Observations of deep convective influence on stratospheric water vapor and its isotopic composition

Hanisco, T. F.; Moyer, E. J.; Weinstock, E. M.; Clair, Jason M. St.; Sayres, D. S.; Smith, J. B.; Lockwood, R.; Anderson, James G.; Dessler, A. E.; Keutsch, Frank N.; Spackman, J. R.; Read, W. G.; Bui, T. P.

doi:10.1029/2006gl027899

Cited by 123 publications

(158 citation statements)

References 27 publications

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“…As mentioned above, the observed abundance of stratospheric HDO (Moyer et al, 1996;Keith et al, 2000;Johnson et al, 2001;Hanisco, et al, 2007, Steinwagner et al, 2010 exceeds the amount predicted by Rayleigh fractionation, a theoretical limit derived by assuming that HDO-rich condensate formation and removal occurs at 100 % RH. One explanation for the larger than expected stratospheric HDO abundance is the direct injection and evaporation of HDOrich ice into the stratosphere through convective lofting.…”

Section: Convective Moisteningmentioning

confidence: 98%

Dehydration of the stratosphere

2011

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Abstract. Domain filling, forward trajectory calculations are used to examine the global dehydration processes that control stratospheric water vapor. As with most Lagrangian models of this type, water vapor is instantaneously removed from the parcel to keep the relative humidity (RH) with respect to ice from exceeding saturation or a specified super-saturation value. We also test a simple parameterization of stratospheric convective moistening through ice lofting and the effect of gravity waves as a mechanism that can augment dehydration. Comparing diabatic and kinematic trajectories driven by the MERRA reanalysis, we find that, unlike the results from Liu et al. (2010), the additional transport due to the vertical velocity "noise" in the kinematic calculation creates too dry a stratosphere and a too diffuse a water-vapor tape recorder signal compared observations. We also show that the kinematically driven parcels are more likely to encounter the coldest tropopause temperatures than the diabatic trajectories. The diabatic simulations produce stratospheric water vapor mixing ratios close to that observed by Aura's Microwave Limb Sounder and are consistent with the MERRA tropical tropopause temperature biases. Convective moistening, which will increase stratospheric HDO, also increases stratospheric water vapor while the addition of parameterized gravity waves does the opposite. We find that while the Tropical West Pacific is the dominant dehydration location, but dehydration over Tropical South America is also important. Antarctica makes a small contribution to the overall stratospheric water vapor budget as well by releasing very dry air into the Southern Hemisphere stratosphere following the break up of the winter vortex.

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Section: Convective Moisteningmentioning

confidence: 98%

Dehydration of the stratosphere

2011

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“…If water vapor in the troposphere is carried upward by slow ascend, it is expected that the HDO/H 2 O ratio should be very small in the UTLS because most of the HDO would have condensed and precipitated out. Yet both satellite data (Moyer et al 1996;Kuang et al 2003) and aircraft observations (Hanisco et al 2007) show that the UTLS HDO/H 2 O ratio is much higher than can be explained by the slow ascend scenario. On the other hand, if the tropospheric water is transported by rapid convection to deep convective storms, then the water vapor can be transported so rapidly by the strong updrafts in these storms that HDO either wouldn't have time to condense, or if it does condense, the resulting condensed water (mostly in ice form) can be injected directly into the UTLS and eventually evaporate to give the high HDO/H 2 O ratio.…”

Section: Other Observational Evidence Of Injection Of Water Substancementioning

confidence: 99%

Cross Tropopause Transport of Water by Mid-Latitude Deep Convective Storms: A Review

Wang¹,

Su²,

Charvát³

et al. 2011

Terr. Atmos. Ocean. Sci.

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Recent observational and numerical modeling studies of the mechanisms which transport moisture to the stratosphere by deep convective storms at mid-latitudes are reviewed. Observational evidence of the cross-tropopause transport of moisture by thunderstorms includes satellite, aircraft and ground-based data. The primary satellite evidence is taken from both conventional satellite of thunderstorm images and CloudSat vertical cloud cross-section images. The conventional satellite images show cirrus plumes above the anvil tops of some of the convective storms where the anvils are already at the tropopause level. The CloudSat image shows an indication of penetration of cirrus plume into the stratosphere. The aircraft observations consist of earlier observations of the "jumping cirrus" phenomenon reported by Fujita and recent detection of ice particles in the stratospheric air associated with deep convective storms. The ground-based observations are video camera records of the jumping cirrus phenomenon occurring at the top of thunderstorm cells. Numerical model studies of the penetrative deep convective storms were performed utilizing a three-dimensional cloud dynamical model to simulate a typical severe storm which occurred in the US Midwest region on 2 August 1981. Model results indicate two physical mechanisms that cause water to be injected into the stratosphere from the storm: (1) the jumping cirrus mechanism which is caused by the gravity wave breaking at the cloud top, and (2) an instability caused by turbulent mixing in the outer shell of the overshooting dome. Implications of the penetrative convection on global processes and a brief future outlook are discussed.

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“…This is due to the rapid and direct transport from the planetary boundary layer, where most tracers have their sources. Several studies, e.g., Fischer et al (2003), Ray et al (2004), Hanisco et al (2007) and Pittman et al (2007), report direct observational evidence for the influence of water vapor and tracers into the lower stratosphere due to deep convection at high-and mid-latitudes. Numerical studies using cloud resolving models have investigated the characteristics of TST induced by deep convection.…”

Section: Introductionmentioning

confidence: 99%

Small-scale mixing processes enhancing troposphere-to-stratosphere transport by pyro-cumulonimbus storms

et al. 2007

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Abstract. Deep convection induced by large forest fires is an efficient mechanism for transport of aerosol particles and trace gases into the upper troposphere and lower stratosphere (UT/LS). For many pyro-cumulonimbus clouds (pyroCbs) as well as other cases of severe convection without fire forcing, radiometric observations of cloud tops in the thermal infrared (IR) reveal characteristic structures, featuring a region of relatively high brightness temperatures (warm center) surrounded by a U-shaped region of low brightness temperatures.We performed a numerical simulation of a specific case study of pyroCb using a non-hydrostatic cloud resolving model with a two-moment cloud microphysics parameterization and a prognostic turbulence scheme. The model is able to reproduce the thermal IR structure as observed from satellite radiometry. Our findings establish a close link between the observed temperature pattern and small-scale mixing processes atop and downwind of the overshooting dome of the pyroCb. Such small-scale mixing processes are strongly enhanced by the formation and breaking of a stationary gravity wave induced by the overshoot. They are found to increase the stratospheric penetration of the smoke by up to almost 30 K and thus are of major significance for irreversible transport of forest fire smoke into the lower stratosphere.

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Observations of deep convective influence on stratospheric water vapor and its isotopic composition

Cited by 123 publications

References 27 publications

Dehydration of the stratosphere

Dehydration of the stratosphere

Cross Tropopause Transport of Water by Mid-Latitude Deep Convective Storms: A Review

Small-scale mixing processes enhancing troposphere-to-stratosphere transport by pyro-cumulonimbus storms

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