Soil moisture as an essential component for delineating and forecasting agricultural rather than meteorological drought

Abstract. Drought is a natural hazard that occurs at many temporal and spatial scales and has severe environmental and socioeconomic impacts across the globe. The impacts of drought change as drought evolves from precipitation deficits to deficits in soil moisture or streamflow. Here, we quantified the time taken for drought to propagate from meteorological drought to soil moisture drought and from meteorological drought to hydrological drought. We did this by cross-correlating the Standardized Precipitation Index (SPI) against standardized indices (SIs) of soil moisture, runoff, and streamflow from an ensemble of global hydrological models (GHMs) forced by a consistent meteorological dataset. Drought propagation is strongly related to climate types, occurring at sub-seasonal timescales in tropical climates and at up to multi-annual timescales in continental and arid climates. Winter droughts are usually related to longer SPI accumulation periods than summer droughts, especially in continental and tropical savanna climates. The difference between the seasons is likely due to winter snow cover in the former and distinct wet and dry seasons in the latter. Model structure appears to play an important role in model variability, as drought propagation to soil moisture drought is slower in land surface models (LSMs) than in global hydrological models, but propagation to hydrological drought is faster in land surface models than in global hydrological models. The propagation time from SPI to hydrological drought in the models was evaluated against observed data at 127 in situ streamflow stations. On average, errors between observed and modeled drought propagation timescales are small and the model ensemble mean is preferred over the use of a single model. Nevertheless, there is ample opportunity for improvement as substantial differences in drought propagation are found at 10 % of the study sites. A better understanding and representation of drought propagation in models may help improve seasonal drought forecasting as well as constrain drought variability under future climate scenarios.

Download Full-text

Commonly Used Drought Indices as Indicators of Soil Moisture in China

Journal of Hydrometeorology ◽

10.1175/jhm-d-14-0076.1 ◽

2015 ◽

Vol 16 (3) ◽

pp. 1397-1408 ◽

Cited By ~ 43

Author(s):

Hongshuo Wang ◽

Jeffrey C. Rogers ◽

Darla K. Munroe

Keyword(s):

Soil Moisture ◽

Time Scales ◽

Standardized Precipitation Index ◽

Meteorological Drought ◽

Severity Index ◽

Agricultural Drought ◽

Weather Data ◽

Drought Indices ◽

Drought Severity ◽

Better Than

Abstract Soil moisture shortages adversely affecting agriculture are significantly associated with meteorological drought. Because of limited soil moisture observations with which to monitor agricultural drought, characterizing soil moisture using drought indices is of great significance. The relationship between commonly used drought indices and soil moisture is examined here using Chinese surface weather data and calculated station-based drought indices. Outside of northeastern China, surface soil moisture is more affected by drought indices having shorter time scales while deep-layer soil moisture is more related on longer index time scales. Multiscalar drought indices work better than drought indices from two-layer bucket models. The standardized precipitation evapotranspiration index (SPEI) works similarly or better than the standardized precipitation index (SPI) in characterizing soil moisture at different soil layers. In most stations in China, the Z index has a higher correlation with soil moisture at 0–5 cm than the Palmer drought severity index (PDSI), which in turn has a higher correlation with soil moisture at 90–100-cm depth than the Z index. Soil bulk density and soil organic carbon density are the two main soil properties affecting the spatial variations of the soil moisture–drought indices relationship. The study may facilitate agriculture drought monitoring with commonly used drought indices calculated from weather station data.

Download Full-text

Can multi-scalar meteorological drought indices detect soil moisture droughts? A study of Indian regions

Hydrological Sciences Journal ◽

10.1080/02626667.2021.1942475 ◽

2021 ◽

Author(s):

Prabir Kumar Das ◽

Sk Mohinuddin ◽

Subrata Midya ◽

Dilip Kumar Das ◽

Richa Sharma ◽

...

Keyword(s):

Soil Moisture ◽

Meteorological Drought ◽

Drought Indices

Download Full-text

Meteorological drought in the Miño-Limia-Sil hydrographic demarcation: The role of atmospheric drivers

10.5194/nhess-2019-314 ◽

2019 ◽

Author(s):

Rogert Sorí ◽

Marta Vázquez ◽

Milica Stojanovic ◽

Raquel Nieto ◽

Margarida Liberato ◽

...

