scholarly journals Trends of Hydroclimatic Intensity in Colombia

Climate ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 120
Author(s):  
Oscar Mesa ◽  
Viviana Urrea ◽  
Andrés Ochoa

Prediction of precipitation changes caused by global climate change is a practical and scientific problem of high complexity. To advance, we look at the record of all available rain gauges in Colombia and at the CHIRPS database to estimate trends in essential variables describing precipitation, including HY-INT, an index of the hydrologic cycle’s intensity. Most of the gauges and cells do not show significant trends. Moreover, the signs of the statistically significant trends are opposite between the two datasets. Satisfactory explanation for the discrepancy remains open. Among the CHIRPS database’s statistically significant trends, the western regions (Pacific and Andes) tend to a more intense hydrologic cycle, increasing both intensity and mean dry spell length, whereas for the northern and eastern regions (Caribbean, Orinoco, and Amazon), the tendencies are opposite. This dipole in trends suggests different mechanisms: ENSO affects western Colombia more directly, whereas rainfall in the eastern regions depends more on the Atlantic Ocean, Caribbean Sea, and Amazon basin dynamics. Nevertheless, there is countrywide accord among gauges and cells with significant increasing trends for annual precipitation. Overall, these observations constitute essential evidence of the need for developing a more satisfactory theory of climate change effects on tropical precipitation.


Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1819
Author(s):  
Eleni S. Bekri ◽  
Polychronis Economou ◽  
Panayotis C. Yannopoulos ◽  
Alexander C. Demetracopoulos

Freshwater resources are limited and seasonally and spatially unevenly distributed. Thus, in water resources management plans, storage reservoirs play a vital role in safeguarding drinking, irrigation, hydropower and livestock water supply. In the last decades, the dams’ negative effects, such as fragmentation of water flow and sediment transport, are considered in decision-making, for achieving an optimal balance between human needs and healthy riverine and coastal ecosystems. Currently, operation of existing reservoirs is challenged by increasing water demand, climate change effects and active storage reduction due to sediment deposition, jeopardizing their supply capacity. This paper proposes a methodological framework to reassess supply capacity and management resilience for an existing reservoir under these challenges. Future projections are derived by plausible climate scenarios and global climate models and by stochastic simulation of historic data. An alternative basic reservoir management scenario with a very low exceedance probability is derived. Excess water volumes are investigated under a probabilistic prism for enabling multiple-purpose water demands. Finally, this method is showcased to the Ladhon Reservoir (Greece). The probable total benefit from water allocated to the various water uses is estimated to assist decision makers in examining the tradeoffs between the probable additional benefit and risk of exceedance.



2017 ◽  
Author(s):  
Pei Hou ◽  
Shiliang Wu ◽  
Jessica L. McCarty

Abstract. Wet deposition driven by precipitation is an important sink for atmospheric aerosols and soluble gases. We investigate the sensitivity of atmospheric aerosol lifetimes to precipitation intensity and frequency in the context of global climate change. Our study, based on the GEOS-Chem model simulation, shows that the removal efficiency and hence the atmospheric lifetime of aerosols have significantly higher sensitivities to precipitation frequencies than to precipitation intensities, indicating that the same amount of precipitation may lead to different removal efficiencies of atmospheric aerosols. Combining the long-term trends of precipitation patterns for various regions with the sensitivities of atmospheric aerosols lifetimes to various precipitation characteristics allows us to examine the potential impacts of precipitation changes on atmospheric aerosols. Analyses based on an observational dataset show that precipitation frequency in some regions have decreased in the past 14 years, which might increase the atmospheric aerosol lifetimes in those regions. Similar analyses based on multiple reanalysis meteorological datasets indicate that the precipitation changes over the past 30 years can lead to perturbations in the atmospheric aerosol lifetimes by 10 % or higher at the regional scale.



2020 ◽  
Vol 375 (1794) ◽  
pp. 20190128 ◽  
Author(s):  
C. Soto-Navarro ◽  
C. Ravilious ◽  
A. Arnell ◽  
X. de Lamo ◽  
M. Harfoot ◽  
...  

