Spatiotemporal Characteristics of Meteorological Drought During the Past Half Century in Different Climates Over Iran

The present study compares the main characteristics (intensity, duration, and frequency) of meteorological drought events in the four climates (Hyperarid, Arid, Semiarid, and Humid) of Iran. For this purpose, three drought indices, including Standardized Precipitation Index (SPI), Reconnaissance Drought Index (RDI), and Standardized Precipitation Evapotranspiration Index (SPEI), were employed at the timescales of 1-, 3-, 6-, 9- and 12-months. These indices were compared by utilizing long-term data of 41 synoptic meteorological stations for the recent half century, 1969–2019. The long-term analysis of drought indices indicates that the duration and intensity of drought events have temporally risen after the 1998–99 period. Iran has experienced the longest duration (40 months) of extreme drought during Dec 98–Mar 02 and Jan 18–Mar 18, respectively. Spatial patterns demonstrate that drought intensity uniformly increased in SPI1 to SPI12, and SPEI3 to SPEI12, from humid and semiarid to arid and hyperarid regions. The average drought duration in studied stations for SPI, SPEI and RDI indices equaled 9, 12, and 9 months, respectively. In addition, mean drought frequencies are calculated at 14, 17, and 13 percent for SPI, SPEI and RDI indices, respectively. Generally, SPEI compared to SPI and RDI shows greater duration and frequency of drought events, particularly in arid and hyperarid regions. The research shows the crucial role of climatic variables in detecting drought characteristics and the importance of selecting appropriate drought indices in various climates.

Updates on Palliative Medicine in the COVID-19 Era

The advances in knowledge in the field of pain medicine in the last half century have recently been reported from both the scientific and the social points of view [...]

Ecolinguistics: A half-century overview

The last 50 years have witnessed ecolinguistics come into bloom as a mature domain. This paper aims to examine the half-century development of ecolinguistics by reviewing its backgrounds, definitions, strands, and approaches, and also briefly previewing its future horizons. The birth of ecolinguistics can be attributed to such ecological necessities as the ecological crisis as an essential root, and an ecological perspective for linguistics as a linguistic necessity, together with six ecolinguistic turns in this domain (Section 2). Since the emergence of ecolinguistics in the 1970s, various definitions for ecolinguistics as an evolving concept have come into being, involving the geographical, conceptual, disciplinary, methodological, and practical sides (Section 3). Figures who have contributed to the development of this domain can be divided into old strands like Haugenian and Hallidayan ecolinguistics, as well as new strands such as strong ecolinguistics and the latest radical embodied ecolinguistics (Section 4). Given the diverse definitions and strands, a set of approaches have taken shape, ranging from the Haugenian approach to ecological discourse analysis (Section 5). Due to major problems found in reviewing four parts of ecolinguistics, it is high time three shifts in perspective be put into effect in ecolinguistics that can promise its future horizons.

Emerging investigator series: Modeling of Wastewater Treatment Bioprocesses: Current Development and Future Opportunities

For more than a half-century, modelers have developed various modeling strategies to facilitate the transition of wastewater treatment bioprocesses from lab-scale demonstration to full-scale applications. This review presents the mathematical...