis. Our analysis on the spatial-temporal characteristics of the relative humidity during the period of January 2003 through December 2013 prove that, with the impact of the summer monsoon, the relative humidity in China has significant seasonal and yearly variation characteristics. The relative humidity in UT is more in summer than that in winter in China, the high relative humidity area can move northward to 35°N in summer. There is a opposite distribution in Xinjiang province that more humidity in winter and less in summer. Over all, the relative humidity in UT over China is the highest in summer, lower in fall, and the lowest in winter. From 2003, the relative humidity has shown a significant elevating trend in South China Sea and Xinjiang province. In South China, North China, central and western of Inner Mongolia, relative humidity in UT also increased, but did not change significantly, and in the Tibetan Plateau and the Northeast China, water vapor in UT decreased slightly, but the changes were not significant. The increase of water vapor in the UT will have the potential to amplify the greenhouse effect, which should be paid more attention in the study of climate change.
The capabilities of the latest global climate models in simulating surface air temperatures in China have been assessed from the observed dataset and outputs from 29 models that participate in the fifth phase of the Coupled Model Inter Comparison Project (CMIP5). Based on the CMIP5 results, the surface air temperature changes in the 21st century are analyzed. The results show that the 29 CMIP5 models well simulated the significant rise trend, temporal evolution and spatial distribution of the annual mean temperature over China. The root mean square errors show that the multi-model ensemble mean shows better performance on various time scales than a single model. The capabilities of the 7 models are comparable to those of the others models have relatively better performances among them. The projection results are consistent between the different emission scenarios and models in the early stage of the 21st century. However the projected temperature becomes more sensitive to the scenarios and models since mid of the 21st century.
Based on the data of monthly precipitation and other monthly meteorological factors of 661 meteorological stations over China from 1961 to 2013. The Hetao area of North China, which is drying significantly, is chosen and its temporal evolution characteristics are studied by using REOF. The effects of the summer monsoon and the meteorological factors on the aridity index (IA) are discussed, and the results are as follows. The summer monsoon index of western South Asian (ISASM1) mainly affects the overall trend and the annual change of climatic dry during 1961-1991. With global warming, the degree of the influence is weakened, and the decadal variation of IA is mostly affected by temperature and other thermal factors. The influence of annual variation of the thermal factors on the IA decreases, while the influence of decadal variation of the thermal factors on the IA increases after the 20th century. It shows that climatic warming causes the increasing vapor pressure difference, the decreasing relative humidity. Air needs more vapor to be saturated, while increasing evaporation in surface, air drying degree, and arider climate in Hetao area of North China.
Based on the precipitation data of 48 selected stations in South China, the NCEP/NCAR analysis data during 1958-2008 and the NOAA monthly sea surface temperature (SST) data for the period 1957-2008, The variation features of summer precipitation in South China and its relationship with the SST in the tropical Pacific in winter have been studied using EOF decomposition, correlation, synthesis and other statistical methods. The results indicate that the first mode show consistent anomalous signs in the whole South China region, the Second mode is out-of-phase at the north and south of South China and the third mode is out-of-phase at the east and west of South China. These three modes show obvious interannual and decadal variation. The tropical Pacific SSTA, which corresponds to the first mode rainfall anomaly, has a “-+-”zonal three-pole type pattern along the equatorial Pacific, similar to El Nino-Modoki. The significant positive correlation between SST index and rainfall index also has decadal characteristic. In the period with more precipitation, the southwest summer monsoon and the west Pacific subtropical high (WPSH) are stronger. The ridge position of the WPSH extends westward. The ridge of South Asian high extends eastward and its strength is stronger. All of them are in favor of water vapor transport and convective motion in South China, leading to increased precipitation in South China. Conversely, there will be less precipitation in South China.
The development of cryosphere science shows a tendency of the combination of its natural and socioeconomic aspects, highlighting its service values. With the deepening of transition of cryosphere science from nature science towards stronger linkages with socioeconomic and cultural sciences nowadays, cross-disciplinary research of cryosphere is emerging, which meets the increasing demand of applied study of cryosphere in the future. By illuminating cryosphere service function (CSF), this study identified various forms of CSF and proposed a value evaluation system. Cryosphere services valuation can benefit decision-makers, and contribute to the increased public awareness of environmental protection. It has profound and practical significance and implications for implementing the sustainable utilization strategies of CSFs and macroeconomic policymaking for global environmental protection, and for avoiding scarifying environment while pursuing short-term economic profits in the process of achieving rapid economic development.
