Based on the current climate condition, the characteristic of environment and the intensity of human activities during the social and economic development in Beijing area, an evaluation index system of climatic carrying capacity was built in Beijing area. The climatic carrying capacity influenced by human activities was assessed, the spatial distribution of climatic carrying capacity and its elements were analyzed, the comparative carrying capacity of different districts/counties and the main restriction factors of carrying capacity were highlighted. The results suggest that the index of Beijing climatic carrying capacity in this research changes between 0.24 and 2.24, which is high in the districts of Yanqing county, Miyun county and Changping districts, but low in center six citys and Shunyi and Fangshan districts, and moderate in Haidian, Daxing, Huairou, Mentougou, Pinggu and Tongzhou districts. The spatial difference of climatic carrying capacity is small in Dongcheng, Xicheng, Fengtai, Shunyi and Chaoyang districts, but it is large in these suburb districts such as Yanqing county, Huairou district and Mentougou district, due to the differences of geographical characteristics and ecological environment primarily. As to the elements of climatic carrying capacity, Huairou district, Yanqing county, and Mentougou district mainly are restricted by climate resources; the main restriction factors of climatic carrying capacity in city/town area and Fangshan district are because of the intensity of human activities and ecological environment. In terms of specific indicators, the climatic carrying capacity in the city/town area is mainly caused by population density, greenbelt area and the production and living emissions. The main influence factor of climatic carrying capacity in the Shijingshan district is poor air quality, but in Fangshan district, besides poor air quality, higher energy consumption is another important factor.
Based on the meteorology observation, high resolution urban geographic information and satellite remote sensing data, as well as taking account of the meteorology and urban factors, the results of the wind environmental capacity indexes and zoning in Beijing show that, both the wind speed and mixing layer height are higher in the north and east regions, while lower in central city and southwest areas. The surface roughness length is higher in central and satellite cities, while smaller within the 2nd ring road than in other central urban areas because of the effect of many bungalows distribution, which forms an obvious hollow and ring structure. In the northern and western mountain districts, the roughness length is higher than that in plain areas.Weighting and overall considering the three factors of wind speed, mixing layer height and roughness length, the wind environmental capacity index thresholds were calculated at different levels. It is lower in Fangshan, Mentougou, Haidian, Shijingshan, Fengtai, Dongcheng and Xicheng, especially the capacity index is the lowest in the region between the 2nd ring road and the 4th ring road, which is also consistent with the spatial distribution of Beijing's economic, financial and commercial centers. The high value of wind environmental capacity index is mainly distributed in the northern part of Yanqing, Huairou, Miyun and almost whole Tongzhou district, while other plain areas belong to medium wind environmental capacity index.
According to the interaction between climate and human activities as well as the double attributes of climate, a comprehensive framework and indices system of climatic carrying capacity were established to support the new urbanization. In this framework, the factors concerning climatic resource supplying, climatic disaster constraining, and urban coordinated development were included and quantified by using various methods such as entropy weight, coupled coordination model, and GIS technology. The comprehensive indices were then adopted in Wanjiang city belt to analyze the spatial pattern and key factors of climatic carrying capacity. Results indicated that the spatial pattern of urbanization development was well matching the climatic carrying capacity. The areas where have relative high climatic carrying capacity are also dominated by high urbanization agglomeration. However, the climatic carrying capacity show large spatial variability, and needs to be further optimized at the whole regional scale. Based on the characteristics of urbanization agglomeration and climatic carrying capacity, Wanjiang city belt could be divided into 4 grades and 12 types of areas. For different areas dominated by different types of climatic carrying capacity, the "short board" and main limiting factors are further revealed in this paper.