Keyword(s):

Soil Moisture ◽

Iberian Peninsula ◽

Atmospheric Circulation ◽

Root Zone ◽

Meteorological Drought ◽

The Arctic ◽

Regional Patterns ◽

Runoff Change ◽

Drought Conditions ◽

Dry And Wet Conditions

Abstract. Drought is one of the main natural hazards because of its environmental, economic, and social impacts. Therefore, its study, monitoring and prediction for small regions, countries, or whole continents are challenging. In this work, the meteorological droughts affecting the Miño-Limia-Sil Hydrographic Demarcation (MLSHD) in the northwestern Iberian Peninsula during the period of 1980–2017 were identified. For this purpose, and to assess the combined effects of temperature and precipitation on drought conditions, the Standardised Precipitation-Evapotranspiration Index (SPEI) was utilised. During the study period there was no trend in the series of SPEI at the temporal scale of 1 mo (SPEI1); however, the number of drought episodes and their severity have been increasing historically, but this metric was not statistically significant. Particular emphasis was given to investigating atmospheric circulation as a driver of different drought conditions. To this aim, a daily weather type classification was utilised for the entire Iberian Peninsula. The results showed that atmospheric circulation from the southwest, west, and northwest were directly related to dry and wet conditions in the MLSHD during the entire climatological year. Contrastingly, weather types imposing atmospheric circulation from the northeast, east, and southeast and pure anticyclonic circulation were negatively correlated with the SPEI1. In this sense, the major teleconnection atmospheric patterns related to dry/wet conditions were the Arctic Oscillation, Scandinavian Pattern, and North Atlantic Oscillation. Dry and wet conditions according to the SPEI at shorter temporal scales were closely related to the soil moisture in the root zone, and also strongly influenced the streamflow of the Miño and Limia rivers, especially during the rainy season. However, a direct relationship between soil moisture and streamflow was also observed when dry/wet conditions accumulated for more than 1 y. We concluded that regional patterns of land-use change and moisture recycling are important to consider in explaining runoff change, integrating land and water management, and informing water governance.

Download Full-text

Comparison of Meteorological and Agricultural Drought Indicators across Ethiopia

10.20944/preprints201908.0020.v1 ◽

2019 ◽

Author(s):

Dawit Teweldebirhan Tsige ◽

Venkatesh Uddameri ◽

Farhang Forghanparast ◽

Elma Hernandez ◽

Stephen Ekwaro-Osire

Keyword(s):

Soil Moisture ◽

Meteorological Drought ◽

Evaluation Framework ◽

Agricultural Drought ◽

Hydrologic Processes ◽

Preparedness Planning ◽

Drought Indicators ◽

Drought Preparedness ◽

Seasonal Droughts ◽

Meteorological Droughts

Meteorological drought indicators are commonly used for agricultural drought contingency planning in Ethiopia. Agricultural droughts arise due to soil moisture deficits. While these deficits may be caused by meteorological droughts, the timing and duration of agricultural droughts need not coincide with the onset of meteorological droughts due to soil moisture buffering. Similarly, agricultural droughts can persist even after the cessation of meteorological droughts due to delayed hydrologic processes. Understanding the relationship between meteorological and agricultural droughts is therefore crucial. An evaluation framework was developed to compare meteorological and agricultural droughts using a suite of exploratory and confirmatory tools. Receiver operator characteristics (ROC) was used to understand the covariation of meteorological and agricultural droughts. Comparisons were carried out between SPI-2, SPEI-2 and Palmer Z-index to assess intra-seasonal droughts and between SPI-6, SPEI-6 and PDSI for full-season evaluations. SPI was seen to correlate well with selected agricultural drought indicators but did not explain all the variability noted in agricultural droughts. The relationships between meteorological and agricultural droughts exhibited spatial variability which varied across indicators. SPI is better suited to predict non-agricultural drought states more so than agricultural drought states. Differences between agricultural and meteorological droughts must be accounted for better drought-preparedness planning.

Download Full-text

Drought in the Twenty-First Century in a Water-Rich Region: Modeling Study of the Wabash River Watershed, USA

Water ◽

10.3390/w12010181 ◽

2020 ◽

Vol 12 (1) ◽

pp. 181 ◽

Cited By ~ 1

Author(s):

Jennifer R. Dierauer ◽

Chen Zhu

Keyword(s):

