scholarly journals Trend Analysis of Lakes and Sinkholes in Konya Closed Basin, Turkey

2021 ◽  
Author(s):  
Vahdettin DEMIR
Keyword(s):  
Trend Analysis ◽  
Flood Control ◽  
Statistical Tests ◽  
Water Levels ◽  
Trend Test ◽  
Lake Levels ◽  
Closed Basin ◽  
Thiessen Polygons ◽  
Over Time

Abstract Determining changes in the water level of lakes is essential in terms of flood control, water resource management, economic development, water-supply planning sustainability, and the sustainability of the ecosystem. Trend analysis is one of the most commonly used tools for detecting changes in the hydrological time series such as lake levels, precipitation and temperature. Trend analyses of meteorological variables and groundwater levels (baseflow components) are crucial toward the assessment of long-term changes in lake levels. This study aims to investigate the trend of long-term change in lakes (Lake Tuz and Lake Beyşehir) and sinkholes (Timraş and Kızören) in the Konya Closed Basin in Turkey. Changes in these lakes and sinkholes were examined along with changes in precipitation and groundwater trends representing the climate in the region. With the assistance of Thiessen polygons, precipitation stations, which affect the lakes and sinkholes, were determined. Several statistical tests exist that help determine the significance of hydrological trends over time. These tests are divided into two categories: parametric and nonparametric. In this study, the non parametric Innovative Sen trend test, the Modified Mann–Kendall trend test, and the parametric Linear Trend test were used. As a result of the trend analysis, it was observed that the water levels of Kızören and Timraş sinkholes decreased over time, and the water levels of Tuz Gölü and Beyşehir lakes increased over time. These results are supported by the trends of precipitation data and groundwater level data of the stations determined by the Thiessen polygons and sub-basin boundaries.

scholarly journals Productivity of Ospreys, Pandion haliaetus, Affected by Water Levels Near Loon Lake, Saskatchewan, 1975-2002

2010 ◽  
Vol 124 (3) ◽  
pp. 219
Author(s):  
C. Stuart Houston ◽  
Frank Scott ◽  
Rob B. Tether
Keyword(s):  
Breeding Success ◽  
Water Levels ◽  
Lake Levels ◽  
The West ◽  
Canadian Data ◽  
Human Use ◽  
The Town ◽  
Western Half ◽  
Eastern Half

Between 1975 and 2002, diminished breeding success of Ospreys was associated with drought and falling lake levels in the western half of our study area near the town of Loon Lake, west-central Saskatchewan. Only 46% of nest attempts were successful in the west compared to 72% in the east, producing 0.88 young per accessible nest in the west and 1.42 in the east. Breeding success was greater in the eastern half, where water levels were stable, in spite of increased human use of the resort lakes there. Our unique long-term Canadian data base results support Ogden's 1977 prediction that Osprey productivity may decrease when water levels drop and fish populations are reduced.

Abstract P35: The Trend of Stroke Rehabilitation Utilization Between 2014- 2019 in a Community Based Study

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Daniel Uhm ◽  
Esther Olasoji ◽  
Alexis N Simpkins ◽  
Carolyn Geis ◽  
Keyword(s):  
Clinical Practice ◽  
Trend Analysis ◽  
Significant Proportion ◽  
Inpatient Rehabilitation ◽  
Outpatient Rehabilitation ◽  
Rehabilitation Services ◽  
Institutional Review ◽  
Ischemic Attack ◽  
Over Time

