Evaluation of twentieth-century Atlantic Warm Pool simulations in historical CMIP5 runs

2012 ◽  
Vol 41 (9-10) ◽  
pp. 2375-2391 ◽  
Author(s):  
Michael E. Kozar ◽  
Vasubandhu Misra
Keyword(s):  
Twentieth Century ◽  
Warm Pool ◽  
Atlantic Warm Pool

Atlantic Warm-Pool Variability in the IPCC AR4 CGCM Simulations

2012 ◽  
Vol 25 (16) ◽  
pp. 5612-5628 ◽  
Author(s):  
Hailong Liu ◽  
Chunzai Wang ◽  
Sang-Ki Lee ◽  
David Enfield
Keyword(s):  
Twentieth Century ◽  
Decadal Variability ◽  
Local Heating ◽  
Warm Pool ◽  
Shortwave Radiation ◽  
Coupled Models ◽  
Area Index ◽  
Low Level ◽  
Atlantic Warm Pool ◽  
Sst Bias

Abstract This study investigates Atlantic warm pool (AWP) variability in the twentieth century and preindustrial simulations of coupled GCMs submitted to the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). In the twentieth-century simulations, most coupled models show very weak AWP variability, represented by an AWP area index, because of the cold SST bias in the AWP. Among the IPCC models, a higher AWP SST index corresponds to increased net downward shortwave radiation and decreased low-level cloud fraction during the AWP peak season. This suggests that the cold SST bias in the AWP region is at least partly caused by an excessive amount of simulated low-level cloud, which blocks shortwave radiation from reaching the sea surface. AWP natural variability is examined in preindustrial simulations. Spectral analysis reveals that only multidecadal band variability of the AWP is significant in observations. All models successfully capture the multidecadal band, but they show that interannual and/or decadal variability is also significant. On the multidecadal time scale, the global SST difference pattern between large AWP years and small AWP years resembles the geographic pattern of the AMO for most coupled models. Observational analysis indicates that both positive ENSO phase and negative NAO phase in winter correspond to reduced trade winds in the AWP region. The westerly anomalies induced by positive ENSO and negative NAO lead to local heating and warm SST from March to May and February to April, respectively. This behavior as a known feature of anomalous AWP growth is well captured by only five models.

scholarly journals Response of Freshwater Flux and Sea Surface Salinity to Variability of the Atlantic Warm Pool

2013 ◽  
Vol 26 (4) ◽  
pp. 1249-1267 ◽  
Author(s):  
Chunzai Wang ◽  
Liping Zhang ◽  
Sang-Ki Lee
Keyword(s):  
Central America ◽  
North Atlantic ◽  
Warm Pool ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Freshwater Flux ◽  
Surface Salinity ◽  
Atlantic Warm Pool ◽  
Mean Circulation ◽  
Circulation Dynamics

Abstract The response of freshwater flux and sea surface salinity (SSS) to the Atlantic warm pool (AWP) variations from seasonal to multidecadal time scales is investigated by using various reanalysis products and observations. All of the datasets show a consistent response for all time scales: A large (small) AWP is associated with a local freshwater gain (loss) to the ocean, less (more) moisture transport across Central America, and a local low (high) SSS. The moisture budget analysis demonstrates that the freshwater change is dominated by the atmospheric mean circulation dynamics, while the effect of thermodynamics is of secondary importance. Further decomposition points out that the contribution of the mean circulation dynamics primarily arises from its divergent part, which mainly reflects the wind divergent change in the low level as a result of SST change. In association with a large (small) AWP, warmer (colder) than normal SST over the tropical North Atlantic can induce anomalous low-level convergence (divergence), which favors anomalous ascent (decent) and thus generates more (less) precipitation. On the other hand, a large (small) AWP weakens (strengthens) the trade wind and its associated westward moisture transport to the eastern North Pacific across Central America, which also favors more (less) moisture residing in the Atlantic and hence more (less) precipitation. The results imply that variability of freshwater flux and ocean salinity in the North Atlantic associated with the AWP may have the potential to affect the Atlantic meridional overturning circulation.

scholarly journals The North Pacific blob acts to increase the predictability of the Atlantic warm pool

2021 ◽  
Author(s):  
Yusen Liu ◽  
Cheng Sun ◽  
Fred Kucharski ◽  
Jianping Li ◽  
Chunzai Wang ◽  
...  
Keyword(s):  
North Pacific ◽  
Warm Pool ◽  
The North ◽  
Atlantic Warm Pool ◽  
The North Pacific

The Track Integrated Kinetic Energy of Atlantic Tropical Cyclones

2013 ◽  
Vol 141 (7) ◽  
pp. 2383-2389 ◽  
Author(s):  
V. Misra ◽  
S. DiNapoli ◽  
M. Powell
Keyword(s):  
Tropical Cyclone ◽  
Kinetic Energy ◽  
Tropical Cyclones ◽  
Warm Pool ◽  
Equatorial Pacific ◽  
Interannual Variations ◽  
Tropical Atlantic ◽  
Cyclone Activity ◽  
Atlantic Warm Pool ◽  
Atlantic Tropical Cyclone

