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11.
Seasonality changes in China under elevated atmospheric CO 2 concentrations were simulated using nine global climate models,assuming a 1% per year increase in atmospheric CO 2.Simulations of 20th century experiments of season changes in China from the periods 1961 80 to 1981 2000 were also assessed using the same models.The results show that the ensemble mean simulation of the nine models performs better than that of an individual model simulation.Compared the mean climatology of the last 20 years in the CO 2-quadrupling experiments with that in the CO 2-doubling ones,the ensemble mean results show that the hottest/coldest continuous-90-day (local summer/winter) mean temperature increased by 3.4/4.5°C,2.7/2.9°C,and 2.9/4.1°C in Northeast (NE),Southwest (SW),and Southeast (SE) China,respectively,indicating a weakening seasonal amplitude (SA),but by 4.4/4.0°C in Northwest (NW) China,indicating an enlarging SA.The local summer lengthened by 37/30/66/54 days in NW,NE,SW,and SE China,respectively.In some models,the winter disappeared during the CO 2-quadrupling period,judging by the threshold based on the CO 2-doubling period.The average of the other model simulations show that the local winter shortened by 42/36/61/44 days respectively,in the previously mentioned regions. 相似文献
12.
武汉市城市热岛强度非对称性变化 总被引：15，自引：0，他引：15
利用武汉市区气象站及其周边4个县气象站1960-2005年的气温资料,计算了46 a及分时段的季节和年平均气温、平均最高和最低气温倾向率,城市热岛强度倾向率及其贡献率。结果表明：46 a来,城区和郊区的平均气温均以上升趋势为主,最低气温增幅最大,最高气温增幅最小,甚至下降;冬季增幅最快,夏季增幅最慢,甚至下降,这是第一类非对称性。 城市热岛效应也存在增强趋势,以年平均、最低和最高气温表示的城市热岛强度倾向率分别为0.235℃/10 a、0.425℃/10 a和0.034℃/10 a,热岛效应贡献率分别达到60.4%、67.7%和21.8%,这是第二类非对称性。 46 a来的增温和城市热岛强度加强主要是最近23 a快速增温所致,进入本世纪增温进一步加剧。
摘要 计算了武汉市气象站、周边4县气象站平均的1960～2005年间以及前后两半时段四季和年平均、最高、最低气温倾向率,城市热岛强度倾向率和贡献率。结果表明：1）46年来,城区和郊区的平均气温均以增趋势为主,平均气温倾向率为正,最低气温增幅最大,最高气温增幅最小甚至下降,冬季增幅最快,夏季增幅最慢甚至下降,这是第一类非对称性;2）城市热岛效应也存在增趋势,以年平均、最低、最高气温表示的城市热岛强度倾向率分别为0.235、0.425、0.034 ℃/10a,热岛效应贡献率分别达到60.4%、67.7%、21.8%,这是第二类非对称性,3）46年来的增温和城市热岛强度加强主要是后23年快速增温所致,前23年气温变化不明显。武汉市气象站气温资料严重地保留着城市化影响,建议尽快迁站。
关键词 城市热岛强度 最高气温 最低气温 非对称性变化 相似文献
13.
《Marine Policy》1998,22(3):269-280
Traditionally there has always been a barrier between scientists and policy makers. They live in different worlds so to speak. However, a close collaboration between the two will be needed if we want to tackle the problem of a responsible use of the Earth’s natural resources. Also, a truly global collaboration will be needed and a polling of all information sources, including developed and developing countries. The ongoing large scale introduction of information technology in biodiversity studies will allow researchers to combine all kinds of different datasets and information systems. This will also create new tools allowing interpretation and extrapolation for various use, both for science and for policy-making. The Internet will provide the means to combine all knowledge into one electronic information facility that can be accessed by all parties involved. Electronic scientific information systems offer new avenues for training and capacity building. In this paper the problem of reliable biodiversity assessments and the present day limited use of the information for policy-making is discussed. Examples of the applications of innovative information technological tools in the field of biodiversity informatics are given. There is hope that the barrier will fade. 相似文献
14.