Introduction: Stroke is the leading cause of long-term disability in adults, resulting in significant impairments in motor, sensory, and/ or cognitive that often requires continued rehabilitation services, which vary from intensive acute inpatient rehabilitation to outpatient rehabilitation services. Efforts to reduce disability have advanced rapidly over the past several years. Our data analysis was undertaken to assess whether recent changes in clinical practice have impacted the proportion of stroke patients receiving inpatient versus outpatient rehabilitation over time between 2014-2019 at our institution, which serves a diverse mix of rural, suburban, and urban populations. Methods: Our Institutional Review Board approved retrospective stroke database, including adult patients discharged to receive rehabilitation services data from 2014-2019, was used for analysis. Cochran-Armitage trend analysis was used to assess for differences type of rehabilitation services used over time and regression analysis was used to identify clinical factors associated with discharge type over time. Results: A total of 3467 patients were included in the analysis, 50% woman, 1% Asian, 20% Black, 75% White, 4% undetermined race, 17% intracerebral hemorrhage, 65% ischemic stroke, 11% subarachnoid hemorrhage, 3% transient ischemic attack, 3% other cerebrovascular disease. In this community population, 65% were discharged to inpatient rehab. Trend analysis demonstrated a significant increase in the proportion of patients being discharged home with rehab services, p<.0001. In comparison to those discharged home, patients discharged to rehab were older (odds ratio (OR) 1.02, confidence interval (CI) 1.02-1.03), with a higher NIHSS (OR 1.16, CI 1.14-1.18), discharged in 2014 (OR 1.72, CI 1.23-2.39) or 2016 (OR 1.46, CI 1.05-2.05) versus 2019. There was no association with race, gender, or discharge in 2015, 2017, or 2018. Discussion: Our findings demonstrate the community impact of recent changes in clinical practice guidelines for stroke. The increasing trend of home discharges is encouraging, but the significant proportion of those still not discharged home suggests there is still more work to be done to reduce stroke associated disability in adults.

scholarly journals Analyzing Trends in Water Table Elevations at the Marcell Experimental Forest, Minnesota, U.S.A.

2021 ◽  
Vol 17 (4) ◽  
pp. 19-32
Author(s):  
Anna Stockstad ◽  
Ella Gray ◽  
Stephen Sebestyen ◽  
Nina Lany ◽  
Randall Kolka ◽  
...  
Keyword(s):  
Water Table ◽  
Linear Trend ◽  
Forest Products ◽  
Water Levels ◽  
Monthly Precipitation ◽  
Significant Linear Trend ◽  
Water Table Fluctuations ◽  
Water Tables ◽  
Over Time

Water table fluctuations in peatlands are closely coupled with the local climate setting and drive critical ecosystem processes such as nutrient cycling. In Minnesota, USA, peatlands cover ten percent of the surface area, approximately 2.5 million hectares, some of which are actively managed for forest products. To explore the relationship between peatland water tables and precipitation, long-term data (1961 to 2019) were used from the Marcell Experimental Forest in northern Minnesota. Starting in 1961, water table data from seven peatlands, including two types of peatlands (bogs and fens), were measured. We used the Theil-Sen estimator to test for monotonic trends in mean monthly water table elevations for individual peatlands and monthly precipitation. Water levels in bogs were both more variable and had mean water table elevations that were closer to the surface. Individual trends of water table elevations differed among peatlands. Water table elevations increased over time in three of the bogs studied and decreased over time in two of the bogs studied. Trends within fens were notably nonlinear across time. No significant linear trend was found for mean monthly precipitation between 1961 and 2019. These results highlight differences in peatlands types, local physiography, and the importance of understanding how changes in long-term dynamics coupled with changing current conditions will influence the effects of water table fluctuations on ecosystem services. The variability of water table elevations in bogs poses potential difficulties in modeling these ecosystems or creating adaptive management plans. KEYWORDS: Peatlands; Hydrology; Water tables; Bogs; Fens; Monitoring; Minnesota; Climate Change

scholarly journals Changes in precipitation rates over the last 70 years in Eastern Paraná State, Brazil

2021 ◽  
Vol 43 ◽  
pp. e15
Author(s):  
Bruno Henrique Toná Juliani ◽  
Cristhiane Michiko Passos Okawa ◽  
Miriam Rita Moro Mine
Keyword(s):  
Change Point ◽  
Abrupt Change ◽  
Historical Data ◽  
Statistical Tests ◽  
Positive Trend ◽  
Medium Term ◽  
Complete Series ◽  
Joseph Effect ◽  
Over Time

