Tracers of Rapid Transport in the Lower Stratosphere
This thesis consists of three parts, each related to the use of tracer measurements to diagnose the small-scale structure and mechanisms by which air is transported, both vertically and horizontally, in the lower stratosphere. 1. I demonstrate that the isotopic composition of water vapor can diagnos...
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| Format: | Thesis |
| Language: | English |
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2001
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| Online Access: | https://thesis.library.caltech.edu/7474/ https://thesis.library.caltech.edu/7474/1/Moyer%202001.pdf https://resolver.caltech.edu/CaltechTHESIS:02122013-103240444 |
| Summary: | This thesis consists of three parts, each related to the use of tracer measurements to diagnose the small-scale structure and mechanisms by which air is transported, both vertically and horizontally, in the lower stratosphere. 1. I demonstrate that the isotopic composition of water vapor can diagnose rapid convective transport across the tropopause. I use data from the space shuttle- and balloon-borne Fourier transform solar occultation spectrometers ATMOS (Atmospheric Trace MOlecule Spectrometer) and Mark-IV to reconstruct the mean deuterium isotopic composition of water entering the stratosphere. Initial δD is -670 per mil (33% of deuterated water retained). I construct a one-dimensional model simulating isotopic fractionation during ascent to the tropopause and demonstrate that for all but the most rapid ascent. virtually all deuterated water is stripped from an air parcel in the last few kilometers of the uppermost troposphere. The observed stratospheric δD is then far heavier than modeled depletions under most conditions. I conclude that the observations can be matched only by substantial evaporation of lofted condensate or by ascent in highly-supersaturated conditions, and infer that mean stratospheric air must have experienced rapid convection to at least near-tropopause altitudes. This study serves to demonstrate that the isotopic composition of water vapor is a valuable tracer that can be used to constrain mechanisms of stratosphere-troposphere transport. 2. I use in-situ tunable diode laser measurements of CO, H_2O, and N_2O taken over Fairbanks, AK to show rapid transport by streamers of air in the lower stratosphere. I was part of a team that used ALIAS and JPL-H2O, two tunable diode laser spectrometers built by the Webster group of the Jet Propulsion Laboratory, to obtain data in the upper troposphere and lower stratosphere on 21 ER-2 flights between April and September, 1991, during the POLARIS (Photochemistry of Ozone Loss in the Arctic Region In Summer) mission. I use this dataset to identify ... |
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