scholarly journals Comparing Palmer Drought Severity Index drought assessments using the traditional offline approach with direct climate model outputs

2020 ◽  
Vol 24 (6) ◽  
pp. 2921-2930 ◽  
Author(s):  
Yuting Yang ◽  
Shulei Zhang ◽  
Michael L. Roderick ◽  
Tim R. McVicar ◽  
Dawen Yang ◽  
...  
Keyword(s):  
Climate Model ◽  
Palmer Drought Severity Index ◽  
Severity Index ◽  
Cmip5 Models ◽  
Drought Indices ◽  
Drought Severity ◽  
Systematic Change ◽  
Climate Projections ◽  
Elevated Atmospheric Co2 ◽  
Drought Severity Index

Abstract. Anthropogenic warming has been projected to increase global drought for the 21st century when calculated using traditional offline drought indices. However, this contradicts observations of the overall global greening and little systematic change in runoff over the past few decades and climate projections of future greening with slight increases in global runoff for the coming century. This calls into question the drought projections based on traditional offline drought indices. Here we calculate a widely used traditional drought index (i.e., the Palmer Drought Severity Index, PDSI) using direct outputs from 16 Coupled Model Intercomparison Project Phase 5 (CMIP5) models (PDSI_CMIP5) such that the hydrologic consistency between PDSI_CMIP5 and CMIP5 models is maintained. We find that the PDSI_CMIP5-depicted drought increases (in terms of drought severity, frequency, and extent) are much smaller than that reported when PDSI is calculated using the traditional offline approach that has been widely used in previous drought assessments under climate change. Further analyses indicate that the overestimation of PDSI drought increases reported previously using the PDSI is primarily due to ignoring the vegetation response to elevated atmospheric CO2 concentration ([CO2]) in the traditional offline calculations. Finally, we show that the overestimation of drought using the traditional PDSI approach can be minimized by accounting for the effect of CO2 on evapotranspiration.

scholarly journals Little change in Palmer Drought Severity Index across global land under warming in climate projections

2020 ◽  
Author(s):  
Yuting Yang ◽  
Shulei Zhang ◽  
Michael L. Roderick ◽  
Tim R. McVicar ◽  
Dawen Yang ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Palmer Drought Severity Index ◽  
Severity Index ◽  
Agricultural Drought ◽  
Cmip5 Models ◽  
Drought Indices ◽  
Drought Severity ◽  
Systematic Change ◽  
Climate Projections ◽  
Drought Severity Index

Abstract. Anthropogenic warming is reported to increase global drought for the 21st century when calculated using offline drought indices. However, this contradicts observations of greening and little systematic change in runoff over the past few decades and climate projections of future greening with slight increases in global runoff for the coming century. This calls into question the drought projections based on offline drought indices. To resolve this paradox, here we calculate a widely-used conventional drought index (i.e., the Palmer Drought Severity Index, PDSI) using direct outputs from 16 CMIP5 models (PDSI_CMIP5) such that the hydrologic consistency between PDSI_CMIP5 and CMIP5 models is maintained. Results show that the global PDSI_CMIP5 remains generally unchanged as climate warms, demonstrating that CMIP5 models do not actually project a general increase in PDSI drought (more reflecting soil moisture/agricultural drought) under future warming. Further analyses indicate that the projected increase in PDSI drought reported previously is primarily due to ignoring the vegetation response to elevated atmospheric CO2 concentration ([CO2]) in the offline calculations. On one hand, elevated [CO2] directly reduces stomatal opening; on the other hand, elevated [CO2] increases air temperature and thus vapor pressure deficit, which also causes partial stomatal closure. Finally, we show that the overestimation of PDSI drought can be avoided by directly using the relevant climate model outputs or by accounting for the effect of CO2 on evapotranspiration. Our findings refute the common warming leads to drying perception and highlight the importance of elevated CO2 in controlling future terrestrial hydrologic changes through vegetation responses.

scholarly journals The impact of climate mitigation on projections of future drought

2013 ◽  
Vol 17 (6) ◽  
pp. 2339-2358 ◽  
Author(s):  
I. H. Taylor ◽  
E. Burke ◽  
L. McColl ◽  
P. D. Falloon ◽  
G. R. Harris ◽  
...  
Keyword(s):  
Climate Model ◽  
Severity Index ◽  
Baseline Period ◽  
Drought Indices ◽  
Drought Severity ◽  
Climate Mitigation ◽  
Climate Projections ◽  
Standardised Precipitation Index ◽  
The Impact ◽  
Future Emissions

Abstract. Drought is a cumulative event, often difficult to define and involving wide-reaching consequences for agriculture, ecosystems, water availability, and society. Understanding how the occurrence of drought may change in the future and which sources of uncertainty are dominant can inform appropriate decisions to guide drought impacts assessments. Our study considers both climate model uncertainty associated with future climate projections, and future emissions of greenhouse gases (future scenario uncertainty). Four drought indices (the Standardised Precipitation Index (SPI), Soil Moisture Anomaly (SMA), the Palmer Drought Severity Index (PDSI) and the Standardised Runoff Index (SRI)) are calculated for the A1B and RCP2.6 future emissions scenarios using monthly model output from a 57-member perturbed parameter ensemble of climate simulations of the HadCM3C Earth System model, for the baseline period 1961–1990, and the period 2070–2099 ("the 2080s"). We consider where there are statistically significant increases or decreases in the proportion of time spent in drought in the 2080s compared to the baseline. Despite the large range of uncertainty in drought projections for many regions, projections for some regions have a clear signal, with uncertainty associated with the magnitude of change rather than direction. For instance, a significant increase in time spent in drought is generally projected for the Amazon, Central America and South Africa whilst projections for northern India consistently show significant decreases in time spent in drought. Whilst the patterns of changes in future drought were similar between scenarios, climate mitigation, represented by the RCP2.6 scenario, tended to reduce future changes in drought. In general, climate mitigation reduced the area over which there was a significant increase in drought but had little impact on the area over which there was a significant decrease in time spent in drought.

