The sea level derived from TOPEX/Poseidon （T/P） altimetry data shows prominent long term trend and inter-annual variability. The global mean sea level rising rate during 1993-2003 was 2.9mm a^-1. The T/P sea level t...The sea level derived from TOPEX/Poseidon （T/P） altimetry data shows prominent long term trend and inter-annual variability. The global mean sea level rising rate during 1993-2003 was 2.9mm a^-1. The T/P sea level trend maps the geographical variability. In the Northern Hemisphere （15°-64°N）, the sea level rise is very fast at the mid-latitude （20°-40°N） but much slower at the high-latitude, for example, only 0.5 mm a^-1 in the latitude band 40°-50°N. In the Southern Hemisphere, the sea level shows high rising rate both in mid-latitude and high-latitude areas, for example, 5.1 mm a^-1 in the band 40°- 50°S. The global thermosteric sea level （TSL） derived from Ishii temperature data was rising during 1993-2003 at a rate of 1.2 mm a^-1 and accounted for more than 40% of the global T/P sea level rise. The contributions of the TSL distribution are not spatially uniform; for instance, the percentage is 67% for the Northern Hemisphere and only 29% for the Southern Hemisphere （15°-64°S） and the maximum thermosteric contribution appears in the Pacific Ocean, which contributes more than 60% of the global TSL. The sea level change trend in tropical ocean is mainly caused by the thermosteric effect, which is different from the case of seasonal variability in this area. The TSL variability dominates the T/P sea level rise in the North Atlantic, but it is small in other areas, and shows negative trend at the high-latitude area （40°-60°N, and 50°-60°S）. The global TSL during 1945-2003 showed obvious rising trend with the rate of about 0.3 mm a-l and striking inter-annual and decadal variability with period of 20 years. In the past 60 years, the Atlantic TSL was rising continuously and remarkably, contributing 38% to the global TSL rising. The TSL in the Pacific and Indian Ocean rose with significant in- ter-annual and decadal variability. The first EOF mode of the global TSL from Ishii temperature data was the ENSO mode in which the time series of the first mode showed steady rising trend. Among the three oceans, the first mode of the Pacific TSL presented the ENSO mode; there was relatively steady rising trend in the Atlantic Ocean, and no dominant mode in the Indian Ocean.展开更多
The impact of climate change on sea level has received a great deal of attention by scientists worldwide. In this context, the problem of sea levels on global and regional scales have been analyzed in a number of stud...The impact of climate change on sea level has received a great deal of attention by scientists worldwide. In this context, the problem of sea levels on global and regional scales have been analyzed in a number of studies based on tide gauges observations and satellite altimetry measurements. This study focuses on trend estimates from 18 high-quality tide gauge stations along the Mediterranean Sea coast. The seasonal Mann-Kendall test was run at a 5% significance level for each of the 18 stations for the period of 1993-2015 (satellite altimetry era). The results of this test indicate that the trends for 17 stations were statistically significant and showed an increase (no significant trend was observed only at one station). The rates of sea level change for the 17 stations that exhibit significant trends, estimated using seasonal Sen's approach, range after correction for Vertical Land Motion (VLM) from 1.48 to 8.72 mm/a for the period 1993-2015. Furthermore, the magnitude of change at the location of each tide gauge station was estimated using the satellite altimetry measurements. Thus, the results obtained agree with those from the tide-gauge data analysis.展开更多
The main purpose of this study is to highlight, on the basis of statistical tests, the significant long-term changes of the Mediterranean Sea level, through the analysis of historical tide gauge records. In this frame...The main purpose of this study is to highlight, on the basis of statistical tests, the significant long-term changes of the Mediterranean Sea level, through the analysis of historical tide gauge records. In this framework, 14 tide gauge monthly series selected from the Permanent Service of the Mean Sea Level(PSMSL) database were used. The search for the presence or not of trends within these series, that have a temporal coverage from 59 to 142 years, was carried out using the Mann-Kendall test and the Sen’s slope estimator. The obtained results show that the Split Rt Marjana series are the only ones which does not exhibit a significant trend. The other 13 series show significant increasing trends. This result seems sufficient to suppose the presence, in the past century, of a new climatic phase on the scale of the Mediterranean basin, where the rising sea level is one of the consequences.展开更多
