Modeling Water Vapor in the Upper Troposphere and Lower Stratosphere

Gulstad, Line; Isaksen, I. S. A.

doi:10.3319/tao.2007.18.3.415(ea)

Cited by 3 publications

(2 citation statements)

References 28 publications

(38 reference statements)

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“…Distinguishing the importance of the relevant mechanisms will allow models to better simulate how water vapor pathways linking the troposphere and stratosphere will change with increased climate forcing by carbon dioxide and methane. Many modeling studies that attempt to reproduce the observed water vapor mixing ratio of the TTL have suggested that convective ice lofting and evaporation may be unimportant to the region's water budget, and that mixing ratios of water vapor in air crossing the tropical tropopause can be well explained simply by the minimum temperature experienced by those air parcels [ Fueglistaler et al , 2004, 2005; Gulstad and Isaksen , 2007; Cau et al , 2007]. However, attempts to simultaneously model HDO mixing ratios find that convection is necessary to accurately reproduce observed profiles of both H 2 O and HDO [ Dessler et al , 2007; Bony et al , 2008].…”

Section: Introductionmentioning

confidence: 99%

Influence of convection on the water isotopic composition of the tropical tropopause layer and tropical stratosphere

Sayres¹,

Pfister²,

Hanisco³

et al. 2010

J. Geophys. Res.

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[1] We present the first in situ measurements of HDO across the tropical tropopause, obtained by the integrated cavity output spectroscopy (ICOS) and Hoxotope water isotope instruments during the Costa Rica Aura Validation Experiment (CR-AVE) and Tropical Composition, Cloud and Climate Coupling (TC4) aircraft campaigns out of Costa Rica in winter and summer, respectively. We use these data to explore the role convection plays in delivering water to the tropical tropopause layer (TTL) and stratosphere. We find that isotopic ratios within the TTL are inconsistent with gradual ascent and dehydration by in-situ cirrus formation and suggest that convective ice lofting and evaporation play a strong role throughout the TTL. We use a convective influence model and a simple parameterized model of dehydration along back trajectories to demonstrate that the convective injection of isotopically heavy water can account for the predominant isotopic profile in the TTL. Air parcels with significantly enhanced water vapor and isotopic composition can be linked via trajectory analysis to specific convective events in the Western Tropical Pacific, Southern Pacific Ocean, and South America. Using a simple model of dehydration and hydration along trajectories we show that convection during the summertime TC4 campaign moistened the upper part of the TTL by as much as 2.0 ppmv water vapor. The results suggest that deep convection is significant for the moisture budget of the tropical near-tropopause region and must be included to fully model the dynamics and chemistry of the TTL and lower stratosphere.

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Section: Introductionmentioning

confidence: 99%

Influence of convection on the water isotopic composition of the tropical tropopause layer and tropical stratosphere

Sayres¹,

Pfister²,

Hanisco³

et al. 2010

J. Geophys. Res.

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“…direct injection of overshooting convection (e.g., Danielson 1982; Dessler 2000, 2001) and the advection of slow ascending air crossing the cold tropical tropopause, (Holton and Gettelman 2001;Fueglistaler et al 2005). Recent studies have brought attention to water vapor in the UTLS region (Mote et al 1996;Gettelman et al 2002;Gulstad et al 2007). Considerable effort has been made to understand in detail, how the air entering the stratosphere gets dehydrated.…”

Section: Introductionmentioning

confidence: 99%

Aura-MLS Observations of Water Vapor Entering the Stratosphere over the Northern Bay of Bengal and East Equatorial Indian Ocean

Uma¹,

Das²,

Das³

et al. 2013

Terr. Atmos. Ocean. Sci.

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The space-time variations in water vapor in the upper troposphere and lower stratosphere (UTLS) over the Asian summer monsoon (ASM) regions are investigated using six years of observations from the Aura-MLS to understand the ASM role in transporting water vapor to the tropical stratosphere. While some previous studies indicated that the ASM plays a role in dehydrating the lower stratosphere, the present investigations revealed that the ASM region plays an active role in hydrating rather than dehydrating the tropical lower stratosphere. The analysis also shows that only during the month of August (ASM) is moist air pumped into the lower stratosphere over the two key geographical locations (India and Western Pacific). The air parcel from the tropical tropopause takes approximately 10 -12 months to reach the mid-stratosphere with an ascent rate of 2.8 × 10 -4 m s -1 . Thus it is envisaged that the present results will have important implications in understanding the exchange processes across the tropopause and its role in stratosphere chemistry.

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Spatial distribution, temporal variation, and transport characteristics of atmospheric water vapor over Central Asia and the arid region of China

Guan

Yang

Zhang

et al. 2019

Global and Planetary Change

100

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Modeling Water Vapor in the Upper Troposphere and Lower Stratosphere

Cited by 3 publications

References 28 publications

Influence of convection on the water isotopic composition of the tropical tropopause layer and tropical stratosphere

Influence of convection on the water isotopic composition of the tropical tropopause layer and tropical stratosphere

Aura-MLS Observations of Water Vapor Entering the Stratosphere over the Northern Bay of Bengal and East Equatorial Indian Ocean

Spatial distribution, temporal variation, and transport characteristics of atmospheric water vapor over Central Asia and the arid region of China

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