Exploring possible connections between hydrological extreme events and climate change in central south Chile

Abstract

Motivated by recent extreme flow events in the Mataquito River located in the Mediterranean region of Chile, we performed a detailed trend analysis of critical hydroclimatic variables based on observed daily flow, precipitation and temperature within the basin. For the period 1976–2008, positive trends in temperature were observed, especially during spring and summer months. At the same time, we found negative trends in the frequency and intensity of precipitation, especially during spring months. We observed an increasing difference between average streamflow in the rainy season as compared to the snowmelt season. Part of this trend is caused by larger flows during autumn months, although no positive precipitation trends are observed for these months. Finally, significant reductions in minimum flow during spring/summer and a disproportionate concentration of high-flow events occurring in the last 10 years were also identified. These high-flow events tend to happen during autumn months, and are associated with high precipitation and high minimum temperatures. Based on a simple assessment of changes in irrigated agriculture and land use, we concluded that other non-climatic factors seem not to be as relevant to the detected flow trends. All these results are in accord with future climate change scenarios that show an increase in temperature, a reduction in average precipitation and a reduction in snow accumulation. Such future scenarios could seriously hamper the development of economic activities in this basin, exemplifying also a fate that may be shared by other similar basins in Chile and in other regions of the world.

Editor Z.W. Kundzewicz

Citation Vicuña, S., Gironás, J., Meza, F.J., Cruzat, M.L., Jelinek, M., Bustos, E., Poblete, D., and Bambach, N., 2013. Exploring possible connections between hydrological extreme events and climate change in central south Chile. Hydrological Sciences Journal, 58 (8), 1598–1619.     

Ocean and atmosphere changes in the Caribbean Sea during the twenty-first century using CMIP5 models

Ocean Dynamics - Coastal communities around the Caribbean Sea are vulnerable to global warming impacts, partly because of constraints on their adaptive capacity. We use three climate models...     

Erratum to: New paleomagnetic results from Upper Cretaceous arc-type rocks from the northern and southern branches of the Neotethys ocean in Anatolia

International Journal of Earth Sciences -     

Projections of temperature changes over South America during the twenty-first century using CMIP6 models

A 22-member ensemble from CMIP6 is used to analyze the projected changes and seasonal behavior in surface air temperature over South America during the twenty-first century. In the future projections, CMIP6 models shown a high dependency to the socioeconomic pathway over each country of South America. The multimodel ensemble projects a continuous increase in the annual mean temperature over South America during the twenty-first century under the three future scenarios (SSP1-2.6, SSP2-4.5 and SSP5-8.5). Besides, it was possible to identify consistent positive trends across all the models, with values between 0.45 ± 0.05 and 2.05 ± 0.31 °C cy⁻¹ under the historical experiment, however largest trends occurs for the projection periods (near, mid and far future), with values between − 0.87 ± 0.84 to 2.88 ± 0.60 °C cy⁻¹ (SSP1-2.6), 1.41 ± 0.88 to 5.32 ± 0.81 °C cy⁻¹ (SSP2-4.5) and 4.75 ± 0.58 to 8.76 ± 0.74 °C cy⁻¹ (SSP5-8.5) with maximum values at Bolivia, Brasil, Paraguay and Venezuela whilst minimum values for Argentina and Uruguay, regardless of the SSP scenario used. From the seasonal behavior analysis was possible to identify maximum values between January and March whilst minimum between June and July, except in Brasil, Venezuela and Guyana–Surinam–French Guayana, with annual range decreasing as the latidude decreases. By the end of the twenty-first century the annual mean temperature over South america is projected to increase between 0.92–2.11 °C, 0.97–3.37 °C and 1.27–6.14 °C under SSP1-2.6, SSP2-4.5 and SSP5-8.5 projection scenarios respectively. This projected increase of temperature across the continent will produce negative repercussions in the social, economic and political spheres. The results obtained in this study provide insights about the CMIP6 performance over this region, which can be used to develop adaptation strategies and might be useful for the adaptation to the climate change.