Atmospheric stability, mixed layer thickness and the atmospheric environmental capacity coefficient are calculated by using the fixed timing observation data during 1961-2010 in Anhui province. The air quality index is also involved here to explore the relationship between atmospheric environmental capacity and air quality. Results indicated that neutral stability accounts for the highest proportion and stability one comes second. Neutral stability presented a significantly decreasing trends while the stability and instability showed increasing trends. Seasonal difference were existed for instability and stability, but not for neutral instability. The annual mean atmospheric mixed layer thickness (AMLT) exhibited a significantly declining trend. Common characteristics were also found with seasonal mean AMLT in summer, autumn, and winter, while the spring mean AMLT demonstrated an abrupt change in the 2000. AMLT in spring and summer were generally higher than that in autumn and winter. The atmospheric environmental capacity coefficient showed obvious spatial differences with high values in the middle reaches of the Huaihe River, southern Dabie Mountain and midwest area of the region along the Yangtze River, which comparatively showed low values in most areas north to Huaihe River, northern Dabie Moutain and south area to the south of the lower reaches of the Yangtze River. There was a remarkably declining trend with the atmospheric environmental capacity coefficient all over Anhui province, which demonstrated prominent interdecadal variation characteristics. Seasonal atmospheric environmental capacity coefficient presented a "double peak value" pattern and reached its minimum mostly in autumn and winter, which went against the diffusion, transmission and elimination of the air pollutants, thus the air quality might get worse with limited capacity. Generally, significantly increasing trend for stability, as well as declining trend with AMLT and rapidly decreasing trend for wind speed might be the possible reasons for the continuing decreasing trend with atmospheric environmental capacity coefficient and corresponding self-purification capability in Anhui province.
A 151-year (1950-2100) dynamical downscaling simulation over East Asia is conducted by using the regional climate model RegCM4.4 at 25 km grid spacing, which is nested within CSIRO-Mk3.6.0. Climate changes over China during the 21st century under the RCP4.5 scenario from CSIRO-Mk3.6.0 and RegCM4.4 are analyzed. Both simulations project that continuous warming with large regional variations will occur in the future. The two simulations obtain similar inter-annual fluctuations of regional average warming, with RegCM4.4 obtaining somewhat smaller values than CSIRO-Mk3.6.0. Projected precipitation changes are even more regionally variable than temperature changes. In western China, both models project increased precipitation, while the projections from two models show different regional details in eastern China. In both simulations, projected annual mean precipitation on national scale does not change significantly due to the contrast changes between dry and wet seasons. To analyze uncertainties of the projected climate change in China, the simulation of RegCM4.4 is compared with a previous simulation of the RegCM3 at the same horizontal resolution. The overall consistency in precipitation change between RegCM3 and RegCM4.4 is projected across western China, while inconsistency is identified in most of eastern China.
By using a new monthly temperature dataset from 1961 to 2014 over China by 0.5°×0.5° spatial resolution, the variation of the air temperature during the global warming hiatus period (1998-2014) was analyzed. It is found that, during the global warming hiatus period, the increasing trend of the mean and maximum air temperature over China indeed shifted, however the increasing trend of minimum air temperature over China didn't ceased, but only slowed down. The decrease in heating rate was mainly caused by the cooling trend in winter. The analysis showed that the warming type of China changed:the temperature in northern China showed a decrease trend, the temperature showed a relatively strong increase trend in Tibetan Plateau and southwestern region. For the seasonal means, the warming trend was very notable in summer but relatively weak in winter. For the elements, the strongest increase trend of temperature was the minimum temperature.
Using daily temperature data of 120 stations in the middle and lower reaches of the Yangtze River during 1971-2015, the variations of average temperature before and after the operation of Three Gorges Dam in four seasons (spring, summer, autumn and winter) were analyzed after removing the impacts of global warming background, the mutation times of high and low temperature days were investigated by the MK test method. Furthermore, the change in soil moisture was investigated by utilizing ERA-Interim soil moisture reanalysis data during 2006-2015, and the vegetation response to the temperature variations was analyzed by utilizing MODIS dataset during 2006-2015. The average temperature in the middle and lower reaches of the Yangtze River showed significant changes after the operation of the Three Gorges Dam, warming phenomenon occurred in the southern study area while cooling phenomenon occurred in the northern study area. The MK test results indicated that the high temperature days in the southern study area and low temperature days in the northern study area both mutated around the time when the Three Gorges Dam began to fully operate. Soil moisture obviously increased in the southern study area. The spatial distribution of the enhanced vegetation index (EVI) trend was consistent with the change of the average temperature in spring, summer and winter, the EVI increased in the southern study area, most significantly in winter (33.06%), but decreased in the northern study area, most significantly in summer (5.11%).
