Mechanisms regulating sea-surface temperatures and deep convection in the tropics

1999 ◽  
Vol 26 (8) ◽  
pp. 1019-1022 ◽  
Author(s):  
Y. C. Sud ◽  
G. K. Walker ◽  
K. -M. Lau
Keyword(s):  
Deep Convection ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Surface Temperatures ◽  
The Tropics

Leading Tropical Modes Associated with Interannual and Multidecadal Fluctuations in North Atlantic Hurricane Activity

2006 ◽  
Vol 19 (4) ◽  
pp. 590-612 ◽  
Author(s):  
Gerald D. Bell ◽  
Muthuvel Chelliah
Keyword(s):  
West African Monsoon ◽  
West African ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
African Monsoon ◽  
Atlantic Hurricane ◽  
Enso Teleconnections ◽  
Surface Temperatures ◽  
Hurricane Activity ◽  
The Tropics

Abstract Interannual and multidecadal extremes in Atlantic hurricane activity are shown to result from a coherent and interrelated set of atmospheric and oceanic conditions associated with three leading modes of climate variability in the Tropics. All three modes are related to fluctuations in tropical convection, with two representing the leading multidecadal modes of convective rainfall variability, and one representing the leading interannual mode (ENSO). The tropical multidecadal modes are shown to link known fluctuations in Atlantic hurricane activity, West African monsoon rainfall, and Atlantic sea surface temperatures, to the Tropics-wide climate variability. These modes also capture an east–west seesaw in anomalous convection between the West African monsoon region and the Amazon basin, which helps to account for the interhemispheric symmetry of the 200-hPa streamfunction anomalies across the Atlantic Ocean and Africa, the 200-hPa divergent wind anomalies, and both the structure and spatial scale of the low-level tropical wind anomalies, associated with multidecadal extremes in Atlantic hurricane activity. While there are many similarities between the 1950–69 and 1995–2004 periods of above-normal Atlantic hurricane activity, important differences in the tropical climate are also identified, which indicates that the above-normal activity since 1995 does not reflect an exact return to conditions seen during the 1950s–60s. In particular, the period 1950–69 shows a strong link to the leading tropical multidecadal mode (TMM), whereas the 1995–2002 period is associated with a sharp increase in amplitude of the second leading tropical multidecadal mode (TMM2). These differences include a very strong West African monsoon circulation and near-average sea surface temperatures across the central tropical Atlantic during 1950–69, compared with a modestly enhanced West African monsoon and exceptionally warm Atlantic sea surface temperatures during 1995–2004. It is shown that the ENSO teleconnections and impacts on Atlantic hurricane activity can be substantially masked or accentuated by the leading multidecadal modes. This leads to the important result that these modes provide a substantially more complete view of the climate control over Atlantic hurricane activity during individual seasons than is afforded by ENSO alone. This result applies to understanding differences in the “apparent” ENSO teleconnections not only between the above- and below-normal hurricane decades, but also between the two sets of above-normal hurricane decades.

Effects of doubled CO2on tropical sea surface temperatures (SSTs) for onset of deep convection and maximum SST: Simulations based inferences

2008 ◽  
Vol 35 (12) ◽  
pp. n/a-n/a ◽  
Author(s):  
Y. C. Sud ◽  
G. K. Walker ◽  
Y. P. Zhou ◽  
Gavin A. Schmidt ◽  
K.-M. Lau ◽  
...  
Keyword(s):  
Deep Convection ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Surface Temperatures ◽  
Tropical Sea

scholarly journals Conquering Uncertainties in Tropical Climate Forecasts

Eos ◽  
2015 ◽  
Vol 96 ◽  
Author(s):  
Eric Betz
Keyword(s):  
Tropical Climate ◽  
Atmospheric Temperature ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Temperature Trends ◽  
Surface Temperatures ◽  
Climate Forecasts ◽  
The Tropics

The key to better predictions of atmospheric temperature trends in the tropics may lie in more accurate measurements of sea surface temperatures.