On the basis of the analytical results of the period components of monthly mean sea level of 236 stationsin the Pacific, the period components plus linear trend are ed to fit the monthly mean sea level series. The sta...On the basis of the analytical results of the period components of monthly mean sea level of 236 stationsin the Pacific, the period components plus linear trend are ed to fit the monthly mean sea level series. The statisticalresults of linear trend Coefficients of these stations indicate that, if the abnormal values of sea-level rise and fall are neglected, the average rise rate of relative sea level in the Pacific is 1. 16 mm/a. Affected by nonuniformity Of land subsidence and other factors, the regional change of relative sea level rise or fall in the Pacific is greater. In the light of thepositive or negative values of linear trend coefficients as well as the geographical position of the sea area, zoning is madeof the sea level rise or fall in the Pacific including the coastal areas of China and Southeast Asia to obtain the averagerate of rise or fall in each sea area. The rise or fall trends of relative sea level obtained for the entire Pacific Ocean,west coast of North America, the northern and central South America, the greater part of the tropical Pacific and thecoastal Islands of Japan are basically in keeping with the other relevant results. The regional average estimated result ofthe relative sea level in the coast of East Asia is on the rise while the estimated results provided by Barnett tend todrop; the main cause of this nonuniformity is the number of stations selected and the distributional density.展开更多
In recent years, Senegal has been confronted with increasingly frequent and damaging extreme events. In the context of climate change, we conducted this study to characterize the trends of rainfall extremes in Senegal...In recent years, Senegal has been confronted with increasingly frequent and damaging extreme events. In the context of climate change, we conducted this study to characterize the trends of rainfall extremes in Senegal. In this work, we used daily rainfall data from 27 stations in Senegal from the period 1951 to 2005 (55 years). To study their linear trends, non-stationary extreme value models with time as a covariate are fitted to evaluate them. Our results indicate a decreasing trend of extreme rainfalls at most of the stations except for 5 stations. However, the decreasing trends are only significant for two stations (Thiès and Kidira), however, this can only be taken as information that climate change may have already impacted extreme rainfalls. For the 20-year and 30-year return periods, the results show that they have undergone changes, in fact for almost all stations, the trends in return periods are decreasing.展开更多
The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constan...The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constant production rate which stops attaining a desired level of inventories and that is the highest level of inventories. Production starts with a buffer stock and without any sort of backlogs. Due to the market demand and product’s decay, the inventory reduces to the level of buffer stock where again the production cycle starts. With a numerical search procedure the proof of the proposed model has been shown. The objective of the model is to obtain the total average optimum inventory cost and optimum ordering cycle.展开更多
Bangladesh is a south Asian Monsoonal Country and the recent precipitation pattern in the Cox’s Bazar area of Bangladesh is changing and increasing the number of monsoonal slope failures and landslide hazards in the ...Bangladesh is a south Asian Monsoonal Country and the recent precipitation pattern in the Cox’s Bazar area of Bangladesh is changing and increasing the number of monsoonal slope failures and landslide hazards in the Kutubpalong & Balukhali Rohingya camp area. An attempt has been made to see the influence of seasonal variation of ground water level (G.W.L.) fluctuations on the stability of the eco hills and forests of Ukhiya Teknaf region. Ukhiya hills are in great danger because of cutting trees from the hill slopes and it is well established that due to recent change of climate, short term rainfall for few consecutive days during monsoon might show an influence on the factor of safety (Fs) values of the camp hill slopes. A clear G.W.L. variation between dry and wet seasons has an influence on the stability (Fs) values indicating that climate has a strong influence on the stability and threatening sustainable development. A stable or marginally stable slope might be unstable during raining and show a variation of ground water level (G.W.L.). The generation of pore water pressure (P.W.P.) is also influenced by seasonal variation of ground water level. During wet season negative P.W.P. called suction plays an important role to occur slope failures in the Ukhiya hills. Based on all calculated factor of safety values (Fs) at different locations, four (4) susceptible landslide risk zones are identified. They are very high risk (Fs = 0.18 to 0.46), high risk (Fs = 0.56 to 0.75), medium risk (Fs = 0.76 to 1.0) and marginally stable areas (Fs ≈ 1). Proper geo-engineering measures must be taken by the concerned authorizes to reduce P.W.P. during monsoon by installing rain water harvesting system, allowing sufficient drainage & other geotechnical measures to reduce the risk of slope failures in the Ukhiya hills. Based on the stability factor (Fs) at different slope locations of the camp hills, a risk map of the investigated area has been produced for the local community for their safety and to build up awareness & to motivate them to evacuate the site during monsoonal slope failures. The established “Risk Maps” can be used for future geological engineering works as well as for sustainable planning, design and construction purposes relating to adaptation and mitigation of landslide risks in the investigated area.展开更多
