scholarly journals Climate Variability and Change in Central America: What Does It Mean for Water Managers?

2021 ◽  
Vol 2 ◽  
Author(s):  
Hugo G. Hidalgo

Central America is a unique climate region in the world, due to its location and shape, as well as the many large and local scale climate processes that influence its variability and change at a large range of spatial and time scales. Observed temperature trends have been increasing significantly and they are expected to increase even more in the future, potentially increasing aridity. Managers should make an informed decision on whether a sophisticated modeling approach is best for your region, or simpler approaches are available for determining shorter term planning. Always ask and question the uncertainty of information that is presented. Use this modeling information as a dynamic and constantly changing effort, as future evolves new analysis would need to be performed as models and data become more accurate.

Author(s):  
Anjuli S. Bamzai

In the years following the Second World War, the U.S. government played a prominent role in the support of basic scientific research. The National Science Foundation (NSF) was created in 1950 with the primary mission of supporting fundamental science and engineering, excluding medical sciences. Over the years, the NSF has operated from the “bottom up,” keeping close track of research around the United States and the world while maintaining constant contact with the research community to identify ever-moving horizons of inquiry. In the 1950s the field of meteorology was something of a poor cousin to the other branches of science; forecasting was considered more of trade than a discipline founded on sound theoretical foundations. Realizing the importance of the field to both the economy and national security, the NSF leadership made a concerted effort to enhance understanding of the global atmospheric circulation. The National Center for Atmospheric Research (NCAR) was established to complement ongoing research efforts in academic institutions; it has played a pivotal role in providing observational and modeling tools to the emerging cadre of researchers in the disciplines of meteorology and atmospheric sciences. As understanding of the predictability of the coupled atmosphere-ocean system grew, the field of climate science emerged as a natural outgrowth of meteorology, oceanography, and atmospheric sciences. The NSF played a leading role in the implementation of major international programs such as the International Geophysical Year (IGY), the Global Weather Experiment, the World Ocean Circulation Experiment (WOCE) and Tropical Ocean Global Atmosphere (TOGA). Through these programs, understanding of the coupled climate system comprising atmosphere, ocean, land, ice-sheet, and sea ice greatly improved. Consistent with its mission, the NSF supported projects that advanced fundamental knowledge of forcing and feedbacks in the coupled atmosphere-ocean-land system. Research projects have included theoretical, observational, and modeling studies of the following: the general circulation of the stratosphere and troposphere; the processes that govern climate; the causes of climate variability and change; methods of predicting climate variations; climate predictability; development and testing of parameterization of physical processes; numerical methods for use in large-scale climate models; the assembly and analysis of instrumental and/or modeled climate data; data assimilation studies; and the development and use of climate models to diagnose and simulate climate variability and change. Climate scientists work together on an array of topics spanning time scales from the seasonal to the centennial. The NSF also supports research on the natural evolution of the earth’s climate on geological time scales with the goal of providing a baseline for present variability and future trends. The development of paleoclimate data sets has resulted in longer term data for evaluation of model simulations, analogous to the evaluation using instrumental observations. This has enabled scientists to create transformative syntheses of paleoclimate data and modeling outcomes in order to understand the response of the longer-term and higher magnitude variability of the climate system that is observed in the geological records. The NSF will continue to address emerging issues in climate and earth-system science through balanced investments in transformative ideas, enabling infrastructure and major facilities to be developed.


2014 ◽  
Vol 27 (5) ◽  
pp. 2125-2142 ◽  
Author(s):  
John T. Abatzoglou ◽  
David E. Rupp ◽  
Philip W. Mote

Abstract Observed changes in climate of the U.S. Pacific Northwest since the early twentieth century were examined using four different datasets. Annual mean temperature increased by approximately 0.6°–0.8°C from 1901 to 2012, with corroborating indicators including a lengthened freeze-free season, increased temperature of the coldest night of the year, and increased growing-season potential evapotranspiration. Seasonal temperature trends over shorter time scales (<50 yr) were variable. Despite increased warming rates in most seasons over the last half century, nonsignificant cooling was observed during spring from 1980 to 2012. Observations show a long-term increase in spring precipitation; however, decreased summer and autumn precipitation and increased potential evapotranspiration have resulted in larger climatic water deficits over the past four decades. A bootstrapped multiple linear regression model was used to better resolve the temporal heterogeneity of seasonal temperature and precipitation trends and to apportion trends to internal climate variability, solar variability, volcanic aerosols, and anthropogenic forcing. The El Niño–Southern Oscillation and the Pacific–North American pattern were the primary modulators of seasonal temperature trends on multidecadal time scales: solar and volcanic forcing were nonsignificant predictors and contributed weakly to observed trends. Anthropogenic forcing was a significant predictor of, and the leading contributor to, long-term warming; natural factors alone fail to explain the observed warming. Conversely, poor model skill for seasonal precipitation suggests that other factors need to be considered to understand the sources of seasonal precipitation trends.


