Spatial and Temporal Changes in Temperature, Precipitation, and Streamflow in the Miyun Reservoir Basin of China

Yan, Tao; Bai, Zhenyao

doi:10.3390/w9020078

Cited by 28 publications

(21 citation statements)

References 57 publications

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“…Of the two methods most commonly used, the parametric and nonparametric methods, the latter has been favored over the former [49]. Among the nonparametric methods, the Mann-Kendall (MK) statistical test [51,52] has been frequently used to quantify the significance of trends in time series [1,23,[45][46][47][48][49][50][53][54][55][56][57][58][59][60]. It is also widely used in environmental science because it is simple, robust, and can cope with missing values and values below a detection limit.…”

Section: Discussionmentioning

confidence: 99%

Precipitation Trends over Slovakia in the Period 1981–2013

Zeleňáková

Vido

Portela

et al. 2017

Water

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Abstract:The objective of this paper was to analyze the temporal and spatial trends in annual and seasonal precipitation in Slovakia utilizing 487 gauging station data collected statewide in the period from 1981 to 2013. The nonparametric Mann-Kendall (MK) statistical test, which has been widely used to assess the significance of trends in hydrological time series, was applied to detect the significant trends. The Theil-Sen (TS) approach was applied to quantify the trend magnitude, and the Sequential Mann-Kendall (SQMK) test was used to detect abrupt temporal trend shifts. In general, precipitation data in the study area have not changed during the last 33 years, and there are no big gaps. However, predominantly increasing trends in precipitation time series were found at most of the gauging stations in Slovakia. The results corroborate previous climatic studies in the area of central Europe. In Slovakia, there is evidence of different rain distribution from the monthly point of view. Decreasing trends were detected in December in the northern part of Slovakia, while the central and southern parts revealed increasing trends. Most of the stations showed increasing summer precipitation trends, especially in July. It is expected that the findings of this comprehensive study of precipitation trends over Slovakia will produce more insights for the understanding of the regional hydrological behavior in Slovakia over the last several decades.

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Section: Discussionmentioning

confidence: 99%

Precipitation Trends over Slovakia in the Period 1981–2013

Zeleňáková

Vido

Portela

et al. 2017

Water

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“…It belongs to the soil order of Alfisols according to the US Soil Taxonomy (Soil Survey Staff, 1999). The mean annual temperature is 5.7°C and the mean annual precipitation is 487 mm, mainly occurring in the 4 mo from June to September (Yan et al, 2017).…”

Section: Methodsmentioning

confidence: 99%

Is the Laser Diffraction Method Reliable for Soil Particle Size Distribution Analysis?

Yang

Wang

Wendroth³

et al. 2019

Soil Science Soc of Amer J

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LDM was evaluated by SPM and SEM for soil PSD determination. LDM significantly overestimated sand and silt but underestimated clay contents compared to SPM. LDM resulted in soil texture class shifts in nearly half of the soil samples in contrast to SPM. Linear conversions were significant for sand and silt but not for clay contents from LDM to SPM. LDM held statistically similar median particle sizes with SEM for PSDs within the clay fraction. The laser diffraction method (LDM) has been increasingly applied for quantifying soil particle size distribution (PSD), owing to its advantages of rapid analysis, high reproducibility, and continuous PSD measurement for a wide range of size fractions. However, some ambiguities exist regarding the comparability of results with those obtained using other classical methods. The objective of the current study was to evaluate LDM‐derived PSDs via comparisons with PSDs obtained with the standard sieve–pipette method (SPM) and from the absolute method of microscopy. A total of 277 soil samples were collected at different soil depths in a typical cropland in the northeast mountainous region of Beijing and analyzed with both SPM and LDM. Due to time and labor constraints, scanning electron microscopy (SEM) was performed on 100 samples randomly selected for the PSDs within the clay fraction withdrawn by SPM. The results manifested on the average 18.9% underestimation of clay content and 25.3% overestimation of silt content by LDM compared to SPM. These disagreements directly caused the shifts of soil texture class in 44.8% of the soil samples. Significant linear regression equations were generated to convert LDM–derived sand and silt contents to SPM–derived ones (p < 0.01). The linear conversions for the clay content were only significant for the calibration samples, but possessed negative coefficients of determination for the validation set. According to SEM, silt‐sized particles were wrongly included in the clay fraction identified by SPM. Eliminating such particles, the clay contents corrected by SEM were significantly lower when assuming the shape of clay particles < 2 µm as plates or discs with constant thickness–diameter ratio of 1/10, and higher when considering the clay particles as spheres for volume calculation, in contrast to those measured by LDM (P < 0.01). Detailed volume‐based PSDs within the clay fraction were further compared between SEM and LDM, revealing dissimilar PSD patterns but statistically similar median particle diameters. These findings suggest the effectiveness of LDM in soil PSD determination. Future work is needed to systematically quantify the impact of other possible factors such as clay mineralogy and refractive index on LDM‐derived PSDs.

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“…In this study, the Mann-Kendall (MK) test, a non-parametric test recommended by the World Meteorological Organization (WMO), was used to detect trends [23][24][25]. The MK test has been widely used for trend detection in hydrological and climatic research since the data does not need to conform to any distribution form, and it allows the missing data [26,27]. In this research, the missing data were filled due to computation of the ET 0 .…”

Section: Trend Analysismentioning

confidence: 99%

Changes of Reference Evapotranspiration and Its Relationship to Dry/Wet Conditions Based on the Aridity Index in the Songnen Grassland, Northeast China

Zhang

Sun

et al. 2017

Water

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Abstract:Reference evapotranspiration (ET 0 ) plays an important role in regional dry/wet conditions. Based on the Food and Agriculture Organization of the United (FAO) Penman-Monteith method and daily climate variables, ET 0 was calculated for 21 stations in and around the Songnen Grassland, northeast China, during 1960China, during -2014. The temporal and spatial variations of ET 0 and precipitation (P) were analyzed in the annual, seasonal, and growing season (from April to October) time series using the Mann-Kendall test, Sen's slope estimator, and linear regression coupled with a break trend analysis. A sensitivity analysis was used to detect the key climate parameter contributing to ET 0 change. By linear regression analysis on the relationship between ET 0 , P, and the aridity index (AI), the role of ET 0 in determining regional wet/dry conditions was analyzed. Results show a higher ET 0 in the southwest and a lower ET 0 in the northeast, but P was opposite to that of ET 0 . Evident decreasing trends of ET 0 in the annual, seasonal, and growing season time series were detected in almost the entire region by the trend analysis methods. For the entire region, the decreasing trend of ET 0 can be linked to the relative humidity and maximum air temperature. The positive contribution of increasing temperature to ET 0 was offset by the effect of the significantly decreasing relative humidity, wind speed, and sunshine duration at the 0.05 level during 1960-2014. In addition, the value of ET 0 was higher in drought years and lower in wet years.

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Spatial and Temporal Changes in Temperature, Precipitation, and Streamflow in the Miyun Reservoir Basin of China

Cited by 28 publications

References 57 publications

Precipitation Trends over Slovakia in the Period 1981–2013

Precipitation Trends over Slovakia in the Period 1981–2013

Is the Laser Diffraction Method Reliable for Soil Particle Size Distribution Analysis?

Changes of Reference Evapotranspiration and Its Relationship to Dry/Wet Conditions Based on the Aridity Index in the Songnen Grassland, Northeast China

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