Understanding West African Monsoon Variability
Author : Ellen Berntell
Publisher :
Page : 0 pages
File Size : 47,21 MB
Release : 2023
Category :
ISBN : 9789180143110
Climate Variability
Author : Aondover Tarhule
Publisher : BoD – Books on Demand
Page : 218 pages
File Size : 18,4 MB
Release : 2013-08-28
Category : Science
ISBN : 9535111876
Book Description
As societies transition to evidence-based adaptation and management there is increasing recognition of the need for understanding climate change and variability dynamics and impacts at regional levels and for various activities. This book is a contribution toward that goal. Readers interested in climate change management will find detailed discussions of climatic variability dynamics in selected regions as well as new innovative ways of monitoring climate change, assessing climate risks, and predicting impacts. Those interested in refreshing the fundamentals of climate change and climate variability will find a very accessible review of the status of knowledge on the subject, including a balanced interrogation of available evidence. In an attempt to keep the book accessible, every effort was made to minimize technical jargon without compromising scientific accuracy. The result should be useful to researchers, practitioners, and policy makers.
Understanding Rainfall Variability Over West Africa and Climate Sensitivity in the Tropics
Author : Gang Zhang (Ph. D.)
Publisher :
Page : 135 pages
File Size : 22,32 MB
Release : 2015
Category :
ISBN :
Book Description
West African rainfall plays an important role in tropical climate and hydrological cycle. This study aims to advance our understanding of the West African rainfall across different timescales, from the diurnal cycle to interannual variations. Then, the study is extended to understand the climate sensitivity in the tropics with an increase of greenhouse gases. First, on a short timescale, the diurnal cycle of warm season rainfall over West Africa is investigated. In both the climatology and the 2006 case study, most of West Africa shows a single diurnal peak of rainfall in either the afternoon or at night. Afternoon rainfall peaks are associated with an unstable lower troposphere. Nocturnal rainfall peaks are associated with rainfall systems propagating westward. They occur most frequently about 3°-10° of longitude downstream of regions with afternoon rainfall peaks. Rainfall systems in the convection-permitting simulation show similar westward propagation with afternoon peaks associated with elevated topography and nocturnal peaks downstream of the topographic afternoon rainfall regions. However, the model fails to reproduce the observed afternoon rainfall peaks in several regions far away from the downstream of elevated topography. Second, on a longer timescale, the climatology and interannual variations of the West African monsoon demise are investigated using the Tropical Rainfall Measuring Mission and the Global Precipitation Climatology Project precipitation datasets along with the ERA-Interim reanalysis. During monsoon demise, the rainfall maximum progresses southward smoothly from the Sahel to the Gulf of Guinea. The climatological monsoon demise date is October 20th. The demise date varies between October 5th and 30th. An early (late) demise is associated with an anomalously strong (weak) North Atlantic subtropical high. The monsoon season total rainfall is found to be significantly correlated with the demise date. Finally, idealized regional model simulations are used to understand the climate sensitivity over the broad tropical region. The model is configured with idealized continents and oceans. With a doubling of CO2, the land and the ocean warm at different rates. The changes of the continental heat lows, subtropical highs and land-based rainfall in the tropics are explored and linked to the surface warming.
The Global Monsoon System
Author : Chih-Pei Chang
Publisher : World Scientific
Page : 609 pages
File Size : 44,69 MB
Release : 2011
Category : Nature
ISBN : 9814343412
Book Description
This book presents a current review of the science of monsoon research and forecasting. The contents are based on the invited reviews presented at the World Meteorological Organization''s Fourth International Workshop on Monsoons in late 2008, with subsequent manuscripts revised from 2009 to early 2010. The book builds on the concept that the monsoons in various parts of the globe can be viewed as components of an integrated global monsoon system, while emphasizing that significant region-specific characteristics are present in individual monsoon regions. The topics covered include all major monsoon regions and time scales (mesoscale, synoptic, intraseasonal, interannual, decadal, and climate change). It is intended to provide an updated comprehensive review of the current status of knowledge, modeling capability, and future directions in the research of monsoon systems around the world.
