Topic
Tropical Easterly Jet
About: Tropical Easterly Jet is a research topic. Over the lifetime, 262 publications have been published within this topic receiving 14110 citations.
Papers published on a yearly basis
Papers
TL;DR: In this article, a thorough description of observed monsoon variability and the physical processes that are thought to be important is presented, and some strategies that may help achieve improvement are discussed.
Abstract: The Tropical Ocean-Global Atmosphere (TOGA) program sought to determine the predictability of the coupled ocean-atmosphere system. The World Climate Research Programme's (WCRP) Global Ocean-Atmosphere-Land System (GOALS) program seeks to explore predictability of the global climate system through investigation of the major planetary heat sources and sinks, and interactions between them. The Asian-Australian monsoon system, which undergoes aperiodic and high amplitude variations on intraseasonal, annual, biennial and interannual timescales is a major focus of GOALS. Empirical seasonal forecasts of the monsoon have been made with moderate success for over 100 years. More recent modeling efforts have not been successful. Even simulation of the mean structure of the Asian monsoon has proven elusive and the observed ENSO-monsoon relationships has been difficult to replicate. Divergence in simulation skill occurs between integrations by different models or between members of ensembles of the same model. This degree of spread is surprising given the relative success of empirical forecast techniques. Two possible explanations are presented: difficulty in modeling the monsoon regions and nonlinear error growth due to regional hydrodynamical instabilities. It is argued that the reconciliation of these explanations is imperative for prediction of the monsoon to be improved. To this end, a thorough description of observed monsoon variability and the physical processes that are thought to be important is presented. Prospects of improving prediction and some strategies that may help achieve improvement are discussed.
2,946 citations
TL;DR: Evidence is presented to suggest that variability of rainfall in the Sahel results from the response of the African summer monsoon to oceanic forcing, amplified by land-atmosphere interaction.
Abstract: We present evidence, based on an ensemble of integrations with NSIPP1 (version 1 of the atmospheric general circulation model developed at NASA's Goddard Space Flight Center in the framework of the Seasonal-to-Interannual Prediction Project) forced only by the observed record of sea surface temperature from 1930 to 2000, to suggest that variability of rainfall in the Sahel results from the response of the African summer monsoon to oceanic forcing, amplified by land-atmosphere interaction. The recent drying trend in the semiarid Sahel is attributed to warmer-than-average low-latitude waters around Africa, which, by favoring the establishment of deep convection over the ocean, weaken the continental convergence associated with the monsoon and engender widespread drought from Senegal to Ethiopia.
1,128 citations
TL;DR: In this paper, the spectral analysis of long observational records has been used to define the elements of a monsoon system and its oscillations are determined from spectral analysis from long observations.
Abstract: In this paper the elements of a monsoon system are defined, and its oscillations are determined from spectral analysis of long observational records. The elements of the monsoon system include pressure of the monsoon trough, pressure of the Mascarene high, cross-equatorial low-level jet, Tibetan high, tropical easterly jet, monsoon cloud cover, monsoon rainfall, dry static stability of the lower troposphere, and moist static stability of the lower troposphere. The summer monsoon months over India during normal monsoon rainfall years are considered as guidelines in the selection of data for the period of this study. The salient result of this study is that there seems to exist a quasi-biweekly oscillation in almost all of the elements of the monsoon system. For some of these elements, such as the surface pressure field, monsoon rainfall, low-level cross-equatorial jet and monsoon cloudiness, the amplitude of this oscillation in quasi-biweekly range is very pronounced. For the spectral representati...
707 citations
Book•
1 Jan 1985
TL;DR: In this article, the authors present a model for the Indian Summer Monsoon and show that it is composed of three stages: Diurnal Marches of Sea-Air Exchange, Cloudiness, and Precipitation.