Against a background of climate change, Macau is very exposed to sea level rise(SLR) because of its low elevation,small size, and ongoing land reclamation. Therefore, we evaluate sea level changes in Macau, both historical and, especially,possible future scenarios, aiming to provide knowledge and a framework to help accommodate and protect against future SLR. Sea level in Macau is now rising at an accelerated rate: 1.35 mm yr-1over 1925–2010 and jumping to 4.2 mm yr-1over 1970–2010, which outpaces the rise in global mean sea level. In addition, vertical land movement in Macau contributes little to local sea level change. In the future, the rate of SLR in Macau will be about 20% higher than the global average, as a consequence of a greater local warming tendency and strengthened northward winds. Specifically, the sea level is projected to rise 8–12, 22–51 and 35–118 cm by 2020, 2060 and 2100, respectively, depending on the emissions scenario and climate sensitivity. Under the +8.5 W m-2Representative Concentration Pathway(RCP8.5) scenario the increase in sea level by2100 will reach 65–118 cm—double that under RCP2.6. Moreover, the SLR will accelerate under RCP6.0 and RCP8.5, while remaining at a moderate and steady rate under RCP4.5 and RCP2.6. The key source of uncertainty stems from the emissions scenario and climate sensitivity, among which the discrepancies in SLR are small during the first half of the 21 st century but begin to diverge thereafter. 相似文献
15.
Future climate change potentially can have a strong impact on the African continent. Of special concern are the effects on food security and the restricted adaptive capacity of Africa's poverty stricken population. Targeted policy interventions are, therefore, of vital importance. While there is a broad consensus on selection of climate and agricultural indicators, a coherent spatial representation of the populations' vulnerability is still subject to debate, basically because important drivers at household and institutional level are captured at the coarser (sub)-national level only. This paper aims to address this shortcoming by capitalizing on available spatially explicit information on households, food security institutions and natural resources to identify and characterize vulnerable groups in climate change prone areas of East and West Africa. First, we identify and localize groups with varying degrees of vulnerability, using food security and health indicators from georeferenced household surveys. Second, we characterize these vulnerable groups using statistical techniques that report on the frequency of occurrence of household characteristics, social bonding, remittances and agro-ecological endowments. Third we localize areas where climate change conditions affect production of major staple crops even after a maximum adaptation of crop rotations. Fourth, we characterize the vulnerable groups in the climate change affected areas and compare their profiles with the overall assessment to elucidate whether generic or climate change targeted policies are required. Since climate change will impact predominantly on agricultural production, our analysis focuses on the rural areas. For West Africa, we find that vulnerable groups in areas likely to be affected by climate change do not fundamentally differ from vulnerable groups in the study area in general. However, in East Africa there are remarkable differences between these groups which leads to the conclusion that in this part of Africa, poverty reducing strategies for climate change affected areas should differ from generic ones. 相似文献
16.
Jason M. Dortch Lewis A. Owen William C. Haneberg Marc W. Caffee Craig Dietsch Ulrich Kamp 《Quaternary Science Reviews》2009,28(11-12):1037-1054
Four large landslides, each with a debris volume >106 m3, in the Himalaya and Transhimalaya of northern India were examined, mapped, and dated using 10Be terrestrial cosmogenic radionuclide surface exposure dating. The landslides date to 7.7±1.0 ka (Darcha), 7.9±0.8 ka (Patseo), 6.6±0.4 ka (Kelang Serai), and 8.5±0.5 ka (Chilam). Comparison of slip surface dips and physically reasonable angles of internal friction suggests that the landslides may have been triggered by increased pore water pressure, seismic shaking, or a combination of these two processes. However, the steepness of discontinuities in the Darcha rock-slope, suggests that it was more likely to have started as a consequence of gravitationally-induced buckling of planar slabs. Deglaciation of the region occurred more than 2000 years before the Darcha, Patseo, and Kelang Serai landslides; it is unlikely that glacial debuttressing was responsible for triggering the landslides. The four landslides, their causes, potential triggers and mechanisms, and their ages are compared to 12 previously dated large landslides in the region. Fourteen of the 16 dated landslides occurred during periods of intensified monsoons. Seismic shaking, however, cannot be ruled out as a mechanism for landslide initiation, because the Himalaya has experienced great earthquakes on centennial to millennial timescales. The average Holocene landscape lowering due to large landslides for the Lahul region, which contains the Darcha, Patseo, and Kelang Serai landslides, is ～0.12 mm/yr. Previously published large-landslide landscape-lowering rates for the Himalaya differ significantly. Furthermore, regional glacial and fluvial denudation rates for the Himalaya are more than an order of magnitude greater. This difference highlights the lack of large-landslide data, lack of chronology, problems associated with single catchment/large landslide-based calculations, and the need for regional landscape-lowering determinations over a standardized time period. 相似文献
17.
