基于GAMLSS模型的辽西地区气候变化对暴雨洪水极值影响评估

文章基于GAMLSS(非一致性水文极值序列频率分析)模型,以辽西叶柏寿、司屯流域为例,分析气候变化对流域暴雨洪水极值序列的影响。结果表明:年最大降雨量序列受气候变化因子影响较为显著,与时间依赖性不高。人类活动对气候变化因子和年最大流量的相关性产生了显著影响,气候因子与年最大流量序列相关特征较为复杂。

人类活动和气候变化对石羊河流域水资源的影响——基于主客观综合赋权分析法

人类活动和气候变化对水资源的影响已为众多科学家关注。二者的影响谁起主导作用,贡献率究竟有多大,这是本文研究的重点。本文采用基于"功能驱动"原理的主观赋权法和基于"差异驱动"原理的客观赋权法,计算出了人类活动和气候变化对水资源影响的贡献率,最终采用综合集成赋权法计算了二者的权重系数。结果表明:①气候变化和人类活动对石羊河流域水资源的影响权重系数分别为52.63%和47.36%,这表明气候变化因子对水资源的影响要大于人类活动因子对水资源的影响;②气候变化对水资源的影响在流域内部存在差异,其主要表现在:中游地区的气候因子对水资源的贡献率最大,是区域内水资源对气候变化最真实的反映;上游地区由于积雪的消融和积累过程使得气候因子的贡献率较小;下游地区受降水效率和可供蒸发水量的限制贡献率也较小。

Changes of Dry-wet Climate in the Dry Season in Yunnan(1961-2007)

Factor analysis was used to investigate the changes of dry-wet climate in the dry season in Yunnan during 1961-2007 based on observed data from 15 stations.Three common factors were extracted from the 9 climatic factors.The results showed that the dry-wet climate has evidently changed since the early 1960s.The general trends in the changes of drywet climate were described as slight decrease in humidity and gradual enhancement in drought intensity.The climate during 1960s-1980s was under weak-medium drought.But since early 1990s,dry conditions have markedly strengthened and continued due to uneven temporal distribution of rainfall and climate warming.

Spatio-temporal Distribution Pattern of Vegetation Net Primary Productivity and Its Response to Climate Change in Buryatiya Republic,Russia

As a critical index for monitoring the response of terrestrial ecosystems to climate change, net primary productivity （NPP） is widely used to reflect the vegetation productivity under natural conditions. However, little is known about vegetation NPP in Buryatiya Republic, Russia. To fully understand temporal and spatial variations in vegetation NPP and its response to climate change, satellite images of Moderate-resolution Imaging Spectroradiometer （MODIS） Normalized Difference Vegetation Index （NDVI） products in conjunction with ground-based observations of climatology were used to estimate vegetation NPP in Buryatiya Republic from 2000 to 2008. Observed values of vegetation NPP and MODIS NPP products were jointly utilized to verify simulations of vegetation NPP in this area. The Carnegie Ames Stanford Approach （CASA） model was improved by adjusting its parameters with bio-temperature instead of monthly average temperature in a sub-model of soil water content. Model reliability was tested with observed vegetation NPP. Variation in vegetation NPP, and its relationship with climatic factors, was analyzed in detail. Results showed that the modified CASA model can be used to estimate vegetation NPP in Buryatiya Republic, and that the accuracy of the model was generally high with a correlation coefficient of 0.91 （P0.01）. The vegetation average annual NPP was 542.45 g C m^-2 y^ -1 and the total NPP was estimated as 1.91E＋14 g C y^ -1 from 2000 to 2008. Monthly vegetation NPP increased significantly from April to July, decreased rapidly from August to November, and remained steady from December to March of the next year. Vegetation NPP increased with increasing longitude and decreased with increasing latitude. Different vegetation types differ in total NPP, with the highest NPP in forests, followed by forest-steppe, high mountain vegetation, steppe and meadow-swamp. Temperature and precipitation were the primary factors limiting vegetation NPP in this area.

A Review on the Driving Mechanisms of Ecosystem Services Change

Ecosystem services have rapidly changed at the global and regional scales in recent years. Exploring the driving mechanisms of ecosystem services change and projecting future change are of increasing importance to inform policy and decision-making options for ecosystem conservation and sustainable use. Although some research has analyzed the influences of land use or climate changes on ecosystem services, a systematic review on the mechanisms of ecosystem services change has not been carried out so far. This work elaborated on the mechanisms of ecosystem services change based on a literature review, and reached four main conclusions.(1)Climate change and land use jointly determine the ecosystem services change through complex and interacting pathways.(2) Whereas the present research progresses mainly focus on the identification of a single influencing factor, they fail in the determination of multiple influencing factors.(3) Although multi-scenario simulations based on remote sensing and climate models are the main means used to predict future changes in ecosystem services,clarifying the interactive mechanisms of multiple factors is the precondition for future projection of ecosystem services change;(4) Therefore, future research should strengthen the analysis and simulation of the effects of human activities on ecosystem services, especially the development of technology to detect the dynamic responses of ecosystem services to major ecological projects, which is crucial to the selection of restoration measures and the regional arrangement of ecosystem conservation projects.

The state and fate of lake ice thickness in the Northern Hemisphere

Lake ice thickness(LIT)is important for regional hydroclimate systems,lake ecosystems,and human activities on the ice,and is thought to be highly susceptible to global warming.However,the spatiotemporal variability in LIT is largely unknown due to the difficulty in deriving in situ measurements and the lack of an effective remote sensing platform.Despite intensive development and applications of lake ice models driven by general circulation model output,evaluation of the global LIT is mostly based on assumed“ideal”lakes in each grid cell of the climate forcing data.A method for calculating the actual global LIT is therefore urgently needed.Here we use satellite altimetry to retrieve ice thickness for 16 large lakes in the Northern Hemisphere(Lake Baikal,Great Slave Lake,and others)with an accuracy of~0.2 m for almost three decades.We then develop a 1-D lake ice model driven primarily by remotely sensed data and cross-validated with the altimetric LIT to provide a robust means of estimating LIT for lakes larger than 50 km^(2)across the Northern Hemisphere.Mean LIT(annual maximum ice thickness)for 1313 simulated lakes and reservoirs covering~840,000 km^(2)for 2003–2018 is 0.63±0.02 m,corresponding to~485 Gt of water.LIT changes are projected for 2071–2099 under RCPs 2.6,6.0,and 8.5,showing that the mean LIT could decrease by~0.35 m under the worst concentration pathway and the associated lower ice road availability could have a significant impact on socio-economic activities.

Association Between Himalayan Marmot Density and Climatic Factor

Objective:This study aims to explore the association between the density of Himalayan marmot (Marmota himalayana) and climatic factors such as temperature, precipitation, humidity, vapour pressure, sunshine percentage, wind velocity, which are closely associated with global climate change, and to provide a reference for plague prevention and control. Methods: We conducted a regression analysis to find the possible climate factors associated with the density of Himalaya marmot, and analyzed the response characters of Himalayan marmot to climate change.Results: Dailyprecipitation days(>=0.1 mm) and sunshine percentage were significantly associated with thedensityofHimalayan marmot(p<0.01). Conclusion: Climate change was associated with the risk of plague. This phenomenon is valuable for Himalayan marmot and plague prevention. More studies are needed to understand the impact of climate change on Himalayan marmot and plague.