2014 ◽  
Vol 27 (10) ◽  
pp. 3492-3504 ◽  
Author(s):  
Jiaxin Feng ◽  
Zhaohua Wu ◽  
Guosheng Liu

Abstract The process of obtaining key information on climate variability and change from large climate datasets often involves large computational costs and removal of noise from the data. In this study, the authors accelerate the computation of a newly developed, multidimensional temporal–spatial analysis method, namely multidimensional ensemble empirical mode decomposition (MEEMD), for climate studies. The original MEEMD uses ensemble empirical mode decomposition (EEMD) to decompose the time series at each grid point and then pieces together the temporal–spatial evolution of climate variability and change on naturally separated time scales, which is computationally expensive. To accelerate the algorithm, the original MEEMD is modified by 1) using principal component analysis (PCA) to transform the original temporal–spatial multidimensional climate data into principal components (PCs) and corresponding empirical orthogonal functions (EOFs); 2) retaining only a small fraction of PCs and EOFs that contain spatially and temporally coherent structures; 3) decomposing PCs into oscillatory components on naturally separated time scales; and 4) obtaining the original MEEMD components on naturally separated time scales by summing the contributions of the similar time scales from different pairs of EOFs and PCs. The study analyzes extended reconstructed sea surface temperature (ERSST) to validate the accelerated (fast) MEEMD. It is demonstrated that, for ERSST climate data, the fast MEEMD can 1) compress data with a compression rate of one to two orders and 2) increase the speed of the original MEEMD algorithm by one to two orders.


JOKULL ◽  
2021 ◽  
Vol 70 ◽  
pp. 139-144
Author(s):  
Anna Líndal ◽  
Bjarki Bragason

In this article artists Anna Líndal and Bjarki Bragason discuss their work Two thousand nineteen hundred and Nineteen. The work was presented during the Iceland Glaciological Society’s (IGS) work trip to the Grímsvötn caldera in Vatnajökull glacier on 31. August 2019 in commemoration of the 100th anniversary of Hakon Wadell’s and Erik Ygberg’s 1919 expedition to the area and its subsequent mapping. Anna Líndal’s photographic work, Untouched expanse in the opening of the article addresses the importance of observing and recognizing the significance of minor events within the larger context of the environment. The Grímsvötn caldera is in the work observed as a self contained system which, although remote and harsh to its visitors, the artist proposes that it mirrors changes in the world at large. Even though footsteps trodden in the area vanish and blend into the environment, the bodily pressure of one person’s foot creates an imprint which acts as a reflector for sunbeams as ash is moved from the surface of the ice, making it more susceptible to exposure and melting. In this way the environment is continuously altered by human activity despite its constant appearance as untouched wilderness. Their two-part work presented and donated to the IGS cabin at Grímsfjall, Líndal and Bragason aimed to underscore the collision of human and geological time scales which may be discerned through the recognition of the anniversary of human eyes first laying sight on the caldera and its emergence from being an idea in the world (for example in Peter Raben’s 1720 map of Iceland) to becoming a mapped site. One component of the work is a set of cake plates which display two maps of Vatnajökull glacier, on the top side Wadell and Ygberg’s 1919 expedition path is dotted (the first recorded West-East crossing of the glacier). The underside of the plate reveals a recent map of Vatnajökull and the many, though not finite, survey lines established there in recent years and decades. Before the 22 participants in the trip to Grímsvötn drove together from the IGS cabin to the edge of the caldera, to stand in what is believed to be the spot where Wadell and Ygberg put down their tent a century ago, cake with a sugar printed map of the 1919 journey was served on the plates. The second component of the artistic gesture made during the 2019 trip was a wish from the artists to the participants in the trip to walk in silence from where the cars were parked towards the edge of the caldera. Silence in this context served as a means for individual critical and poetic reflection, offering participants for a short moment the opportunity to experience on their own terms the significance of seeing the caldera unfold in front of them at this momentous point in the site’s history.


