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 Enhancing water levels of degraded, bare, tropical peatland in West Kalimantan, Indonesia: Impacts on CO2 emission from soil respiration

2018 ◽  
Vol 19 (2) ◽  
pp. 472-477
Author(s):  
DWI ASTIANI ◽  
BURHANUDDIN BURHANUDDIN ◽  
EVI GUSMAYANTI ◽  
TRI WIDIASTUTI ◽  
MUHAMMAD J. TAHERZADEH
Keyword(s):  
Soil Respiration ◽  
Co2 Emissions ◽  
Water Table ◽  
Carbon Emissions ◽  
Co2 Emission ◽  
Water Levels ◽  
Small Scale ◽  
West Kalimantan ◽  
Tropical Peatland ◽  
Water Tables

Astiani D, Burhanuddin, Gusmayanti E, Widiastuti T, Taherzadeh MJ. 2018. Enhancing water levels of degraded, bare, tropical peatland in West Kalimantan, Indonesia: Impacts on CO2 emission from soil respiration. Biodiversitas 19: 472-477. The major drivers of deforestation in West Kalimantan have been the development for large or small-scale expansion of agricultural activities; the establishment of oil palm and other plantations; fire; and degradation of forests particularly from industrial logging. Our previous research findings have shown that such activities in affected peatland areas have lowered the water table levels (down to 0.5-1.0 m depths), and have significantly increased CO2 emissions from the peat soils. It has been demonstrated that unmanaged, lowered water tables in peatlands act as one of the main factors inflating soil carbon emissions - an issue that has assumed global significance in recent decades. Regulating peatland water tables has the potential to mitigate degraded peatland carbon emissions as well as improve the hydrological functions for communities who farm the peatlands. However, we are still uncertain exactly how much impact controlled raising of the peatlands water tables will have on reducing soil CO2 emissions. The research described here aimed to mitigate CO2 emissions by raising and regulating water levels on drained peatland to restore and enhance its hydrological functions. The results confirmed that raising the water table significantly decreases CO2 emissions and improves water availability and management for crop production in the coastal peatland of Kubu Raya district, West Kalimantan. Water levels previously at 60cm below the soil surface were regulated to raise the watertable up to just 30 cm below the surface and this reduced peatland carbon emissions by about 49%. However, longer-term monitoring is required to ensure that the hydrological benefits and CO2 mitigation can be sustained.

scholarly journals Wave Climate Associated With Changing Water Level and Ice Cover in Lake Michigan

2021 ◽  
Vol 8 ◽  
Author(s):  
Chenfu Huang ◽  
Longhuan Zhu ◽  
Gangfeng Ma ◽  
Guy A. Meadows ◽  
Pengfei Xue
Keyword(s):  
Climate Change ◽  
Water Level ◽  
Lake Michigan ◽  
Linear Trend ◽  
Ice Cover ◽  
Wave Climate ◽  
Water Levels ◽  
Regional Warming ◽  
Model Simulations

Detailed knowledge of wave climate change is essential for understanding coastal geomorphological processes, ecosystem resilience, the design of offshore and coastal engineering structures and aquaculture systems. In Lake Michigan, the in-situ wave observations suitable for long-term analysis are limited to two offshore MetOcean buoys. Since this distribution is inadequate to fully represent spatial patterns of wave climate across the lake, a series of high-resolution SWAN model simulations were performed for the analysis of long-term wave climate change for the entirety of Lake Michigan from 1979 to 2020. Model results were validated against observations from two offshore buoys and 16 coastal buoys. Linear regression analysis of significant wave height (Hs) (mean, 90th percentile, and 99th percentile) across the entire lake using this 42-year simulation suggests that there is no simple linear trend of long-term changes of Hs for the majority (>90%) of the lake. To address the inadequacy of linear trend analysis used in previous studies, a 10-year trailing moving mean was applied to the Hs statistics to remove seasonal and annual variability, focusing on identifying long-term wave climate change. Model results reveal the regime shifts of Hs that correspond to long-term lake water level changes. Specifically, downward trends of Hs were found in the decade of 1990–2000; low Hs during 2000–2010 coincident with low lake levels; and upward trends of Hs were found during 2010–2020 along with rising water levels. The coherent pattern between the wave climate and the water level was hypothesized to result from changing storm frequency and intensity crossing the lake basin, which influences both waves (instantly through increased wind stress on the surface) and water levels (following, with a lag through precipitation and runoff). Hence, recent water level increases and wave growth were likely associated with increased storminess observed in the Great Lakes. With regional warming, the decrease in ice cover in Lake Michigan (particularly in the northernmost region of the lake) favored the wave growth in the winter due to increased surface wind stress, wind fetch, and wave transmission. Model simulations suggest that the basin-wide Hs can increase significantly during the winter season with projected regional warming and associated decreases in winter ice cover. The recent increases in wave height and water level, along with warming climate and ice reduction, may yield increasing coastal damages such as accelerating coastal erosion.

