scholarly journals An uncertainty-focused database approach to extract spatiotemporal trends from qualitative and discontinuous lake-status histories

2021 ◽  
Author(s):  
Gijs De Cort ◽  
Manuel Chevalier ◽  
Sallie Burrough ◽  
Christine Chen ◽  
Sandy Harrison
Keyword(s):  
Spatiotemporal Trends ◽  
Lake Status

scholarly journals An uncertainty-focused database approach to extract spatiotemporal trends from qualitative and discontinuous lake-status histories

2021 ◽  
Vol 258 ◽  
pp. 106870
Author(s):  
Gijs De Cort ◽  
Manuel Chevalier ◽  
Sallie L. Burrough ◽  
Christine Y. Chen ◽  
Sandy P. Harrison
Keyword(s):  
Spatiotemporal Trends ◽  
Lake Status

scholarly journals Quantifying the Responses of Evapotranspiration and Its Components to Vegetation Restoration and Climate Change on the Loess Plateau of China

2021 ◽  
Vol 13 (12) ◽  
pp. 2358
Author(s):  
Linjing Qiu ◽  
Yiping Wu ◽  
Zhaoyang Shi ◽  
Yuting Chen ◽  
Fubo Zhao
Keyword(s):  
Climate Change ◽  
Loess Plateau ◽  
Dominant Role ◽  
Vegetation Restoration ◽  
Vegetation Coverage ◽  
Ecological Planning ◽  
The Loess Plateau ◽  
Canopy Interception ◽  
Community Land Model ◽  
Spatiotemporal Trends

Quantitatively identifying the influences of vegetation restoration (VR) on water resources is crucial to ecological planning. Although vegetation coverage has improved on the Loess Plateau (LP) of China since the implementation of VR policy, the way vegetation dynamics influences regional evapotranspiration (ET) remains controversial. In this study, we first investigate long-term spatiotemporal trends of total ET (TET) components, including ground evaporation (GE) and canopy ET (CET, sum of canopy interception and canopy transpiration) based on the GLEAM-ET dataset. The ET changes are attributed to VR on the LP from 2000 to 2015 and these results are quantitatively evaluated here using the Community Land Model (CLM). Finally, the relative contributions of VR and climate change to ET are identified by combining climate scenarios and VR scenarios. The results show that the positive effect of VR on CET is offset by the negative effect of VR on GE, which results in a weak variation in TET at an annual scale and an increased TET is only shown in summer. Regardless of the representative concentration pathway (RCP4.5 or RCP8.5), differences resulted from the responses of TET to different vegetation conditions ranging from −3.7 to −1.2 mm, while climate change from RCP4.5 to RCP8.5 caused an increase in TET ranging from 0.1 to 65.3 mm. These findings imply that climate change might play a dominant role in ET variability on the LP, and this work emphasizes the importance of comprehensively considering the interactions among climate factors to assess the relative contributions of VR and climate change to ET.

scholarly journals Variations in Lake Levels during the Holocene in North America: An Indicator of Changes in Atmospheric Circulation Patterns

2007 ◽  
Vol 39 (2) ◽  
pp. 141-150 ◽  
Author(s):  
S. P. Harrison ◽  
S. E. Metcalfe
Keyword(s):  
North America ◽  
General Circulation ◽  
Lake Level ◽  
Data Bank ◽  
Relative Depth ◽  
Lake Levels ◽  
Regional Patterns ◽  
Air Mass ◽  
The Holocene ◽  
Lake Status

ABSTRACT Fluctuations in the extent of closed lakes provide a detailed record of regional and continental variations in mean annual water budget. The temporal sequence of hydrological fluctuations during the Holocene in North America has been reconstructed using information from the Oxford Lake-Level Data Bank. This data base includes 67 basins from the Americas north of the equator. Maps of lake status, an index of relative depth, are presented for the period 10,000 to 0 yr BP. The early Holocene was characterised by increasingly arid conditions, which led to widespread low lake levels in the mid-latitudes by 9,000 yr BP. By 6,000 yr BP this zone of low lakes extended from 32o to 51oN. Many of the features of the present day lake-level pattern, particularly high lake levels north of 46oN and along the eastern seaboard, were established by 3.000 yr BP. Four distinctive regional patterns of lake behaviour through time are apparent. Histograms of lake status from 20,000 to 0 yr BP are presented for each of these regions. They illustrate the temporal patterns of lake-level fluctuations on a time scale of 103 — 104 yr. Changes in lake status over North America are interpreted as indicating displacements in major features of the general circulation, specifically the zonal Westerlies and the Equatorial Trough, as reflected by changes in air mass trajectories and hence the position of air mass boundaries over the continent.

scholarly journals The impact of environmental and climatic variation on the spatiotemporal trends of hospitalized pediatric diarrhea in Ho Chi Minh City, Vietnam

2015 ◽  
Vol 35 ◽  
pp. 147-154 ◽  
Author(s):  
Corinne N. Thompson ◽  
Jonathan L. Zelner ◽  
Tran Do Hoang Nhu ◽  
My VT Phan ◽  
Phuc Hoang Le ◽  
...  
Keyword(s):  
Climatic Variation ◽  
Ho Chi Minh City ◽  
Spatiotemporal Trends ◽  
The Impact

scholarly journals Evapotranspiration Intensification Over Unchanged Temperate Vegetation in the Baltic Countries Is Being Driven by Climate Shifts

2021 ◽  
Vol 4 ◽  
Author(s):  
Bruno Montibeller ◽  
Jaak Jaagus ◽  
Ülo Mander ◽  
Evelyn Uuemaa
Keyword(s):  
Land Cover ◽  
Remote Sensing Data ◽  
Kendall Test ◽  
Rate Of Change ◽  
Sen’S Slope ◽  
Baltic Countries ◽  
Spatiotemporal Trends ◽  
Trade Offs ◽  
The Baltic ◽  
Increasing Trends

