Abstract
Cold pools dominate the surface temperature variability observed over the central Indian Ocean (0°, 80°E) for 2 months of research cruise observations in the Dynamics of the Madden-Julian Oscillation (DYNAMO) experiment in October-December 2011. Cold pool fronts are identified by a rapid drop of temperature. Air in cold pools is slightly drier than the boundary layer (BL). Consistent with previous studies, cold pools attain wet-bulb potential temperatures representative of saturated downdrafts originating from the lower midtroposphere. Wind and surface fluxes increase, and rain is most likely within the ~20-min cold pool front. Greatest integrated water vapor and liquid follow the front. Temperature and velocity fluctuations shorter than 6 min achieve 90% of the surface latent and sensible heat flux in cold pools. The temperature of the cold pools recovers in about 20 min, chiefly by mixing at the top of the shallow cold wake layer, rather than by surface flux. Analysis of conserved variables shows mean BL air is composed of 51% air entrained from the BL top (800 m), 22% saturated downdrafts, and 27% air at equilibrium with the ocean surface. The number of cold pools, and their contribution to the BL heat and moisture, nearly doubles in the convectively active phase compared to the suppressed phase of the Madden-Julian oscillation.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1149-1168 |
| Number of pages | 20 |
| Journal | Journal of the Atmospheric Sciences |
| Volume | 74 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 1 2017 |
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Keywords
- Atmosphere-ocean interaction
- Boundary layer
- Cold pools
- Madden-Julian oscillation
- Ship observations
- Tropics
ASJC Scopus subject areas
- Atmospheric Science
Cite this
Cold pools and their influence on the tropical marine boundary layer. / de Szoeke, Simon P.; Skyllingstad, Eric D.; Zuidema, Paquita; Chandra, Arunchandra S.
In: Journal of the Atmospheric Sciences, Vol. 74, No. 4, 01.04.2017, p. 1149-1168.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Cold pools and their influence on the tropical marine boundary layer
AU - de Szoeke, Simon P.
AU - Skyllingstad, Eric D.
AU - Zuidema, Paquita
AU - Chandra, Arunchandra S.
PY - 2017/4/1
Y1 - 2017/4/1
N2 - Cold pools dominate the surface temperature variability observed over the central Indian Ocean (0°, 80°E) for 2 months of research cruise observations in the Dynamics of the Madden-Julian Oscillation (DYNAMO) experiment in October-December 2011. Cold pool fronts are identified by a rapid drop of temperature. Air in cold pools is slightly drier than the boundary layer (BL). Consistent with previous studies, cold pools attain wet-bulb potential temperatures representative of saturated downdrafts originating from the lower midtroposphere. Wind and surface fluxes increase, and rain is most likely within the ~20-min cold pool front. Greatest integrated water vapor and liquid follow the front. Temperature and velocity fluctuations shorter than 6 min achieve 90% of the surface latent and sensible heat flux in cold pools. The temperature of the cold pools recovers in about 20 min, chiefly by mixing at the top of the shallow cold wake layer, rather than by surface flux. Analysis of conserved variables shows mean BL air is composed of 51% air entrained from the BL top (800 m), 22% saturated downdrafts, and 27% air at equilibrium with the ocean surface. The number of cold pools, and their contribution to the BL heat and moisture, nearly doubles in the convectively active phase compared to the suppressed phase of the Madden-Julian oscillation.
AB - Cold pools dominate the surface temperature variability observed over the central Indian Ocean (0°, 80°E) for 2 months of research cruise observations in the Dynamics of the Madden-Julian Oscillation (DYNAMO) experiment in October-December 2011. Cold pool fronts are identified by a rapid drop of temperature. Air in cold pools is slightly drier than the boundary layer (BL). Consistent with previous studies, cold pools attain wet-bulb potential temperatures representative of saturated downdrafts originating from the lower midtroposphere. Wind and surface fluxes increase, and rain is most likely within the ~20-min cold pool front. Greatest integrated water vapor and liquid follow the front. Temperature and velocity fluctuations shorter than 6 min achieve 90% of the surface latent and sensible heat flux in cold pools. The temperature of the cold pools recovers in about 20 min, chiefly by mixing at the top of the shallow cold wake layer, rather than by surface flux. Analysis of conserved variables shows mean BL air is composed of 51% air entrained from the BL top (800 m), 22% saturated downdrafts, and 27% air at equilibrium with the ocean surface. The number of cold pools, and their contribution to the BL heat and moisture, nearly doubles in the convectively active phase compared to the suppressed phase of the Madden-Julian oscillation.
KW - Atmosphere-ocean interaction
KW - Boundary layer
KW - Cold pools
KW - Madden-Julian oscillation
KW - Ship observations
KW - Tropics
UR - http://www.scopus.com/inward/record.url?scp=85016776339&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85016776339&partnerID=8YFLogxK
U2 - 10.1175/JAS-D-16-0264.1
DO - 10.1175/JAS-D-16-0264.1
M3 - Article
AN - SCOPUS:85016776339
VL - 74
SP - 1149
EP - 1168
JO - Journals of the Atmospheric Sciences
JF - Journals of the Atmospheric Sciences
SN - 0022-4928
IS - 4
ER -