Climate Change ◽

Soil Moisture ◽

Climate Warming ◽

Meteorological Drought ◽

Hydrological Drought ◽

First Century ◽

Drought Risk ◽

Wabash River ◽

The Past ◽

Twenty First Century

Climate change is expected to alter drought regimes across North America throughout the twenty-first century, and, consequently, future drought risk may not resemble the past. To explore the implications of nonstationary drought risk, this study combined a calibrated, regional-scale hydrological model with statistically downscaled climate projections and standardized drought indices to identify intra-annual patterns in the response of meteorological, soil moisture, and hydrological drought to climate change. We focus on a historically water-rich, highly agricultural watershed in the US Midwest—the Wabash River Basin. The results show likely increases in the frequency of soil moisture and hydrological drought, despite minimal changes in the frequency of meteorological drought. We use multiple linear regression models to interpret these results in the context of climate warming and show that increasing temperatures amplify soil moisture and hydrological drought, with the same amount of precipitation yielding significantly lower soil moisture and significantly lower runoff in the future than in the past. The novel methodology presented in this study can be transferred to other regions and used to understand how the relationship between meteorological drought and soil moisture/hydrological drought will change under continued climate warming.

Download Full-text

Potential of Pan-European Seasonal Hydrometeorological Drought Forecasts Obtained from a Multihazard Early Warning System

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-18-0196.1 ◽

2020 ◽

Vol 101 (4) ◽

pp. E368-E393 ◽

Cited By ~ 6

Author(s):

Samuel Jonson Sutanto ◽

Henny A. J. Van Lanen ◽

Fredrik Wetterhall ◽

Xavier Llort

Keyword(s):

Soil Moisture ◽

Early Warning ◽

Water Cycle ◽

Warning System ◽

Meteorological Drought ◽

Early Warning Systems ◽

Drought Indices ◽

Drought Forecasting ◽

Wide Range ◽

Drought Early Warning

Abstract Drought early warning systems (DEWS) have been developed in several countries in response to high socioeconomic losses caused by droughts. In Europe, the European Drought Observatory (EDO) monitors the ongoing drought and forecasts soil moisture anomalies up to 7 days ahead and meteorological drought up to 3 months ahead. However, end users managing water resources often require hydrological drought warning several months in advance. To answer this challenge, a seasonal pan-European DEWS has been developed and has been running in a preoperational mode since mid-2018 under the EU-funded Enhancing Emergency Management and Response to Extreme Weather and Climate Events (ANYWHERE) project. The ANYWHERE DEWS (AD-EWS) is different than other operational DEWS in the sense that the AD-EWS provides a wide range of seasonal hydrometeorological drought forecasting products in addition to meteorological drought, that is, a broad suite of drought indices that covers all water cycle components (drought in precipitation, soil moisture, runoff, discharge, and groundwater). The ability of the AD-EWS to provide seasonal drought predictions in high spatial resolution (5 km × 5 km) and its diverse products mark the AD-EWS as a preoperational drought forecasting system that can serve a broad range of different users’ needs in Europe. This paper introduces the AD-EWS and shows some examples of different drought forecasting products, the drought forecast score, and some examples of a user-driven assessment of forecast trust levels.

Download Full-text

Subseasonal Meteorological Drought Development over the Central United States during Spring

Journal of Climate ◽

10.1175/jcli-d-21-0435.1 ◽

2021 ◽

pp. 1-64

Keyword(s):

Soil Moisture ◽

Root Zone ◽

Meteorological Drought ◽

Individual Case ◽

Reanalysis Data ◽

Late Spring ◽

Evaporative Demand ◽

Near Surface ◽

Divergent Flow ◽

Central United States

Abstract Diagnosis of rapidly developing springtime droughts in the central U.S. has mostly been made via numerous individual case studies rather than in an aggregate sense. This study investigates common aspects of subseasonal “meteorological drought” evolution, here defined as persistent precipitation minus evapotranspiration (P-ET) deficits, revealed in early (April 1-May 15) and late (May 16-June 30) spring composites of 5-day running mean JRA-55 reanalysis data for three different central U.S. regions during 1958-2018. On average, these droughts are initiated by a quasi-stationary Rossby wave packet (RWP), propagating from the western North Pacific, which arises about a week prior to drought onset. The RWP is related to a persistent ridge west of the incipient drought region and strong subsidence over it. This subsidence is associated with low-level divergent flow that dries the atmosphere and suppresses precipitation for roughly 1-2 weeks, and generally has a greater impact on the moisture budget than does reduced poleward moisture transport. The resulting “dynamically driven” evaporative demand corresponds to a rapid drying of the root-zone soil moisture, which decreases ∼40 percentiles within ∼10 days. Anomalous near-surface warmth develops only after P-ET deficit onset, as does anomalously low soil moisture that then lingers a month or more, especially in late spring. The horizontal scale of the RWPs, and of the related drought anomalies, decreases from early to late spring, consistent with the climatological change in the Pacific Rossby waveguide. Finally, while this composite analysis is based upon strong, persistent P-ET deficits, it still appears to capture much of the springtime development of so-called “flash droughts” as well.