Both carbon tax and ETS are the environmental management tools to control greenhouse gas emissions, but they may bring different effects about mitigation cost for various industries. Building the GHGs mitigation cost function which based on the steady-state expect social cost function of pollution control policies, and employing it to compare the emission reductions cost of cement industry under the carbon tax or ETS to find the key influence factors for cutting cost. Taking Guangdong and Shandong provinces’cement industry as empirical example, the following conclusions can be conducted: when there is little difference between the carbon price and carbon tax rate, the carbon tax will be more cost effective than ETS, due to ETS’s higher construction cost. In the short term, because the higher cost of emission reductions of using new technology under mandatory administrative rules, ETS is more cost effective. There are some key factors to impact enterprise’s mitigation cost: carbon price, carbon tax rate, the price of the best available technology, enterprise anticipation, ETS construction costs, which will affect the comparative advantage of ETS and carbon tax on the emission reductions costs. At last, We suggest to design a kind of complementary carbon emission management policies, making the carbon tax and ETS play their respective advantages.
Four-years negotiation of Durban Platform for Enhanced Action has accomplished in Paris Climate Conference and the Paris Agreement (the Agreement) has been adopted by the 21 Conference of the Parties with a series of decisions. The Agreement establishes a new mode of global governance on climate change with all parties participating, self-contribution plus review and including all elements (mitigation, adaptation and means of support). This mode based on the principles of the Convention, employs the differentiation of developed and developing countries and mobilizes all parties involving the addressing climate change actions by the National Determined Contributions, promote sustainable development. The Agreement also encourages others beside Parties to participate the process on addressing climate change, facilitates the market and non-market mechanisms, and mobilizes green climate finance on low carbon fields. The Agreement is an incentive, transparent, non-confrontational, non-punitive mode for institutional arrangements. The adoption of the Agreement indicates that the global climate governance is entering a new stage by passing out the strong signal of the global efforts on the green and low-carbon goal, climate-adapted and sustainable development. However, since the Agreement has balanced the interests of all parties in a comprehensive manner, there will be a lot of difficulties and barrier on the compliance details, the implementations in future. The interests of the developing countries, particularly large developing countries probably will be sacrificed if there is any impropriety on the future implementation of the Agreement.
To adapt to climate change becomes important issue both for the international negotiation and domestic practical adaptation. Clarified relevant terms related with adaptation have positive roles for related scientific research and adaptive actions. The paper identify adaptation is a definition of behavior or measures, no necessarily need for quantitative results; adaptive capacity has clear evaluation index system, and eventually produce quantitative assessment results; Adaptability focus on ability property, its basic conclusion is with or without, strong or weak. The adaptability backed by the quantitative conclusion or determined specific strength is equivalent to adaptive capacity. For the vulnerability assessment, exposure reflects the basic situation of the main object associated with climate change, sensitivity shows the effects of climate change on the subject object, adaptive capacity is the combination of economic capital, natural resources, technical ability and social security, all the four elements involve specific indicators that need take into consideration and selection according to the subject property. Disaster risk management and adaptation to climate change have several differences within the main category, driving factors, the purpose of the action, but both focus on improving the resilience on climate change/climate disasters and enhancing the ability to prevent, bear and restore from adverse effects.
Increase of the intensity and frequency of extreme flood events has been a big challenge of regional water resources security. Based on daily discharge data during 1957-2011 in the Kaidu watershed, annual maximum daily discharge, maximum daily discharge in spring and maximum daily discharge in summer at Bayblk and Dashankou hydrological stations are extracted, respectively. Linear trend method, Mann-Kendall test and Pettitt test are used to analysis the variation of the 6 series. Then, the series are selected to describe the extreme distributions of GEV, and frequency of extreme floods is analyzed. The results indicated that, there are no significant trend and no change point in the 6 series in which the annual maximum daily discharge at Bayblk station, the annual maximum daily discharge at Dashankou station and the maximum daily discharge in spring at Bayblk station fitted the Frechet distribution, and the maximum daily discharge in spring at Dashankou station, the maximum daily discharge in summer at Bayblk station and the maximum daily discharge in summer at Dashankou station fitted the Gumbel distribution. Since 1980s, frequency of extreme floods in the Kaidu River obviously increased; the number of floods in summer continuous increase at the Bayblk station, and the number of floods both in spring and summer increase at Dashankou station; occurrence time of spring floods shift to an earlier date at both two hydrological stations. The increase of precipitation in winter, and the rise of temperature in spring have important contribution to spring flood changes; the increase of extreme rainfall in summer would be dominant factors for changes of summer floods.