In this paper, based on hourly precipitation observations during 1977-2013 from the Beijing area, hourly precipitation in summer (June-Auguest) is classified into three categories:light (below the 50th percentile values), moderate (the 50th to 95th percentile values), and heavy (above the 95th percentile values). The characteristics of the classified precipitation changes are analyzed and the results reveal that both light and moderate precipitation decreased significantly during the research period which mainly caused the decrease in summer totals, but heavy precipitation showed no pronounced trend. Since 2004, the contribution of heavy rainfall to the summer totals in the urban area increased as compared to the suburban area, which is opposite to light rainfall. There are obvious differences in the diurnal variations of classified precipitation. Light precipitation shows a double peak structure in the early morning and at night, while moderate and heavy rainfall show a single peak at night. Light precipitation at the early morning peak-time decreased significantly in the whole Beijing area. Compared with the suburban area, light precipitation in the urban area occurred less frequently whereas heavy precipitation occurred more frequently at evening peak-time after 2004. The asymmetry of the rainfall is obvious, especially, for heavy precipitation. The asymmetry of heavy precipitation events in the urban area exhibit a significant increasing trend.
A new statistical method was proposed to project the sea level rise (SLR) within the Yangtze Estuary using the monitoring data at two tide gauge stations (Wusong and Lüsi), and then four representative prediction values of SLR published in previous research were integrated, to generate a relatively complete scenario matrix for studies of SLR in this area. Setting the year 2013 as the baseline, the optimum projection range of SLR projected to the year 2030, 2050 and 2100 is 50-217 mm, 118-430 mm and 256-1215 mm, respectively. Moreover, the impacts of SLR in each projected scenario were evaluated, and for simplicity, only the change of coastal wetlands area was considered in this paper. Results showed that, with SLR becoming increasingly remarkable, the coastal wetlands in Yangtze Estuary would shrink continuously. Besides, in scenarios without consideration of climate change, which means that the SLR are projected merely on basis of historical data, the shrink of wetland area is notably slower, compared with that in scenarios which considered global warming. In general, the shrink of wetland area is larger in the long term (2100) than that in the short term (2030 and 2050).
Based on Maximum Entropy (MaxEnt) model and combined with topographic, vegetational, meteorological and other environmental factors, potential distribution of Oncomelania in Hubei province in base period (1986-2005) was simulated, and potential distribution risk zones of Oncomelania in Hubei province under RCP2.6, RCP4.5 and RCP8.5 scenarios during 2021-2040, 2051-2070 and 2081-2100 were projected respectively. The results showed that, the projection with MaxEnt model had a higher simulation accuracy with its mean AUC of ROC value of 0.894±0.024, which was credible and acceptable for future Oncomelania potential distribution projection in Hubei province under the three RCPs. Oncomelania potential distribution illustrated an extension at low and middle risk by 4.5% and 1.6% respectively and reduction of risk-free by 9.3% compared with the base period. Oncomelania potential distribution zones at middle and high risk would move northward.
The average annual temperature in Beijing city increased at the rate of 0.37℃ per 10 years, the intensity and range of heat island effect increased during 1951-2014. With the development of economy and society, extra pressure that climate change brings to energy supply system trends to be significant. This study focuses on the vulnerability of energy system under climate change. The vulnerabilities of climate change in the energy sector in Beijing are that electric load of power demand is over maximum load designed for power supply system under high temperature; under the condition of low temperature, natural gas supply is short; energy production, energy supply and energy transport are threatened by extreme weather. According to the vulnerabilities of the energy system of Beijing, combined with the international advanced experience, the key measures and suggestions were put forward in order to enhance the climate change adaptability of energy system in Beijing.