A New Mechanism for the Dependence of Tropical Convection on Free‐Tropospheric Humidity

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Sammanfattning

Atmospheric deep convection is responsible for transport of the most important greenhouse gas, water vapor, to the free-troposphere and for most of the precipitation on Earth. Observations show that deep convection is strongly sensitive to the amount of moisture in the low-to-midtroposphere. The current understanding is that this sensitivity is due to entrainment. In this study, it is found that over tropical oceans shallow warm anomalies, likely strong enough to hinder subsequent convection, are observed just above the boundary layer after precipitation, but only where the low-to-midtroposphere is dry. The results, showing a cold anomaly above the warm anomaly, suggest that evaporation of stratiform precipitation and subsidence warming below likely cause these temperature anomalies. Evaporation of stratiform precipitation should therefore be a topic of high priority for developing more realistic theories of convective weather phenomena and for improving climate and weather forecast models.
Originalspråkengelska
TidskriftGeophysical Research Letters
Volym45
Utgåva5
Sidor (från-till)2516–2523
Antal sidor8
ISSN0094-8276
DOI
StatusPublicerad - 16 mar 2018
MoE-publikationstypA1 Tidskriftsartikel-refererad

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  • 1172 Miljövetenskap

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@article{cdf9916727a545fb8b6b84a6f155a64b,
title = "A New Mechanism for the Dependence of Tropical Convection on Free‐Tropospheric Humidity",
abstract = "Atmospheric deep convection is responsible for transport of the most important greenhouse gas, water vapor, to the free-troposphere and for most of the precipitation on Earth. Observations show that deep convection is strongly sensitive to the amount of moisture in the low-to-midtroposphere. The current understanding is that this sensitivity is due to entrainment. In this study, it is found that over tropical oceans shallow warm anomalies, likely strong enough to hinder subsequent convection, are observed just above the boundary layer after precipitation, but only where the low-to-midtroposphere is dry. The results, showing a cold anomaly above the warm anomaly, suggest that evaporation of stratiform precipitation and subsidence warming below likely cause these temperature anomalies. Evaporation of stratiform precipitation should therefore be a topic of high priority for developing more realistic theories of convective weather phenomena and for improving climate and weather forecast models.",
keywords = "1172 Environmental sciences",
author = "M. Virman and M. Bister and Sinclair, {V. A.} and H. J{\"a}rvinen and J. R{\"a}is{\"a}nen",
year = "2018",
month = "3",
day = "16",
doi = "10.1002/2018GL077032",
language = "English",
volume = "45",
pages = "2516–2523",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
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}

A New Mechanism for the Dependence of Tropical Convection on Free‐Tropospheric Humidity. / Virman, M.; Bister, M.; Sinclair, V. A.; Järvinen, H.; Räisänen, J.

I: Geophysical Research Letters, Vol. 45, Nr. 5, 16.03.2018, s. 2516–2523.

Forskningsoutput: TidskriftsbidragArtikelVetenskapligPeer review

TY - JOUR

T1 - A New Mechanism for the Dependence of Tropical Convection on Free‐Tropospheric Humidity

AU - Virman, M.

AU - Bister, M.

AU - Sinclair, V. A.

AU - Järvinen, H.

AU - Räisänen, J.

PY - 2018/3/16

Y1 - 2018/3/16

N2 - Atmospheric deep convection is responsible for transport of the most important greenhouse gas, water vapor, to the free-troposphere and for most of the precipitation on Earth. Observations show that deep convection is strongly sensitive to the amount of moisture in the low-to-midtroposphere. The current understanding is that this sensitivity is due to entrainment. In this study, it is found that over tropical oceans shallow warm anomalies, likely strong enough to hinder subsequent convection, are observed just above the boundary layer after precipitation, but only where the low-to-midtroposphere is dry. The results, showing a cold anomaly above the warm anomaly, suggest that evaporation of stratiform precipitation and subsidence warming below likely cause these temperature anomalies. Evaporation of stratiform precipitation should therefore be a topic of high priority for developing more realistic theories of convective weather phenomena and for improving climate and weather forecast models.

AB - Atmospheric deep convection is responsible for transport of the most important greenhouse gas, water vapor, to the free-troposphere and for most of the precipitation on Earth. Observations show that deep convection is strongly sensitive to the amount of moisture in the low-to-midtroposphere. The current understanding is that this sensitivity is due to entrainment. In this study, it is found that over tropical oceans shallow warm anomalies, likely strong enough to hinder subsequent convection, are observed just above the boundary layer after precipitation, but only where the low-to-midtroposphere is dry. The results, showing a cold anomaly above the warm anomaly, suggest that evaporation of stratiform precipitation and subsidence warming below likely cause these temperature anomalies. Evaporation of stratiform precipitation should therefore be a topic of high priority for developing more realistic theories of convective weather phenomena and for improving climate and weather forecast models.

KW - 1172 Environmental sciences

U2 - 10.1002/2018GL077032

DO - 10.1002/2018GL077032

M3 - Article

VL - 45

SP - 2516

EP - 2523

JO - Geophysical Research Letters

JF - Geophysical Research Letters

SN - 0094-8276

IS - 5

ER -