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    A review on typhoon wind field modeling for disaster risk assessment
    FANG Weihua, LIN Wei
    PROGRESS IN GEOGRAPHY    2013, 32 (6): 852-867.   DOI: 10.11820/dlkxjz.2013.06.002
    Abstract2947)      PDF (956KB)(2299)      
    Quantitative probabilistic typhoon risk model needs a large number of wind samples as input. However, in many areas, historical observation data is inadequate in both spatial and temporal dimensions, which may introduce great bias into risk assessment results. Combined with stochastic track model, parametric wind field model can provide a large number of wind speed samples to quantify wind risk, thanks to its simplicity in computation and solid scientific foundation. According to the general process of typhoon wind modeling, in this paper, firstly the estimation methods of maximum wind speed, radius of maximum wind speed and Holland B parameter for wind field model are reviewed, and the progress in gradient wind field model and boundary layer model is illustrated. Secondly, the theories and applications of wind speed adjustment for surface roughness, terrain, gusts and sea-land transition are analyzed. Thirdly, major software systems with wind field components are also summarized. Finally, it is suggested that the integration of meteorology, wind engineering, oceanic and disaster risk sciences be enhanced. Surface roughness estimation by remote sensing, and terrain adjustment are proposed as priority research areas for China in the future.
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    Cited: CSCD(13)
    Climate factors change and its impact on lake area and vegetation growth in the Qaidam Basin during 1981-2010
    XU Haojie, YANG Taibao
    PROGRESS IN GEOGRAPHY    2013, 32 (6): 868-879.   DOI: 10.11820/dlkxjz.2013.06.003
    Abstract1276)      PDF (7217KB)(1106)      
    Changes of climate factors in the Qaidam Basin during 1981-2010 were analyzed based on the monthly temperature and precipitation data from meteorological stations. Rate of linear tendency and Mann-Kendall test were used to illustrate the change trends and detect abrupt changes of meteorological elements respectively. In addition, lake area changes and vegetation activity changes in the Qaidam Basin in response to climate changes were discussed using Landsat TM/ETM+ images, NOAA/AVHRR-NDVI and EOS/MODIS-NDVI products. The results showed that (1) The Qaidam Basin experienced an overall rise in temperature, especially in autumn and winter during 1981-2010. Temperature changed abruptly from low to high in 1987 and the increase has become more rapid since 1998. (2) The annual available precipitation showed a "decrease-increase-decrease-increase" change in recent 30 years, but the inter-annual trend of annual available precipitation was similar to annual mean temperature at a rate of 5.65 mm/10a. Available precipitations were low in 1981-1985, 1990-2001, but high in 1985-1990, 2001-2010. An abrupt change to warm-wet happened in the mid-late 1980s. However, an overall trend of warm-dry was detected from the mid-1990s to the end of the 20th century. A significant warm-wet trend of climate has arrived once again since the early 21th century. (3) Variations of lake area and vegetation growth were significantly affected by the change of wet and dry climate. The "expansion-atrophy-expansion" pattern in lake areas correlated with summer available precipitations which happened in 1985-1990, 1990-2001, 2001-2010 respectively. (4) The "degradation-amelioration-degradation-amelioration" pattern in vegetation growth was closely related with growing season available precipitation which happened in 1981-1985, 1985-1990, 1990-2001, 2001-2010.