scholarly journals Rapid Intensification of Typhoon Mujigae (2015) under Different Sea Surface Temperatures: Structural Changes Leading to Rapid Intensification

2018 ◽  
Vol 75 (12) ◽  
pp. 4313-4335 ◽  
Author(s):  
Xiaomin Chen ◽  
Ming Xue ◽  
Juan Fang
Keyword(s):  
Structural Changes ◽  
Inner Core ◽  
Deep Convection ◽  
Vertical Wind Shear ◽  
Surface Friction ◽  
Sea Surface ◽  
Rapid Intensification ◽  
Sea Surface Temperatures ◽  
Vertical Alignment ◽  
Surface Temperatures

Abstract The notable prelandfall rapid intensification (RI) of Typhoon Mujigae (2015) over abnormally warm water with moderate vertical wind shear (VWS) is investigated by performing a set of full-physics model simulations initialized with different sea surface temperatures (SSTs). While all experiments can reproduce RI, tropical cyclones (TCs) in cooler experiments initiate the RI 13 h later than those in warmer experiments. A comparison of structural changes preceding RI onset in two representative experiments with warmer and cooler SSTs (i.e., CTL and S1) indicates that both TCs undergo similar vertical alignment despite the moderate VWS. RI onset in CTL occurs ~8 h before the full vertical alignment, while that in S1 occurs ~5 h after. In both experiments precipitation becomes more symmetrically distributed around the vortex as vortex tilt decreases. In CTL, precipitation symmetricity is higher in the inner-core region, particularly for stratiform precipitation. All experiments indicate that RI onset occurs when the radius of maximum wind (RMW) contraction reaches a certain degree measured in terms of local Rossby number. The contraction occurs much earlier in CTL, leading to earlier RI. These results suggest that vertical alignment, albeit necessary, is not an effective RI indicator under different SSTs, while a more immediate cause of RI is the formation of a strong/compact inner core with high precipitation symmetry. Diagnoses using the Sawyer–Eliassen equation indicate that in CTL the enhanced microphysical diabatic heating of additional midlevel and deep convection along with surface friction contribute to stronger boundary layer inflow near/inside the RMW, facilitating earlier RMW contraction.

scholarly journals Tropical Convection in the Caribbean and Surrounding Region during a Regional, Warming Sea-Surface Temperature Period, 1982–2020

Hydrology ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 56
Author(s):  
Equisha Glenn ◽  
Thomas M. Smith ◽  
Jose M. Gálvez ◽  
Michel Davison ◽  
Keneshia Hibbert ◽  
...  
Keyword(s):  
Deep Convection ◽  
Tropical Convection ◽  
Sea Surface ◽  
Caribbean Region ◽  
Precipitation Pattern ◽  
Sea Surface Temperatures ◽  
Regional Warming ◽  
Surface Temperatures ◽  
The Caribbean ◽  
Heat And Moisture

Warming sea-surface temperatures (SSTs) have implications for the climate-sensitive Caribbean region, including potential impacts on precipitation. SSTs have been shown to influence deep convection and rainfall, thus understanding the impacts of warming SSTs is important for predicting regional hydrometeorological conditions. This study investigates the long-term annual and seasonal trends in convection using the Galvez-Davison Index (GDI) for tropical convection from 1982–2020. The GDI is used to describe the type and potential for precipitation events characterized by sub-indices that represent heat and moisture availability, cool/warm mid-levels at 500 hPa, and subsidence inversion, which drive the regional Late, Early, and Dry Rainfall Seasons, respectively. Results show that regional SSTs are warming annually and per season, while regionally averaged GDI values are decreasing annually and for the Dry Season. Spatial analyses show the GDI demonstrates higher, statistically significant correlations with precipitation across the region than with sea-surface temperatures, annually and per season. Moreover, the GDI climatology results show that regional convection exhibits a bimodal pattern resembling the characteristic bimodal precipitation pattern experienced in many parts of the Caribbean and surrounding region. However, the drivers of these conditions need further investigation as SSTs continue to rise while the region experiences a drying trend.

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