A Multilayer Soil Moisture Dataset Based on the Gravimetric Method in China and Its Characteristics

Abstract Based on the gravimetric-technique-measured soil relative wetness and the observed soil characteristic parameters from 1992 to 2013 in China, this study derives a user-convenient monthly volumetric soil moisture (SM) dataset from 732 stations for five soil layers (10, 20, 50, 70, and 100 cm). The temporal–spatial variations in SM and its relationship with precipitation (Pr) in different subregions are then explored. The magnitude of SM is relatively large in south China and is low in northwest China, and it generally increases with soil depth in each region. The maximum SM appears in spring and/or autumn and the minimum in summer, and the SM seasonality does not vary as distinctly as that of Pr. For the top three soil layers (10-, 20-, and 50-cm levels), the linear trend analysis indicates an overall increasing SM tendency, and the mean trends (averaged across stations with trends passing a 95% significance level test) are 9.35 × 10−7, 7.37 × 10−3, and 2.45 × 10−3 cm3 cm−3 yr−1, respectively. SM memory depends on the soil depth and regions, and it has longer retention time in the deeper layers. Furthermore, the correlation between SM and antecedent Pr varies with soil depth and lag time. The antecedent Pr anomaly (1 or 2 months in advance) can be used to some extent as a surrogate SM anomaly in most regions except for in arid regions. This result is further demonstrated by the relationships between the SM anomaly and the standardized precipitation index. The current SM dataset can be used in various applications, such as validating satellite-retrieved products and model outputs.

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Evaluation of Drought Stress in Cereal through Probabilistic Modelling of Soil Moisture Dynamics

Water ◽

10.3390/w12092592 ◽

2020 ◽

Vol 12 (9) ◽

pp. 2592 ◽

Cited By ~ 1

Author(s):

María del Pilar Jiménez-Donaire ◽

Juan Vicente Giráldez ◽

Tom Vanwalleghem

Keyword(s):

Soil Moisture ◽

Soil Depth ◽

Standardized Precipitation Index ◽

Early Warning Systems ◽

Agricultural Drought ◽

Annual Precipitation ◽

Drought Indices ◽

Climate Data ◽

Management Tools ◽

The Standardized Precipitation Index

The early and accurate detection of drought episodes is crucial for managing agricultural yield losses and planning adequate policy responses. This study aimed to evaluate the potential of two novel indices, static and dynamic plant water stress, for drought detection and yield prediction. The study was conducted in SW Spain (Córdoba province), covering a 13-year period (2001–2014). The calculation of static and dynamic drought indices was derived from previous ecohydrological work but using a probabilistic simulation of soil moisture content, based on a bucket-type soil water balance, and measured climate data. The results show that both indices satisfactorily detected drought periods occurring in 2005, 2006 and 2012. Both their frequency and length correlated well with annual precipitation, declining exponentially and increasing linearly, respectively. Static and dynamic drought stresses were shown to be highly sensitive to soil depth and annual precipitation, with a complex response, as stress can either increase or decrease as a function of soil depth, depending on the annual precipitation. Finally, the results show that both static and dynamic drought stresses outperform traditional indicators such as the Standardized Precipitation Index (SPI)-3 as predictors of crop yield, and the R2 values are around 0.70, compared to 0.40 for the latter. The results from this study highlight the potential of these new indicators for agricultural drought monitoring and management (e.g., as early warning systems, insurance schemes or water management tools).

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Discovering Trends of Agricultural Drought in Tihama Plain, Yemen : A Preliminary Assessment

Indonesian Journal of Geography ◽

10.22146/ijg.12089 ◽

2017 ◽

Vol 49 (1) ◽

pp. 17 ◽

Cited By ~ 2

Author(s):

Noorazuan Md hashim ◽

Ali Ahmed Dhaif Allah ◽

Azahan Awang

Keyword(s):