Integrated high-resolution maps of carbon stocks and biodiversity that identify areas of potential co-benefits for climate change mitigation and biodiversity conservation can help facilitate the implementation of global climate and biodiversity commitments at local levels. However, the multi-dimensional nature of biodiversity presents a major challenge for understanding, mapping and communicating where and how biodiversity benefits coincide with climate benefits. A new integrated approach to biodiversity is therefore needed. Here, we (a) present a new high-resolution map of global above- and below-ground carbon stored in biomass and soil, (b) quantify biodiversity values using two complementary indices (BIp and BIr) representing proactive and reactive approaches to conservation, and (c) examine patterns of carbon–biodiversity overlap by identifying 'hotspots' (20% highest values for both aspects). Our indices integrate local diversity and ecosystem intactness, as well as regional ecosystem intactness across the broader area supporting a similar natural assemblage of species to the location of interest. The western Amazon Basin, Central Africa and Southeast Asia capture the last strongholds of highest local biodiversity and ecosystem intactness worldwide, while the last refuges for unique biological communities whose habitats have been greatly reduced are mostly found in the tropical Andes and central Sundaland. There is 38 and 5% overlap in carbon and biodiversity hotspots, for proactive and reactive conservation, respectively. Alarmingly, only around 12 and 21% of these proactive and reactive hotspot areas, respectively, are formally protected. This highlights that a coupled approach is urgently needed to help achieve both climate and biodiversity global targets. This would involve (1) restoring and conserving unprotected, degraded ecosystems, particularly in the Neotropics and Indomalaya, and (2) retaining the remaining strongholds of intactness. This article is part of the theme issue ‘Climate change and ecosystems: threats, opportunities and solutions’.



2019 ◽  
Vol 232 ◽  
pp. 751-758 ◽  
Author(s):  
Marcos L.S. Oliveira ◽  
Carolina Dario ◽  
Bernardo F. Tutikian ◽  
Hinoel Z. Ehrenbring ◽  
Caliane C.O. Almeida ◽  
...  


2016 ◽  
Author(s):  
Jane E. Smyth ◽  
Rick D. Russotto ◽  
Trude Storelvmo

Abstract. The fundamental role of the hydrological cycle in the global climate system motivates thorough evaluation of its responses to climate change and mitigation. The Geoengineering Model Intercomparison Project (GeoMIP) is a global collaboration that aims to assess the climate impacts of solar geoengineering, a proposal to counteract global warming with a reduction of incoming solar radiation. We assess the mechanisms underlying the rainfall response to a simplified simulation of solar dimming in the suite of GeoMIP models and identify robust features. While solar geoengineering restores preindustrial temperatures, the global hydrology is altered. Tropical precipitation changes dominate the response across the model suite. The models indicate a range of possibilities for the hydrological response, and in most cases, both thermodynamic and non-thermodynamic mechanisms drive precipitation minus evaporation changes in the geoengineered simulations relative to the preindustrial. Shifts of the Hadley circulation cells cause greater rainfall anomalies than local changes in relative humidity or the Clausius-Clapeyron scaling of precipitation minus evaporation. The variations among models in the movement of the intertropical convergence zone highlights the need for cautious consideration and continued study before any implementation of solar geoengineering.



2016 ◽  
Vol 61 (5) ◽  
pp. 1891-1899 ◽  
Author(s):  
Franziska Julie Werner ◽  
Angelika Graiff ◽  
Birte Matthiessen


Significance COP22 has been dubbed "the COP of action, adaptation and Africa". It is a key opportunity to build confidence in the system of global cooperation adopted at the Paris Climate Conference. The Paris meeting ushered in a new framework for cooperation on climate change based on voluntary emissions reductions targets that will be jointly reviewed every five years. Negotiators gathering in Marrakech for COP22 face the task of making the Paris Agreement work -- and delivering results on a sufficiently large scale. Impacts Cooperation under the Paris framework will help reduce climate change effects, though overshooting of the 2 degree target is inevitable. The Paris deal's reliance on peer pressure and self-policing will risk national-level backsliding during the implementation process. Actions taken in the next ten years will determine the impact of climate change on global growth prospects for the whole of this century.



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