Accounting for the solar radiation in thermal regime prediction for railway subgrade in cold regions

This paper presents a comparative analysis of simulation processes of seasonal freezing-thawing of railway subgrade and permafrost degradation, with and without accounting for solar radiation. Also, the effect of sun screens to reduce the degradation of subgrade permafrost under different climatic conditions is numerically substantiated. And finally, the temperature criterion of the origination of permafrost is illustrated.     

Global rain-fed,irrigated, and paddy croplands: A new high resolution map derived from remote sensing,crop inventories and climate data

Irrigation accounts for 70% of global water use by humans and 33–40% of global food production comes from irrigated croplands. Accurate and timely information related to global irrigation is therefore needed to manage increasingly scarce water resources and to improve food security in the face of yield gaps, climate change and extreme events such as droughts, floods, and heat waves. Unfortunately, this information is not available for many regions of the world. This study aims to improve characterization of global rain-fed, irrigated and paddy croplands by integrating information from national and sub-national surveys, remote sensing, and gridded climate data sets. To achieve this goal, we used supervised classification of remote sensing, climate, and agricultural inventory data to generate a global map of irrigated, rain-fed, and paddy croplands. We estimate that 314 million hectares (Mha) worldwide were irrigated circa 2005. This includes 66 Mha of irrigated paddy cropland and 249 Mha of irrigated non-paddy cropland. Additionally, we estimate that 1047 Mha of cropland are managed under rain-fed conditions, including 63 Mha of rain-fed paddy cropland and 985 Mha of rain-fed non-paddy cropland. More generally, our results show that global mapping of irrigated, rain-fed, and paddy croplands is possible by combining information from multiple data sources. However, regions with rapidly changing irrigation or complex mixtures of irrigated and non-irrigated crops present significant challenges and require more and better data to support high quality mapping of irrigation.     

Developing markets for water reallocation: Revisiting the experience of Spanish water mercantilización

Economic instruments are being promoted as a desirable alternative to public sector action in the allocation and management of natural resources. A wide body of literature has developed that critically analyzes this phenomenon as part of a wider project of ‘neoliberalization of nature’, trying to uncover the underlying rationale and commonalities of geographically specific phenomena. The case of water is at the vanguard of these processes and is proving to be particularly contentious. In the European Union water policies are increasingly emphasizing the application of economic instruments to improve the allocative equity and economic efficiency in the use of scarce resources. However, there are few analyses of how these instruments are really working on the ground and whether they are meeting their objectives. This paper aims to contribute to this debate by critically analyzing the experience with water markets in Spain, the only country in the European Union where they are operative. It looks at water permit sales during the 2005–2008 drought period using the Tajo–Segura transfer infrastructure. The paper describes how the institutional process of mercantilización of water works in practice in Spain. It shows that the use of markets requires an intense process of institutional development to facilitate and encourage their operation. These institutions tend to favor the interests of clearly identifiable elites, instead of the public interest they supposedly promote.     

Old Chico’s new tricks: Neoliberalization and water sector reform in Brazil’s São Francisco River Basin

This article examines changing water governance modalities in the context of the neoliberalization of nature. Specifically, it focuses on Brazilian water sector reforms passed in 1997 that mandate decentralized and participatory decision-making at the river basin scale. Critics have suggested that rescaling, decentralization, and participatory governance mechanisms – supposedly intended to render decision-making more equitable, accessible, and relevant – can serve to legitimate, facilitate, and thus further embed processes of neoliberalization. Examining the impact of Brazil’s water sector reforms on the state–society relationship, this article presents a case study of water governance in the São Francisco River Basin and finds that the reforms – despite their neoliberalizing potential – have not significantly contributed to the neoliberalization of governance therein. Instead, water governance continues to be characterized by longstanding patterns of traditional elite control. Through an institutional and socio-natural analysis, this article describes and accounts for the continued dominance of these patterns relative to neoliberalization and explores activists’ efforts to use water sector reforms to pursue more progressive possibilities. The article concludes with a discussion of the implications for variegation and contestation in ongoing debates over neoliberal natures.     