The assimilation of Earth observation (EO) data into crop models has proven to be an efficient way to improve yield prediction at a regional scale by estimating key unknown crop management practices. However, the efficiency of prediction depends on the uncertainty associated with the data provided to crop models, particularly climatic data and soil physical properties. In this study, the performance of the STICS (Simulateur mulTIdisciplinaire pour les Cultures Standard) crop model for predicting corn yield after assimilation of leaf area index derived from EO data was evaluated under different scenarios. The scenarios were designed to examine the impact of using fine-resolution soil physical properties, as well as the impact of using climatic data from either one or four weather stations across the region of interest. The results indicate that when only one weather station was used, the average annual yield by producer was predicted well (absolute error <5%), but the spatial variability lacked accuracy (root mean square error = 1.3 t ha−1). The model root mean square error for yield prediction was highly correlated with the distance between the weather stations and the fields, for distances smaller than 10 km, and reached 0.5 t ha−1 for a 5-km distance when fine-resolution soil properties were used. When four weather stations were used, no significant improvement in model performance was observed. This was because of a marginal decrease (30%) in the average distance between fields and weather stations (from 10 to 7 km). However, the yield predictions were improved by approximately 15% with fine-resolution soil properties regardless of the number of weather stations used. The impact of the uncertainty associated with the EO-derived soil textures and the impact of alterations in rainfall distribution were also evaluated. A variation of about 10% in any of the soil physical textures resulted in a change in dry yield of 0.4 t ha−1. Changes in rainfall distribution between two abundant rainfalls during the growing season led to a significant change in yield (0.5 t ha−1 on average). Our results highlight the importance of using fine-resolution gridded daily precipitation data to capture spatial variations of rainfall as well as using fine-resolution soil properties instead of coarse-resolution soil properties from the Canadian soil dataset, especially for regions with high pedodiversity. 相似文献
18.
Phenological data have shown an increase of ca. 10 days in European growing season length in the latter part of the twentieth
century. In general, these changes have been associated with global warming. Here we present a study of thermal growing season
(GS) trends in the Greater Baltic Area, northern Europe. Yearly dates for the start, end and length of the GS were computed
for 49 stations in the studied area, using daily mean temperature measurements. Trends and tendencies of the GS parameters
were analysed within the twentieth century. We also examined GS trends in long records (starting before 1850) from the region.
The results show a general increase of the length of the GS of ca one week since 1951 in the area, where the most considerable
change has occurred in spring (starting ∼6 days earlier). The largest increases were found at stations adjacent to the Baltic
Sea and North Sea, where some Danish stations showed significant increasing trends in the length of the GS of more than 20 days.
The only tendency for a shorter GS was found in Archangelsk, north western Russia. The three longest records displayed large
inter-annual and decadal variability, with tendencies for increased frequencies of longer growing seasons since the 1950s. 相似文献
19.
1 Introduction Evaporation is one of the important components in the water and heat balances. The transpiration of vegetation and evaporation from soil are collectively called evapotranspiration. Potential evapotranspiration is not only the theoretical li… 相似文献
20.
Spatial and temporal variations and controlling factors of potential evapotranspiration in China: 1956-2000 总被引：7，自引：0，他引：7
Based on the climatic data of 580 stations in China during 1956 and 2000, potential evapotranspiration are calculated using the Penman-Monteith Method recommended by FAO. The spatial and temporal distributions of the potential evapotranspiration over China and the temporal trends of the regional means for 10 major river basins and whole China are analyzed. Through a partial correlation analysis, the major climate factors which affect the temporal change of the potential evapotranspiration are analyzed. Major results are drawn as follows: 1) The seasonal and annual potential evapotranspiration for China as a whole and for most basins show decline tendencies during the past 45 years; for the Songhua River Basin there appears a slightly increasing trend. 2) Consequently, the annual potential evapotranspirations averaged over 1980-2000 are lower than those for the first water resources assessment (1956-1979) in most parts of China. Exceptions are found in some areas of Shandong Peninsula, western and middle basins of the rivers in Southwest China, Ningxia Hui Autonomous Region as well as the source regions of the Yangtze and Yellow rivers, which may have brought about disadvantages to the exploration and utilization of water resources. 3) Generally, sunshine duration, wind speed and relative humidity have greater impact on the potential evapotranspiration than temperature. Decline tendencies of sunshine duration and/or wind speed in the same period appear to be the major causes for the negative trend of the potential evapotranspiration in most areas. 相似文献