Mail Survey Response Rates: Their Manipulation and Impact

1977 ◽  
Vol 14 (3) ◽  
pp. 391-395 ◽  
Author(s):  
Michael S. Goodstadt ◽  
Linda Chung ◽  
Reena Kronitz ◽  
Gaynoll Cook
Keyword(s):  
Linear Trend ◽  
Mail Survey ◽  
Response Rates ◽  
Survey Response ◽  
Significant Linear Trend ◽  
Speed Of Response ◽  
Over Time

A study involving 2,416 randomly selected magazine readers indicated that response rates to mail questionnaires were significantly increased by the use of 25¢ premiums, but not by the use of a free-book premium or a free-book reward for responding. Response rates over time showed a very significant linear trend with an additional smaller cubic component. A complex significant (cubic) relationship between speed of response and favorability of expressed opinions reinforced conclusions that the broadest spectrum of opinions is obtained best by maximizing response rates.

Changes over Time in Academic Dishonesty at the Collegiate Level

1995 ◽  
Vol 76 (3) ◽  
pp. 763-768 ◽  
Author(s):  
Shane Spiller ◽  
Deborah F. Crown
Keyword(s):  
Academic Dishonesty ◽  
Linear Trend ◽  
Significant Linear Trend ◽  
Cheating Behavior ◽  
Collegiate Level ◽  
Time Periods ◽  
Changes Over Time ◽  
Over Time

Recent assertions that collegiate cheating has risen dramatically have increased in frequency. We examine the possibility that these assertions are based on comparisons of studies of different behaviors with varied methodologies, and different opportunities to cheat. To assess the increase in cheating we identified a cheating behavior which had been empirically studied consistently from the early 1900s. When the percentages of students who cheated in these studies were compared across time periods, while controlling for methodological differences, no significant linear trend was found.

scholarly journals The role of dynamics in total ozone deviations from their long-term mean over the Northern Hemisphere

1999 ◽  
Vol 17 (2) ◽  
pp. 231-241 ◽  
Author(s):  
K. Petzoldt
Keyword(s):  
Correlation Coefficient ◽  
Northern Hemisphere ◽  
Total Ozone ◽  
Middle Atmosphere ◽  
Linear Trend ◽  
Atmospheric Composition ◽  
Data Set ◽  
Significant Linear Trend ◽  
Circulation Parameters

Abstract. Total ozone anomalies (deviation from the long-term mean) are created by anomalous circulation patterns. The dynamically produced ozone anomalies can be estimated from known circulation parameters in the layer between the tropopause and the middle stratosphere by means of statistics. Satellite observations of ozone anomalies can be compared with those expected from dynamics. Residual negative anomalies may be due to chemical ozone destruction. The statistics are derived from a 14 year data set of TOMS (Total Ozone Mapping Spectrometer January 1979-Dec. 1992) and corresponding 300 hPa geopotential (for the tropopause height) together with 30 hPa temperature (for stratospheric waves) at 60°N. The correlation coefficient for the linear multiple regression between total ozone (dependent variable) and the dynamical parameters (independent variables) is 0.88 for the zonal deviations in the winter of the Northern Hemisphere. Zonal means are also significantly dependent on circulation parameters, besides showing the known negative trend function of total ozone observed by TOMS. The significant linear trend for 60°N is \\sim3 DU/year in the winter months taking into account the dependence on the dynamics between the tropopause region and the mid-stratosphere. The highest correlation coefficient for the monthly mean total ozone anomalies is reached in November with 0.94.Key words. Atmospheric composition and structure (middle atmosphere · composition and chemistry) · Meteorology and atmospheric dynamics (middle atmosphere dynamics).

Self–Esteem among Chinese Cohorts: Its Temporal Trend and Its Relationships with Socioecological Factors, 1993–2016

2020 ◽  
Vol 34 (2) ◽  
pp. 203-214 ◽  
Author(s):  
Liman Man Wai Li ◽  
Wen–Qiao Li ◽  
Dongmei Mei ◽  
Yiheng Wang
Keyword(s):  
Secondary School ◽  
Secondary School Students ◽  
Temporal Change ◽  
Linear Trend ◽  
Self Esteem ◽  
School Students ◽  
Significant Linear Trend ◽  
The Usa ◽  
The Relationship ◽  
Over Time

Self–esteem affects individuals in a variety of psychological processes substantially and extensively. While an increase in self–esteem over time was observed in the USA, different patterns of temporal change in self–esteem were observed in other societies. We analysed the responses ( n = 305 229) collected between 1993 and 2016 from 609 articles to examine the patterns of temporal change in self–esteem in China and its relations with socioecological conditions. Additionally, we explored the patterns in different groups, including secondary school students (158 samples; n = 97 751), college students (427 samples; n = 153 474), and community participants (232 samples; n = 54 004). Some major findings were noted: (i) overall, the level of self–esteem increased over time. However, we also found a significant curvilinear trend in self–esteem with a decline followed by a recent increase; (ii) some evidence for the relationship between socioecological factors and self–esteem was obtained; and (iii) the patterns varied in different cohort groups. Specifically, secondary school students showed a different pattern, in which their self–esteem level did not show a significant linear trend and was not correlated with the examined socioecological factors. The implications on the theories for the relationship between personality characteristics and socioecological conditions were discussed.