Grassroots scalar politics: Insights from peasant water struggles in the Ecuadorian and Peruvian Andes

Based on insights from peasant and indigenous communities’ struggles for water in Andean Peru and Ecuador, in this article we argue that the defense of grassroots interests -and with it the advancement of more equitable governance- greatly hinges on the capacity of these groups to engage in grassroots scalar politics. With increasing pressure on water resources in the Andes, the access to water of many rural peasant and indigenous communities is being threatened. The growing realization that their access to water and related interests are embedded in broader regional and national politics, legal frameworks and water policies, has led many communities and peasant water user associations to engage in networks and create alliances with other water users, governmental institutions and non-governmental actors. To better understand these (and other) grassroots struggles and strategies, in this contribution we develop the concept of grassroots scalar politics, which we use as a lens to analyze two case studies. In Ecuador we present how water users of the province of Chimborazo have defended their interests through the consolidation of the Provincial Water Users Associations’ Federation Interjuntas-Chimborazo and its networks. Then we focus on how with the support of Interjuntas-Chimborazo the Water Users Association of the Chambo irrigation system defended their historical water allocation. In Peru we analyze the conformation and achievements of the federative Water Users Association of Ayacucho (JUDRA) and present how the community of Ccharhuancho in the region of Huancavelica, managed to defend its waters and territory against the coastal irrigation sector of Ica.     

Country-specific dietary shifts to mitigate climate and water crises

Undernutrition, obesity, climate change, and freshwater depletion share food and agricultural systems as an underlying driver. Efforts to more closely align dietary patterns with sustainability and health goals could be better informed with data covering the spectrum of countries characterized by over- and undernutrition. Here, we model the greenhouse gas (GHG) and water footprints of nine increasingly plant-forward diets, aligned with criteria for a healthy diet, specific to 140 countries. Results varied widely by country due to differences in: nutritional adjustments, baseline consumption patterns from which modeled diets were derived, import patterns, and the GHG- and water-intensities of foods by country of origin. Relative to exclusively plant-based (vegan) diets, diets comprised of plant foods with modest amounts of low-food chain animals (i.e., forage fish, bivalve mollusks, insects) had comparably small GHG and water footprints. In 95 percent of countries, diets that only included animal products for one meal per day were less GHG-intensive than lacto-ovo vegetarian diets (in which terrestrial and aquatic meats were eliminated entirely) in part due to the GHG-intensity of dairy foods. The relatively optimal choices among modeled diets otherwise varied across countries, in part due to contributions from deforestation (e.g., for feed production and grazing lands) and highly freshwater-intensive forms of aquaculture. Globally, modest plant-forward shifts (e.g., to low red meat diets) were offset by modeled increases in protein and caloric intake among undernourished populations, resulting in net increases in GHG and water footprints. These and other findings highlight the importance of trade, culture, and nutrition in diet footprint analyses. The country-specific results presented here could provide nutritionally-viable pathways for high-meat consuming countries as well as transitioning countries that might otherwise adopt the Western dietary pattern.     

From Bullets to Boreholes: A Disaggregated Analysis of Domestic Water Cooperation in Drought-prone Regions

Does water shortage incentivize cooperation? Case studies suggests that water scarcity can rarely, if at all, explain violence, instead such shortages rather facilitate cooperative actions around water. Another major argument from qualitative research holds that water scarcity and armed conflict often occur side by side. These insights have rarely been tested empirically across cases on a sub-national level. Earlier quantitative work instead focused on basin or state level interactions. This article fills these gaps by using disaggregated data to analyze the effect of water scarcity on incidences of domestic water cooperation. Using event data covering the Mediterranean area and Northern Africa (1997–2009), this article first shows that water-related actions, cooperative or conflictual, in general are more frequent in water scarce areas. Second, the analysis demonstrates that water cooperation occurs in areas with difficult access to groundwater and with a history of violence. Third, the findings suggest that the relationship between water scarcity and water cooperation is conditional on levels of democracy. The presented results also differ depending on whether state or non-state actors collaborate in domestic water initiatives. Taken together, these findings provide crucial insights to our understanding of environmental peacebuilding and water security.     

