scholarly journals Observed and projected changes in the annual cycle of Southern Hemisphere baroclinicity for storm formation

2011 ◽  
Keyword(s):  
Southern Hemisphere ◽  
Annual Cycle ◽  
Projected Changes

CMIP3 projected changes in the annual cycle of the South American Monsoon

2009 ◽  
Vol 98 (3-4) ◽  
pp. 331-357 ◽  
Author(s):  
Anji Seth ◽  
Maisa Rojas ◽  
Sara A. Rauscher
Keyword(s):  
Annual Cycle ◽  
South American ◽  
The South ◽  
South American Monsoon ◽  
Projected Changes

Simulation of Present-Day and Twenty-First-Century Energy Budgets of the Southern Oceans

2010 ◽  
Vol 23 (2) ◽  
pp. 440-454 ◽  
Author(s):  
Kevin E. Trenberth ◽  
John T. Fasullo
Keyword(s):  
Southern Hemisphere ◽  
Cloud Cover ◽  
Climate Models ◽  
Global Climate ◽  
Strong Relationship ◽  
Global Climate Models ◽  
Storm Tracks ◽  
Energy Budgets ◽  
Poleward Shift ◽  
Projected Changes

Abstract The energy budget of the modern-day Southern Hemisphere is poorly simulated in both state-of-the-art reanalyses and coupled global climate models. The ocean-dominated Southern Hemisphere has low surface reflectivity and therefore its albedo is particularly sensitive to cloud cover. In modern-day climates, mainly because of systematic deficiencies in cloud and albedo at mid- and high latitudes, too much solar radiation enters the ocean. Along with too little radiation absorbed at lower latitudes because of clouds that are too bright, unrealistically weak poleward transports of energy by both the ocean and atmosphere are generally simulated in the Southern Hemisphere. This implies too little baroclinic eddy development and deficient activity in storm tracks. However, projections into the future by coupled climate models indicate that the Southern Ocean features a robust and unique increase in albedo, related to clouds, in association with an intensification and poleward shift in storm tracks that is not observed at any other latitude. Such an increase in cloud may be untenable in nature, as it is likely precluded by the present-day ubiquitous cloud cover that models fail to capture. There is also a remarkably strong relationship between the projected changes in clouds and the simulated current-day cloud errors. The model equilibrium climate sensitivity is also significantly negatively correlated with the Southern Hemisphere energy errors, and only the more sensitive models are in the range of observations. As a result, questions loom large about how the Southern Hemisphere will actually change as global warming progresses, and a better simulation of the modern-day climate is an essential first step.

scholarly journals CMIP5 Projected Changes in the Annual Cycle of Indian Monsoon Rainfall

Climate ◽  
2016 ◽  
Vol 4 (1) ◽  
pp. 14 ◽  
Author(s):  
Pravat Jena ◽  
Sarita Azad ◽  
Madhavan Rajeevan
Keyword(s):  
Annual Cycle ◽  
Monsoon Rainfall ◽  
Indian Monsoon ◽  
Indian Monsoon Rainfall ◽  
Projected Changes

scholarly journals Historical and projected changes in the Southern Hemisphere surface westerlies

2020 ◽  
Author(s):  
Rishav Goyal ◽  
Alexander Sen Gupta ◽  
Martin Jucker ◽  
Matthew H. England
Keyword(s):  
Southern Hemisphere ◽  
Hemisphere Surface ◽  
Projected Changes

scholarly journals Projected Changes in the Annual Cycle of High-Intensity Precipitation Events over West Africa for the Late Twenty-First Century*

2015 ◽  
Vol 28 (16) ◽  
pp. 6475-6488 ◽  
Author(s):  
Mouhamadou Bamba Sylla ◽  
Filippo Giorgi ◽  
Jeremy S. Pal ◽  
Peter Gibba ◽  
Ibourahima Kebe ◽  
...  
Keyword(s):  
West Africa ◽  
Annual Cycle ◽  
High Intensity ◽  
Daily Precipitation ◽  
Monsoon Season ◽  
First Century ◽  
Increased Risk ◽  
Twenty First Century ◽  
Projected Changes ◽  
Precipitation Events