scholarly journals Analysis of the variations of measured values in continuous long-term geodetic monitoring

2016 ◽  
Vol 15 (1) ◽  
pp. 11-33
Author(s):  
Jan Vaněček
Keyword(s):  
Harmonic Function ◽  
Function Approximation ◽  
Linear Trend ◽  
Measured Data ◽  
Geodetic Measurement ◽  
Main Method ◽  
Time Period ◽  
Over Time ◽  
Periodic Changes

<pre>A geodetic measurement of shifts and deformations by total station is a well-known and widely used method. There is presented the analysis of the variations over time of the measured values in continuous geodetic monitoring in this paper. There are used measured data from a specific monitoring system of a surface mine in the time period from January 2006 to July 2010 in the analysis.</pre><pre>The aim of the analysis is to describe linear trend and periodic changes in measured data (horizontal direction, zenith angle and slope distance). The main method of the analysis is a linear-harmonic function approximation.</pre>

Alcohol Consumption in Victims of Violence: A Trend Study for the Period 1970–1998

2000 ◽  
Vol 87 (3) ◽  
pp. 803-811 ◽  
Author(s):  
Johannes Kingma
Keyword(s):  
Alcohol Consumption ◽  
Incidence Rate ◽  
Linear Trend ◽  
Incidence Rates ◽  
University Hospital ◽  
Significant Linear Trend ◽  
Male Predominance ◽  
Victims Of Violence ◽  
The University

This 29-yr. retrospective study is about alcohol consumption by victims of violence intentionally injured ( N = 13,048) and general patients unintentionally injured ( N = 296,544) who were treated for their injuries at the Trauma Center of the University Hospital Groningen (The Netherlands) during the period 1970–1998 The incidence rate for general patients with alcohol consumption was statistically significantly greater than the incidence rate of victims of violence with alcohol consumption. A long-term significant linear trend was observed for both types of patients during the 29-yr. period. However, the increase in incidence rate among the general patients with alcohol consumption was four times greater than the increase in incidence rate for the victims of violence with alcohol consumption. Makes predominated in both types of patients (with and without alcohol consumption). The statistically significant highest incidence rates (and male predominance) were found in the age group 20–24 years for both categories of patients.

Communicator Discrepancy, Measurement Delay, and Influence

1969 ◽  
Vol 25 (3) ◽  
pp. 923-928
Author(s):  
Mirza S. Saiyadain
Keyword(s):  
Linear Trend ◽  
Curvilinear Relationship ◽  
Measurement Condition ◽  
Significant Linear Trend ◽  
Opinion Change ◽  
Sleeper Effect ◽  
Delayed Measurement ◽  
Measurement Delay ◽  
Over Time

106 Ss made judgments of numerosity after they were exposed to the judgments of male confederates. There was a curvilinear relationship between communication discrepancy and immediately measured opinion change. The prediction that with delayed measurement retention of the changed opinion would dissipate over time was not significantly supported. A significant linear trend interacted with the curvilinear trend in the immediate measurement condition. These results were interpreted as being consistent with the sleeper-effect phenomenon.

scholarly journals What Factors Affect Intrapartum Maternal Temperature? A Prospective Cohort Study

2012 ◽  
Vol 117 (2) ◽  
pp. 302-308 ◽  
Author(s):  
Michael A. Frölich ◽  
Alice Esame ◽  
Kui Zhang ◽  
Jihua Wu ◽  
John Owen
Keyword(s):  
Body Mass Index ◽  
Cohort Study ◽  
Epidural Analgesia ◽  
Body Mass ◽  
Prospective Cohort Study ◽  
Prospective Cohort ◽  
Linear Trend ◽  
Significant Linear Trend ◽  
Temperature Slope ◽  
Over Time

Background In recent years, several reports have indicated that maternal temperature elevations during labor may also be observed in the absence of an infection. Presumed noninfectious causes of maternal temperature elevations include epidural analgesia, endogenous heat production generated by the contracting uterus, and delivery in an overheated room. To investigate the potential causes of noninfectious maternal temperature changes during labor, we conducted a prospective cohort study in women scheduled for labor induction. Methods We recorded hourly oral temperatures from admission to delivery. We calculated whether temperature changed during labor in 81 women. We then determined if body mass index, and duration of labor, or time from rupture of amniotic sac to delivery, or oxytocin dose, would affect maternal temperature. To evaluate the possible role of epidural analgesia, we compared the temperature slope before and after starting epidural analgesia. Results We observed an overall significant linear trend of temperature over time with an estimated temperature slope of +0.017°C/h (P = 0.0093). Patients with a positive temperature trend had also a significantly longer time from rupture of membranes to delivery (P = 0.0077) and a higher body mass index (P = 0.0067). Epidural analgesia had no effect on the temperature trend. Conclusions In our cohort of patients, there was an overall significant linear trend of temperature over time after correcting for heterogeneity among patients. Temperature increase was associated with higher body mass index values and longer time from rupture of membranes to delivery. Epidural analgesia had no effect on maternal temperature.

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