scholarly journals A revision of the Combined Drought Indicator (CDI) as part of the European Drought Observatory (EDO)

2020 ◽  
Author(s):  
Carmelo Cammalleri ◽  
Carolina Arias-Muñoz ◽  
Paulo Barbosa ◽  
Alfred de Jager ◽  
Diego Magni ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Deficit ◽  
Early Warning ◽  
Drought Monitoring ◽  
Cascade Process ◽  
Soil Water Deficit ◽  
Temporal Consistency ◽  
Current Version ◽  
Modelling Framework ◽  
Operational Application

Abstract. Building on almost ten years of expertise and operational application of the Combined Drought Indicator (CDI), which is operationally implemented within the European Commission’s European Drought Observatory (EDO) for the purposes of early warning and monitoring of agricultural droughts in Europe, this paper proposes a revised version of the index. The CDI conceptualizes drought as a cascade process, where a precipitation shortage (WATCH stage) develops into a soil water deficit (WARNING stage), which in turn leads to stress for vegetation (ALERT stage). The main goal of the revised CDI proposed here, is to improve the indicator’s performance for those events that are currently not reliably represented, without drastically altering the modelling framework. This is achieved by means of two main modifications: (a) use of the previously occurring CDI value to improve the temporal consistency of the timeseries, (b) introduction of two temporary classes – namely, soil moisture and vegetation greenness – to avoid brief discontinuities in a stage. The efficacy of the modifications is tested by comparing the performances of the revised and currently implemented versions of the indicator, for actual drought events in Europe during the last 20 years. The revised CDI reliably reproduces the evolution of major droughts, out-performing the current version of the indicator, especially for long-lasting events. Since the revised CDI does not need supplementary input datasets, it is suitable for operational implementation within the EDO drought monitoring system.

scholarly journals A revision of the Combined Drought Indicator (CDI) used in the European Drought Observatory (EDO)

2021 ◽  
Vol 21 (2) ◽  
pp. 481-495
Author(s):  
Carmelo Cammalleri ◽  
Carolina Arias-Muñoz ◽  
Paulo Barbosa ◽  
Alfred de Jager ◽  
Diego Magni ◽  
...  
Keyword(s):  
Time Series ◽  
Soil Moisture ◽  
Conceptual Framework ◽  
Early Warning ◽  
Drought Monitoring ◽  
Cascade Process ◽  
Soil Water Deficit ◽  
Temporal Consistency ◽  
Current Version ◽  
Operational Application

Abstract. Building on almost 10 years of expertise and operational application of the Combined Drought Indicator (CDI), which is implemented within the European Commission's European Drought Observatory (EDO) for the purposes of early warning and monitoring of agricultural droughts in Europe, this paper proposes a revised version of the index. The CDI conceptualizes drought as a cascade process, where a precipitation shortage (WATCH stage) develops into a soil water deficit (WARNING stage), which in turn leads to stress for vegetation (ALERT stage). The main goal of the revised CDI proposed here is to improve the indicator's performance for those events that are currently not reliably represented, without altering either the modelling conceptual framework or the required input datasets. This is achieved by means of two main modifications: (a) use of the previously occurring CDI value to improve the temporal consistency of the time series and (b) introduction of two temporary classes – namely TEMPORARY RECOVERY for soil moisture and vegetation greenness, respectively – to avoid brief discontinuities in a stage. The efficacy of the modifications is tested by comparing the performances of the revised and currently implemented versions of the indicator for actual drought events in Europe during the last 20 years. The revised CDI reliably reproduces the evolution of major droughts, outperforming the current version of the indicator, especially for long-lasting events, and reducing the overall temporal inconsistencies in stage sequencing of about 70 %. Since the revised CDI does not need supplementary input datasets, it is suitable for operational implementation within the EDO drought monitoring system.

scholarly journals Assessment of the SMAP-Derived Soil Water Deficit Index (SWDI-SMAP) as an Agricultural Drought Index in China

2018 ◽  
Vol 10 (8) ◽  
pp. 1302 ◽  
Author(s):  
Jueying Bai ◽  
Qian Cui ◽  
Deqing Chen ◽  
Haiwei Yu ◽  
Xudong Mao ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Deficit ◽  
Microwave Remote Sensing ◽  
Agricultural Drought ◽  
Drought Monitoring ◽  
In Situ Observation ◽  
Soil Water Deficit ◽  
The South ◽  
The North

