השוואת שיטות

	עומק אופטי של אירוסולים	מודל מחזור כללי	מדד המשקעים הסטנדרטי
תחום	גאופיזיקה	גאופיזיקה	גאופיזיקה
משפחה	Process / pipeline	Process / pipeline	Process / pipeline
שנת המקור	1929	1975	1993
הוגה השיטה	Anders Ångström	Syukuro Manabe and Richard Wetherald	Thomas McKee, Neil Doesken, and John Kleist
סוג	Optical parameter for aerosol loading quantification	Deterministic coupled atmosphere-ocean simulation	Probabilistic drought indicator
מקור מכונן	Ångström, A. (1929). On the atmospheric transmission of sun radiation and on dust in the air. Geografiska Annaler, 11(2), 156-166.	Manabe, S., & Wetherald, R. T. (1975). The effects of doubling the CO2 concentration on the climate of a general circulation model. Journal of the Atmospheric Sciences, 32(1), 3-15.	McKee, T. B., Doesken, N. J., & Kleist, J. (1993). The relationship of drought frequency and duration to time scales. Proceedings of the Eighth Conference on Applied Climatology, 179-184.
כינויים	AOD, Aerosol Optical Thickness	GCM, Global Climate Model	SPI
קשורות	3	3	3
תקציר	Aerosol Optical Depth (AOD) is a dimensionless measure of aerosol light extinction in the atmosphere, quantifying how much sunlight is scattered and absorbed by particles suspended in air. Formalized by Ångström in 1929 and now routinely measured via satellite (MODIS, Sentinel-5P) and ground networks (AERONET), AOD is essential for air quality monitoring, climate forcing assessment, and visibility prediction.	A General Circulation Model (GCM), also called a Global Climate Model, is a three-dimensional numerical representation of the Earth's atmosphere, oceans, ice, and land surface that simulates physical processes governing weather and climate. Pioneered by Manabe and Wetherald in 1975, GCMs are the primary tools for understanding past climate, projecting future climate change, and investigating climate sensitivity to greenhouse gases and other forcings.	The Standardized Precipitation Index (SPI) is a climate index that quantifies precipitation anomalies relative to historical norms, standardized to account for differences in precipitation climatology across regions. Introduced by McKee, Doesken, and Kleist in 1993, SPI has become a primary tool for drought detection and characterization, adopted by meteorological agencies worldwide for operational drought monitoring and early warning systems.