Understanding the Variability and Changes in West African Summer Monsoon Rainfall
Author : Akintomide Afolayan Akinsano
Publisher :
Page : 229 pages
File Size : 20,41 MB
Release : 2019
Category : Environmental engineering
ISBN :
Book Description
Influence of the Sea Surface Temperature Decadal Variability on Tropical Precipitation: West African and South American Monsoon
Author : Julián Villamayor
Publisher : Springer
Page : 238 pages
File Size : 46,16 MB
Release : 2019-07-05
Category : Science
ISBN : 3030203271
Book Description
In this book the Sea Surface Temperature (SST) patterns of decadal-to-multidecadal variability observed and simulated by 17 general circulation models (GCMs) are analyzed. Furthermore, their impact on precipitation in West Africa and South America and the atmospheric mechanisms involved are assessed. Through this analysis, the effect of external forcings on these impacts and the relative contribution of decadal-to-multidecadal variability patterns of SST to precipitation are presented in depth. Finally, a humid period in the West African region of the Sahel during the 19th century, previously little documented, is analyzed using an atmospheric GCM. The monsoons of West Africa and South America have shown changes in the timescales of a few decades. Previous work suggests a relationship with patterns of decadal-to-multidecadal variability of SST, such as global warming and the Atlantic and Pacific variability. However, the dynamics underlying this relationship and its simulation by current GCMs had not been addressed in a consistent manner. This is the main motivation of this book. The results of this book not only represent a great step forward in our understanding of the changes in the precipitation regimes of the studied regions, but they can also be of great help for the improvement of decadal prediction systems and the associated social consequences.
Meteorology of Tropical West Africa
Author : Douglas J. Parker
Publisher : John Wiley & Sons
Page : 490 pages
File Size : 48,95 MB
Release : 2017-04-24
Category : Science
ISBN : 1118391306
Book Description
Meteorology of tropical West Africa: the Forecasters’ Handbook presents the science and practice of weather forecasting for an important region of the tropics. Connecting basic theory with forecasting practice, the book provides a unique training volume for operational weather forecasters, and is also suitable for students of tropical meteorology. The West African region contains a number of archetypal climatic zones, meaning that the science of its weather and climate applies to many other tropical regions. West Africa also exhibits some of the world’s most remarkable weather systems, making it an inspiring region for students to investigate. The weather of West Africa affects human livelihoods on a daily basis, and can contribute to hardship, poverty and mortality. Therefore, the ability to understand and predict the weather has the potential to deliver significant benefits to both society and economies. The book includes comprehensive background material alongside documentation of weather forecasting methods. Many examples taken from observations of West African weather systems are included and online case-studies are referenced widely.
West African Monsoon Variability from a High-Resolution Paleolimnological Record (Lake Bosumtwi, Ghana).
Author : Timothy Michael Shanahan
Publisher :
Page : 770 pages
File Size : 25,27 MB
Release : 2006
Category :
ISBN :
Book Description
Instrumental and observational records of climate in West Africa suggest that this region may be susceptible to abrupt, decades-long drought events, with potentially catastrophic impacts for the people living in this region. However, because of the dearth of long, continuous and high quality climate records from sub-Saharan Africa, little is known about the long-term frequency and persistence of drought events in this region. It is also unclear whether observed 20th century droughts are natural or due to human impacts. In the present study, we use several complementary approaches to develop a high-resolution record of paleoclimatic changes in West Africa from the geological record preserved at Lake Bosumtwi, Ghana. Our results suggest that West Africa has undergone significant hydrologic variations over the last ca. 10,000 years. The dominant influence on hydrologic changes over this interval was changes in northern hemisphere summer insolation and the associated feedback processes acting in the oceans and on land. This led to a more northerly position of the Intertropical Convergence Zone (ITCZ) and increased precipitation during the early to mid-Holocene. In the late Holocene, a second increase in precipitation occurred along the Guinea coast as a result of the southward migration of the ITCZ from its northern position. This maximum was followed by an abrupt decrease in precipitation at ca. 2.5-3 kyr. The West African monsoon also varies on timescales from millennia to decades. Millennial and century-scale variations appear to be partly paced by changes in solar irradiance, either directly or indirectly. On decadal timescales, variability appears to be dominated by changes in Atlantic sea surface temperatures. The dominant mode is a ca. 40 year oscillation, which in strongly coherent and in phase with the Atlantic Multidecadal Oscillation (AMO). It is unclear from this study, however, if drought conditions over the last century are related to this multidecadal oscillation, or if they are forced by anthropogenic changes.
