Abstract
Bimodally distributed column water vapor (CWV) indicates a well-defined moist regime in the Tropics, above a margin value near 48 kg m-2 in current climate (about 80% of column saturation). Maps reveal this margin as a meandering, sinuous synoptic contour bounding broad plateaus of the moist regime. Within these plateaus, convective storms of distinctly smaller convective and mesoscales occur sporadically. Satellite data composites across the poleward most margin reveal its sharpness, despite the crude averaging: precipitation doubles within 100 km, marked by both enhancement and deepening of cloudiness. Transported patches and filaments of the moist regime cause consequential precipitation events within and beyond the Tropics. Distinguishing synoptic flows that cross the margin from flows that move the margin is made possible by a novel satellite-based Lagrangian CWV tendency estimate. Climate models do not reliably reproduce the observed bimodal distribution, so studying the moist mode's maintenance processes and the margin-zone air mass transformations, guided by the Lagrangian tendency product, might importantly constrain model moist process treatments.
| Original language | English (US) |
|---|---|
| Journal | Geophysical Research Letters |
| DOIs | |
| State | Accepted/In press - Jan 1 2018 |
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Keywords
- Bimodality
- Column water vapor
- Convective processes
- Precipitable water
- Regimes
- Tropical convection
ASJC Scopus subject areas
- Geophysics
- Earth and Planetary Sciences(all)
Cite this
The Meandering Margin of the Meteorological Moist Tropics. / Mapes, Brian E; Chung, Eui Seok; Hannah, Walter M.; Masunaga, Hirohiko; Wimmers, Anthony J.; Velden, Christopher S.
In: Geophysical Research Letters, 01.01.2018.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The Meandering Margin of the Meteorological Moist Tropics
AU - Mapes, Brian E
AU - Chung, Eui Seok
AU - Hannah, Walter M.
AU - Masunaga, Hirohiko
AU - Wimmers, Anthony J.
AU - Velden, Christopher S.
PY - 2018/1/1
Y1 - 2018/1/1
N2 - Bimodally distributed column water vapor (CWV) indicates a well-defined moist regime in the Tropics, above a margin value near 48 kg m-2 in current climate (about 80% of column saturation). Maps reveal this margin as a meandering, sinuous synoptic contour bounding broad plateaus of the moist regime. Within these plateaus, convective storms of distinctly smaller convective and mesoscales occur sporadically. Satellite data composites across the poleward most margin reveal its sharpness, despite the crude averaging: precipitation doubles within 100 km, marked by both enhancement and deepening of cloudiness. Transported patches and filaments of the moist regime cause consequential precipitation events within and beyond the Tropics. Distinguishing synoptic flows that cross the margin from flows that move the margin is made possible by a novel satellite-based Lagrangian CWV tendency estimate. Climate models do not reliably reproduce the observed bimodal distribution, so studying the moist mode's maintenance processes and the margin-zone air mass transformations, guided by the Lagrangian tendency product, might importantly constrain model moist process treatments.
AB - Bimodally distributed column water vapor (CWV) indicates a well-defined moist regime in the Tropics, above a margin value near 48 kg m-2 in current climate (about 80% of column saturation). Maps reveal this margin as a meandering, sinuous synoptic contour bounding broad plateaus of the moist regime. Within these plateaus, convective storms of distinctly smaller convective and mesoscales occur sporadically. Satellite data composites across the poleward most margin reveal its sharpness, despite the crude averaging: precipitation doubles within 100 km, marked by both enhancement and deepening of cloudiness. Transported patches and filaments of the moist regime cause consequential precipitation events within and beyond the Tropics. Distinguishing synoptic flows that cross the margin from flows that move the margin is made possible by a novel satellite-based Lagrangian CWV tendency estimate. Climate models do not reliably reproduce the observed bimodal distribution, so studying the moist mode's maintenance processes and the margin-zone air mass transformations, guided by the Lagrangian tendency product, might importantly constrain model moist process treatments.
KW - Bimodality
KW - Column water vapor
KW - Convective processes
KW - Precipitable water
KW - Regimes
KW - Tropical convection
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UR - http://www.scopus.com/inward/citedby.url?scp=85041201326&partnerID=8YFLogxK
U2 - 10.1002/2017GL076440
DO - 10.1002/2017GL076440
M3 - Article
JO - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
ER -