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...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.展开更多
Daily climate data at 110 stations during 1961-2010 were selected to examine the changing characteristics of climate factors and extreme climate events in South China. The annual mean surface air temperature has incre...Daily climate data at 110 stations during 1961-2010 were selected to examine the changing characteristics of climate factors and extreme climate events in South China. The annual mean surface air temperature has increased significantly by 0.16℃ per decade, most notably in the Pearl River Delta and in winter. The increase rate of the annual extreme minimum temperature (0.48℃ per decade) is over twice that of the annual extreme maximum temperature (0.20℃ per decade), and the increase of the mean temperature is mainly the result of the increase of the extreme minimum temperature. The increase rate of high-temperature days (1.1 d per decade) is close to the decrease rate of low-temperature days (-1.3 d per decade). The rainfall has not shown any significant trend, but the number of rainy days has decreased and the rain intensity has increased. The regional mean sunshine duration has a significant decreasing trend of -40.9 h per decade, and the number of hazy days has a significant increasing trend of 6.3 d per decade. The decrease of sunshine duration is mainly caused by the increase of total cloud, not by the increase of hazy days in South China. Both the regional mean pan evaporation and mean wind speed have significant decreasing trends of -65.9 mm per decade and -0.11 m s-1 per decade, respectively. The decrease of both sunshine duration and mean wind speed plays an important role in the decrease of pan evaporation. The number of landing tropical cyclones has an insignificant decreasing trend of -0.6 per decade, but their intensities show a weak increasing trend. The formation location of tropical cyclones landing in South China has converged towards 10-19°N, and the landing position has shown a northward trend. The date of the first landfall tropical cyclone postpones 1.8 d per decade, and the date of the last landfall advances 3.6 d per decade, resulting in reduction of the typhoon season by 5.4 d per decade.展开更多
Polar climate systems have experienced a number of dramatic changes （Wang et al., 2017; Turner et al., 2016; Gordon, 2014; Rignot et al., 2013; Meier et al., 2012; Kwok and Rothrock, 2009; Thompson and Solomon, 2002...Polar climate systems have experienced a number of dramatic changes （Wang et al., 2017; Turner et al., 2016; Gordon, 2014; Rignot et al., 2013; Meier et al., 2012; Kwok and Rothrock, 2009; Thompson and Solomon, 2002）, which have influenced climatic conditions across large parts of the globe through large-scale atmospheric and oceanic teleconnections （Dou and Wu, 2018; Zhang et al., 2018;展开更多
The study area is located between the cities of Comitan (16°10'43"N and 92°04'20''W) a city with 150,000 inhabitants and La Esperanza (16°9'15''N and 91°...The study area is located between the cities of Comitan (16°10'43"N and 92°04'20''W) a city with 150,000 inhabitants and La Esperanza (16°9'15''N and 91°52'5''W) a town with 3000 inhabitants. Both weather stations are 30 km from each other in the Chiapas State, México. 54 years of daily records of the series of maximum (<em>t</em><sub>max</sub>) and minimum temperatures (<em>t</em><sub>min</sub>) of the weather station 07205 Comitan that is on top of a house and 30 years of daily records of the weather station 07374 La Esperanza were analyzed. The objective is to analyze the evidence of climate change in the Comitan valley. 2.07% and 19.04% of missing data were filled, respectively, with the WS method. In order to verify homogeneity three methods were used: Standard Normal Homogeneity Test (SNHT), the Von Neumann method and the Buishand method. The heterogeneous series were homogenized using climatol. The trends of <em>t</em><sub>max</sub> and <em>t</em><sub>min</sub> for both weather stations were analyzed by simple linear regression, Sperman’s rho and Mann-Kendall tests. The Mann-Kendal test method confirmed the warming trend at the Comitan station for both variables with <em>Z<sub>MK</sub></em> statistic values equal to 1.57 (statistically not significant) and 4.64 (statistically significant). However, for the Esperanza station, it determined a cooling trend for tmin and a slight non-significant warming for <em>t</em><sub>max</sub> with a <em>Z</em><sub><em>MK</em></sub> statistic of -2.27 (statistically significant) and 1.16 (statistically not significant), for a significance level <em>α</em> = 0.05.展开更多
