Proportions of Convective and Stratiform Precipitation Revealed in Water Isotope Ratios
| Autor: | Ulrike Romatschke, Pradeep K. Aggarwal, Courtney Schumacher, Luis Araguas-Araguas, Peter Berg, Dagnachew Legesse Belachew, Fred J. Longstaffe, Aaron Funk |
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| Rok vydání: | 2016 |
| Předmět: |
Convection
010504 meteorology & atmospheric sciences Isotope oxygen isotopes tritium 0208 environmental biotechnology Climate change 02 engineering and technology stratiform precipitation Atmospheric sciences 01 natural sciences Isotopes of oxygen 020801 environmental engineering Water Resource Management Hydrology (agriculture) Geochemistry convective precipitation Earth Sciences General Earth and Planetary Sciences Precipitation Water cycle Hydrology Geology 0105 earth and related environmental sciences Convective precipitation |
| Zdroj: | Earth Sciences Publications |
| Popis: | Tropical and midlatitude precipitation is fundamentally of two types, spatially-limited and high-intensity convective or widespread and lower-intensity stratiform, owing to differences in vertical air motions and microphysical processes governing rain formation. These processes are difficult to observe or model and precipitation partitioning into rain types is critical for understanding how the water cycle responds to climate changes. Here, we combine two independent data sets – convective and stratiform precipitation fractions, derived from the Tropical Rainfall Measuring Mission satellite or synoptic cloud observations, and stable isotope and tritium compositions of surface precipitation, derived from a global network – to show that isotope ratios reflect rain type proportions and are negatively correlated with stratiform fractions. Condensation and riming associated with boundary layer moisture produces higher isotope ratios in convective rain, along with higher tritium when riming in deep convection occurs with entrained air at higher altitudes. Based on our data, stable isotope ratios can be used to monitor changes in the character of precipitation in response to periodic variability or changes in climate. Our results also provide observational constraints for an improved simulation of convection in climate models and a better understanding of isotope variations in proxy archives, such as speleothems and tropical ice. |
| Databáze: | OpenAIRE |
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