基金supported by the National Basic Research Program of China (No 2007CB411807)the NSFC project (Nos 40976006 and 40906002)+1 种基金the National Key Technology R&D Program (No 2007BAC03A06-06)the project of Key Laboratory of Coastal Disasters and Defence (No 200802)
文摘The sea level derived from TOPEX/Poseidon （T/P） altimetry data shows prominent long term trend and inter-annual variability. The global mean sea level rising rate during 1993-2003 was 2.9mm a^-1. The T/P sea level trend maps the geographical variability. In the Northern Hemisphere （15°-64°N）, the sea level rise is very fast at the mid-latitude （20°-40°N） but much slower at the high-latitude, for example, only 0.5 mm a^-1 in the latitude band 40°-50°N. In the Southern Hemisphere, the sea level shows high rising rate both in mid-latitude and high-latitude areas, for example, 5.1 mm a^-1 in the band 40°- 50°S. The global thermosteric sea level （TSL） derived from Ishii temperature data was rising during 1993-2003 at a rate of 1.2 mm a^-1 and accounted for more than 40% of the global T/P sea level rise. The contributions of the TSL distribution are not spatially uniform; for instance, the percentage is 67% for the Northern Hemisphere and only 29% for the Southern Hemisphere （15°-64°S） and the maximum thermosteric contribution appears in the Pacific Ocean, which contributes more than 60% of the global TSL. The sea level change trend in tropical ocean is mainly caused by the thermosteric effect, which is different from the case of seasonal variability in this area. The TSL variability dominates the T/P sea level rise in the North Atlantic, but it is small in other areas, and shows negative trend at the high-latitude area （40°-60°N, and 50°-60°S）. The global TSL during 1945-2003 showed obvious rising trend with the rate of about 0.3 mm a-l and striking inter-annual and decadal variability with period of 20 years. In the past 60 years, the Atlantic TSL was rising continuously and remarkably, contributing 38% to the global TSL rising. The TSL in the Pacific and Indian Ocean rose with significant in- ter-annual and decadal variability. The first EOF mode of the global TSL from Ishii temperature data was the ENSO mode in which the time series of the first mode showed steady rising trend. Among the three oceans, the first mode of the Pacific TSL presented the ENSO mode; there was relatively steady rising trend in the Atlantic Ocean, and no dominant mode in the Indian Ocean.
文摘The impact of climate change on sea level has received a great deal of attention by scientists worldwide. In this context, the problem of sea levels on global and regional scales have been analyzed in a number of studies based on tide gauges observations and satellite altimetry measurements. This study focuses on trend estimates from 18 high-quality tide gauge stations along the Mediterranean Sea coast. The seasonal Mann-Kendall test was run at a 5% significance level for each of the 18 stations for the period of 1993-2015 (satellite altimetry era). The results of this test indicate that the trends for 17 stations were statistically significant and showed an increase (no significant trend was observed only at one station). The rates of sea level change for the 17 stations that exhibit significant trends, estimated using seasonal Sen's approach, range after correction for Vertical Land Motion (VLM) from 1.48 to 8.72 mm/a for the period 1993-2015. Furthermore, the magnitude of change at the location of each tide gauge station was estimated using the satellite altimetry measurements. Thus, the results obtained agree with those from the tide-gauge data analysis.
文摘The main purpose of this study is to highlight, on the basis of statistical tests, the significant long-term changes of the Mediterranean Sea level, through the analysis of historical tide gauge records. In this framework, 14 tide gauge monthly series selected from the Permanent Service of the Mean Sea Level(PSMSL) database were used. The search for the presence or not of trends within these series, that have a temporal coverage from 59 to 142 years, was carried out using the Mann-Kendall test and the Sen’s slope estimator. The obtained results show that the Split Rt Marjana series are the only ones which does not exhibit a significant trend. The other 13 series show significant increasing trends. This result seems sufficient to suppose the presence, in the past century, of a new climatic phase on the scale of the Mediterranean basin, where the rising sea level is one of the consequences.