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    Cited: CSCD(17)
    Relationship between annual runoff of the mainstream of Tarim River and sunspots activity
    XI Xiumei, LIU Hailong
    PROGRESS IN GEOGRAPHY    2013, 32 (6): 880-886.   DOI: 10.11820/dlkxjz.2013.06.004
    Abstract1085)      PDF (2732KB)(812)      
    In this paper, we used Morlet wavelet transform method to analyze the relationship between annual runoff in the mainstream of the Tarim River and sunspots activity dring 1957-2011. Results indicated that both annual runoff of the mainstream of Tarim River and number of sunspots were decreased dring 1957-2011. There were main periods of 4 a, 8 a, 18 a, and 21 a in annual runoff. On the scales of 8~9 a and 18~21 a, the annual runoff and number of sunspots had similar primary cycles. Sunspots activity had almost no effect on the characteristics of annual runoff change of the 4 a cycle, but the characteristics of the 18~21 a cycle were mainly influenced by sunspots activity. The annual runoff change of 8 a primary cycle was once closely related to sunspots activity, but the correlation was disrupted after 1980 due to strong interferences of human activities. This paper forecasts that 2012-2020 may be a withered water period for annual runoff in the mainstream of Tarim Riverin, and the average annual runoff may be about 35×10 8~40×10 8 m 3
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    Cited: CSCD(8)
    Regionalization of temperature changes in China and characteristics of temperature in different regions during 1951-2010
    HAN Cuihua, HAO Zhixin, ZHENG Jingyun
    PROGRESS IN GEOGRAPHY    2013, 32 (6): 887-896.   DOI: 10.11820/dlkxjz.2013.06.005
    Abstract1430)      PDF (9209KB)(1643)      
    Based on daily meteorological dataset of 623 stations during 1951-2010 in China, using the orthogonal rotational factor analysis, we studied of regionalization of the trends of annual, summer semiannual, and winter semiannual temperature changes for the four 30-year time periods, 1951-1980, 1961-1990, 1961-2000, and 1971-2010. The differences among the four periods of the regionalization were analyzed. The results show that China can be divided into 8 regions based on the characteristics of both annual and summer semiannual temperature changes, and the boundaries of the regions were stable during 1951-2010; the country can be divided into 7 regions based on the characteristics of winter semiannual temperature changes, and the boundaries of the regions showed clear changes in every 30-year time period. The regionalization boundaries of winter semiannual temperature changes showed high level of consistency with those of annual temperature changes. So winter semiannual temperature changes can substitute annual temperature changes for historical climate reconstruction. In addition, the characteristics of temperature changes in the different regions of China were analyzed. The results indicated that the trend of temperature change was overall upward, with a remarkable rate of 0.30℃/10a in Northeast and a rate of 0.13℃/10a in South China. Temperature increases of different regions were not in the same pace. For example, a significant warming trend in Northeast and Yunnan-Tibet Plateau was in 1961-1990, while warming trends of other regions were in 1971-2000 and 1981-2010. The winter semiannual temperatures had more dramatic increases than summer semiannual temperatures.
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    Cited: CSCD(43)
    Spatial characteristics of residents’outings and carbon emissions in Urumqi City
    SHI Tiange, ZHANG Xiaolei, DU Hongru, ZHANG Wenbiao, SHI Hui
    PROGRESS IN GEOGRAPHY    2013, 32 (6): 897-905.   DOI: 10.11820/dlkxjz.2013.06.006
    Abstract934)      PDF (1534KB)(877)      
    In the process of urbanization, urban spatial structure and organization mode are being transformed tremendously, and use of private cars causes traffic congestion and increased carbon emissions. It has become a hot research topic to investigate the relationships between urban spatial structure, residents' outings and carbon emissions from the perspective of micro-mechanisms. In this paper, based on a survey of daily activities of 600 households' from Urumqi City in 2011, basic characteristics of the residents' outings and spatial characteristics of their commuting were analyzed. In addition, the outing-related transport carbon emissions and the influencing factors in different urban areas were examined. The survey covered the activities recorded in consecutive 48 hours including a Sunday and a Monday. The results indicated that: (1) Urumqi residents' outings are mainly commuting. Outings in different areas show spatial diversity: the numbers of trips per capita in the two areas, the central area of inner city and suburban satellite towns, are higher than those in other areas, but the total trip distances in the two areas are significantly shorter than those in other areas. Imbalance of urban development between northern areas and southern areas affect suburbanites' outings. The residents in the areas are more dependent on the central city areas for jobs and services, due to lack of public service infrastructures in southern suburbs, whereas the residents in the northern suburbs tend to work near their own living areas, thanks to adequate employment opportunities and service facilities. (2) In comparison to the large cities on the east, the average actual commuting distance in Urumqi is 4.9 km, shorter commuting distance but longer commuting time. Commuting distance in space shows a significant increasing trend from inner areas to outer areas. (3) The direct carbon emission per capita from residents' daily outings in Urumqi was 682.95 g in 2011. Carbon emissions from residents' daily outings vary significantly in different urban areas, with low-carbon emission in the central area and the satellite towns, moderate-carbon emission in near suburbs and high-carbon emission in far suburbs.
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    Cited: CSCD(3)