scholarly journals Developing Objective Operational Definitions for Monitoring Drought

2009 ◽  
Vol 48 (6) ◽  
pp. 1217-1229 ◽  
Author(s):  
Steven M. Quiring
Keyword(s):  
Water Conservation ◽  
Standardized Precipitation Index ◽  
Meteorological Drought ◽  
Severity Index ◽  
Decision Makers ◽  
Drought Severity ◽  
Specific Method ◽  
The Standardized Precipitation Index ◽  
Spatially Variant ◽  
Objective Methodology

Abstract Drought is a complex phenomenon that is difficult to accurately describe because its definition is both spatially variant and context dependent. Decision makers in local, state, and federal agencies commonly use operational drought definitions that are based on specific drought index thresholds to trigger water conservation measures and determine levels of drought assistance. Unfortunately, many state drought plans utilize operational drought definitions that are derived subjectively and therefore may not be appropriate for triggering drought responses. This paper presents an objective methodology for establishing operational drought definitions. The advantages of this methodology are demonstrated by calculating meteorological drought thresholds for the Palmer drought severity index, the standardized precipitation index, and percent of normal precipitation using both station and climate division data from Texas. Results indicate that using subjectively derived operational drought definitions may lead to over- or underestimating true drought severity. Therefore, it is more appropriate to use an objective location-specific method for defining operational drought thresholds.

scholarly journals Commonly Used Drought Indices as Indicators of Soil Moisture in China

2015 ◽  
Vol 16 (3) ◽  
pp. 1397-1408 ◽  
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.

scholarly journals Evaluating Uncertainties in the Projection of Future Drought

2008 ◽  
Vol 9 (2) ◽  
pp. 292-299 ◽  
Author(s):  
Eleanor J. Burke ◽  
Simon J. Brown
Keyword(s):  
Land Surface ◽  
Climate Model ◽  
Climate Modeling ◽  
Standardized Precipitation Index ◽  
Severity Index ◽  
Ensemble Member ◽  
Drought Indices ◽  
Drought Severity ◽  
Hadley Centre ◽  
The Standardized Precipitation Index

Abstract The uncertainty in the projection of future drought occurrence was explored for four different drought indices using two model ensembles. The first ensemble expresses uncertainty in the parameter space of the third Hadley Centre climate model, and the second is a multimodel ensemble that additionally expresses structural uncertainty in the climate modeling process. The standardized precipitation index (SPI), the precipitation and potential evaporation anomaly (PPEA), the Palmer drought severity index (PDSI), and the soil moisture anomaly (SMA) were derived for both a single CO2 (1×CO2) and a double CO2 (2×CO2) climate. The change in moderate drought, defined by the 20th percentile of the relevant 1×CO2 distribution, was calculated. SPI, based solely on precipitation, shows little change in the proportion of the land surface in drought. All the other indices, which include a measure of the atmospheric demand for moisture, show a significant increase with an additional 5%–45% of the land surface in drought. There are large uncertainties in regional changes in drought. Regions where the precipitation decreases show a reproducible increase in drought across ensemble members and indices. In other regions the sign and magnitude of the change in drought is dependent on index definition and ensemble member, suggesting that the selection of appropriate drought indices is important for impact studies.

scholarly journals Performance of Drought Indices in Trichy Region, Tamil Nadu

2019 ◽  
pp. 1-10
Author(s):  
L. Sathya ◽  
R. Lalitha
Keyword(s):  
Tamil Nadu ◽  
Standardized Precipitation Index ◽  
Synthetic Data ◽  
Meteorological Drought ◽  
Severity Index ◽  
Rainfall Anomaly ◽  
Drought Indices ◽  
Drought Severity ◽  
Data Series

Droughts are regional phenomena, which are considered as one of the major natural environmental hazards and severely affect the water resources. Climate variability may result in harmful drought periods in semiarid regions. Meteorological drought indices are considered as important tools for drought monitoring, they are embedded with different theoretical and experimental structures. This study compares the performance of three indices of Standardized Precipitation Index (SPI), Rainfall Anomaly Index (RAI) End Palmer Drought Severity Index (PNPI) to predict long-term drought events using the Thomas-Feiring Model and historical data. For studies of areal drought extent, the 61 years (1951-2011) historical rainfall data of Trichy District were utilized to generate 58 years (2012-2070) synthetic data series so that the characteristics of long-term drought might be determined and the performance of those three indices might be analyzed and compared. The results show that SPI and PNPI perform similarly with regard to drought identification and detailed analysis to determine the characteristics of long-term drought. Finally, the RAI indicated significant deviations from normalized natural processes.