Estimating the global potential of water harvesting from successful case studies

Water harvesting has been widely applied in different social-ecological contexts, proving to be a valuable approach to sustainable intensification of agriculture. Global estimates of the potential of water harvesting are generally based on purely biophysical assessments and mostly neglect the socioeconomic dimension of agriculture. This neglect becomes a critical factor for the feasibility and effectiveness of policy and funding efforts to mainstream this practice. This study uses archetype analysis to systematically identify social-ecological regions worldwide based on >160 successful cases of local water harvesting implementation. We delineate six archetypal regions which capture the specific social-ecological conditions of the case studies. The archetypes cover 19% of current global croplands with hotspots in large portions of East Africa and Southeast Asia. We estimate that the adoption of water harvesting in these cropland areas can increase crop production up to 60–100% in Uganda, Burundi, Tanzania and India. The results of this study can complement conventional biophysical analysis on the potential of these practices and guide policy development at global and regional scales. The methodological approach can be also replicated at finer scales to guide the improvement of rainfed agricultural.     

局地蒸发和外部水汽输送对松花江流域夏季降水的贡献

本文基于Brubaker二元模型,采用JRA-55再分析资料定量研究了局地蒸发和外部水汽输送对松花江流域夏季气候态降水及其年际变率的相对贡献,并探讨了相应的物理机制。气候平均而言,外部水汽输送是松花江流域初夏（5～6月）和盛夏（7～8月）降水的最主要水汽源。受西风带影响,初夏自西边界进入松花江流域的水汽贡献占主导,外部水汽输送对当地降水的贡献为78.9%,源自蒸发的水汽贡献为21.1%。较之初夏,由于盛夏来自南边界的水汽输送加倍,外部水汽输送贡献增加,外部水汽输送和蒸发对降水贡献分别为86%和14%。JRA-55再分析资料可以合理再现观测降水演变,1961～2016年JRA-55再分析资料降水与观测在初夏与盛夏的相关系数分别可以达到0.73和0.83。研究发现,初夏,由于西南季风异常导致的南边界进入的水汽输送异常是松花江流域降水年际变率的主要原因,自西边界、北边界进入的水汽输送与降水呈现显著负相关,初夏局地蒸发的贡献不显著,该水汽输送异常对应的环流型易发生在El Ni?o衰减年初夏。盛夏来自南边界的水汽输送起主导作用,局地蒸发贡献与降水变化显著负相关,海温强迫作用对该环流异常的强迫并不显著,中高纬度大气内部变率影响占主导。由于盛夏降水与地表温度在盛夏期间显著负相关,盛夏时期降水偏少时,温度偏高,蒸发偏强,进而蒸发水汽对降水贡献增加。     

2017年“海棠”台风影响辽宁不同区域极端暴雨成因分析

利用常规观测、NCEP FNL、葵花8号卫星、GNSS反演大气可降水量、智能网格实况产品等资料,分析2017年“海棠”台风造成辽宁西部朝阳地区和东南部岫岩县的极端暴雨成因。结果表明：辽宁西部和东南半岛均出现区域性的极端特大暴雨,岫岩县小时雨强更大,最大雨强达到113 mm·h^-1,对流性降水特征明显。两个区域暴雨过程均受到热带、副热带、西风带系统共同作用,狭长型“海棠”台风沿着副热带高压西侧逐渐北上,并且与西风带短波槽相互作用,导致辽宁西部出现强降水,随后加强的涡旋系统后侧干冷空气与低空暖湿水汽输送带相互作用,导致岫岩县出现极端暴雨过程。热带台风“奥鹿”对副热带高压南落东退起到阻挡作用。两个区域均具有来自于南海的水汽通道,另外东南半岛也受到了“奥鹿”台风北侧水汽输送的影响。朝阳市和岫岩县大气可降水量值长时间接近65 mm和70 mm,异常指数最高达到3.0和2.5,表明此次暴雨水汽条件的极端性。辽宁西部降水期间动力不稳定更强,辐合层由地面伸展到500 hPa,而东南半岛降水期间上干下湿的水汽分布以及更强的冷暖空气交汇,有利于产生对流性降水。两个区域均受到多个中尺度云团的共同影响,朝阳地区初期降水由中γ尺度辐合线触发,后期台风在北上过程中与高空槽后部的干冷空气相互作用,形成的暖锋云系以及冷锋云系导致朝阳地区出现持续性强降水;加强的涡旋后部干空气侵入到暖湿水汽输送带中,配合岫岩县山区地面辐合线稳定不动,不断有积云触发并且直接影响岫岩县,导致岫岩县产生极端对流性暴雨。