Soil Moisture ◽

Agricultural Production ◽

Surface Soil ◽

Standardized Precipitation Index ◽

Water Security ◽

Agricultural Drought ◽

Preliminary Assessment ◽

Soil Layers ◽

The Standardized Precipitation Index ◽

Agricultural Areas

Agricultural drought is characterized by lack of sufficient moisture in the surface soil layers to support crop and forage growth. Indicators of agricultural drought often are precipitation, temperature and soil moisture to measure soil moisture and crop yield. This study aims to assess spatiotemporal of drought in the Tihama Plain, which is one of the most important agricultural areas in Yemen, where contributes about 42% of the total agricultural production in the country. In recent years, the Tihama Plain faced changes in the rainy season, which reflect negatively on agriculture production and water security in the area. In this study the Standardized Precipitation Index (SPI) was used to temporal evaluation of the situation of drought, also it has been used Geographic Information Systems (GIS) in order to show the spatial variability distribution of drought in the study area. The analysis results by SPI-6 showed that the years 1984,1991,2002, 2003,2004,2005,2006 and 2008 were the most affected by drought during the study period 30 years (1980-2010), also show that the year 1991 was the worst years of drought experienced by the study area. Based on the fact that the study area is the most important agricultural areas in Yemen, it is recommended a study the drought and its impact on agricultural crops in the area.

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Different trends between extreme and median surface aerosol extinction coefficients over China inferred from quality controlled visibility data

10.5194/acp-2017-335 ◽

2017 ◽

Author(s):

Jing Li ◽

Chengcai Li ◽

Chunsheng Zhao

Keyword(s):

Northwest China ◽

Positive Trend ◽

Median Surface ◽

Aerosol Extinction ◽

Significance Level ◽

The North ◽

Synoptic Conditions ◽

The Mean ◽

Mean Trend ◽

Year 2000

Abstract. Although the temporal changes of aerosol properties have been widely investigated, the majority focused on the averaged condition without much emphasis on the extremes. However, the latter can be more important in terms of human health and climate change. This study uses a previously validated, quality-controlled visibility dataset to investigate the long-term trends of extreme surface aerosol extinction coefficient (AEC) over China, and compare them with the median trends. Two methods are used to independently evaluate the trends, which arrive at consistent results. The sign of extreme and median trends are generally coherent, whereas their magnitudes show distinct spatial and temporal differences. In the 1980s, an overall positive trend is found throughout China with the extreme trend exceeding the mean trend, except for Northwest China and the North China Plain. In the 1990s, AEC over Northeast and Northwest China starts to decline while the rest of the country still exhibits an increase. The extreme trends continue to dominate in the south while it yields to the mean trend in the north. After year 2000, the extreme trend becomes weaker than the mean trend overall in terms of both the magnitude and significance level. The annual trend can be primarily attributed to winter and fall trends. The results suggest that the decadal changes of pollution in China may be governed by different mechanisms. Synoptic conditions that often result in extreme air quality changes might dominate in the 1980s, whereas emission increase might be the main factor for the 2000s.

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Analysis of Changes in Precipitation and Drought in Aksu River Basin, Northwest China

Advances in Meteorology ◽

10.1155/2015/215840 ◽

2015 ◽

Vol 2015 ◽

pp. 1-15 ◽

Cited By ~ 15

Author(s):

Yuhu Zhang ◽

Wanyuan Cai ◽

Qiuhua Chen ◽

Yunjun Yao ◽

Kaili Liu

Keyword(s):

Meteorological Data ◽

Standardized Precipitation Index ◽

Northwest China ◽

Precipitation Series ◽

Significance Level ◽

Spatiotemporal Trends ◽

Increasing Trend ◽

Almost All ◽

Increasing Trends ◽

Aksu River Basin

The analysis of the spatiotemporal trends of precipitation and drought is relevant for the future development and sustainable management of water resources in a given region. In this study, precipitation and Standardized Precipitation Index (SPI) trends were analyzed through applying linear regression, Mann–Kendall, and Spearman’s Rho tests at the 5% significance level. For this goal, meteorological data from 9 meteorological stations in and around Aksu Basin during the period 1960–2010 was used, and two main annual drought periods were detected (1978-1979 and 1983–1986), while the extremely dry years were recorded in 1975 and 1985 at almost all of the stations. The monthly analysis of precipitation series indicates that all stations had increasing trend in July, October, and December, while both increasing and decreasing trends were found in other months. For the seasonal scale, precipitation series had increasing trends in summer and winter. 33% of the stations had the decreasing trend on precipitation in the spring series, and it was 11% in the autumn. At the same time, the SPI-12 values of all stations had the increasing trend. The significant trends were detected at Aheqi, Baicheng, Keping, and Kuche stations.