Sea level rise has become an important issue in global climate change studies. This study investigates trends in sea level records, particularly extreme records, in the Pearl River Estuary, using measurements from two...Sea level rise has become an important issue in global climate change studies. This study investigates trends in sea level records, particularly extreme records, in the Pearl River Estuary, using measurements from two tide gauge stations in Macao and Hong Kong. Extremes in the original sea level records （daily higher high water heights） and in tidal residuals with and without the 18.6-year nodal modulation are investigated separately. Thresholds for defining extreme sea levels are calibrated based on extreme value theory. Extreme events are then modeled by peaks-over-threshold models. The model applied to extremes in original sea level records does not include modeling of their durations, while a geometric distribution is added to model the duration of extremes in tidal residuals. Realistic modeling results are recommended in all stationary models. Parametric trends of extreme sea level records are then introduced to nonstationary models through a generalized linear model framework. The result shows that, in recent decades, since the 1960s, no significant trends can be found in any type of extreme at any station, which may be related to a reduction in the influence of tropical cyclones in the region. For the longer-term record since the 1920s at Macao, a regime shift of tidal amplitudes around the 1970s may partially explain the diverse trend of extremes in original sea level records and tidal residuals.展开更多
Based on daily maximum and minimum temperatures at 18 meteorological stations in the Qilian Mountains and Hexi Corridor between 1960 and 2013,temporal and spatial variations in extreme temperatures were analysed using...Based on daily maximum and minimum temperatures at 18 meteorological stations in the Qilian Mountains and Hexi Corridor between 1960 and 2013,temporal and spatial variations in extreme temperatures were analysed using linear trends,tenpoint moving averages and the Mann-Kendall test.The results are as follows:The trends in the majority of the extreme temperature indices were statistically significant,and the changes in the extreme temperatures were more obvious than the changes in the extreme values.The trends were different for each season,and the changes in rates and intensities in summer and autumn were larger than those in spring and winter.Unlike the cold indices,the magnitudes and trends of the changes in the warm indices were larger and more significant in the Hexi Corridor than in the Qilian Mountains.Abrupt changes were detected in the majority of the extreme temperature indices,and the extreme cold indices usually occurred earlier than the changes in the extreme warm indices.The abrupt changes in the extreme temperatures in winter were the earliest among the four seasons,indicating that these temperature changes were the most sensitive to global climate change.The timing of the abrupt changes in certain indices was consistent throughout the study area,but the changes in the cold indices in the Hexi Corridor occurred approximately four years before those in the Qilian Mountains.Similarly,the changes in the warm indices in the western Hexi Corridor preceded those of the other regions.展开更多
The brokering approach can be successfully used to overcome the crucial question of searching among enormous amount of data （raw and/or processed） produced and stored in different information systems. In this paper,...The brokering approach can be successfully used to overcome the crucial question of searching among enormous amount of data （raw and/or processed） produced and stored in different information systems. In this paper, authors describe the Data Management System the DMS （Data Management System） developed by INGV （Istituto Nazionale di Geofisica e Vulcanologia） to support the brokering system GEOSS （Global Earth Observation System of Systems） adopted for the ARCA （Arctic Present Climate Change and Past Extreme Events） project. This DMS includes heterogeneous data that contributes to the ARCA objective （www.arcaproject.it） focusing on multi-parametric and multi-disciplinary studies on the mechanism （s） behind the release of large volumes of cold and fresh water from melting of ice caps. The DMS is accessible directly at the www.arca.rm.ingv.it, or through the IADC （Italian Arctic Data Center） at http：//arcticnode.dta.cnr.it/iadc/gi-portal/index.jsp that interoperates with the GEOSS brokering system （http：//www.geoportal.org0 making easy and fast the search of specific data set and its URL.展开更多
基金supported by the special climate change in 2010 of the China Meteorological Administration (No. ccfs-2010)the National Natural Science Foundation of China (No. 41275097)
文摘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.
