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101.
The temperature appeared rising trend during the 20th century in China's tropics.Two cooling stages and two warming stages in the process of climatic fluctuation can be recognized.After the 1980s the climate is the warmest which corresponds to the global change,but the warmest period is the 1940s in Kunming.The climate pattern mostly appears contemporaneity of warming and humidity,which is different from the situation of whole China.The natural disasters tend to be aggravated.The number of typhoons increased.Flood damages occurred frequently in the years of more typhoons.The number of droughts and cold damages increased.It was snowed in Guangzhou.There was frost in Haikou and Yaxian.Four years of heavy snow have been recorded in Kunming. 相似文献
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随着我国机构改革的不断深入和社会主义市场经济体制的逐步建立和完善,地震学会同其他社会团体一样将成为现代社会的支柱之一。以山西省地震学会目前的工作现状为例,指出学会在管理体制、运行机制和活动方式等方面存在的问题,提出了发展思路及建议。 相似文献
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0前言中国是一个多地震国家,频繁而严重的地震灾害给人民生命和财产带来了巨大的损失,防震减灾任务任重而道远。回良玉副总理2004年在全国防震减灾工作会议讲话中指出:“防震减灾是全社会共同的责任,要广泛动员社会各方的力量,积极投入到这项事业中来,使防震减灾逐步成为全社会的自觉行动。”因此,总结近40年我国防震减灾工作和改革开放的实践经验,对社会公众进行各种防震减灾宣传教育,广泛动员全社会力量,建立健全防震减灾社会动员机制,增强全社会防震减灾意识,是提高我国综合防震减灾能力,有效地促进地震灾害综合防御各项措施落实的重要途… 相似文献
106.
我国地震海浪初步分析 总被引:1,自引:0,他引:1
总结了我国地震海浪的25次记录,在做初步分析后认为我国的地震海浪多由近海海洋地震引起,其多发地区为渤海沿岸与东南沿海一带.随着对沿海地区开发的深入,这类记载逐渐增多,受灾程度加大.另外分析了在社会历史变迁中,国家对海洋的开发政策、沿海开发下城市近海地理位置、沿海港口及海洋贸易的规模与地震海浪受灾程度之间的关系. 相似文献
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In this study, the climate teleconnections with meteorological droughts are analysed and used to develop ensemble drought prediction models using a support vector machine (SVM)–copula approach over Western Rajasthan (India). The meteorological droughts are identified using the Standardized Precipitation Index (SPI). In the analysis of large‐scale climate forcing represented by climate indices such as El Niño Southern Oscillation, Indian Ocean Dipole Mode and Atlantic Multidecadal Oscillation on regional droughts, it is found that regional droughts exhibits interannual as well as interdecadal variability. On the basis of potential teleconnections between regional droughts and climate indices, SPI‐based drought forecasting models are developed with up to 3 months' lead time. As traditional statistical forecast models are unable to capture nonlinearity and nonstationarity associated with drought forecasts, a machine learning technique, namely, support vector regression (SVR), is adopted to forecast the drought index, and the copula method is used to model the joint distribution of observed and predicted drought index. The copula‐based conditional distribution of an observed drought index conditioned on predicted drought index is utilized to simulate ensembles of drought forecasts. Two variants of drought forecast models are developed, namely a single model for all the periods in a year and separate models for each of the four seasons in a year. The performance of developed models is validated for predicting drought time series for 10 years' data. Improvement in ensemble prediction of drought indices is observed for combined seasonal model over the single model without seasonal partitions. The results show that the proposed SVM–copula approach improves the drought prediction capability and provides estimation of uncertainty associated with drought predictions. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
109.
Likely effects of climate change on groundwater availability in a Mediterranean region of Southeastern Spain
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Hassane Moutahir Pau Bellot Robert Monjo Juan Bellot Miguel Garcia Issam Touhami 《水文研究》2017,31(1):161-176
Groundwater resources are typically the main fresh water source in arid and semi‐arid regions. Natural recharge of aquifers is mainly based on precipitation; however, only heavy precipitation events (HPEs) are expected to produce appreciable aquifer recharge in these environments. In this work, we used daily precipitation and monthly water level time series from different locations over a Mediterranean region of Southeastern Spain to identify the critical threshold value to define HPEs that lead to appreciable aquifer recharge in this region. Wavelet and trend analyses were used to study the changes in the temporal distribution of the chosen HPEs (≥20 mm day?1) over the observed period 1953–2012 and its projected evolution by using 18 downscaled climate projections over the projected period 2040–2099. The used precipitation time series were grouped in 10 clusters according to similarities between them assessed by using Pearson correlations. Results showed that the critical HPE threshold for the study area is 20 mm day?1. Wavelet analysis showed that observed significant seasonal and annual peaks in global wavelet spectrum in the first sub‐period (1953–1982) are no longer significant in the second sub‐period (1983–2012) in the major part of the ten clusters. This change is because of the reduction of the mean HPEs number, which showed a negative trend over the observed period in nine clusters and was significant in five of them. However, the mean size of HPEs showed a positive trend in six clusters. A similar tendency of change is expected over the projected period. The expected reduction of the mean HPEs number is two times higher under the high climate scenario (RCP8.5) than under the moderate scenario (RCP4.5). The mean size of these events is expected to increase under the two scenarios. The groundwater availability will be affected by the reduction of HPE number which will increase the length of no aquifer recharge periods (NARP) accentuating the groundwater drought in the region. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
110.
Accepting the concept of standardization introduced by the standardized precipitation index, similar methodologies have been developed to construct some other standardized drought indices such as the standardized precipitation evapotranspiration index (SPEI). In this study, the authors provided deep insight into the SPEI and recognized potential deficiencies/limitations in relating to the climatic water balance it used. By coupling another well‐known Palmer drought severity index (PDSI), we proposed a new standardized Palmer drought index (SPDI) through a moisture departure probabilistic approach, which allows multi‐scalar calculation for accurate temporal and spatial comparison of the hydro‐meteorological conditions of different locations. Using datasets of monthly precipitation, temperature and soil available water capacity, the moisture deficit/surplus was calculated at multiple temporal scales, and a couple of techniques were adopted to adjust corresponding time series to a generalized extreme value distribution out of several candidates. Results of the historical records (1900–2012) for diverse climates by multiple indices showed that the SPDI was highly consistent and correlated with the SPEI and self‐calibrated PDSI at most analysed time scales. Furthermore, a simple experiment of hypothetical temperature and/or precipitation change scenarios also verified the effectiveness of this newly derived SPDI in response to climate change impacts. Being more robust and preferable in spatial consistency and comparability as well as combining the simplicity of calculation with sufficient accounting of the physical nature of water supply and demand relating to droughts, the SPDI is promising to serve as a competent reference and an alternative for drought assessment and monitoring. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献