scholarly journals A Hybrid Precipitation Index Inspired by the SPI, PDSI, and MCDI. Part I: Development of the Index

2020 ◽  
Vol 21 (9) ◽  
pp. 1945-1976 ◽  
Author(s):  
Dudley B. Chelton ◽  
Craig M. Risien
Keyword(s):  
Time Scale ◽  
Standardized Precipitation Index ◽  
Severity Index ◽  
Precipitation Index ◽  
Drought Severity ◽  
Fading Memory ◽  
Hybrid Index ◽  
Weighted Averages ◽  
The Standardized Precipitation Index ◽  
Exponentially Weighted

AbstractThe filtering properties of the standardized precipitation index (SPI), the Palmer drought severity index (PDSI), and the model calibrated drought index (MCDI) are investigated to determine their relations to past, present, and future precipitation anomalies in regions with a wide diversity of precipitation characteristics. All three indices can be closely approximated by weighted averages of precipitation, but with different weighting. The SPI is well represented by one-sided, uniformly weighted averages; the MCDI is well represented by one-sided, exponentially weighted averages; and the PDSI is well represented by two-sided, exponentially weighted averages with much higher weighting of past and present precipitation than future precipitation. Detailed analyses identify interpretational complications and other undesirable features in the SPI and PDSI. In addition, the PDSI and MCDI are each restricted to single regionally specific “intrinsic” time scales that can significantly differ between the two indices. Inspired by the strengths of the SPI, PDSI, and MCDI, a hybrid index is developed that consists of exponentially weighted averages of past and present precipitation that are implicit in the PDSI and MCDI. The explicit specification of the exponential weighting allows users to control the time scale of the hybrid index to investigate precipitation variability on any time scale of interest. This advantage over the PDSI and MCDI is analogous to the controllability of the time scale of the SPI, but the exponentially fading memory is more physical than the uniform weighting of past and present precipitation in the SPI.

scholarly journals SPEI-Based Approach to Agricultural Drought Monitoring in Vojvodina Region

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1481 ◽  
Author(s):  
Jovana Bezdan ◽  
Atila Bezdan ◽  
Boško Blagojević ◽  
Minučer Mesaroš ◽  
Borivoj Pejić ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Crop Yields ◽  
Standardized Precipitation Index ◽  
Severity Index ◽  
Climatic Conditions ◽  
Agricultural Drought ◽  
Drought Monitoring ◽  
Drought Severity ◽  
Second Phase ◽  
The Standardized Precipitation Index

This paper presents the standardized precipitation evapotranspiration index (SPEI)-based approach to agricultural drought monitoring (ADM-SPEI approach) combining well-known methods, expert’ critical opinions, and local agro-climatic specificities. The proposed approach has been described in detail in three phases. This allows its application in any region and modification according to different agro-climatic conditions. The application of the ADM-SPEI approach has resulted in obtaining a modified SPEI for different crops (agricultural drought SPEI (AD-SPEIcrop)) in the Vojvodina region. In the first phase of the proposed approach, analytical hierarchy process (AHP) was used to obtain an experts’ group decision regarding the most suitable method for calculating evapotranspiration for a particular analyzed region. In the second phase, SPEI was modified and adjusted to the conditions in Vojvodina, where ET0 was replaced by ETc. In the validation phase, the results of the application of AD-SPEIcrop were compared to crop yields and well-known indices and evaluated by the experts’ feedback. The statistically significant correlations were achieved between AD-SPEIcrop and crop yields. The highest correlations were achieved in the months when the analyzed crops were in the developmental stages when they are most sensitive to drought. The AD-SPEIcrop better correlates to the crop yields compared to SPEI. The comparison of AD-SPEIcrop to the standardized precipitation index (SPI), SPEI, and self-calibrated Palmer drought severity index (SC-PDSI) shows that it can successfully detect dry and wet periods. The results have indicated that the proposed approach can be successfully applied, and AD-SPEIcrop has shown a good performance for agricultural drought monitoring.