Temporal hydrometeorological series may present variations over time. The awareness of these characteristics is important to improve the monitoring of changes that these series may suffer along time. In this regard, the present paper aims to identify the existence of precipitation trends for the east portion of Paraná state, in Brazil, and also investigate the changes in the observed rates over the last 70 years. The statistical tests of Mann-Kendall and Pettitt, and also the Theil-Sen estimator, are applied for series of precipitation from 13 pluviometric stations of eastern Paraná state, Brazil, with 70 years of data records. By the results it was identified long-term linear positive trend for 11 of the precipitation series and also detected medium-term patterns in precipitation over 10 stations, characterizing the Joseph effect. These series have presented a behavior with higher rates in the most recent years in comparison from the first years of the historical data, sectioning the complete series into two shorter stationary periods, and presenting an abrupt change point.

scholarly journals Long-term trend analysis of rainfall using hybrid Discrete Wavelet Transform (DWT) based Mann-Kendall tests in central Gujarat region, India

MAUSAM ◽  
2021 ◽  
Vol 71 (2) ◽  
pp. 209-224
Author(s):  
RAJANI NIRAV V ◽  
TIWARI MUKESH K ◽  
CHINCHORKAR S S
Keyword(s):  
Time Series ◽  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Trend Analysis ◽  
Time Scales ◽  
Series Data ◽  
Trend Test ◽  
Discrete Wavelet ◽  
Rainfall Time Series

Trend analysis has become one of the most important issues in hydro-meteorological variables study due to climate change and the focus given to it in the recent past from the scientific community. In this study, long-term trends of rainfall are analyzed in eight stations located in semi-arid central Gujarat region, India by considering time series data of 116 years (1901-2016). Discrete wavelet transform (DWT) as a dyadic arrangement of continuous wavelet transformation combined with the widely applied and acknowledged Mann-Kendall (MK) trend analysis method were applied for analysis of trend and dominant periodicities in rainfall time series at monthly, annual and monsoonal time scales. Initially, rainfall time series applied in this study were decomposed using DWT to generate sub-time series at high and low frequencies, before applying the MK trend test. Further, the Sequential Mann-Kendall (SQMK) test was also applied to find out the trend changing points. The result showed that at the monthly annual and monsoon time scales, the trends in rainfall were significantly decreasing in most of the station. The 4-month and 8-month components were found as dominant at the monthly time series and the 2-year and 4-year component were found as dominant at the monsoon time series, whereas the 2-year components were observed as dominant in the annual time scale.

An example of the application of statistical techniques to predict lake level elevations

1981 ◽  
Vol 8 (2) ◽  
pp. 114-121 ◽  
Author(s):  
Sivajogi D. Koppula
Keyword(s):  
Lake Water ◽  
Stormwater Management ◽  
Flood Control ◽  
Water Levels ◽  
Control Measures ◽  
Lake Levels ◽  
Lake District ◽  
Management Objectives ◽  
Future Events ◽  
Better Than

A knowledge of future lake levels is helpful in the stormwater management of a lake district with respect to flood control measures, land use measures around the lake, etc. The planning of strategies to achieve management objectives often receives wide attention; however, little or no mention is usually made of prediction of future events, e.g., lake water levels, upon which the strategies are based. These future events are of major importance as they determine the type of objectives and hence the strategies that management will have to develop and follow in the future.In the present study, the available data on monthly lake water levels are examined utilizing two statistical methods, namely, the Box-Jenkins time series analysis and harmonic analysis. The statistical models are then used to predict future lake levels; the predictions are compared with actual observations. It has been found that the predictions made by the Box-Jenkins model are closer to the recorded observations. The results from the two independent methods are combined to yield a composite forecast, which gives results that are slightly better than those given by either of the independent methods.

scholarly journals BREAKS AND LONG TERM TRENDS OF TIDAL CHARACTERISTICS IN THE SOUTHERN GERMAN BIGHT

2012 ◽  
Vol 1 (33) ◽  
pp. 32
Author(s):  
Sabine Jenning ◽  
Hartmut Hein ◽  
Stephan Mai ◽  
Holger Schüttrumpf
Keyword(s):  
Time Series ◽  
German Bight ◽  
Tide Gauge ◽  
Zero Point ◽  
Water Levels ◽  
Long Time ◽  
Long Term Trends ◽  
Tidal Characteristics ◽  
Over Time