Abstract In this study, the response of the annual cycle of high-intensity daily precipitation events over West Africa to anthropogenic greenhouse gas for the late twenty-first century is investigated using an ensemble of high-resolution regional climate model experiments. For the present day, the RCM ensemble substantially improves the simulation of the annual cycle for various precipitation statistics compared to the driving Earth system models. The late-twenty-first-century projected changes in mean precipitation exhibit a delay of the monsoon season, consistent with previous studies. In addition, these projections indicate a prevailing decrease in frequency but increase in intensity of very wet events, particularly in the premonsoon and early mature monsoon stages, more pronounced over the Sahel and in RCP8.5 than the Gulf of Guinea and in RCP4.5. This is due to the presence of stronger moisture convergence in the boundary layer that sustains intense precipitation once convection is initiated. The premonsoon season experiences the largest changes in daily precipitation statistics, particularly toward an increased risk of drought associated with a decrease in mean precipitation and frequency of wet days and an increased risk of flood associated with very wet events. Both of these features can produce significant stresses on important sectors such as agriculture and water resources at a time of the year (e.g., the monsoon onset) where such stresses can have stronger impacts. The results thus point toward the importance of analyzing changes of precipitation characteristics as a function of the regional seasonal and subseasonal cycles of rainfall.

scholarly journals Diagnosing the Annual Cycle Modes in the Tropical Atlantic Ocean Using a Directly Coupled Atmosphere–Ocean GCM

2006 ◽  
Vol 19 (20) ◽  
pp. 5319-5342 ◽  
Author(s):  
David G. DeWitt ◽  
Edwin K. Schneider
Keyword(s):  
Heat Flux ◽  
Southern Hemisphere ◽  
Vertical Velocity ◽  
Annual Cycle ◽  
General Circulation ◽  
Model Simulation ◽  
Circulation Model ◽  
Surface Fluxes ◽  
Thermocline Depth ◽  
Tropical Atlantic

Abstract The annual cycle of sea surface temperature (SST) in the tropical Atlantic of a directly coupled atmosphere–ocean general circulation model (CGCM) is decomposed into the parts forced by different surface fluxes (denoted as modes) for the two extreme months of March and August using forced ocean experiments. Almost all previous diagnostic work of the forcing of the SST annual cycle in the Atlantic has concentrated on the near-equatorial region. Here, the annual cycle is examined within the latitude range of 25°S–25°N to facilitate comparison with the interannual variability. The structure of the response to the different surface flux forcings bears some resemblance to the interannual SST modes in the tropical Atlantic, which are diagnosed using rotated empirical orthogonal function (REOF) analysis. Diagnosis of the forcing of the annual cycle modes and the interannual modes shows that they do not always have a common cause. Hence, the simple interpretation that the leading interannual modes are perturbations to the annual cycle is not always valid. In particular, the equatorial SST annual cycle mode is primarily driven by variations in vertical velocity while the equatorial interannual mode is associated with eastward-propagating thermocline anomalies and is forced by both thermocline anomalies and vertical velocity anomalies. As for the interannual modes, there exist off-equatorial annual cycle modes in both the Northern and Southern Hemispheres. The annual cycle off-equatorial mode in both hemispheres is shown to be primarily driven by heat flux variations. The Southern Hemisphere interannual mode is primarily driven by heat flux variations while the Northern Hemisphere interannual mode shows a strong influence of thermocline depth anomalies. In addition, the Southern Hemisphere interannual mode is centered about 10° south of the annual cycle mode. An interannual mode that has maximum variability along the South American coast south of the equator is shown to be associated with thermocline depth anomalies. This interannual mode has no analog in the annual cycle modes. The coupled model simulation of the annual cycle is found to be fairly realistic so that the results presented here could have applicability to the observed Atlantic.

Projected changes in the annual cycle of precipitation over central Asia by CMIP5 models

2018 ◽  
Vol 38 (15) ◽  
pp. 5589-5604 ◽  
Author(s):  
Xiaojing Yu ◽  
Yong Zhao ◽  
Xiaojiao Ma ◽  
Junqiang Yao ◽  
Hongjun Li
Keyword(s):  
Central Asia ◽  
Annual Cycle ◽  
Cmip5 Models ◽  
Projected Changes
Sign in / Sign up

Export Citation Format

Share Document