Abstract In this paper the concept of track integrated kinetic energy (TIKE) is introduced as a measure of seasonal Atlantic tropical cyclone activity and applied to seasonal variability in the Atlantic. It is similar in concept to the more commonly used accumulated cyclone energy (ACE) with an important difference that in TIKE the integrated kinetic energy (IKE) is accumulated for the life span of the Atlantic tropical cyclone. The IKE is, however, computed by volume integrating the 10-m level sustained winds of tropical strength or higher quadrant by quadrant, while ACE uses the maximum sustained winds only without accounting for the structure of the storm. In effect TIKE accounts for the intensity, duration, and size of the tropical cyclones. In this research, the authors have examined the seasonality and the interannual variations of the seasonal Atlantic TIKE over a period of 22 yr from 1990 to 2011. It is found that the Atlantic TIKE climatologically peaks in the month of September and the frequency of storms with the largest TIKE are highest in the eastern tropical Atlantic. The interannual variations of the Atlantic TIKE reveal that it is likely influenced by SST variations in the equatorial Pacific and in the Atlantic Oceans. The SST variations in the central equatorial Pacific are negatively correlated with the contemporaneous seasonal (June–November) TIKE. The size of the Atlantic warm pool (AWP) is positively correlated with seasonal TIKE.

Air-sea interaction over the Atlantic warm pool in the NCEP CFS

2009 ◽  
Vol 36 (15) ◽  
pp. n/a-n/a ◽  
Author(s):  
Vasubandhu Misra ◽  
Steven Chan ◽  
Renguang Wu ◽  
E. Chassignet
Keyword(s):  
Warm Pool ◽  
Atlantic Warm Pool ◽  
Ncep Cfs

scholarly journals Impact of the Atlantic Warm Pool on the Summer Climate of the Western Hemisphere

2007 ◽  
Vol 20 (20) ◽  
pp. 5021-5040 ◽  
Author(s):  
Chunzai Wang ◽  
Sang-ki Lee ◽  
David B. Enfield
Keyword(s):  
North Atlantic ◽  
Moisture Transport ◽  
Caribbean Sea ◽  
Warm Pool ◽  
Western Hemisphere ◽  
Trade Winds ◽  
The North ◽  
Atlantic Warm Pool ◽  
Tropical North Atlantic ◽  
The Caribbean

Abstract The Atlantic warm pool (AWP) is a large body of warm water that comprises the Gulf of Mexico, the Caribbean Sea, and the western tropical North Atlantic. Located to its northeastern side is the North Atlantic subtropical high (NASH), which produces the tropical easterly trade winds. The easterly trade winds carry moisture from the tropical North Atlantic into the Caribbean Sea, where the flow intensifies, forming the Caribbean low-level jet (CLLJ). The CLLJ then splits into two branches: one turning northward and connecting with the Great Plains low-level jet (GPLLJ), and the other continuing westward across Central America into the eastern North Pacific. The easterly CLLJ and its westward moisture transport are maximized in the summer and winter, whereas they are minimized in the fall and spring. This semiannual feature results from the semiannual variation of sea level pressure in the Caribbean region owing to the westward extension and eastward retreat of the NASH. The NCAR Community Atmospheric Model and observational data are used to investigate the impact of the climatological annual mean AWP on the summer climate of the Western Hemisphere. Two groups of the model ensemble runs with and without the AWP are performed and compared. The model results show that the effect of the AWP is to weaken the summertime NASH, especially at its southwestern edge. The AWP also strengthens the summertime continental low over the North American monsoon region. In response to these pressure changes, the CLLJ and its moisture transport are weakened, but its semiannual feature does not disappear. The weakening of the easterly CLLJ increases (decreases) moisture convergence to its upstream (downstream) and thus enhances (suppresses) rainfall in the Caribbean Sea (in the far eastern Pacific west of Central America). Model runs show that the AWP’s effect is to always weaken the southerly GPLLJ. However, the AWP strengthens the GPLLJ’s northward moisture transport in the summer because the AWP-induced increase of specific humidity overcomes the weakening of southerly wind, and vice versa in the fall. Finally, the AWP reduces the tropospheric vertical wind shear in the main development region that favors hurricane formation and development during August–October.

The rendition of the Atlantic Warm Pool in the reanalyses

2012 ◽  
Vol 41 (2) ◽  
pp. 517-532 ◽  
Author(s):  
Vasubandhu Misra ◽  
Ashley Stroman ◽  
Steven DiNapoli
Keyword(s):  
Warm Pool ◽  
Atlantic Warm Pool

scholarly journals Corals record persistent multidecadal SST variability in the Atlantic Warm Pool since 1775 AD

2012 ◽  
Vol 27 (3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Luis Fernando Vásquez-Bedoya ◽  
Anne L. Cohen ◽  
Delia W. Oppo ◽  
Paul Blanchon
Keyword(s):  
Warm Pool ◽  
Sst Variability ◽  
Atlantic Warm Pool
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