The recent influence of climate change and land subsidence on the water levels and tidal characteristics in the German Bight is documented by regional tide gauge observations. However, in any long time series the chance arises that measurement conditions may change over time. Some of these changes occur instantaneously like the change of the sensor or corrections of the zero-point of the gauge. Other changes occur subtly, such as alterations of the regional morphology and therefore the mode of behavior at the measurement site. We present long-term changes of tidal characteristics in the waterways of the southern German Bight, by detecting abrupt breakpoints and resulting homogenized trends. In order to understand processes of the changes of the tidal characteristics significant trends in the time series for measured and calculated tidal parameters are analyzed.

scholarly journals Innovative Variance Corrected Sen’s Trend Test on Persistent Hydrometeorological Data

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2119
Author(s):  
Wenpeng Wang ◽  
Yuelong Zhu ◽  
Bo Liu ◽  
Yuanfang Chen ◽  
Xu Zhao
Keyword(s):  
Trend Detection ◽  
Trend Test ◽  
Independent Data ◽  
Test Statistic ◽  
Short Term ◽  
Theoretical Derivation ◽  
Stepwise Procedure ◽  
Factual Data ◽  
Over Time

Trend detection in observations helps one to identify anthropogenic forces on natural hydrological and climatic systems. Hydrometeorological data are often persistent over time that deviates from the assumption of independence used by many statistical methods. A recently proposed Sen’s trend test claimed to be free of this problem and thereby received widespread attention. However, both theoretical derivation and stochastic simulation of the current study implies that persistence inflates the trend significance, leading to false trends. To tackle this problem, we incorporate the feature of persistence into the variance of the trend test statistic, whereby an innovative variance-corrected Sen’s trend test is developed. Two theoretical variances of the trend test statistic are newly derived to account for short-term and long-term persistent behavior. The original variance for independent data is also corrected because of its negative bias. A stepwise procedure, including steps to specify the underlying persistent behavior and to test trend with new statistic, is outlined for performing the new test on factual data. Variance-corrected Sen’s trend test can effectively restore the inflated trend significance back to its nominal state. This study may call for the reassessment of published results of the original Sen’s trend test on data with persistence.

Long Term Consistency of Handwriting Grip Kinetics in Adults

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Bassma Ghali ◽  
Khondaker A. Mamun ◽  
Tom Chau
Keyword(s):  
Data Collection ◽  
Grip Force ◽  
Statistical Tests ◽  
Relative Magnitude ◽  
Clinical Applications ◽  
Misclassification Rate ◽  
Second Phase ◽  
Two Phases ◽  
Over Time

While there is growing interest in clinical applications of handwriting grip kinetics, the consistency of these forces over time is not well-understood at present. In this study, we investigated the short- and long-term intra-participant consistency and inter-participant differences in grip kinetics associated with adult signature writing. Grip data were collected from 20 adult participants using a digitizing tablet and an instrumented pen. The first phase of data collection occurred over 10 separate days within a three week period. To ascertain long-term consistency, a second phase of data collection followed, one day per month over several months. In both phases, data were collected three times a day. After pre-processing and feature extraction, nonparametric statistical tests were used to compare the within-participant grip force variation between the two phases. Participant classification based on grip force features was used to determine the relative magnitude of inter-participant versus intra-participant differences. The misclassification rate for the longitudinal data were used as an indication of long term kinetic consistency. Intra-participant analysis revealed significant changes in grip kinetic features between the two phases for many participants. However, the misclassification rate, on average, remained stable, despite different demarcations of training, and testing data. This finding suggests that while signature writing grip forces may evolve over time, inter-participant kinetic differences consistently exceeds within-participant force changes in the long-term. These results bear implications on the collection, modeling and interpretation of grip kinetics in clinical applications.

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