قارن الطرق

	مطيافية الكتلة لنظائر العناصر	مؤشر التوحيد القياسي للهطول
المجال	الجيوفيزياء	الجيوفيزياء
العائلة	Process / pipeline	Process / pipeline
سنة النشأة	1994	1993
صاحب الطريقة	Thomas Coplen and others	Thomas McKee, Neil Doesken, and John Kleist
النوع	Measurement of stable and radiogenic isotope ratios	Probabilistic drought indicator
المصدر التأسيسي	Coplen, T. B. (1994). Reporting of stable hydrogen, carbon, and oxygen isotopic abundances. Pure and Applied Chemistry, 66(2), 273-276.	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.
الأسماء البديلة	IRMS	SPI
ذات صلة	3	3
الملخص	Isotope Ratio Mass Spectrometry (IRMS) is an analytical technique that measures the relative abundance of stable isotopes (H, C, N, O, S) and some radiogenic isotopes (e.g., ⁸⁷Sr/⁸⁶Sr) in samples with high precision. Standardized by Coplen and colleagues, IRMS enables paleoclimate reconstruction, source tracing (diet, water origin), geochemical fingerprinting, and age dating through radiogenic isotopes.	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.