Adaptation to Climate Change and Variability in Rural West Africa
Author : Joseph A. Yaro
Publisher : Springer
Page : 249 pages
File Size : 26,99 MB
Release : 2016-04-12
Category : Science
ISBN : 3319314998
Book Description
This book presents conceptual and empirical discussions of adaptation to climate change/variability in West Africa. Highlighting different countries’ experiences in adaptation by different socio-economic groups and efforts at building their adaptive capacity, it offers readers a holistic understanding of adaptation on the basis of contextual and generic sources of adaptive capacity. Focusing on adaptation to climate change/variability is critical because the developmental challenges West Africa faces are increasingly intertwined with its climate history. Today, climate change is a major developmental issue for agrarian rural communities with high percentages of the population earning a living directly or indirectly from the natural environment. This makes them highly vulnerable to climate-driven ecological change, in addition to threats in the broader political economic context. It is imperative that rural people adapt to climate change, but their ability to successfully do so may be limited by competing risks and vulnerabilities. As such, elucidating those vulnerabilities and sources of strength with regard to the adaptive capacities needed to support successful adaptation and avoid maladaptation is critical for future policy formulation. Though the empirical discussion is geographically based on West Africa, its applicability in terms of the processes, structures, needs, strategies, and recommendations for policy transcends the region and provides useful lessons for understanding adaptation broadly in the developing world.
Understanding Precipitation Variability Over Africa
Author : Weiran Liu (Ph. D.)
Publisher :
Page : 320 pages
File Size : 14,58 MB
Release : 2019
Category :
ISBN :
Book Description
Understanding precipitation variability over Africa is important because this region experiences rainfall events that influence agriculture and economic infrastructure, and threaten lives regularly. This study aims to advance our understanding of African precipitation across different timescales, from diurnal cycle to interannual variations, using observations, reanalyses, and regional climate model simulations. First, we evaluate the role of MCSs in the total rainfall distribution as a function of season from a climatological perspective (1998-2014) over sub-Saharan northern Africa and examine how the diurnal cycle of rainfall changes with season. The percentages of the full TRMM precipitation delivered by MCSs have meridional structures in spring, fall and winter, while the percentages are homogenous in summer (>80%). The diurnal peaks are classified into three categories: single afternoon peak, continuous afternoon peak, and nocturnal peak. The continuous afternoon peak combines rainfall from two system types –one locally-generated and one propagating. The seasonality of the diurnal cycle is related to the seasonality of MCS lifetimes, and propagation speeds and directions. Second, a low-level jet, the West African westerly jet, is investigated over the West African coast. In the western Sahel (0°-10°W, 8°-18°N), the moisture flux associated with the jet is stronger than that associated with the southerly West African monsoon flow from July 5 to August 20 (45 days). The moisture budget analysis reveals that the seasonal evolution of the rainfall in this analysis region is associated with zonal moisture convergence related to changes of the jet. Finally, three sub-regions of the Indian Ocean in which SSTs significantly influence the equatorial East African short rains on interannual timescales are identified, and the physical processes of this influence are studied using regional climate model simulations. SSTAs in the western Indian Ocean exert a stronger influence on the short rains than central and eastern Indian Ocean SSTAs both in terms of the coverage of significantly-changed precipitation and the magnitude of the precipitation response. The mechanisms of this influence are diagnosed using atmospheric moisture budget and moist static energy analyses, with reference to Kelvin and Rossby wave generation as in the Gill model, but in the presence of complicated topography and nonzero background flows