     

Knowledge gaps and climate adaptation policy: a comparative analysis of six Latin American countries

ABSTRACT

This article identifies and analyzes some of the main knowledge gaps that affect the development of climate adaptation policies in the Latin American context. It is based on a comparative analysis of online survey results conducted among government officials working on climate adaptation in six countries of the region: Argentina, Brazil, Chile, Costa Rica, Paraguay and Uruguay. The article addresses four key issues. First, it identifies some of the critical knowledge deficits (missing or incomplete information) that affect climate adaptation policy making and implementation. Second, it addresses the obstacles and difficulties facing collaborative processes of knowledge production (co-production) between scientists and public policy actors. Third, it analyzes factors affecting knowledge uptake and use by policymakers. Finally, it identifies some of the main knowledge deficits specifically affecting the monitoring and assessment of climate adaptation policies and measures. Overall, the article provides a diagnosis of the main knowledge gaps facing climate adaptation policy in the Latin American countries studied. The results of this diagnosis can serve as input for a research and action agenda aiming to strength the interaction between science and policy on climate adaptation in Latin American countries.

Key policy insights

• The countries covered by the study suffer strong knowledge deficits related to the design, implementation and evaluation of adaptation policy.

• Collaborative modes of knowledge production in the field of climate adaptation do not tend to sustain over time. Climate change co-production processes tend to be project based, linked to specific initiatives rather than to institutionalized long-term policymaking or planning processes.

• The fragmentation and lack of integration of the knowledge available on the different aspects of climate adaptation issues deeply affect their usability in policy processes.

• Weak state capabilities to co-produce, manage and use knowledge in the policy process constitute a main barrier affecting the science-policy interface on climate adaptation issues.

     

Detrital zircon ages from a Lower Ordovician quartzite of the İstanbul exotic terrane (NW Turkey): evidence for Amazonian affinity

NW Turkey is a mosaic of several continental and oceanic units, that were amalgamated by collisional and strike–slip tectonics. One of the continental units is the İstanbul terrane, the Palaeozoic strata of which comprise an Early Ordovician to Early Carboniferous transgressive sedimentary sequence. The basement to the Palaeozoic succession is exposed in the Bolu Massif and is represented by a thick meta-volcanic unit intruded by Late Neoproterozoic (ca. 575 Ma) felsic magma. This meta-igneous basement is considered to be a sliver of the Cadomian magmatic arc. Unconformably overlying Early Ordovician strata start with red fluvial clastics (ca. 3,000 m), overlain by shallow marine quartzites (<250 m). Detrital zircons were separated from an Ordovician quartzite sample located 5 m above the contact with the underlying red fluvial clastics. We have dated a total of 99 zircon grains by U–Pb method using laser ablation-sector field-inductively coupled plasma mass spectrometer (LA-SF-ICP-MS). The ages (97% are >90% concordant) range from 530 to 2550 Ma. The dominance (44 grains) of Neoproterozoic zircon ages (around 540, 570, 600–640 and 700–800 Ma) rules out any link of the İstanbul terrane with Baltica. The large amount (40 grains) of Grenvillian and Meso- to Palaeo-proterozoic ages (around 1.0–1.2, 1.3–1.6, 1.7–1.8, and 1.9–2.1 Ga) in the zircon population further rules out a link to Cadomian and Minoan terranes, but is indicative for Amazonian source areas. The new age data suggest the İstanbul terrane to be a peri-Gondwanan terrane that was located at the northwestern margin of Gondwana close to Amazonia. This terrane should have travelled a large distance in the Phanerozoic times.     

The Digital Archive of the Photographic Images of the Córdoba Observatory Plates Collections

The astronomical events registered in photographic plates are unique. A remarkable interest in using old plates in many areas of the current astronomical research is widely recognized by the IAU. There are almost ten thousand plates in several collections at the Córdoba Observatory and most of them are nearly one century old. This photographic material is difficult to handle in order to get the information stored in it. The goal of this project is to make a digital archive of images of these collections. In this first survey plates are being scanned with a standard commercial transparency scanner. These low spatial resolution, low digital resolution and low signal-to-noise ratio images are intended for facilitating handling and visual inspection. However, one arc-second positions can be obtained. Photometric quality has not been yet determined. Otherwise high quality digital images can be acquired with a microdenstitometer based on a scientific grade CCD whose implementation is at its final stage. The possibility of using a better-performance scanner is being evaluated. It is planned to permit the access to low-resolution images via internet. High-resolution images of selected zones will be available upon request. At this first stage, collections totally digitized at low resolution are:Carte du Ciel and Small Magellanic Cloud Zones. Gaviola's Eta Carinae Spectra and Pulkovo Zones are still in process.     

New paleomagnetic results from Upper Cretaceous arc-type rocks from the northern and southern branches of the Neotethys ocean in Anatolia

International Journal of Earth Sciences - A paleomagnetic study of Cretaceous arc type rocks in the Central-Eastern Pontides and in the Southeastern Taurides investigates the tectonic and...