A Multiscalar Drought Index Sensitive to Global Warming: The Standardized Precipitation Evapotranspiration Index

2010 ◽  
Vol 23 (7) ◽  
pp. 1696-1718 ◽  
Author(s):  
Sergio M. Vicente-Serrano ◽  
Santiago Beguería ◽  
Juan I. López-Moreno
Keyword(s):  
Global Warming ◽  
Water Balance ◽  
Drought Index ◽  
Standardized Precipitation Index ◽  
Severity Index ◽  
Drought Severity ◽  
Standardized Precipitation Evapotranspiration Index ◽  
Drought Assessment ◽  
The Standardized Precipitation Index

Abstract The authors propose a new climatic drought index: the standardized precipitation evapotranspiration index (SPEI). The SPEI is based on precipitation and temperature data, and it has the advantage of combining multiscalar character with the capacity to include the effects of temperature variability on drought assessment. The procedure to calculate the index is detailed and involves a climatic water balance, the accumulation of deficit/surplus at different time scales, and adjustment to a log-logistic probability distribution. Mathematically, the SPEI is similar to the standardized precipitation index (SPI), but it includes the role of temperature. Because the SPEI is based on a water balance, it can be compared to the self-calibrated Palmer drought severity index (sc-PDSI). Time series of the three indices were compared for a set of observatories with different climate characteristics, located in different parts of the world. Under global warming conditions, only the sc-PDSI and SPEI identified an increase in drought severity associated with higher water demand as a result of evapotranspiration. Relative to the sc-PDSI, the SPEI has the advantage of being multiscalar, which is crucial for drought analysis and monitoring.

EFFECTS OF CHANGES IN CLIMATIC CONDITIONS ON NEW MEXICO PECAN PRODUCTION, PRICE, AND CASH RECEIPTS

2019 ◽  
Vol 10 (02) ◽  
pp. 1950006
Author(s):  
JEE W. HWANG ◽  
OKMYUNG BIN
Keyword(s):  
New Mexico ◽  
Palmer Drought Severity Index ◽  
Standardized Precipitation Index ◽  
Severity Index ◽  
Climatic Conditions ◽  
Drought Indices ◽  
Drought Severity ◽  
High Moisture ◽  
The Standardized Precipitation Index ◽  
Drought Severity Index

This study estimates the effects of changes in climatic conditions on local pecan production, price, and cash receipts in New Mexico, USA, for the period from 1964 to 2014. Our primary measures for estimating the effects are drought indices: the Palmer Drought Severity Index, and the Standardized Precipitation Index. Our results indicate that precipitation is important to pecan yields. Consistent with previous studies, we find the effects of moisture deficits to be more pronounced compared to conditions of high moisture levels. The gains from moderate to extreme wet conditions on cash receipts are estimated to be as high as [Formula: see text]% while the losses from moderate to severe droughts are as high as [Formula: see text]%. Applying these estimates to cash receipts during the years when an actual wet spell and a drought that took place in New Mexico, the values of these effects are [Formula: see text]$12.6 million and [Formula: see text]$59.7 million, respectively.

scholarly journals Characterization of Bias during Meteorological Drought Calculation in Time Series Out-of-Sample Validation

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2531
Author(s):  
Konstantinos Mammas ◽  
Demetris F. Lekkas
Keyword(s):  
Probability Distributions ◽  
Standardized Precipitation Index ◽  
Information Leakage ◽  
Meteorological Drought ◽  
Climatic Conditions ◽  
Training Data ◽  
Drought Severity ◽  
Training Set ◽  
The Standardized Precipitation Index