基金supported by the Special Climate Change Research Program of China Meteorological Administration (No. CCSF-09-11, CCSF-09-03, CCSF2011-25, and CCSF201211)the Science and Technology Planning Project of Guangdong province (No.2011A030200021)
文摘Daily climate data at 110 stations during 1961-2010 were selected to examine the changing characteristics of climate factors and extreme climate events in South China. The annual mean surface air temperature has increased significantly by 0.16℃ per decade, most notably in the Pearl River Delta and in winter. The increase rate of the annual extreme minimum temperature (0.48℃ per decade) is over twice that of the annual extreme maximum temperature (0.20℃ per decade), and the increase of the mean temperature is mainly the result of the increase of the extreme minimum temperature. The increase rate of high-temperature days (1.1 d per decade) is close to the decrease rate of low-temperature days (-1.3 d per decade). The rainfall has not shown any significant trend, but the number of rainy days has decreased and the rain intensity has increased. The regional mean sunshine duration has a significant decreasing trend of -40.9 h per decade, and the number of hazy days has a significant increasing trend of 6.3 d per decade. The decrease of sunshine duration is mainly caused by the increase of total cloud, not by the increase of hazy days in South China. Both the regional mean pan evaporation and mean wind speed have significant decreasing trends of -65.9 mm per decade and -0.11 m s-1 per decade, respectively. The decrease of both sunshine duration and mean wind speed plays an important role in the decrease of pan evaporation. The number of landing tropical cyclones has an insignificant decreasing trend of -0.6 per decade, but their intensities show a weak increasing trend. The formation location of tropical cyclones landing in South China has converged towards 10-19°N, and the landing position has shown a northward trend. The date of the first landfall tropical cyclone postpones 1.8 d per decade, and the date of the last landfall advances 3.6 d per decade, resulting in reduction of the typhoon season by 5.4 d per decade.
基金funded by the Fundamental Research Funds for the Central Universities (Grant nos.2017B04814,2017B20714),Hohai UniversityState Key Laboratory of Satellite Ocean Environment Dynamics+1 种基金supported by the Global Change Research Program of China (Grant no.2015CB953904)the National Natural Science Foundation of China (NSFC,Grant no.41876220)
文摘Polar climate systems have experienced a number of dramatic changes （Wang et al., 2017; Turner et al., 2016; Gordon, 2014; Rignot et al., 2013; Meier et al., 2012; Kwok and Rothrock, 2009; Thompson and Solomon, 2002）, which have influenced climatic conditions across large parts of the globe through large-scale atmospheric and oceanic teleconnections （Dou and Wu, 2018; Zhang et al., 2018;
文摘The study area is located between the cities of Comitan (16°10'43"N and 92°04'20''W) a city with 150,000 inhabitants and La Esperanza (16°9'15''N and 91°52'5''W) a town with 3000 inhabitants. Both weather stations are 30 km from each other in the Chiapas State, México. 54 years of daily records of the series of maximum (<em>t</em><sub>max</sub>) and minimum temperatures (<em>t</em><sub>min</sub>) of the weather station 07205 Comitan that is on top of a house and 30 years of daily records of the weather station 07374 La Esperanza were analyzed. The objective is to analyze the evidence of climate change in the Comitan valley. 2.07% and 19.04% of missing data were filled, respectively, with the WS method. In order to verify homogeneity three methods were used: Standard Normal Homogeneity Test (SNHT), the Von Neumann method and the Buishand method. The heterogeneous series were homogenized using climatol. The trends of <em>t</em><sub>max</sub> and <em>t</em><sub>min</sub> for both weather stations were analyzed by simple linear regression, Sperman’s rho and Mann-Kendall tests. The Mann-Kendal test method confirmed the warming trend at the Comitan station for both variables with <em>Z<sub>MK</sub></em> statistic values equal to 1.57 (statistically not significant) and 4.64 (statistically significant). However, for the Esperanza station, it determined a cooling trend for tmin and a slight non-significant warming for <em>t</em><sub>max</sub> with a <em>Z</em><sub><em>MK</em></sub> statistic of -2.27 (statistically significant) and 1.16 (statistically not significant), for a significance level <em>α</em> = 0.05.