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Estimating Regional Soil Moisture Distribution Based on NDVI and Land Surface Temperature Time Series Data in the Upstream of the Heihe River Watershed, Northwest China

Remote Sensing ◽

10.3390/rs12152414 ◽

2020 ◽

Vol 12 (15) ◽

pp. 2414

Author(s):

Xiao Bai ◽

Lanhui Zhang ◽

Chansheng He ◽

Yi Zhu

Keyword(s):

Remote Sensing ◽

Soil Moisture ◽

Land Surface ◽

Regional Scale ◽

Northwest China ◽

Heihe River ◽

Regression Equations ◽

Mountainous Areas ◽

Soil Layers ◽

Temporal And Spatial

Temporal and spatial variability of soil moisture has an important impact on hydrological processes in mountainous areas. Understanding such variability requires soil moisture datasets at multiple temporal and spatial scales. Remote sensing is a very effective method to obtain surface (~5 cm depth) soil moisture at the regional scale but cannot directly measure soil moisture at deep soil layers (>5 cm depth) currently. This study chose the upstream of the Heihe River Watershed in the Qilian Mountain Ranges in Northwest China as the study area to estimate the profile soil moisture (0–70 cm depth) at the regional scale using satellite Vegetation Index (NDVI) and Land Surface Temperature (LST) products. The study area was divided into 31 zones according to the combination of altitude, vegetation and soil type. Long-term in situ soil moisture observation stations were set up at each of the zones. Soil moisture probe, ECH2O, was used to collect soil moisture at five layers (0–10, 10–20, 20–30, 30–50 and 50–70 cm) continuously. Multiple linear regression equations of time series MODIS (Moderate-resolution Imaging Spectroradiometer) NDVI, LST and soil moisture were developed for each of the five soil layers at the 31 zones to estimate the soil moisture (0–70 cm) on a regional scale with a spatial resolution of 1 km2 and a temporal resolution of 16-d from October, 2013 to September, 2016. The correlation coefficient R of the regression equations was between 0.47 and 0.94, the RMSE was 0.03, indicating that the estimation method based on the MODIS NDVI and LST data was suitable and could be applied to alpine mountainous areas with complex topography, soil and vegetation types. The overall pattern of soil moisture spatial distribution indicated that soil moisture was higher in the eastern region than in the western region, and the soil moisture content in the whole study area was 14.5%. The algorithm and results provide novel applications of remote sensing to support soil moisture data acquisition and hydrological research in mountainous areas.

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Drought Monitoring for Washington State: Indicators and Applications

Journal of Hydrometeorology ◽

10.1175/2010jhm1307.1 ◽

2011 ◽

Vol 12 (1) ◽

pp. 66-83 ◽

Cited By ~ 76

Author(s):

Shraddhanand Shukla ◽

Anne C. Steinemann ◽

Dennis P. Lettenmaier

Keyword(s):

Soil Moisture ◽

Land Surface ◽

Snow Water Equivalent ◽

Standardized Precipitation Index ◽

Land Surface Model ◽

Washington State ◽

Drought Monitoring ◽

Surface Model ◽

Drought Conditions ◽

The Standardized Precipitation Index

Abstract A drought monitoring system (DMS) can help to detect and characterize drought conditions and reduce adverse drought impacts. The authors evaluate how a DMS for Washington State, based on a land surface model (LSM), would perform. The LSM represents current soil moisture (SM), snow water equivalent (SWE), and runoff over the state. The DMS incorporates the standardized precipitation index (SPI), standardized runoff index (SRI), and soil moisture percentile (SMP) taken from the LSM. Four historical drought events (1976–77, 1987–89, 2000–01, and 2004–05) are constructed using DMS indicators of SPI/SRI-3, SPI/SRI-6, SPI/SRI-12, SPI/SRI-24, SPI/SRI-36, and SMP, with monthly updates, in each of the state’s 62 Water Resource Inventory Areas (WRIAs). The authors also compare drought triggers based on DMS indicators with the evolution of drought conditions and management decisions during the four droughts. The results show that the DMS would have detected the onset and recovery of drought conditions, in many cases, up to four months before state declarations.

