Distribution of Articles published per year
(2015 - 2018)
(2015 - 2018)
Total number of journals
Article 0 Reads 0 Citations Influence of longer dry seasons in the Southern Amazon on patterns of water vapor transport over northern South America ... Published: 02 June 2018
Climate Dynamics, doi: 10.1007/s00382-018-4285-1
Several studies have identified a recent lengthening of the dry season over the southern Amazon during the last three decades. Some explanations to this lengthening suggest the influence of changes in the regional circulation over the Atlantic and Pacific oceans, whereas others point to the influence of vegetation changes over the Amazon rainforest. This study aims to understand the implications of more frequent long dry seasons in this forest on atmospheric moisture transport toward northern South America and the Caribbean region. Using a semi-Langrangian model for water vapor tracking, results indicate that longer dry seasons in the southern Amazon relate to reductions of water vapor content over the southern and eastern Amazon basin, due to significant reductions of evaporation and recycled precipitation rates in these regions, especially during the transition from dry to wet conditions in the southern Amazon. On the other hand, longer dry seasons also relate to enhanced atmospheric moisture content over the Caribbean and northern South America regions, mainly due to increased contributions of water vapor from oceanic regions and the increase of surface moisture convergence over the equatorial region. This highlights the importance of understanding the relative role of regional circulation and local surface conditions on modulating water vapor transport toward continental regions.
Article 0 Reads 1 Citation Reducing social vulnerability to environmental change: building trust through social collaboration on environmental moni... Published: 01 January 2016
Weather, Climate, and Society, doi: 10.1175/wcas-d-15-0049.1
One of the most socially-relevant challenges for managing the effects of global environmental change in modern societies is associated with the need to develop risk management strategies for both natural and social catastrophic events. Such need comes from the combined effects of enhanced probability of occurrence of natural and socio-natural hazards and increased vulnerability, particularly in the most disfavored societies and communities within them. Most cases of enhanced vulnerability occur in, but are not limited to, developing countries, where the combination of social inequity, inappropriate use of natural resources, population displacement, and institutional mistrust, among other factors, make risk management particularly challenging. This paper presents a vulnerability-centered risk management framework based on social cohesion and integration principles that combined with scientific, technical, and popular knowledge, lead to the development of social networks of risk reduction. This framework is intended as a strategy to strengthen Early Warning Systems (EWS), where the human-related factor is among their most challenging components. Using water-related hazards as a case study, this paper describes the experience of the conformation of a social network for environmental monitoring using this model example on vulnerability reduction in the rural areas of the central Andes in Colombia. This experience allowed the effective conformation of a social network for environmental monitoring in 80 municipalities of Colombia, where communities developed a sense of ownership with the instrumentation and the network, strengthening links with local authorities and contributing to more efficient EWS. This work constitutes a novel experience about vulnerability reduction in Colombia.
Article 2 Reads 10 Citations A correlated shortening of the North and South American monsoon seasons in the past few decades Published: 25 February 2015
Climate Dynamics, doi: 10.1007/s00382-015-2533-1
Our observational analysis shows that the wet seasons of the American monsoon systems have shortened since 1978 due to correlated earlier retreats of the North American monsoon (NAM) and late onsets of the southern Amazon wet season, an important part of the South American monsoon (SAM). These changes are related to the combination of the global sea surface temperature (SST) warming mode, the El Niño-Southern Oscillation (ENSO), the Atlantic Multidecadal Oscillation (AMO), the westward shift of the North Atlantic subtropical high (NASH), and the enhancement of Pacific South American and Pacific North American wave train patterns, which induces variations of the regional circulation at interannual and decadal scales. The joint contributions from these forcing factors are associated with a stronger and more equatorward regional Hadley cell, which enhances convergence towards the equator, strengthening and possibly delaying the retreat of the tropical part of the NAM. This in turn accelerates the demise of the northern NAM and delays the reversal of the cross-equatorial flow over South America, reducing moisture transport to the SAM and delaying its onset. In addition, the thermodynamic response to warming appears to cause local drier land conditions over both regions, reinforcing the observed changes in these monsoons. Although previous studies have identified the isolated influence of the regional Hadley cell, ENSO, AMO, global SST warming, and NASH on the NAM, the correlated changes between NAM and SAM through variations of the cross-equatorial flow had not been established before.
Article 1 Read 9 Citations Moisture sources to the 2010–2012 anomalous wet season in northern South America Published: 10 February 2015
Climate Dynamics, doi: 10.1007/s00382-015-2511-7
During 2010–2012, northern South America experienced one of the strongest wet seasons during the recent decades, with socio-economic implications of wide proportions. This period was characterized by two stronger-than-average La Niña events, one occurred in 2010–2011 and another less intense event in 2011–2012. This study focused on identifying the main moisture sources, besides the eastern Pacific, for the anomalous wet season occurred in this region during 2010–2012, and their association with the La Niña events observed in the equatorial Pacific. The results discussed here suggest that the main moisture sources to this anomalous wet season were the Pacific Ocean (via the westerly flow of the Choco jet) and the Caribbean Sea (via the weakening of the Caribbean low-level jet and the development of southward anomalies toward northern South America). Such changes appear to be associated not only to El Niño-Southern Oscillation (ENSO)-driven sea surface temperature anomalies in the eastern Pacific, Caribbean Sea, and north Atlantic, but also to ENSO-independent variability in the Atlantic Ocean. The latter is related to an enhanced Atlantic Meridional Mode.