The standardized precipitation index (SPI) is used for characterizing and predicting meteorological droughts on a range of time scales. However, in forecasting applications, when SPI is computed on the entire available dataset, prior to model-validation, significant biases are introduced, especially under changing climatic conditions. In this paper, we investigate the theoretical and numerical implications that arise when SPI is computed under stationary and non-stationary probability distributions. We demonstrate that both the stationary SPI and non-stationary SPI (NSPI) lead to increased information leakage to the training set with increased scales, which significantly affects the characterization of drought severity. The analysis is performed across about 36,500 basins in Sweden, and indicates that the stationary SPI is unable to capture the increased rainfall trend during the last decades and leads to systematic underestimation of wet events in the training set, affecting up to 22% of the drought events. NSPI captures the non-stationary characteristics of accumulated rainfall; however, it introduces biases to the training data affecting 19% of the drought events. The variability of NSPI bias has also been observed along the country’s climatic gradient with regions in snow climates strongly being affected. The findings propose that drought assessments under changing climatic conditions can be significantly influenced by the potential misuse of both SPI and NSPI, inducing bias in the characterization of drought events in the training data.

scholarly journals Changes in drought features at the European level over the last 120 years

2021 ◽  
Vol 21 (5) ◽  
pp. 1685-1701
Author(s):  
Monica Ionita ◽  
Viorica Nagavciuc
Keyword(s):  
Air Temperature ◽  
Potential Evapotranspiration ◽  
Standardized Precipitation Index ◽  
Severity Index ◽  
Drought Indices ◽  
Drought Severity ◽  
European Level ◽  
Essential Components ◽  
Compound Events ◽  
The Standardized Precipitation Index

Abstract. In this study we analyze drought features at the European level over the period 1901–2019 using three drought indices: the standardized precipitation index (SPI), the standardized precipitation evapotranspiration index (SPEI), and the self-calibrated Palmer drought severity index (scPDSI). The results based on the SPEI and scPDSI point to the fact that Central Europe (CEU) and the Mediterranean region (MED) are becoming dryer due to an increase in the potential evapotranspiration and mean air temperature, while North Europe (NEU) is becoming wetter. By contrast, the SPI drought does not reveal these changes in the drought variability, mainly due to the fact that the precipitation does not exhibit a significant change, especially over CEU. The SPEI12 indicates a significant increase both in the drought frequency and area over the last three decades for MED and CEU, while SPI12 does not capture these features. Thus, the performance of the SPI may be insufficient for drought analysis studies over regions where there is a strong warming signal. By analyzing the frequency of compound events (e.g., high temperatures and droughts), we show that the potential evapotranspiration and the mean air temperature are becoming essential components for drought occurrence over CEU and MED. This, together with the projected increase in the potential evapotranspiration under a warming climate, has significant implications concerning the future occurrence of drought events, especially for the MED and CEU regions.

scholarly journals Spatiotemporal Variations of Drought in the Arid Region of Northwestern China during 1950–2012

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Wenjun Huang ◽  
Jianjun Yang ◽  
Yang Liu ◽  
Entao Yu
Keyword(s):  
Arid Region ◽  
Standardized Precipitation Index ◽  
Severity Index ◽  
Northwestern China ◽  
Drought Severity ◽  
Spatiotemporal Variations ◽  
Drought Frequency ◽  
The Qilian Mountains ◽  
The 1960S ◽  
The Standardized Precipitation Index

There are water resource shortages and frequent drought disasters in the arid region of northwestern China (ARNC). The purpose of this study is to understand the spatiotemporal variations of the droughts in this region and to further estimate future changes. Multiple drought indexes such as the standardized precipitation index (SPI), the standardized precipitation evapotranspiration index (SPEI), and the self-calibrated Palmer drought severity index (SC-PDSI) are used to investigate the temporal and spatial characteristics of the ARNC drought from 1950 to 2012. Our results indicate the following: (1) The drought indexes exhibit significant increasing trends, and the highest drought frequency occurred in the 1960s, followed by a decreasing trend during the next few decades. All four seasons exhibit a wet trend, with a higher drought frequency in summer than in the other seasons. (2) The changes of the drought indexes in the ARNC also exhibit distinct spatial variations, with a wet trend in the subregions of North Xinjiang (NXJ), the Tianshan Mountains (TS), South Xinjiang (SXJ), and the Qilian Mountains (QL), but with a dry trend in the subregions of the Hexi Corridor (HX) and the western part of Inner Mongolia (WIM). (3) There was a major climate variability in the ARNC that occurred in the 1980s, and there were dry and wet climate oscillation periods of 8a, 17a, and >20a.

Sign in / Sign up

Export Citation Format

Share Document