scholarly journals Palaeoclimatological perspective on river basin hydrometeorology: case of the Mekong Basin

2013 ◽  
Vol 17 (5) ◽  
pp. 2069-2081 ◽  
Author(s):  
T. A. Räsänen ◽  
C. Lehr ◽  
I. Mellin ◽  
P. J. Ward ◽  
M. Kummu

Abstract. Globally, there have been many extreme weather events in recent decades. A challenge has been to determine whether these extreme weather events have increased in number and intensity compared to the past. This challenge is made more difficult due to the lack of long-term instrumental data, particularly in terms of river discharge, in many regions including Southeast Asia. Thus our main aim in this paper is to develop a river basin scale approach for assessing interannual hydrometeorological and discharge variability on long, palaeological, time scales. For the development of the basin-wide approach, we used the Mekong River basin as a case study area, although the approach is also intended to be applicable to other basins. Firstly, we derived a basin-wide Palmer Drought Severity Index (PDSI) from the Monsoon Asia Drought Atlas (MADA). Secondly, we compared the basin-wide PDSI with measured discharge to validate our approach. Thirdly, we used basin-wide PDSI to analyse the hydrometeorology and discharge of the case study area over the study period of 1300–2005. For the discharge-MADA comparison and hydrometeorological analyses, we used methods such as linear correlations, smoothing, moving window variances, Levene type tests for variances, and wavelet analyses. We found that the developed basin-wide approach based on MADA can be used for assessing long-term average conditions and interannual variability for river basin hydrometeorology and discharge. It provides a tool for studying interannual discharge variability on a palaeological time scale, and therefore the approach contributes to a better understanding of discharge variability during the most recent decades. Our case study revealed that the Mekong has experienced exceptional levels of interannual variability during the post-1950 period, which could not be observed in any other part of the study period. The increased variability was found to be at least partly associated with increased El Niño Southern Oscillation (ENSO) activity.

2021 ◽  
Author(s):  
Ramesh Lilwah

Close to ninety percent of Guyana‟s population live along a low lying coastal plain, which is below sea level and very vulnerable to the impacts of climate change. While the national government has not yet developed a comprehensive climate policy, the potential impacts of climate change is considered in several sectoral policies, much of which emphasize mitigation, with little focus on adaptation. This research examined the current priorities for adaptation by a review of the policies within the natural resource sector to identify opportunities for adaptation, especially ecosystem based adaptation. A Diagnostic Adaptation Framework (DAF) was used to help identify approaches to address a given adaptation challenge with regards to needs, measures and options. A survey questionnaire was used to support the policy reviews and identified four key vulnerabilities: coastal floods; sea level rise; drought and extreme weather events. The application of the DAF in selecting an adaptation method suggests the need for more data on drought and extreme weather events. Coastal flooding is addressed, with recognized need for more data and public awareness for ecosystem based adaptation


2018 ◽  
Vol 2 (1) ◽  
pp. 9-24
Author(s):  
Edoardo Bertone ◽  
Oz Sahin ◽  
Russell Richards ◽  
Anne Roiko

Abstract A decision support tool was created to estimate the treatment efficiency of an Australian drinking water treatment system based on different combinations of extreme weather events and long-term changes. To deal with uncertainties, missing data, and nonlinear behaviours, a Bayesian network (BN) was coupled with a system dynamics (SD) model. The preliminary conceptual structures of these models were developed through stakeholders' consultation. The BN model could rank extreme events, and combinations of them, based on the severity of their impact on health-related water quality. The SD model, in turn, was used to run a long-term estimation of extreme events' impacts by including temporal factors such as increased water demand and customer feedback. The integration of the two models was performed through a combined Monte Carlo–fuzzy logic approach which allowed to take the BN's outputs as inputs for the SD model. The final product is a participatory, multidisciplinary decision support system allowing for robust, sustainable long-term water resources management under uncertain conditions for a specific location.


2013 ◽  
Vol 72 (1) ◽  
pp. 87-107 ◽  
Author(s):  
Evangelos Mitsakis ◽  
Iraklis Stamos ◽  
Anestis Papanikolaou ◽  
Georgia Aifadopoulou ◽  
Haris Kontoes

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 99
Author(s):  
Micah Hewer

This study devises a novel approach for defining extreme weather events and assessing their effects on human participation in recreation and tourism, based on a case study of attendance at the Toronto Zoo (Toronto, ON, Canada). Daily zoo attendance data from 1999 to 2018 was obtained and analyzed in connection with daily weather data from local weather stations for the maximum temperature, minimum temperature, total precipitation, and maximum wind speed. The “climatic distance” method, used for evaluating representative weather stations for case studies in applied climatology, was employed to rank and select surrounding weather stations that most accurately captured daily weather observations recorded at the Toronto Zoo from 1990 to 1992. Extreme weather events can be defined as lying in the outermost (most unusual) 10 percent of a place’s history. Using this definition as the foundation, a percentile approach was developed to identify and assess the effects of extreme weather events across the following thresholds: the 99th percentile, the 95th percentile, and the 90th percentile, as well as less than the 1st percentile, less than the 5th percentile, and less than the 10th percentile. Additionally, revealed, theoretical, and binary thresholds were also assessed to verify their merit and determine their effects, and were compared to the extreme weather events defined by the percentiles approach. Overall, extreme daily weather events had statistically significant negative effects on zoo attendance in Toronto, apart from a few cases, such as the positive effect of usually warm daytime temperatures in the winter and usually cool nighttime temperatures in the summer. The most influential weather event across all seasons was extremely hot temperatures, which has important implications for climate change impact assessments.


2020 ◽  
Author(s):  
Assaf Hochman ◽  
Pinhas Alpert ◽  
Hadas Saaroni ◽  
Tzvi Harpaz ◽  
Joaquim G. Pinto ◽  
...  

<p>Extreme weather events have long been considered challenging to predict. It is likely that global warming will trigger extreme weather in many regions of the globe and especially over the Mediterranean ´hot spot´. Therefore, extreme weather events have been selected as one of the grand challenges of the World Climate Research Program.</p><p>The intrinsic predictability of a weather system, or any dynamical system, depends on its persistence and its active number of degrees of freedom. Recent developments in dynamical systems theory allow to compute these metrics for atmospheric configurations (1). In most of the mid-latitudes, synoptic scale patterns exert a strong control on regional weather, thus, stimulating a broad interest, especially in weather forecasting. Recently, we have integrated the dynamical systems approach with a synoptic classification algorithm over the Eastern Mediterranean (2).  It was shown that the dynamical systems perspective provides an extremely informative tool for evaluating the predictability of synoptic patterns and especially of weather extremes.</p><p>The novel perspective, which leverages a dynamical systems approach to investigate the predictability of extreme weather events, outlines a new avenue of research that may be fruitfully applied at operational weather and climate forecasting services in the Mediterranean Region and around the globe.</p><p><strong>References</strong></p><ol><li>Faranda D, Messori G, Yiou P. 2017. Dynamical Proxies of North Atlantic Predictability and Extremes. Scientific Reports <strong>7</strong>, 412782017b. DOI: 10.1038/srep4127</li> <li>Hochman A, Alpert P, Harpaz T, Saaroni H, Messori G. 2019. A New Dynamical Systems Perspective on Atmospheric Predictability; Eastern Mediterranean Weather Regimes as a Case Study. Science Advances <strong>5</strong>. DOI: 10.1126/sciadv.aau0936</li> </ol>


Sign in / Sign up

Export Citation Format

Share Document