基金supported by the National Natural Science Foundation of China(Project No.41375096)the Research Grants Council of the Hong Kong Special Administrative Region(Project Nos.14408214 and 11305715)
文摘Sea level rise has become an important issue in global climate change studies. This study investigates trends in sea level records, particularly extreme records, in the Pearl River Estuary, using measurements from two tide gauge stations in Macao and Hong Kong. Extremes in the original sea level records （daily higher high water heights） and in tidal residuals with and without the 18.6-year nodal modulation are investigated separately. Thresholds for defining extreme sea levels are calibrated based on extreme value theory. Extreme events are then modeled by peaks-over-threshold models. The model applied to extremes in original sea level records does not include modeling of their durations, while a geometric distribution is added to model the duration of extremes in tidal residuals. Realistic modeling results are recommended in all stationary models. Parametric trends of extreme sea level records are then introduced to nonstationary models through a generalized linear model framework. The result shows that, in recent decades, since the 1960s, no significant trends can be found in any type of extreme at any station, which may be related to a reduction in the influence of tropical cyclones in the region. For the longer-term record since the 1920s at Macao, a regime shift of tidal amplitudes around the 1970s may partially explain the diverse trend of extremes in original sea level records and tidal residuals.
基金funded by the National Natural Science Foundation of China(No.41161017)National Natural Science Foundation of Gansu Province(No.1107RJZA248)
文摘Based on daily maximum and minimum temperatures at 18 meteorological stations in the Qilian Mountains and Hexi Corridor between 1960 and 2013,temporal and spatial variations in extreme temperatures were analysed using linear trends,tenpoint moving averages and the Mann-Kendall test.The results are as follows:The trends in the majority of the extreme temperature indices were statistically significant,and the changes in the extreme temperatures were more obvious than the changes in the extreme values.The trends were different for each season,and the changes in rates and intensities in summer and autumn were larger than those in spring and winter.Unlike the cold indices,the magnitudes and trends of the changes in the warm indices were larger and more significant in the Hexi Corridor than in the Qilian Mountains.Abrupt changes were detected in the majority of the extreme temperature indices,and the extreme cold indices usually occurred earlier than the changes in the extreme warm indices.The abrupt changes in the extreme temperatures in winter were the earliest among the four seasons,indicating that these temperature changes were the most sensitive to global climate change.The timing of the abrupt changes in certain indices was consistent throughout the study area,but the changes in the cold indices in the Hexi Corridor occurred approximately four years before those in the Qilian Mountains.Similarly,the changes in the warm indices in the western Hexi Corridor preceded those of the other regions.
文摘The brokering approach can be successfully used to overcome the crucial question of searching among enormous amount of data （raw and/or processed） produced and stored in different information systems. In this paper, authors describe the Data Management System the DMS （Data Management System） developed by INGV （Istituto Nazionale di Geofisica e Vulcanologia） to support the brokering system GEOSS （Global Earth Observation System of Systems） adopted for the ARCA （Arctic Present Climate Change and Past Extreme Events） project. This DMS includes heterogeneous data that contributes to the ARCA objective （www.arcaproject.it） focusing on multi-parametric and multi-disciplinary studies on the mechanism （s） behind the release of large volumes of cold and fresh water from melting of ice caps. The DMS is accessible directly at the www.arca.rm.ingv.it, or through the IADC （Italian Arctic Data Center） at http：//arcticnode.dta.cnr.it/iadc/gi-portal/index.jsp that interoperates with the GEOSS brokering system （http：//www.geoportal.org0 making easy and fast the search of specific data set and its URL.