Shifts in climate driven by anthropogenic land use and land cover change are expected to alter various land–atmosphere interactions. Evapotranspiration (ET) is one of these processes and plays a fundamental role in the hydrologic cycle. Using gridded reanalysis and remote sensing data, we investigated the spatiotemporal trends of precipitation, temperature, and ET for areas in the Baltic countries Lithuania, Latvia and Estonia where the land cover type had not changed from 2000 to 2018. We focused on ET but investigated the spatiotemporal trends for the three variables at monthly, seasonal, and annual time scales during this period to quantify trade-offs among months and seasons. We used the Mann-Kendall test and Sen’s slope to calculate the trends and rate of change for the three variables. Although precipitation showed fewer statistically significant increasing and decreasing trends due to its high variability, temperature showed only increasing trends. The trends were concentrated in late spring (May, +0.14°C annually), summer (June and August, +0.10°C), and early autumn (September, +0.13°C). For unchanged forest and cropland areas, we found no statistically significant ET trends. However, Sen’s slope indicated increasing ET in April, May, June, and September for forest areas and in May and June for cropland. Our results indicate that during the study period, the temperature changes may have lengthened the growing season, which affected the ET patterns of forest and cropland areas. The results also provide important insights into the regional water balance and complement the findings of other studies.

scholarly journals Spatiotemporal variations in exposure: Chagas disease in Colombia as a case study

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Julia Ledien ◽  
Zulma M. Cucunubá ◽  
Gabriel Parra-Henao ◽  
Eliana Rodríguez-Monguí ◽  
Andrew P. Dobson ◽  
...  
Keyword(s):  
Chagas Disease ◽  
Performance Indicator ◽  
Disease Incidence ◽  
Bootstrap Method ◽  
Model Averaging ◽  
Predictive Ability ◽  
Force Of Infection ◽  
Spatiotemporal Trends ◽  
Urban Rural ◽  
Best Fit

AbstractAge-stratified serosurvey data are often used to understand spatiotemporal trends in disease incidence and exposure through estimating the Force-of-Infection (FoI). Typically, median or mean FoI estimates are used as the response variable in predictive models, often overlooking the uncertainty in estimated FoI values when fitting models and evaluating their predictive ability. To assess how this uncertainty impact predictions, we compared three approaches with three levels of uncertainty integration. We propose a performance indicator to assess how predictions reflect initial uncertainty.In Colombia, 76 serosurveys (1980–2014) conducted at municipality level provided age-stratified Chagas disease prevalence data. The yearly FoI was estimated at the serosurvey level using a time-varying catalytic model. Environmental, demographic and entomological predictors were used to fit and predict the FoI at municipality level from 1980 to 2010 across Colombia.A stratified bootstrap method was used to fit the models without temporal autocorrelation at the serosurvey level. The predictive ability of each model was evaluated to select the best-fit models within urban, rural and (Amerindian) indigenous settings. Model averaging, with the 10 best-fit models identified, was used to generate predictions.Our analysis shows a risk of overconfidence in model predictions when median estimates of FoI alone are used to fit and evaluate models, failing to account for uncertainty in FoI estimates. Our proposed methodology fully propagates uncertainty in the estimated FoI onto the generated predictions, providing realistic assessments of both central tendency and current uncertainty surrounding exposure to Chagas disease.

scholarly journals Early-warning health and process indicators for sentinel surveillance in Madagascar 2007-2011

2014 ◽  
Vol 6 (3) ◽  
Author(s):  
Soatiana Rajatonirina ◽  
Fanjasoa Rakatomanana ◽  
Laurence Randrianasolo ◽  
Norosoa Harline Razanajatovo ◽  
Soa Fy Andriamandimby ◽  
...  
Keyword(s):  
Early Warning ◽  
Sentinel Surveillance ◽  
Warning Sign ◽  
Surveillance Network ◽  
Poor Countries ◽  
Process Indicators ◽  
Spatiotemporal Trends ◽  
Mobile Telephones ◽  
Early Warning Sign ◽  
Primary Health Centres

Background: Epidemics pose major threats in resource-poor countries, and surveillance tools for their early detection and response are often inadequate. In 2007, a sentinel surveillance system was established in Madagascar, with the aim of rapidly identifying potential epidemics of febrile or diarrhoeal syndromes and issuing alerts. We present the health and process indicators for the five years during which this system was constructed, showing the spatiotemporal trends, early-warning sign detection capability and process evaluation through timely analyses of high-quality data.Methods: The Malagasy sentinel surveillance network is currently based on data for fever and diarrhoeal syndromes collected from 34 primary health centres and reported daily via the transmission of short messages from mobile telephones. Data are analysed daily at the Institut Pasteur de Madagascar to make it possible to issue alerts more rapidly, and integrated process indicators (timeliness, data quality) are used to monitor the system.Results: From 2007 to 2011, 917,798 visits were reported. Febrile syndromes accounted for about 11% of visits annually, but the trends observed differed between years and sentinel sites. From 2007 to 2011, 21 epidemic alerts were confirmed. However, delays in data transmission were observed (88% transmitted within 24 hours in 2008; 67% in 2011) and the percentage of forms transmitted each week for validity control decreased from 99.9% in 2007 to 63.5% in 2011.Conclusion: A sentinel surveillance scheme should take into account both epidemiological and process indicators. It must also be governed by the main purpose of the surveillance and by local factors, such as the motivation of healthcare workers and telecommunication infrastructure. Permanent evaluation indicators are required for regular improvement of the system. 

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