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The effects of stemflow on redistributing precipitation and infiltration around shrubs

Journal of Hydrology and Hydromechanics ◽

10.1515/johh-2017-0043 ◽

2018 ◽

Vol 66 (1) ◽

pp. 79-86 ◽

Cited By ~ 4

Author(s):

Shengqi Jian ◽

Xueli Zhang ◽

Dong Li ◽

Deng Wang ◽

Zening Wu ◽

...

Keyword(s):

Soil Moisture ◽

Root Zone ◽

Soil Depth ◽

Rainfall Threshold ◽

Chinese Loess Plateau ◽

Wetting Front ◽

Deep Soil ◽

Soil Layers ◽

Chinese Loess ◽

Caragana Korshinskii

Abstract The experiments of stemflow of two semiarid shrubs (Caragana korshinskii and Hippophae rhamnoides) and its effect on soil water enhancement were conducted from 1st May to 30th September of 2009-2013 in the Chinese Loess Plateau. Stemflow values in C. korshinskii and H. rhamnoides averaged 6.7% and 2.4% of total rainfall. The rainfall threshold for stemflow generation was 0.5 and 2.5 mm for C. korshinskii and H. rhamnoides. When rainfall was less than 17.0 mm, the funnelling ratios were highly variable, however, stable funnelling ratios were found for rainfall greater than 17.0 mm for C. korshinskii. The funnelling ratios of H. rhamnoides first increased until a threshold value of 10.0 mm and then the funnelling ratios begin stabilize. The wetting front depths in the area around stem was 1.4-6.7 and 1.3-2.9 times deeper than area outside the canopy for C. korshinskii and H. rhamnoides. Soil moisture at soil depth 0-200 cm was 25.6% and 23.4% higher in soil around stem than that outside canopy for C. korshinskii and H. rhamnoides. The wetting front advanced to depths of 120 and 100 cm in the area around stem and to depths of 50 cm in the area outside the canopy for C. korshinskii and H. rhamnoides suggested that more rain water can be conserved into the deep soil layers through shrub stemflow. Soil moisture was enhanced in the area outside the shrub canopy, only when rainfall depth is > 4.7 and 5.1 mm, which is an effective rainfall for the area for C. korshinskii and H. rhamnoides. While for the area around stem of C. korshinskii and H. rhamnoides, the corresponding threshold values are 3.2 and 4.3 mm. These results confirmed that stemflow has a positive effect on soil moisture balance of the root zone and the enhancement in soil moisture of deeper soil layers.

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A Nonparametric Multivariate Multi-Index Drought Monitoring Framework

Journal of Hydrometeorology ◽

10.1175/jhm-d-12-0160.1 ◽

2014 ◽

Vol 15 (1) ◽

pp. 89-101 ◽

Cited By ~ 152

Author(s):

Zengchao Hao ◽

Amir AghaKouchak

Keyword(s):

Soil Moisture ◽

Standardized Precipitation Index ◽

Drought Monitoring ◽

Drought Indices ◽

Multi Index ◽

Additional Information ◽

Indicator Variables ◽

Monitoring Framework ◽

Drought Mitigation ◽

The Standardized Precipitation Index

Abstract Accurate and reliable drought monitoring is essential to drought mitigation efforts and reduction of social vulnerability. A variety of indices, such as the standardized precipitation index (SPI), are used for drought monitoring based on different indicator variables. Because of the complexity of drought phenomena in their causation and impact, drought monitoring based on a single variable may be insufficient for detecting drought conditions in a prompt and reliable manner. This study outlines a multivariate, multi-index drought monitoring framework, namely, the multivariate standardized drought index (MSDI), for describing droughts based on the states of precipitation and soil moisture. In this study, the MSDI is evaluated against U.S. Drought Monitor (USDM) data as well as the commonly used standardized indices for drought monitoring, including detecting drought onset, persistence, and spatial extent across the continental United States. The results indicate that MSDI includes attractive properties, such as higher probability of drought detection, compared to individual precipitation and soil moisture–based drought indices. This study shows that the MSDI leads to drought information generally consistent with the USDM and provides additional information and insights into drought monitoring.