China is frequently subjected to local and regional drought disasters, and thus, drought monitoring is vital. Drought assessments based on available surface soil moisture (SM) can account for soil water deficit directly. Microwave remote sensing techniques enable the estimation of global SM with a high temporal resolution. At present, the evaluation of Soil Moisture Active Passive (SMAP) SM products is inadequate, and L-band microwave data have not been applied to agricultural drought monitoring throughout China. In this study, first, we provide a pivotal evaluation of the SMAP L3 radiometer-derived SM product using in situ observation data throughout China, to assist in subsequent drought assessment, and then the SMAP-Derived Soil Water Deficit Index (SWDI-SMAP) is compared with the atmospheric water deficit (AWD) and vegetation health index (VHI). It is found that the SMAP can obtain SM with relatively high accuracy and the SWDI-SMAP has a good overall performance on drought monitoring. Relatively good performance of SWDI-SMAP is shown, except in some mountain regions; the SWDI-SMAP generally performs better in the north than in the south for less dry bias, although better performance of SMAP SM based on the R is shown in the south than in the north; differences between the SWDI-SMAP and VHI are mainly shown in areas without vegetation or those containing drought-resistant plants. In summary, the SWDI-SMAP shows great application potential in drought monitoring.

scholarly journals Satellite Soil Moisture for Agricultural Drought Monitoring: Assessment of SMAP-Derived Soil Water Deficit Index in Xiang River Basin, China

2019 ◽  
Vol 11 (3) ◽  
pp. 362 ◽  
Author(s):  
Qian Zhu ◽  
Yulin Luo ◽  
Yue-Ping Xu ◽  
Ye Tian ◽  
Tiantian Yang
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Deficit ◽  
River Basin ◽  
Probability Of Detection ◽  
Agricultural Drought ◽  
Drought Monitoring ◽  
Soil Water Deficit ◽  
R Value ◽  
Xiang River

Agricultural drought can have long-lasting and harmful impacts on both the ecosystem and economy. Therefore, it is important to monitor and predict agricultural drought accurately. Soil moisture is the key variable to define the agricultural drought index. However, in situ soil moisture observations are inaccessible in many areas of the world. Remote sensing techniques enrich the surface soil moisture observations at different tempo-spatial resolutions. In this study, the Level 2 L-band radiometer soil moisture dataset was used to estimate the Soil Water Deficit Index (SWDI). The Soil Moisture Active Passive (SMAP) dataset was evaluated with the soil moisture dataset obtained from the China Land Soil Moisture Data Assimilation System (CLSMDAS). The SMAP-derived SWDI (SMAP_SWDI) was compared with the atmospheric water deficit (AWD) calculated with precipitation and evapotranspiration from meteorological stations. Drought monitoring and comparison were accomplished at a weekly scale for the growing season (April to November) from 2015 to 2017. The results were as follows: (1) in terms of Pearson correlation coefficients (R-value) between SMAP and CLSMDAS, around 70% performed well and only 10% performed poorly at the grid scale, and the R-value was 0.62 for the whole basin; (2) severe droughts mainly occurred from mid-June to the end of September from 2015 to 2017; (3) severe droughts were detected in the southern and northeastern Xiang River Basin in mid-May of 2015, and in the northern basin in early August of 2016 and end of November 2017; (4) the values of percentage of drought weeks gradually decreased from 2015 to 2017, and increased from the northeast to the southwest of the basin in 2015 and 2016; and (5) the average value of R and probability of detection between SMAP_SWDI and AWD were 0.6 and 0.79, respectively. These results show SMAP has acceptable accuracy and good performance for drought monitoring in the Xiang River Basin.

Satellite soil moisture for agricultural drought monitoring: Assessment of the SMOS derived Soil Water Deficit Index

2016 ◽  
Vol 177 ◽  
pp. 277-286 ◽  
Author(s):  
J. Martínez-Fernández ◽  
A. González-Zamora ◽  
N. Sánchez ◽  
A. Gumuzzio ◽  
C.M. Herrero-Jiménez
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Deficit ◽  
Agricultural Drought ◽  
Drought Monitoring ◽  
Soil Water Deficit

Soybean Irrigation Initiation in Mississippi: Yield, Soil Moisture, and Economic Response

2019 ◽  
Vol 35 (1) ◽  
pp. 39-50
Author(s):  
H. C. Pringle, III ◽  
L. L. Falconer ◽  
D. K. Fisher ◽  
L. J. Krutz
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Soil Water ◽  
Water Deficit ◽  
Mississippi Delta ◽  
Soil Water Potential ◽  
Irrigation Scheduling ◽  
Silty Clay ◽  
Soil Water Deficit ◽  
Soybean Yield