Abstract: 1. Introduction.- References.- 2. Diurnal Forcings and Local Circulations.- 2.1. Insolation and Heat Budget Forcing.- 2.2. Atmospheric Tides.- 2.3. Circulations on the Local and Meso-Scale.- 2.4. Diurnal Marches of Sea-Air Exchange, Cloudiness, and Precipitation.- 2.5. Synthesis.- References.- 3. Planetary Scale Atmospheric Circulation.- 3.1. Mean Meridional Distribution of Temperature and Humidity.- 3.2. Zonal Wind Regime.- 3.3. Mean Meridional Circulation.- 3.4. Maintenance of the Global Circulation: Angular Momentum.- 3.5. Maintenance of the Global Circulation: Kinetic Energy.- 3.6. Synthesis.- References.- 4. Ocean Circulation.- 4.1. Wind Stress and Motion Field in the Upper Ocean.- 4.2. The Subtropical Gyres.- 4.3. Equatorial Current Systems.- 4.3.1. Overview of Surface Circulation.- 4.3.2. Balance of Forces.- 4.3.3. The North Equatorial Countercurrent.- 4.3.4. Wind Stress, Vertical Motion, Thermocline and Surface Topography.- 4.3.5. The Equatorial Undercurrent.- 4.3.6. Equatorial Waves and Remote Forcing.- 4.3.7. Recent Discoveries of Subsurface Currents.- 4.4. The Monsoon Ocean.- 4.5. Deep Circulation.- 4.6. Synthesis.- References.- 5. Heat and Water Budgets.- 5.1. Basic Theory.- 5.2. Net Radiation at the Top of the Atmosphere.- 5.3. Oceanic Heat Budget.- 5.4. Atmospheric Heat Budget.- 5.5. Water Budget.- 5.6. Relative Roles of Oceanic Versus Atmospheric Heat Transports.- 5.7. Synthesis.- References.- 6. Regional Circulation Systems.- 6.1. Overview of the Global Tropics.- 6.2. Jet Streams.- 6.2.1. Basic Dynamics.- 6.2.2. Subtropical Westerly Jet.- 6.2.3. Tropical Easterly Jet.- 6.2.4. West African Mid-Tropospheric Jet.- 6.2.5. East African Low Level Jet.- 6.3. Subtropical Highs.- 6.4. Trades.- 6.5. Trade Inversion.- 6.5.1. Spatial Patterns.- 6.5.2. Origin and Maintenance.- 6.5.3. Climatic Implications.- 6.6. Mid-Tropospheric Inversions.- 6.7. Equatorial Trough Zone.- 6.7.1. The Large-Scale Setting.- 6.7.2. Structure of the Intertropical Convergence Zone.- 6.7.2.1. Atlantic and Pacific Oceans.- 6.7.2.2. Indian Ocean.- 6.7.2.3. Africa.- 6.7.2.4. On Atmospheric and Oceanic Controls.- 6.7.3. Dynamics of Cross-Equatorial Flow.- 6.7.4. Equatorial Dry Zone.- 6.8. Monsoons.- 6.8.1. Definition and Global Perspective.- 6.8.2. Africa.- 6.8.3. Indian Ocean Sector.- 6.8.4. On the Heat and Moisture Budget of the Indian Monsoons.- 6.8.5. Numerical Modelling of the Indian Summer Monsoon.- 6.9. Zonal Circulations.- 6.10. Upper-Tropospheric Anticyclones.- 6.11. Wind Regimes of the Equatorial Stratosphere.- 6.12. Synthesis.- References.- 7. Climatology of Weather Systems.- 7.1. Clouds and Convection.- 7.2. Tropical Storms.- 7.3. Waves in the Easterlies.- 7.4. Squall Lines.- 7.5. Dust Storms of the Sudan.- 7.6. Monsoon Depressions.- 7.7. Subtropical Cyclones.- 7.8. Temporales of Pacific Central America.- 7.9. Cold Surges.- 7.10. Interannual Variability.- 7.11. Synthesis.- References.- 8. Interannual Variability of the Atmosphere-Ocean System.- 8.1. Surface Patterns of the Southern Oscillation.- 8.2. El Nino.- 8.3. Upper-Air Patterns of the Southern Oscillation.- 8.4. Rainfall Anomalies in Indonesia.- 8.5. Vagaries of the Indian Monsoon.- 8.6. The Secas of Northeast Brazil.- 8.7. Rainfall Variations in the Central American - Caribbean Region.- 8.8. Drought and Flood Regimes in Subsaharan Africa.- 8.9. Climate Anomalies at the Angola Coast.- 8.10. Hydrometeorological Anomalies in the Zaire (Congo) Basin.- 8.11. Time Scales of Climate Variability.- 8.12. Synthesis.- References.- 9. Climate Prediction.- 9.1. Indian Monsoon.- 9.2. Indonesian Rainfall.- 9.3. Hong Kong Climate.- 9.4. Southern Africa.- 9.5. Kenya Rainfall.- 9.6. Sahel Drought.- 9.7. The Droughts of Northeast Brazil.- 9.8. Rivers of Northern South America.- 9.9. El Nino.- 9.10. Tropical Storms.- 9.11. Numerical Modelling.- 9.12. Biological Consequences.- 9.13. Synthesis and Outlook.- References.- 10. The Human Impact.- 10.1. Deforestation.- 10.2. Land Use and Surface Albedo.- 10.3. Effects of Dust on Climate.- 10.4. Intentional Climate Modification.- 10.5. Ocean Climate and Fisheries.- 10.6. India.- 10.7. Northeast Brazil.- 10.8. Subsaharan Africa.- 10.9. The Use of Climate Prediction.- 10.10. Synthesis.- References.- 11. Tropical Glaciers and Climate.- 11.1. Spatial Patterns.- 11.2. History of Glacier Variations.- 11.3. Climatic Forcing and Terminus Response.- 11.4. Ice Cores.- 11.5. Synthesis.- References.- 12. Past Climates Of The Tropics.- 12.1. Causes of Climate Variations.- 12.2. Vegetation.- 12.3. Lakes.- 12.4. Glaciers.- 12.5. Deep-Sea Cores.- 12.6. Pacific and Australasia.- 12.7. The Indian Ocean and Surrounding Continents.- 12.8. Africa and the Adjacent Tropical Atlantic.- 12.9. Americas.- 12.10. Numerical Modelling.- 12.11. Synthesis.- References.- Author Index.
670 citations
TL;DR: In this paper, the authors investigated the origin and structure of easterly waves that form in the lower troposphere of North Africa and have a periodicity of 3-5 days.
Abstract: This study investigates the origin and structure of easterly waves that form in the lower troposphere of North Africa and have a periodicity of 3–5 days,. From June to early October these waves propagate across the Atlantic and occasionally reach the eastern Pacific. Although only a few of these disturbances actually intensify after reaching the Atlantic, they account for approximately half of the tropical cyclones that form in the Atlantic. Spectral analysis of five years of upper air data shows that African waves produce a spectral peak of the meridional wind at periods of 3–5 days with a maximum amplitude of 1–2 m sec−1 near 700 mb. These waves normally originate between Khartoum (32E) and Ft. Lamy (I5E) and affect a greater depth of the atmosphere as they propagate westward. Wind statistics at stations flanking the mountains in Ethiopia indicate that airflow over these mountains is not the cause of the easterly waves. This study shows that the African waves are directly related to the mid-tro...
668 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 14 |
| 2020 | 12 |
| 2019 | 15 |
| 2018 | 11 |
| 2017 | 12 |
| 2016 | 12 |