Download Full-text

Identifying dominant drivers of northern European wildfires

10.5194/egusphere-egu21-11524 ◽

2021 ◽

Author(s):

Sigrid Joergensen Bakke ◽

Niko Wanders ◽

Karin van der Wiel ◽

Monica Ionita ◽

Lena Merete Tallaksen

Keyword(s):

Soil Moisture ◽

Global Climate ◽

Meteorological Drought ◽

Terrestrial Ecosystems ◽

Data Driven ◽

Statistical Dependence ◽

Burned Area ◽

Explanatory Variables ◽

Physically Based ◽

Area Product

Wildfires are recurrent natural hazards that affect terrestrial ecosystems, the carbon cycle, climate and society. An ignition can lead to a wildfire when there is biomass available for burning, typically in combination with dry and windy conditions. Wildfires are regarded as compound events defined as &#8220;an extreme impact that depends on multiple statistically dependent variables or events&#8221; [1], and dominant drivers include a combination of various meteorological, hydrological and biological conditions. More specifically, wildfires can be regarded preconditioned hazards [2] because the combination of drivers can cause the hazard only in the presence of available and burnable biomass (precondition). The availability of burnable biomass is itself driven by conditions such as soil moisture, temperature, humidity, precipitation, etc. Identifying a selection of dominant controls and their statistical dependence, can ultimately improve predictions and projections of wildfires in both current and future climate. In this study, we apply a data-driven bottom-up statistical learning approach (including random forest and logistic regression) to identify dominant factors determining burned area over northern Europe. Potential explanatory variables include temperature, precipitation, wind, soil moisture and vegetation cover, as well as meteorological drought, soil moisture drought and greenness indices. A monthly 2001-2020 burned area product derived from satellite observations is used as target variable, and multiple hydrometeorological and vegetation metrics stemming from the ERA5 reanalysis and observational datasets (e.g. EOBS) are tested as potential predictors. The derived relationships between wildfires and its compound drivers will further be used to assess the potential changes in such a combination of factors under different climate scenarios using large-ensemble global climate simulations and hydrological models. This new framework will allow us to better quantify the changes in potential wildfire risk in a changing climate using a combination of data driven and physically based models.[1] Leonard et al., 2014:&#160;https://doi.org/10.1002/wcc.252 [2] Zscheischler et al., 2020: https://doi.org/10.1038/s43017-020-0060-z

Download Full-text

Comparison of Meteorological- and Agriculture-Related Drought Indicators across Ethiopia

Water ◽

10.3390/w11112218 ◽

2019 ◽

Vol 11 (11) ◽

pp. 2218 ◽

Cited By ~ 4

Author(s):

Dawit Teweldebirhan Tsige ◽

Venkatesh Uddameri ◽

Farhang. Forghanparast ◽

Elma Annette. Hernandez ◽

Stephen. Ekwaro-Osire

Keyword(s):

Soil Moisture ◽

Meteorological Drought ◽

Evaluation Framework ◽

Agricultural Drought ◽

Hydrologic Processes ◽

Preparedness Planning ◽

Drought Indicators ◽

Drought Preparedness ◽

The Relationship ◽

Meteorological Droughts

Meteorological drought indicators are commonly used for agricultural drought contingency planning in Ethiopia. Agricultural droughts arise due to soil moisture deficits. While these deficits may be caused by meteorological droughts, the timing and duration of agricultural droughts need not coincide with the onset of meteorological droughts due to soil moisture buffering. Similarly, agricultural droughts can persist, even after the cessation of meteorological droughts, due to delayed hydrologic processes. Understanding the relationship between meteorological and agricultural droughts is therefore crucial. An evaluation framework was developed to compare meteorological- and agriculture-related drought indicators using a suite of exploratory and confirmatory tools. Receiver operator characteristics (ROC) was used to understand the covariation of meteorological and agricultural droughts. Comparisons were carried out between SPI-2, SPEI-2, and Palmer Z-index to assess intraseasonal droughts, and between SPI-6, SPEI-6, and PDSI for full-season evaluations. SPI was seen to correlate well with selected agriculture-related drought indicators, but did not explain all the variability noted in them. The correlation between meteorological and agricultural droughts exhibited spatial variability which varied across indicators. SPI is better suited to predict non-agricultural drought states than agricultural drought states. Differences between agricultural and meteorological droughts must be accounted for in order to devise better drought-preparedness planning.

Download Full-text