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Effect of tillage erosion on the distribution of CaCO3, phosphorus and the ratio of CaCO3/available phosphorus in the slope landscape

Soil Research ◽

10.1071/sr16077 ◽

2017 ◽

Vol 55 (7) ◽

pp. 630 ◽

Cited By ~ 2

Author(s):

L. Z. Jia ◽

J. H. Zhang ◽

Y. Wang ◽

Z. H. Zhang ◽

B. Li

Keyword(s):

Sichuan Basin ◽

Soil Depth ◽

Distribution Patterns ◽

Available Phosphorus ◽

Soil Layers ◽

Mixing Effect ◽

The Sichuan Basin ◽

The Mean ◽

Tillage Erosion ◽

Topsoil Layer

Little is known about the effect of tillage erosion on the distribution of CaCO3, phosphorus and changes in the ratio of CaCO3/available phosphorus (AP) in the hillslope landscape. The aims of the present study were to elucidate the mechanisms underlying changes in CaCO3 and AP concentrations induced by tillage erosion along slope transects and to reconstruct the historical changes in CaCO3 in soil layers at different landscape positions. Two adjacent slopes were selected from the Sichuan Basin, China, one with downslope tillage (Slope 1) and the other with upslope tillage (Slope 2) for 29 years. Then, consecutive downslope tillage by hoeing was applied five and 20 times on Slope 1. Under normal tillage (both downslope and upslope) conditions, CaCO3 concentrations increased exponentially with soil depth. However, the mixing effect of consecutive tillage (five and 20 tills) changed the vertical CaCO3 distribution patterns. For downslope tillage, the topsoil layer CaCO3 concentration was significantly lower at the toeslope than at other slope positions, but there were no significant differences between toeslope and other slope positions for upslope tillage. Consecutive tillage with five and 20 tills increased CaCO3 concentrations in the topsoil layer by 27.7% and 30.8% respectively compared with downslope tillage, but AP concentrations decreased by 26.1% and 29.0% respectively. Under normal tillage, AP concentrations decreased with increasing CaCO3 concentrations due to the adsorption and precipitation of AP by CaCO3, but this relationship disappeared after consecutive tillage. After consecutive tillage with five and 20 tills, the mean CaCO3/AP ratios of the topsoil layer were 93.5% and 88.4% greater than those for downslope tillage respectively, whereas there were no significant differences between downslope and upslope tillage. In conclusion, tillage is a process of CaCO3 replenishment and AP dilution in the surface layer of soil derived from carbonate-rich bedrocks.

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CORRELATION BETWEEN EVAPORATION FROM BELLANI PLATES AND EVAPOTRANSPIRATION FROM ORCHARDS

Canadian Journal of Plant Science ◽

10.4141/cjps65-021 ◽

1965 ◽

Vol 45 (2) ◽

pp. 132-138 ◽

Cited By ~ 2

Author(s):

H. C. Korven ◽

J. C. Wilcox

Keyword(s):

Soil Moisture ◽

Balance Sheet ◽

Gravimetric Method ◽

Sprinkler Irrigation ◽

The Other ◽

Research Station ◽

The Common ◽

The Mean ◽

Positive Correlations ◽

Practical Field

The balance sheet method, keeping an account of evapotranspiration (estimated from evaporation as measured by Bellani plates) and rainfall, was used for scheduling irrigations on a practical field basis on five orchards in Summerland, B.C. Four of the orchards were on the Research Station and the other on a nearby grower’s orchard. Undertree sprinkler irrigation with 12-hour sets, the common method in the Okanagan Valley, was used. Soil moisture deficits were measured by the gravimetric method and estimated from the balance sheet records. Highly significant positive correlations were obtained between the measured and the estimated deficits. The standard error of regression was high, about 20% of the mean. In spite of this, the balance sheet method proved to be quite satisfactory for use in practical scheduling of irrigation in orchards.

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