文摘On the basis of the analytical results of the period components of monthly mean sea level of 236 stationsin the Pacific, the period components plus linear trend are ed to fit the monthly mean sea level series. The statisticalresults of linear trend Coefficients of these stations indicate that, if the abnormal values of sea-level rise and fall are neglected, the average rise rate of relative sea level in the Pacific is 1. 16 mm/a. Affected by nonuniformity Of land subsidence and other factors, the regional change of relative sea level rise or fall in the Pacific is greater. In the light of thepositive or negative values of linear trend coefficients as well as the geographical position of the sea area, zoning is madeof the sea level rise or fall in the Pacific including the coastal areas of China and Southeast Asia to obtain the averagerate of rise or fall in each sea area. The rise or fall trends of relative sea level obtained for the entire Pacific Ocean,west coast of North America, the northern and central South America, the greater part of the tropical Pacific and thecoastal Islands of Japan are basically in keeping with the other relevant results. The regional average estimated result ofthe relative sea level in the coast of East Asia is on the rise while the estimated results provided by Barnett tend todrop; the main cause of this nonuniformity is the number of stations selected and the distributional density.
文摘In recent years, Senegal has been confronted with increasingly frequent and damaging extreme events. In the context of climate change, we conducted this study to characterize the trends of rainfall extremes in Senegal. In this work, we used daily rainfall data from 27 stations in Senegal from the period 1951 to 2005 (55 years). To study their linear trends, non-stationary extreme value models with time as a covariate are fitted to evaluate them. Our results indicate a decreasing trend of extreme rainfalls at most of the stations except for 5 stations. However, the decreasing trends are only significant for two stations (Thiès and Kidira), however, this can only be taken as information that climate change may have already impacted extreme rainfalls. For the 20-year and 30-year return periods, the results show that they have undergone changes, in fact for almost all stations, the trends in return periods are decreasing.
文摘The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constant production rate which stops attaining a desired level of inventories and that is the highest level of inventories. Production starts with a buffer stock and without any sort of backlogs. Due to the market demand and product’s decay, the inventory reduces to the level of buffer stock where again the production cycle starts. With a numerical search procedure the proof of the proposed model has been shown. The objective of the model is to obtain the total average optimum inventory cost and optimum ordering cycle.
文摘Bangladesh is a south Asian Monsoonal Country and the recent precipitation pattern in the Cox’s Bazar area of Bangladesh is changing and increasing the number of monsoonal slope failures and landslide hazards in the Kutubpalong & Balukhali Rohingya camp area. An attempt has been made to see the influence of seasonal variation of ground water level (G.W.L.) fluctuations on the stability of the eco hills and forests of Ukhiya Teknaf region. Ukhiya hills are in great danger because of cutting trees from the hill slopes and it is well established that due to recent change of climate, short term rainfall for few consecutive days during monsoon might show an influence on the factor of safety (Fs) values of the camp hill slopes. A clear G.W.L. variation between dry and wet seasons has an influence on the stability (Fs) values indicating that climate has a strong influence on the stability and threatening sustainable development. A stable or marginally stable slope might be unstable during raining and show a variation of ground water level (G.W.L.). The generation of pore water pressure (P.W.P.) is also influenced by seasonal variation of ground water level. During wet season negative P.W.P. called suction plays an important role to occur slope failures in the Ukhiya hills. Based on all calculated factor of safety values (Fs) at different locations, four (4) susceptible landslide risk zones are identified. They are very high risk (Fs = 0.18 to 0.46), high risk (Fs = 0.56 to 0.75), medium risk (Fs = 0.76 to 1.0) and marginally stable areas (Fs ≈ 1). Proper geo-engineering measures must be taken by the concerned authorizes to reduce P.W.P. during monsoon by installing rain water harvesting system, allowing sufficient drainage & other geotechnical measures to reduce the risk of slope failures in the Ukhiya hills. Based on the stability factor (Fs) at different slope locations of the camp hills, a risk map of the investigated area has been produced for the local community for their safety and to build up awareness & to motivate them to evacuate the site during monsoonal slope failures. The established “Risk Maps” can be used for future geological engineering works as well as for sustainable planning, design and construction purposes relating to adaptation and mitigation of landslide risks in the investigated area.
