GIS-based composite indices for drought assessment: a scientometric analysis

Drought has become an increasingly recurrent phenomenon worldwide with far-reaching societal and environmental consequences. To adequately manage the drought, the scientific research is essential. In recent decades numerous indices were developed for drought analysis. The evolution of the geospatial technologies has enabled the design of several indices, based both on terrestrial and satellite data, to analyze the drought characteristics. The most common indices are based on hydroclimatic parameters, simple or combined. In recent years, complex indices (called composite, integrated, multivariate or hybrid) were developed, which incorporate several drought control variables, combined and mapped in GIS environment. They allow a more reliable analysis of drought and the identification of areas susceptible to this hazard. The aim of this paper is to provide an overview of publications on the composite indices for drought assessment developed in GIS environment, based on a scientometric analysis.

The study relies on the Web of Science (WoS) and Scopus databases, from which a total of 345 papers were initially extracted (205 from WoS and 140 from Scopus) by searching for the expressions integrated drought index gis; composite drought gis; multivariate drought gis. Duplicates were removed using the ScientoPy software. Finally, 262 papers were retained from both databases, published between 1994 and 2024. The same software was used for statistical analysis regarding some characteristics of the publications (e.g., the countries and institutions of affiliation of the authors, the scientific fields of the papers, connections between authors, etc.) Furthermore, some of this data was mapped using the ArcGisPro software. For the analysis of author clusters, the VOSviewer software was used.

The results showed that most authors of the identified papers are affiliated in Asian countries, especially in India (64) and China (58), followed by the United States (42). Most authors' affiliation institutions are located in China: the Chinese Academy of Sciences has the highest frequency (10), followed by the Peking University (5), and the University of Chinese Academy of Sciences (5). Iran is also noteworthy with University of Tehran (7), as well as India, represented by the Vidyasagar University (6).

The number of publications per year varied during the analyzed period, with the highest number of 39 in 2024. The major scientific fields to which the papers on composite drought indices belong were: Environmental Sciences and Ecology (76), Water Resources (60), Geology (50), Remote Sensing (34), and Meteorology and Atmospheric Sciences (28).

Out of a total of 1086 authors of the analyzed publications, the highest number of common connections was 35, in general, between Asian researchers. Furthermore, many of the 35 authors with the most connections collaborated between 2006 and 2016, while the other groups published after 2020.

Overall, this scientometric analysis shows that the use in drought research of composite indices developed in GIS environment is still quite limited although in the last 5 years an increase in the number of papers on this topic was noted (mainly in Asian countries). Therefore, more attention should be paid to this more reliable method of drought analysis.