Abstract
The structure of the Palmer Drought Severity Index (PDSI), which is perhaps the most widely used regional index of drought, is examined. The PDSI addresses two of the most elusive properties of droughts: their intensity and their beginning and ending times. Unfortunately, the index uses rather arbitrary rules in quantifying these properties. In addition, the methodology used to standardize the values of the PDSI for different locations and months is based on very limited comparisons and is only weakly justified on physical or statistical grounds. Under certain conditions, the PDSI values are very sensitive to the criteria for ending an “established” drought and precipitation during a month can have a very large effect on the PDSI values for several previous months. The distribution of the PDSI conditioned on the value for the previous month may often be bimodal. Thus, conventional time series models may be quite limited in their ability to capture the stochastic properties of the index.
Keywords
Index (typography)ClimatologyPrecipitationMathematicsEconometricsStatisticsMeteorologyGeographyComputer scienceGeology
Affiliated Institutions
Related Publications
APACHE II
This paper presents the form and validation results of APACHE II, a severity of disease classification system. APACHE II uses a point score based upon initial values of 12 routi...
Using Supermatrices for Phylogenetic Inquiry: An Example Using the Sedges
In this article, we use supermatrix data-mining methods to reconstruct a large, highly inclusive phylogeny of Cyperaceae from nucleotide data available on GenBank. We explore th...
Goodness-of-fit indices for partial least squares path modeling
This paper discusses a recent development in partial least squares (PLS) path modeling, namely goodness-of-fit indices. In order to illustrate the behavior of the goodness-of-fi...
High-Resolution Image Synthesis with Latent Diffusion Models
By decomposing the image formation process into a sequential application of denoising autoencoders, diffusion models (DMs) achieve state-of-the-art synthesis results on image da...
A survey on Image Data Augmentation for Deep Learning
Abstract Deep convolutional neural networks have performed remarkably well on many Computer Vision tasks. However, these networks are heavily reliant on big data to avoid overfi...
Publication Info
- Year
- 1984
- Type
- article
- Volume
- 23
- Issue
- 7
- Pages
- 1100-1109
- Citations
- 1353
- Access
- Closed
External Links
Social Impact
Altmetric
PlumX Metrics
Social media, news, blog, policy document mentions
Citation Metrics
1353
OpenAlex
Cite This
William M. Alley
(1984).
The Palmer Drought Severity Index: Limitations and Assumptions.
Journal of Climate and Applied Meteorology
, 23
(7)
, 1100-1109.
https://doi.org/10.1175/1520-0450(1984)023<1100:tpdsil>2.0.co;2
Identifiers
- DOI
- 10.1175/1520-0450(1984)023<1100:tpdsil>2.0.co;2