Abstract. Irrigated acreage is expanding and groundwater supplies are decreasing in the Mississippi Delta. Efficient irrigation scheduling of soybean [ (L.) Merr] will aid in conservation efforts to sustain groundwater resources. The objective of this study was to develop irrigation initiation recommendations for soybean grown on Mississippi Delta soils. Field studies were conducted on a deep silty clay (SiC) in 2012, 2013, 2014, and 2015 and on a deep silty clay loam (SiCL) and deep silt loam (SiL) or loam (L) soil in 2013, 2014, and 2015. Irrigation was initiated multiple times during the growing season and soybean yield and net return were determined to evaluate the effectiveness of each initiation timing. Growth stage, soil water potential (SWP), and soil water deficit (SWD) were compared at these initiation timings to determine which parameter or combination of parameters consistently predicted the resulting greatest yields and net returns. Stress conditions that reduce yield can occur at any time from late vegetative stages to full seed on these deep soils. The wide range of trigger values found for SWP and SWD to increase yields in different years emphasizes the complexity of irrigation scheduling. Monitoring soil moisture by itself or use of a single trigger value is not sufficient to optimize irrigation scheduling to maximize soybean yield with the least amount of water every year on these soils. Monitoring one or more parameters (e.g., leaf water potential, canopy temperature, air temperature, humidity, solar radiation, and wind) is needed in conjunction with soil moisture to directly or indirectly quantify the abiotic stresses on the plant to better define when a yield reducing stress is occurring. Keywords: Irrigation initiation, Irrigation scheduling, Soil water deficit, Soil water potential, Soybean, Water conservation.

A modified soil water deficit index (MSWDI) for agricultural drought monitoring: Case study of Songnen Plain, China

2017 ◽  
Vol 194 ◽  
pp. 125-138 ◽  
Author(s):  
Huicai Yang ◽  
Huixiao Wang ◽  
Guobin Fu ◽  
Haiming Yan ◽  
Panpan Zhao ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Deficit ◽  
Agricultural Drought ◽  
Drought Monitoring ◽  
Soil Water Deficit ◽  
Songnen Plain ◽  
Modified Soil

scholarly journals Sustainable irrigation based on co-regulation of soil water supply and atmospheric evaporative demand

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jingwen Zhang ◽  
Kaiyu Guan ◽  
Bin Peng ◽  
Ming Pan ◽  
Wang Zhou ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Supply ◽  
Soil Water ◽  
Water Deficit ◽  
Irrigation Water ◽  
Crop Yields ◽  
Water Productivity ◽  
Soil Water Deficit ◽  
Irrigation Scheme ◽  
Irrigation Water Use

AbstractIrrigation is an important adaptation to reduce crop yield loss due to water stress from both soil water deficit (low soil moisture) and atmospheric aridity (high vapor pressure deficit, VPD). Traditionally, irrigation has primarily focused on soil water deficit. Observational evidence demonstrates that stomatal conductance is co-regulated by soil moisture and VPD from water supply and demand aspects. Here we use a validated hydraulically-driven ecosystem model to reproduce the co-regulation pattern. Specifically, we propose a plant-centric irrigation scheme considering water supply-demand dynamics (SDD), and compare it with soil-moisture-based irrigation scheme (management allowable depletion, MAD) for continuous maize cropping systems in Nebraska, United States. We find that, under current climate conditions, the plant-centric SDD irrigation scheme combining soil moisture and VPD, could significantly reduce irrigation water use (−24.0%) while maintaining crop yields, and increase economic profits (+11.2%) and irrigation water productivity (+25.2%) compared with MAD, thus SDD could significantly improve water sustainability.

scholarly journals Effects of revegetation on soil moisture under different precipitation gradients in the Loess Plateau, China

2016 ◽  
Vol 48 (5) ◽  
pp. 1378-1390 ◽  
Author(s):  
Fei Tian ◽  
Xiaoming Feng ◽  
Lu Zhang ◽  
Bojie Fu ◽  
Shuai Wang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Deficit ◽  
Loess Plateau ◽  
Large Scale ◽  
Tree Planting ◽  
Mean Annual Precipitation ◽  
Soil Water Deficit ◽  
The Loess Plateau ◽  
Soil Desiccation

Revegetation can alter catchment water balance and result in soil desiccation. Large-scale revegetation took place in the Loess Plateau of China to control soil erosion and improve environmental conditions. However, the dynamic nature of soil moisture in response to revegetation under different climatic conditions is still unclear mainly due to lack of long-term in situ observations. To overcome this challenge, a biophysically based ecohydrological model (WAVES) was used to examine the effects of revegetation on soil moisture. Results showed that trees consume more water (100% of precipitation) than shrub (97.6%) and grass (98.3%), and therefore are more likely to result in soil desiccation. No runoff occurred under the tree scenario, while for shrub and grass, runoff accounted for 2.4% and 1.7% of precipitation, respectively. In areas with mean annual precipitation (MAP) less than 400 mm, tree planting resulted in soil water deficit, while in areas with MAP exceeding 600 mm, no soil water deficit occurred. Within this MAP range (400 < MAP < 600 mm), this could lead to soil water deficit during dry years. Extending this analysis to the entire Loess Plateau, 40% of the region will face reduced soil moisture when converting cropland to trees.

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