2018 ◽  
Vol 31 (11) ◽  
pp. 4241-4263 ◽  
Author(s):  
Jean-Luc Martel ◽  
Alain Mailhot ◽  
François Brissette ◽  
Daniel Caya

Abstract Climate change will impact both mean and extreme precipitation, having potentially significant consequences on water resources. The implementation of efficient adaptation measures must rely on the development of reliable projections of future precipitation and on the assessment of their related uncertainty. Natural climate variability is a key uncertainty component, which can result in apparent decadal trends that may be greater or lower than the long-term underlying anthropogenic climate change trend. The goal of the present study is to assess how natural climate variability affects the ability to detect the climate change signal for mean and extreme precipitation. Annual and seasonal total precipitation are used as indicators of the mean, whereas annual and seasonal maximum daily precipitation are used as indicators of extremes. This is done using the CanESM2 50-member and CESM1 40-member large ensembles of simulations over the 1950–2100 period. At the local scale, results indicate that natural climate variability will dominate the uncertainty for annual and seasonal extreme precipitation going up to the end of the century in many parts of the world. The climate change signal can, however, be reliably detected much earlier at the regional scale for extreme precipitation. In the case of annual and seasonal total precipitation, the climate change signal can be reliably detected at the local scale without resorting to a regional analysis. Nonetheless, natural climate variability can impede the detection of the anthropogenic climate change signal until the middle to late century in many parts of the world for mean and extreme precipitation.


2019 ◽  
Vol 26 (2) ◽  
pp. 227-252
Author(s):  
Deborah Solomon

This essay draws attention to the surprising lack of scholarship on the staging of garden scenes in Shakespeare's oeuvre. In particular, it explores how garden scenes promote collaborative acts of audience agency and present new renditions of the familiar early modern contrast between the public and the private. Too often the mention of Shakespeare's gardens calls to mind literal rather than literary interpretations: the work of garden enthusiasts like Henry Ellacombe, Eleanour Sinclair Rohde, and Caroline Spurgeon, who present their copious gatherings of plant and flower references as proof that Shakespeare was a garden lover, or the many “Shakespeare Gardens” around the world, bringing to life such lists of plant references. This essay instead seeks to locate Shakespeare's garden imagery within a literary tradition more complex than these literalizations of Shakespeare's “flowers” would suggest. To stage a garden during the sixteenth and seventeenth centuries signified much more than a personal affinity for the green world; it served as a way of engaging time-honored literary comparisons between poetic forms, methods of audience interaction, and types of media. Through its metaphoric evocation of the commonplace tradition, in which flowers double as textual cuttings to be picked, revised, judged, and displayed, the staged garden offered a way to dramatize the tensions produced by creative practices involving collaborative composition and audience agency.


2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Alwi Musa Muzaiyin

Trade is a form of business that is run by many people around the world, ranging from trading various kinds of daily necessities or primary needs, to selling the need for luxury goods for human satisfaction. For that, to overcome the many needs of life, they try to outsmart them buy products that are useful, economical and efficient. One of the markets they aim at is the second-hand market or the so-called trashy market. As for a trader at a trashy market, they aim to sell in the used goods market with a variety of reasons. These reasons include; first, because it is indeed to fulfill their needs. Second, the capital needed to trade at trashy markets is much smaller than opening a business where the products come from new goods. Third, used goods are easily available and easily sold to buyer. Here the researcher will discuss the behavior of Muslim traders in a review of Islamic business ethics (the case in the Jagalan Kediri Trashy Market). Kediri Jagalan Trashy Market is central to the sale of used goods in the city of Kediri. Where every day there are more than 300 used merchants who trade in the market. The focus of this research is how the behavior of Muslim traders in the Jagalan Kediri Trashy Market in general. Then, from the large number of traders, of course not all traders have behavior in accordance with Islamic business ethics, as well as traders who are in accordance with the rules of Islamic business ethics. This study aims to determine how the behavior of Muslim traders in the Jagalan Kediri Trashy Market in buying and selling transactions and to find out how the behavior of Muslim traders in the Jagalan Kediri Trashy Market in reviewing Islamic business ethics. Key Words: Trade, loak market, Islamic business


2002 ◽  
Vol 33 (5) ◽  
pp. 415-424 ◽  
Author(s):  
Cintia B. Uvo ◽  
Ronny Berndtsson

Climate variability and climate change are of great concern to economists and energy producers as well as environmentalists as both affect the precipitation and temperature in many regions of the world. Among those affected by climate variability is the Scandinavian Peninsula. Particularly, its winter precipitation and temperature are affected by the variations of the so-called North Atlantic Oscillation (NAO). The objective of this paper is to analyze the spatial distribution of the influence of NAO over Scandinavia. This analysis is a first step to establishing a predictive model, driven by a climatic indicator such as NAO, for the available water resources of different regions in Scandinavia. Such a tool would be valuable for predicting potential of hydropower production one or more seasons in advance.


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