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.

TRANSFORMING THE PALMER DROUGHT SEVERITY INDEX INTO A STANDARDIZED MULTI-SCALAR INDEX: ASSESSING THE NORMALITY ASSUMPTION UNDER SOUTH AMERICA TROPICAL-SUBTROPICAL CONDITIONS

2018 ◽  
Vol 55 (5) ◽  
pp. 752-764
Author(s):  
GABRIEL CONSTANTINO BLAIN ◽  
ANA CAROLINA FREITAS XAVIER
Keyword(s):  
Time Scales ◽  
Palmer Drought Severity Index ◽  
Severity Index ◽  
Likelihood Method ◽  
Drought Indices ◽  
Drought Severity ◽  
Water Capacity ◽  
Available Water ◽  
Available Water Capacity ◽  
Drought Severity Index

SUMMARYTwo of the most common criticisms over the widely used Palmer Drought Severity Index (PDSI) is that it cannot be calculated at different time scales and it is not as spatially comparable as other Standardized Drought Indices (SDI), such as the Standardized Precipitation Index (SPI). Therefore, the hypothesis that the PDSI may be transformed into a multi-scalar index sharing the same normalized nature of others SDI has been proposed in the scientific literature. This hypothesis was extensively evaluated in this study by statistical methods largely used to assess and improve the performance of others standardized drought indices (e.g. SPI). In general terms, these methods evaluated the ability of the transformed/probability-based Palmer's Index to approach the standard normal distribution. The strategy of basing the selection of a distribution for calculating such an index on its performance within the range of typical drought and flood events was adopted. The testing region was the State of São Paulo, a tropical-subtropical region of Brazil. Time scales ranging from 1- to 12-month and Available Water Capacity equal to 50, 100 and 150 mm were also considered. A computational algorithm for calculating the new version of the Palmer's index is also provided. The Generalized Logistic distribution with parameters estimated by the maximum likelihood method is recommended to calculate the new index. The results of the normality tests are consistent with the above-mentioned strategy. From a scientific standpoint, the results support the hypothesis of this study. Therefore, we conclude that the new Standardized Palmer Drought Index (SPDI) is capable of meeting the normally assumption under tropical-subtropical climatic conditions of Brazil. In other words, the new SPDI has shown to be capable of representing floods and drought events in a similar probabilistic/normalized way. This conclusion holds true for time scales ranging from 1- to 12-month and Available Water Capacity equal to 50, 100 and 150 mm.

scholarly journals Analysis of wet and dry season by using the Palmer Drought Severity Index (PDSI) over Java Island

2021 ◽  
Author(s):  
Sinta Berliana S. ◽  
Indah Susanti ◽  
Bambang Siswanto ◽  
Amalia Nurlatifah ◽  
Hidayatul Latifah ◽  
...  
Keyword(s):  
Palmer Drought Severity Index ◽  
Severity Index ◽  
Dry Season ◽  
Drought Severity ◽  
Drought Severity Index

Spatial and temporal characteristics of wildfires in Mississippi, USA

2010 ◽  
Vol 19 (1) ◽  
pp. 14 ◽  
Author(s):  
Katarzyna Grala ◽  
William H. Cooke
Keyword(s):  
Palmer Drought Severity Index ◽  
Severity Index ◽  
The State ◽  
Anthropogenic Factors ◽  
Burned Area ◽  
Drought Severity ◽  
Temporal Characteristics ◽  
Wildfire Occurrence ◽  
Spatial And Temporal Characteristics ◽  
Drought Severity Index

Forests constitute a large percentage of the total land area in Mississippi and are a vital element of the state economy. Although wildfire occurrences have been considerably reduced since the 1920s, there are still ~4000 wildfires each year in Mississippi burning over 24 000 ha (60 000 acres). This study focusses on recent history and various characteristics of Mississippi wildfires to provide better understanding of spatial and temporal characteristics of wildfires in the state. Geographic information systems and Mississippi Forestry Commission wildfire occurrence data were used to examine relationships between climatic and anthropogenic factors, the incidence, burned area, wildfire cause, and socioeconomic factors. The analysis indicated that wildfires are more frequent in southern Mississippi, in counties covered mostly by pine forest, and are most prominent in the winter–spring season. Proximity to roads and cities were two anthropogenic factors that had the most statistically significant correlation with wildfire occurrence and size. In addition, the validity of the Palmer Drought Severity Index as a measure of fire activity was tested for climatic districts in Mississippi. Analysis indicated that drought influences fire numbers and size during summer and fall (autumn). The strongest relationship between the Palmer Drought Severity Index and burned area was found for the southern climatic districts for the summer–fall season.

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